9 CFR 166.14 - Cleaning and disinfecting.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting. 166.14... AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.14 Cleaning and disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be...

Determining Exposure Factors of Anti-Fogging, Dye, Disinfectant, Repellent, and Preservative Products in Korea.

Science.gov (United States)

Lee, Daeyeop; Kim, Joo-Hyon; Kim, Taksoo; Yoon, Hyojung; Jo, Areum; Lee, Byeongwoo; Lim, Hyunwoo; Kim, Pilje; Seo, Jungkwan

2018-01-30

Reliable exposure factors are essential to determine health risks posed by chemicals in consumer products. We analyzed five risk-concerned product categories (anti-fogging, dye, disinfectant, repellent, and preservative products) for 13 products (three car anti-fogging products, a lens anti-fogging product, two car dye products, two drain disinfectants, an air conditioner disinfectant, a chlorine-based disinfectant, a fabric repellent, an insect repellent for food, and a wood preservative) considered to be of high risk in order to determine exposure factors via web surveys and estimation of amount of product. Among the 3000 participants (1482 (49%) men) aged ≥19 years, drain disinfectants were used most frequently (38.2%); the rate of usage of the other products ranged between 1.1-24.0%. The usage rates for the consumer products differed by sex, age, income, and education. Some consumer products such as car and lens anti-fogging products, chlorine-based disinfectants, fabric repellents, and drain disinfectants were regularly used more than once a month, while car dye products, air conditioner disinfectants, insect repellents for food, and wood preservatives were not regularly used owing to the specific product purposes and seasonal needs. Our results could be used for managing or controlling chemical substances in consumer products and conducting accurate exposure assessments.

The impact of iodinated X-ray contrast agents on formation and toxicity of disinfection by-products in drinking water.

Science.gov (United States)

Jeong, Clara H; Machek, Edward J; Shakeri, Morteza; Duirk, Stephen E; Ternes, Thomas A; Richardson, Susan D; Wagner, Elizabeth D; Plewa, Michael J

2017-08-01

The presence of iodinated X-ray contrast media (ICM) in source waters is of high concern to public health because of their potential to generate highly toxic disinfection by-products (DBPs). The objective of this study was to determine the impact of ICM in source waters and the type of disinfectant on the overall toxicity of DBP mixtures and to determine which ICM and reaction conditions give rise to toxic by-products. Source waters collected from Akron, OH were treated with five different ICMs, including iopamidol, iopromide, iohexol, diatrizoate and iomeprol, with or without chlorine or chloramine disinfection. The reaction product mixtures were concentrated with XAD resins and the mammalian cell cytotoxicity and genotoxicity of the reaction mixture concentrates was measured. Water containing iopamidol generated an enhanced level of mammalian cell cytotoxicity and genotoxicity after disinfection. While chlorine disinfection with iopamidol resulted in the highest cytotoxicity overall, the relative iopamidol-mediated increase in toxicity was greater when chloramine was used as the disinfectant compared with chlorine. Four other ICMs (iopromide, iohexol, diatrizoate, and iomeprol) expressed some cytotoxicity over the control without any disinfection, and induced higher cytotoxicity when chlorinated. Only iohexol enhanced genotoxicity compared to the chlorinated source water. Copyright © 2017. Published by Elsevier B.V.

Halogenated by-products of disinfecting ozonised recreational waters; Subproductos halaogenados de desinfeccion en aguas recreacionales ozonizadas

Energy Technology Data Exchange (ETDEWEB)

Goma i Huguet, A.; Quintana i Comte, J.; Soler i Vilaro, J.

2005-07-01

Recreational water like the present in swimming pools suffers, more than water from supply, formation of certain by-products in the local disinfection system because a mechanism of accumulation. Using advanced oxidation process, like onization, drives to a reduction of such an effect. Assessment of the presence of these disinfection by-products with and without onization, as well as the discussion of certain key aspects of how to ozonate, are the aim of this paper. (Author) 7 refs.

List M: Registered Antimicrobial Products with Label Claims for Avian (Bird) Flu Disinfectants

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These EPA disinfectant products are registered and labeled with a claim to inactivate Avian influenza A viruses on hard, non-porous surfaces. The label specifies the use sites (e.g., poultry houses and farm premises) for application of the product.

Guidance to Companies on Referring to Registered Disinfectant Products that Meet the CDC Criteria for Use Against the Ebola Virus

Science.gov (United States)

There are no EPA-registered products with label claims against the Ebola virus, but enveloped viruses such as Ebola are susceptible to many hospital disinfectants used to disinfect hard, non-porous surfaces. CDC guidance addresses use of such products.

[Survey of synthetic disinfectants in grapefruit seed extract and its compounded products].

Science.gov (United States)

Sugimoto, Naoki; Tada, Atsuko; Kuroyanagi, Masanori; Yoneda, Yuko; Yun, Young Sook; Kunugi, Akira; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Ken-Ichi

2008-02-01

Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.

Genotoxic Effects in Swimmers Exposed to Disinfection By-products in Indoor Swimming Pool

Science.gov (United States)

BACKGROUND: Exposure to disinfection by-products (DBPs) in drinking water has been associated with cancer risk, and a recent study found an increased bladder cancer risk among subjects attending swimming pools. OBJECTIVES: To evaluate whether swimming in pools is associated with ...

Socioeconomic status and exposure to disinfection by-products in drinking water in Spain

Directory of Open Access Journals (Sweden)

Serra Consol

2011-03-01

Full Text Available Abstract Background Disinfection by-products in drinking water are chemical contaminants that have been associated with cancer and other adverse effects. Exposure occurs from consumption of tap water, inhalation and dermal absorption. Methods We determined the relationship between socioeconomic status and exposure to disinfection by-products in 1271 controls from a multicentric bladder cancer case-control study in Spain. Information on lifetime drinking water sources, swimming pool attendance, showering-bathing practices, and socioeconomic status (education, income was collected through personal interviews. Results The most highly educated subjects consumed less tap water (57% and more bottled water (33% than illiterate subjects (69% and 17% respectively, p-value = 0.003. These differences became wider in recent time periods. The time spent bathing or showering was positively correlated with attained educational level (p Conclusions The most highly educated subjects were less exposed to chlorination by-products through ingestion but more exposed through dermal contact and inhalation in pools and showers/baths. Health risk perceptions and economic capacity may affect patterns of water consumption that can result in differences in exposure to water contaminants.

Environmental and personal determinants of the uptake of disinfection by-products during swimming

NARCIS (Netherlands)

Font-Ribera, Laia; Kogevinas, Manolis; Schmalz, Christina; Zwiener, Christian; Marco, Esther; Grimalt, Joan O; Liu, Jiaqi; Zhang, Xiangru; Mitch, William; Critelli, Rossana; Naccarati, Alessio; Heederik, Dick; Spithoven, Jack; Arjona, Lourdes; de Bont, Jeroen; Gracia-Lavedan, Esther; Villanueva, Cristina M

BACKGROUND: Trihalomethanes (THMs) in exhaled breath and trichloroacetic acid (TCAA) in urine are internal dose biomarkers of exposure to disinfection by-products (DBPs) in swimming pools. OBJECTIVE: We assessed how these biomarkers reflect the levels of a battery of DBPs in pool water and

Characterization of Cleaning and Disinfecting Tasks and Product Use Among Hospital Occupations

Science.gov (United States)

Saito, Rena; Virji, M. Abbas; Henneberger, Paul K.; Humann, Michael J.; LeBouf, Ryan F.; Stanton, Marcia L.; Liang, Xiaoming; Stefaniak, Aleksandr B.

2016-01-01

Background Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations. Methods Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets. Results Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108–177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for > 100 min/shift. Conclusions This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals. PMID:25351791

Nano-silver in drinking water and drinking water sources: stability and influences on disinfection by-product formation.

Science.gov (United States)

Tugulea, A-M; Bérubé, D; Giddings, M; Lemieux, F; Hnatiw, J; Priem, J; Avramescu, M-L

2014-10-01

Nano-silver is increasingly used in consumer products from washing machines and refrigerators to devices marketed for the disinfection of drinking water or recreational water. The nano-silver in these products may be released, ending up in surface water bodies which may be used as drinking water sources. Little information is available about the stability of the nano-silver in sources of drinking water, its fate during drinking water disinfection processes, and its interaction with disinfection agents and disinfection by-products (DBPs). This study aims to investigate the stability of nano-silver in drinking water sources and in the finished drinking water when chlorine and chloramines are used for disinfection and to observe changes in the composition of DBPs formed when nano-silver is present in the source water. A dispersion of nano-silver particles (10 nm; PVP-coated) was used to spike untreated Ottawa River water, treated Ottawa River water, organic-free water, and a groundwater at concentrations of 5 mg/L. The diluted dispersions were kept under stirred and non-stirred conditions for up to 9 months and analyzed weekly using UV absorption to assess the stability of the nano-silver particles. In a separate experiment, Ottawa River water containing nano-silver particles (at 0.1 and 1 mg/L concentration, respectively) was disinfected by adding sodium hypochlorite (a chlorinating agent) in sufficient amounts to maintain a free chlorine residual of approximately 0.4 mg/L after 24 h. The disinfected drinking water was then quenched with ascorbic acid and analyzed for 34 neutral DBPs (trihalomethanes, haloacetonitriles, haloacetaldehydes, 1,1 dichloro-2-propanone, 1,1,1 trichloro-2-propanone, chloropicrin, and cyanogen chloride). The results were compared to the profile of DBPs obtained under the same conditions in the absence of nano-silver and in the presence of an equivalent concentration of Ag(+) ions (as AgNO3). The stability of the nano-silver dispersions in

Cleaning and Disinfection of Bacillus cereus Biofilm.

Science.gov (United States)

Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

2016-01-01

Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant

Energy Technology Data Exchange (ETDEWEB)

Serrano, Maria; Montesinos, Isabel; Cardador, M.J.; Silva, Manuel; Gallego, Mercedes, E-mail: mercedes.gallego@uco.es

2015-06-01

In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15–50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%). - Highlights: • Occurrence of 46 regulated and non-regulated DBPs through a DWTP was

Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant

International Nuclear Information System (INIS)

Serrano, Maria; Montesinos, Isabel; Cardador, M.J.; Silva, Manuel; Gallego, Mercedes

2015-01-01

In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15–50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%). - Highlights: • Occurrence of 46 regulated and non-regulated DBPs through a DWTP was

Disinfection by-products/precursor control using an innovative treatment process -- high energy electron beam irradiation

International Nuclear Information System (INIS)

Sawal, K.; Millington, B.; Slifker, R.A.; Cooper, W.J.; Nickelsen, M.G.; Kurucz, C.N.; Waite, T.D.

1993-01-01

When waters containing naturally occurring humic substances, precursors, are chlorinated, reaction (disinfection) by-products (DBPs) that may compromise the chemical water quality of the drinking water are formed. Two options exist for the treatment of THMs and other DBPs, removal of precursor material prior to chlorination, or destruction of the by-products once they are formed. The authors have initiated a study using an innovative process, high energy electron beam irradiation, as an alternative treatment for the destruction of toxic organic compounds. Preliminary studies indicated that the process would also be effective in the removal of precursors. An added advantage of this process is that is would serve as a primary disinfectant, destroying any toxic compounds in the source water and may assist in the removal of algae and cyanobacteria toxins. This paper discusses studies in precursor removal and control of THMs

Acanthamoeba polyphaga resuscitates viable non-culturable Legionella pneumophila after disinfection.

Science.gov (United States)

García, María Teresa; Jones, Snake; Pelaz, Carmen; Millar, Richard D; Abu Kwaik, Yousef

2007-05-01

Amoebae are the natural hosts for Legionella pneumophila and play essential roles in bacterial ecology and infectivity to humans. When L. pneumophila colonizes an aquatic installation, it can persist for years despite repeated treatments with disinfectants. We hypothesized that freshwater amoebae play an important role in bacterial resistance to disinfectants, and in subsequent resuscitation of viable non-culturable (VNC) L. pneumophila that results in re-emergence of the disease-causing strain in the disinfected water source. Our work showed that in the absence of Acanthamoeba polyphaga, seven L. pneumophila strains became non-culturable after treatment by 256 p.p.m. of sodium hypochlorite (NaOCl). In contrast, intracellular L. pneumophila within A. polyphaga was resistant to 1024 p.p.m. of NaOCl. In addition, L. pneumophila-infected A. polyphaga exhibited increased resistance to NaOCl. When chlorine-sterilized water samples were co-cultured with A. polyphaga, the non-culturable L. pneumophila were resuscitated and proliferated robustly within A. polyphaga. Upon treatment by NaOCl, uninfected amoebae differentiated into cysts within 48 h. In contrast, L. pneumophila-infected A. polyphaga failed to differentiate into cysts, and L. pneumophila was never detected in cysts of A. polyphaga. We conclude that amoebic trophozoites protect intracellular L. pneumophila from eradication by NaOCl, and play an essential role in resuscitation of VNC L. pneumophila in NaOCl-disinfected water sources. Intracellular L. pneumophila within trophozoites of A. polyphaga block encystation of the amoebae, and the resistance of both organisms to NaOCl is enhanced. To ensure long-term eradication and complete loss of the VNC state of L. pneumophila, we recommend that Legionella-protozoa co-culture should be an important tool to ensure complete loss of the VNC state of L. pneumophila.

Evidence of arsenic release promoted by disinfection by-products within drinking-water distribution systems.

Science.gov (United States)

Andra, Syam S; Makris, Konstantinos C; Botsaris, George; Charisiadis, Pantelis; Kalyvas, Harris; Costa, Costas N

2014-02-15

Changes in disinfectant type could trigger a cascade of reactions releasing pipe-anchored metals/metalloids into finished water. However, the effect of pre-formed disinfection by-products on the release of sorbed contaminants (arsenic-As in particular) from drinking water distribution system pipe scales remains unexplored. A bench-scale study using a factorial experimental design was performed to evaluate the independent and interaction effects of trihalomethanes (TTHM) and haloacetic acids (HAA) on arsenic (As) release from either scales-only or scale-biofilm conglomerates (SBC) both anchored on asbestos/cement pipe coupons. A model biofilm (Pseudomonas aeruginosa) was allowed to grow on select pipe coupons prior experimentation. Either TTHM or HAA individual dosing did not promote As release from either scales only or SBC, detecting water. In the case of scales-only coupons, the combination of the highest spike level of TTHM and HAA significantly (pwater in pipe networks remains to be investigated in the field. Copyright © 2013 Elsevier B.V. All rights reserved.

Activity of disinfectants and biofilm production of Corynebacterium pseudotuberculosis

Directory of Open Access Journals (Sweden)

Maria da C.A. Sá

2013-11-01

Full Text Available To verify the occurrence of caseous lymphadenitis in sheep and goats on farms of Pernambuco, Brazil, and in animals slaughtered in two Brazilian cities (Petrolina/PE and Juazeiro/BA, and to characterize the susceptibility profile of Corynebacterium pseudotuberculosis to disinfectants and antimicrobials, and its relationship with biofilm production were the objectives of this study. 398 samples were tested for sensitivity to antimicrobial drugs, disinfectants, and biofilm production. Among the 108 samples collected on the properties, 75% were positive for C. pseudotuberculosis. Slaughterhouse samples indicated an occurrence of caseous lymphadenitis in 15.66% and 6.31% for animals slaughtered in Petrolina and Juazeiro respectively. With respect to antimicrobials, the sensitivity obtained was 100% for florfenicol and tetracycline; 99.25% for enrofloxacin, ciprofloxacin and lincomycin; 98.99% for cephalothin; 98.74% for norfloxacin and sulfazotrim; 97.74% for gentamicin; 94.22% for ampicillin; 91.71% for amoxicillin; 91.21% for penicillin G; 89.19% for neomycin and 0% for novobiocin. In analyzes with disinfectants, the efficiency for chlorhexidine was 100%, 97.20% for quaternary ammonium, 87.40% for chlorine and 84.40% for iodine. 75% of the isolates were weak or non-biofilm producers. For the consolidated biofilm, found that iodine decreased biofilm formation in 13 isolates and quaternary ammonia in 11 isolates. The reduction of the biofilm formation was observed for iodine and quaternary ammonium in consolidated biofilm formation in 33% and 28% of the isolates, respectively. The results of this study highlight the importance of establishing measures to prevent and control the disease.

A comparison of disinfection by-products formation during sequential or simultaneous disinfection of surface waters with chlorine dioxide and chlor(am)ine.

Science.gov (United States)

Shi, Yanwei; Ling, Wencui; Qiang, Zhimin

2013-01-01

The effect of chlorine dioxide (ClO2) oxidation on the formation of disinfection by-products (DBPs) during sequential (ClO2 pre-oxidation for 30 min) and simultaneous disinfection processes with free chlorine (FC) or monochloramine (MCA) was investigated. The formation of DBPs from synthetic humic acid (HA) water and three natural surface waters containing low bromide levels (11-27 microg/L) was comparatively examined in the FC-based (single FC, sequential ClO2-FC, and simultaneous ClO2/FC) and MCA-based (single MCA, ClO2-MCA, and ClO2/MCA) disinfection processes. The results showed that much more DBPs were formed from the synthetic HA water than from the three natural surface waters with comparative levels of dissolved organic carbon. In the FC-based processes, ClO2 oxidation could reduce trihalomethanes (THMs) by 27-35% and haloacetic acids (HAAs) by 14-22% in the three natural surface waters, but increased THMs by 19% and HAAs by 31% in the synthetic HA water after an FC contact time of 48 h. In the MCA-based processes, similar trends were observed although DBPs were produced at a much lower level. There was an insignificant difference in DBPs formation between the sequential and simultaneous processes. The presence of a high level of bromide (320 microg/L) remarkably promoted the DBPs formation in the FC-based processes. Therefore, the simultaneous disinfection process of ClO2/MCA is recommended particularly for waters with a high bromide level.

Drinking water disinfection by means of ultraviolet radiation

International Nuclear Information System (INIS)

Gelzhaeuser, P.; Bewig, F.; Holm, K.; Kryschi, R.; Reich, G.; Steuer, W.

1985-01-01

The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice. (orig./PW) [de

Ozone and hydrogen peroxide applications for disinfection by-products control in drinking water

International Nuclear Information System (INIS)

Collivignarelli, C.; Sorlini, S.; Riganti, V.

2001-01-01

A great interest has been developed during the last years for ozone in drinking water treatments thanks to its strong oxidant and disinfectant power and for its efficiency in disinfection by-products (DBPs) precursors removal. However ozonization produces some specific DBPs, such as aldehydes and ketones; moreover, the presence of bromide in raw water engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. In this paper the combination of hydrogen peroxide with ozone (known as peroxone process) and the ozone alone process were experimented on one surface water coming from the lake of Brugneto (Genova) in order to investigate bromate formation and trihalomethanes precursors removal during the oxidation process. The results show that the advanced peroxone process can be applied for bromate reduction (about 30-40%) with better results in comparison with the ozone alone process, while no advantages are shown for THMs precursors removal. The addition of in-line filtration step after pre-oxidation improves both bromate and THMs precursors removal, particularly with increasing hydrogen peroxide/ozone ratio in the oxidation step [it

Baby bottle steam sterilizers for disinfecting home nebulizers inoculated with non-tuberculous mycobacteria.

Science.gov (United States)

Towle, D; Callan, D A; Lamprea, C; Murray, T S

2016-03-01

Non-tuberculous mycobacteria (NTMb), present in environmental water sources, can contribute to respiratory infection in patients with chronic pulmonary disease. Contaminated nebulizers are a potential source of respiratory infection. Treatment with baby bottle steam sterilizers disinfects home nebulizers inoculated with bacterial pathogens but whether this method works for disinfection of NTMb is unclear. Baby bottle steam sterilization was compared with vigorous water washing for disinfecting home nebulizers inoculated with NTMb mixed with cystic fibrosis sputum. No NTMb was recovered from any nebulizers after steam treatment whereas viable NTMb grew after water washing, demonstrating that steam sterilization effectively disinfects NTMb-inoculated nebulizers. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Analysis, Occurrence and Toxicity of Haloacetaldehydes in Drinking Waters: Iodacetaldehyde as an Emerging Disinfection ByProduct.

Science.gov (United States)

Chlorinated and brominated haloacetaldehydes (HALs) are consideredthe 3rd largest class of disinfection by-products (DBPs) by weight. The iodinatedHAL, iodoacetaldehyde, has been recently reported as an emerging DBP infinished drinking waters. Overall, iodinated DBPs, e.g., iodoa...

Drinking water and biofilm disinfection by Fenton-like reaction.

Science.gov (United States)

Gosselin, F; Madeira, L M; Juhna, T; Block, J C

2013-10-01

A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhanced coagulation with powdered activated carbon or MIEX secondary treatment: a comparison of disinfection by-product formation and precursor removal.

Science.gov (United States)

Watson, Kalinda; Farré, Maria José; Knight, Nicole

2015-01-01

The removal of both organic and inorganic disinfection by-product (DBP) precursors prior to disinfection is important in mitigating DBP formation, with halide removal being particularly important in salinity-impacted water sources. A matrix of waters of variable alkalinity, halide concentration and dissolved organic carbon (DOC) concentration were treated with enhanced coagulation (EC) followed by anion exchange (MIEX resin) or powdered activated carbon (PAC) and the subsequent disinfection by-product formation potentials (DBP-FPs) assessed and compared to DBP-FPs for untreated samples. Halide and DOC removal were also monitored for both treatment processes. Bromide and iodide adsorption by MIEX treatment ranged from 0 to 53% and 4-78%, respectively. As expected, EC and PAC treatments did not remove halides. DOC removal by EC/PAC was 70 ± 10%, while EC/MIEX enabled a DOC removal of 66 ± 12%. Despite the halide removals achieved by MIEX, increases in brominated disinfection by-product (Br-DBP) formation were observed relative to untreated samples, when favourable Br:DOC ratios were created by the treatment. However, the increases in formation were less than what was observed for the EC/PAC treated waters, which caused large increases in Br-DBP formation when high Br-DBP-forming water quality conditions occurred. The formation potential of fully chlorinated DBPs decreased after treatment in all cases.

Evaluation of the water disinfection by-product dichloroacetonitrile-induced biochemical, oxidative, histopathological, and mitochondrial functional alterations: Subacute oral toxicity in rats.

Science.gov (United States)

Dong, Ying; Li, Fang; Shen, Haijun; Lu, Rongzhu; Yin, Siqi; Yang, Qi; Li, Zhuangfa; Wang, Suhua

2018-03-01

Dichloroacetonitrile (DCAN), an emerging nitrogenous disinfection by-product, is more genotoxic and cytotoxic than the currently regulated carbonaceous disinfection by-products such as haloacetic acids. Few mechanistic studies have been conducted on the hepatic and renal toxicities of DCAN. This study examined the clinical biochemical, hematological, histopathological, oxidative, and mitochondrial functional alterations to evaluate the systematic toxicity after subacute oral exposure of 11 or 44 mg/kg/day in rats for 28 days. Body and spleen weights were lower, and organ-to-body weight ratios of the liver and kidney were higher in rats administered 44-mg/kg DCAN than in controls. The activities of serum alanine aminotransferase and alkaline phosphatase, and concentrations of blood serum urea nitrogen and retinol-binding protein were increased in rats administered 44-mg/kg DCAN compared with those of controls, thereby indicating hepatic and renal damage in this group. This was confirmed by histopathological alterations, including hepatic sinus dilation, extensive hemorrhage, vacuolar degeneration in the liver and glomerulus hemorrhage, and renal tubular swelling, in DCAN-exposed rats. Exposure to 44-mg/kg DCAN induced hepatic oxidative damage shown by the significant increase in malonaldehyde levels, a poisonous product of lipid peroxidation. Exposure to 44-mg/kg DCAN significantly increased hepatic glutathione content and mitochondrial bioenergy as noted by the elevation of mitochondrial membrane potential and cytochrome c oxidase activity, which might be attributed to compensatory pathophysiologic responses to DCAN-induced hepatic mitochondrial damage.

What's in The Pool? A Comprehensive Identification Of Disinfection By-Products and Assessment of Mutagenicity of Chlorinated and Brominated Swimming Pool Water

Science.gov (United States)

Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. We performed a compreh...

What's in the pool? A comprehensive identification of disinfection by-products and assessment of mutagenicity of chlorinated and brominated swimming pool water

NARCIS (Netherlands)

Richardson, S.D.; Demarini, D.M.; Kogevinas, M.; Fernandez, P.; Marco, E.; Lourencetti, C.; Balleste, C.; Heederik, D.|info:eu-repo/dai/nl/072910542; Meliefste, K.; McKague, A.B.; Marcos, R.; Font-Ribera, L.; Grimalt, J.O.; Villanueva, C.M.

2010-01-01

BACKGROUND: Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. OBJECTIVES: We performed a

Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

Science.gov (United States)

Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

2017-06-01

The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

New chlorinated amphetamine-type-stimulants disinfection-by-products formed during drinking water treatment.

Science.gov (United States)

Huerta-Fontela, Maria; Pineda, Oriol; Ventura, Francesc; Galceran, Maria Teresa

2012-06-15

Previous studies have demonstrated high removal rates of amphetamine-type-stimulants (ATSs) through conventional drinking water treatments; however the behaviour of these compounds through disinfection steps and their transformation into disinfection-by-products (DBPs) is still unknown. In this work, for the first time, the reactivity of some ATSs such as amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) with chlorine has been investigated under simulated and real drinking water treatment conditions in order to evaluate their ability to give rise to transformation products. Two new DBPs from these illicit drugs have been found. A common chlorinated-by-product (3-chlorobenzo)-1,3-dioxole, was identified for both MDA and MDEA while for MDMA, 3-chlorocatechol was found. The presence of these DBPs in water samples collected through drinking water treatment was studied in order to evaluate their formation under real conditions. Both compounds were generated through treatment from raw river water samples containing ATSs at concentration levels ranging from 1 to 15 ng/L for MDA and from 2.3 to 78 ng/L for MDMA. One of them, (3-chlorobenzo)-1,3-dioxole, found after the first chlorination step, was eliminated after ozone and GAC treatment while the MDMA DBP mainly generated after the postchlorination step, showed to be recalcitrant and it was found in final treated waters at concentrations ranging from 0.5 to 5.8 ng/L. Copyright © 2012 Elsevier Ltd. All rights reserved.

Health impact of disinfection by-products in swimming pools

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Cristina M. Villanueva

2012-12-01

Full Text Available This article is focused on the epidemiological evidence on the health impacts related to disinfection by-products (DBPs in swimming pools, which is a chemical hazard generated as an undesired consequence to reduce the microbial pathogens. Specific DBPs are carcinogenic, fetotoxic and/or irritant to the airways according to experimental studies. Epidemiological evidence shows that swimming in pools during pregnancy is not associated with an increased risk of reproductive outcomes. An epidemiological study suggested an increased risk of bladder cancer with swimming pool attendance, although evidence is inconclusive. A higher prevalence of respiratory symptoms including asthma is found among swimming pool workers and elite swimmers, although the causality of this association is unclear. The body of evidence in children indicates that asthma is not increased by swimming pool attendance. Overall, the available knowledge suggests that the health benefits of swimming outweigh the potential health risks of chemical contamination. However, the positive effects of swimming should be enhanced by minimising potential risks.

40 CFR 141.72 - Disinfection.

Science.gov (United States)

2010-07-01

... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.72 Disinfection. A public water... the direct influence of surface water and provides filtration treatment must provide disinfection...) Disinfection requirements for public water systems which provide filtration. Each public water system that...

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters

DEFF Research Database (Denmark)

Cheema, Waqas Akram; Manasfi, Tarek; Kaarsholm, Kamilla Marie Speht

2017-01-01

Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has...

Effect of drinking water disinfection by-products in human peripheral blood lymphocytes and sperm.

Science.gov (United States)

Ali, Aftab; Kurzawa-Zegota, Malgorzata; Najafzadeh, Mojgan; Gopalan, Rajendran C; Plewa, Michael J; Anderson, Diana

2014-12-01

Drinking water disinfection by-products (DBPs) are generated by the chemical disinfection of water and may pose hazards to public health. Two major classes of DBPs are found in finished drinking water: haloacetic acids (HAAs) and trihalomethanes (THMs). HAAs are formed following disinfection with chlorine, which reacts with iodide and bromide in the water. Previously the HAAs were shown to be cytotoxic, genotoxic, mutagenic, teratogenic and carcinogenic. To determine the effect of HAAs in human somatic and germ cells and whether oxidative stress is involved in genotoxic action. In the present study both somatic and germ cells have been examined as peripheral blood lymphocytes and sperm. The effects of three HAA compounds: iodoacetic acid (IAA), bromoacetic acid (BAA) and chloroacetic acid (CAA) were investigated. After determining appropriate concentration responses, oxygen radical involvement with the antioxidants, butylated hydroxanisole (BHA) and the enzyme catalase, were investigated in the single cell gel electrophoresis (Comet) assay under alkaline conditions, >pH 13 and the micronucleus assay. In the Comet assay, BHA and catalase were able to reduce DNA damage in each cell type compared to HAA alone. In the micronucleus assay, micronuclei (MNi) were found in peripheral lymphocytes exposed to all three HAAs and catalase and BHA were in general, able to reduce MNi induction, suggesting oxygen radicals play a role in both assays. These observations are of concern to public health since both human somatic and germ cells show similar genotoxic responses. Copyright © 2014. Published by Elsevier B.V.

Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

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Sattar, S A; Springthorpe, V S; Karim, Y; Loro, P

1989-06-01

The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were selected for this study based on the findings of an earlier investigation with a human rotavirus. After 1 min exposure to 20 microliters of the disinfectant, the virus from the disks was immediately eluted into tryptose phosphate broth and plaque assayed. Using an efficacy criterion of a 3 log10 or greater reduction in virus infectivity titre and irrespective of the virus suspending medium, only the following five disinfectants proved to be effective against all the four viruses tested: (1) 2% glutaraldehyde normally used as an instrument soak, (2) a strongly alkaline mixture of 0.5% sodium o-benzyl-p-chlorophenate and 0.6% sodium lauryl sulphate, generally used as a domestic disinfectant cleaner for hard surfaces, (3) a 0.04% solution of a quaternary ammonium compound containing 7% hydrochloric acid, which is the basis of many toilet bowl cleaners, (4) chloramine T at a minimum free chlorine level of 3000 p.p.m. and (5) sodium hypochlorite at a minimum free chlorine concentration of 5000 p.p.m. Of those chemicals suitable for use as topical antiseptics, 70% ethanol alone or products containing at least 70% ethanol were ineffective only against coxsackievirus B3. These results emphasize the care needed in selecting chemical disinfectants for routine use in infection control.

Origin of low-molecular mass aldehydes as disinfection by-products in beverages.

Science.gov (United States)

Serrano, María; Gallego, Mercedes; Silva, Manuel

2017-09-01

A novel, simple and automatic method based on static headspace-gas chromatography-mass spectrometry has been developed to determine 10 low-molecular mass aldehydes that can be found in beverages, coming from the treated water used in their production. These aldehydes are the most frequently found in treated water as water disinfection by-products, so they can be used as indicators of the addition of treated water to beverages. The study covered a large number of fruit juices and soft drinks. The presence of the whole array of analytes is related to the contact with treated water during beverage production, mainly by the addition of treated water as ingredient. In particular, propionaldehyde, valeraldehyde and benzaldehyde can be used as indicators of the addition of treated water in these kinds of beverages. Among the ten aldehydes, only formaldehyde and acetaldehyde are naturally present in all kinds of fruit, and their concentrations are related to stage of the ripening of the fruit.

MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

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The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

EPIDEMIOLOGIC EVALUATION OF THE POTENTIAL ASSOCIATION BETWEEN EXPOSURE TO DRINKING WATER DISINFECTION BY-PRODUCTS (DBP) AND SEMEN QUALITY

Science.gov (United States)

Epidemiologic Evaluation of the Potential Association between Exposure to Drinking Water Disinfection By-Products and Semen Quality*Morris, R; +Olshan, A; +Lansdell, L; *Jeffay, S; *Strader, L; *Klinefelter, G; *Perreault, S.* U.S. EPA/ORD/NHEERL/RTD/GEEBB, Research ...

The study of interrelationship between raw water quality parameters, chlorine demand and the formation of disinfection by-products

Science.gov (United States)

Abdullah, Md. Pauzi; Yee, Lim Fang; Ata, Sadia; Abdullah, Abass; Ishak, Basar; Abidin, Khairul Nidzham Zainal

Disinfection is the most crucial process in the treatment of drinking water supply and is the final barrier against bacteriological impurities in drinking water. Chlorine is the primary disinfectant used in the drinking water treatment process throughout Malaysia. However, the occurrence of various disinfection by-products such as trihalomethanes (THM) and haloacetic acids created a major issue on the potential health hazards which may pose adverse health effects in both human and animals. To simulate real water treatment conditions and to represent the conditions inherent in a tropical country, this study was performed at an urbanized water treatment plant with a daily production of about 549,000 m 3 of treated water. The purpose of this work is to examine the relationship between the water quality parameters in the raw water with chlorine demand and the formation of disinfection by-products. This study also investigated the possibility of the statistical model applications for the prediction of chlorine demand and the THM formation. Two models were developed to estimate the chlorine demand and the THM formation. For the statistical evaluation, correlation and simple linear regression analysis were conducted using SPSS. The results of Kolmogorov-Smirnov test for the estimation of goodness-of-fit of the dependent variables of the models to the normal distribution showed that all the dependent variables followed the normal distribution at significance level of 0.05. Good linear correlations were observed between the independent parameters and formation of THM and the chlorine demand. This study also revealed that ammonia and the specific ultraviolet absorbent (SUVA) were the function of chlorine consumption in the treatment process. Chlorine dosage and SUVA increase the yield of THM. Chlorine demand and THM formation was moderately sensitive, but significant to the pH. The level of significance ( α) for the statistical tests and the inclusion of a variable in the

Production of T-2 toxin and deoxynivalenol in the presence of different disinfectants

Directory of Open Access Journals (Sweden)

Dana Hrubošová

2015-03-01

Full Text Available The aim of the work was to examine the effect of different disinfectants on production trichothecenes (especially of T-2 toxin and deoxynivalenol. Lipophilicity, chemical structure, the presence of bioactive groups and functional groups in their structure modifies biological activity and toxic potency of trichothecenes. For this reason, limits have been established designating maximum levels of mycotoxins in cereals while maintaining proper growing practices. Appropriate nutritive media were prepared with different concentration of tested disinfectants (Desanal A  plus, ProCura spray and Guaa-Pool and were inoculated using  Fusarium strains. The density of  Fusarium was 105 spores per mililitre. Nutrient media was cultivated at 15 °C and 25 °C for seven days. The strains of Fusarium graminearum CCM F-683 and Fusarium species (isolated from barley produced quantities of deoxynivalenol. Fusarium poae CCM F-584 and Fusarium species (isolated from malthouse air produced quantities of T-2 toxin. Desanal A plus prevented Fusarium growth and production of T-2 toxin and deoxynivalenol at the concentration 10%. It is an alkaline disinfectant on the basis of active chlorine and the surfactant that contains ˂5% of NaClO. ProCura spray at the concentration 0.6% proved to be very effective. This disinfectant contains 35% of propan-1-ol and 25% of propan-2-ol.  Guaa-Pool at the concentration 0.004% proved to be very effective. It is a polymeric disinfectant with anion surface-acting agent and it contains ˂0.9% of polyhexamethylene guanidine hydrochloride and ˂0.2% of alkyl (C12-C16 dimethylbenzyl ammonium chloride. Lower contentration of  disinfectants that  not prevented growth of Fusarium caused higher production  of T-2 toxin and deoxynivalenol. The contents of T-2 toxin and deoxynivalenol were analyzed by enzyme-linked immunosorbent assay (ELISA using commercially produced kits (Agra Quant® Deoxynivalenol Test kit and Agra Quant® T-2 toxin

Combining Mass Spectrometry and Toxicology for a Multi-Country European Epidemiologic Study on Drinking Water Disinfection By-Products

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The HiWATE (Health Impacts of long-term exposure to disinfection by-products in drinking WATEr) project is the first systematic analysis that combines the epidemiology on adverse pregnancy outcomes with analytical chemistry and analytical biology in the European Union. This study...

Determination of the minor disinfection by-products formed in the water plant of Sant Joan Despi (Barcelona, Spain); Determinacion de los subproductos de desinfeccion minoritarios formados en la planta de Sant Joan Despi (Barcelona)

Energy Technology Data Exchange (ETDEWEB)

Cancho, B.; Galceran, M.T. [Universitat de Barcelona (Spain); Ventura, F. [AGBAR. Societat General d` Aigues de Barcelona, S.A. (Spain)

1997-09-01

Chlorine is widely used in drinking water disinfection due to be a powerful and not expense disinfection. Although the benefits of disinfection, the formation of stable disinfection by-products of the health concern, is the result of the interaction of aqueous chlorine with natural organic matter presents in water. Disinfection by-products generated in major concentration are trihalomethane and haloacetic acids. Disinfection by-products generated in minor concentration are haloacetonitriles, haloketones,chloral hydrate and chloropicrin and some new groups such as cyanogen halides and trihaloacetaldydes. In this work two analytical methods.: headspace/gas chromatography/electron capture detector and liquid-liquid microextraction/gas chromatography/electron capture detector are studied and compared to determine the minor by-products and to establish finally, a systematic control of them in the different stages of the Water Treatment Plant of San Joan Despi (Barcelona, Spain). (Author) 12 refs.

Drinking Water Disinfection By-products, Genetic Polymorphisms, and Birth Outcomes in a European Mother-Child Cohort Study.

Science.gov (United States)

Kogevinas, Manolis; Bustamante, Mariona; Gracia-Lavedán, Esther; Ballester, Ferran; Cordier, Sylvaine; Costet, Nathalie; Espinosa, Ana; Grazuleviciene, Regina; Danileviciute, Asta; Ibarluzea, Jesus; Karadanelli, Maria; Krasner, Stuart; Patelarou, Evridiki; Stephanou, Euripides; Tardón, Adonina; Toledano, Mireille B; Wright, John; Villanueva, Cristina M; Nieuwenhuijsen, Mark

2016-11-01

We examined the association between exposure during pregnancy to trihalomethanes, the most common water disinfection by-products, and birth outcomes in a European cohort study (Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water). We took into account exposure through different water uses, measures of water toxicity, and genetic susceptibility. We enrolled 14,005 mothers (2002-2010) and their children from France, Greece, Lithuania, Spain, and the UK. Information on lifestyle- and water-related activities was recorded. We ascertained residential concentrations of trihalomethanes through regulatory records and ad hoc sampling campaigns and estimated route-specific trihalomethane uptake by trimester and for whole pregnancy. We examined single nucleotide polymorphisms and copy number variants in disinfection by-product metabolizing genes in nested case-control studies. Average levels of trihalomethanes ranged from around 10 μg/L to above the regulatory limits in the EU of 100 μg/L between centers. There was no association between birth weight and total trihalomethane exposure during pregnancy (β = 2.2 g in birth weight per 10 μg/L of trihalomethane, 95% confidence interval = 3.3, 7.6). Birth weight was not associated with exposure through different routes or with specific trihalomethane species. Exposure to trihalomethanes was not associated with low birth weight (odds ratio [OR] per 10 μg/L = 1.02, 95% confidence interval = 0.95, 1.10), small-for-gestational age (OR = 0.99, 0.94, 1.03) and preterm births (OR = 0.98, 0.9, 1.05). We found no gene-environment interactions for mother or child polymorphisms in relation to preterm birth or small-for-gestational age. In this large European study, we found no association between birth outcomes and trihalomethane exposures during pregnancy in the total population or in potentially genetically susceptible subgroups. (See video abstract at http://links.lww.com/EDE/B104.).

Effect of peracetic acid, ultraviolet radiation, nanofiltration-chlorine in the disinfection of a non conventional source of water (Tula Valley).

Science.gov (United States)

Trujillo, J; Barrios, J A; Jimenez, B

2008-01-01

Water supply for human consumption requires certain quality that reduces health risks to consumers. In this sense, the process of disinfection plays an important role in the elimination of pathogenic microorganisms. Even though chlorination is the most applied process based on its effectiveness and cost, its application is being questioned considering the formation of disinfection by-products (DBPs). Therefore, alternative disinfectants are being evaluated and some treatment processes have been proposed to remove DBPs precursors (organic matter. This paper reports the results of disinfection of a non conventional source of water (aquifer recharged unintentionally with raw wastewater) with peracetic acid (PAA) and ultraviolet radiation (UV) as well as nanofiltration (NF) followed by chlorination to produce safe drinking water. The results showed that a dose of 2 mg/L PAA was needed to eliminate total and faecal coliforms. For UV light, a dose of 12.40 mWs/cm2 reduced total and faecal coliforms below the detection limit. On the other hand, chlorine demand of water before NF was 1.1-1.3 mg/L with a trihalomethane formation potential (THMFP) of 118.62 microg/L, in contrast with chlorination after NF where the demand was 0.5 mg/L and THMFP of 17.64 microg/L. The recommended scheme is nanofiltration + chlorination.

Biological Treatment of Water Disinfection Byproducts using ...

Science.gov (United States)

Major disinfection by-products (DBPs) from the chlorination process of drinking water include trihalomethanes (THMs) and haloacetic acides (HAA5). THMs mainly consist of chloroform, and other harsh chemicals. Prolonged consumptions of drinking water containing high levels of THMs has been linked with diseases of the liver, kidneys, bladder, or central nervous system and may increase likelihood of cancer. A risk also exists for THMs exposure via inhalation while showering, bathing or washing clothes and dishes. Due to these risks, the U.S. EPA regulate THMs content in drinking water. This research investigates biological degradation of THM using chloroform as a model compound. The study aims to decrease possible risks of THMs through filtration. Throughout this year’s presentations, there is a common theme of health and safety concerns. UC researchers are working hard to clean water ways of naturally occurring contaminates as well as man-made toxins found in our waterways. The significance of these presentations translates into the promise of safer environments, and more importantly saved lives, as UC’s faculty continues to produce real-world solutions to problems threatening the world around us. A biotech process has been developed and demonstrated that effectively remove and treat volatile disinfection by-products from drinking water. The process strips low concentration disinfection by-products, such as trihalomethanes, that are formed during the chlori

Induction of Antimicrobial Resistance in Escherichia coli and Non-Typhoidal Salmonella Strains after Adaptation to Disinfectant Commonly Used on Farms in Vietnam

Directory of Open Access Journals (Sweden)

Nguyen T. Nhung

2015-10-01

Full Text Available In Vietnam, commercial disinfectants containing quaternary ammonium compounds (QACs are commonly used in pig and poultry farms to maintain hygiene during production. We hypothesized that sustained exposure to sub-bactericidal concentrations of QAC-based disinfectants may result in increased levels of antimicrobial resistance (AMR among Enterobacteriacea due to the increase of efflux pump expression. To test this hypothesis we exposed six antimicrobial-susceptible Escherichia coli (E. coli and six antimicrobial-susceptible non-typhoidal Salmonella (NTS isolates to increasing concentrations of a commonly used commercial disinfectant containing a mix of benzalkonium chloride and glutaraldehyde. Over the 12-day experiment, strains exhibited a significant change in their minimum inhibitory concentration (MIC of the disinfectant product (mean increase of 31% (SD ± 40 (p = 0.02, paired Wilcoxon test. Increases in MIC for the disinfectant product were strongly correlated with increases in MIC (or decreases in inhibition zone for all antimicrobials (Pearson’s correlation coefficient 0.71–0.83, all p < 0.01. The greatest increases in MIC (or decreases in inhibition zone were observed for ampicillin, tetracycline, ciprofloxacin, and chloramphenicol, and the smallest for gentamicin, trimethoprim/sulphamethoxazole. The treatment of 155 representative E. coli isolates from farmed and wild animals in the Mekong Delta (Vietnam with phenyl-arginine beta-naphthylamide (PAβN, a generic efflux pump inhibitor, resulted in reductions in the prevalence of AMR ranging from 0.7% to 3.3% in these organisms, indicating a small contribution of efflux pumps on the observed prevalence of AMR on farms. These results suggest that the mass usage of commercial disinfectants, many of which contain QACs, is potentially a contributing factor on the generation and maintenance of AMR in animal production in Vietnam.

THE OCCURRENCE OF DISINFECTION BY-PRODUCTS OF HEALTH CONCERN IN DRINKING WATER: RESULTS OF A NATIONWIDE DBP OCCURRENCE STUDY

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The motivation for this Nationwide Disinfection By-product (DBP) Occurrence Study was two-fold: First, more than 500 DBPs have been reported in the literature, yet there is almost no quantitative occurrence information for most. As a result, there is significant uncertainty ove...

Predictive model for disinfection by-product in Alexandria drinking water, northern west of Egypt.

Science.gov (United States)

Abdullah, Ali M; Hussona, Salah El-dien

2013-10-01

Chlorine has been utilized in the early stages of water treatment processes as disinfectant. Disinfection for drinking water reduces the risk of pathogenic infection but may pose a chemical threat to human health due to disinfection residues and their by-products (DBP) when the organic and inorganic precursors are present in water. In the last two decades, many modeling attempts have been made to predict the occurrence of DBP in drinking water. Models have been developed based on data generated in laboratory-scale and field-scale investigations. The objective of this paper is to develop a predictive model for DBP formation in the Alexandria governorate located at the northern west of Egypt based on field-scale investigations as well as laboratory-controlled experimentations. The present study showed that the correlation coefficient between trihalomethanes (THM) predicted and THM measured was R (2)=0.88 and the minimum deviation percentage between THM predicted and THM measured was 0.8 %, the maximum deviation percentage was 89.3 %, and the average deviation was 17.8 %, while the correlation coefficient between dichloroacetic acid (DCAA) predicted and DCAA measured was R (2)=0.98 and the minimum deviation percentage between DCAA predicted and DCAA measured was 1.3 %, the maximum deviation percentage was 47.2 %, and the average deviation was 16.6 %. In addition, the correlation coefficient between trichloroacetic acid (TCAA) predicted and TCAA measured was R (2)=0.98 and the minimum deviation percentage between TCAA predicted and TCAA measured was 4.9 %, the maximum deviation percentage was 43.0 %, and the average deviation was 16.0 %.

Associations Between Disinfection By-Product Exposures and Craniofacial Birth Defects.

Science.gov (United States)

Kaufman, John A; Wright, J Michael; Evans, Amanda; Rivera-Núñez, Zorimar; Meyer, Amy; Narotsky, Michael G

2018-02-01

The aim of this study was to examine associations between craniofacial birth defects (CFDs) and disinfection by-product (DBP) exposures, including the sum of four trihalomethanes (THM4) and five haloacetic acids (HAA5) (ie, DBP9). We calculated first trimester adjusted odds ratios (aORs) for different DBPs in a matched case-control study of 366 CFD cases in Massachusetts towns with complete 1999 to 2004 THM and HAA data. We detected elevated aORs for cleft palate with DBP9 (highest quintile aOR = 3.52; 95% CI: 1.07, 11.60), HAA5, trichloroacetic acid (TCAA), and dichloroacetic acid. We detected elevated aORs for eye defects with TCAA and chloroform. This is the first epidemiological study of DBPs to examine eye and ear defects, as well as HAAs and CFDs. The associations for cleft palate and eye defects highlight the importance of examining specific defects and DBPs beyond THM4.

Evaluating the Sporicidal Activity of Disinfectants against Clostridium difficile and Bacillus amyloliquefaciens Spores by Using the Improved Methods Based on ASTM E2197-11.

Science.gov (United States)

Uwamahoro, Marie Christine; Massicotte, Richard; Hurtubise, Yves; Gagné-Bourque, François; Mafu, Akier Assanta; Yahia, L'Hocine

2018-01-01

Spore-forming pathogenic bacteria, such as Clostridium difficile , are associated with nosocomial infection, leading to the increased use of sporicidal disinfectants, which impacts socioeconomic costs. However, C. difficile can be prevented using microorganisms such as Bacillus amyloliquefaciens , a prophylactic agent that has been proven to be effective against it in recent tests or it can be controlled by sporicidal disinfectants. These disinfectants against spores should be evaluated according to a known and recommended standard. Unfortunately, some newly manufactured disinfectants like Bioxy products have not yet been tested. ASTM E2197-11 is a standard test that uses stainless steel disks (1 cm in diameter) as carriers, and the performance of the test formulation is calculated by comparing the number of viable test organisms to that on the control carriers. Surface tests are preferable for evaluating disinfectants with sporicidal effects on hard surfaces. This study applies improved methods, based on the ASTM E2197-11 standard, for evaluating and comparing the sporicidal efficacies of several disinfectants against spores of C. difficile and B. amyloliquefaciens , which are used as the test organisms. With the improved method, all spores were recovered through vortexing and membrane filtration. The results show that chlorine-based products are effective in 5 min and Bioxy products at 5% w/v are effective in 10 min. Although Bioxy products may take longer to prove their effectiveness, their non-harmful effects to hospital surfaces and people have been well established in the literature.

Recent advances in drinking water disinfection: successes and challenges.

Science.gov (United States)

Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

2013-01-01

Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

Future directions in water quality regulations

International Nuclear Information System (INIS)

Pontius, F.W.

1997-01-01

The Safe Drinking Water Act amendments of 1996 have imposed new requirements on the US Environmental Protection Agency (USEPA) to establish drinking water regulations. The regulatory process has been revised and now requires the use of sound science. Costs, benefits, and competing risks may also be considered. Current regulations for fluoride, volatile organic chemicals, total coliforms, surface water treatment, Phase 2 and Phase 5 synthetic organic and inorganic contaminants, and lead and copper remain basically unchanged. New deadlines are established for the regulation of arsenic, sulfate, radon, disinfectants and disinfection by-products, enhanced surface water treatment, and groundwater disinfection

Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

Directory of Open Access Journals (Sweden)

Sophie Smither

2016-07-01

Full Text Available The West Africa Ebola virus (EBOV outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO2) and their by-products hydrogen peroxide (H2O2) and chlorite (ClO2-)

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar; Baun, Anders; Andersen, Henrik Rasmus

2017-01-01

Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should......: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO2) as well as two by-products of their use: hydrogen peroxide (H2O2) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC50 values ranged from 0.16 to 2.9 mg...

Evaluation of associations between lifetime exposure to drinking water disinfection by-products and bladder cancer in dogs.

Science.gov (United States)

Backer, Lorraine C; Coss, Angela M; Wolkin, Amy F; Flanders, W Dana; Reif, John S

2008-06-01

To assess the risk of bladder cancer in dogs from exposure to drinking water disinfection by-products and determine whether dogs could serve as sentinels for human bladder cancer associated with such exposures. Case-control study. 100 dogs with cancer of the urinary bladder and 100 control dogs. Case and control dogs were frequency-matched by age (within 2 years) and sex. Owners of dogs enrolled provided verbal informed consent and were interviewed by telephone. The telephone questionnaire included a complete residence history for each dog. Each dog's total exposure history to trihalomethanes was reconstructed from its residence history and corresponding drinking water utility company data. No association was detected between increasing years of exposure to chlorinated drinking water and risk of bladder cancer. Dogs with bladder cancer were exposed to higher total trihalomethanes concentrations than control dogs; however, the difference was not significant. Although humans and their dogs live in the same household, the activity patterns of dogs may lead to lower exposures to household tap water. Thus, although exposure to disinfection by-products in tap water may be a risk factor for human bladder cancer, this may not be true for canine bladder cancer at the concentrations at which dogs are exposed.

Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

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N. Kenters

2017-06-01

Full Text Available Abstract Background In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested for their efficacy against spores of distinctive C. difficile PCR ribotypes. Methods Four different products were tested; 1 hydrogen peroxide 1.5%; 2 glucoprotamin 1.5%; 3 a mixture of ethanol, propane and N-alkyl amino propyl glycine; and 4 a mixture of didecyldimonium chloride, benzalkonium chloride, polyaminopropyl, biguanide and dimenthicone as active ingredients. Tiles were contaminated with a test solution containing a concentration of 5x106CFU/ml spores of C. difficile strains belonging to PCR ribotypes 010, 014 or 027. The tiles were left to dry for an hour and then wiped or sprayed with one of the sprays or wipes as intended by the manufacturers. When products neutralized after 5 min, microbiological cultures and ATP measures were performed. Results Irrespective of the disinfection method, the microbial count log10 reduction of C. difficile PCR ribotype 010 was highest, followed by the reduction of C. difficile 014 and C. difficile 027. Overall, the wipes performed better than the sprays with the same active ingredient. On average, although not significantly, a difference in relative light units (RLU reduction between the wipes and sprays was found. The wipes had a higher RLU log10 reduction, but no significant difference for RLU reduction was observed between the different C. difficile strains (p = 0.16. Conclusion C. difficile spores of PCR ribotypes 014 and 027 strains are more difficult to eradicate than non-toxigenic PCR ribotype 010. In general, impregnated cleaning/disinfection wipes performed better than ready-to-use sprays. Wipes with hydrogen peroxide (1.5% showed the highest bactericidal activity.

The Effect of Disinfection by Spray Atomization on Dimensional Accuracy of Condensation Silicone Impressions

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Fariba Saleh Saber

2010-12-01

Full Text Available Background and aims. The condensation silicone impression materials are available, but there is little knowledge of their accuracy after disinfection. The objective of this study was to evaluate the effect of the disinfection by spray atomization on dimensional accuracy of condensation silicone impressions. Materials and methods. Impressions were made on a stainless steel master model containing a simulated two complete crown preparation with an edentulous space interposed using Spidex® and Rapid® impression materials. 44 impressions were made with each material, of which 16 were disinfected with 5.25% sodium hypochlorite, 16 were disinfected with 10% iodophor and 12 were not disinfected. Three dimensional measurements of working casts, including interpreparation distance, height, and diameter, were calculated using a measuring microscope graduated at 0.001 mm. Dimensional changes (mm between the disinfected and non-disinfected working casts were compared. One-way analysis of variance (ANOVA was employed to analyze the data (α=0.05. Results. Disinfection of each condensation silicone material by spraying atomization with two different disinfectant material resulted in significant change in interpreparation distance (p<0.05. Changes in height and diameter were only significant in Spidex® impressions (p<0.05. Conclusion. Significant changes in the mean dimensions were seen as a result of disinfection by spraying; however, the dimensional changes do not seem great enough to cause critical positional distortion of teeth when fixed partial denture restorations are made.

Bioanalytical assessment of adaptive stress responses in drinking water: A predictive tool to differentiate between micropollutants and disinfection by-products.

Science.gov (United States)

Hebert, Armelle; Feliers, Cedric; Lecarpentier, Caroline; Neale, Peta A; Schlichting, Rita; Thibert, Sylvie; Escher, Beate I

2018-04-01

Drinking water can contain low levels of micropollutants, as well as disinfection by-products (DBPs) that form from the reaction of disinfectants with organic and inorganic matter in water. Due to the complex mixture of trace chemicals in drinking water, targeted chemical analysis alone is not sufficient for monitoring. The current study aimed to apply in vitro bioassays indicative of adaptive stress responses to monitor the toxicological profiles and the formation of DBPs in three drinking water distribution systems in France. Bioanalysis was complemented with chemical analysis of forty DBPs. All water samples were active in the oxidative stress response assay, but only after considerable sample enrichment. As both micropollutants in source water and DBPs formed during treatment can contribute to the effect, the bioanalytical equivalent concentration (BEQ) approach was applied for the first time to determine the contribution of DBPs, with DBPs found to contribute between 17 and 58% of the oxidative stress response. Further, the BEQ approach was also used to assess the contribution of volatile DBPs to the observed effect, with detected volatile DBPs found to have only a minor contribution as compared to the measured effects of the non-volatile chemicals enriched by solid-phase extraction. The observed effects in the distribution systems were below any level of concern, quantifiable only at high enrichment and not different from bottled mineral water. Integrating bioanalytical tools and the BEQ mixture model for monitoring drinking water quality is an additional assurance that chemical monitoring is not overlooking any unknown chemicals or transformation products and can help to ensure chemically safe drinking water. Copyright © 2017. Published by Elsevier Ltd.

Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products

Science.gov (United States)

Hrudey, Steve E.; Backer, Lorraine C.; Humpage, Andrew R.; Krasner, Stuart W.; Michaud, Dominique S.; Moore, Lee E.; Singer, Philip C.; Stanford, Benjamin D.

2015-01-01

Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches. PMID:26309063

Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products.

Science.gov (United States)

Hrudey, Steve E; Backer, Lorraine C; Humpage, Andrew R; Krasner, Stuart W; Michaud, Dominique S; Moore, Lee E; Singer, Philip C; Stanford, Benjamin D

2015-01-01

Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches.

Drinking water disinfection by means of ultraviolet radiation. Desinfektion von Trinkwasser durch UV-Bestrahlung

Energy Technology Data Exchange (ETDEWEB)

Gelzhaeuser, P; Bewig, F; Holm, K; Kryschi, R; Reich, G; Steuer, W

1985-01-01

The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice.

Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

OpenAIRE

Sattar, S. A.; Springthorpe, V. S.; Karim, Y.; Loro, P.

1989-01-01

The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were...

In vitro evaluation of the susceptibility of Acinetobacter baumannii isolates to antiseptics and disinfectants: comparison between clinical and environmental isolates

Directory of Open Access Journals (Sweden)

Sanae Lanjri

2017-04-01

Full Text Available Abstract Background This study aims to assess the susceptibility of Acinetobacter baumannii isolates to the antiseptics and disinfectants commonly used, and to the non-approved product. Methods This is a prospective study carried out from February to August 2015, in the Bacteriology department of Mohammed V Military Teaching hospital of Rabat on A.baumannii isolates collected from colonized and/or infected patients and environmental samples. The antiseptics and disinfectants susceptibility testing was assessed using the micromethod validated in our department. The antiseptics and disinfectants studied were: 70% ethyl alcohol, chlorhexidine, povidone-iodine, didecyldimethylammonium chloride and a commercial product which was presented as a hospital disinfectant (non-registered product. Results Povidone-iodine, 0.5% chlorhexidine digluconate, 70% ethyl alcohol and didecyl dimethyl ammonium chloride in combination with N- (3-aminopropyl -N-dodecylpropane-1, 3-diamine were effective against all the 81 A.baumannii isolates tested, and their logarithmic reduction ≥ 5 were observed in 100% of the isolates in their undiluted form. The strains isolated from patients were more resistant than environmental strains: at a dilution of ½ for 70% ethyl alcohol (37.77% vs 11.11%, p = 0.007 and at a dilution of 1/10 (100% vs 69.44%, p < 0.001 for povidone iodine. The non-registered product was ineffective with a resistance rate of 96.29% at a dilution of 1/50, 45.67% at a dilution of 1/10 and 13.58% in its purest form. Conclusion Our study revealed the effectiveness of the main disinfectants and antiseptics used in Morocco; three antiseptics tested were effective in their purest form against the 81 A.baumannii isolates. Regarding disinfectants, our results showed an efficacy of didecyl dimethyl ammonium at the recommended use concentration and in its purest form. This study emphasizes the need for using disinfectants and antiseptics in dilutions

A review on wastewater disinfection

Directory of Open Access Journals (Sweden)

Mohammad Mehdi Amin

2013-01-01

Full Text Available Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent disinfection. Understanding the differences in inactivation mechanisms is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies. Disinfection byproducts discharged from wastewater treatment plants may impair aquatic ecosystems and downstream drinking-water quality. Numerous inorganic and organic micropollutants can undergo reactions with disinfectants. Therefore, to mitigate the adverse effects and also to enhance that efficiency, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. This review gives a summary of the traditional, innovative, and combined disinfection alternatives and also disinfection byproducts for effluent of municipal wastewater treatment plants.

Sensitivity to disinfection of bacterial indicator organisms for monitoring the Salmonella Enteritidis status of layer farms after cleaning and disinfection.

Science.gov (United States)

Dewaele, I; Ducatelle, R; Herman, L; Heyndrickx, M; De Reu, K

2011-06-01

The present study evaluated Escherichia coli, Enterococcus faecalis, and Enterococcus hirae as potential indicator organisms for the possible Salmonella Enteritidis (SE) presence in layer farms after cleaning and disinfection by comparing their susceptibility to disinfection. A quantitative suspension disinfection test according to European Standard EN1656 was performed using disinfection products CID20 and Virocid (both from CID Lines, Ieper, Belgium). In a preliminary test, the sensitivity to both disinfection products was compared between ATCC strains of SE, E. coli, En. faecalis, and En. hirae. The sensitivity of SE to disinfection was most comparable to that of E. coli. A second disinfection test compared the elimination of E. coli to SE ATCC strains as well as field strains. Results showed no significant effect regarding the strain (P > 0.05 for CID20 and Virocid), meaning that no difference was detected in sensitivity toward disinfection. When comparing the sensitivity in general at species level for all concentrations of disinfectant used, no significant difference was found between E. coli and SE in sensitivity to Virocid (P > 0.05). In conclusion, because of its similar response to disinfection in a suspension disinfection test, E. coli could be used as an indicator for possible Salmonella presence after cleaning and disinfection.

Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse

International Nuclear Information System (INIS)

Yoon, C.G.; Jung, K.W.; Ham, J.H.; Jeon, J.H.

2003-01-01

Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration of 10~30 MPN/100mL increased to the level of 100 MPN/100mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time

[Control of disinfection in buildings used for poultry raising].

Science.gov (United States)

Maris, P

1989-01-01

During a 2-year survey in turkey breeding farms, it was possible to compare six disinfection procedures by monitoring 14 first disinfections following the breeding house cleaning and 14 second disinfections prior to animal return. By swabbing all the germs from asbestos concrete surfaces, we noted that in the case of first disinfection the chloramine T-based product was more effective than phenol or quaternary ammonium-aldehyde-based products. For the second disinfection, it was demonstrated that a minimal dose of 15 kg of formaldehyde was necessary for disinfection to be satisfactory; 12 to 15 kg paraformaldehyde was as effective as 40 to 60 liters of 30-35% formol for buildings, the ground surface of which covered between 1,000 and 1,300 m2.

Ultraviolet disinfection of potable water

Energy Technology Data Exchange (ETDEWEB)

Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

1990-06-15

Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

Ultraviolet disinfection of potable water

International Nuclear Information System (INIS)

Wolfe, R.L.

1990-01-01

Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

Study and application of herbal disinfectants in China.

Science.gov (United States)

Chen, Zhao-Bin

2004-12-01

Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice.

Removal of soluble microbial products as the precursors of disinfection by-products in drinking water supplies.

Science.gov (United States)

Liu, Jin-Lin; Li, Xiao-Yan

2015-01-01

Water pollution worsens the problem of disinfection by-products (DBPs) in drinking water supply. Biodegradation of wastewater organics produces soluble microbial products (SMPs), which can be important DBP precursors. In this laboratory study, a number of enhanced water treatment methods for DBP control, including enhanced coagulation, ozonation, and activated carbon adsorption, were evaluated for their effectiveness in treating SMP-containing water for the DBP reduction purpose. The results show that enhanced coagulation with alum could remove SMPs only marginally and decrease the DBP formation potential (DBPFP) of the water by less than 20%. Although ozone could cause destruction of SMPs in water, the overall DBPFP of the water did not decrease but increased after ozonation. In contrast, adsorption by granular activated carbon could remove the SMP organics from water by more than 60% and reduce the DBPFP by more than 70%. It is apparent that enhanced coagulation and ozonation are not suitable for the removal of SMPs as DBP precursors from polluted water, although enhanced coagulation has been commonly used to reduce the DBP formation caused by natural organic matter. In comparison, activated carbon adsorption is shown as a more effective means to remove the SMP content from water and hence to control the wastewater-derived DBP problem in water supply.

Disinfection By-Product Exposures and the Risk of Specific Cardiac Birth Defects

Science.gov (United States)

Wright, J. Michael; Evans, Amanda; Kaufman, John A.; Rivera-Núñez, Zorimar; Narotsky, Michael G.

2016-01-01

Background: Epidemiological studies suggest that women exposed to disinfection by-products (DBPs) have an increased risk of delivering babies with cardiovascular defects (CVDs). Objective: We examined nine CVDs in relation to categorical DBP exposures including bromoform, chloroform, dibromochloromethane (DBCM), bromodichloromethane (BDCM), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and summary DBP measures (HAA5, THMBr, THM4, and DBP9). Methods: We calculated adjusted odds ratios (aORs) in a case–control study of birth defects in Massachusetts with complete quarterly 1999–2004 trihalomethane (THM) and haloacetic acid (HAA) data. We randomly matched 10 controls each to 904 CVD cases based on week of conception. Weight-averaged aggregate first-trimester DBP exposures were assigned to individuals based on residence at birth. Results: We detected associations for tetralogy of Fallot and the upper exposure categories for TCAA, DCAA, and HAA5 (aOR range, 3.34–6.51) including positive exposure–response relationships for DCAA and HAA5. aORs consistent in magnitude were detected between atrial septal defects and bromoform (aOR = 1.56; 95% CI: 1.01, 2.43), as well as DBCM, chloroform, and THM4 (aOR range, 1.26–1.67). Ventricular septal defects (VSDs) were associated with the highest bromoform (aOR = 1.85; 95% CI: 1.20, 2.83), MBAA (aOR = 1.81; 95% CI: 0.85, 3.84), and DBCM (aOR = 1.54; 95% CI: 1.00, 2.37) exposure categories. Conclusions: To our knowledge, this is the first birth defect study to develop multi-DBP adjusted regression models as well as the first CVD study to evaluate HAA exposures and the second to evaluate bromoform exposures. Our findings, therefore, inform exposure specificity for the consistent associations previously reported between THM4 and CVDs including VSDs. Citation: Wright JM, Evans A, Kaufman JA, Rivera-Núñez Z, Narotsky MG. 2017. Disinfection by-product exposures and the risk of specific

Risk of viral acute gastrointestinal illness from non-disinfected drinking water distribution systems

Science.gov (United States)

Acute gastrointestinal illness (AGI) resulting from pathogens directly entering the piping of drinking water distribution systems is insufficiently understood. Here, we estimate AGI incidence attributable to virus intrusions into non-disinfecting municipal distribution systems. Viruses were enumerat...

UV disinfection for reuse applications in North America.

Science.gov (United States)

Sakamoto, G; Schwartzel, D; Tomowich, D

2001-01-01

In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications. Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation. Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies. The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion. During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD. California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years. To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations. Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application. As a rule, the resulting effluents have low turbidity and suspended solids. For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse. This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

Basic substances under EC 1107/2009 phytochemical regulation: experience with non-biocide and food products as biorationals

Directory of Open Access Journals (Sweden)

Marchand Patrice A.

2016-07-01

Full Text Available Basic Substances are a newly effective category of Plant Protection Product under EC Regulation No 1107/2009. The first approved application of Equisetum arvense L. opened Part C of Implementing Regulation (EU No 540/2011, which lists the basic substance approved. Although E. arvense was described as a fungicide extract, subsequent applications like chitosan were related to non-biocide molecules. Consequently, plant protection product data were collected from research on alternative or traditional crop protection methods. They are notably issued or derived from foodstuffs (plants, plant by-products, plant derived products, substances and derived substances from animal origin. Applications are currently submitted by our Institute, under evaluation at different stages of the approval process or already approved. Remarkably, this Basic Substance category under pesticide EU Regulation was surprisingly designed for these non-biocidal plant protection products. In fact, components described as the “active substance” of most of the actual applications are food products like sugars and lecithin. Basic Substance applications for these foodstuffs are therefore a straightforward way of easily gaining approval for them. Here we describe the approval context and detail the agricultural uses of theses food products as Biological Control Agents (BCAs or biorationals for crop protection. From all deposited or approved Basic Substance Application (BSA, a proof has been provided that non-biocide and food products via physical barrier or lure effects may be effective plant protection products with an acceptable low profile of concern for public and agricultural safety.

Optical monitoring of Disinfection By-product Precursors with Fluorescence Excitation-Emission Mapping (F-EEM): Practical Application Issues for Drinking, Waste and Reuse Water Industry

Science.gov (United States)

Gilmore, A. M.

2012-12-01

Drinking water, wastewater and reuse plants must deal with regulations associated with bacterial contamination and halogen disinfection procedures that can generate harmful disinfection by-products (DBPs) including trihalomethanes (THMs), haloacetic acids (HOAAs) and other compounds. The natural fluorescent chromophoric dissolved organic matter (CDOM) is regulated as the major DBP precursor. This study outlines the advantages and current limitations associated with optical monitoring of water treatment processes using tcontemporary Fluorescence Excitation-Emission Mapping (F-EEM). The F-EEM method coupled with practical peak indexing and multi-variate analyses is potentially superior in terms of cost, speed and sensitivity over conventional total organic carbon (TOC) meters and specific UV-absorbance (SUVA) measurements. Hence there is strong interest in developing revised environmental regulations around the F-EEM technique instruments which can incidentally simultaneously measure the SUVA and DOC parameters. Importantly, the F-EEM technique, compared to the single-point TOC and SUVA signals can resolve CDOM classes distinguishing those that strongly cause DBPs. The F-EEM DBP prediction method can be applied to surface water sources to evaluate DBP potential as a function of the point sources and reservoir depth profiles. It can also be applied in-line to rapidly adjust DOC removal processes including sedimentation-flocculation, microfiltration, reverse-osmosis, and ozonation. Limitations and interferences for F-EEMs are discussed including those common to SUVA and TOC in contrast to the advantages including that F-EEMs are less prone to interferences from inorganic carbon and metal contaminations and require little if any chemical preparation. In conclusion, the F-EEM method is discussed in terms of not only the DBP problem but also as a means of predicting (concurrent to DBP monitoring) organic membrane fouling in water-reuse and desalination plants.

Modelling formation of disinfection by-products in water distribution: Optimisation using a multi-objective evolutionary algorithm

KAUST Repository

Radhakrishnan, Mohanasundar; Pathirana, Assela; Ghebremichael, Kebreab A.; Amy, Gary L.

2012-01-01

Concerns have been raised regarding disinfection by-products (DBPs) formed as a result of the reaction of halogen-based disinfectants with DBP precursors. In order to appreciate the chemical and biological tradeoffs, it is imperative to understand the formation trends of DBPs and their spread in the distribution network. However, the water at a point in a complex distribution system is a mixture from various sources, whose proportions are complex to estimate and requires advanced hydraulic analysis. To understand the risks of DBPs and to develop mitigation strategies, it is important to understand the distribution of DBPs in a water network, which requires modelling. The goal of this research was to integrate a steady-state water network model with a particle backtracking algorithm and chlorination as well as DBPs models in order to assess the tradeoffs between biological and chemical risks in the distribution network. A multi-objective optimisation algorithm was used to identify the optimal proportion of water from various sources, dosages of alum, and dosages of chlorine in the treatment plant and in booster locations to control the formation of chlorination DBPs and to achieve a balance between microbial and chemical risks. © IWA Publishing 2012.

Modelling formation of disinfection by-products in water distribution: Optimisation using a multi-objective evolutionary algorithm

KAUST Repository

Radhakrishnan, Mohanasundar

2012-05-01

Concerns have been raised regarding disinfection by-products (DBPs) formed as a result of the reaction of halogen-based disinfectants with DBP precursors. In order to appreciate the chemical and biological tradeoffs, it is imperative to understand the formation trends of DBPs and their spread in the distribution network. However, the water at a point in a complex distribution system is a mixture from various sources, whose proportions are complex to estimate and requires advanced hydraulic analysis. To understand the risks of DBPs and to develop mitigation strategies, it is important to understand the distribution of DBPs in a water network, which requires modelling. The goal of this research was to integrate a steady-state water network model with a particle backtracking algorithm and chlorination as well as DBPs models in order to assess the tradeoffs between biological and chemical risks in the distribution network. A multi-objective optimisation algorithm was used to identify the optimal proportion of water from various sources, dosages of alum, and dosages of chlorine in the treatment plant and in booster locations to control the formation of chlorination DBPs and to achieve a balance between microbial and chemical risks. © IWA Publishing 2012.

Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

Energy Technology Data Exchange (ETDEWEB)

Naddeo, V., E-mail: vnaddeo@unisa.it [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Landi, M.; Belgiorno, V. [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Napoli, R.M.A. [Department of Environmental Science, University of Napoli Parthenope, Via Amm. F. Acton, 38, 80133 Napoli (Italy)

2009-09-15

Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

International Nuclear Information System (INIS)

Naddeo, V.; Landi, M.; Belgiorno, V.; Napoli, R.M.A.

2009-01-01

Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

Ingested Nitrate, Disinfection By-products, and Kidney Cancer Risk in Older Women.

Science.gov (United States)

Jones, Rena R; Weyer, Peter J; DellaValle, Curt T; Robien, Kim; Cantor, Kenneth P; Krasner, Stuart; Beane Freeman, Laura E; Ward, Mary H

2017-09-01

N-nitroso compounds formed endogenously after nitrate/nitrite ingestion are animal renal carcinogens. Previous epidemiologic studies of drinking water nitrate did not evaluate other potentially toxic water contaminants, including the suspected renal carcinogen chloroform. In a cohort of postmenopausal women in Iowa (1986-2010), we used historical measurements to estimate long-term average concentrations of nitrate-nitrogen (NO3-N) and disinfection by-products (DBP) in public water supplies. For NO3-N and the regulated DBP (total trihalomethanes [THM] and the sum of five haloacetic acids [HAA5]), we estimated the number of years of exposure above one-half the current maximum contaminant level (>½-MCL NO3-N; >5 mg/L). Dietary intakes were assessed via food frequency questionnaire. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox models, and evaluated interactions with factors influencing N-nitroso compound formation. We identified 125 incident kidney cancers among 15,577 women reporting using water from public supplies >10 years. In multivariable models, risk was higher in the 95th percentile of average NO3-N (HRp95vsQ1 = 2.3; CI: 1.2, 4.3; Ptrend = 0.33) and for any years of exposure >½-MCL; adjustment for total THM did not materially change these associations. There were no independent relationships with total THM, individual THMs chloroform and bromodichloromethane, or with haloacetic acids. Dietary analyses yielded associations with high nitrite intake from processed meats but not nitrate or nitrite overall. We found no interactions. Relatively high nitrate levels in public water supplies were associated with increased risk of renal cancer. Our results also suggest that nitrite from processed meat is a renal cancer risk factor.

Comparison of sampling procedures and microbiological and non-microbiological parameters to evaluate cleaning and disinfection in broiler houses.

Science.gov (United States)

Luyckx, K; Dewulf, J; Van Weyenberg, S; Herman, L; Zoons, J; Vervaet, E; Heyndrickx, M; De Reu, K

2015-04-01

Cleaning and disinfection of the broiler stable environment is an essential part of farm hygiene management. Adequate cleaning and disinfection is essential for prevention and control of animal diseases and zoonoses. The goal of this study was to shed light on the dynamics of microbiological and non-microbiological parameters during the successive steps of cleaning and disinfection and to select the most suitable sampling methods and parameters to evaluate cleaning and disinfection in broiler houses. The effectiveness of cleaning and disinfection protocols was measured in six broiler houses on two farms through visual inspection, adenosine triphosphate hygiene monitoring and microbiological analyses. Samples were taken at three time points: 1) before cleaning, 2) after cleaning, and 3) after disinfection. Before cleaning and after disinfection, air samples were taken in addition to agar contact plates and swab samples taken from various sampling points for enumeration of total aerobic flora, Enterococcus spp., and Escherichia coli and the detection of E. coli and Salmonella. After cleaning, air samples, swab samples, and adenosine triphosphate swabs were taken and a visual score was also assigned for each sampling point. The mean total aerobic flora determined by swab samples decreased from 7.7±1.4 to 5.7±1.2 log CFU/625 cm2 after cleaning and to 4.2±1.6 log CFU/625 cm2 after disinfection. Agar contact plates were used as the standard for evaluating cleaning and disinfection, but in this study they were found to be less suitable than swabs for enumeration. In addition to measuring total aerobic flora, Enterococcus spp. seemed to be a better hygiene indicator to evaluate cleaning and disinfection protocols than E. coli. All stables were Salmonella negative, but the detection of its indicator organism E. coli provided additional information for evaluating cleaning and disinfection protocols. Adenosine triphosphate analyses gave additional information about the

Effect of Permanganate Preoxidation to Natural Organic Matter and Disinfection by-Products Formation Potential Removal

Science.gov (United States)

Hidayah, E. N.; Yeh, H. H.

2018-01-01

Laboratory scale experiments was conducted to examine effect of permanganate (KMnO4) peroxidation in characterizing and to remove natural organic matter (NOM) in source water. The experimental results shows that increasing permanganate dosage could decreased aromatic matter, as indicated by decreasing UV254 and SUVA value about 23% and 28%, respectively. It seems that permanganate preoxidation caused the breakdown of high molecular weight (MW) organics into low MW ones, as represented by increasing NPDOC about 10%. Further, disinfection by-products formation potential (DBPFP) in terms of trihalomethanes formation potential (THMFP) and haloacetic acid formation potential (HAAP) decreased about 15% and 23%, respectively. HAAFP removal is higher than THMFP removal and that DPBFP removal is consistent with UV254 and NPDOC removal.

Removal of disinfection by-product precursors by coagulation and an innovative suspended ion exchange process.

Science.gov (United States)

Metcalfe, David; Rockey, Chris; Jefferson, Bruce; Judd, Simon; Jarvis, Peter

2015-12-15

This investigation aimed to compare the disinfection by-product formation potentials (DBPFPs) of three UK surface waters (1 upland reservoir and 2 lowland rivers) with differing characteristics treated by (a) a full scale conventional process and (b) pilot scale processes using a novel suspended ion exchange (SIX) process and inline coagulation (ILCA) followed by ceramic membrane filtration (CMF). Liquid chromatography-organic carbon detection analysis highlighted clear differences between the organic fractions removed by coagulation and suspended ion exchange. Pretreatments which combined SIX and coagulation resulted in significant reductions in dissolved organic carbon (DOC), UV absorbance (UVA), trihalomethane and haloacetic acid formation potential (THMFP, HAAFP), in comparison with the SIX or coagulation process alone. Further experiments showed that in addition to greater overall DOC removal, the processes also reduced the concentration of brominated DBPs and selectively removed organic compounds with high DBPFP. The SIX/ILCA/CMF process resulted in additional removals of DOC, UVA, THMFP, HAAFP and brominated DBPs of 50, 62, 62, 62% and 47% respectively compared with conventional treatment. Copyright © 2015. Published by Elsevier Ltd.

Ozone reactions with indoor materials during building disinfection

DEFF Research Database (Denmark)

Poppendieck, D.; Hubbard, H.; Ward, M.

2007-01-01

, and particularly after several hours of disinfection, surface reaction resistance dominated the overall resistance to ozone deposition for nearly all materials. Total building disinfection by-products (all carbonyls) were quantified per unit area of each material for the experimental period. Paper, office...... partition, and medium density fiberboard each released greater than 38 mg m(-2) of by-products....

Formation of secondary products in water purification. ; Charactarization of chlorination by-products. Josui shori ni okeru fukuseiseibutsu. ; Enso shori ni yoru shodoku fukuseiseibutsu no seisei tokusei

Energy Technology Data Exchange (ETDEWEB)

Aizawa, T [The Inst. of Public Health, Tokyo (Japan)

1993-12-10

Chlorination of drinking water is an inevitable process for the purification of drinking water. It has been made clear that injected free chlorine reacts with organic matter in water to produce chlorinated by-products. Many of those compounds are toxic, and studies have been made on the international water quality standard. Water quality standard has been revised also in Japan. The sources of organic matter which is the cause for production of chlorinated by-products vary according to the kinds and conditions of the water source for drinking water. Removal of precursors in the original water, removal of by-products, and change in the disinfection system with alternate disinfectant for chlorine are among the measures for decreasing chlorinated by-products at water purification plants, but the first one is employed as the basis method. It is expected that more severe regulation may be imposed on the quality of the water source for drinking water, and more strict oxidation and disinfection systems is inevitable for water management based on the new water quality standard. 10 refs., 5 figs., 2 tabs.

Detection of genotoxic effects of drinking water disinfection by-products using Vicia faba bioassay.

Science.gov (United States)

Hu, Yu; Tan, Li; Zhang, Shao-Hui; Zuo, Yu-Ting; Han, Xue; Liu, Na; Lu, Wen-Qing; Liu, Ai-Lin

2017-01-01

Plant-based bioassays have gained wide use among the toxicological and/or ecotoxicological assessment procedures because of their simplicity, sensitivity, low cost, and reliability. The present study describes the use of Vicia faba (V. faba) micronucleus (MN) test and V. faba comet assay in the evaluation of the genotoxic potential of disinfection by-products (DBPs) commonly found in chlorine-disinfected drinking water. Five haloacetic acids and three halogenated acetonitriles were chosen as representatives of DBPs in this study because they are of potentially great public health risk. Results of the MN test indicated that monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), dibromoacetic acid (DBA), trichloroacetic acid (TCA), and trichloroacetonitrile (TCAN) caused a statistically significant increase in MN frequency in V. faba root tip cells. However, no genotoxic response was observed for dichloroacetonitrile (DCAN) and dibromoacetonitrile (DBAN). Results of the comet assay showed that all tested DBPs induced a statistically significant increase in genomic DNA damage to V. faba root tip cells. On considering the capacity to detect genomic damage of a different nature, we suggest that a combination of V. faba MN test and V. faba comet assay is a useful tool for the detection of genotoxic effects of DBPs. It is worthy of assessing the feasibility of using V. faba comet assay combined with V. faba MN test to screen for the genotoxic activity of chlorinated drinking water in future work.

Disinfection of contaminated water by using solar irradiation.

Science.gov (United States)

Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

2004-02-01

Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

Environmental and personal determinants of the uptake of disinfection by-products during swimming.

Science.gov (United States)

Font-Ribera, Laia; Kogevinas, Manolis; Schmalz, Christina; Zwiener, Christian; Marco, Esther; Grimalt, Joan O; Liu, Jiaqi; Zhang, Xiangru; Mitch, William; Critelli, Rossana; Naccarati, Alessio; Heederik, Dick; Spithoven, Jack; Arjona, Lourdes; de Bont, Jeroen; Gracia-Lavedan, Esther; Villanueva, Cristina M

2016-08-01

Trihalomethanes (THMs) in exhaled breath and trichloroacetic acid (TCAA) in urine are internal dose biomarkers of exposure to disinfection by-products (DBPs) in swimming pools. We assessed how these biomarkers reflect the levels of a battery of DBPs in pool water and trichloramine in air, and evaluated personal determinants. A total of 116 adults swam during 40min in a chlorinated indoor pool. We measured chloroform, bromodichloromethane, dibromochloromethane and bromoform in exhaled breath and TCAA in urine before and after swimming, trichloramine in air and several DBPs in water. Personal determinants included sex, age, body mass index (BMI), distance swum, energy expenditure, heart rate and 12 polymorphisms in GSTT1, GSTZ1 and CYP2E1 genes. Median level of exhaled total THMs and creatinine adjusted urine TCAA increased from 0.5 to 14.4µg/m(3) and from 2.5 to 5.8µmol/mol after swimming, respectively. The increase in exhaled brominated THMs was correlated with brominated THMs, haloacetic acids, haloacetonitriles, haloketones, chloramines, total organic carbon and total organic halogen in water and trichloramine in air. Such correlations were not detected for exhaled chloroform, total THMs or urine TCAA. Exhaled THM increased more in men, urine TCAA increased more in women, and both were affected by exercise intensity. Genetic variants were associated with differential increases in exposure biomarkers. Our findings suggest that, although affected by sex, physical activity and polymorphisms in key metabolizing enzymes, brominated THMs in exhaled breath could be used as a non-invasive DBP exposure biomarker in swimming pools with bromide-containing source waters. This warrants confirmation with new studies. Copyright © 2016 Elsevier Inc. All rights reserved.

ANALYTICAL METHODS FOR WATER DISINFECTION BY-PRODUCTS IN FOODS AND BEVERAGES

Science.gov (United States)

The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking waters come into contact with the human through multiple pathways. The most significant pathway is the ingestion of drinking water. However, ingestion can oc...

ANALYTICAL METHODS FOR WATER DISINFECTION BY-PRODUCTS IN FOODS AND BEVERAGES

Science.gov (United States)

The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking water comes in contact with humans through multiple pathways. In order to facilitate the investigation of human exposure to DBPs via foods and beverages, analy...

Zinc oxide nanoparticles for water disinfection

Directory of Open Access Journals (Sweden)

Emelita Asuncion S. Dimapilis

2018-03-01

Full Text Available The world faces a growing challenge for adequate clean water due to threats coming from increasing demand and decreasing supply. Although there are existing technologies for water disinfection, their limitations, particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, an essential chemical in the rubber and pharmaceutical industries, has attracted interest as antimicrobial agent. In nanoscale, zinc oxide has shown antimicrobial properties which make its potential great for various applications. This review discusses the synthesis of zinc oxide with focus on precipitation method, its antimicrobial property and the factors affecting it, disinfection mechanisms, and the potential application to water disinfection.

Aggregation of Adenovirus 2 in Source Water and Impacts on Disinfection by Chlorine

Science.gov (United States)

Cromeans, Theresa L.; Metcalfe, Maureen G.; Humphrey, Charles D.; Hill, Vincent R.

2016-01-01

It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 °C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L × time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water. PMID:26910058

Microbiological Efficacy Test Methods of Disinfectants

OpenAIRE

Şahiner, Aslı

2015-01-01

Disinfection process is required in every area where microbiological contamination and infection risk is present, especially in medical sector, food, veterinary and general common living areas hence many disinfectants and antiseptics are being produced for different purposes. Disinfectants are made up a large group of biocidal products. Depending on the chemical properties of active substances, targeted microorganisms may differ While some disinfectants are effective in a large spectrum, othe...

TIC-Tox: A preliminary discussion on identifying the forcing agents of DBP-mediated toxicity of disinfected water.

Science.gov (United States)

Plewa, Michael J; Wagner, Elizabeth D; Richardson, Susan D

2017-08-01

The disinfection of drinking water is a major public health achievement; however, an unintended consequence of disinfection is the generation of disinfection by-products (DBPs). Many of the identified DBPs exhibit in vitro and in vivo toxicity, generate a diversity of adverse biological effects, and may be hazards to the public health and the environment. Only a few DBPs are regulated by several national and international agencies and it is not clear if these regulated DBPs are the forcing agents that drive the observed toxicity and their associated health effects. In this study, we combine analytical chemical and biological data to resolve the forcing agents associated with mammalian cell cytotoxicity of drinking water samples from three cities. These data suggest that the trihalomethanes (THMs) and haloacetic acids may be a small component of the overall cytotoxicity of the organic material isolated from disinfected drinking water. Chemical classes of nitrogen-containing DBPs, such as the haloacetonitriles and haloacetamides, appear to be the major forcing agents of toxicity in these samples. These findings may have important implications for the design of epidemiological studies that primarily rely on the levels of THMs to define DBP exposure among populations. The TIC-Tox approach constitutes a beginning step in the process of identifying the forcing agents of toxicity in disinfected water. Copyright © 2017. Published by Elsevier B.V.

Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

Science.gov (United States)

Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

2007-11-01

Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.

A review on wastewater disinfection

OpenAIRE

Mohammad Mehdi Amin; Hassan Hashemi; Amir Mohammadi Bovini; Yung Tse Hung

2013-01-01

Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent d...

Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

Directory of Open Access Journals (Sweden)

Fargašová Agáta

2017-12-01

Full Text Available In this study, the phytotoxicity of disinfectants prepared on the base of sodium hypochlorite was determined. For our tests two commercial products, Savo and Dom Amor, as well as 10% NaClO solution were used. While Savo contained only NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base of NaClO are used in households for cleaning and disinfection of floors, furniture, sanitary and kitchen equipment. Savo may be used for the disinfection of drinking waters as well. Products with NaClO are also used for bacteria, algae and pathogens reduction in irrigation waters. As a subject, young seedlings of mustard Sinapis alba L. were used for the study of chronic toxicity. The observed parameters of the inhibition of roots and shoots growth, dry (DM and fresh (FM mass as well as photosynthetic pigments production (chlorophyll a, b, carotenoids and water content in the plants were determined. The results point out that Dom Amor was the most toxic for S. alba seedlings growth and the rank order of the FAC contents for both plant parts was arranged as: Dom Amor > Savo > NaClO. All disinfectants reduced the DM and FM of roots; however, they stimulated biomass production in the shoots. On the basis of the obtained results it could be concluded, that disinfectants stimulated photosynthetic pigments production and reduced water content mainly in the roots. Dom Amor did not significantly reduced the water content in the shoots and for this parameter the following rank orders of inhibition for roots and shoots could be arranged as NaClO > Dom Amor > Savo and NaClO > Savo > Dom Amor, respectively. All commercial products increased chlorophyll a (Chla and the carotenoids (Car content in the shoots. As significant increase was confirmed first for Chla whose content in the presence of NaClO at concentration 24 mL/L overextended that in the control by 3.5 times. The rank orders of stimulation for Chla and Car were NaClO > Savo > Dom Amor and Dom

Disinfection by electrohydraulic treatment.

Science.gov (United States)

Allen, M; Soike, K

1967-04-28

Electrohydraulic treatment was applied to suspensions of Escherichia coli, spores of Bacillus subtilis var. niger, Saccharomyces cerevisiae, and bacteriophage T2 at an input energy that, in most cases, was below the energy required to sterilize. The input energy was held relatively constant for each of these microorganisms, but the capacitance and voltage were varied. Data are presented which show the degree of disinfection as a function of capacitance and voltage. In all cases, the degree of disinfection for a given input energy increases as both capacitance and voltage are lowered.

MODERATING INFLUENCE OF THE DRINKING WATER DISINFECTION BY-PRODUCT DIBROMOACETIC ACID ON A DITHIOCARBAMATE-INDUCED SUPPRESSION OF THE LUTEINIZING HORMONE SURGE IN FEMALE RATS.

Science.gov (United States)

The disinfection by-product dibromoacetic acid (DBA) has been found in female rats to increase circulating concentrations of both estradiol (E2) and estrone (E1). This effect is apparently due, at least in part, to a suppression in hepatic catabolism. The present study investigat...

Disinfection of dental impressions - compliance to accepted standards.

Science.gov (United States)

Almortadi, N; Chadwick, R G

2010-12-18

The responsibility of ensuring impressions have been cleaned and disinfected before dispatch to the dental laboratory lies solely with the dentist. Uncertainty of impression disinfection risks both the health of the receiving dental technician and potential repeat disinfection of an already disinfected impression with detrimental consequences for its dimensions. To ascertain, from the perspectives of dentists and dental technicians, current impression decontamination and disinfection practices with, in the case of the technicians, an estimate of the relative prevalence of contaminated voids within apparently disinfected impressions. Anonymous postal questionnaire. Dentist (n = 200) and dental technician (n = 200) potential participants, selected at random from the registers held by the General Dental Council, were invited to complete an anonymous postal questionnaire that sought to establish current practices and perceived effectiveness of impression disinfection. Questionnaire return rates of 42.1% and 31.2% were recorded for dentists and dental technicians respectively. A wide range of solutions, at different dilutions of the same product, was used by the dentists to disinfect dental impressions. 37.2% rinsed the impressions with water, and 2.6% always brushed debris away, before disinfection. 24.7% of dentists did not inform the laboratory of disinfection. Irrespective of the disinfection status of the received impressions, 50% of the responding dental technicians disinfected all impressions. 95% of them had received blood-contaminated impressions. 15% had encountered blood-filled voids upon trimming back the peripheries of impressions. 64.7% were confident that the impressions received by them had been disinfected by the dentists. Compliance with good practice is less than ideal and education in impression disinfection for both dentists and dental technicians is required to address this.

Antimicrobial Products Registered for Disinfection Use against Avian Influenza on Poultry Farms and Other Facilities

Science.gov (United States)

EPA registers disinfectants against Avian Influenza A. Although there are no antimicrobial products registered for the H5N2 subtype of Avian Influenza A virus, based on available scientific information these products will work against other HPAI strains.

[The principle of registration, evaluation and testing of disinfecting preparations].

Science.gov (United States)

Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta

2008-01-01

Disinfectants are used to produce a state in which the number of living micro-organisms has been reduced to a level which is appropriate to the practical situation. For any products which are included in the Biocidal Directive 98/8/EC, for which specific activity is claimed, test data has to be approved by the regulatory authority and a product license obtained before the product can be offered for sale. Disinfectants can be recorded as biocidal products or medical devices. Presently, it is possible to measure the activity of a product on defined micro-organisms in specified experimental conditions. Efficacy is the result of the use of a product according to a defined application. To allow different requirements in different areas of application, separate tests and pass criteria have been or will be prepared for each of following three areas of application: medical, veterinary and group comprising food, industrial, domestic and institutional areas. The laboratory methods to be used for testing the activity of chemical disinfectants meets the European standards. The tests are categorised on a modular basis as follows: phase 1 tests, phase 2 step 1 tests, phase 2 step 2 tests and phase 3 tests. In order to claim that a product has disinfectant properties, suitable for use in the medical area, the product shall be tested according to European standards: phase 2 step 1 tests, phase 2 step 2 tests. Phase 1 tests are not required to support claims for chemical disinfectants used in human medicine. Only phase 1 tests are required to support claims for active substances for which no particular area of application is specified. Medical devices are subjects to the European Directive 93/42/EEC which requires that a product must carry a CE mark. Disinfectants which are intended specifically by its manufacturer to be used on medical devices are themselves medical devices and so these products, as well as conforming to the instrument disinfection European standards as specified

Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

Science.gov (United States)

Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

2013-01-01

The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.

Drinking-Water Disinfection By-products and Semen Quality: A Cross-Sectional Study in China

Science.gov (United States)

Zeng, Qiang; Wang, Yi-Xin; Xie, Shao-Hua; Xu, Liang; Chen, Yong-Zhe; Li, Min; Yue, Jing; Li, Yu-Feng; Liu, Ai-Lin

2014-01-01

Background: Exposure to disinfection by-products (DBPs) has been demonstrated to impair male reproductive health in animals, but human evidence is limited and inconsistent. Objective: We examined the association between exposure to drinking-water DBPs and semen quality in a Chinese population. Methods: We recruited 2,009 men seeking semen analysis from the Reproductive Center of Tongji Hospital in Wuhan, China, between April 2011 and May 2012. Each man provided a semen sample and a urine sample. Semen samples were analyzed for sperm concentration, sperm motility, and sperm count. As a biomarker of exposure to drinking-water DBPs, trichloroacetic acid (TCAA) was measured in the urine samples. Results: The mean (median) urinary TCAA concentration was 9.58 (7.97) μg/L (interquartile range, 6.01–10.96 μg/L). Compared with men with urine TCAA in the lowest quartile, increased adjusted odds ratios (ORs) were estimated for below-reference sperm concentration in men with TCAA in the second and fourth quartiles (OR = 1.79; 95% CI: 1.19, 2.69 and OR = 1.51; 95% CI: 0.98, 2.31, respectively), for below-reference sperm motility in men with TCAA in the second and third quartiles (OR = 1.46; 95% CI: 1.12, 1.90 and OR = 1.30; 95% CI: 1.00, 1.70, respectively), and for below-reference sperm count in men with TCAA in the second quartile (OR 1.62; 95% CI: 1.04, 2.55). Nonmonotonic associations with TCAA quartiles were also estimated for semen parameters modeled as continuous outcomes, although significant negative associations were estimated for all quartiles above the reference level for sperm motility. Conclusion: Our findings suggest that exposure to drinking-water DBPs may contribute to decreased semen quality in humans. Citation: Zeng Q, Wang YX, Xie SH, Xu L, Chen YZ, Li M, Yue J, Li YF, Liu AL, Lu WQ. 2014. Drinking-water disinfection by-products and semen quality: a cross-sectional study in China. Environ Health Perspect 122:741–746; http://dx.doi.org/10.1289/ehp

Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO2) and their by-products hydrogen peroxide (H2O2) and chlorite (ClO2-).

Science.gov (United States)

Chhetri, Ravi Kumar; Baun, Anders; Andersen, Henrik Rasmus

2017-05-01

Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should be included in the evaluation of both their toxicity as determined in standardized tests and their possible negative effect in the water environment. Here we evaluated according to the standardized ISO 8692 test the toxicity towards the green microalgae, Pseudokirchneriella subcapitata, of three disinfectants: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO 2 ) as well as two by-products of their use: hydrogen peroxide (H 2 O 2 ) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC 50 values ranged from 0.16 to 2.9mg/L based on nominal concentrations leading to the labeling of the chemicals as either toxic or very toxic. The five investigated chemicals decreased in toxicity in the order chlorine dioxide, performic acid, peracetic acid, chlorite and hydrogen peroxide. The stability of the chemicals increased in the same order as the toxicity decrease. This indicates that even though ClO 2 has the highest environmental hazard potential, it may still be suitable as an alternative disinfectant due to its rapid degradation in water. Copyright © 2016 Elsevier GmbH. All rights reserved.

Exopolymeric substances from drinking water biofilms: Dynamics of production and relation with disinfection by products.

Science.gov (United States)

Lemus Pérez, M F; Rodríguez Susa, M

2017-06-01

Exopolymeric substances (EPS) as an external matrix of biofilm could react with disinfectants in drinking water networks forming disinfection by-products (DBP). Based on an experimental setup using two chlorine conditions-biofilm 1 (2.6 ± 0.8 mgCl/L) and biofilm 2 (0.7 ± 0.2 mg Cl/L)-samples of biofilms were recovered during 9 campaigns and EPS were extracted. Analyses of SUVA, fluorescence and amino acid (AA) content were carried out on the EPS to observe variation over time and correlations with DBP formation potential (DBP fp ) after chlorination. SUVA values were under 2 L/mgC*m showing that both EPS were hydrophilic. Slightly higher SUVA in biofilm 2 with low variation over time was observed. Fluorescence showed that aromatic proteins and fulvic like substances were the principal components and increased in biofilm 1 over time. AA decreased with time, and higher values of alanine, threonine, proline and isoleucine were observed in biofilm 2. Based on general associations, the SUVA of biofilm 2 correlated well with chloroform (CF) (r = 0.80). Generally, in both biofilms, tryptophan-like substances were negatively correlated with DBP while humic acid-like substances correlated positively, but with low indexes (r = 0.3-0.6). Correlations of data from individual sampling increased the indices (r over 0.8), suggesting a temporal influence of other factors on DBP fp such as inorganics, filtered water and the structural composition of EPS. In biofilm 1, Br-haloacetic acids (Br-HAA), dibromoacetonitrile and bromochloro acetonitrile were inversely associated with arginine and valine, as were di and trichloropropanone to arginine. On the contrary, in biofilm 2, the following amino acids correlated positively with DBP: alanine with Br-HAA, alanine with CF, alanine with N-DBP (chloropicrin, di and tri-chloro acetonitrile), and valine with CF. As this is the first report about the relation between temporal variation of EPS and DBP fp of biofilms in two

The determination and fate of disinfection by-products from ozonation of polluted raw water

International Nuclear Information System (INIS)

Huang, W.-J.; Fang, G.-C.; Wang, C.-C.

2005-01-01

The major disinfection by-products (DBPs) resulting from ozone treatment of polluted surface water were investigated. By-products of either health concern or which may contribute to biological instability of treated drinking water were investigated. The major DBPs were analyzed in two fractions: carbonyl compounds and brominated organic compounds. The natural organic matter (NOM) was also isolated and fractionated from polluted water for subsequent ozonation and DBPs identification under conditions of typical drinking treatment. The main identified carbonyl compounds were low molecular weight carboxylic acids, benzoic compounds, aliphatic aldehydes and odorous aldehydes, respectively. Brominated organics were also found in ozonated water, including bromoform (CHBr 3 ), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), 2,4-dibromophenol (2,4-DBP) and dibromoacetonitrile (DBAN), respectively. It was also found that the characteristic of organic precursors have significant influences on brominated organic by-products formation. Humic acid demonstrated the highest CHBr 3 , DBAA and 2,4-DBP formations, whereas hydrophilic neutral produced less CHBr 3 and 2,4-DBP than the rest of the organic fractions but produced the highest amount of DBAN. In addition to the other target compounds, a total of 59 different organic compounds were detected by means of gas chromatograph/high-resolution electron-impact mass spectrometry (GC/EI-MS) detection and tentatively identified using mass spectral library searching, mainly aromatics, acids/esters, alcohols, aldehydes, phthalates and amines/amino acids were analyzed. The percentage of elimination or formation levels reached during ozonation is also discussed in this study

Clinical and cost effectiveness of eight disinfection methods for terminal disinfection of hospital isolation rooms contaminated with Clostridium difficile 027.

Science.gov (United States)

Doan, L; Forrest, H; Fakis, A; Craig, J; Claxton, L; Khare, M

2012-10-01

Clostridium difficile spores can survive in the environment for months or years, and contaminated environmental surfaces are important sources of nosocomial C. difficile transmission. To compare the clinical and cost effectiveness of eight C. difficile environmental disinfection methods for the terminal cleaning of hospital rooms contaminated with C. difficile spores. This was a novel randomized prospective study undertaken in three phases. Each empty hospital room was disinfected, then contaminated with C. difficile spores and disinfected with one of eight disinfection products: hydrogen peroxide vapour (HPV; Bioquell Q10) 350-700 parts per million (ppm); dry ozone at 25 ppm (Meditrox); 1000 ppm chlorine-releasing agent (Actichlor Plus); microfibre cloths (Vermop) used in combination with and without a chlorine-releasing agent; high temperature over heated dry atomized steam cleaning (Polti steam) in combination with a sanitizing solution (HPMed); steam cleaning (Osprey steam); and peracetic acid wipes (Clinell). Swabs were inoculated on to C. difficile-selective agar and colony counts were performed pre and post disinfection for each method. A cost-effectiveness analysis was also undertaken comparing all methods to the current method of 1000 ppm chlorine-releasing agent (Actichlor Plus). Products were ranked according to the log(10) reduction in colony count from contamination phase to disinfection. The three statistically significant most effective products were hydrogen peroxide (2.303); 1000 ppm chlorine-releasing agent (2.223) and peracetic acid wipes (2.134). The cheaper traditional method of using a chlorine-releasing agent for disinfection was as effective as modern methods. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid.

Science.gov (United States)

Meinelt, Thomas; Phan, Thy-My; Behrens, Sascha; Wienke, Andreas; Pedersen, Lars-Flemming; Liu, Dibo; Straus, David L

2015-04-08

Peracetic acid (PAA) is a therapeutic agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harming the fish. Successful disinfectants (like PAA) should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. The aim of our study was to compare the effectiveness of 6 commercial PAA products with different molecular PAA:H2O2 ratios to reduce bacterial growth of Aeromonas salmonicida and Yersinia ruckeri and to determine effective concentrations and exposure times. All products reduced colony-forming units (CFUs) of A. salmonicida and Y. ruckeri. Products with higher molecular PAA:H2O2 ratios inhibited growth better than products with lower molecular PAA:H2O2 ratios at the same PAA concentration; this indicates that H2O2 is not the driving force in the reduction of A. salmonicida and Y. ruckeri growth by PAA in vitro. The practical application of the products with high molecular PAA:H2O2 ratios should be prioritized if these pathogens are diagnosed.

Disinfection of corrugated tubing by ozone and ultrasound in mechanically ventilated tracheostomized patients.

Science.gov (United States)

Lopes, M S; Ferreira, J R F; da Silva, K B; de Oliveira Bacelar Simplício, I; de Lima, C J; Fernandes, A B

2015-08-01

Medical equipment coming into contact with non-intact skin or mucous membranes is classified as semi-critical material. This equipment requires at least high-level disinfection, as the major risk in all invasive procedures is the introduction of pathogenic microbes causing hospital-associated infections. To evaluate the capacity of ozone gas and ultrasound to disinfect semi-critical, thermally sensitive material. Used corrugated tubing from mechanically ventilated tracheostomized patients in the intensive care unit was obtained. Enzymatic detergent was applied for 15min before different disinfection techniques were evaluated as follows: Group A (0.2% peracetic acid); Group B (ultrasound for 60min); Group C (application of ozone gas at a concentration of 33mg/L for 15min); Group D (ultrasound for 30min and ozone for 15min); Group E (ultrasound for 60min and ozone for 15min). Application of ultrasound for 60min reduced the level of microbial contamination by 4 log10, whereas ozone alone and the other two combined techniques (ultrasound and ozone) and the peracetic acid reduced the level of microbial contamination by 5 log10. Ozone was the most advantageous technique taking into consideration processing time, ease of use, effectiveness, and cost. The use of ozone gas to disinfect semi-critical material proved to be technically feasible and extremely promising. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs)

International Nuclear Information System (INIS)

Ashbolt, Nicholas John

2004-01-01

Managing the provision of safe drinking water has a renewed focus in light of the new World Health Organization (WHO) water safety plans. Risk analysis is a necessary component to assist in selecting priority hazards and identifying hazardous scenarios, be they qualitative to quantitative assessments. For any approach, acute diarrhoeal pathogens are often the higher risk issue for municipal water supplies, no matter how health burden is assessed. Furthermore, potential sequellae (myocarditis, diabetes, reactive arthritis and cancers) only further increase the potential health burden of pathogens; despite the enormous uncertainties in determining pathogen exposures and chemical dose-responses within respective microbial and chemical analyses. These interpretations are currently being improved by Bayesian and bootstrapping approaches to estimate parameters for stochastic assessments. A case example, covering the health benefits of ozonation for Cryptosporidium inactivation versus potential cancers from bromate exposures, illustrated the higher risks from a pathogen than one of the most likely disinfection by-products (DBPs). Such analyses help justify the industries long-held view of the benefits of multiple barriers to hazards and that microbial contamination of water supplies pose a clear public health risk when treatment is inadequate. Therefore, efforts to reduce potential health risks from DBP must not compromise pathogen control, despite socio-political issues

Bacterial spores survive treatment with commercial sterilants and disinfectants.

Science.gov (United States)

Sagripanti, J L; Bonifacino, A

1999-09-01

This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data obtained with a sensitive and quantitative test suggest that commercial liquid sterilants and disinfectants are less effective on contaminated surfaces than generally acknowledged.

A study of the formation of minority chlorination disinfection by-products; Estudio de la formacion de subproductos minoritarios de la desinfeccion con cloro

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Vidal, F. J.; Ibeas Reoyo, M. v.; Perez Serrano, A.; Orozco Barrenetxea, C.; Gonzalez Delgado, N. [Universidad de Burgos (Spain)

2001-07-01

Chlorine has been the traditional choice of chemical for the disinfection in drinking water treatment; however, chlorination of water can lead to the formation of disinfection by-products (DBPs). Tri halomethanes are the most abundant and studied volatile DBPs, but in recent years the study of the minority DBPs is becoming more and more important due to the possible health effects of these compounds and therefore, the need to establish maximum contaminant levels for their presence in public water supplies. In the present work, some of these minority DBPs are evaluated, di chloroacetonitrile (DCAN), chloropicrin or trichloronitromethane (CP) and 1.1,1-tetrachloroethane (TCAC), studying the main parameters influencing their formation: type and concentration of the precursor organic matter, presence of bromide ion, pH and influence of the previous ozonization treatment. (Author) 33 refs.

9 CFR 52.7 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... cleaning and disinfection, unless an official pseudorabies epidemiologist determines that a shorter or... and disinfection, except for cleaning and disinfection of the conveyances used to transport the swine... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances...

UV disinfection of water

International Nuclear Information System (INIS)

Skipperud, E.; Johansen; Myhrstad, J.A.

1978-01-01

UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

Limitation of the spread and impact of infectious coryza through the use of a continuous disinfection programme

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R.R. Bragg

2004-11-01

Full Text Available The effect of a continuous disinfection programme, using the non-toxic disinfectant Virukill, in layers, on the spread and impact of infectious coryza, caused by Haemophilus paragallinarum was evaluated. In this experiment, both unvaccinated layers and layers vaccinated against infectious coryza were used. Duplicate smaller groups of vaccinated and unvaccinated chickens were challenged with different serovars of both NAD-dependent as well as NAD-independent isolates of Haemophilus paragallinarum. One group of chickens challenged with each of the different bacterial serovars was treated with the continuous disinfection programme, while the other group remained as the untreated controls. The clinical signs of infectious coryza were evaluated over a period of 20 days in each group. The egg production over this period was also evaluated. It was found in all experimental challenges, that the severity of the symptoms was reduced in the birds receiving the continuous disinfection programme. The drop in egg production was also found to be less severe in the treated groups when compared to the untreated control groups. The duration of infection was found to be either unchanged, or shorter in the birds treated with the continuous disinfection programme. In none of the experimental challenges was the duration or expression of clinical signs of IC increased due to the continuous disinfection programme.

Bacterial Spores Survive Treatment with Commercial Sterilants and Disinfectants

OpenAIRE

Sagripanti, Jose-Luis; Bonifacino, Aylin

1999-01-01

This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data ob...

Evaluation of thirteen haloacetic acids and ten trihalomethanes formation by peracetic acid and chlorine drinking water disinfection.

Science.gov (United States)

Xue, Runmiao; Shi, Honglan; Ma, Yinfa; Yang, John; Hua, Bin; Inniss, Enos C; Adams, Craig D; Eichholz, Todd

2017-12-01

Free chlorine is a commonly used disinfectant in drinking water treatment. However, disinfection by-products (DBPs) are formed during water disinfection. Haloacetic acids (HAAs) and trihalomethanes (THMs) are two major groups of DBPs. Iodo-HAAs and iodo-THMs (I-HAAs and I-THMs) are formed during the disinfection of the water containing high levels of iodide and are much more toxic than their chlorinated and brominated analogs. Peracetic acid (PAA) is a strong antimicrobial disinfectant that is expected to reduce the formation of HAAs and THMs during disinfection. In this study, the formations of thirteen HAAs and ten THMs, including the iodinated forms, have been investigated during PAA disinfection and chlorination as the comparison. The DBP formations under different iodide concentrations, pHs, and contact times were systematically investigated. Two types of commercial PAAs containing different concentrations of PAA and hydrogen peroxide (H 2 O 2 ) were studied. A solid-phase microextraction gas chromatography-mass spectrometry method was upgraded for THM analysis including I-THMs. HAAs were analyzed by following a recently developed high performance ion chromatography-tandem mass spectrometry method. Results show that the ratio of PAA and H 2 O 2 concentration significantly affect the formation of I-THMs and I-HAAs. During PAA disinfection with lower PAA than H 2 O 2 , no detectable levels of THMs and HAAs were observed. During PAA disinfection with higher PAA than H 2 O 2 , low levels of monoiodoacetic acid, diiodoacetic acid, and iodoform were formed, and these levels were enhanced with the increase of iodide concentration. No significant quantities of chloro- or bromo-THMs and HAAs were formed during PAA disinfection treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

Science.gov (United States)

Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

2015-01-01

The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

Evaluation of disinfection efficiency in pet's hospital by using chlorine dioxide

Directory of Open Access Journals (Sweden)

Ching-Shan Hsu

2016-07-01

Full Text Available Microbial aerosols could cause various human and animal health problems and their control is becoming a significant scientific and technological topic for consideration. The main objectives of this study were to monitor bioaerosol levels of the pet's hospital and then to perform disinfection efficiency by applying chlorine dioxide. The air quality within these pet's hospitals should satisfy the guidelines specified by the Taiwan Environmental Protection Administration (TEPA. Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (0.3 mg m−3 treatments in disinfecting a local pet's hospital, namely a single, one-off application and a multiple-daily application. In both cases, the ClO2 was applied using strategically-placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. The experimental results found that the average background levels of bacteria and fungi prior to ClO2 disinfection were found to be 2014 ± 1350 and 1002 ± 669 CFU m−3, respectively. A single ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 57.3 and 57.6%. By contrast, a multiple-daily ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 65.1 and 57.6%. Among the two disinfection methods, the multiple-daily ClO2 application method was found to yield a higher disinfection efficiency for bacteria, i.e., 16.28 ± 0.92%. Thus, using a ClO2 disinfectant to maintain the air quality is of great importance to reduce infectious diseases in the pet's hospital. Therefore, the results suggest that the air quality guidelines prescribed by the TEPA for pet's hospital and other animal facilities can best be achieved by applying chlorine dioxide at regular intervals. The ClO2 aerosol devices can effectively restrain or

Ultraviolet light - nature's own disinfection process

Energy Technology Data Exchange (ETDEWEB)

Munkeberg, T [Thorolf Gregersen a/s, Oslo (Norway)

1978-05-18

Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m/sup 3/ /hr, though there is no reason why this should not be increased.

Ultraviolet light - nature's own disinfection process

International Nuclear Information System (INIS)

Munkeberg, T.

1978-01-01

Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m 3 /hr, though there is no reason why this should not be increased. (JIW)

Hospital disinfection: efficacy and safety issues.

Science.gov (United States)

Dettenkofer, Markus; Block, Colin

2005-08-01

To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments. The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products. Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.

Automated cleaning of fan coil units with a natural detergent-disinfectant product

Directory of Open Access Journals (Sweden)

Di Onofrio Valeria

2010-10-01

Full Text Available Abstract Background Air conditioning systems represent one important source of microbial pollutants for indoor air. In the past few years, numerous strategies have been conceived to reduce the contamination of air conditioners, mainly in hospital settings. The biocidal detergent BATT2 represents a natural product obtained through extraction from brown seaweeds, that has been tested previously on multidrug-resistant microorganisms. Methods BATT2 has been utilized for the disinfection of fan coil units from four air conditioning systems located in hospital environments with a mean degree of risk. Samples were collected from the air supplied by the conditioning systems and from the surfaces of fan coil units, before and after sanitization procedures. Total microbial counts at 37°C and 22°C and mycotic count at 32°C were evaluated. Staphylococci and Pseudomonas aeruginosa were also detected on surfaces samples. Results The biodetergent was able to reduce up 50% of the microbial pollution of fan coil units surfaces and air supplied by the air conditioners. Conclusions BATT2 could be considered for cleaning/disinfection of air conditioning systems, that should be performed on the basis of accurate and verifiable sanitization protocols.

Role of disinfection in the Infection Prevention Multibarrier System

OpenAIRE

Kramer, Axel

2007-01-01

The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safet...

Candida auris: Disinfectants and Implications for Infection Control.

Science.gov (United States)

Ku, Tsun S N; Walraven, Carla J; Lee, Samuel A

2018-01-01

Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris . Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

Chemical disinfection of combined sewer overflows

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar

of the residual disinfectants PFA, PAA and chlorine dioxide (ClO2), and their degradation products hydrogen peroxide and chlorite, in relation to organisms in the aquatic ecosystem was studied. With the help of ecotoxicity data, a preliminary environmental risk assessment of PFA, PAA and ClO2 for CSO disinfection...

Evaluation of Filtration and UV Disinfection for Inactivation of Viruses in Non-Community Water Systems in Minnesota

Science.gov (United States)

This study evaluated filtration and disinfection processes for removal and inactivation of pathogens in non-community water systems (NCWS) in two surface water supplies. Pretreatment systems included 1) pressure sand filtration, and 2) granular activated carbon adsorption, and 3...

9 CFR 77.41 - Cleaning and disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Captive Cervids § 77.41 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

Characterization of engineered nanoparticles in commercially available spray disinfectant products advertised to contain colloidal silver

Science.gov (United States)

Given the potential for human exposure to silver nanoparticles from spray disinfectants and dietary supplements, we characterized the silver-containing nanoparticles in 22 commercial products that advertised the use of silver or colloidal silver as the active ingredient. Characte...

9 CFR 77.19 - Cleaning and disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Cattle and Bison § 77.19 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

Fresh water disinfection by pulsed low electric field

International Nuclear Information System (INIS)

Zheng, C; Xu, Y; Liu, Z; Yan, K

2013-01-01

In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm −1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm −1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm −1 . When water conductivity is 25 μs cm −1 and bacteria density is 10 4 –10 6 cfu ml −1 , significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml −1 , while water temperature is below 30 °C.

PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

Directory of Open Access Journals (Sweden)

W. Luepcke

2017-12-01

Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

Assessment of peracetic acid disinfected effluents by microbiotests.

Science.gov (United States)

Antonelli, M; Mezzanotte, V; Panouillères, M

2009-09-01

Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and on secondary effluents (from two different wastewater treatment plants) after disinfection at bench-scale, considering both samples containing residual active PAA and the same samples where residual PAA was quenched. Four indicator organisms were used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Selenastrum capricornutum. The experiments lead to conclude that Thamnocephalus platyurus is a very sensitive organism, probably not adequate to perform a reliable toxicity assessment of effluents for monitoring purposes. The presence of specific organic compounds deriving from human metabolism and urban pollution, even at very low concentrations, can affect the results of bioassays, especially those performed on Vibrio fischeri. PAA is toxic for bacteria and crustaceans even at concentrations lower than the ones commonly used in wastewater disinfection (2-5 mg/L), while its effect on algae is smaller. The toxic effect on bacteria was expected, as PAA is used for disinfection, but its possible influence on biological processes in the receiving aquatic environment should be considered. Toxicity on crustaceans would confirm the fact that discharging disinfected effluents could raise some environmental problems.

Formation of Toxic Iodinated Disinfection By-Products from Compounds Used in Medical Imaging

Science.gov (United States)

Iodinated X-ray contrast media (ICM) were investigated as a source of iodine in the formation of iodo-trihalomethane (iodo-THM) and iodo-acid disinfection byproducts (DBPs), both of which are highly genotoxic and/or cytotoxic in mammalian cells. ICM are widely used at medical cen...

Impact of chlorinated disinfection on copper corrosion in hot water systems

Energy Technology Data Exchange (ETDEWEB)

Montes, J. Castillo [Centre Scientifique et Technique du Bâtiment Nantes, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 03 (France); Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Hamdani, F. [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Creus, J., E-mail: jcreus@univ-lr.fr [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Touzain, S. [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Correc, O. [Centre Scientifique et Technique du Bâtiment Nantes, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 03 (France)

2014-09-30

Highlights: • Impact of disinfectant treatment on the durability of copper pipes. • Synergy between disinfectant concentration and temperature. • Pitting corrosion of copper associated to the corrosion products formation on copper. - Abstract: In France, hot water quality control inside buildings is occasionally ensured by disinfection treatments using temperature increases or addition of sodium hypochlorite (between 0.5 ppm and 1 ppm residual free chlorine). This disinfectant is a strong oxidiser and it could interact with metallic pipes usually used in hot water systems. This work deals with the study of the impact of these treatments on the durability of copper pipes. The objective of this work was to investigate the influence of sodium hypochlorite concentration and temperature on the copper corrosion mechanism. Copper samples were tested under dynamic and static conditions of ageing with sodium hypochlorite solutions ranging from 0 to 100 ppm with temperature at 50 °C and 70 °C. The efficiency of a corrosion inhibitor was investigated in dynamic conditions. Visual observations and analytical analyses of the internal surface of samples was studied at different ageing duration. Corrosion products were characterised by X-ray diffraction and Raman spectroscopy. Temperature and disinfectant were found to considerably affect the copper corrosion mechanism. Surprisingly, the corrosiveness of the solution was higher at lower temperatures. The temperature influences the nature of corrosion products. The protection efficiency is then strongly depend on the nature of the corrosion products formed at the surface of copper samples exposed to the aggressive solutions containing different concentration of disinfectant.

Candida auris: Disinfectants and Implications for Infection Control

Directory of Open Access Journals (Sweden)

Tsun S. N. Ku

2018-04-01

Full Text Available Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

[Surface Cleaning and Disinfection in the Hospital. Improvement by Objective Monitoring and Intervention].

Science.gov (United States)

Woltering, R; Hoffmann, G; Isermann, J; Heudorf, U

2016-11-01

Background and Objective: An assessment of cleaning and disinfection in hospitals by the use of objective surveillance and review of mandatory corrective measures was undertaken. Methods: A prospective examination of the cleaning and disinfection of surfaces scheduled for daily cleaning in 5 general care hospitals by use of an ultraviolet fluorescence targeting method (UVM) was performed, followed by structured educational and procedural interventions. The survey was conducted in hospital wards, operating theatres and intensive care units. Cleaning performance was measured by complete removal of UVM. Training courses and reinforced self-monitoring were implemented after the first evaluation. 6 months later, we repeated the assessment for confirmation of success. Results: The average cleaning performance was 34% (31/90) at base-line with significant differences between the 5 hospitals (11-67%). The best results were achieved in intensive care units (61%) and operating theatres (58%), the worst results in hospital wards (22%). The intervention significantly improved cleaning performance up to an average of 69% (65/94; +34.7%; 95% confidence interval (CI): 21.2-48.3; pcleaning and disinfection of surfaces by fluorescence targeting is appropriate for evaluating hygiene regulations. An intervention can lead to a significant improvement of cleaning performance. As part of a strategy to improve infection control in hospitals, fluorescence targeting enables a simple inexpensive and effective surveillance of the cleaning performance and corrective measures. © Georg Thieme Verlag KG Stuttgart · New York.

Non-canonical regulation of glutathione and trehalose biosynthesis characterizes non-Saccharomyces wine yeasts with poor performance in active dry yeast production

Directory of Open Access Journals (Sweden)

Esther Gamero-Sandemetrio

2018-01-01

Full Text Available Several yeast species, belonging to Saccharomyces and non-Saccharomyces genera, play fundamental roles during spontaneous must grape fermentation, and recent studies have shown that mixed fermentations, co-inoculated with S. cerevisiae and non-Saccharomyces strains, can improve wine organoleptic properties. During active dry yeast (ADY production, antioxidant systems play an essential role in yeast survival and vitality as both biomass propagation and dehydration cause cellular oxidative stress and negatively affect technological performance. Mechanisms for adaptation and resistance to desiccation have been described for S. cerevisiae, but no data are available on the physiology and oxidative stress response of non-Saccharomyces wine yeasts and their potential impact on ADY production. In this study we analyzed the oxidative stress response in several non-Saccharomyces yeast species by measuring the activity of reactive oxygen species (ROS scavenging enzymes, e.g., catalase and glutathione reductase, accumulation of protective metabolites, e.g., trehalose and reduced glutathione (GSH, and lipid and protein oxidation levels. Our data suggest that non-canonical regulation of glutathione and trehalose biosynthesis could cause poor fermentative performance after ADY production, as it corroborates the corrective effect of antioxidant treatments, during biomass propagation, with both pure chemicals and food-grade argan oil.

Regulation of non-relevant metabolites of plant protection products in drinking and groundwater in the EU: Current status and way forward.

Science.gov (United States)

Laabs, V; Leake, C; Botham, P; Melching-Kollmuß, S

2015-10-01

Non-relevant metabolites are defined in the EU regulation for plant protection product authorization and a detailed definition of non-relevant metabolites is given in an EU Commission DG Sanco (now DG SANTE - Health and Food Safety) guidance document. However, in water legislation at EU and member state level non-relevant metabolites of pesticides are either not specifically regulated or diverse threshold values are applied. Based on their inherent properties, non-relevant metabolites should be regulated based on substance-specific and toxicity-based limit values in drinking and groundwater like other anthropogenic chemicals. Yet, if a general limit value for non-relevant metabolites in drinking and groundwater is favored, an application of a Threshold of Toxicological Concern (TTC) concept for Cramer class III compounds leads to a threshold value of 4.5 μg L(-1). This general value is exemplarily shown to be protective for non-relevant metabolites, based on individual drinking water limit values derived for a set of 56 non-relevant metabolites. A consistent definition of non-relevant metabolites of plant protection products, as well as their uniform regulation in drinking and groundwater in the EU, is important to achieve legal clarity for all stakeholders and to establish planning security for development of plant protection products for the European market. Copyright © 2015 Elsevier Inc. All rights reserved.

An EPR study on wastewater disinfection by peracetic acid, hydrogen peroxide and UV irradiation.

Science.gov (United States)

Bianchini, Roberto; Calucci, Lucia; Caretti, Cecilia; Lubello, Claudio; Pinzino, Calogero; Piscicelli, Michela

2002-09-01

EPR spectroscopy was applied to obtain qualitative and quantitative information on the radicals produced in disinfection processes of wastewater for agricultural reuse. The DEPMPO spin trap was employed to detect hydroxyl and carbon-centered short living radicals in two different peracetic acid solutions and a hydrogen peroxide solution used for water disinfection either in the absence or in the presence of UV-C irradiation. Moreover, three different kinds of water (wastewater, demineralized water, distilled water) were analysed in order to assess the contribution of Fenton reactions to the radical production. The spectroscopic results were discussed in relation to the efficiency of the different oxidizing agents and UV irradiation in wastewater disinfection evaluated as Escherichia Coli, Faecal and Total Coliforms inactivation.

Sludge disinfection using gamma radiation: a sound option for Albuquerque

International Nuclear Information System (INIS)

Noland, P.D.; Khera, A.K.

1980-01-01

The City of Albuquerque has disposed of its anaerobically digested dried sludge cake on City and county parks for many years. If the City is to continue such beneficial use of sludge, it must now provide a supplementary disinfection process in order to meet the recent EPA regulations governing land application of sewage sludges. In light of these recent regulations and soaring costs of electrical energy, the City of Albuquerque recently completed a comprehensive sludge management study. This study is intended to supplement the areawide facilities plan completed in 1976. Among the various alternatives evaluated, the most feasible was the continued use of dried sludge cake on City parks and sale of excess sludge cake as an unlimited use soil conditioner and fertilizer. This sludge would be disinfected by gamma irradiation. The proposed solids management system would consist of two-stage anaerobic digestion and pipeline transfer to dewatering, disinfection, and stockpiling facilities at a remote tract approximately 5 miles from the treatment plant

Secondary formation of disinfection by-products by UV treatment of swimming pool water

Energy Technology Data Exchange (ETDEWEB)

Spiliotopoulou, Aikaterini [Water ApS, Farum Gydevej 64, 3520 Farum (Denmark); Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Hansen, Kamilla M.S., E-mail: kmsh@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Andersen, Henrik R. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark)

2015-07-01

Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

Secondary formation of disinfection by-products by UV treatment of swimming pool water

International Nuclear Information System (INIS)

Spiliotopoulou, Aikaterini; Hansen, Kamilla M.S.; Andersen, Henrik R.

2015-01-01

Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

Technical considerations during disinfection by UV

International Nuclear Information System (INIS)

Ekhtiarzadeh, Z.; Sadeghpur, H.

2002-01-01

The use of new methods for treatment of water and wastewater in the country is one the rise and therefore the theoretical and practical knowledge of the industry's engineers should increase simultaneously. Ultraviolet is one of the new technologies used both for treatment of water as well as wastewater. The UV disinfection system consists of different components such as the lamp, ballast and the lamp fixtures. Each has a specification, which should be taken into account prior to design, order and purchase. The subject of price is also among the important considerations. The article presents figures cost comparison in various sections. It does not try to either approve or reject other disinfection systems such as chlorination, but the writer believes that any method should find its own practice and conditions of use, and the disinfection system designers should opt for the best system suited to their plans and avoid limiting themselves to a single one

Chloramination of Concentrated Drinking Water for Disinfection Byproduct Mixtures Creation- Indianapolis

Science.gov (United States)

Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

Mangotoxin production of Pseudomonas syringae pv. syringae is regulated by MgoA.

Science.gov (United States)

Carrión, Víctor J; van der Voort, Menno; Arrebola, Eva; Gutiérrez-Barranquero, José A; de Vicente, Antonio; Raaijmakers, Jos M; Cazorla, Francisco M

2014-02-21

The antimetabolite mangotoxin is a key factor in virulence of Pseudomonas syringae pv. syringae strains which cause apical necrosis of mango trees. Previous studies showed that mangotoxin biosynthesis is governed by the mbo operon. Random mutagenesis led to the identification of two other gene clusters that affect mangotoxin biosynthesis. These are the gacS/gacA genes and mgo operon which harbors the four genes mgoBCAD. The current study shows that disruption of the nonribosomal peptide synthetase (NRPS) gene mgoA resulted in loss of mangotoxin production and reduced virulence on tomato leaves. Transcriptional analyses by qPCR and promoter reporter fusions revealed that mbo expression is regulated by both gacS/gacA and mgo genes. Also, expression of the mgo operon was shown to be regulated by gacS/gacA. Heterologous expression under the native promoter of the mbo operon resulted in mangotoxin production in non-producing P. syringae strains, but not in other Pseudomonas species. Also introduction of the mbo and mgo operons in nonproducing P. protegens Pf-5 did not confer mangotoxin production but did enhance transcription of the mbo promoter. From the data obtained in this study, we conclude that both mbo and mgo operons are under the control of the gacS/gacA two-component system and that the MgoA product acts as a positive regulator of mangotoxin biosynthesis.

The tail of two models: Impact of circularity and biomass non-homogeneity on UV disinfection of wastewater flocs.

Science.gov (United States)

Azimi, Y; Liu, Y; Tan, T C; Allen, D G; Farnood, R R

2017-12-01

The effects of floc structural characteristics, i.e. shape and dense biomass distribution, were evaluated on ultraviolet (UV) disinfection resistance, represented by the tailing level of the UV dose response curve (DRC). Ellipsoid-shaped flocs of similar volume and different projected circularities were constructed in-silico and a mathematical model was developed to compare their UV DRC tailing levels (indicative of UV-resistance). It was found that floc shape can significantly influence tailing level, and rounder flocs (i.e. flocs with higher circularity) were more UV-resistant. This result was confirmed experimentally by obtaining UV DRCs of two 75-90 μm floc populations with different percentages (20% vs. 30%) of flocs with circularities higher than 0.5. The population enriched in less circular flocs (i.e. 20% flocs with circularities >0.5) had a lower tailing level (at least by 1-log) compared to the other population. The second model was developed to describe variations in UV disinfection kinetics observed in flocs with transverse vs. radial biomass non-homogeneity, indicative of biofilm-originated vs. suspended flocs. The varied-density hemispheres model and shell-core model were developed to simulate transverse and radial non-homogeneity, respectively. The UV DRCs were mathematically constructed and biofilm-originated flocs showed higher UV resistance compared to suspended flocs. The calculated UV DRCs agreed well with the experimental data collected from activated sludge and trickling filter flocs (no fitting parameters were used). These findings provide useful information in terms of designing/modifying upstream processes for reducing UV disinfection energy demand. Copyright © 2017 Elsevier Ltd. All rights reserved.

9 CFR 53.7 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... least 7 days following such cleaning and disinfection, unless the Administrator determines that a... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... LIVESTOCK OR POULTRY § 53.7 Disinfection of premises, conveyances, and materials. All premises, including...

Efficacy of disinfectants and detergents intended for a pig farm environment where Salmonella is present.

Science.gov (United States)

Gosling, Rebecca J; Mawhinney, Ian; Vaughan, Kelly; Davies, Robert H; Smith, Richard P

2017-05-01

Disinfection is a useful component of disease control, although products and chemical groups vary in their activity against different pathogens. This study investigated the ability of fifteen disinfectants to eliminate pig-associated Salmonella. Active compounds of products included chlorocresol, glutaraldehyde/formaldehyde, glutaraldehyde/quaternary ammonium compounds (QAC), iodine, peracetic acid and potassium peroxomonosulphate. Six detergents were also tested for their ability to dislodge faecal material, and interactions with specific disinfectants. Eight serovars were screened against all products using dilution tests and a monophasic Salmonella Typhimurium strain was selected for further testing. The disinfectants were tested using models to replicate boot dip (faecal suspension) and animal housing (surface contamination) disinfection respectively at the Department for Environment, Food and Rural Affairs Approved Disinfectant General Orders (GO) concentration, half GO and twice GO. Stability over time and ability to eliminate Salmonella in biofilm was also assessed. The most effective products were then field tested. Most products at GO concentration eliminated Salmonella in the faecal suspension model. One glutaraldehyde/QAC and one glutaraldehyde/formaldehyde-based product at GO concentration eliminated Salmonella in the surface contamination model. Chlorocresol-based products were more stable in the faecal suspension model. One chlorocresol and the glutaraldehyde/formaldehyde-based product were most successful in eliminating Salmonella from biofilms. All products tested on farm reduced bacterial log counts; the glutaraldehyde/QAC based product produced the greatest reduction. The type of product and the application concentration can impact on efficacy of farm disinfection; therefore, clearer guidance is needed to ensure the appropriate programmes are used for specific environments. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

9 CFR 51.8 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... facilities, conveyances, or other materials on the premises that would require such cleaning and disinfection... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Cattle, Bison, and Swine § 51.8 Disinfection of...

Application of a high-level peracetic acid disinfection protocol to re-process antibiotic disinfected skin allografts.

Science.gov (United States)

Lomas, R J; Huang, Q; Pegg, D E; Kearney, J N

2004-01-01

Skin allografts, derived from cadaveric donors, are widely used for the treatment of burns and ulcers. Prior to use in clinical situations, these allografts are disinfected using a cocktail of antibiotics and then cryopreserved. Unfortunately, this antibiotic disinfection procedure fails to decontaminate a significant proportion and these contaminated grafts can not be used clinically. We have investigated whether it is possible to apply a second, more potent disinfection procedure to these contaminated grafts and effectively to re-process them for clinical use. Cadaveric skin grafts, treated with antibiotics and cryopreserved, were thawed and a peracetic acid (PAA) disinfection protocol applied. The grafts were then preserved in a high concentration of glycerol or propylene glycol, and properties thought to be essential for successful clinical performance assessed. The cytotoxicity of the grafts was assessed using both extract and contact assays; damage to the skin collagen was assessed using a collagenase susceptibility assay and the capacity of the grafts to elicit an inflammatory response in vitro was assessed by quantifying the production of the pro-inflammatory cytokine TNF-alpha by human peripheral blood mononuclear phagocytes. PAA disinfection, in conjunction with either glycerol or propylene glycol preservation, did not render the grafts cytotoxic, pro-inflammatory, or increase their susceptibility to collagenase digestion. The rates of penetration of glycerol and propylene glycol into the re-processed skin were comparable to those of fresh skin. This study has demonstrated that PAA disinfection combined with immersion in high concentrations of either glycerol or propylene glycol was an effective method for re-processing contaminated skin allografts, and may justify their clinical use.

The efficiency of water treatment and disinfection by means of ultraviolet radiation

International Nuclear Information System (INIS)

Sobotka, J.

1993-01-01

Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, α absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The α absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author)

The efficiency of water treatment and disinfection by means of ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Sobotka, J [Medical Academy, Warsaw (Poland). Inst. of Social Medicine

1993-01-01

Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, [alpha] absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The [alpha] absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author).

Production of T-2 toxin and deoxynivalenol in the presence of different disinfectants

OpenAIRE

Dana Hrubošová; Jarmila Vytřasová; Iveta Brožková

2015-01-01

The aim of the work was to examine the effect of different disinfectants on production trichothecenes (especially of T-2 toxin and deoxynivalenol). Lipophilicity, chemical structure, the presence of bioactive groups and functional groups in their structure modifies biological activity and toxic potency of trichothecenes. For this reason, limits have been established designating maximum levels of mycotoxins in cereals while maintaining proper growing practices. Appropriate nutr...

Disinfection of wastewater with peracetic acid: a review.

Science.gov (United States)

Kitis, Mehmet

2004-03-01

Peracetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. The desirable attributes of peracetic acid for wastewater disinfection are the ease of implementing treatment (without the need for expensive capital investment), broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residuals or by-products, no quenching requirement (i.e., no dechlorination), small dependence on pH, short contact time, and effectiveness for primary and secondary effluents. Major disadvantages associated with peracetic acid disinfection are the increases of organic content in the effluent due to acetic acid (AA) and thus in the potential microbial regrowth (acetic acid is already present in the mixture and is also formed after peracetic acid decomposition). Another drawback to the use of peracetic acid is its high cost, which is partly due to limited production capacity worldwide. However, if the demand for peracetic acid increases, especially from the wastewater industry, the future mass production capacity might also be increased, thus lowering the cost. In such a case, in addition to having environmental advantages, peracetic acid may also become cost-competitive with chlorine.

Surface Disinfectants for Burn Units Evaluated by a New Double Method, Using Microorganisms Recently Isolated From Patients, on a Surface Germ-Carrier Model.

Science.gov (United States)

Herruzo, Rafael; Vizcaino, Maria Jose; Herruzo, Irene; Sanchez, Manuel

Assessment methods of surface disinfection based on international standards (Environmental Protection Agency, European Norms, etc) do not correspond to hospital reality. New evaluation methods of surfaces disinfection are proposed to choose the most suitable disinfectant to act against clinically relevant microorganisms detected on the surfaces of burn units. 1) "Immediate effect": 6 products were compared using a glass germ-carrier and 20 recently isolated microorganisms from different patients in the intensive care units. Disinfectants were applied with microfiber cloths. Log10 reductions were calculated for colony forming units produced after 15 minutes of disinfectant application. 2) "Residual effect": the glass germ-carriers were previously impregnated with one of the studied disinfectants. After a 30-minute wait period, they were then contaminated with 1 microorganism (from the 20 above-mentioned). After 15 minutes, the disinfectant was inhibited and the log10 reduction of colony forming units was assessed. The immediate effect (disinfection and microorganism dragging and transferring from the surface to the cloth) produced complete elimination of the inoculums for all products used except one (a diluted quaternary ammonium). The average residual effect found on the 20 microorganisms was moderate: 2 to 3 log10 colony forming unit reduction with chlorine dioxide or 0.5% chlorhexidine (and lower with the other products), obtaining surfaces refractory to recontamination, at least, during 30 minutes. Two tests should be performed before advising surface disinfectant: 1) direct effect and 2) residual efficacy. These characteristics should be considered when a new surface disinfectant is chosen. Chlorine dioxide has a similar or better direct effect than sodium hypochlorite and a similar residual effect than chlorhexidine.

A pilot solar water disinfecting system: performance analysis and testing

Energy Technology Data Exchange (ETDEWEB)

Saitoh, T.S.; El-Ghetany, H.H. [Tohoku University, Sendai (Japan). Dept. of Aeronautics and Space Engineering

2002-07-01

In most countries, contaminated water is the major cause of most water-borne diseases. Disinfection of water may be accomplished by a number of different physical-chemical treatments including direct application of thermal energy, chemical and filtration techniques. Solar energy also can be used effectively in this field because inactivation of microorganisms is done either by heating water to a disinfecting temperature or by exposing it to ultraviolet solar radiation. A pilot solar system for disinfecting contaminated water is designed, constructed and tested. Investigations are carried out to evaluate the performance of a wooden hot box solar facility as a solar disinfectant. Experimental data show that solar energy is viable for the disinfection process. A solar radiation model is presented and compared with the experimental data. A mathematical model of the solar disinfectant is also presented. The governing equations are solved numerically via the fourth-order Runge-Kutta method. The effects of environmental conditions (ambient temperature, wind speed, solar radiation, etc.) on the performance of the solar disinfectant are examined. Results showed that the system is affected by ambient temperature, wind speed, ultraviolet solar radiation intensity, the turbidity of the water, the quantity of water exposed, the contact area between the transparent water container in the solar disinfectant and the absorber plate as well as the geometrical parameters of the system. It is pointed out that for partially cloudy conditions with a low ambient temperature and high wind speeds, the thermal efficiency of the solar disinfectant is at a minimum. The use of solar energy for the disinfection process will increase the productivity of the system while completely eliminating the coliform group bacteria at the same time. (author)

Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

Science.gov (United States)

Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

2015-10-01

Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (P<0.0001). Multicomponent suction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces

Pyruvate remediation of cell stress and genotoxicity induced by haloacetic acid drinking water disinfection by-products.

Science.gov (United States)

Dad, Azra; Jeong, Clara H; Pals, Justin A; Wagner, Elizabeth D; Plewa, Michael J

2013-10-01

Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by-products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA-mediated inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration-dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) > chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA-induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the SN 2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. Copyright © 2013 Wiley Periodicals, Inc.

Disinfection efficiency of peracetic acid (PAA): inactivation of coliphages and bacterial indicators in a municipal wastewater plant.

Science.gov (United States)

Zanetti, F; De Luca, G; Sacchetti, R; Stampi, S

2007-11-01

The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.

[Legislative regulation of production and turnover of products for people with different diseases].

Science.gov (United States)

Pritul'skaia, N V; Motuzka, Iu N; Antiushko, D L

2013-01-01

This article presents results of analysis of existing regulatory documents and approaches to the legislative regulation of production and turnover of special dietary products for people with specific diseases in EU, Ukraine and Russian Federation. According to the EU legislation, production and turnover of food products for nutritional support of people during specific diseases and the rehabilitation period are regulated by the Commission Directive 1999/21/EC, 2009/39/ES, by Regulation Commission (EU) No 953/2009 and documents of Codex Committee. Special food products for people with specific diseases in Ukrainian legislation are classified as nutrition products for special dietary use and are regulated by the following Laws of Ukraine "On the safety and quality of food", "On ensuring of sanitary and epidemiological welfare of the population", "On Consumer Rights Protection", "On advertising" and by other non-legislative acts. According to the current legislation of the Russian Federation, the products for people with specific diseases are classified as healthy dietary food products. The basis of the legal framework are federal laws "On the quality and safety of food", "On the sanitary-epidemiological welfare of the populations", "On technical regulations and technical regulations of the Customs Union "On Food Safety" and "On the safety of certain types of specialized food products, including healthy dietary food products and therapeutic dietary food products". There is no common approach to the legal regulation of production and turnover of products for people with specific diseases in the world. The proposals for further harmonization of regulatory control in this area have been developed.

Formation of N-nitrosodimethylamine (NDMA) from reaction of monochloramine: a new disinfection by-product.

Science.gov (United States)

Choi, Junghoon; Valentine, Richard L

2002-02-01

Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed from the reaction between DMA and monochloramine indicating that it should be considered a potential disinfection by-product. The formation of NDMA increased with increased monochloramine concentration and showed maximum in yield when DMA was varied at fixed monochloramine concentrations. The mass spectra of the NDMA formed from DMA and 15N isotope labeled monochloramine (15NH2Cl) showed that the source of one of the nitrogen atoms in the nitroso group in NDMA was from monochloramine. Addition of 0.05 and 0.5 mM of preformed monochloramine to a secondarily treated wastewater at pH 7.2 also resulted in the formation of 3.6 and 111 ng/L of NDMA, respectively, showing that this is indeed an environmentally relevant NDMA formation pathway. The proposed NDMA formation mechanism consists of (i) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (ii) the oxidation of UDMH by monochloramine to NDMA, and (iii) the reversible chlorine transfer reaction between monochloramine and DMA which is parallel to (i). We conclude that reactions involving monochloramine in addition to classical nitrosation reactions are potentially important pathways for NDMA formation.

The effectiveness of three home products in cleaning and disinfection of Staphylococcus aureus and Escherichia coli on home environmental surfaces.

Science.gov (United States)

Goodyear, N; Brouillette, N; Tenaglia, K; Gore, R; Marshall, J

2015-11-01

The objectives of this study were to investigate three products for: (i) cleaning effectiveness on two common household surfaces, and (ii) disinfection effectiveness against two common bacteria. Products included conventional ('bleach'), environmentally preferable (EP), do-it-yourself (DIY: distilled white vinegar, club soda, tea tree oil), 24-h old DIY, and individual DIY components in dilution. For cleaning ceramic, no product was effective (≥85% removal of Hucker's soil), however, DIY performed better than EP and bleach. On stainless, only DIY failed to meet the standard. For disinfection, bleach and EP achieved ≥5·00 log10 reductions under all conditions. DIY and components were more active against Escherichia coli than Staphylococcus aureus but only fresh DIY and 50% vinegar achieved ≥5·00 log10 reductions. EP is an effective alternative to bleach. DIY may be an adequate alternative for cleaning ceramic and for household use, where complete elimination of micro-organisms is unnecessary; however, it must be freshly prepared each day. This is the first report of performance of purportedly safer alternatives for both cleaning and disinfection for use in home health care. The EP product and DIY are potential alternatives for some household uses. © 2015 The Society for Applied Microbiology.

Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA.

Directory of Open Access Journals (Sweden)

Ebrahim Aboualizadeh

Full Text Available Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300. FTIR spectroscopy permits a detailed characterization of bacterial reactivity, allowing an understanding of the fundamental mechanism of action involved in the interaction between bacteria and disinfectants. The disinfectants studied were ethanol 70% (N = 5, isopropanol (N = 5, sodium hypochlorite (N = 5, triclosan (N = 5 and triclocarban (N = 5. Results showed less than 5% colony forming units growth of MRSA treated with triclocarban and no growth in the other groups. Nearly 70,000 mid-infrared spectra from the five treatments and the two control (untreated; N = 4 groups of MRSA (bacteria grown in TSB and incubated at 37°C (Control I / at ambient temperature (Control II, for 24h were pre-processed and analyzed using principal component analysis followed by linear discriminant analysis (PCA-LDA. Clustering of strains of MRSA belonging to five treatments and the discrimination between each treatment and two control groups in MRSA (untreated were investigated. PCA-LDA discriminatory frequencies suggested that ethanol-treated spectra are the most similar to isopropanol-treated spectra biochemically. Also reported here are the biochemical alterations in the structure of proteins, lipid membranes, and phosphate groups of MRSA produced by sodium hypochlorite, triclosan, and triclocarban treatments. These findings provide mechanistic information involved in the

Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA).

Science.gov (United States)

Aboualizadeh, Ebrahim; Bumah, Violet V; Masson-Meyers, Daniela S; Eells, Janis T; Hirschmugl, Carol J; Enwemeka, Chukuka S

2017-01-01

Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR) spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300. FTIR spectroscopy permits a detailed characterization of bacterial reactivity, allowing an understanding of the fundamental mechanism of action involved in the interaction between bacteria and disinfectants. The disinfectants studied were ethanol 70% (N = 5), isopropanol (N = 5), sodium hypochlorite (N = 5), triclosan (N = 5) and triclocarban (N = 5). Results showed less than 5% colony forming units growth of MRSA treated with triclocarban and no growth in the other groups. Nearly 70,000 mid-infrared spectra from the five treatments and the two control (untreated; N = 4) groups of MRSA (bacteria grown in TSB and incubated at 37°C (Control I) / at ambient temperature (Control II), for 24h) were pre-processed and analyzed using principal component analysis followed by linear discriminant analysis (PCA-LDA). Clustering of strains of MRSA belonging to five treatments and the discrimination between each treatment and two control groups in MRSA (untreated) were investigated. PCA-LDA discriminatory frequencies suggested that ethanol-treated spectra are the most similar to isopropanol-treated spectra biochemically. Also reported here are the biochemical alterations in the structure of proteins, lipid membranes, and phosphate groups of MRSA produced by sodium hypochlorite, triclosan, and triclocarban treatments. These findings provide mechanistic information involved in the interaction

Acute toxicity of dichloroacetonitrile (DCAN), a typical nitrogenous disinfection by-product (N-DBP), on zebrafish (Danio rerio).

Science.gov (United States)

Lin, Tao; Zhou, Dongju; Dong, Jian; Jiang, Fuchun; Chen, Wei

2016-11-01

Dichloroacetonitrile (DCAN) is a typical nitrogenous disinfection by-product (N-DBP) and its toxicity on aquatic animals is investigated for the first time. The present study was designed to investigate the potential adverse effects of DCAN on zebrafish. DCAN could induce developmental toxicity to zebrafish embryos. A significant decrease in hatchability and an increase in malformation and mortality occurred when DCAN concentration was above 100µg/L. Heart function alteration and neuronal function disturbance occurred at concentration higher than 500 and 100µg/L, respectively. Further, DCAN was easily accumulated in adult zebrafish. The rank order of declining bioconcentration factor (BCF) was liver (1240-1670)> gill (1210-1430)> muscle (644-877). DCAN caused acute metabolism damage to adult zebrafish especially at 8 days exposure, at which time the "Integrated Biomarker Response" (IBR) index value reached 798 at 1mg/L DCAN dose. Acute DNA damage was induced to adult zebrafish by DCAN even at 10µg/L dose. Copyright © 2016 Elsevier Inc. All rights reserved.

Disinfection of Streptococcus mutans biofilm by a non-thermal atmospheric plasma brush

Science.gov (United States)

Hong, Qing; Dong, Xiaoqing; Chen, Meng; Xu, Yuanxi; Sun, Hongmin; Hong, Liang; Wang, Yong; Yu, Qingsong

2016-07-01

This study investigated the argon plasma treatment effect on disinfecting dental biofilm by using an atmospheric pressure plasma brush. Streptococcus mutans biofilms were developed for 3 days on the surfaces of hydroxyapatite (HA) discs, which were used to simulate human tooth enamel. After plasma treatment, cell viability in the S. mutans biofilms was characterized by using 3-(4,5-dimethylazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and confocal laser scanning microscopy (CLSM). Compared with the untreated control group, about 90% bacterial reduction in the biofilms was observed after 1 min plasma treatment. Scanning electron microscopy (SEM) examination indicated severe cell damages occurred on the top surface of the plasma treated biofilms. Confocal laser scanning microscopy (CLSM) showed that plasma treatment was effective as deep as 20 µm into the biofilms. When combined with antibiotic treatment using 0.2% chlorhexidine digluconate solution, the plasma treatment became more effective and over 96% bacterial reduction was observed with 1 min plasma treatment.

Influence of sublethal concentrations of common disinfectants on expression of virulence genes in Listeria monocytogenes

DEFF Research Database (Denmark)

Kastbjerg, Vicky Gaedt; Larsen, M. H.; Gram, Lone

2010-01-01

Listeria monocytogenes is a food-borne human pathogen that causes listeriosis, a relatively rare infection with a high fatality rate. The regulation of virulence gene expression is influenced by several environmental factors, and the aim of the present study was to determine how disinfectants use......, such as antibiotic resistance....... by Northern blot analysis. Eleven disinfectants representing four different groups of active components were evaluated in this study. Disinfectants with the same active ingredients had a similar effect on gene expression. Peroxy and chlorine compounds reduced the expression of the virulence genes...

Spiral-shaped disinfection reactors

KAUST Repository

Ghaffour, Noreddine

2015-08-20

This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

Science.gov (United States)

Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

2015-04-01

Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection. Published by Elsevier Inc.

Effect of disinfecting teats post-milking or pre- and post-milking on intramammary infection and somatic cell count.

Science.gov (United States)

Williamson, J H; Lacy-Hulbert, S J

2013-09-01

To determine the effects of (a) post-milking teat disinfection compared with no disinfection and (b) pre- and post-milking teat disinfection compared with post-milking disinfection alone, on the incidence of new intramammary infection (IMI), somatic cell count (SCC) and teat skin abnormalities in dairy cows. In Experiment 1, dairy cows in five dairy herds were randomly allocated to a post-milking teat disinfection group (n=230), that was sprayed with an iodine-based disinfectant (TeatguardPlus) for a complete lactation, or to a non-disinfected group (n=239). In Experiment 2, cows were randomly allocated to post-milking teat disinfection (n=239) or both pre- and post-milking teat disinfection (n=235), using a chloramine-T-based disinfectant (Teatsweet) for both treatments, from calving to 118-127 days in milk. The incidence of new IMI was determined by aseptic sampling of all quarters at calving, during lactation, and at trial end or at drying-off, with clinical mastitis cases sampled on detection. SCC and teat skin abnormalities were measured at 2-monthly intervals during lactation. In both experiments, disinfectant was applied by spray application. Cows that received post-milking teat disinfection had a lower incidence of new IMI caused by Staphylococcus aureus, Streptococcus uberis, Corynebacterium spp and coagulase negative staphylococci, had lower bulk milk SCC during lactation, and had fewer teat skin abnormalities compared with the non-disinfected cows (p disinfection, in addition to post-milking teat disinfection, did not reduce the incidence of new IMI for any pathogens and did not reduce SCC (p> 0.05). Post-milking teat disinfection applied as a spray is a key component in mastitis control in New Zealand. There was no benefit from the addition of pre-milking disinfection. This study confirms previous findings of the effectiveness of post-milking teat disinfection in reducing the incidence of IMI caused by the common mastitis-causing pathogens in New

Insusceptibility to disinfectants in bacteria from animals, food and humans – is there a link to antimicrobial resistance?

Directory of Open Access Journals (Sweden)

Karin eSchwaiger

2014-03-01

Full Text Available Enterococcus faecalis (n = 834 and Enterococcus faecium (n = 135 from blood and feces of hospitalized humans, from feces of outpatients and livestock and from food were screened for their susceptibility to a quaternary ammonium compound (didecyldimethyl-ammoniumchloride, DDAC and to 28 antibiotics by micro-/macrodilution. The maximum DDAC-MIC in our field study was 3.5 mg/l, but after adaptation in the laboratory, MIC values of 21.9 mg/l were observed. Strains for which DDAC had MICs > 1.4 mg/l (non-wildtype, in total: 46 of 969 isolates / 4. 7 % were most often found in milk and dairy products (14.6 %, while their prevalence in livestock was generally low (0-4 %. Of human isolates, 2.9 to 6.8 % had a non-wildtype phenotype. An association between reduced susceptibility to DDAC, high-level-aminoglycoside resistance and aminopenicillin resistance was seen in E. faecium (p In addition, bacteria (n = 42 of different genera were isolated from formic acid based boot bath disinfectant (20 ml of 55 % formic acid /l. The MICs of this disinfectant exceeded the wildtype MICs up to 20fold (staphylococci, but were still one to three orders of magnitude below the used concentration of the disinfectant (i. e. 1.1 % formic acid. In conclusion, the bacterial susceptibility to disinfectants still seems to be high. Thus, the proper use of disinfectants in livestock surroundings along with a good hygiene praxis should still be highly encouraged. Hints to a link between antibiotic resistance and reduced susceptibility for disinfectants – as seen for E. faecium - should be substantiated in further studies and might be an additional reason to confine the use of antibiotics.

Assessing the human health impacts of exposure to disinfection by-products--a critical review of concepts and methods.

Science.gov (United States)

Grellier, James; Rushton, Lesley; Briggs, David J; Nieuwenhuijsen, Mark J

2015-05-01

Understanding the public health implications of chemical contamination of drinking water is important for societies and their decision-makers. The possible population health impacts associated with exposure to disinfection by-products (DBPs) are of particular interest due to their potential carcinogenicity and their widespread occurrence as a result of treatments employed to control waterborne infectious disease. We searched the literature for studies that have attempted quantitatively to assess population health impacts and health risks associated with exposure to DBPs in drinking water. We summarised and evaluated these assessments in terms of their objectives, methods, treatment of uncertainties, and interpretation and communication of results. In total we identified 40 studies matching our search criteria. The vast majority of studies presented estimates of generic cancer and non-cancer risks based on toxicological data and methods that were designed with regulatory, health-protective purposes in mind, and therefore presented imprecise and biased estimates of health impacts. Many studies insufficiently addressed the numerous challenges to DBP risk assessment, failing to evaluate the evidence for a causal relationship, not appropriately addressing the complex nature of DBP occurrence as a mixture of chemicals, not adequately characterising exposure in space and time, not defining specific health outcomes, not accounting for characteristics of target populations, and not balancing potential risks of DBPs against the health benefits related with drinking water disinfection. Uncertainties were often poorly explained or insufficiently accounted for, and important limitations of data and methods frequently not discussed. Grave conceptual and methodological limitations in study design, as well as erroneous use of available dose-response data, seriously impede the extent to which many of these assessments contribute to understanding the public health implications of

Fingerprinting the reactive toxicity pathways of 50 drinking water disinfection by-products.

Science.gov (United States)

Stalter, Daniel; O'Malley, Elissa; von Gunten, Urs; Escher, Beate I

2016-03-15

A set of nine in vitro cellular bioassays indicative of different stages of the cellular toxicity pathway was applied to 50 disinfection by-products (DBPs) to obtain a better understanding of the commonalities and differences in the molecular mechanisms of reactive toxicity of DBPs. An Eschericia coli test battery revealed reactivity towards proteins/peptides for 64% of the compounds. 98% activated the NRf2-mediated oxidative stress response and 68% induced an adaptive stress response to genotoxic effects as indicated by the activation of the tumor suppressor protein p53. All DBPs reactive towards DNA in the E. coli assay and activating p53 also induced oxidative stress, confirming earlier studies that the latter could trigger DBP's carcinogenicity. The energy of the lowest unoccupied molecular orbital ELUMO as reactivity descriptor was linearly correlated with oxidative stress induction for trihalomethanes (r(2)=0.98) and haloacetamides (r(2)=0.58), indicating that potency of these DBPs is connected to electrophilicity. However, the descriptive power was poor for haloacetic acids (HAAs) and haloacetonitriles (r(2) (0.80, indicating that HAAs' potency is connected to both, electrophilicity and speciation. Based on the activation of oxidative stress response and the soft electrophilic character of most tested DBPs we hypothesize that indirect genotoxicity-e.g., through oxidative stress induction and/or enzyme inhibition-is more plausible than direct DNA damage for most investigated DBPs. The results provide not only a mechanistic understanding of the cellular effects of DBPs but the effect concentrations may also serve to evaluate mixture effects of DBPs in water samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

Science.gov (United States)

Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

2014-03-01

Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers. Copyright © 2013 Elsevier B.V. All rights reserved.

Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

Directory of Open Access Journals (Sweden)

Jorge Curiel-Esparza

2014-09-01

Full Text Available This paper presents an application of the Analytical Hierarchy Process (AHP by integrating a Delphi process for selecting the best sustainable disinfection technique for wastewater reuse projects. The proposed methodology provides project managers a tool to evaluate problems with multiple criteria and multiple alternatives which involve non-commeasurable decision criteria, with expert opinions playing a major role in the selection of these treatment technologies. Five disinfection techniques for wastewater reuse have been evaluated for each of the nine criteria weighted according to the opinions of consulted experts. Finally, the VIKOR method has been applied to determine a compromise solution, and to establish the stability of the results. Therefore, the expert system proposed to select the optimal disinfection alternative is a hybrid method combining the AHP with the Delphi method and the VIKOR technique, which is shown to be appropriate in realistic scenarios where multiple stakeholders are involved in the selection of a sustainable disinfection technique for wastewater reuse projects.

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

Directory of Open Access Journals (Sweden)

Andrade Denise de

2000-01-01

Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

Directory of Open Access Journals (Sweden)

Denise de Andrade

2000-03-01

Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

Energy Technology Data Exchange (ETDEWEB)

Li Hongna, E-mail: lihongna@gmail.com [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Zhu Xiuping [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Ni Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

2011-11-30

Highlights: > Electrochemical, O{sub 3}, NaClO and NH{sub 2}Cl were compared at respective optimal condition. > Disinfection efficacy was similar for different bacteria in electrolysis. > Harsh Bacillus was inactivated more difficult in O{sub 3}, NaClO and NH{sub 2}Cl system. > Efficient disinfection of electrolysis was attributed to nonselectivity of {center_dot}OH. > Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L{sup -1} for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

International Nuclear Information System (INIS)

Li Hongna; Zhu Xiuping; Ni Jinren

2011-01-01

Highlights: → Electrochemical, O 3 , NaClO and NH 2 Cl were compared at respective optimal condition. → Disinfection efficacy was similar for different bacteria in electrolysis. → Harsh Bacillus was inactivated more difficult in O 3 , NaClO and NH 2 Cl system. → Efficient disinfection of electrolysis was attributed to nonselectivity of ·OH. → Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L -1 for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments inactivation of the two

Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2009-06-15

Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg {center_dot} min{sup -1} showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process.

Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

International Nuclear Information System (INIS)

Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho

2009-01-01

Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg · min -1 showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process

9 CFR 91.18 - Cleaning and disinfection of transport carriers for export.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of transport....18 Cleaning and disinfection of transport carriers for export. All fittings, utensils and equipment... port. Such disinfection of halters, ropes, and similar equipment used in handling and tying of animals...

Do Iodine Contrast Media Compounds Used for Medical Imaging Contribute to the Formation of Iodinated Disinfection By-Products in Drinking Water?

Science.gov (United States)

Iodinated disinfection byproducts (DBPs) have recently gained attention due to their cyto- and genotoxicity and increased formation in drinking water treated with chloramine, which has become an increasingly popular disinfectant in the United States. One of these—iodoacetic acid...

Antibacterial efficacy of commercial disinfectants on dirt floor used in poultry breeder houses

Directory of Open Access Journals (Sweden)

F Pilotto

2007-06-01

Full Text Available Dirt floors are used on most Brazilian poultry farms since the construction of concrete floors is very expensive. In vitro tests carried out to verify the effectiveness of disinfectants do not consider the adverse conditions found in poultry farms. Therefore, the present study aimed at evaluating the effect of six commercial disinfectants on the reduction of total and fecal coliforms on the dirt floor of breeder houses. The amount of disinfectant solution to be used per square meter was defined by counting total and fecal coliforms at different soil depths and by analyzing soil physical properties. Coliforms were detected at 0.5 cm, and one liter of disinfectant solution was sufficient for soil saturation at this depth. After that, the efficacy of six commercial products (caustic soda, hydrated lime, phenols 1 and 2, iodine, glutaraldehyde, and quaternary ammonium in reducing the number of coliforms, after six hours of contact with the dirt floor, was assessed using the most probable number (MPN method. Escherichia coli specimens isolated from the dirt floor were used to evaluate in vitro effectiveness of disinfectants. Products that yielded the best results in the MPN method were also effective in the in vitro tests. Among the tested disinfectants, hydrated lime was the most efficient, reducing the initial contamination by 2.9 log after six hours of contact with the dirt floor.

Hand hygiene--evaluation of three disinfectant hand sanitizers in a community setting.

Directory of Open Access Journals (Sweden)

Rita Babeluk

Full Text Available Hand hygiene is acknowledged as the single most important measure to prevent nosocomial infections in the healthcare setting. Similarly, in non-clinical settings, hand hygiene is recognised as a key element in helping prevent the spread of infectious diseases. The aim of this study was to evaluate the efficacy of three different disinfectant hand sanitizers in reducing the burden of bacterial hand contamination in 60 healthy volunteers in a community setting, both before and after education about the correct use of hand sanitizers. The study is the first to evaluate the efficacy and ease of use of different formulations of hand rubs used by the general population. The products tested were: Sterillium (perfumed, liquid, desderman pure gel (odorless, gel and Lavit (perfumed, spray. Sterillium and desderman are EN1500 (hygienic hand rub certified products (available in pharmacy and Lavit is non EN1500 certified and available in supermarkets. The two EN1500 certified products were found to be significantly superior in terms of reducing bacterial load. desderman pure gel, Sterillium and Lavit reduced the bacterial count to 6.4%, 8.2% and 28.0% respectively. After education in the correct use of each hand rub, the bacterial load was reduced even further, demonstrating the value of education in improving hand hygiene. Information about the testers' perceptions of the three sanitizers, together with their expectations of a hand sanitizer was obtained through a questionnaire. Efficacy, followed by skin compatibility were found to be the two most important attributes of a hand disinfectant in our target group.

In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

Directory of Open Access Journals (Sweden)

Fahimeh Hamedi Rad

2010-12-01

Full Text Available Background and aims. The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods. Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and Deconex were selected and the impressions (n=108 were divided into four groups (n=24 and eight subgroups (n=12 for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12 was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were analyzed by descriptive methods (mean and standard deviation, t-test, two-way analysis of variance (ANOVA and Duncan test, using SPSS 14.0 software for windows. Results. The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the immersion method, respectively. Conclusion. Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10.

Resistance of Pseudomonas aeruginosa isolates to hydrogel contact lens disinfection correlates with cytotoxic activity.

Science.gov (United States)

Lakkis, C; Fleiszig, S M

2001-04-01

One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37 degrees C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22 degrees C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear.

Degradation kinetics of organic chloramines and formation of disinfection by-products during chlorination of creatinine.

Science.gov (United States)

Zhang, Tianyang; Xu, Bin; Wang, Anqi; Cui, Changzheng

2018-03-01

Organic chloramines can interfere with the measurement of effective combined chlorine in chlorinated water and are potential intermediate products of highly toxic disinfection by-products (DBPs). In order to know more about the degradation and transformation of organic chloramines, a typical organic chloramine precursor creatinine was selected for investigation and a corresponding individual organic chloramine chlorocreatinine was prepared in this study. The preparation condition of chlorocreatinine by chlorination was established as chlorine/creatinine = 1 M/M, reaction time = 2 h and pH = 7.0. Then the degradation kinetics of chlorocreatinine during further chlorination was studied, and a second-order rate constant of 1.16 (±0.14) M -1 s -1 was obtained at pH 7.0. Solution pH significantly influenced the degradation rate, and the elementary rate constants of chlorocreatinine with HOCl+H + , HOCl, OCl - and chlorocreatinine - with OCl - were calculated as 2.43 (±1.55) × 10 4  M -2  s -1 , 1.05 (±0.09) M -1 s -1 , 2.86 (±0.30) M -1 s -1 and 3.09 (±0.24) M -1 s -1 , respectively. Besides, it was found that chlorocreatinine could be further converted into several C-DBPs (chloroform and trichloroacetone) and N-DBPs (dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM)) during chlorination. The total yield of DBPs increased obviously with increasing pH, especially for TCNM. In addition, the presence of humic acid in creatinine solution could increase the formation of DCAN obviously during chlorination. Based on the UPLC-Q-TOF-MS analysis, the conversion pathways of chlorocreatinine were proposed. Several kinds of intermediate products were also identified as organic chloramines and some of them could even exist stably during the further chlorination. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Disinfecting Potential of Contact Lens Soutions used by Sultan Qaboos University Students

Science.gov (United States)

Nzeako, B. C.; Al-Sumri, Sara H.

2011-01-01

Objectives: This study aimed to determine the disinfecting potential of some contact lens solutions used by some university students in Oman. Methods: This work was carried out from January to June 2010 in the Department of Microbiology & Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Oman. Fifty disinfecting solutions, in which contact lenses were disinfected according to the manufacturers’ instructions, were collected from the students and plated on various microbiological culture media. Bacterial isolates were identified by API-20E, API-20NE and Phoenix automated systems while fungi were identified by their cultural characteristics and biochemistry. Results: From 98 isolates, Pseudomonas aeruginosa was 23.5%; Penicillium, 13%; Candida species, 9.2%; coagulase negative staphylococci, 9.2%; Serratia marcescens, 6.1%; Bacillus, 5.1%; Aspergillus flavus, 5.1%; Serratia liquefaciens, Pseudomonas fluorescens, Enterobacter cloacae and Aspergillus niger, 4.1% each; Chryseomonas luteola and Chryseomonas indologenes, 3.1% each; Stenotrophomonas maltophilia, Serratia odorifera, 2.0% each; Enterobacter aerogenes and Klebsiella pneumoniae, 1% each. Most isolates (65%) came from polyhexanide containing solutions. Conclusion: Contact lens disinfecting solutions with the same formulations, but manufactured by different companies, possessed different disinfecting potentials. PMID:21969898

Chloraminated Concentrated Drinking Water for Disinfection Byproduct Mixtures Research: Evaluating Free Chlorine Contact Times

Science.gov (United States)

Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) present in the source water. Since 1974, over 600 DBPs have been identified in drinking water, yet a large portio...

Chloramination of Concentrated Drinking Water: Evaluation of Disinfection Byproduct Formation and Dosing Scenarios - Portland

Science.gov (United States)

Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

Chemical cleaning/disinfection and ageing of organic UF membranes: a review.

Science.gov (United States)

Regula, C; Carretier, E; Wyart, Y; Gésan-Guiziou, G; Vincent, A; Boudot, D; Moulin, P

2014-06-01

Membrane separation processes have become a basic unit operation for process design and product development. These processes are used in a variety of separation and concentration steps, but in all cases, the membranes must be cleaned regularly to remove both organic and inorganic material deposited on the surface and/or into the membrane bulk. Cleaning/disinfection is a vital step in maintaining the permeability and selectivity of the membrane in order to get the plant to its original capacity, to minimize risks of bacteriological contamination, and to make acceptable products. For this purpose, a large number of chemical cleaning/disinfection agents are commercially available. In general, these cleaning/disinfection agents have to improve the membrane flux to a certain extent. However, they can also cause irreversible damages in membrane properties and performances over the long term. Until now, there is considerably less literature dedicated to membrane ageing than to cleaning/disinfection. The knowledge in cleaning/disinfection efficiency has recently been improved. But in order to develop optimized cleaning/disinfection protocols there still remains a challenge to better understand membrane ageing. In order to compensate for the lack of correlated cleaning/disinfection and ageing data from the literature, this paper investigates cleaning/disinfection efficiencies and ageing damages of organic ultrafiltration membranes. The final aim is to provide less detrimental cleaning/disinfection procedures and to propose some guidelines which should have been taken into consideration in term of membrane ageing studies. To carry out this study, this article will detail the background of cleaning/disinfection and aging membrane topics in a first introductive part. In a second part, key factors and endpoints of cleaning/disinfection and aging membranes will be discussed deeply: the membrane role and the cleaning parameters roles, such as water quality, storing conditions

An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

Science.gov (United States)

Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

2013-05-01

OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

Disinfection of sewage sludge by gamma radiation, electron beams and alternative methods

International Nuclear Information System (INIS)

Lessel, T.

1997-01-01

Sewage sludges generally contain high concentrations of pathogens, even after digestion or other conventional treatments for stabilization. Disinfection can be effected by irradiation (e.g. gamma or electron beam), by heat treatment (pasteurization or thermophilic stabilization), and by changing the pH (lime treatment). Irradiation is a simple and reliable process for disinfection with special advantages and favorable side-effects. Irradiation can be combined with oxygenation, heat or other treatments, with favorable synergistic effects. The total costs for the irradiation treatment of sewage sludges are comparable to those of alternative disinfection methods. Most of the worldwide practical experience has been obtained at the sewage-sludge irradiation plant in Geiselbullach (10 km west of Munich, Germany), which was continuously in operation from 1973 to 1993. A multidisciplinary research programme was conducted during the first 8 years. In subsequent years, the plant was operated commercially for sewage-sludge disinfection, without public funds. Other demonstration or research plants for sewage-sludge irradiation have been reported in the USA, India, Russia, Japan, Austria, Germany and Hungary. (author)

Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

Science.gov (United States)

Kilvington, Simon; Winterton, Lynn

2017-11-01

Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

Effectiveness of cleaning-disinfection wipes and sprays against multidrug-resistant outbreak strains.

Science.gov (United States)

Kenters, Nikki; Huijskens, Elisabeth G W; de Wit, Sophie C J; van Rosmalen, Joost; Voss, Andreas

2017-08-01

Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and disinfection were compared, using 2 different application methods. The aim was to determine which product was most effective in simultaneous cleaning and disinfection of surfaces. Seven cleaning-disinfecting wipes and sprays based on different active ingredients were tested for their efficacy in removal of microbial burden and proteins. Efficacy was tested with known Dutch outbreak strains: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, or Acinetobacter baumannii. For all bacteria, ready-to-use cleaning-disinfecting products reduced the microbial count with a log 10 reduction >5 with a 5-minute exposure time, with the exception of a spray based on hydrogen peroxide. Omitting the aforementioned hydrogen peroxide spray, there were no significant differences between use of a wipe or spray in bacterial load reduction. Using adenosine triphosphate (ATP) measurements, a significant difference in log 10 relative light units (RLU) reduction between various bacteria (P ≤ .001) was observed. In general, a >5 log 10 reduction of colony forming units (CFU) for tested wipes and sprays was obtained for all tested bacteria strains, with exception of hydrogen peroxide spray and VRE. Although ATP may show a difference between pre- and postcleaning, RLU reduction does not correlate with actual CFU reductions. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Hand Hygiene – Evaluation of Three Disinfectant Hand Sanitizers in a Community Setting

Science.gov (United States)

Babeluk, Rita; Jutz, Sabrina; Mertlitz, Sarah; Matiasek, Johannes; Klaus, Christoph

2014-01-01

Hand hygiene is acknowledged as the single most important measure to prevent nosocomial infections in the healthcare setting. Similarly, in non-clinical settings, hand hygiene is recognised as a key element in helping prevent the spread of infectious diseases. The aim of this study was to evaluate the efficacy of three different disinfectant hand sanitizers in reducing the burden of bacterial hand contamination in 60 healthy volunteers in a community setting, both before and after education about the correct use of hand sanitizers. The study is the first to evaluate the efficacy and ease of use of different formulations of hand rubs used by the general population. The products tested were: Sterillium (perfumed, liquid), desderman pure gel (odorless, gel) and Lavit (perfumed, spray). Sterillium and desderman are EN1500 (hygienic hand rub) certified products (available in pharmacy) and Lavit is non EN1500 certified and available in supermarkets. The two EN1500 certified products were found to be significantly superior in terms of reducing bacterial load. desderman pure gel, Sterillium and Lavit reduced the bacterial count to 6.4%, 8.2% and 28.0% respectively. After education in the correct use of each hand rub, the bacterial load was reduced even further, demonstrating the value of education in improving hand hygiene. Information about the testers' perceptions of the three sanitizers, together with their expectations of a hand sanitizer was obtained through a questionnaire. Efficacy, followed by skin compatibility were found to be the two most important attributes of a hand disinfectant in our target group. PMID:25379773

Epigenetic regulation of non-lymphoid cells by Bisphenol-A, a model endocrine disrupter: Potential Implications for Immunoregulation

Directory of Open Access Journals (Sweden)

Deena eKhan

2015-06-01

Full Text Available Endocrine disrupting chemicals (EDC abound in the environment since many compounds are released from chemical, agricultural, pharmaceutical and consumer product industries. Many of the EDCs such as Bisphenol A (BPA have estrogenic activity or interfere with endogenous sex hormones. Experimental studies have reported a positive correlation of BPA with reproductive toxicity, altered growth and immune dysregulation. Although the precise relevance of these studies to the environmental levels is unclear, nevertheless, their potential health implications remain a concern. One possible mechanism by which BPA can alter genes is by regulating epigenetics, including microRNA, alteration of methylation and histone acetylation. There is now wealth of information on BPA effects on non-lymphoid cells and by comparison, paucity of data on effects of BPA on the immune system. In this mini review, we will highlight BPA regulation of estrogen receptor-mediated immune cell functions and in different inflammatory conditions. In addition, BPA-mediated epigenetic regulation of non-lymphoid cells is emphasized. We recognize that most of these studies are on non-lymphoid cells, and given that BPA also affects the immune system, it is plausible that BPA could have similar epigenetic regulation in immune cells. It is hoped that this review will stimulate studies in this area to ascertain whether or not BPA epigenetically regulates the cells of the immune system.

Antiviral activity of a novel composition of peracetic acid disinfectant on parvoviruses

Science.gov (United States)

Dagher, Fadi; Jiang, Jun; Tijssen, Peter; Laliberté, Jean-François

2017-01-01

Porcine parvoviruses (PPV) are known to be particularly resistant to many disinfectants used to control other non-enveloped viruses. However, effective disinfectants used against PPV are harsh and corrosive to animal health facilities and the environment. We propose a noncorrosive “green” disinfectant that generates peracetic acid in-situ and is capable of inactivating PPV completely at a 1% concentration for a 10-minute contact time. PMID:28154460

Bench-Scale Evaluation of Peracetic Acid and Twin Oxide ™ as Disinfectants in Drinking Water

Science.gov (United States)

Chlorine is widely used as an inexpensive and potent disinfectant in the United States for drinking water. However, chlorine has the potential for forming carcinogenic and mutagenic disinfection by-products (DBPs). In this study, bench scale experiments were conducted at the U.S...

Prevention of microbial species introductions to the Arctic: The efficacy of footwear disinfection measures on cruise ships

Directory of Open Access Journals (Sweden)

Sabine B. Rumpf

2018-03-01

Full Text Available Biosecurity measures are commonly used to prevent the introduction of non-native species to natural environments globally, yet the efficacy of practices is rarely tested under operational conditions. A voluntary biosecurity measure was trialled in the Norwegian high Arctic following concern that non-native species might be transferred to the region on the footwear of travellers. Passengers aboard an expedition cruise ship disinfected their footwear with the broad spectrum disinfectant Virkon S prior to and in-between landing at sites around the remote Svalbard archipelago. The authors evaluated the efficacy of simply stepping through a disinfectant foot bath, which is the most common practice of footwear disinfection aboard expedition cruise ships in the Arctic. This was compared to a more time consuming and little-used method involving drying disinfected footwear, as proposed by other studies. The two practices were evaluated by measuring microbial growth on paired footwear samples before and after disinfection under both conditions. Step-through disinfection did not substantially reduce microbial growth on the footwear. Allowing disinfected footwear to dry, however, reduced the microbial burden significantly to lower levels. Thus, the currently adopted procedures used aboard ships are ineffective at removing microbial burden and are only effective when footwear is given more time to dry than currently granted under operational conditions. These findings underscore results from empirical research performed elsewhere and suggest the need to better relay this information to practitioners. It is suggested that footwear should minimally be wiped dry after step-through disinfection as a reasonable compromise between biosecurity and practicability.

Effect of BioSentry 904 and ethylenediaminetetraacetic acid-tris disinfecting during incubation of chicken eggs on microbial levels and productivity of poultry.

Science.gov (United States)

Walker, S E; Sander, J E

2004-01-01

Proper sanitation practices and the use of efficacious disinfectants in a hatchery have an effect on chick quality. Aerosol bacterial counts, egg moisture loss, hatchability, chick quality, and broiler productivity were evaluated when egg surfaces were contaminated by immersion of each egg into a broth medium containing a field isolate of Pseudomonas aeruginosa and incubated with exposure to one of three disinfectant treatments administered by fine spray: distilled water, BioSentry 904 (904), and a 1:1 ratio of 904 and ethylenediaminetetraacetic acid (EDTA)-Tris. The aerosol bacteria levels were statistically greater on day 21 of incubation in the group treated with distilled water than in those receiving disinfectants. Overall hatch of fertile eggs and egg moisture loss were comparable among all three treatments. At 1 day of age, the chicks incubated with 904 had a statistically lower yolk sac contamination rate than those incubated with 904+EDTA-Tris or distilled water. The 2-wk mortality rates, body weights, feed conversion ratios, yolk sac weights, and yolk sac contamination rates were all similar among the three treatments.

Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals.

Science.gov (United States)

Boyce, John M

2016-01-01

Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer's recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid) and cold atmospheric pressure plasma show potential for use in hospitals. Creating "self-disinfecting" surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer "no-touch" (automated) decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C) light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm) light. These "no-touch" technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections. In conclusion, continued efforts to

Comparative Virucidal Efficacy of Seven Disinfectants Against Murine Norovirus and Feline Calicivirus, Surrogates of Human Norovirus.

Science.gov (United States)

Zonta, William; Mauroy, Axel; Farnir, Frederic; Thiry, Etienne

2016-03-01

Human noroviruses (HuNoV) are the leading cause of acute non-bacterial gastroenteritis in humans and can be transmitted either by person-to-person contact or by consumption of contaminated food. A knowledge of an efficient disinfection for both hands and food-contact surfaces is helpful for the food sector and provides precious information for public health. The aim of this study was to evaluate the effect of seven disinfectants belonging to different groups of biocides (alcohol, halogen, oxidizing agents, quaternary ammonium compounds, aldehyde and biguanide) on infectious viral titre and on genomic copy number. Due to the absence of a cell culture system for HuNoV, two HuNoV surrogates, such as murine norovirus and feline calicivirus, were used and the tests were performed in suspension, on gloves and on stainless steel discs. When, as criteria of efficacy, a log reduction >3 of the infectious viral titre on both surrogates and in the three tests is used, the most efficacious disinfectants in this study appear to be biocidal products B, C and D, representing the halogens, the oxidizing agents group and a mix of QAC, alcohol and aldehyde, respectively. In addition, these three disinfectants also elicited a significant effect on genomic copy number for both surrogate viruses and in all three tests. The results of this study demonstrate that a halogen compound, oxidizing agents and a mix of QAC, alcohol and aldehyde are advisable for HuNoV disinfection of either potentially contaminated surfaces or materials in contact with foodstuffs.

Estimating retrospective exposure of household humidifier disinfectants.

Science.gov (United States)

Park, D U; Friesen, M C; Roh, H S; Choi, Y Y; Ahn, J J; Lim, H K; Kim, S K; Koh, D H; Jung, H J; Lee, J H; Cheong, H K; Lim, S Y; Leem, J H; Kim, Y H; Paek, D M

2015-12-01

We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant, and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m(3)) was estimated based on the disinfectant volume (ml) and frequency added to the humidifier per day, disinfectant bulk level (μg/ml), the volume of the room (m(3)) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration, and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤6 years old. Further study is underway to evaluate the association between the disinfectant exposures estimated here with clinically diagnosed lung disease. Retrospective exposure to household humidifier disinfectant as estimated here can be used to evaluate associations with clinically diagnosed lung disease due to the use of humidifier disinfectant in Korea. The framework, with modifications to account for dispersion and use patterns, can also be potentially adapted to assessment of other household chemical exposures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

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V. V. Kuzin

2018-01-01

Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

Ultraviolet disinfection of treated municipal wastewaters

Energy Technology Data Exchange (ETDEWEB)

Vander Laan, H; Cairns, B

1993-12-31

A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

Comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: Effects of suspended-solids and pH.

Science.gov (United States)

McFadden, M; Loconsole, J; Schockling, A J; Nerenberg, R; Pavissich, J P

2017-12-01

Peracetic acid (PAA) is an alternative disinfectant that may be effective for combined sewer overflow (CSO) disinfection, but little is known about the effect of particle size on PAA disinfection efficiency. In this work, PAA and hypochlorite were compared as disinfectants, with a focus on the effect of wastewater particles. Inactivation experiments were conducted on suspended cultures of Escherichia coli and wastewater suspended solids. Tested size fractions included particle diameters disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PAA disinfection. The PAA disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PAA disinfection leaves most cells in a viable but non-culturable condition. Fourier transform infrared spectroscopy (FTIR) analyses suggests that PAA and hypochlorite may inactivate E. coli bacteria by similar mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of a stirred tank electrochemical cell for water disinfection processes

International Nuclear Information System (INIS)

Polcaro, A.M.; Vacca, A.; Mascia, M.; Palmas, S.; Pompei, R.; Laconi, S.

2007-01-01

Laboratory experiments were performed to characterize the behaviour of an electrochemical cell equipped with boron-doped diamond anodes and to verify its effectiveness in water disinfection. The hydrodynamic regime was determined when the cell worked either in batch or in continuous mode. Galvanostatic electrolyses of aqueous 1 mM Na 2 SO 4 solutions were performed to investigate on the oxidant production in different experimental conditions. The same solutions contaminated by E. coli, enterococci and coliforms were used as test media to verify the effectiveness of the system in the disinfection process. Experimental results indicated that the major inactivation mechanism of bacteria in the electrochemical cell is a disinfection by electrochemically generated oxidants, however a cooperative effect of superficial reaction has to be taken into account. The great capability of BDD anode to produce reactive oxygen species (ROS) and other oxidizing species during the electrolysis allows to establish a chlorine-free disinfection process

Precursors of nitrogenous disinfection by-products in drinking water--A critical review and analysis

Energy Technology Data Exchange (ETDEWEB)

Bond, Tom [Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Templeton, Michael R.; Graham, Nigel [Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom)

2012-10-15

Highlights: Black-Right-Pointing-Pointer The proportion of N-DBP formation attributable to specific precursors was calculated. Black-Right-Pointing-Pointer Precursor concentrations are typically insufficient to account for observed N-DBP formation, except CNX and NDMA. Black-Right-Pointing-Pointer Amino acid precursors are easier to remove during water treatment than suggested by laboratory studies. - Abstract: In recent years research into the formation of nitrogenous disinfection by-products (N-DBPs) in drinking water - including N-nitrosodimethylamine (NDMA), the haloacetonitriles (HANs), haloacetamides (HAcAms), cyanogen halides (CNX) and halonitromethanes (HNMs) - has proliferated. This is partly due to their high reported toxicity of N-DBPs. In this review paper information about the formation yields of N-DBPs from model precursors, and about environmental precursor occurrence, has been employed to assess the amount of N-DBP formation that is attributable to known precursors. It was calculated that for HANs and HAcAms, the concentrations of known precursors - mainly free amino acids are insufficient to account for the observed concentrations of these N-DBP groups. However, at least in some waters, a significant proportion of CNX and NDMA formation can be explained by known precursors. Identified N-DBP precursors tend to be of low molecular weight and low electrostatic charge relative to bulk natural organic matter (NOM). This makes them recalcitrant to removal by water treatment processes, notably coagulation, as confirmed by a number of bench-scale studies. However, amino acids have been found to be easier to remove during water treatment than would be suggested by the known molecular properties of the individual free amino acids.

Characterization of soluble microbial products as precursors of disinfection byproducts in drinking water supply.

Science.gov (United States)

Liu, Jin-Lin; Li, Xiao-Yan; Xie, Yue-Feng; Tang, Hao

2014-02-15

Water pollution by wastewater discharge can cause the problem of disinfection byproducts (DBPs) in drinking water supply. In this study, DBP formation characteristics of soluble microbial products (SMPs) as the main products of wastewater organic biodegradation were investigated. The results show that SMPs can act as DBP precursors in simulated wastewater biodegradation process. Under the experimental conditions, stabilized SMPs had DBPFP (DBP formation potential) yield of around 5.6 μmol mmol(-1)-DOC (dissolved organic carbon) and DBP speciation profile different from that of the conventional precursor, natural organic matter (NOM). SMPs contained polysaccharides, proteins, and humic-like substances, and the latter two groups can act as reactive DBP precursors. SMP fraction with molecular weight of water treatment processes, more efforts are needed to control wastewater-derived DBP problem in water resource management. Copyright © 2013 Elsevier B.V. All rights reserved.

Efficacy of cleaning and disinfection procedures in a zebrafish (Danio rerio) facility.

Science.gov (United States)

Garcia, Rachel L; Sanders, George E

2011-11-01

Appropriate cleaning and disinfection procedures in zebrafish (Danio rerio) laboratories are crucial in preventing the spread of aquatic animal pathogens and minimizing the build-up of waste products and biologic matter. The procedures selected should accomplish these goals and incorporate the individual needs of various laboratories. In this study of a single zebrafish facility, we assessed the efficacy of 2 different cleaning and disinfection procedures for nets, tanks, and lids. ATP levels were used as a surrogate biomarker for microbial burden. We measured the number of relative light units (RLU), as an expression of the amount of ATP present, on items before and after disinfection and calculated the percentage reduction. We compared daily replacement of a commercial net disinfection product in J lab with weekly replacement in H lab and found a 96.6% reduction in RLU in H lab and a 91.2% reduction in J lab. These results indicate that either replacement schedule is effective. Evaluation of tanks and lids soaked in a bleach disinfection bath for 30 or 60 min revealed a 99.7% reduction in RLU at 30 min compared with 97.1% at 60 min. Therefore a 30-min soak in a bleach bath achieved a similar level of disinfection as did a 60-min soak. The current results demonstrate that these cleaning and disinfection methods are efficacious.

Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals

Directory of Open Access Journals (Sweden)

John M. Boyce

2016-04-01

Full Text Available Abstract Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer’s recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid and cold atmospheric pressure plasma show potential for use in hospitals. Creating “self-disinfecting” surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer “no-touch” (automated decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm light. These “no-touch” technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections

UV disinfection in drinking water supplies.

Science.gov (United States)

Hoyer, O

2000-01-01

UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

Directory of Open Access Journals (Sweden)

Negar Rezania

2013-01-01

Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

Disinfection Contact Time study plan (100-N Area tracer protocol). Revision 1

International Nuclear Information System (INIS)

Kretzschmar, S.P.; Bedi, G.S.; Martinez, P.; Ervin, K.

1996-07-01

Bechtel Hanford, Inc. will prepare an Engineering Tracer Study Protocol for the determination of contact time for the disinfection process at Group A Non-transient Non-community water treatment plant for the 100-N Water Plant at the Hanford Site in Richland, Washington. Included in this report are the results of a study that determine the actual detention time within the plant clearwell, and thus the disinfection contact time at several clearwell effluent flow rates

Disinfection by-product formation during chlor(am)ination of algal organic matters (AOM) extracted from Microcystis aeruginosa: effect of growth phases, AOM and bromide concentration.

Science.gov (United States)

Chen, Juxiang; Gao, Naiyun; Li, Lei; Zhu, Mingqiu; Yang, Jing; Lu, Xian; Zhang, Yansen

2017-03-01

Algae organic matter (AOM), including extracellular organic matter (EOM) and intracellular organic matter (IOM), has caused a series of problems to the water quality, among which formation of disinfection by-products (DBPs) during subsequent chlor(am)ination process was especially serious and concerned. This study characterized physicochemical properties of the EOM and IOM solution extracted from different growth phases of Microcystis aeruginosa and investigated the corresponding formation potential of DBPs during chlor(am)ination process. Besides, the effects of initial concentration of xEOM, IOM, and Br - on the yields of disinfection by-product formation potential were studied. The results indicated that the specific UV absorbance (SUVA 254 ) values of IOM and EOM (1.09 and 2.66 L/mg m) were considerably lower than that of natural organic matter (NOM) (4.79 L/mg m). Fluorescence dates showed the soluble microbial by-product was dominant in both EOM and IOM, and the tryptophan was the main component of AOM. From the excitation-emission matrix figure of EOM and IOM, we found that the content of the high molecular weight protein substance in IOM was higher than EOM. During chlorination of EOM and IOM, the yields of four kinds of DBPs followed the order trichloroethene (TCM) > 1,1-DCP > dichloride acetonitrile (DCAN) > trichloronitromethane (TCNM), while the order was TCM > DCAN > TCNM > 1,1-DCP during chloramination process. The bromine substitution factor (BSF) value increased with the increasing of the concentration of Br - . When the concentration of Br - was 500 μg/L, the BSF values of chlorination EOM and IOM were 51.1 and 68.4%, respectively. As the concentration of Br - increased, the formation of Cl-DBPs was inhibited and the formation of Br-DBPs was promoted. Graphical abstract ᅟ.

Radiological Impacts and Regulation of Rare Earth Elements in Non-Nuclear Energy Production

Directory of Open Access Journals (Sweden)

Timothy Ault

2015-03-01

Full Text Available Energy industries account for a significant portion of total rare earth usage, both in the US and worldwide. Rare earth minerals are frequently collocated with naturally occurring radioactive material, imparting an occupational radiological dose during recovery. This paper explores the extent to which rare earths are used by various non-nuclear energy industries and estimates the radiological dose which can be attributed to these industries on absolute and normalized scales. It was determined that typical rare earth mining results in an occupational collective dose of approximately 0.0061 person-mSv/t rare earth elements, amounting to a total of 330 person-mSv/year across all non-nuclear energy industries (about 60% of the annual collective dose from one pressurized water reactor operated in the US, although for rare earth mining the impact is spread out over many more workers. About half of the collective dose from non-nuclear energy production results from use of fuel cracking catalysts for oil refining, although given the extent of the oil industry, it is a small dose when normalized to the energy equivalent of the oil that is used annually. Another factor in energy industries’ reliance on rare earths is the complicated state of the regulation of naturally occurring radiological materials; correspondingly, this paper also explores regulatory and management implications.

Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

NARCIS (Netherlands)

Kenters, N.; E. Huijskens (Elisabeth); de Wit, S.C.J.; Sanders, I.G.J.M.; J.M. van Rosmalen (Joost); E. Kuijper; Voss, A.

2017-01-01

textabstractBackground: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested

Surface Dielectric Barrier Discharge Jet for Skin Disinfection

Science.gov (United States)

Creyghton, Yves; Meijer, Rogier; Verweij, Paul; van der Zanden, Frank; Leenders, Paul

A consortium consisting of the research institute TNO, the medical ­university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and potential ­standardization for plasma based disinfection procedures. The present paper describes technical progress in plasma source development together with initial microbiological data. Particular properties of the sheet shaped plasma volume are the possibility of treating large irregular surfaces in a short period of time, effective plasma produced species transfer to the surface together with high controllability of the nature of plasma species by means of temperature conditioning.

Spiral-shaped disinfection reactors

KAUST Repository

Ghaffour, NorEddine; Ait-Djoudi, Fariza; Naceur, Wahib Mohamed; Soukane, Sofiane

2015-01-01

This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body

Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

NARCIS (Netherlands)

Kenters, N.; Huijskens, E.G.; Wit, S.C.J. de; Sanders, I.; Rosmalen, J. van; Kuijper, E.J.; Voss, A.

2017-01-01

BACKGROUND: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested for their

Improving stethoscope disinfection at a children's hospital.

Science.gov (United States)

Zaghi, Justin; Zhou, Jing; Graham, Dionne A; Potter-Bynoe, Gail; Sandora, Thomas J

2013-11-01

Stethoscopes are contaminated with pathogenic bacteria and pose a risk for transmission of infections, but few clinicians disinfect their stethoscope after every use. We sought to improve stethoscope disinfection rates among pediatric healthcare providers by providing access to disinfection materials and visual reminders to disinfect stethoscopes. Prospective intervention study. Inpatient units and emergency department of a major pediatric hospital. Physicians and nurses with high anticipated stethoscope use. Baskets filled with alcohol prep pads and a sticker reminding providers to regularly disinfect stethoscopes were installed outside of patient rooms. Healthcare providers' stethoscope disinfection behaviors were directly observed before and after the intervention. Multivariable logistic regression models were created to identify independent predictors of stethoscope disinfection. Two hundred twenty-six observations were made in the preintervention period and 261 in the postintervention period (83% were of physicians). Stethoscope disinfection compliance increased significantly from a baseline of 34% to 59% postintervention (P stethoscope disinfection supplies and visible reminders outside of patient rooms significantly increased stethoscope disinfection rates among physicians and nurses at a children's hospital. This simple intervention could be replicated at other healthcare facilities. Future research should assess the impact on patient infections.

Baby bottle steam sterilizers disinfect home nebulizers inoculated with bacterial respiratory pathogens.

Science.gov (United States)

Towle, Dana; Callan, Deborah A; Farrel, Patricia A; Egan, Marie E; Murray, Thomas S

2013-09-01

Contaminated nebulizers are a potential source of bacterial infection but no single method is universally accepted for disinfection. We hypothesized that baby-bottle steam sterilizers effectively disinfect home nebulizers. Home nebulizers were inoculated with the common CF respiratory pathogens methicillin resistant Staphylococcus aureus, Burkholderia cepacia, Haemophilus influenzae, mucoid and non mucoid Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The nebulizers were swabbed for bacterial growth, treated with either the AVENT (Philips), the NUK Quick & Ready (Gerber) or DRY-POD (Camera Baby) baby bottle steam sterilizer and reswabbed for bacterial growth. All steam sterilizers were effective at disinfecting all home nebulizers. Viable bacteria were not recovered from any inoculated site after steam treatment, under any conditions tested. Steam treatment is an effective disinfection method. Additional studies are needed to confirm whether these results are applicable to the clinical setting. Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Precursors of nitrogenous disinfection by-products in drinking water––A critical review and analysis

International Nuclear Information System (INIS)

Bond, Tom; Templeton, Michael R.; Graham, Nigel

2012-01-01

Highlights: ► The proportion of N-DBP formation attributable to specific precursors was calculated. ► Precursor concentrations are typically insufficient to account for observed N-DBP formation, except CNX and NDMA. ► Amino acid precursors are easier to remove during water treatment than suggested by laboratory studies. - Abstract: In recent years research into the formation of nitrogenous disinfection by-products (N-DBPs) in drinking water – including N-nitrosodimethylamine (NDMA), the haloacetonitriles (HANs), haloacetamides (HAcAms), cyanogen halides (CNX) and halonitromethanes (HNMs) – has proliferated. This is partly due to their high reported toxicity of N-DBPs. In this review paper information about the formation yields of N-DBPs from model precursors, and about environmental precursor occurrence, has been employed to assess the amount of N-DBP formation that is attributable to known precursors. It was calculated that for HANs and HAcAms, the concentrations of known precursors – mainly free amino acids are insufficient to account for the observed concentrations of these N-DBP groups. However, at least in some waters, a significant proportion of CNX and NDMA formation can be explained by known precursors. Identified N-DBP precursors tend to be of low molecular weight and low electrostatic charge relative to bulk natural organic matter (NOM). This makes them recalcitrant to removal by water treatment processes, notably coagulation, as confirmed by a number of bench-scale studies. However, amino acids have been found to be easier to remove during water treatment than would be suggested by the known molecular properties of the individual free amino acids.

The effect of various disinfectants on detection of avian influenza virus by real time RT-PCR.

Science.gov (United States)

Suarez, D L; Spackman, E; Senne, D A; Bulaga, L; Welsch, A C; Froberg, K

2003-01-01

An avian influenza (AI) real time reverse transcriptase-polymerase chain reaction (RRT-PCR) test was previously shown to be a rapid and sensitive method to identify AI virus-infected birds in live-bird markets (LBMs). The test can also be used to identify avian influenza virus (AIV) from environmental samples. Consequently, the use of RRT-PCR was being considered as a component of the influenza eradication program in the LBMs to assure that each market was properly cleaned and disinfected before allowing the markets to be restocked. However, the RRT-PCR test cannot differentiate between live and inactivated virus, particularly in environmental samples where the RRT-PCR test potentially could amplify virus that had been inactivated by commonly used disinfectants, resulting in a false positive test result. To determine whether this is a valid concern, a study was conducted in three New Jersey LBMs that were previously shown to be positive for the H7N2 AIV. Environmental samples were collected from all three markets following thorough cleaning and disinfection with a phenolic disinfectant. Influenza virus RNA was detected in at least one environmental sample from two of the three markets when tested by RRT-PCR; however, all samples were negative by virus isolation using the standard egg inoculation procedure. As a result of these findings, laboratory experiments were designed to evaluate several commonly used disinfectants for their ability to inactivate influenza as well as disrupt the RNA so that it could not be detected by the RRT-PCR test. Five disinfectants were tested: phenolic disinfectants (Tek-trol and one-stroke environ), a quaternary ammonia compound (Lysol no-rinse sanitizer), a peroxygen compound (Virkon-S), and sodium hypochlorite (household bleach). All five disinfectants were effective at inactivating AIV at the recommended concentrations, but AIV RNA in samples inactivated with phenolic and quaternary ammonia compounds could still be detected by RRT

Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

DEFF Research Database (Denmark)

Olsen, R.; Kudirkiene, E.; Thofner, I.

2017-01-01

Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study...... was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted...... to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under...

Use of UV-C radiation to disinfect non-critical patient care items: a laboratory assessment of the Nanoclave Cabinet

Directory of Open Access Journals (Sweden)

Moore Ginny

2012-08-01

Full Text Available Abstract Background The near-patient environment is often heavily contaminated, yet the decontamination of near-patient surfaces and equipment is often poor. The Nanoclave Cabinet produces large amounts of ultraviolet-C (UV-C radiation (53 W/m2 and is designed to rapidly disinfect individual items of clinical equipment. Controlled laboratory studies were conducted to assess its ability to eradicate a range of potential pathogens including Clostridium difficile spores and Adenovirus from different types of surface. Methods Each test surface was inoculated with known levels of vegetative bacteria (106 cfu/cm2, C. difficile spores (102-106 cfu/cm2 or Adenovirus (109 viral genomes, placed in the Nanoclave Cabinet and exposed for up to 6 minutes to the UV-C light source. Survival of bacterial contaminants was determined via conventional cultivation techniques. Degradation of viral DNA was determined via PCR. Results were compared to the number of colonies or level of DNA recovered from non-exposed control surfaces. Experiments were repeated to incorporate organic soils and to compare the efficacy of the Nanoclave Cabinet to that of antimicrobial wipes. Results After exposing 8 common non-critical patient care items to two 30-second UV-C irradiation cycles, bacterial numbers on 40 of 51 target sites were consistently reduced to below detectable levels (≥ 4.7 log10 reduction. Bacterial load was reduced but still persisted on other sites. Objects that proved difficult to disinfect using the Nanoclave Cabinet (e.g. blood pressure cuff were also difficult to disinfect using antimicrobial wipes. The efficacy of the Nanoclave Cabinet was not affected by the presence of organic soils. Clostridium difficile spores were more resistant to UV-C irradiation than vegetative bacteria. However, two 60-second irradiation cycles were sufficient to reduce the number of surface-associated spores from 103 cfu/cm2 to below detectable levels. A 3 log10 reduction in

[Complex technology for water and wastewater disinfection and its industrial realization in prototype unit].

Science.gov (United States)

Arakcheev, E N; Brunman, V E; Brunman, M V; Konyashin, A V; Dyachenko, V A; Petkova, A P

Usage of complex automated electrolysis unit for drinking water disinfection and wastewater oxidation and coagulation is scoped, its ecological and energy efficiency is shown. Properties of technological process of anolyte production using membrane electrolysis of brine for water disinfection in municipal pipelines and potassium ferrate production using electrochemical dissolution of iron anode in NaOH solution for usage in purification plants are listed. Construction of modules of industrial prototype for anolyte and ferrate production and applied aspects of automation of complex electrolysis unit are proved. Results of approbation of electrolytic potassium ferrate for drinking water disinfection and wastewater, rain water and environmental water oxidation and coagulation are shown.

9 CFR 53.6 - Disinfection of animals.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has been...

Disinfection Pilot Trial for Little Miami WWTP | Science ...

Science.gov (United States)

There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

UASB reactor effluent disinfection by ozone and chlorine

NARCIS (Netherlands)

Ribeiro da Silvia, G.H.; Bruning, H.; Gerrity, D.; Daniel, L.A.

2015-01-01

This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L-1, followed by chlorine doses of 10, 20 and 30

An Increase in Healthcare-Associated Clostridium difficile Infection Associated with Use of a Defective Peracetic Acid-Based Surface Disinfectant.

Science.gov (United States)

Cadnum, Jennifer L; Jencson, Annette L; O'Donnell, Marguerite C; Flannery, Elizabeth R; Nerandzic, Michelle M; Donskey, Curtis J

2017-03-01

BACKGROUND We investigated an increase in the incidence of healthcare-associated Clostridium difficile infection (CDI) that occurred following a change from a bleach disinfectant to a peracetic acid-based disinfectant. OBJECTIVE To evaluate the efficacy of the peracetic acid-based disinfectant. DESIGN Laboratory-based product evaluation. METHODS The commercial peracetic acid-based product is activated on site by mixing a small volume of concentrated hydrogen peroxide and peracetic acid present in a "SmartCap" reservoir with the remaining contents of the container. We measured concentrations of peracetic acid in newly activated and in-use product and determined the stability of nonactivated and activated product. We tested the efficacy of the product against C. difficile spores using the American Society for Testing and Materials standard quantitative carrier disk test method. RESULTS Measured concentrations of peracetic acid (50-800 parts per million [ppm]) were significantly lower than the level stated on the product label (1,500 ppm), and similar results were obtained for containers from multiple lot numbers and from another hospital. Product with peracetic acid levels below 600 ppm had significantly reduced activity against C. difficile spores. Peracetic acid concentrations were reduced markedly after storage of either activated or nonactivated product for several weeks. The Environmental Protection Agency confirmed the finding of low disinfectant levels and ordered discontinuation of sale of the product. CONCLUSION Use of a defective peracetic acid-based surface disinfectant may have contributed to an increase in healthcare-associated CDI. Our findings highlight the importance of evaluating the efficacy of liquid disinfectants in healthcare settings. Infect Control Hosp Epidemiol 2017;38:300-305.

Waterline ATS B. globigii spore water disinfection data

Data.gov (United States)

U.S. Environmental Protection Agency — Disinfection of B. globigii spores (a non-pathogenic surrogate for B. anthracis) in clean and dirty water using the ATS-Waterline system, which uses ultraviolet...

Life Cycle Environmental Impacts of Disinfection Technologies Used in Small Drinking Water Systems.

Science.gov (United States)

Jones, Christopher H; Shilling, Elizabeth G; Linden, Karl G; Cook, Sherri M

2018-03-06

Small drinking water systems serve a fifth of the U.S. population and rely heavily on disinfection. While chlorine disinfection is common, there is interest in minimizing chemical addition, especially due to carcinogenic disinfection byproducts and chlorine-resistant pathogens, by using ultraviolet technologies; however, the relative, broader environmental impacts of these technologies are not well established, especially in the context of small (environmental trade-offs between chlorine and ultraviolet disinfection via comparative life cycle assessment. The functional unit was the production of 1 m 3 of drinking water to U.S. Treatment included cartridge filtration followed by either chlorine disinfection or ultraviolet disinfection with chlorine residual addition. Environmental performance was evaluated for various chlorine contact zone materials (plastic, concrete, steel), ultraviolet validation factors (1.2 to 4.4), and electricity sources (renewable; U.S. average, high, and low impact grids). Performance was also evaluated when filtration and chlorine residual were not required. From a life cycle assessment perspective, replacing chlorine with UV was preferred only in a limited number of cases (i.e., high pumping pressure but filtration is not required). In all others, chlorine was environmentally preferred, although some contact zone materials and energy sources had an impact on the comparison. Utilities can use these data to inform their disinfection technology selection and operation to minimize environmental and human health impacts.

UV disinfection of water. 1. Effect on microorganisms/virus conditions which can limit the use of UV radiation as a means of disinfection

Energy Technology Data Exchange (ETDEWEB)

Skipperud, E; Johansen,; Myhrstad, J A [Statens Inst. for Folkehelse, Oslo (Norway)

1978-01-01

UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW).

Spatial variations in the occurrence of potentially genotoxic disinfection by-products in drinking water distribution systems in China.

Science.gov (United States)

Li, Chunmei; Wang, Donghong; Xu, Xiong; Xu, Meijia; Wang, Zijian

2017-12-01

We investigated the occurrence of disinfection by-products (DBPs) with genotoxic potential in plant effluent and distribution water samples from four drinking water treatment plants in two Chinese cities using comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry. We tested the samples for 37 DBPs with genotoxic potential, which we had previously identified and prioritized in water under controlled laboratory conditions. Thirty of these DBPs were found in the water samples at detection frequencies of between 10% and 100%, and at concentrations between 3.90 and 1.77 × 10 3  ng/L. Of the DBPs detected, the concentrations of 1,1,1-trichloropropan-2-one were highest, and ranged from 299 to 1.77 × 10 3  ng/L with an average of 796 ng/L. The concentrations of 6-chloro-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine and 2,6-ditert-butylcyclohexa-2,5-diene-1,4-dione were also much higher, and ranged from 107 to 721 ng/L, and from 152 to 504 ng/L, respectively. Concentrations of 1,1,1-trichloropropan-2-one, 2-chloro-1-phenylethanone, 2,2-dichloro-1-phenylethanone and 6-chloro-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine were highest at or near the treatment plants and decreased with increasing distance from the plants. Patterns in the concentrations of benzaldehyde, 2-phenylpropan-2-ol, and 1-methylnaphthalene differed between plants. The levels of DBPs such as 4-ethylbenzaldehyde, (E)-non-2-enal, and 1-phenylethanone were relatively constant within the distribution systems, even at the furthest sampling points (20 km drinking water. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

Directory of Open Access Journals (Sweden)

John Anthony Byrne

2015-03-01

Full Text Available Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems.

Science.gov (United States)

Pehlivanoglu-Mantas, Elif; Hawley, Elisabeth L; Deeb, Rula A; Sedlak, David L

2006-01-01

The probable human carcinogen nitrosodimethylamine (NDMA) is produced when wastewater effluent is disinfected with chlorine. In systems where wastewater effluent is used for landscape or crop irrigation, relatively high chlorine doses (i.e., up to 2,000,mg-min/L) are often used to ensure adequate disinfection and to minimize biofouling in the irrigation system. To assess the formation of NDMA in such systems, samples were collected from several locations in full-scale wastewater treatment systems and their associated irrigation systems. Up to 460 ng/L of NDMA was produced in full-scale systems in which chloramines were formed when wastewater effluent was disinfected with chlorine in the presence of ammonia. Less than 20 ng/L of NDMA was produced in systems that used free chlorine (i.e., HOCl/OCl(-)) for disinfection in the absence of ammonia. The production of NDMA in ammonia-containing systems was correlated with the concentration of NDMA precursors in the wastewater effluent and the overall dose of chlorine applied. Much of the NDMA formation occurred in chlorine contact basins or in storage basins where water that contained chloramines was held after disinfection. When landscape or crop irrigation is practiced with ammonia-containing wastewater effluent, NDMA production can be controlled by use of lower chlorine doses or by application of alternative disinfectants.

Disinfection efficacy of contact lens care solutions against ocular pathogens.

Science.gov (United States)

Miller, M J; Callahan, D E; McGrath, D; Manchester, R; Norton, S E

2001-01-01

Three commercially available products labeled as multi-purpose contact lens solutions, one multi-purpose disinfecting solution, and a hydrogen peroxide system were evaluated for antimicrobial activity according to the current International Organization for Standardization (ISO) and the U.S. Food and Drug Administration (FDA) stand-alone procedure for disinfecting products. One multi-purpose solution was selected to assess its antimicrobial activity against two human corneal isolates of Pseudomonas aeruginosa. Products were challenged with bacteria and fungi, and following a specified period, aliquots of inoculated test solution were neutralized and plated on validated recovery media. After incubation the number of viable microorganisms was enumerated and mean log reductions determined. ReNu MultiPlus (Bausch & Lomb, Rochester, NY), AOSEPT (CIBA Vision Corporation, Duluth, GA), and Opti-Free Express with Aldox (Alcon Laboratories, Ft. Worth, TX) were the only lens care products that met the stand-alone criteria for all required microorganisms within their minimum recommended disinfection time. Of these, ReNu MultiPlus provided the greatest overall antimicrobial activity. ReNu MultiPlus demonstrated a significantly higher mean log reduction of Staphylococcus aureus and Serratia marcescens than Opti-Free Express. ReNu MultiPlus also gave a higher mean log reduction of S. aureus and S. marcescens than AOSEPT, and a higher mean log reduction of Candida albicans and Fusarium solani than AOSEPT, Complete Comfort Plus (Allergan, Irivine, CA), and Solo-Care (CIBA Vision Corp.) (at 4 hours). Both Complete Comfort Plus and Solo-Care (at 4 hours) met the primary acceptance criteria for bacteria; however, neither product possessed enough antimicrobial activity to meet the minimum criteria for yeast or mold. ReNu Multiplus was effective against corneal isolates of P. aeruginosa. ReNu MultiPlus, AOSEPT, and Opti-Free Express met the requirements of the stand-alone primary

Regulation of sporicides under the European Biocidal Products Directive.

Science.gov (United States)

Low, A

2011-03-01

Disinfectants (including sporicides) used in the healthcare setting fall within the scope of the European Biocidal Products Directive (98/8/EC). The active substances used in these products will be evaluated as part of an EU wide review programme, to determine whether they can be used in biocidal products without undue risks to humans, animals and the environment, and that these products will be effective. Following the review of an active substance, biocidal products containing the active substance will become subject to regulatory controls in all EU Member States. This paper discusses how the Directive operates, both through the review programme and the authorisation of biocidal products at the Member State level, together with the requirements to provide data on the efficacy of both the active substances and end-use biocidal products. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

UV DISINFECTION GUIDANCE MANUAL FOR THE ...

Science.gov (United States)

Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

Formation of Emerging Disinfection By-products by Chlorination/Chloramination of Seawater Impacted by Algal Organic Matter

KAUST Repository

Nihemaiti, Maolida; Le Roux, Julien; Croue, Jean-Philippe

2015-01-01

The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

Formation of Emerging Disinfection By-products by Chlorination/Chloramination of Seawater Impacted by Algal Organic Matter

KAUST Repository

Nihemaiti, Maolida

2015-08-31

The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

In situ disinfection of sewage contaminated shallow groundwater: a feasibility study.

Science.gov (United States)

Bailey, Morgan M; Cooper, William J; Grant, Stanley B

2011-11-01

Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4-5 mg L(-1) of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cleaning and disinfection programs against Campylobacter jejuni for broiler chickens: productive performance, microbiological assessment and characterization.

Science.gov (United States)

Castro Burbarelli, Maria Fernanda de; do Valle Polycarpo, Gustavo; Deliberali Lelis, Karoline; Granghelli, Carlos Alexandre; Carão de Pinho, Agatha Cristina; Ribeiro Almeida Queiroz, Sabrina; Fernandes, Andrezza Maria; Moro de Souza, Ricardo Luiz; Gaglianone Moro, Maria Estela; de Andrade Bordin, Roberto; de Albuquerque, Ricardo

2017-09-01

Detailed cleaning and disinfection programs aims to reduce infection pressure from microorganisms from one flock to the next. However, studies evaluating the benefits to poultry performance, the sanitary status of the facilities, and the sanitary quality of the meat are rarely found. Thus, this study was designed to evaluate 2 cleaning and disinfecting programs regarding their influence on productive performance, elimination of Campylobacter, and characterization of Campylobacter jejuni strains when applied to broiler chickens' facilities. Two subsequent flocks with 960 birds each were distributed into 32 pens containing 30 birds each. In the first, the whole flock was inoculated with a known strain of Campylobacter jejuni in order to contaminate the environment. In the second flock, performance and microbiological evaluations were done, characterizing an observational study between 2 cleaning and disinfection programs, regular and proposed. The regular program consisted of sweeping facilities, washing equipment and environment with water and neutral detergent. The proposed cleaning program consisted of dry and wet cleaning, application of 2 detergents (one acid and one basic) and 2 disinfectants (250 g/L glutaraldehyde and 185 g/L formaldehyde at 0.5% and 210 g/L para-chloro-meta-cresol at 4%). Total microorganism count in the environment and Campylobacter spp. identification were done for the microbiological assessment of the environment and carcasses. The positive samples were submitted to molecular identification of Campylobacter spp. and posterior genetic sequencing of the species identified as Campylobacter jejuni. The birds housed in the facilities and submitted to the proposed treatment had better performance when compared to the ones in the regular treatment, most likely because there was a smaller total microorganism count on the floor, walls, feeders and drinkers. The proposed program also resulted in a reduction of Campylobacter spp. on floors

Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

International Nuclear Information System (INIS)

Wang, Xin; Wang, Juan; Zhang, Yahe; Shi, Quan; Zhang, Haifeng; Zhang, Yu; Yang, Min

2016-01-01

Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI mod ), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Wang, Xin; Wang, Juan [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Yahe; Shi, Quan [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhang, Haifeng; Zhang, Yu [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Min, E-mail: yangmin@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

2016-06-01

Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI{sub mod}), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

Non-PRASA Drinking Water Research on UV Disinfection in Puerto Rico

Science.gov (United States)

The U.S. EPA and InterAmerican University of San German worked with water treatment operators from Patillas, Puerto Rico on the installation, training and testing of pretreatment/UV disinfection systems in the communities of La Sofia and Apeadero. This presentation provides path...

Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

International Nuclear Information System (INIS)

Kweon, Dae Cheol; Park, Peom

2001-01-01

A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 μW · s/cm 2 Win in 30 second relative to ultraviolet dose in time

Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2

Science.gov (United States)

Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

Directory of Open Access Journals (Sweden)

Engelhart, Steffen

2015-12-01

Full Text Available This in vitro study investigated the external disinfection of two needle-free connection devices (NFC using Octeniderm (spraying and wiping technique vs. Descoderm pads (wiping technique. The split-septum membrane of the NFC was contaminated with >10 CFU . The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in solution was highly effective (CFU reduction ≥4 log against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with . Our investigation underlines that (i in clinical practice disinfection of NFCs before use is mandatory, and that (ii details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity.

Modelling of Disinfection by-products formation via UV irradiation of the water from Tajan River (source water for Sari drinking water, Iran

Directory of Open Access Journals (Sweden)

Allahbakhsh Javid

2013-11-01

Full Text Available Background & Aims of the Study Irradiation with ultraviolet light (UV is used for the disinfection of bacterial contaminants in the production of potable water. The main objective of the study was to investigate and model Disinfection By-Products (DBPs formation due to the UV Irradiation of the Tajan River water under different Irradiation conditions. Materials & Methods:  Water samples were collected throughout September 2011 to August 2013. Transportation of the sample to the laboratory was done on ice in a cooler, and physiochemical analysis was conducted immediately within one day. Dissolved organic carbon (DOC was determined by a TOC analyzer. Irradiation experiments were conducted in a series of 25 mL glass serum bottles with Teflon septa. The present study adopts an orthogonal design. The design involved irradiation with UV at a UV/DOC ratio of 0.5–3.0 and incubating (headspace-free storage for 5–25 sec. A 1 mM phosphate buffer maintained the pH at 6, 7, or 8 respectively, and an incubator maintained the temperature (Temp at 15, 20, or 25 °C respectively. The development of empirical models for DBPs formation used a multivariate regression procedure (stepwise which applied the SPSS System for Windows (Version 16.0. Results:  The results showed that the total DBPs formation ranged between 12.3 and 67.4 mg/l and that control of the levels was primarily due to the reaction time and the dissolved organic carbon level (DOC in the water. Conclusions:  Reaction time and level of DOC concentrations in water exerted a dominant influence on the formation of DBPs during the UV irradiation of water from the Tajan River. The relationships between the measured and predicted values were satisfactory with R 2 values ranging from 0.89 (for Octanal–0.92 (for Formaldehydes. The DOC level in water is the key factor in controlling DBPs formation.

Fine Sprays for Disinfection within Healthcare

Directory of Open Access Journals (Sweden)

G Nasr

2016-09-01

Full Text Available Problems exist worldwide with Hospital Acquired Infections (HAI's. The Spray Research Group (SRG have been working with relevant industries in developing a product which can provide a delivery system for treatment chemicals for surfaces, including the design and testing of a novel Spill-Return Atomiser (SRA for this purpose. A comprehensive description of this atomiser has already been given. This paper reports on a new application of this atomiser and discusses the problem of spray coating for disinfection that has been considered very little in previous work. The related spray coating performance tests in developing the product are thus provided. The experimental work includes determining the required spray duration and the coverage area produced by different sprays, including the analysis of the effects of atomiser positions, configurations, and the required number of atomisers. Comparison is made with the efficacy of an ultrasonic gas atomiser that is currently used for this purpose. The investigation has found that the utilisation of fine sprays (10μm>D32>25μm at high liquid pressure (<12MPa and low flow rates (<0.3 l/min is suitable for surface disinfection in healthcare applications (i.e. MRSA, VRSA etc.

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

OpenAIRE

Denise de Andrade; Emília L. S. Angerami; Carlos Roberto Padovani

2000-01-01

In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were se...

Effect of Different Disinfection Protocols on Microbial and Biofilm Contamination of Dental Unit Waterlines in Community Dental Practices

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Laura Dallolio

2014-02-01

Full Text Available Output water from dental unit waterlines (DUWLs may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02% and stabilized chlorine dioxide (0.22%, respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.

Science.gov (United States)

Dallolio, Laura; Scuderi, Amalia; Rini, Maria S; Valente, Sabrina; Farruggia, Patrizia; Sabattini, Maria A Bucci; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

2014-02-18

Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

Selective Photocatalytic Disinfection by Coupling StrepMiniSog to the Antibody Catalyzed Water Oxidation Pathway.

Science.gov (United States)

Wurtzler, Elizabeth M; Wendell, David

2016-01-01

For several decades reactive oxygen species have been applied to water quality engineering and efficient disinfection strategies; however, these methods are limited by disinfection byproduct and catalyst-derived toxicity concerns which could be improved by selectively targeting contaminants of interest. Here we present a targeted photocatalytic system based on the fusion protein StrepMiniSOG that uses light within the visible spectrum to produce reactive oxygen species at a greater efficiency than current photosensitizers, allowing for shorter irradiation times from a fully biodegradable photocatalyst. The StrepMiniSOG photodisinfection system is unable to cross cell membranes and like other consumed proteins, can be degraded by endogenous digestive enzymes in the human gut, thereby reducing the consumption risks typically associated with other disinfection agents. We demonstrate specific, multi-log removal of Listeria monocytogenes from a mixed population of bacteria, establishing the StrepMiniSOG disinfection system as a valuable tool for targeted pathogen removal, while maintaining existing microbial biodiversity.

Selective Photocatalytic Disinfection by Coupling StrepMiniSog to the Antibody Catalyzed Water Oxidation Pathway.

Directory of Open Access Journals (Sweden)

Elizabeth M Wurtzler

Full Text Available For several decades reactive oxygen species have been applied to water quality engineering and efficient disinfection strategies; however, these methods are limited by disinfection byproduct and catalyst-derived toxicity concerns which could be improved by selectively targeting contaminants of interest. Here we present a targeted photocatalytic system based on the fusion protein StrepMiniSOG that uses light within the visible spectrum to produce reactive oxygen species at a greater efficiency than current photosensitizers, allowing for shorter irradiation times from a fully biodegradable photocatalyst. The StrepMiniSOG photodisinfection system is unable to cross cell membranes and like other consumed proteins, can be degraded by endogenous digestive enzymes in the human gut, thereby reducing the consumption risks typically associated with other disinfection agents. We demonstrate specific, multi-log removal of Listeria monocytogenes from a mixed population of bacteria, establishing the StrepMiniSOG disinfection system as a valuable tool for targeted pathogen removal, while maintaining existing microbial biodiversity.

Regulation of adrenomedullin and nitric oxide production by periodontal bacteria.

Science.gov (United States)

Hussain, Q A; McKay, I J; Gonzales-Marin, C; Allaker, R P

2015-10-01

In periodontitis the host response to bacterial challenge includes activity of the multifunctional molecules adrenomedullin (AM) and nitric oxide (NO). The aim of this study was to investigate the role of periodontal bacteria in regulating the production of these molecules from cultured cells. Regulation of AM and NO production from oral keratinocytes when challenged with culture supernatants from Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Veillonella atypica, Streptococcus salivarius and Candida albicans was examined. AM and NO were measured in cell culture supernatants using an enzyme-linked immunosorbent assay and the nitrate/nitrite (NO metabolites) Griess assay respectively. Cellular production of AM and inducible NO synthase was also analysed in target cells by immunofluorescence and Western blot analysis. The inter-relationship of AM and NO production were further investigated with macrophages. A. actinomycetemcomitans and C. rectus induced maximal levels of both AM and NO after 6 and 48 h respectively from oral keratinocytes. AM production in macrophages was upregulated in response to the NO donor S-nitrosoglutathione and partially blocked by the inducible NO synthase inhibitor, N(ω) -Nitro-l-arginine methyl ester hydrochloride. Likewise, NO production was increased upon exposure to AM, while the AM receptor antagonist AM 22-52 reduced the release of NO. Pathogens associated with aggressive periodontitis, A. actinomycetemcomitans and C. rectus, were more effective than those associated with chronic periodontitis, P. gingivalis and Prev. intermedia, and commensals, S. salivarius and V. atypica, as regards the upregulation of AM and NO production from oral keratinocytes. Interaction between these molecules was also demonstrated with macrophages. Understanding the coordinated regulation of AM and NO production in response to periodontal bacteria may identify

Evaluation of the hygienogram scores and related data obtained after cleaning and disinfection of poultry houses in Flanders during the period 2007 to 2014.

Science.gov (United States)

Maertens, H; De Reu, K; Van Weyenberg, S; Van Coillie, E; Meyer, E; Van Meirhaeghe, H; Van Immerseel, F; Vandenbroucke, V; Vanrobaeys, M; Dewulf, J

2018-02-01

Cleaning and disinfection (C&D) of poultry houses is an essential aspect in farm hygiene management. Adequate performance of the different steps of a C&D protocol and the use of suitable products are key to prevent and control zoonoses and animal diseases. Hygiene monitoring on total aerobic flora through sampling with agar contact plates at different locations of the poultry house results in a hygienogram score that is used to evaluate the proper execution of C&D.This study analyzed the hygienogram scores of 19,739 poultry flocks in Flanders after C&D. Data relating to the C&D protocol, i.e., year, season, husbandry system, production type, cleaning product, sampler, active components of the disinfectant, disinfection time, disinfection temperature, and disinfection responsible, were collected.The average hygienogram score decreased significantly over time, suggesting a general improvement between 2007 and 2014. Differences in scores were found among the husbandry systems, with the barn/aviary system having a significantly better hygienogram score compared to the floor house, furnished cage, and battery. Significantly better scores also were found when a cleaning product was used in the C&D protocol. Disinfection with a peracetic acid and hydrogen peroxide combination or formaldehyde gave the best scores. In addition, C&D protocols using ≥2 different disinfectants showed improved results compared to the use of one single disinfectant. Finally, disinfection applied by a specialist contractor resulted in a better score compared to disinfection by the farmer.In conclusion, analysis of the hygienogram scores and related data allowed identifying several factors, resulting in an improvement, which may reduce the total bacterial load in poultry stables and, consequently, the number of zoonotic and pathogenic micro-organisms. © 2017 Poultry Science Association Inc.

7 CFR 205.603 - Synthetic substances allowed for use in organic livestock production.

Science.gov (United States)

2010-01-01

... livestock production. 205.603 Section 205.603 Agriculture Regulations of the Department of Agriculture... organic livestock production. In accordance with restrictions specified in this section the following synthetic substances may be used in organic livestock production: (a) As disinfectants, sanitizer, and...

Moist Heat Disinfection and Revisiting the A0 Concept.

Science.gov (United States)

McCormick, Patrick J; Schoene, Michael J; Dehmler, Matthew A; McDonnell, Gerald

2016-04-02

Moist heat is employed in the medical device, pharmaceutical, and food processing industries to render products and goods safe for use and human consumption. Applications include its use to pasteurize a broad range of foods and beverages, the control of microbial contamination of blood products, and treatment of bone tissue transplants and vaccines. In the pharmaceutical industry, water heated to 65°C to 80°C is used to sanitize high-purity water systems. In healthcare, it has been employed for decades to disinfect patient care items ranging from bedpans to anesthesia equipment. There is a good understanding of the conditions necessary to achieve disinfection of microorganisms at temperatures ranging from 65°C to 100°C. Based on this information, the efficacy of moist heat processes at a range of exposure times and temperatures can be quantified based on mathematical models such as the A0 calculation. While the A0 concept is recognized within the European healthcare community, it has yet to be widely adopted within the United States. This article provides information regarding the A0 concept, a brief overview of the classification of thermal disinfection for use with healthcare applications within the United States, and recent data on reinvestigating the thermal disinfection of a selected panel of microorganisms and a mixed culture biofilm.

Regulation of natural health products in Canada.

Science.gov (United States)

Smith, Alysyn; Jogalekar, Sumedha; Gibson, Adam

2014-12-02

In Canada, all natural health products (NHPs) are regulated by Health Canada (HC) under the Food and Drugs Act and the Natural Health Product Regulations. All authorized products undergo pre-market assessment for safety, efficacy and quality and the degree of pre-market oversight varies depending on the risk of the product. In Canada, over 70,000 products have been authorized for sale and over 2000 sites have been licensed to produce NHPs. In the management of NHPs on the Canadian market, HC employs a number of active and collaborative methods to address the most common issues such as contamination, adulteration and deceptive or misleading advertising practices. HC is currently evolving its approaches to NHPs to recognize them as part of the larger group of health products available without a prescription. As such, the regulatory responsibility for all over-the-counter (OTC) drugs, including non-prescription drugs and NHPs, has been transferred to a single federal division. As a result of this transition a number of benefits are being realized with respect to government efficiency, clarity for industry, support for new innovations and consolidated government interactions with the Canadian market. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Inhibition of trihalomethane formation in city water by radiation-ozone treatment and rapid composting of radiation disinfected sewage sludge

International Nuclear Information System (INIS)

Takehisa, M.; Arai, H.; Arai, M.

1985-01-01

Humic acid and Fulvic acid in natural water are precursors of carcinogenic THM which is formed during chlorine disinfection in city water processing. The radiation-oxidation process in the presence of ozone is effective to remove the precursors. The THM formation was reduced more than the decrease in TOC by the combination treatment. This is mainly due to a change in the chemical structure of the oxidation products. A composting of radiation disinfected sludge cake for agricultural reuse could be achieved within 3 days primary fermentation in a sewage plant. The rapid fermentation with use of radiation is effective to scale down of a fermentor of composting plant and the process reduces a health risk from the workers as well as final users. (author)

Inhibition of trihalomethane formation in city water by radiation-ozone treatment and rapid composting of radiation disinfected sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Takehisa, M; Arai, H; Arai, M

1985-01-01

Humic acid and Fulvic acid in natural water are precursors of carcinogenic THM which is formed during chlorine disinfection in city water processing. The radiation-oxidation process in the presence of ozone is effective to remove the precursors. The THM formation was reduced more than the decrease in TOC by the combination treatment. This is mainly due to a change in the chemical structure of the oxidation products. A composting of radiation disinfected sludge cake for agricultural reuse could be achieved within 3 days primary fermentation in a sewage plant. The rapid fermentation with use of radiation is effective to scale down a fermentor of a composting plant and the process reduces health risk for the workers as well as final users.

Comparative study with two different enrichments in the culture media used in the disinfectant efficacy assay.

Science.gov (United States)

Sabagh, Bruna Peres; Souto, Aline da Silva Soares; Reis, Louise Moreira; Silva, Sérgio Alves da; Pereira, Daniella Cristina Rodrigues; Neves, Marta de Campos; Pinheiro, Rodrigo Rollin; Duarte, Rafael Silva; Miyazaki, Neide Hiromi Tokumaru; Bôas, Maria Helena Simões Villas

2012-02-01

Recent changes in Brazilian legislation for commercial disinfectants have been published due to the recent epidemic of nosocomial infections caused by rapidly growing mycobacteria (RGM) in many states of Brazil over the last 8years. One of these documents requires that all the manufacturers provide evidence of efficacy of sterilizing and disinfectant products, used for semi critical medical devices, against the Mycobacterium bovis BCG Moreau and Mycobacterium abscessus subsp. bolletii INCQS 00594 strains by using the Confirmative in vitro Test for Determining Tuberculocidal Activity of Disinfectants recommended by the Association of Official Analytical Chemists. These changes have caused additional costs and increased problems for importation of enrichment products at national laboratories where disinfectant efficacy assay service is performed. Middlebrook ADC Enrichment (ADC) is provided by a unique manufacturer and used in the official protocol. The aim of the present study was to evaluate an alternative in house low-cost enrichment composed of fetal bovine serum and glucose (FBSG) with ADC for performance of disinfectant efficacy assay against mycobacteria. After obtaining the growth curves for M. abscessus ATCC 19977, M. abscessus subsp. bolletii INCQS 00594, Mycobacterium chelonae ATCC 35752, and Mycobacterium fortuitum ATCC 6841 by using ADC enrichment and FBSG in Kirchners and 7H9 culture media. Through statistical analysis via the Kruskal-Wallis test on the evaluation of microorganism growth rate, it was observed that there was no inhibition of RGM growth by any of the enrichments used. These results suggest that low-cost enrichment FBSG may be used as a potential substitute of ADC for composition of media for mycobacterial growth, including in disinfectant tests. Copyright © 2011 Elsevier B.V. All rights reserved.

Assessment of air and water contamination by disinfection by-products at 41 indoor swimming pools.

Science.gov (United States)

Tardif, Robert; Catto, Cyril; Haddad, Sami; Simard, Sabrina; Rodriguez, Manuel

2016-07-01

This study was aimed at assessing the profiles (occurrence and speciation) of disinfection by-product (DBP) contamination in air and water of a group of 41 public indoor swimming pools in Québec (Canada). The contaminants measured in the water included the traditional DBPs [i.e., four trihalomethanes (THMs), six haloacetic acids (HAAs)] but also several emergent DBPs [i.e., halonitriles, halonitromethanes, haloketones and nitrosodimethylamine (NDMA)]. Those measured in the air comprised THMs and chloramines (CAMs). Overall, extremely variable DBP levels were found from one pool to another (both quantitatively and in terms of speciation). For instance, in water, among the four THMs, chloroform was usually the most abundant compound (37.9±25.7µg/L). Nevertheless, the sum of the three other brominated THMs represented more than 25% of total THMs at almost half the facilities visited (19 cases). In 13 of them, the levels of brominated THMs (66±24.2µg/L) even greatly outweighed the levels of chloroform (15.2±6.31µg/L). Much higher levels of HAAs (294.8±157.6µg/L) were observed, with a consistent preponderance of brominated HAAs in the swimming pools with more brominated THMs. NDMA levels which were measured in a subset of 8 pools ranged between 2.8ng/L and 105ng/L. With respect to air, chloroform was still the most abundant THM globally (119.4±74.2µg/m(3)) but significant levels of brominated THMs were also observed in various cases, particularly in the previously evoked group of 13 swimming pools with preponderant levels of brominated THMs in water. CAM levels (0.23±0.15mg/m(3)) varied highly, ranging from not detected to 0.56mg/m(3). Overall, the levels were generally relatively high compared to current guidelines or reference values from several countries, and they point to a relatively atypical presence of brominated compounds, and to significant levels of emergent DBPs for which health risk is less documented. Copyright © 2016 Elsevier Inc. All rights

Applications of Photocatalytic Disinfection

Directory of Open Access Journals (Sweden)

Joanne Gamage

2010-01-01

Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

Energy Technology Data Exchange (ETDEWEB)

Kweon, Dae Cheol; Park, Peom [Ajou Univ., Suwon (Korea, Republic of)

2001-12-15

A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 {mu}W {center_dot} s/cm{sup 2}Win in 30 second relative to ultraviolet dose in time.

Predictors of stethoscope disinfection among pediatric health care providers.

Science.gov (United States)

Muniz, Jeanette; Sethi, Rosh K V; Zaghi, Justin; Ziniel, Sonja I; Sandora, Thomas J

2012-12-01

Stethoscopes are contaminated with bacteria, but predictors of stethoscope disinfection frequency are unknown. We sought to describe health care provider stethoscope disinfection attitudes and practices and determine predictors of frequent disinfection. We used an anonymous online survey of nurses, nurse practitioners, and physicians at a pediatric hospital. We assessed frequency and methods of disinfection, perceptions of contamination, and barriers to disinfection. Multivariate logistic regression models were used to identify independent predictors of disinfecting after every use. One thousand four hundred one respondents completed the survey: 76% believed that infection transmission occurs via stethoscopes, but only 24% reported disinfecting after every use. In multivariate analyses, belief that infection transmission occurs via stethoscopes significantly increased the odds of disinfection after every use (odds ratio [OR], 2.06 [95% confidence interval (CI): 1.38-3.06]). The odds of disinfection after every use were significantly decreased in those who perceived the following barriers: lack of time (OR, 0.31 [95% CI: 0.18-0.54]), lack of access to disinfection material (OR, 0.41 [95% CI: 0.29-0.57]), or lack of visual reminders to disinfect (OR, 0.22 [95% CI: 0.14-0.34]). Only a minority of pediatric health care providers reported disinfecting their stethoscopes after every use. Increasing access to disinfection materials and visual reminders in health care facilities may improve stethoscope disinfection practices. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

9 CFR 83.7 - Shipping containers; cleaning and disinfection.

Science.gov (United States)

2010-01-01

... HEMORRHAGIC SEPTICEMIA § 83.7 Shipping containers; cleaning and disinfection. (a) All live fish that are to be... been cleaned and disinfected. (1) Cleaning and disinfection of shipping containers must be monitored by... who issues the ICI. (2) Cleaning and disinfection must be sufficient to neutralize any VHS virus to...

Disinfection ultraviolet radiation bulk food products

OpenAIRE

Семенов, А. А.

2014-01-01

В работе представлены результаты обеззараживания сыпучих пищевых продуктов ультрафиолетовым излучением. Предложена технология бактерицидного обеззараживания сыпучих продуктов с размером частиц до 50 мкм. Проведены необходимые расчеты, связанные с дозой облучения, с временем пребывания частиц в зоне облучения и необходимой дозой инактивации в зависимости от вида бактерий. Considered the results of bulk food products disinfection by ultraviolet radiation. The technology bactericidal disinfec...

Sludge disinfection by combined treatment of bleaching powder and irradiation

International Nuclear Information System (INIS)

Harsoyo

1987-01-01

Sludge disinfection by combined treatment of bleaching powder and irradiation. Disinfection of sludge by combined treatment of bleaching powder and irradiation has been investigated. Sludge were obtained from water and waste sanitation department (Dinas Kebersihan) DKI located at Kebon Nanas, Jakarta. Sludge were mixed with bleaching powder at the concentration of 0, 10 and 20 mg/l and then irradiated in multipurpose panoramic batch irradiator (PANBIT) with doses of 2, 4, 6, 8, and 10 kGy and a dose rate 9 kGy/h. The reducing colony form unit caused by the combined treatment depend on type bacteria observed in sludge. Pathogenic bacteria as Clostridium still survive at a dose of 10 kGy on sludge containing 20 mg/l bleaching powder, but Salmonella, Shigella, and Vibrio were not detected in this experiment, neither in the control nor in the irradiated samples. (author). 14 refs.; 4 figs

Disinfection in Wastewater Treatment Plants: Evaluation of Effectiveness and Acute Toxicity Effects

Directory of Open Access Journals (Sweden)

Maria Cristina Collivignarelli

2017-09-01

Full Text Available In Italy, urban wastewater disinfection is regulated in the third part of Legislative Decree n. 152/2006, which states that wastewater treatment plants (WWTPs must include a disinfection unit, with a capacity exceeding 2000 Population Equivalent (PE. This treatment shall ensure microbial quality and health security. The legislation provides the following limits for wastewater: Escherichia coli (E. coli concentration below 5000 CFU 100 mL−1 (recommended value, active chlorine concentration below 0.2 mg L−1 and lack of acute toxicity. The compliance with these conditions is shown by means of the study of correct disinfectant dosage, which also depends on wastewater characteristics. An investigation at the regional level (from 2013 to 2016 shows a correlation between acute toxicity discharge and disinfection treatment through chemical reagents (mainly with the use of chlorine compounds and peracetic acid. The experimental work concerns two active sludge WWTPs in northern Italy with small capacity (10,000–12,000 PE. The activities provide the assessment of microbiological quality and toxicity of WWTPs effluents in relation to the dosage of sodium hypochlorite and peracetic acid, by means of the use of batch tests. The results show that with similar disinfectant dosage and comparable initial E. coli concentration, peracetic acid exhibits the best performance in terms of microbial removal (with removal yields up to 99.99%. Moreover, the acute toxicity was evident at higher doses and therefore with higher residuals of peracetic acid (2.68 mg L−1 compared to the free residual chlorine (0.17 mg L−1.

40 CFR 141.172 - Disinfection profiling and benchmarking.

Science.gov (United States)

2010-07-01

... benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving 10,000 or More People § 141.172 Disinfection profiling and benchmarking. (a... sanitary surveys conducted by the State. (c) Disinfection benchmarking. (1) Any system required to develop...

Comparison of the disinfection efficacy of chlorine-based products for inactivation of viral indicators and pathogenic bacteria in produce wash water.

Science.gov (United States)

Chaidez, Cristobal; Moreno, Maria; Rubio, Werner; Angulo, Miguel; Valdez, Benigno

2003-09-01

Outbreaks of pathogenic bacteria infections associated with the consumption of fresh produce has occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of three commonly used disinfectants in packing-houses of Culiacan, Mexico (sodium hypochlorite [NaOCl], trichlor-s-triazinetrione [TST] and thrichlormelamine [TCM]) for inactivation of viral indicators and pathogenic bacteria inoculated onto produce wash water. Each microbial challenge consisted of 2 L of water containing approximately 8 log10 bacterial CFU ml(-1), and 8 log10 viral PFU ml(-1) treated with 100 and 300 mg l(-1) of total chlorine with modified turbidity. Water samples were taken after 2 min of contact with chlorine-based products and assayed for the particular microorganisms. TST and NaOCl were found to effectively reduce for bacterial pathogens and viral indicators 8 log10 and 7 log10, respectively (alpha=0.05). The highest inactivation rate was observed when the turbidity was low and the disinfectant was applied at 300 mg l(-1). TCM did not show effective results when compared with the TST and NaOCl (Pturbidity created by the organic and inorganic material present in the water tanks carried by the fresh produce may affect the efficacy of the chlorine-based products.

Biofilms and Oxidizing Biocides; Evaluation of Disinfection and Removal Effects by Using Established Microbial Systems.

Science.gov (United States)

Tachikawa, Mariko

2017-01-01

The formation of bacterial biofilms and their disinfection and removal have been important subjects in the maintenance of water quality in areas such as public spas, swimming pools, food processing lines, industrial water systems, and in the hygienic control of medical devices, hospital procedures, etc. Presented here is an outline of biofilm formation, as well as studies on the disinfection and removal of biofilms by oxidizing biocides using established biofilms. These studies using established biofilms may increase the understanding of the variable response of biofilms to planktonic bacteria, and the unique aspects of oxidizing biocides in the disinfection and removal of biofilms.

Effect of selection of pH in swimming pool on formation of chlorination by-products

DEFF Research Database (Denmark)

Hansen, Kamilla Marie Speht; Willach, Sarah; Mosbæk, Hans

2011-01-01

Chlorine is used as disinfection agent in public swimming pools, but also reacts with organic matter in the water forming chlorinat ed disinfection by-products. In order to evaluate the effect of choice of pHsetpoint in the pool we investigated the effect of chlorination of artificial body fluid...

Discharges of produced waters from oil and gas extraction via wastewater treatment plants are sources of disinfection by-products to receiving streams

Science.gov (United States)

Hladik, Michelle; Focazio, Michael J.; Engle, Mark

2014-01-01

Fluids co-produced with oil and gas production (produced waters) are often brines that contain elevated concentrations of bromide. Bromide is an important precursor of several toxic disinfection by-products (DBPs) and the treatment of produced water may lead to more brominated DBPs. To determine if wastewater treatment plants that accept produced waters discharge greater amounts of brominated DBPs, water samples were collected in Pennsylvania from four sites along a large river including an upstream site, a site below a publicly owned wastewater treatment plant (POTW) outfall (does not accept produced water), a site below an oil and gas commercial wastewater treatment plant (CWT) outfall, and downstream of the POTW and CWT. Of 29 DBPs analyzed, the site at the POTW outfall had the highest number detected (six) ranging in concentration from 0.01 to 0.09 μg L− 1 with a similar mixture of DBPs that have been detected at POTW outfalls elsewhere in the United States. The DBP profile at the CWT outfall was much different, although only two DBPs, dibromochloronitromethane (DBCNM) and chloroform, were detected, DBCNM was found at relatively high concentrations (up to 8.5 μg L− 1). The water at the CWT outfall also had a mixture of inorganic and organic precursors including elevated concentrations of bromide (75 mg L− 1) and other organic DBP precursors (phenol at 15 μg L− 1). To corroborate these DBP results, samples were collected in Pennsylvania from additional POTW and CWT outfalls that accept produced waters. The additional CWT also had high concentrations of DBCNM (3.1 μg L− 1) while the POTWs that accept produced waters had elevated numbers (up to 15) and concentrations of DBPs, especially brominated and iodinated THMs (up to 12 μg L− 1 total THM concentration). Therefore, produced water brines that have been disinfected are potential sources of DBPs along with DBP precursors to streams wherever these wastewaters are discharged.

Nano-TiO2-based photocatalytic disinfection of environmental surfaces contaminated by meticillin-resistant Staphylococcus aureus.

Science.gov (United States)

Petti, S; Messano, G A

2016-05-01

Traditional cleaning and disinfection methods are inefficient for complete decontamination of hospital surfaces from meticillin-resistant Staphylococcus aureus (MRSA). Additional methods, such as nano-TiO2-based photocatalytic disinfection (PCD), could be helpful. To evaluate anti-MRSA activity of PCD on polyvinyl chloride (PVC) surfaces in natural-like conditions. Two identical PVC surfaces were used, and nano-TiO2 was incorporated into one of them. The surfaces were contaminated with MRSA isolated from hospitalized patients using a mist sprayer to simulate the mode of environmental contamination caused by a carrier. MRSA cell density was assessed before contamination until 180min after contamination using Rodac plates. The differences between test and control surfaces in terms of MRSA density and log MRSA density reduction were assessed using parametric and non-parametric statistical tests. Five strains were tested, and each strain was tested five times. The highest median MRSA densities [46.3 and 43.1 colony-forming units (cfu)/cm(2) for control and test surfaces, respectively] were detected 45min after contamination. Median MRSA densities 180min after contamination were 10.1 and 0.7cfu/cm(2) for control and test surfaces, respectively (Pdisinfectant activity remained stable throughout the 25 testing occasions, despite between-test cleaning and disinfection. The anti-MRSA activity of PCD was compatible with the benchmark for surface hygiene in hospitals (surfaces. However, for clinical surfaces, PCD should be regarded as supplemental to conventional decontamination procedures, rather than an alternative. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Bistability in self-activating genes regulated by non-coding RNAs

International Nuclear Information System (INIS)

Miro-Bueno, Jesus

2015-01-01

Non-coding RNA molecules are able to regulate gene expression and play an essential role in cells. On the other hand, bistability is an important behaviour of genetic networks. Here, we propose and study an ODE model in order to show how non-coding RNA can produce bistability in a simple way. The model comprises a single gene with positive feedback that is repressed by non-coding RNA molecules. We show how the values of all the reaction rates involved in the model are able to control the transitions between the high and low states. This new model can be interesting to clarify the role of non-coding RNA molecules in genetic networks. As well, these results can be interesting in synthetic biology for developing new genetic memories and biomolecular devices based on non-coding RNAs

Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

Energy Technology Data Exchange (ETDEWEB)

Postigo, Cristina [Institute for Environmental Assessment and Water Research (IDAEA)—Spanish National Research Council (CID-CSIC), Barcelona (Spain); Richardson, Susan D., E-mail: richardson.susan@sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC (United States)

2014-08-30

Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H{sub 2}O{sub 2}. • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment.

Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

International Nuclear Information System (INIS)

Postigo, Cristina; Richardson, Susan D.

2014-01-01

Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H 2 O 2 . • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment

Treatment of Arctic wastewater by chemical coagulation, UV and peracetic acid disinfection.

Science.gov (United States)

Chhetri, Ravi Kumar; Klupsch, Ewa; Andersen, Henrik Rasmus; Jensen, Pernille Erland

2017-02-16

Conventional wastewater treatment is challenging in the Arctic region due to the cold climate and scattered population. Thus, no wastewater treatment plant exists in Greenland, and raw wastewater is discharged directly to nearby waterbodies without treatment. We investigated the efficiency of physicochemical wastewater treatment, in Kangerlussuaq, Greenland. Raw wastewater from Kangerlussuaq was treated by chemical coagulation and UV disinfection. By applying 7.5 mg Al/L polyaluminium chloride (PAX XL100), 73% of turbidity and 28% phosphate was removed from raw wastewater. E. coli and Enterococcus were removed by 4 and 2.5 log, respectively, when UV irradiation of 0.70 kWh/m 3 was applied to coagulated wastewater. Furthermore, coagulated raw wastewater in Denmark, which has a chemical quality similar to Greenlandic wastewater, was disinfected by peracetic acid or UV irradiation. Removal of heterotrophic bacteria by applying 6 and 12 mg/L peracetic acid was 2.8 and 3.1 log, respectively. Similarly, removal of heterotrophic bacteria by applying 0.21 and 2.10 kWh/m 3 for UV irradiation was 2.1 and greater than 4 log, respectively. Physicochemical treatment of raw wastewater followed by UV irradiation and/or peracetic acid disinfection showed the potential for treatment of arctic wastewater.

Evaluating a new paradigm for comparing surface disinfection in clinical practice.

Science.gov (United States)

Carling, Philip C; Perkins, Jennifer; Ferguson, JoAnn; Thomasser, Anita

2014-11-01

Despite an increasing understanding of the importance of near-patient surfaces in the transmission of healthcare-associated pathogens, there remains a need to define the relative clinical effectiveness of disinfection interventions. A serial 2-phase evaluation of the clinical effectiveness of 2 surface disinfectants. A general acute care hospital. A unique system for quantifying bioburden reduction while monitoring the possible impact of differences in cleaning thoroughness was used to compare the clinical effectiveness of a traditional quaternary ammonium compound (QAC) and a novel peracetic acid/hydrogen peroxide disinfectant (ND) as part of terminal room cleaning. As a result of QAC cleaning, 93 (40%) of 237 cleaned surfaces confirmed by fluorescent marker (DAZO) removal were found to have complete removal of aerobic bioburden. During the ND phase of the study, bioburden was removed from 211 (77%) of 274 cleaned surfaces. Because there was no difference in the thoroughness of cleaning with either disinfectant (65.3% and 66.4%), the significant ([Formula: see text]) difference in bioburden reduction can be attributed to better cleaning efficacy with the ND. In the context of the study design, the ND was 1.93 times more effective in removing bacterial burden than the QAC ([Formula: see text]). Furthermore, the study design represents a new research paradigm in which 2 interventions can be compared by concomitantly and objectively analyzing both the product and process variables in a manner that can be used to define the relative effectiveness of all disinfection cleaning interventions.

Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment.

Science.gov (United States)

Postigo, Cristina; Richardson, Susan D

2014-08-30

Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

Safe drinking water act: Amendments, regulations and standards

International Nuclear Information System (INIS)

Calabrese, E.J.; Gilbert, C.E.; Pastides, H.

1989-01-01

This book approaches the topic of safe drinking water by communicating how the EPA has responded to the mandates of Congress. Chapter 1 summarizes what is and will be involved in achieving safe drinking water. Chapter 2 describes the historical development of drinking water regulations. Chapter 3 summarizes the directives of the Safe Drinking Water Act Amendments of 1986. Chapters 4 through 9 discuss each phase of the regulatory program in turn. Specific problems associated with volatile organic chemicals, synthetic organics, inorganic chemicals, and microbiological contaminants are assessed in Chapter 4 and 5. The unique characteristics of radionuclides and their regulation are treated in Chapter 6. The disinfection process and its resultant disinfection by-products are presented in Chapter 7. The contaminant selection process and the additional contaminants to be regulated by 1989 and 1991 and in future years are discussed in Chapters 8 and 9. EPA's Office of Drinking Water's Health Advisory Program is explained in Chapter 10. The record of public water system compliance with the primary drinking water regulations is detailed in Chapter 11. Chapter 12 offers a nongovernmental perspective on the general quality of drinking water and how this is affected by a wide range of drinking water treatment technologies. Separate abstracts are processed for 5 chapters in this book for inclusion in the appropriate data bases

Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants.

Science.gov (United States)

Park, Donguk; Leem, Jonghan; Lee, Kyoungmu; Lim, Heungkyu; Choi, Yeyong; Ahn, Jong-Ju; Lim, Sinye; Park, Jeongim; Choi, Kyungho; Lee, Naroo; Jung, Hyejung; Ha, Jongsik; Paek, Domyung

2014-09-02

This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13-50 years) who used disinfectant added to humidifiers in the home. Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. Nine of the patients (three pregnant females, six preschool-age children) died soon after they first developed lung damage. Six (16%) were pregnant females and 22 (58%) were preschool-aged children younger than six years. The patients used humidifier disinfectant products containing either polyhexamethylene guanidine phosphate (PHMG, n = 36) or oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH, n = 2). Twenty-six patients (68%) used the brand "Oxy"®, which contains PHMG. Of the ten patients with fatal lung injury, nine were found to have used PHMG. Our findings suggest that the use of humidifier disinfectant products containing either PGH or PHMG can cause lung injury, especially in preschool-age children younger than six years and pregnant women.

The effects of chemical additives on the production of disinfection byproducts and ecotoxicity in simulated ballast water

Science.gov (United States)

Park, Chul; Cha, Hyung-Gon; Lee, Ji-Hyun; Choi, Tae Seop; Lee, Jungsuk; Kim, Young-Hee; Bae, Minjung; Shin, Kyoungsoon; Choi, Keun-Hyung

2017-11-01

The management of ship ballast water is essential to stemming the introduction of non-indigenous species. Approval for onboard installation of a system to treat ballast water requires rigorous land-based testing as dictated in the G8 guideline by the International Maritime Organization. However, this testing lacks standardization-most notably augmentation of organic carbon for influent water by adding chemical additives. Electrochlorination is a popular treatment method for ballast water, in which chlorinated oxidants react with organisms and organic matter in water. The additives could thus affect the treatment efficacy of the ballast water. Here, we examined the effects of several candidates of organic carbon additives on the consumption of total residual oxidant (TRO), the production of disinfection byproducts (DBPs), plankton survival, and ecotoxicity. The TRO consumption over five days of storage was higher in electrochlorinated seawater amended with lignin and Metamucil when compared with seawaters with other organic carbon compounds. DBP production varied by almost two orders of magnitude as a function of the various additives. This was largely attributed to the production of tribromomethane and dibromoacetic acid. The survival of Artemia franciscana was significantly different across waters of different organic carbon additives. Algal toxicity testing with the marine haptophyte Isochrysis galbana significantly reduced growth in lignin- and Metamucil-treated seawaters, but not with other organic carbon compounds. Bioluminescence in Vibrio fischeri sharply declined in electrochlorinated seawaters with all types of organic carbon compounds, but no toxicity was manifested once the electrochlorinated seawaters were neutralized with sodium thiosulfate. The varying degrees of outcome suggest that it might be better to eliminate the requirements of adding organic carbon to test water as long as natural water was used for land-based testing of BWMS. If needed, the

Technical and economical feasibility study of a sewage sludge disinfection plants by irradiation process

International Nuclear Information System (INIS)

Rojas Bustos, Gustavo

1999-01-01

This report presents a technical and economical evaluation for a disinfection plant of sewage sludge based on irradiation. The process starts after sludge stabilization which is achieved by anaerobic digestion. It includes two stages, plus an optional: the first corresponds to dewatering of sewage sludge up to a solids content between 20 and 25 %, the second stage corresponds to disinfection by gamma or electron beam irradiation, and the third, which is optional, corresponds to the drying of sewage sludge up to a water content of 50%, which allows to diminish significantly the volumes of solids to be transported. If this stage is not accomplished the final product corresponds to a sewage sludge with 25 % of dry solids, which can also be disposed in agricultural land. Process was designed to treat 60 tons per day of sewage sludge (dry matter basis). The report presents the design of process equipment, principal and auxiliary, the investment and operational cost estimations as well as the total cost of treatment per ton of sewage sludge. A sensitivity analysis is also included to determine the influence of operational process parameters in operational and investment costs. The results showed that a sewage sludge plant including dewatering and disinfection process through gamma irradiation, achieves a capital investment of about US$ 12.000.000 with a treatment cost per ton of dry sludge of US$140. Including the optional air-drying stage, the total cost of treatment is about US$148 per ton of dry matter. In the case of electron beam irradiation the capital investment achieves a value of US$ 11 millions with a total treatment cost of US$ 136 per ton of dry matter. These values resulted quite similar to the cost of alternative treatment, i.e., disposal in a dedicated landfill. (L.V.)

Demonstration of disinfection procedure for the development of accurate blood glucose meters in accordance with ISO 15197:2013

Science.gov (United States)

Lin, Wen-Ye; Chang, Jung-Tzu; Chu, Chun-Feng

2017-01-01

Despite measures to reduce disease transmission, a risk can occur when blood glucose meters (BGMs) are used on multiple individuals or by caregivers assisting a patient. The laboratory and in-clinic performance of a BGM system before and after disinfection should be demonstrated to guarantee accurate readings and reliable control of blood glucose (BG) for patients. In this study, an effective disinfection procedure, conducting wiping 10 times to assure a one minute contact time of the disinfectant on contaminated surface, was first demonstrated using test samples of the meter housing materials, including acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polycarbonate (PC), in accordance with ISO 15197:2013. After bench studies comprising 10,000 disinfection cycles, the elemental compositions of the disinfected ABS, PMMA, and PC samples were almost the same as in the original samples, as indicated by electron spectroscopy for chemical analysis. Subsequently, the validated disinfection procedure was then directly applied to disinfect 5 commercial BGM systems composed of ABS, PMMA, or PC to observe the effect of the validated disinfection procedure on meter accuracy. The results of HBsAg values after treatment with HBV sera and disinfectant wipes for each material were less than the LoD of each material of 0.020 IU/mL. Before and after the multiple disinfection cycles, 900 of 900 samples (100%) were within the system accuracy requirements of ISO 15197:2013. All of the systems showed high performance before and after the series of disinfection cycles and met the ISO 15197:2013 requirements. In addition, our results demonstrated multiple cleaning and disinfection cycles that represented normal use over the lifetime of a meter of 3–5 years. Our validated cleaning and disinfection procedure can be directly applied to other registered disinfectants for cleaning commercial BGM products in the future. PMID:28683148

Effects of disinfection of combined agar/alginate impressions on the dimensional accuracy of stone casts.

Science.gov (United States)

Hiraguchi, Hisako; Nakagawa, Hisami; Kaketani, Masahiro; Hirose, Hideharu; Nishiyama, Minoru

2007-05-01

This study investigated the effects of disinfection of combined agar/alginate impressions on the dimensional accuracy of resultant stone casts. Impressions of a master cast designed to simulate an abutment tooth were prepared by combining each of two brands of cartridge-form agar impression materials with an alginate impression material. The impressions were immersed in 1% sodium hypochlorite for 10 minutes or 2% glutaraldehyde for 30 minutes. The remaining impressions were sprayed with these two disinfectants and then stored in sealed bags for 10, 30, 60, and 120 minutes. Stone casts obtained from the non-disinfected impressions were also prepared as control. Changes in diameter of the stone casts were then measured. Results indicated that storage for 10 minutes after spraying with 1% sodium hypochlorite was an appropriate disinfection method for combined agar/alginate impressions, as well as immersion in 1% sodium hypochlorite for 10 minutes.

Spiral-shaped reactor for water disinfection

KAUST Repository

Soukane, Sofiane; Ait-Djoudi, Fariza; Naceur, Wahib M.; Ghaffour, NorEddine

2016-01-01

Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria

Cleaning and disinfection programs against Campylobacter jejuni for broiler chickens: productive performance, microbiological assessment and characterization1

Science.gov (United States)

Deliberali Lelis, Karoline; Granghelli, Carlos Alexandre; Carão de Pinho, Agatha Cristina; Ribeiro Almeida Queiroz, Sabrina; Fernandes, Andrezza Maria; Moro de Souza, Ricardo Luiz; Gaglianone Moro, Maria Estela; de Andrade Bordin, Roberto; de Albuquerque, Ricardo

2017-01-01

Abstract Detailed cleaning and disinfection programs aims to reduce infection pressure from microorganisms from one flock to the next. However, studies evaluating the benefits to poultry performance, the sanitary status of the facilities, and the sanitary quality of the meat are rarely found. Thus, this study was designed to evaluate 2 cleaning and disinfecting programs regarding their influence on productive performance, elimination of Campylobacter, and characterization of Campylobacter jejuni strains when applied to broiler chickens’ facilities. Two subsequent flocks with 960 birds each were distributed into 32 pens containing 30 birds each. In the first, the whole flock was inoculated with a known strain of Campylobacter jejuni in order to contaminate the environment. In the second flock, performance and microbiological evaluations were done, characterizing an observational study between 2 cleaning and disinfection programs, regular and proposed. The regular program consisted of sweeping facilities, washing equipment and environment with water and neutral detergent. The proposed cleaning program consisted of dry and wet cleaning, application of 2 detergents (one acid and one basic) and 2 disinfectants (250 g/L glutaraldehyde and 185 g/L formaldehyde at 0.5% and 210 g/L para-chloro-meta-cresol at 4%). Total microorganism count in the environment and Campylobacter spp. identification were done for the microbiological assessment of the environment and carcasses. The positive samples were submitted to molecular identification of Campylobacter spp. and posterior genetic sequencing of the species identified as Campylobacter jejuni. The birds housed in the facilities and submitted to the proposed treatment had better performance when compared to the ones in the regular treatment, most likely because there was a smaller total microorganism count on the floor, walls, feeders and drinkers. The proposed program also resulted in a reduction of Campylobacter spp. on

Adding silver and copper to hydrogen peroxide and peracetic acid in the disinfection of an advanced primary treatment effluent.

Science.gov (United States)

Orta De Velásquez, M T; Yáñez-Noguez, I; Jiménez-Cisneros, B; Luna Pabello, V M

2008-11-01

This paper evaluates the efficacy of hydrogen peroxide (HP) and peracetic acid (PAA) in the disinfection of an Advanced Primary Treatment (APT) effluent, and how said disinfection capacities can be enhanced by combining the oxidants with copper (Cu2+) and silver (Ag). The treatment sequence consisted of APT (adding chemicals to water to remove suspended solids by coagulation and flocculation), followed by disinfection with various doses of HP, HP+Cu2+, HP+Ag, PAA and PAA+Ag. Microbiological quality was determined by monitoring concentrations of fecal coliforms (FC), pathogenic bacteria (PB) and helminth eggs (HE) throughout the sequence. The results revealed that APT effluent still contains very high levels of bacteria as the treatment only removes 1-2 log of FC and PB, but the reduction in the number of viable helminth eggs was 83%. Subsequent disinfection stages demonstrated that both HP+Cu2+ and HP+Ag have a marked disinfection capacity for bacteria (3.9 and 3.4 log-inactivation, respectively). Peracetic acid on its own was already extremely efficient at disinfecting for bacteria, and the effect was enhanced when combining PAA with silver (PAA+Ag). The best result for HE removal was achieved by combining PAA with silver (PAA+Ag) at doses of 20 + 2.0 mg l(-1), respectively. The study concluded that the PAA+Ag and HP+Ag combinations were good alternatives for APT effluent disinfection, because the disinfected effluents met the standards in NOM-001-SEMARNAT-1996, Mexico's regulation governing the microbiological quality required in treated wastewater destined for unrestricted reuse in agricultural irrigation (disinfection treatments with a primary method such as APT, therefore, offers an effective and practical way of reducing the health risks normally associated with the reuse of wastewaters.

Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

Energy Technology Data Exchange (ETDEWEB)

Beltrán-Partida, Ernesto [Department of Biomaterials, Dental Materials and Tissue Engineering, Faculty of Dentistry Mexicali, Autonomous University of Baja California, Av. Zotoluca and Chinampas St., 21040 Mexicali, Baja California (Mexico); Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Benjamín, E-mail: benval@uabc.edu.mx [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Escamilla, Alan; Curiel, Mario [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Ernesto [Ixchel Medical Centre, Av. Bravo y Obregón, 21000 Mexicali, Baja California (Mexico); Nedev, Nicola [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Bastidas, Jose M. [National Centre for Metallurgical Research, CSIC, Av. Gregorio del Amo 8, 28040 Madrid (Spain)

2016-03-01

Amorphous titanium dioxide (TiO{sub 2}) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO{sub 2} nanotubes.

Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

International Nuclear Information System (INIS)

Beltrán-Partida, Ernesto; Valdez-Salas, Benjamín; Escamilla, Alan; Curiel, Mario; Valdez-Salas, Ernesto; Nedev, Nicola; Bastidas, Jose M.

2016-01-01

Amorphous titanium dioxide (TiO_2) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO_2 nanotubes.

9 CFR 71.12 - Sodium orthophenylphenate as permitted disinfectant for premises infected with tuberculosis.

Science.gov (United States)

2010-01-01

... disinfectant for premises infected with tuberculosis. 71.12 Section 71.12 Animals and Animal Products ANIMAL... disinfectant for premises infected with tuberculosis. (a) A permitted brand of sodium orthophenylphenate in a proportion of at least one pound to 12 gallons of water is permitted in tuberculosis eradication work for...

Inactivation of influenza A virus H1N1 by disinfection process.

Science.gov (United States)

Jeong, Eun Kyo; Bae, Jung Eun; Kim, In Seop

2010-06-01

Because any patient, health care worker, or visitor is capable of transmitting influenza to susceptible persons within hospitals, hospital-acquired influenza has been a clinical concern. Disinfection and cleaning of medical equipment, surgical instruments, and hospital environment are important measures to prevent transmission of influenza virus from hospitals to individuals. This study was conducted to evaluate the efficacy of disinfection processes, which can be easily operated at hospitals, in inactivating influenza A virus H1N1 (H1N1). The effects of 0.1 mol/L NaOH, 70% ethanol, 70% 1-propanol, solvent/detergent (S/D) using 0.3% tri (n-butyl)-phosphate and 1.0% Triton X-100, heat, and ethylene oxide (EO) treatments in inactivating H1N1 were determined. Inactivation of H1N1 was kinetically determined by the treatment of disinfectants to virus solution. Also, a surface test method, which involved drying an amount of virus on a surface and then applying the inactivation methods for 1 minute of contact time, was used to determine the virucidal activity. H1N1 was completely inactivated to undetectable levels in 1 minute of 70% ethanol, 70% 1-propanol, and solvent/detergent treatments in the surface tests as well as in the suspension tests. H1N1 was completely inactivated in 1 minute of 0.1 mol/L NaOH treatment in the suspension tests and also effectively inactivated in the surface tests with the log reduction factor of 3.7. H1N1 was inactivated to undetectable levels within 5 minutes, 2.5 minutes, and 1 minute of heat treatment at 70, 80, and 90 degrees C, respectively in the suspension tests. Also, H1N1 was completely inactivated by EO treatment in the surface tests. Common disinfectants, heat, and EO tested in this study were effective at inactivating H1N1. These results would be helpful in implementing effective disinfecting measures to prevent hospital-acquired infections. Copyright 2010 Association for Professionals in Infection Control and Epidemiology, Inc

The role of surface disinfection in infection prevention

Science.gov (United States)

Gebel, Jürgen; Exner, Martin; French, Gary; Chartier, Yves; Christiansen, Bärbel; Gemein, Stefanie; Goroncy-Bermes, Peter; Hartemann, Philippe; Heudorf, Ursel; Kramer, Axel; Maillard, Jean-Yves; Oltmanns, Peter; Rotter, Manfred; Sonntag, Hans-Günther

2013-01-01

Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper. Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges. Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects. Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection. PMID:23967396

The role of surface disinfection in infection prevention

Directory of Open Access Journals (Sweden)

Gebel, Jürgen

2013-04-01

Full Text Available [english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

Genotoxicity analysis of two halonitromethanes, a novel group of disinfection by-products (DBPs), in human cells treated in vitro

International Nuclear Information System (INIS)

Liviac, Danae; Creus, Amadeu; Marcos, Ricard

2009-01-01

Halonitromethanes (HNMs) constitute an emerging class of disinfection by-products (DBPs) produced when chlorine and/or ozone are used for water treatment. The HNMs are structurally similar to halomethanes, but have a nitro-group in place of hydrogen bonded to the central carbon atom. Since little information exists on the genotoxic potential of HNMs, a study has been carried out with two HNM compounds, namely trichloronitromethane (TCNM) and bromonitromethane (BNM) by using human cells. Primary damage induction has been measured with the Comet assay, which is used to determine both the repair kinetics of the induced damage and the proportion of induced oxidative damage. In addition, the fixed DNA damage has been evaluated by using the micronucleus (MN) assay. The results obtained indicate that both compounds are genotoxic, inducing high levels of DNA breaks in the Comet assay, and that this DNA damage repairs well over time. In addition, oxidized bases constitute a high proportion of DNA-induced damage (50-75%). Contrarily, no positive effects were observed in the frequency of micronucleus, which measures both clastogenic and aneugenic effects, neither using TK6 cells nor peripheral blood lymphocytes. This lack of fixed genetic damage would minimize the potential mutagenic risk associated with HNMs exposure

Surface dielectric barrier discharge jet for skin disinfection

NARCIS (Netherlands)

Creyghton, Y.; Meijer, R.; Verweij, P.; Zanden, F. van der; Leenders, P.

2012-01-01

A consortium consisting of the research institute TNO, the medical -university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and

Disinfection of wastewater by hydrogen peroxide or peracetic acid: development of procedures for measurement of residual disinfectant and application to a physicochemically treated municipal effluent.

Science.gov (United States)

Wagner, Monika; Brumelis, Daina; Gehr, Ronald

2002-01-01

The Montreal Urban Community Wastewater Treatment Plant (MUCWTP) located in Montreal. Quebec, Canada, uses physicochemical treatment processes prior to discharging wastewater into the St. Lawrence River via an outfall tunnel of 2 hours retention time. Although chlorination facilities exist, they are not being used, and the MUCWTP is seeking alternative methods for disinfection to achieve a 2- to 3-log fecal coliform reduction. Liquid chemical disinfectants were attractive options because of their low capital costs. This led to an investigation of the feasibility of using hydrogen peroxide or peracetic acid. A method for measuring peroxycompounds (hydrogen peroxide or peracetic acid plus hydrogen peroxide) was developed using the peroxidase-based oxidation of 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfuric acid) diammonium salt (ABTS) with hydrogen peroxide. The validity of the method was confirmed using effluent from the MUCWTP. Recovery was higher than 90% for peracetic acid levels as low as 1.0 mg/L. Quenching of hydrogen peroxide was achieved with 50-mg/L catalase; quenching of peracetic acid was achieved with 100 mg/L of sodium thiosulfate, followed by 50 mg/L of catalase. Batch disinfection tests were conducted on MUCWTP effluent. Hydrogen peroxide and peracetic acid in wastewater over time could be modeled as a second-order decay, with the decay "constant" being a function of the initial concentration of peroxycompounds. This function was the same for both hydrogen peroxide and peracetic acid, possibly indicating similar decomposition pathways in wastewater matrices. Disinfection was modeled using a modified Hom equation. Required doses of hydrogen peroxide to reach the target fecal coliform levels ranged from 106 to 285 mg/L, with the higher doses occurring when ferric chloride instead of alum was used as the coagulant. Hence, hydrogen peroxide was infeasible as a disinfectant for this application. On the other hand, the peracetic acid dose needed to

The shadow of dichloroacetonitrile (DCAN), a typical nitrogenous disinfection by-product (N-DBP), in the waterworks and its backwash water reuse.

Science.gov (United States)

Tan, Yiwen; Lin, Tao; Jiang, Fuchun; Dong, Jian; Chen, Wei; Zhou, Dongju

2017-08-01

Dichloroacetonitrile (DCAN) is one of nitrogenous disinfection by-products (N-DBPs) with strong cytotoxicity and genotoxicity. In this study, the formation potential (FP) of DCAN was investigated in the samples of six important water sources located in the Yangtze River Delta. The highest formation concentration of DCAN was 9.05 μg/L in the water sample taken from Taihu Lake with the lowest SUVA value. After the NOM fractionation, the conversion rate of hydrophilic fraction to DCAN was found the highest. Subsequently, a waterworks using Taihu Lake as water source was chosen to research the FP variations of DCAN in the treatment process and backwash water. The results showed that, compared to the conventional treatment process, O/biological activated carbon (BAC) process increased the removal efficiency of DCAN from 21.89% to 50.58% by removing aromatic protein and soluble biological by-products as main precursors of DCAN. The DCAN FP in the effluent of BAC filters using old granular activated carbon was higher than that in the influent and the DCAN FP of its backwash water was lower than that in raw water. In the backwash water of sand filters, the DCAN FP higher than raw water required the recycle ratio less than 5% to avoid the accumulation of DCAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regulation of hydrogen production by Enterobacter aerogenes by external NADH and NAD{sup +}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chong; Ma, Kun; Xing, Xin-Hui [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2009-02-15

Experiments involving the addition of external nicotinamide adenine dinucleotide, reduced form (NADH) or nicotinamide adenine dinucleotide (NAD{sup +}) have been designed to examine how the hydrogen in Enterobacter aerogenes is liberated by NADH or NAD{sup +}. The addition of external NADH or NAD{sup +} was found to regulate hydrogen production by E. aerogenes in resting cells, batch cultures, and chemostat cultures. Particularly in chemostat cultivation, with the external addition of NADH, hydrogen production via the NADH pathway was decreased, while that via the formate pathway was increased; in the end, the overall hydrogen p was decreased. The addition of NAD{sup +}, on the other hand, gave the opposite results. The membrane-bound hydrogenase was found to play a central role in regulating hydrogen production. The occurrence of NADH oxidation (NAD{sup +} reduction) on the cell membrane resulted in an electron flow across the membrane; this changed the oxidation state and metabolic pattern of the cells, which eventually affected the hydrogen evolution. (author)

Persistence of mixed staphylococci assemblages following disinfection of hospital room surfaces.

Science.gov (United States)

Sigler, V; Hensley, S

2013-03-01

The distribution of staphylococcal assemblages on surfaces in hospital rooms was assessed before and after daily disinfection with quaternary ammonia products. DNA was extracted from enrichment cultures of bacteria, which were swabbed from each of nine surface types, and subjected to analysis by staphylococci-specific, denaturing gradient gel electrophoresis. A genetic marker for Staphylococcus epidermidis/kloosii was detected on all surface types before and after cleaning, whereas markers for Staphylococcus aureus and Staphylococcus lugdunensis were detected on five surface types. Overall, genetic makers for several staphylococci known to colonize and infect humans remained ubiquitous in each room following daily disinfection practices. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Electrochemically activated water as an alternative to chlorine for decentralized disinfection

KAUST Repository

Ghebremichael, Kebreab A.

2011-06-01

Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive oxygen species such as ozone and hydroxyl radicals in addition to chlorine. This study compares sodium hypochlorite (NaOCl) and ECA in terms of disinfection efficacy, trihalomethanes (THMs) formation, stability and composition. The studies were carried out under different process conditions (pH 5,7 and 9, disinfectant concentrations of 2-5 mg/L and dissolved organic carbon (DOC) concentration of 2-4 mg/L). The results indicated that in the presence of low DOC (<2 mg/L) ECA showed better disinfection efficacy for Escherichia coli inactivation, formed lower THM and had better stability compared with NaOCl at both pH 5 and 7. Stability studies of stock solutions showed that over a period of 30 days, ECA decayed by only 5% while NaOCl decayed by 37.5% at temperatures of 4 °C. In a fresh ECA of 200 mg/L chlorine, about 5.3 mg/L ozone and 36.9 mg/L ClO2 were detected. The study demonstrates that ECA could be a suitable alternative to NaOCl where decentralized production and use are required. © IWA Publishing 2011.

Chlorine dioxide as a disinfectant for Ralstonia solanacearum control in water, storage and equipment

Directory of Open Access Journals (Sweden)

Popović Tatjana

2016-01-01

Full Text Available Brown rot or bacterial wilt caused by bacterium Ralstonia solanacearum is the main limiting factor in potato production. Quarantine measures are necessary to avoid spread of disease to disease-free areas. R. solanacearum has been shown to contaminate watercourses from which crop irrigation is then prohibited causing further potential losses in yield and quality. The bacteria also spread via surfaces that diseased seed potatoes come into contact with. This study showed bactericidal activity of chlorine dioxide (CIO2 on R. solanacearum for disinfection of water, surface and equipment. The results showed that CIO2 solution at concentration of 2 ppm at 30 minutes of exposure time had bactericidal effect for disinfection of water. For surface and equipment disinfection, concentration of 50 ppm showed total efficacy at 30 min and 5 sec exposure time, respectively. Results suggest that use of CIO2 as a disinfectant has a potential for control of brown rot pathogen in water, storage and equipment.

Quantification of Helicobacter pylori in the viable but nonculturable state by quantitative PCR in water disinfected with ozone.

Science.gov (United States)

Casasola-Rodríguez, B; Orta de Velásquez, M T; Luqueño-Martínez, V G; Monje-Ramírez, I

2013-01-01

Helicobacter pylori is a Gram-negative spiral-shaped bacterium that colonizes the gastric mucosa and is associated with gastric diseases. It may present a morphological adaptation when it is out of its natural environment, such as in water. The morphological adaptation is a coccoid form, which is a viable but non-culturable state (VNC) in which the DNA remains active and therefore infective. Due to the impossibility of culture by traditional methods in the VNC state, we developed a methodology that includes a molecular technique, quantitative polymerase chain reaction (qPCR), which is capable of measuring the bacteria in both forms (helical and coccoidal) and therefore is able to measure a disinfection process and to estimate the resistance of the bacteria to ozone. The methodology developed measures the efficiency of the ozone disinfection when bacteria are in a VNC state only. Bacterial culture at 9 × 10(8)CFU/mL diluted in 40 mL reaction volumes were exposed to a wide range of CT values (0.11-15 mg min/L). The results show a 3.92-log reduction when treated with 15 mg min/L. Our results demonstrate the feasibility of using qPCR for the quantification and detection of H. pylori, in coccoid form, in water systems treated with an ozone disinfection process.

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

Science.gov (United States)

Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

2017-12-01

Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Science.gov (United States)

Wu, Siva; Li, Xiaojin; Gunawardana, Manjula; Maguire, Kathleen; Guerrero-Given, Debbie; Schaudinn, Christoph; Wang, Charles; Baum, Marc M.; Webster, Paul

2014-01-01

Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. PMID:25007395

Reductions of dissolved organic matter and disinfection by-product precursors in full-scale wastewater treatment plants in winter.

Science.gov (United States)

Xue, Shuang; Jin, Wujisiguleng; Zhang, Zhaohong; Liu, Hong

2017-07-01

The reductions of dissolved organic matter (DOM) and disinfection byproduct precursors in four full-scale wastewater treatment plants (WWTPs) (Liaoning Province, China) where different biological treatment processes were employed in winter were investigated. The total removal efficiencies of dissolved organic carbon (DOC), ultraviolet light at 254 nm (UV-254), trihalomethane formation potential (THMFP), and haloacetic acid formation potential (HAAFP) were in the range of 70.3-76.0%, 49.6-57.3%, 54.4-65.0%, and 53.7-63.8% in the four WWTPs, respectively. The biological treatment was the predominant process responsible for the removal of DOC, THMFP, and HAAFP in WWTPs. Differences in the reduction of UV-254 were not significant (p > 0.05) among biochemical reaction pool, secondary sedimentation tank, and disinfection tank. Biological aerated filter and suspended carrier activated sludge processes achieved higher DOM removal than the conventional active sludge and anaerobic-anoxic-oxic processes. Hydrophobic neutral and hydrophilic fraction were removed to a higher degree through biological treatment than the other three DOM fractions. HAAFP removal was more efficient than THMFP reduction during biological treatment. During primary treatment, fluorescent materials in secondary sedimentation tanks were preferentially removed, as compared to the bulk DOM. Humic-like fluorescent compounds were not readily eliminated during biological treatment. The fluorescent materials were more susceptible to chlorine than nonfluorescent compounds. Copyright © 2017. Published by Elsevier Ltd.

The effectiveness of a single-stage versus traditional three-staged protocol of hospital disinfection at eradicating vancomycin-resistant Enterococci from frequently touched surfaces.

Science.gov (United States)

Friedman, N Deborah; Walton, Aaron L; Boyd, Sarah; Tremonti, Christopher; Low, Jillian; Styles, Kaylene; Harris, Owen; Alfredson, David; Athan, Eugene

2013-03-01

Environmental contamination is a reservoir for vancomycin-resistant enterococcus (VRE) in hospitals. Environmental sampling of surfaces was undertaken anytime before disinfection and 1 hour after disinfection utilizing a sodium dichloroisocyanurate-based, 3-staged protocol (phase 1) or benzalkonium chloride-based, single-stage clean (phase 2). VRE colonization and infection rates are presented from 2010 to 2011, and audits of cleaning completeness were also analyzed. Environmental samples collected before disinfection were significantly more likely to be contaminated with VRE during phase 1 than phase 2: 25.2% versus 4.6%, respectively; odds ratio (OR), 7.01 (P benzalkonium chloride-based product for disinfection. This reduction in VRE may be due to a new disinfection product, more attention to the thoroughness of cleaning, or other supplementary efforts in our institution. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Comparison of organic peracids in wastewater treatment: Disinfection, oxidation and corrosion.

Science.gov (United States)

Luukkonen, Tero; Heyninck, Tom; Rämö, Jaakko; Lassi, Ulla

2015-11-15

The use of organic peracids in wastewater treatment is attracting increasing interest. The common beneficial features of peracids are effective anti-microbial properties, lack of harmful disinfection by-products and high oxidation power. In this study performic (PFA), peracetic (PAA) and perpropionic acids (PPA) were synthesized and compared in laboratory batch experiments for the inactivation of Escherichia coli and enterococci in tertiary wastewater, oxidation of bisphenol-A and for corrosive properties. Disinfection tests revealed PFA to be a more potent disinfectant than PAA or PPA. 1.5 mg L(-1) dose and 2 min of contact time already resulted in 3.0 log E. coli and 1.2 log enterococci reduction. Operational costs of disinfection were estimated to be 0.0114, 0.0261 and 0.0207 €/m(3) for PFA, PAA and PPA, respectively. Disinfection followed the first order kinetics (Hom model or S-model) with all studied peracids. However, in the bisphenol-A oxidation experiments involving Fenton-like conditions (pH = 3.5, Fe(2+) or Cu(2+) = 0.4 mM) peracids brought no additional improvement to traditionally used and lower cost hydrogen peroxide. Corrosion measurements showed peracids to cause only a negligible corrosion rate (<6 μm year(-1)) on stainless steel 316L while corrosion rates on the carbon steel sample were significantly higher (<500 μm year(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

Peracetic Acid as a Green Disinfectant for Combined Sewer ...

Science.gov (United States)

This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiveness of sodium hypochlorite and PAA for the inactivation of E. coli in CSO wastewater using laboratory bench-scale jar tests and Muddy Creek field site studies based on the following items:•Storage, shelf life, and application of the disinfectants.•Effectiveness of the disinfectants in the inactivation of E. coli.•Formation of harmful byproducts by the disinfectants.•Operation and maintenance costs, including the cost of the disinfectant, its storage, application, and neutralizing agent for the disinfectant to maintain the Ohio EPA guideline for residual disinfectant at the discharge point. Like many cities in the USA, Cincinnati, Ohio is attempting to find the best way to meet state and federal requirements concerning combined sewer overflow (CSO) wastewater. The Muddy Creek CSO treatment facility was constructed to provide treatment for CSO Numbers 198 and 216 from the Westwood Trunk sewer. The Metropolitan Sewer District of Greater Cincinnati (MSDGC) is currently using sodium hypochlorite for disinfection in this treatment facility. Because of degradation of hypochlorite during storage and the formation of chlorinated disinfection byproducts (DBPs), MSDGC is evaluating alternat

Study of the Interactions Between Bacteriophage phiIPLA-RODI and Four Chemical Disinfectants for the Elimination of Staphylococcus aureus Contamination

Directory of Open Access Journals (Sweden)

Seila Agún

2018-02-01

Full Text Available Bacteriophages are currently considered as a promising alternative to antibiotics and disinfectants. However, the use of phages in different clinical and industrial settings will involve their exposure to other disinfectants. As a result, the outcome of the phage treatment will depend on two aspects derived from such interactions. On the one hand, the susceptibility of the phage to disinfectants at the concentrations used for disinfection and at lower residual concentrations needs to be determined. Additionally, the existence of synergistic or antagonistic interactions between phages and disinfectants would also affect the potential success of phage biocontrol applications. Here, we tested these effects for the antistaphylococcal phage phiIPLA-RODI by using four different disinfectants: benzalkonium chloride, triclosan, chlorhexidine and hydrogen peroxide. Our results highlight the differences between disinfectants regarding their effect on phage survival and antimicrobial properties. For instance, our data suggests that, out of the four disinfectants used, benzalkonium chloride would be the most adequate to use in settings where phages are to be applied. Nonetheless, this preliminary analysis grants the need for further studies with a larger number of disinfectants for the development of a phiIPLA-RODI-based product.

Management practices in Australasian ethical investment products: a role for regulation?

DEFF Research Database (Denmark)

Haigh, Matthew; Guthrie, James

2010-01-01

This paper adds to the literatures on socially responsible investment (SRI), investment management, regulation of financial services and social accounting by providing a comprehensive survey of investment methods used in SRI products and regulated social reporting in financial services. Australian...... a four-year period: 2004-2007. These aspects were further examined in 18 case studies. Over the period, diversity and intensity of construction methods had increased both within and between investment managers. The non-standard nature of management consultation used in SRI products, marketing needs...... debates and other public reports. Portfolio construction styles of 86 SRI products managed by 63 financial institutions in Australia and New Zealand were chosen for analysis. Statistical analysis was conducted to identify associations between styles, construction methods and assessment techniques over...

A Summary of Publications on the Development of Mode-of-Action Information and Statistical Tools for Evaluating Health Outcomes from Drinking Water Disinfection By-Product (DBP) Exposures

Science.gov (United States)

Chemical contaminants are formed as a consequence of chemical disinfection of public drinking waters. Chemical disinfectants, which are used to kill harmful microorganisms, react with natural organic matter (NOM), bromide, iodide, and other compounds, forming complex mixtures...

The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

Science.gov (United States)

Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

2016-08-01

Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

Impact of disinfection on drinking water biofilm bacterial community.

Science.gov (United States)

Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

2015-11-01

Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination. Copyright © 2015. Published by Elsevier B.V.

Effect of disinfection on irreversible hydrocolloid and alternative impression materials and the resultant gypsum casts.

Science.gov (United States)

Suprono, Montry S; Kattadiyil, Mathew T; Goodacre, Charles J; Winer, Myron S

2012-10-01

Many new products have been introduced and marketed as alternatives to traditional irreversible hydrocolloid materials. These alternative materials have the same structural formula as addition reaction silicone, also known as vinyl polysiloxane (VPS), impression materials. Currently, there is limited in vitro and in vivo research on these products, including on the effects of chemical disinfectants on the materials. The purpose of this study was to compare the effects of a spray disinfecting technique on a traditional irreversible hydrocolloid and 3 new alternative impression materials in vitro. The tests were performed in accordance with the American National Standards Institute/American Dental Association (ANSI/ADA) Specification Nos. 18 and 19. Under standardized conditions, 100 impressions were made of a ruled test block with an irreversible hydrocolloid and 3 alternative impression materials. Nondisinfected irreversible hydrocolloid was used as the control. The impressions were examined for surface detail reproduction before and after disinfection with a chloramine-T product. Type III and Type V dental stone casts were evaluated for linear dimensional change and gypsum compatibility. Comparisons of linear dimensional change were analyzed with 2-way ANOVA of mean ranks with the Scheffé post hoc comparisons (α=.05). Data for surface detail reproduction were analyzed with the Wilcoxon Signed-Rank procedure and gypsum compatibility with the Kruskal-Wallis Rank procedure (α=.05). The alternative impression materials demonstrated significantly better outcomes with all 3 parameters tested. Disinfection with chloroamine-T did not have any effect on the 3 alternative impression materials. The irreversible hydrocolloid groups produced the most variability in the measurements of linear dimensional change. All of the tested materials were within the ADA's acceptable limit of 1.0% for linear dimensional change, except for the disinfected irreversible hydrocolloid

Non-traditional alternatives project for the control of dental biofilm alternative substances with antibacterial action for the disinfection of cavities

International Nuclear Information System (INIS)

Alfaro Mendez, Daniela; Correa Herrera, Graciela; Rivas Dona, Carmina

2013-01-01

The extracts of medicinal plants found in Costa Rica such as hawthorn, garlic and black tea were compared with Concepsis®, a product based on chlorhexidine used for the disinfection of dental cavities. The efficacy of the three plants was measured against S. mutans in in vitro cultures. Chlorhexidine has a higher bacteriostatic and bactericidal activity than the extracts of the three plants used, being the most effective agent against S. mutans [es

Applying a uniform layer of disinfectant by wiping.

Science.gov (United States)

Cooper, D W

2000-01-01

Disinfection or sterilization often requires applying a film of liquid to a surface, frequently done by using a wiper as the applicator. The wiper must not only hold a convenient amount of liquid, it must deposit it readily and uniformly. Contact time is critical to disinfection efficacy. Evaporation can limit the contact time. To lengthen the contact time, thickly applied layers are generally preferred. The thickness of such layers can be determined by using dyes or other tracers, as long as the tracers do not significantly affect the liquid's surface tension and viscosity and thus do not affect the thickness of the applied layer. Alternatively, as done here, the thickness of the layer can be inferred from the weight loss of the wiper. Results are reported of experiments on thickness of the layers applied under various conditions. Near saturation, hydrophilic polyurethane foam wipers gave layers roughly 10 microns thick, somewhat less than expected from hydrodynamic theory, but more than knitted polyester or woven cotton. Wipers with large liquid holding capacity, refilled often, should produce more nearly uniform layers. Higher pressures increase saturation in the wiper, tending to thicken the layer, but higher pressures also force liquid from the interface, tending to thin the layer, so the net result could be thicker or thinner layers, and there is likely to be an optimal pressure.

9 CFR 91.41 - Cleaning and disinfecting of aircraft.

Science.gov (United States)

2010-01-01

... of this chapter. The time at which the cleaning and disinfection is performed must be approved by the inspector, who will give approval only if he or she determines that the cleaning and disinfection will be... time, the inspector shall determine whether further cleaning and disinfection are necessary. The...

Overview of the current National Primary Drinking Water Regulations and regulation development process

International Nuclear Information System (INIS)

Cotruvo, J.A.; Regelski, M.

1989-01-01

The promulgation of the National Primary Drinking Water Regulations (NPDWR) follows specific steps. First, the Advance Notice of Proposed Rule Making (ANPRM) is published. Second, the EPA, as mandated by the SDWA Amendments, proposes maximum contaminant levels (MCLs), (enforceable standards) and maximum contaminant level goals (MCLGs) simultaneously. The Office of Drinking Water developed a six-phase schedule that has attempted to parallel the SDWA-specified deadlines: Phase I - Voltile organic chemicals - July 8, 1987; Phase II - Synthetic organic chemicals and inorganic chemicals - June 1989, microbials and surface water treatment - June 1989, and Lead/copper - December 1988; Phase III - Radionuclides - December 1988; Phase IV - Disinfectants and disinfection by-products - June 1989; Phase V - Other inorganic chemicals, synthetic organic chemicals, and pesticides - June 1989; and Phase VI - 25 additional chemicals - January 199. In selecting contaminants for regulation, the most relevant criteria are (1) potential health risk; (2) ability to detect a contaminant in the drinking water; and (3) occurrence or potential occurrence in drinking water. The EPA uses a three category approach for setting maximum contaminant level goals for carcinogens: Category I, strong evidence of carcinogenicity-zero; Category II, equivocal evidence - reference dose (RfD) approach or 0.00001 to 0.000001 cancer risk range; and Category III, inadequate or no evidence from animal studies - RfD approach. 10 refs., 5 tabs

Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

Science.gov (United States)

Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

2011-01-01

High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

Synergistic effect of solar radiation and solar heating to disinfect drinking water sources.

Science.gov (United States)

Rijal, G K; Fujioka, R S

2001-01-01

Waterborne diseases are still common in developing countries as drinking water sources are contaminated and feasible means to reliably treat and disinfect these waters are not available. Many of these developing countries are in the tropical regions of the world where sunlight is plentiful. The objective of this study was to evaluate the effectiveness of combining solar radiation and solar heating to disinfect contaminated water using a modified Family Sol*Saver System (FSP). The non-UV transmittable cover sheet of the former FSP system was replaced with an UV transmittable plastic cover sheet to enable more wavelengths of sunlight to treat the water. Disinfection efficiency of both systems was evaluated based on reduction of the natural populations of faecal coliform, E. coli, enterococci, C. perfringens, total heterotrophic bacteria, hydrogen sulphide producing bacteria and FRNA virus. The results showed that under sunny and partly sunny conditions, water was heated to critical temperature (60 degrees C) in both the FSP systems inactivating more than 3 log (99.9%) of the concentrations of faecal coliform and E. coli to undetectable levels of heat worked synergistically to enhance the inactivation of faecal indicator bacteria. The relative log removal of indicator microorganism in the FSP treated water was total heterotrophic bacteria heat and radiation effects of sunlight were important in disinfecting water by solar units. The data indicated that direct radiation of sunlight worked synergistically with solar heating of the water to disinfect the water. Thus, effective disinfection was observed even when the water temperature did not reach 60 degrees C. Finally, the hydrogen sulphide test is a simple and reliable test that householders can use to determine whether their water had been sufficiently disinfected.

Antibacterial Efficiency of Benzalkonium Chloride Base Disinfectant According To European Standard 13727, Chemical Analysis and Validation Studies

OpenAIRE

Yıldırım, Çinel; Çelenk, Veysel

2018-01-01

Antibacterial Efficiency of Benzalkonium Chloride Base Disinfectant According To European Standard 13727, Chemical Analysis and Validation Studies This study was aimed to provide principle of the chemical analyses, antibacterial efficiency test and validation procedures of the most commonly used benzalkonium chloride (BAC) base disinfectant as a biocide. Disinfectant which comprised 20 % BAC concentration was used as a prototype product and active substance was verified with chemical analysis...

Optimization of Chlorination Process for Mature Leachate Disinfection Using Response Surface Methodology

Directory of Open Access Journals (Sweden)

Hamzeh Ali Jamali1

2014-06-01

Full Text Available Background: leachate from landfill contains high level of microbial pathogens which is considered as one of the most important threats for the environment. One of the common and simple methods for water and wastewater disinfection is chlorination, but it rarely has been used for leachate disinfection. The objective of this study was evaluating the efficiency of chlorine for leachate disinfection and optimization of the effect of concentration and contact time on the death of total and fecal coliforms, as a microbial contamination index. Methods: In this descriptive-analysis study, microbial indices monitoring in leachates initiated from landfill of Qazvin city were conducted for one year. After pre-tests, the range of chlorine concentration and contact time on the inactivation of microbial indices were determined. Central composite design (CCD and response surface methodology (RSM were applied to optimize chlorine concentration and contact time parameters effect on microbial inactivation. 13 runs of tests were performed on samples. Tests were included BOD, COD, total and fecal coliforms. All analytical experiments were according to the standard methods for the examination of water and wastewater. Results: Results of the study showed that microbial indices had relatively high sensitivity to inactivation by chlorination, which in the chlorine concentration of 2 mg/L and contact time of 9 min, and chlorine concentration of 0.5 mg/L and contact time of 12 min, 100% of total and fecal coliforms inactivated, respectively. The RSM method was used for analysis of bacterial inactivation. Analyses showed that in contact time of 9.4 min and chlorine concentration of 2.99 mg/L, the inactivation efficiency of total and fecal coliforms were 89.16% and 100%, respectively. Conclusions: Chlorine could be used for leachate disinfection. However, in high concentrations of organic matter in leachates, due to production potential of chlorination by-products, health

Acrolein Exposure in Hookah Smokers and Non-Smokers Exposed to Hookah Tobacco Secondhand Smoke: Implications for Regulating Hookah Tobacco Products.

Science.gov (United States)

Kassem, Nada O F; Kassem, Noura O; Liles, Sandy; Zarth, Adam T; Jackson, Sheila R; Daffa, Reem M; Chatfield, Dale A; Carmella, Steven G; Hecht, Stephen S; Hovell, Melbourne F

2018-03-06

Acrolein is a highly ciliatoxic agent, a toxic respiratory irritant, a cardiotoxicant, and a possible carcinogen present in tobacco smoke including hookah tobacco. 105 hookah smokers and 103 non-smokers attended exclusively hookah smoking social events at either a hookah lounge or private home, and provided urine samples the morning of and the morning after the event. Samples were analyzed for 3-hydroxypropylmercapturic acid (3-HPMA), a metabolite of acrolein. Geometric mean (GM) urinary 3-HPMA levels in hookah smokers and non-smokers exposed to secondhand smoke (SHS) increased significantly, 1.41 times, 95% CI = 1.15 to 1.74 and 1.39 times, 95% CI = 1.16 to 1.67, respectively, following a hookah social event. The highest increase (1.68 times, 95% CI = 1.15 to 2.45; p = 0.007) in 3-HPMA post a hookah social event was among daily hookah smokers (GM, from 1991 pmol/mg to 3348 pmol/mg). Pre-to-post event change in urinary 3-HPMA was significantly positively correlated with pre-to-post event change in urinary cotinine among hookah smokers at either location of hookah event, (ρ = 0.359, p = 0.001), and among non-smokers in hookah lounges (ρ = 0.369, p = 0.012). Hookah tobacco smoke is a source of acrolein exposure. Findings support regulating hookah tobacco products including reducing humectants and sugar additives, which are precursors of acrolein under certain pyrolysis conditions. We suggest posting health warning signs for indoor smoking in hookah lounges, and encouraging voluntary bans of smoking hookah tobacco in private homes. Our study is the first to quantify the increase in acrolein exposure in hookah smokers and non-smokers exposed to exclusively hookah tobacco SHS at hookah social events in homes or hookah lounges. Our findings provide additional support for regulating hookah tobacco product content, protecting non-smokers' health by posting health warning signs for indoor smoking in hookah lounges, and encouraging home bans on hookah tobacco smoking to

Efficacy of Cleaning and Disinfection Procedures in a Zebrafish (Danio rerio) Facility

OpenAIRE

Garcia, Rachel L; Sanders, George E

2011-01-01

Appropriate cleaning and disinfection procedures in zebrafish (Danio rerio) laboratories are crucial in preventing the spread of aquatic animal pathogens and minimizing the build-up of waste products and biologic matter. The procedures selected should accomplish these goals and incorporate the individual needs of various laboratories. In this study of a single zebrafish facility, we assessed the efficacy of 2 different cleaning and disinfection procedures for nets, tanks, and lids. ATP levels...

Full scale evaluation of combined sewer overflows disinfection using performic acid in a sea-outfall pipe

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar; Flagstad, Rasmus; Sonne Munch, Ebbe

2015-01-01

methods are known and each has problems. This work evaluated for the first time the full-scale disinfection using performic acid by the removal of the two currently regulated indicator bacteria for bathing water quality, E. coli and Enterococcus. Experiments were performed at a sewage bypass through a sea......-outfall pipe with a minimum hydraulic retention time of 24 min. The disinfection efficiency in the field was measured by analyzing samples taken before and after the treatment. Samples were also treated with performic acid in the laboratory to measure the disinfection effectiveness and kinetic of degradation...... of performic acid. Doses of 1-8 ppm of performic acid achieved 1.0-3.5 log removal of E coli and 1.0-2.44 log removal of Enterococcus in the field, but were somewhat higher in laboratory conditions at 1.69-4.38 and 1.0-4.27 log units, respectively. Studies of the degradation of performic acid in collected real...

Humidifier disinfectants, unfinished stories

Directory of Open Access Journals (Sweden)

Yeyong Choi

2016-02-01

Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

Environmental cleaning and disinfection.

Science.gov (United States)

Traverse, Michelle; Aceto, Helen

2015-03-01

The guidelines in this article provide veterinarians, veterinary technicians, and veterinary health care workers with an overview of evidence-based recommendations for the best practices associated with environmental cleaning and disinfection of a veterinary clinic that deals with small animals. Hospital-associated infections and the control and prevention programs necessary to alleviate them are addressed from an environmental perspective. Measures of hospital cleaning and disinfection include understanding mechanisms and types of contamination in veterinary settings, recognizing areas of potential concern, addressing appropriate decontamination techniques and selection of disinfectants, the management of potentially contaminated equipment, laundry, and waste management, and environmental surveillance strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

Beta- lactam antibiotics stimulate biofilm formation in non-typeable haemophilus influenzae by up-regulating carbohydrate metabolism.

Directory of Open Access Journals (Sweden)

Siva Wu

Full Text Available Non-typeable Haemophilus influenzae (NTHi is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended.

Resistance of Pseudomonas aeruginosa to liquid disinfectants on contaminated surfaces before formation of biofilms.

Science.gov (United States)

Sagripanti, J L; Bonifacino, A

2000-01-01

A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.

Peracetic acid in the disinfection of a hospital water system contaminated with Legionella species.

Science.gov (United States)

Ditommaso, Savina; Biasin, Cinzia; Giacomuzzi, Monica; Zotti, Carla Maria; Cavanna, Alberto; Ruggenini Moiraghi, Angela

2005-05-01

To assess the efficacy of an alternative disinfection method for hospital water distribution systems contaminated with Legionella. Disinfection with peracetic acid was performed in a small hospital contaminated with L. pneumophila serotype 1. The disinfectant was used at concentrations of 50 ppm (first three surveillance phases) and 1,000 ppm (fourth surveillance phase) for 30 minutes. Environmental monitoring revealed that disinfection was maintained 1 week after treatment; however, levels of recontamination surpassing baseline values were detected after approximately 1 month. Comparison of water temperatures measured at the distal outlets showed a statistically significant association between temperature and bacterial load. The circulating water temperature was found to be lower in the two wards farthest away from the hot water production plant than in other wards. It was thought that the lower water temperature in the two wards promoted the bacterial growth even after disinfection. Peracetic acid may be useful in emergency situations, but does not provide definitive protection even if used monthly.

Comparative Evaluation of Tensile Strength in Die Stone Incorporated with Sodium and Calcium Hypochlorite as Disinfectants: An in vitro Study.

Science.gov (United States)

Pramodh, N R; Kumar, C N Vijay; Pradeep, M R; Naik, Ravi; Mahesh, C S; Kumari, Manju R

2017-12-01

The aim of this study was to evaluate the tensile strength of die stone incorporated with sodium and calcium hypochlorite as disinfectants. Two commercially available type IV die stone (Kalrock: Kalabhai Karson Pvt., Ltd and Pearlstone: Asian Chemicals) and two commercially available disinfectant solutions (sodium hypochlorite and calcium hypochlorite: Beachem Laboratory Chemical Private Limited, Chennai and Leo Chem Private Limited, Bengaluru) were used in this study, and the tensile strength was measured using Lloyd's Universal Testing Machine. The results show that incorporating the disinfecting solutions decreases the tensile strength of both products. The effect of decreasing tensile strength on type IV gypsum product is seen more in calcium hypochlorite when compared with sodium hypochlorite disinfecting solution, and the tensile strength of Kalrock specimens is higher than Pearlstone specimens after disinfecting with sodium hypochlorite and calcium hypochlorite solution. The statistical results also show significant results in all the groups when compared with the control group. The incorporation of sodium and calcium hypochlorite disinfecting solutions is not an encouraging method for both die materials as it reduces the tensile strength of type IV gypsum product. Tensile strength of Kalstone® die material is superior than Pearlstone® die material after mixing with sodium hypochlorite and calcium hypochlorite. According to the recommendations of Americans with Disability Act (ADA) and the Centers for Disease Control and Prevention, disinfecting the whole cast without or minimal changes in physical and mechanical properties was the motto of the study. The tensile strength in type IV gypsum product plays a most important role in retrieval of cast from impression, especially in narrow tooth preparation. This study reveals that incorporating method of disinfecting solutions is not recommended as it reduces the tensile strength.

Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acid.

Science.gov (United States)

Bore, E; Langsrud, S

2005-01-01

To characterize micro-organisms isolated from Norwegian dairy production plants after cleaning and fogging disinfection with alkyl amine/peracetic acid and to indicate reasons for survival. Microbial samples were collected from five dairy plants after cleaning and fogging disinfection. Isolates from two of these production plants, which used fogging with alkylamino acetate (plant A), and peracetic acid (plant B), were chosen for further characterization. The sequence of the 16S ribosomal DNA, fatty acid analysis and biochemical characteristics were used to identify isolates. Three isolates identified as Rhodococcus erythropolis, Methylobacterium rhodesianum and Rhodotorula mucilaginosa were isolated from plant A and one Sphingomonas sp. and two M. extorquens from plant B. Different patterns of resistance to seven disinfectants in a bactericidal suspension test and variable degree of attachment to stainless steel were found. The strains with higher disinfectant resistance showed lower degree of attachment than susceptible strains. The study identifies and characterizes micro-organisms present after cleaning and fogging disinfection. Both surface attachment and resistance were shown as possible reasons for the presence of the isolates after cleaning and disinfection. These results contribute to the awareness of disinfectant resistance as well as attachment as mechanisms of survival in dairy industry. It also strengthens the argument of frequent alternation of disinfectants in the food processing industry to avoid the establishment of resistant house strains.

Effect of bactericidal activity of three disinfectants on methicillin-resistant Staphylococcus aureus (MRSA

Directory of Open Access Journals (Sweden)

Cesar Augusto Marchionatti Avancini

2017-05-01

Full Text Available Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA can cause hospital-acquired infections (HA-MRSA, community- acquired ones (CA-MRSA, and infections transmitted by pets and animals raised for food production (livestock-acquired or LA-MRSA. The conduct to control the transmission of these diseases requires a careful action against the causative agents on surfaces in the environment and the choice of disinfectants and antiseptics is crucial. The objective of the present study was to evaluate the effect of the bactericidal activity of sodium hypochlorite (SH, iodophor (I and a quaternary ammonium compound (QAC, cetyl-trimethyl-ammonium chloride, commonly used in hospital and animal production settings, on 21 MRSA isolates and a control bacterium, and test the hypothesis of cross resistance of antibiotics and disinfectants. Methods: The bactericidal activity of four successive dilutions of the disinfectants was evaluated through the suspension test, using an initial inoculum population density of 107 CFU/mL, after contact times of 5, 15 and 30 minutes. Results: Five minutes of contact of SH 25 ppm, I 12.5 ppm and QAC 125 ppm sufficed to inactivate the reference bacterium S. aureus ATCC 6538 and all MRSA. Conclusions: Once the factors that influence the efficiency of disinfectants are controlled, sodium hypochlorite, iodophor and the quaternary ammonium compound are suitable for controlling MRSA in the sources of infection. No resistance relationship was observed in the methicillin-resistant isolates with these substances.

A microbiological evaluation of level of disinfection for flexible cystoscopes protected by disposable endosheaths

DEFF Research Database (Denmark)

Jørgensen, Peter Hjorth; Slotsbjerg, Torsten; Westh, Henrik

2013-01-01

Flexible cystoscopy is used in urological outpatient departments for diagnostic cystoscopy of bladder cancer and requires a high-level disinfection between each patient. The purpose of this study was to make a microbiological post disinfection efficacy assessment of flexible cystoscopes (FC) using...

Chemical disinfectants can reduce potato blackleg caused by ‘Dickeya solani’

NARCIS (Netherlands)

Czajkowski, R.L.; Boer, de W.J.; Wolf, van der J.M.

2013-01-01

Treatments of tubers with chemical disinfectants (70 % ethanol, 1 % sodium hypochlorite, 2 % copper sulphate, 5 % peracetic acid, 10 % hydrogen peroxide, 1 % MennoClean (benzoic acid), 5 % trisodium phosphate and 0.2 % caffeine) were evaluated for control of blackleg caused by ‘D. solani’. All

Related regulation of quality control of industrial products

International Nuclear Information System (INIS)

1983-04-01

This book introduce related regulation of quality control of industrial products, which includes regulations of industrial products quality control, enforcement ordinance of industrial products quality control, enforcement regulation of quality control of industrial products, designated items with industrial production quality indication, industrial production quality test, and industrial production quality test organization and management tips of factory quality by grade.

Regulated production of free radicals by the mitochondrial electron transport chain: Cardiac ischemic preconditioning.

Science.gov (United States)

Matsuzaki, Satoshi; Szweda, Pamela A; Szweda, Luke I; Humphries, Kenneth M

2009-11-30

Excessive production of free radicals by mitochondria is associated with, and likely contributes to, the progression of numerous pathological conditions. Nevertheless, the production of free radicals by the mitochondria may have important biological functions under normal or stressed conditions by activating or modulating redox-sensitive cellular signaling pathways. This raises the intriguing possibility that regulated mitochondrial free radical production occurs via mechanisms that are distinct from pathologies associated with oxidative damage. Indeed, the capacity of mitochondria to produce free radicals in a limited manner may play a role in ischemic preconditioning, the phenomenon whereby short bouts of ischemia protect from subsequent prolonged ischemia and reperfusion. Ischemic preconditioning can thus serve as an important model system for defining regulatory mechanisms that allow for transient, signal-inducing, production of free radicals by mitochondria. Defining how these mechanism(s) occur will provide insight into therapeutic approaches that minimize oxidative damage without altering normal cellular redox biology. The aim of this review is to present and discuss evidence for the regulated production of superoxide by the electron transport chain within the ischemic preconditioning paradigm of redox regulation.

The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product, in drinking water treatment process and its toxicity on zebrafish.

Science.gov (United States)

Lin, Tao; Zhou, Dongju; Yu, Shilin; Chen, Wei

2016-09-01

The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product (DBP) in conventional drinking water treatment plant (C-DWTP) and advanced DWTP (ADWTP) was studied with newly maximum formation potential (MFP) process. It was demonstrated that the advanced treatment displayed greater removal efficiency towards DCAcAm formation potential (MFP) than the conventional treatment. The hydrophilic natural organic matter and natural organic matter with molecular weight 10 kDa leaded to more DCAcAm formation, and the aromatic protein was inferred as one part of DCAcAm precursor. DCAcAm was found to cause delayed development and malformation to zebrafish embryos at embryonic growth stage. Compared with heart toxicity, it caused a significant neuron toxicity. It also could cause the acute DNA damage to adult zebrafish, which should be extremely cautioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conducts of disinfection, pouring and storage of irreversible hydrocolloid impressions by undergraduate students

Directory of Open Access Journals (Sweden)

Thalisson Saymo de Oliveira SILVA

Full Text Available Abstract Introduction Obtaining dental models that accurately represent the molded oral tissue requires professional attention, especially when using irreversible hydrocolloid as a molding material. Objective To evaluate the conducts of undergraduate dental students at different internships for the disinfecting procedures, pouring, and storage of irreversible hydrocolloid impressions. Material and method This is an observational, cross-sectional and descriptive study with a census sample of 89 students enrolled in the supervised internships I, II, III and IV. Data collection was performed using a structured questionnaire containing eight questions. Data were analyzed at the 5% significance level. Result Most of the students (88.8% performed the disinfection procedure, for which the most widely used method (64.6% was the application of sodium hypochlorite 1% spray stored in a sealed container. The most common disinfection time was 10 minutes (86.1%. Students in the early internships performed better in regard to the proportion of water/plaster to be used compared with students in the final internships. At all internships, pouring and storage of the ensemble of mold and model were neglected during the setting reaction. There was a statistically significant association between the stage and the disinfection method, the ratio of water/powder and pouring of the model (p<0.05. Conclusion Students exhibited appropriate conduct of disinfection; however, they should be encouraged to use evidence-based clinical practices in order to improve the procedures of pouring and storage of irreversible hydrocolloid molds.

Emergency Disinfection of Drinking Water

Science.gov (United States)

How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

Ingested nitrate and nitrite, disinfection by-products, and pancreatic cancer risk in postmenopausal women.

Science.gov (United States)

Quist, Arbor J L; Inoue-Choi, Maki; Weyer, Peter J; Anderson, Kristin E; Cantor, Kenneth P; Krasner, Stuart; Freeman, Laura E Beane; Ward, Mary H; Jones, Rena R

2018-01-15

Nitrate and nitrite are precursors of N-nitroso compounds (NOC), probable human carcinogens that cause pancreatic tumors in animals. Disinfection by-products (DBP) exposures have also been linked with digestive system cancers, but few studies have evaluated relationships with pancreatic cancer. We investigated the association of pancreatic cancer with these drinking water contaminants and dietary nitrate/nitrite in a cohort of postmenopausal women in Iowa (1986-2011). We used historical monitoring and treatment data to estimate levels of long-term average nitrate and total trihalomethanes (TTHM; the sum of the most prevalent DBP class) and the duration exceeding one-half the maximum contaminant level (>½ MCL; 5 mg/L nitrate-nitrogen, 40 µg/L TTHM) among participants on public water supplies (PWS) >10 years. We estimated dietary nitrate and nitrite intakes using a food frequency questionnaire. We computed hazard ratios (HR) and 95% confidence intervals (CI) using Cox regression and evaluated nitrate interactions with smoking and vitamin C intake. We identified 313 cases among 34,242 women, including 152 with >10 years PWS use (N = 15,710). Multivariable models of average nitrate showed no association with pancreatic cancer (HR p95 vs . Q1  = 1.16, 95% CI: 0.51-2.64). Associations with average TTHM levels were also null (HR Q4 vs . Q1  = 0.70, 95% CI:0.42-1.18). We observed no trend with increasing years of exposure to either contaminant at levels >½ MCL. Positive associations were suggested in the highest dietary nitrite intake from processed meat (HR p95 vs . Q1  = 1.66, 95% CI 1.00-2.75;p trend  = 0.05). We found no interactions of nitrate with known modifiers of endogenous NOC formation. Our results suggest that nitrite intake from processed meat may be a risk factor for pancreatic cancer. 2017 UICC.

Effects of conventional ozonation and electro-peroxone pretreatment of surface water on disinfection by-product formation during subsequent chlorination.

Science.gov (United States)

Mao, Yuqin; Guo, Di; Yao, Weikun; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F; Komarneni, Sridhar; Yu, Gang; Wang, Yujue

2018-03-01

The electro-peroxone (E-peroxone) process is an emerging ozone-based electrochemical advanced oxidation process that combines conventional ozonation with in-situ cathodic hydrogen peroxide (H 2 O 2 ) production for oxidative water treatment. In this study, the effects of the E-peroxone pretreatment on disinfection by-product (DBP) formation from chlorination of a synthetic surface water were investigated and compared to conventional ozonation. Results show that due to the enhanced transformation of ozone (O 3 ) to hydroxyl radicals (OH) by electro-generated H 2 O 2 , the E-peroxone process considerably enhanced dissolved organic carbon (DOC) abatement and significantly reduced bromate (BrO 3 - ) formation compared to conventional ozonation. However, natural organic matter (NOM) with high UV 254 absorbance, which is the major precursors of chlorination DBPs, was less efficiently abated during the E-peroxone process than conventional ozonation. Consequently, while both conventional ozonation and the E-peroxone process substantially reduced the formation of DBPs (trihalomethanes and haloacetic acids) during post-chlorination, higher DBP concentrations were generally observed during chlorination of the E-peroxone pretreated waters than conventional ozonation treated. In addition, because of conventional ozonation or the E-peroxone treatment, DBPs formed during post-chlorination shifted to more brominated species. The overall yields of brominated DBPs exhibited strong correlations with the bromide concentrations in water. Therefore, while the E-peroxone process can effectively suppress bromide transformation to bromate, it may lead to higher formation of brominated DBPs during post-chlorination compared to conventional ozonation. These results suggest that the E-peroxone process can lead to different DBP formation and speciation during water treatment trains compared to conventional ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Do personality traits related to affect regulation predict other tobacco product use among young adult non-daily smokers?

Science.gov (United States)

Brikmanis, Kristin; Petersen, Angela; Doran, Neal

2017-12-01

Understanding factors that influence non-cigarette tobacco use is important given these products' prevalence and health risks. The goal of this study was to test the hypothesis that personality traits related to affect regulation would be associated with greater frequency of other tobacco product (OTP) use in a sample of young adult non-daily smokers. Participants (n=518, 51% male) aged 18-24 were non-daily cigarette smokers recruited from the community for a longitudinal study of tobacco use. Personality characteristics (impulsivity, anhedonia, and negative affectivity) were measured at baseline, and participants reported recent tobacco use at baseline and 3, 6, and 9months later. Assessments were conducted online or via mobile phone. Across the 4 assessments, 33-52% of participants reported recent OTP use, with frequency of use decreasing over time. Longitudinal negative binomial regression models indicated that greater sensation seeking and lack of premeditation were associated with more frequent OTP use (psnon-daily cigarette smokers with greater propensity for immediately rewarding behaviors may use OTPs more frequently. Young, non-daily cigarette smokers with high levels of sensation seeking and/or lack of premeditation may be at increased risk for harms related to OTP use and may benefit from prevention and cessation strategies that specifically address affect. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regulation of cerebrospinal fluid production by caffeine consumption

Directory of Open Access Journals (Sweden)

Yoon Sik

2009-09-01

Full Text Available Abstract Background Caffeine is the most commonly consumed psycho-stimulant in the world. The effects of caffeine on the body have been extensively studied; however, its effect on the structure of the brain has not been investigated to date. Results In the present study we found that the long-term consumption of caffeine can induce ventriculomegaly; this was observed in 40% of the study rats. In the caffeine-treated rats with ventriculomegaly, there was increased production of CSF, associated with the increased expression of Na+, K+-ATPase and increased cerebral blood flow (CBF. In contrast to the chronic effects, acute treatment with caffeine decreased the production of CSF, suggesting 'effect inversion' associated with caffeine, which was mediated by increased expression of the A1 adenosine receptor, in the choroid plexus of rats chronically treated with caffeine. The involvement of the A1 adenosine receptor in the effect inversion of caffeine was further supported by the induction of ventriculomegaly and Na+, K+-ATPase, in A1 agonist-treated rats. Conclusion The results of this study show that long-term consumption of caffeine can induce ventriculomegaly, which is mediated in part by increased production of CSF. Moreover, we also showed that adenosine receptor signaling can regulate the production of CSF by controlling the expression of Na+, K+-ATPase and CBF.

The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

Directory of Open Access Journals (Sweden)

Glòria Carrasco-Turigas

2013-01-01

Full Text Available Disinfection by-products (DBPs are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4 (chloroform (TCM, bromodichloromethane (BDCM, dibromochloromethane (DBCM, and bromoform (TBM, MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97% and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.

Nationwide Study of Humidifier Disinfectant Lung Injury in South Korea, 1994-2011. Incidence and Dose-Response Relationships.

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Paek, Domyung; Koh, Younsuck; Park, Dong-Uk; Cheong, Hae-Kwan; Do, Kyung-Hyun; Lim, Chae-Man; Hong, Soo-Jong; Kim, Yong-Hwa; Leem, Jong-Han; Chung, Kyu Hyuck; Choi, Ye-Yong; Lee, Jong-Hyeon; Lim, Sin-Ye; Chung, Eun-Hee; Cho, Young Ah; Chae, Eun Jin; Joh, Joon-Sung; Yoon, Yup; Lee, Kyu-Hong; Choi, Bo Youl; Gwack, Jin

2015-12-01

Humidifier disinfectant lung injury is an acute lung disease attributed to recurrent inhalation of certain disinfectant aerosols emitted from room humidifiers. An outbreak of this toxic lung injury occurred in South Korea from 1995 until all humidifier disinfectant products were recalled from the consumer market by the government in 2011. A nationwide study was conducted to ascertain and classify all potential cases of humidifier disinfectant lung injury in Korea and to assess dose-response relationships. By several mechanisms, clinicians and the general public were invited to report all suspected cases of humidifier disinfectant lung injury to public health officials in South Korea. A committee was convened to define diagnostic criteria based on pathologic, radiologic, and clinical findings for index cases, combined with assessment of environmental exposure to humidifier disinfectants. Clinical review and environmental assessments were performed and later combined to determine overall likelihood of disease for each study participant, classified as definite, probable, possible, or unlikely. Survival time from exposure to onset of symptoms was analyzed to assess dose-response relationships. Three broad categories of risk factors were examined: (1) biological susceptibility, (2) temporal cycle of exposure and recovery, and (3) spatial conditions and density of disinfectant. Of 374 possible cases identified and reviewed, 329 were unanimously classified by the diagnostic committee, as follows: 117 definite, 34 probable, 38 possible and 140 unlikely cases. A total of 62 individuals with definite or probable disease died. Risk factors examined for polyhexamethyleneguanidine phosphate exposure that were found to be significant in shortening survival included age 4 years or younger at onset, use of disinfectant for 7 days per week, airborne density of 800 μg/m(3) or more of disinfectant, and daily exposure 11 or more hours in duration. Dose-response analysis indicated

Quality of alcohol-based hand disinfectants and their regulatory status. Development and marketing authorisation.

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Stengele, Michael

2008-10-01

A 2005 survey showed that there are at least four legal product classifications for hand disinfectants in the European Union: medicinal products, biocidal products, cosmetics and medical devices. An internationally harmonized classification does not exist. The regulatory status of those products is defined at national level. In order to assure compliance with the regulations these four classifications provide different levels of official surveillance varying from product-specific marketing authorisations and production site audits to the obligation to just work in accordance with certain general guidelines. Biocidal product regulations cover eco-toxicological and toxicological aspects, but do not very much address to the customers' quality and efficacy expectations. In contrast, the medicinal product legislation is the most ambitious one claiming quality, safety, efficacy, and an independent benefit risk-assessment by an authority. In respect of ambition, the two remaining product categories--cosmetics and medical devices--rank between the both classifications mentioned above. For medical devices, it is the responsibility of the manufacturer to make sure the products meet defined essential requirements regarding quality, safety and performance and to have an appropriate quality assurance system implemented under third party control. For cosmetics there are some legal restrictions, but within these it is the sole responsibility of the manufacturer to ensure that the products are safe and fulfil their claims. This paper describes one way out of this increasingly complex situation, the definition of a single quality standard meeting the users' expectations as well as all legal requirements regardless of the specific sales country. This international quality standard for products would take priority over any individual national standard, to the benefit of users.

Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

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Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

2007-07-01

With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

A protocol for evaluation of the role of disinfectants in limiting pathogens and weed moulds in commercial mushroom production.

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Abosriwil, Salem O; Clancy, Kevin J

2002-03-01

In vitro and in vivo evaluations of the effects of three commercial disinfectants on isolates of Trichoderma harzianum Rifai and Cladobotryum dendroides (Bull) W Gams & Hoozemans were combined in the development of methodologies for realistic assessment of disinfectant performance. 'Environ' and 'Purogene' incorporated into agar media at 50 mg AI litre-1 were effective in totally preventing the mycelial growth of T harzianum and C dendroides isolates, whereas with 'Sudol' a concentration of 500 mg AI litre-1 was required. Evaluation of a model in vivo system was combined with observations on the fungicidal effects of disinfectants. Spore suspensions of T harzianum (Th1), T harzianum (Th2) and C dendroides prepared from culture washings with sterilised distilled water were used as contaminating inoculum. Environ, Sudol and Purogene in aqueous solutions at 1000 mg AI litre-1 were sprayed onto these building structure surfaces before or after artificial contamination with spore suspensions. Re-isolation from surfaces was carried out using agar swabs, which were prepared in visking tubing, applied to treated surfaces and incubated at 25 degrees C for 24, 48, 72 or 96 h. Environ and Purogene were more effective than Sudol in limiting the recovery of Trichoderma spp and C dendroides. All three disinfectants applied 12 h after artificial contamination onto wood, concrete or glazed surfaces were able to reduce the recovery of these isolates more effectively than when they were applied 12 h before artificial contamination. Greater persistence of contamination was noted on the rougher surfaces (wood and concrete) than on the smoother glazed surface. It was concluded in this in vivo evaluation that, in many cases, the protection achieved by the physical nature of the smooth glazed tile surfaces was equivalent to that available from the application of disinfectants, thus highlighting the attention needed to the nature of building surfaces in the structures used in the mushroom

Preliminary SEM Observations on the Surface of Elastomeric Impression Materials after Immersion or Ozone Disinfection

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Prombonas, Anthony; Yannikakis, Stavros; Karampotsos, Thanasis; Katsarou, Martha-Spyridoula; Drakoulis, Nikolaos

2016-01-01

Introduction Surface integrity of dental elastomeric impression materials that are subjected to disinfection is of major importance for the quality of the final prosthetic restorations. Aim The aim of this qualitative Scanning Electronic Microscopy (SEM) study was to reveal the effects of immersion or ozone disinfection on the surface of four dental elastomeric impression materials. Materials and Methods Four dental elastomeric impression material brands were used (two vinyl polysiloxane silicones, one polyether, and one vinyl polyether silicone). Total of 32 specimens were fabricated, eight from each impression material. Specimens were immersion (0.525% sodium hypochlorite solution or 0.3% benzalkonium chloride solution) or ozone disinfected or served as controls and examined with SEM. Results Surface degradation was observed on several speci-mens disinfected with 0.525% sodium hypochlorite solution. Similar wavy-wrinkling surface structures were observed in almost all specimens, when treated either with 0.3% benzalkonium chloride solution or ozone. Conclusion The SEM images obtained from this study revealed that both immersion disinfectants and ozone show similar impression material surface alterations. Ozone seems to be non-inferior as compared to immersion disinfectants, but superior as to environmental protection. PMID:28208993

Assessment of disinfection of hospital surfaces using different monitoring methods1

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Ferreira, Adriano Menis; de Andrade, Denise; Rigotti, Marcelo Alessandro; de Almeida, Margarete Teresa Gottardo; Guerra, Odanir Garcia; dos Santos, Aires Garcia

2015-01-01

OBJECTIVE: to assess the efficiency of cleaning/disinfection of surfaces of an Intensive Care Unit. METHOD: descriptive-exploratory study with quantitative approach conducted over the course of four weeks. Visual inspection, bioluminescence adenosine triphosphate and microbiological indicators were used to indicate cleanliness/disinfection. Five surfaces (bed rails, bedside tables, infusion pumps, nurses' counter, and medical prescription table) were assessed before and after the use of rubbing alcohol at 70% (w/v), totaling 160 samples for each method. Non-parametric tests were used considering statistically significant differences at pdisinfection process, 87.5, 79.4 and 87.5% of the surfaces were considered clean using the visual inspection, bioluminescence adenosine triphosphate and microbiological analyses, respectively. A statistically significant decrease was observed in the disapproval rates after the cleaning process considering the three assessment methods; the visual inspection was the least reliable. CONCLUSION: the cleaning/disinfection method was efficient in reducing microbial load and organic matter of surfaces, however, these findings require further study to clarify aspects related to the efficiency of friction, its frequency, and whether or not there is association with other inputs to achieve improved results of the cleaning/disinfection process. PMID:26312634

Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

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Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Ostermeyer, Christiane

2014-01-01

Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted Achromobacter species 3, when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%). Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation. Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential. PMID:24653973

Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

Directory of Open Access Journals (Sweden)

Kampf, Günter

2014-03-01

Full Text Available [english] Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted , when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%. Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation.Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential.

Evaluation of Vinegar as a Disinfectant for Extracted Human Teeth - An in-Vitro Study.

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Gogineni, Sindhuja; Ganipineni, Kiranmai; Babburi, Suresh; Venigalla, Aparna; Pinnisetti, Soujanya; Kotti, Ajay Benarji; Kalapala, Lavanya

2016-07-01

In dentistry, extracted human teeth are routinely used to learn technical and preclinical skills. Since human teeth harbour many pathogens these should be disinfected before use to minimize the risk of infections. Some commonly used disinfectants in laboratories are 10% formalin, 3% hydrogen peroxide (H2O2), 5.25% Sodium Hypochlorite (NaOCl), 70% alcohol and normal saline which have their own disadvantages like carcinogenicity, toxicity, cost effectiveness etc. Many studies have been conducted using these solutions but there is no evidence to suggest a suitable alternative for disinfecting extracted teeth. Vinegar is a sour liquid comprised mainly of acetic acid. It is cheap and commercially available shown to be effective in the prevention and control of microbial contamination. The present study was conducted for evaluation of vinegar as a disinfectant for extracted teeth. In this study a total of 40 (n=40) extracted non carious teeth were taken which were disinfected with various physical methods such as sterilization, autoclaving and chemical methods by using Vinegar, 70% Alcohol, 10% Formalin, 3% Hydrogen peroxide and 5.25% NaOCL. Later, teeth from each group were placed individually in separate test tubes containing 10ml of brain heart infusion broth at 37°C for 48 hrs to observe the evidence of growth of microorganisms. Results were analyzed using Kruskal-Wallis test. Vinegar, 10% Formalin and 3% Hydrogen peroxide were effective. The results were statistically significant with Kruskal-Wallis test value 28.053 and p-value was <0.001. Vinegar can be used as an effective disinfectant for extracted human teeth.

Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

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This letter is to brings attention several concerns that the Agency has regarding the use of sanitizer and/or disinfectant products, and other types of antimicrobial products, to treat the surfaces of heating, ventilation

Thermodynamic properties of an emerging chemical disinfectant, peracetic acid.

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Zhang, Chiqian; Brown, Pamela J B; Hu, Zhiqiang

2018-04-15

Peracetic acid (PAA or CH 3 COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH 3 COOOH (aq) , CH 3 COOOH (g) , CH 3 COOOH (l) , and CH 3 COOO (aq) - are -299.41kJ·mol -1 , -283.02kJ·mol -1 , -276.10kJ·mol -1 , and -252.60kJ·mol -1 , respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA. Copyright © 2017 Elsevier B.V. All rights reserved.

Sterilization, high-level disinfection, and environmental cleaning.

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Rutala, William A; Weber, David J

2011-03-01

Failure to perform proper disinfection and sterilization of medical devices may lead to introduction of pathogens, resulting in infection. New techniques have been developed for achieving high-level disinfection and adequate environmental cleanliness. This article examines new technologies for sterilization and high-level disinfection of critical and semicritical items, respectively, and because semicritical items carry the greatest risk of infection, the authors discuss reprocessing semicritical items such as endoscopes and automated endoscope reprocessors, endocavitary probes, prostate biopsy probes, tonometers, laryngoscopes, and infrared coagulation devices. In addition, current issues and practices associated with environmental cleaning are reviewed. Copyright © 2011. Published by Elsevier Inc.

[Water disinfection by the combined exposure to super-high frequency energy and available chlorine produced during water electrolysis].

Science.gov (United States)

Klimarev, S I; Siniak, Iu E

2014-01-01

The article reports the results of studying the effects on polluted water of SHF-energy together with the residual free (active) chlorine as a by-product of electrolysis action on dissolved chlorine-containing salts. Purpose of the studies was to evaluate input of these elements to the water disinfection effect. The synergy was found to kill microorganisms without impacts on the physicochemical properties of processed water or nutrient medium; therefore, it can be used for water treatment, and cultivation of microorganisms in microbiology.

EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS; TOPICAL

International Nuclear Information System (INIS)

Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

2001-01-01

New federal drinking water regulations have been promulgated to restrict the levels of disinfection by-products (DBPs) in finished public water supplies. DBPs are suspected carcinogens and are formed when organic material is partially oxidized by disinfectants commonly used in the water treatment industry. Additional federal mandates are expected in the near future that will also affect public water suppliers with respect to DBPs. These new federal drinking water regulations may require public water suppliers to adjust treatment practices or incorporate additional treatment operations into their existing treatment trains. Many options have been identified, including membrane processes, granular activated carbon, powered activated carbon (PAC), enhanced coagulation and/or softening, and alternative disinfectants (e.g., chlorine dioxide, ozone, and chloramines). Of the processes being considered, PAC appears to offer an attractive benefit-to-cost advantage for many water treatment plants, particularly small systems (those serving fewer than 10,000 customers). PAC has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated DBPs. Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. Activated carbons can be produced from a variety of raw materials, including wood, peat, coconut husks, and numerous types of coal. The Energy and Environmental Research Center (EERC) has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During that study, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon

Environmental methicillin-resistant Staphylococcus aureus contamination in pig herds in relation to the productive phase and application of cleaning and disinfection.

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Merialdi, G; Galletti, E; Guazzetti, S; Rosignoli, C; Alborali, G; Battisti, A; Franco, A; Bonilauri, P; Rugna, G; Martelli, P

2013-06-01

The aim of the study is to better understand MRSA environmental contamination in pig holdings in relation to the productive phase and the application of environmental cleaning and disinfection practices (C&D). This study was carried out on six herds. Dust samples from farrowing crates, weaning boxes, growing and finishing pens were collected from each herd environment prior to and after C&D and cultured for MRSA. Ten samples were collected at the end of each productive phase with the animals present and 10 additional samples were collected after C&D, prior to introduction of a new stock. The proportion of positive samples prior to C&D was lower in fattening than in other phases. The proportion of positive samples prior to and after C&D was 121/240 (50%) and 46/240 (19%) respectively. In the mixed effects logistic regression analysis it was shown not only that both productive phase and C&D were associated with the probability of having a positive sample but also that the C&D effect was different in the different productive phases. In particular the effect of C&D was stronger in farrowing crates than in the other productive phases. The results of this study show that, although current practices of cleaning and disinfection reduce MRSA environmental contamination, they are likely to be inadequate to the elimination of the microorganism. However, a strict application of hygienic protocols can lead to a marked reduction of MRSA environmental contamination. Copyright © 2012 Elsevier Ltd. All rights reserved.

Photocatalytic disinfection of surfaces with copper doped Ti02 nanotube coatings illuminated by ceiling mounted fluorescent light

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Koklic, Tilen; Pintarič, Štefan; Zdovc, Irena; Golob, Majda; Umek, Polona; Mehle, Alma; Dobeic, Martin; Štrancar, Janez

2018-01-01

High economic burden is associated with foodborne illnesses. Different disinfection methods are therefore employed in food processing industry; such as use of ultraviolet light or usage of surfaces with copper-containing alloys. However, all the disinfection methods currently in use have some shortcomings. In this work we show that copper doped TiO2 nanotubes deposited on existing surfaces and illuminated with ceiling mounted fluorescent lights can retard the growth of Listeria Innocua by 80% in seven hours of exposure to the fluorescent lights at different places in a food processing plant or in the laboratory conditions with daily reinocuation and washing. The disinfection properties of the surfaces seem to depend mainly on the temperature difference of the surface and the dew point, where for the maximum effectiveness the difference should be about 3 degrees celsius. The TiO2 nanotubes have a potential to be employed for an economical and continuous disinfection of surfaces. PMID:29768464

The placing of the disinfection stage in a reclamation plant to reduce haloform formation

Energy Technology Data Exchange (ETDEWEB)

Hart, O O

1979-10-01

Chlorination of water containing organic matter leads to the formation of various volatile halogenated hydrocarbons (VHH). Various process configurations of a water reclamation plant were studied to determine the best position of the primary disinfection stage in the plant to achieve the greatest possible reduction of haloform concentration in the water distribution system. The pros and cons of ozone and chlorine as disinfectants were also investigated. Experiment methodology is explained. Results indicate that breakpoint chlorination ahead of two active carbon adsorption stages is the preferred process sequence and disinfectant to assure the lowest possible VHH production in the distribution system. (3 diagrams, 1 drawing, 8 graphs, 54 references, 2 tables)

Effect of ultrasonic pretreatment on purified water disinfection

International Nuclear Information System (INIS)

Simon Andreu, P.; Lardin Mifsut, C.; Vergara Romero, L.; Polo Canas, P. M.; Perez Sanchez, P.; Rancano Perez, A.

2009-01-01

Due to the importance of a suitable water disinfection in order to insure a pollutant effect minimization against environment, this work has been carried out to determine how can affect an ultrasonic pre-treatment upon disinfection step. It has been confirmed the ultrasonic disintegration of bacterial cells in treated water and disinfectant power of treatment by itself, which is not enough to be used as a single method in water disinfection. It has also been proved that from a technical and economical point of view the combination of UV and ultrasound improves the UV treatment performance. Finally, it has been detected that an ultrasonic pre-treatment increases chlorination effectiveness, however the high cost in this combination makes it unfeasible of industrial scale. (Author) 6 refs

Effectiveness of cleaning-disinfection wipes and sprays against multidrug-resistant outbreak strains

NARCIS (Netherlands)

Kenters, N.; Huijskens, E.G.; Wit, S.C.J. de; Rosmalen, J. van; Voss, A.

2017-01-01

BACKGROUND: Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and

Association of hand and arm disinfection with asthma control in US nurses.

Science.gov (United States)

Dumas, Orianne; Varraso, Raphäelle; Boggs, Krislyn M; Descatha, Alexis; Henneberger, Paul K; Quinot, Catherine; Speizer, Frank E; Zock, Jan-Paul; Le Moual, Nicole; Camargo, Carlos A

2018-05-01

To investigate the association between occupational exposure to disinfectants/antiseptics used for hand hygiene and asthma control in nurses. In 2014, we invited female nurses with asthma drawn from the Nurses' Health Study II to complete two supplemental questionnaires on their occupation and asthma (cross-sectional study, response rate: 80%). Among 4055 nurses (mean age: 59 years) with physician-diagnosed asthma and asthma medication use in the past year, we examined asthma control, as defined by the Asthma Control Test (ACT). Nurses were asked about the daily frequency of hand hygiene tasks: 'wash/scrub hands with disinfectants/hand sanitizers' (hand hygiene) and 'wash/scrub arms with disinfecting products' (surrogate of surgical hand/arm antisepsis). Analyses were adjusted for age, race, ethnicity, smoking status and body mass index. Nurses with partly controlled asthma (ACT: 20-24, 50%) and poorly controlled asthma (ACT ≤19, 18%) were compared with nurses with controlled asthma (ACT=25, 32%). In separate models, both hand and arm hygiene were associated with poorly controlled asthma. After mutual adjustment, only arm hygiene was associated with poorly controlled asthma: OR (95% CI) for arm hygiene tasks (never to >10 times/day) and poor asthma control. Associations persisted after further adjustment for surfaces/instruments disinfection tasks. Frequency of hand/arm hygiene tasks in nurses was associated with poor asthma control. The results suggest an adverse effect of products used for surgical hand/arm antisepsis. This potential new occupational risk factor for asthma warrants further study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sanitizers and Disinfectants Guide. Revised

Science.gov (United States)

Healthy Schools Network, Inc., 2012

2012-01-01

Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic…

Effect of Different Disinfectants on Staphylococcus aureus and Candida albicans Transferred to Alginate and Polyvinylsiloxane Impression Materials

Directory of Open Access Journals (Sweden)

Fereydoun Parnia

2009-12-01

Full Text Available Background and aims. Several products have been marketed for disinfecting impression materials. The present study evaluated the effect of Deconex, Micro 10, Alprocid and Unisepta Plus sprays on Staphylococcus aureus and Candida albicans transferred to alginate and polyvinylsiloxane impression materials. Materials and methods. A total of 180 impressions of a maxillary model (90 alginate and 90 polyvinylsiloxane impressions were taken for the purpose of this in vitro study. Half of the impressions were infected with Staphylococcus aureus and the other half were infected with Candida albicans. Then the microorganisms were cultured and their counts were determined. Subsequently, the impressions were divided into groups of 15 impressions each. Each group was disinfected with Deconex, Micro10, Alprocid and Unisepta Plus according to manufacturers' instructions except for the control group. The culturing procedure was repeated after disinfection and microbial counts were determined again. Data was analyzed by ANOVA and paired-sample t-test. Results. There were statistically significant differences in the means of S. aureus and C. albicans counts before and after the use of disinfectants (P < 0.05. The use of the four disinfectants reduced S. aureus counts to zero in 80% of the cases. There were no statistically significant differences in S. aureus count reductions between the four disinfectants evaluated (P = 0.31. Micro 10 was more effective on alginate; Deconex was more efficient for polyvinylsiloxane and Alprocid had a better efficacy in both impression materials in eliminating C. albicans (P < 0.05. Conclusion. All the disinfectants evaluated have high disinfecting postentials.

Chlorine disinfection of grey water for reuse: effect of organics and particles.

Science.gov (United States)

Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

2008-01-01

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

Cleansing and Disinfection in the Food Industry

Directory of Open Access Journals (Sweden)

Ruhtan Baskaya

2009-02-01

Full Text Available In the applications of industrial hygiene, it is of utmost importance to define the potential risk factors in the business enterprise in question, to pay sufficient consideration to those factors, and to spend every effort for their checking and elimination. In that sense, cleansing and disinfection applications have a basic importance. Food hygiene covers all the efforts spent in order to ensure the proper conditions for the production of healthy food at every stage of the production process, extending from the farm to the table. Cleansing is the removal of the dirt or food leftovers found on the tools and equipment contacting food, and preventing their conversion into a convenient millieu for the reproduction of microorganisms. Cleansing is the process of removing not only the visible dirts and leftovers, but also a large part of the visible microorganisms. Disinfection is applied after cleansing; it is the process of disintegration of microorganisms which can cause contamination, or reduction of those microorganisms to minimum levels so that they can not create any harmful effects. [TAF Prev Med Bull 2009; 8(1.000: 93-106

A practical evaluation of detergent and disinfectant solutions on ...

African Journals Online (AJOL)

Student01

2012-01-06

Jan 6, 2012 ... Nine sanitation chemical solutions: benzalkonium chloride, sodium hypochlorite, nitric ... cleaning and disinfection in reducing selected bacteria levels as required by ..... bacteria targeted during disinfection are attached to a.

Epigenetic regulation of vascular NADPH oxidase expression and reactive oxygen species production by histone deacetylase-dependent mechanisms in experimental diabetes

Directory of Open Access Journals (Sweden)

Simona-Adriana Manea

2018-06-01

Full Text Available Reactive oxygen species (ROS generated by up-regulated NADPH oxidase (Nox contribute to structural-functional alterations of the vascular wall in diabetes. Epigenetic mechanisms, such as histone acetylation, emerged as important regulators of gene expression in cardiovascular disorders. Since their role in diabetes is still elusive we hypothesized that histone deacetylase (HDAC-dependent mechanisms could mediate vascular Nox overexpression in diabetic conditions. Non-diabetic and streptozotocin-induced diabetic C57BL/6J mice were randomized to receive vehicle or suberoylanilide hydroxamic acid (SAHA, a pan-HDAC inhibitor. In vitro studies were performed on a human aortic smooth muscle cell (SMC line. Aortic SMCs typically express Nox1, Nox4, and Nox5 subtypes. HDAC1 and HDAC2 proteins along with Nox1, Nox2, and Nox4 levels were found significantly elevated in the aortas of diabetic mice compared to non-diabetic animals. Treatment of diabetic mice with SAHA mitigated the aortic expression of Nox1, Nox2, and Nox4 subtypes and NADPH-stimulated ROS production. High concentrations of glucose increased HDAC1 and HDAC2 protein levels in cultured SMCs. SAHA significantly reduced the high glucose-induced Nox1/4/5 expression, ROS production, and the formation malondialdehyde-protein adducts in SMCs. Overexpression of HDAC2 up-regulated the Nox1/4/5 gene promoter activities in SMCs. Physical interactions of HDAC1/2 and p300 proteins with Nox1/4/5 promoters were detected at the sites of active transcription. High glucose induced histone H3K27 acetylation enrichment at the promoters of Nox1/4/5 genes in SMCs. The novel data of this study indicate that HDACs mediate vascular Nox up-regulation in diabetes. HDAC inhibition reduces vascular ROS production in experimental diabetes, possibly by a mechanism involving negative regulation of Nox expression. Keywords: NADPH oxidase, Epigenetics, HDAC, Histone acetylation, Diabetes

Intracellular mechanisms of solar water disinfection

Science.gov (United States)

Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

2016-12-01

Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

Development of the electrical discharge method for water disinfection

International Nuclear Information System (INIS)

Vojtenko, L.M.; Kononov, O.V.; Starchik, P.D.; Samojlenko, L.S.; Stavs'ka, S.S.

1995-01-01

Studies of processes of bacterially polluted water disinfection by the method of pulse electrical discharge in water are presented. The studies was performed to improve the disinfection technology. Main attention was concentrated to clear up effect of discharge instability on the disinfection. An influence of the shape and sizes of electrodes on repeatability of discharges was also investigated. It was found that salts solved in water greatly influence ultraviolet radiation absorption coefficients

[DESIDENT CaviCide a new disinfectant].

Science.gov (United States)

Severa, J; Klaban, V