Chlorination By-products In Water Research Articles

Drinking Water Disinfection by-Products and Congenital Malformations: A Nationwide Register-Based Prospective Study.

Background:Drinking water chlorination by-products have been associated with adverse reproductive outcomes, although the findings for congenital malformations are still inconclusive.Objective:We conducted a nationwide register-based prospective study to assess whether first trimester maternal exposure to the four most common trihalomethanes [total trihalomethanes (TTHM)] via municipal drinking water was associated with risk of congenital malformation among newborns.Methods:We included all births during 2005–2015 (live and stillbirths) of mothers residing in Swedish localities having inhabitants, two or fewer operating water works, and sufficient municipal TTHM monitoring data. Individual maternal first trimester exposure was obtained by linking TTHM measurements to residential information, categorized into no chlorination and , 5–15, and TTHM/L. We also made chlorination treatment-specific analyses (exclusive use of chloramine or hypochlorite). Outcomes and covariates were obtained via linkage to health care and administrative registers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression.Results:Based on 623,468 births and a prevalence of congenital malformation of cases/100 births, we observed associations between TTHM exposure in areas using chloramine and malformations of the nervous system (; 95% CI: 1.07, 3.12), urinary system (; 95% CI: 1.53, 2.78), genitals (; 95% CI: 1.38, 2.26), and limbs (; 95% CI: 1.10, 1.64), comparing the highest exposed category with the unexposed. No associations were observed in areas using exclusively hypochlorite as the primary water treatment method. By contrast, for malformations of the heart, a significant inverse association was observed only in areas using hypochlorite.Discussion:TTHM exposure was associated with the increased risk of malformations of the nervous system, urinary system, genitals, and limbs in areas exclusively using chloramine. An association between chloramine-related chlorination by-products and congenital malformations has not previously been highlighted and needs further attention. https://doi.org/10.1289/EHP9122

Associations between exposure to drinking water chlorination by-products and congenital malformations–a nation-wide register-based prospective study including 600,000 births

BACKGROUND AND AIM: Chlorination is globally used as a drinking water disinfectant, but chlorination by-products, like trihalomethanes (THM), are easily formed. There are indications that THM may increase the risk of certain adverse reproductive outcomes, although the results are inconsistent. We conducted a nation-wide register-based prospective study to assess whether gestational exposure to THM via drinking water was associated with risk of congenital malformations. METHODS: We included all births during 2005-2015 of mothers residing in Swedish localities with 10,000 inhabitants, ≤ two operating water treatment plants, adequate information on chlorination procedures and sufficient number of THM measurements from the municipal monitoring. Individual maternal exposure was obtained by linking THM measurements to residential history, and categorized into no chlorination, 5, 5-15 and 15 µg THM/L. We also stratified the analyses by chlorination procedure. Outcomes and covariates were obtained via linkage of several Swedish health and administrative registers. Odds ratios (OR) and 95% confidence interval (CI) were estimated by logistic regression. RESULTS:Based on ~600,000 births and after full multivariable adjustment, we observed indications of associations between prenatal THM exposure in areas using chloramine and malformations of the nervous system (OR 1.82, 95% CI: 1.07-3.12), urinary system (2.06: 1.53-2.78), genitals (1.77: 1.38-2.26) and limbs (1.34: 1.10-1.64), comparing the population exposed to 15 µg THM/L with the unexposed. No associations were observed in areas using hypochlorite alone. CONCLUSIONS:This is one of the largest studies assessing chlorination by-products and congenital malformations. In areas using chloramine, we observed that THM was associated with an increased the risk of malformations of the nervous system, urinary system, genitals, and limb. An association between chloramine related chlorination by-products and congenital malformations has not previously been highlighted and needs attention. KEYWORDS: Water quality, Birth outcomes

Enhanced photocatalytic reduction of trichloroacetic acid using F-TiO2 in the presence of methanol: degradation kinetics and byproducts pathway

ABSTRACTTrichloroacetic acid (TCAA) is considered as one of the major of water chlorination by-products. The present work demonstrates decomposition, mineralisation and dechlorination of TCAA by photocatalytic reduction using F doped TiO2. In this regard, the effects of various operational factors including F-TiO2 dose, the initial concentration of TCAA, photo-reaction time and solution pH were examined on the process efficiency. Based on the results, ,,,and, as the common anions in water, had no considerable impact on the TCAA degradation efficiency. Decomposition and mineralisation rate of TCAA by MeOH/UV/F-TiO2process under the optimum conditions (catalyst dosage of 0.34 g L−1, the contact time of 76 min, TCAA content of 1 mg L−1 and pH of 7.9) were found to be 97.1% and 68%, respectively. The decomposition intermediates of TCAAdetected by LC/MS and LC-MS/MStechniques were non-chlorinated compounds, mainly formic and acetic acids. It can be concluded thatMeOH/UV/F-TiO2processcan use as low energy and efficiently treatment method for the degradation of TCAA contaminated water and wastewater.

Exposure to Drinking Water Chlorination by-Products and Fetal Growth and Prematurity: A Nationwide Register-Based Prospective Study.

Background:Chlorination is globally used to produce of safe drinking water. Chlorination by-products are easily formed, and there are indications that these are associated with adverse reproductive outcomes.Objectives:We conducted a nationwide register-based prospective study to assess whether gestational exposure to the four most common chlorination by-products [total trihalomethanes (TTHMs)] via tap water was associated with risk of small for gestational age (SGA), preterm delivery, and very preterm delivery. To date, this is one of the largest studies assessing drinking water TTHM-associated adverse reproductive outcomes.Methods:We included all singleton births 2005–2015 (live and stillbirths) of mothers residing in Swedish localities having inhabitants, operating waterworks, adequate information on chlorination treatment, and a sufficient number of routine TTHM measurements in tap water. Individual maternal second and third trimester exposure was obtained by linking TTHM measurements to residential history, categorized into no chlorination, , 5–15, and TTHM/L. Outcomes and covariates were obtained via the linkage to Swedish health and administrative registers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression using inverse probability weighting. We stratified the analyses by chlorination treatment (chloramine, hypochlorite).Results:Based on approximately 500,000 births, we observed a TTHM dose-dependent association with increased risk of SGA, confined to treatment with hypochlorite, corresponding to a multivariable-adjusted (95% CI: 1.08, 1.33) comparing drinking water TTHM to the unexposed. Similar results were obtained when, instead of unexposed, the lowest exposure category ( TTHM) was used as reference. No clear associations were observed for preterm delivery and very preterm delivery.Discussion:Chlorination by-products exposure via drinking water was associated with increased risk of SGA in areas with hypochlorite treatment. https://doi.org/10.1289/EHP6012

Associations between exposure to drinking water chlorination by-products and being born small or preterm - a nation-wide register-based prospective study including 500,000 singleton births

OPS 24: Drinking water contamination and children’s health, Room 411, Floor 4, August 27, 2019, 10:30 AM - 12:00 PM Background: Chlorination is used globally for the production of clean drinking water, but by-products such as trihalomethanes (THM) are easily formed. There are indications that chlorination by-products may increase the risk of some adverse reproductive outcomes, but results are inconsistent. We conducted a nation-wide register-based prospective study to assess whether gestational exposure to THM via drinking water was associated with risk of small-for-gestational-age (SGA), preterm birth (PTB) and very preterm birth (VPTB). Methods: We included all singleton births 2005-2015 of mothers residing in Swedish localities having >10,000 inhabitants, ≤ two operating water treatment plants, adequate information on chlorination procedures and sufficient number of routine THM measurements in tap water. Individual maternal exposure was obtained by linking THM measurements to residential history, categorized into no chlorination, <5, 5-15 and >15 µg THM/L. We also stratified by chlorination procedure. Outcomes and covariates were obtained via the linkage to Swedish health and administrative registers. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression using inverse probability weighting. Results: Based on ~500,000 births and after full multivariable adjustment, we observed no clear association between THM exposure and risk of SGA based on all assessments. Stratifying by chlorination procedure revealed dose-dependent increased risk of SGA for hypochlorite (OR, 1.20; 95% CI, 1.08-1.33), comparing highest THM exposure with no chlorination, but not for monochloramine. For PTD and VPTD, we observed ORs 0.94 (95% CI, 0.88-1.00) and 0.83 (95% CI, 0.70-0.98), respectively comparing highest THM exposure with no chlorination. Conclusions: This is one of the largest studies assessing drinking water THM-associated adverse reproductive outcomes and we were able to consider time-specific windows of exposure and all relevant individual confounders. After considering the chlorination procedure we observed indications of increased risk of SGA which occurred at a lower exposure than previously observed.

Occurrence and speciation of chlorination byproducts in marine waters and sediments of a semi-enclosed bay exposed to industrial chlorinated effluents.

Chlorination of seawater is one of the most effective technologies for industrial biofouling control. However, chlorination leads to the formation of halogenated chlorination byproducts (CBPs) associated with potential risks to environmental and human health. The present study investigated the occurrence and distribution of CBPs in the Gulf of Fos, a semi-enclosed bay where chlorinated effluents of multiple industrial plants are discharged. Seawater samples (surface and bottom) were collected at 24 sampling stations, with some near industrial outlets and others dispersed throughout the bay. Sediment samples were also collected at 10 sampling stations. Physicochemical parameters including water temperature, pH, salinity, bromide content, and free and total residual oxidant were determined. Several chemical classes of CBPs including trihalomethanes, haloacetic acids, haloacetonitriles, trihaloacetaldehydes, and halophenols were analyzed. Bromoform was the most abundant CBP in seawater, and it was detected at most of the sampling stations of the bay with highest concentrations occurring near the industrial effluent outlets. Dibromoacetic acid was the second most abundant CBP at most of the sites followed by dibromoacetonitrile. Other detected CBPs included tribromoacetic acid, bromochloroacetonitrile, and bromal hydrate. To our knowledge, the concentration of the latter CBP was reported here for the first time in the context of industrial seawater chlorination. In sediments, two bromine-containing halophenols (2-chloro-4-bromophenol and 2,4,6-tribromophenol) were detected at two sampling stations. Ecotoxicological assays and risk assessment studies based on the detected environmental concentrations are warranted to elucidate the impacts of marine CBP contamination.

Comparative toxicity studies on bromochloroacetate, dibromoacetate, and bromodichloroacetate in J774A.1 macrophages: Roles of superoxide anion and protein carbonyl compounds.

The brominated and mixed bromo-chloro-haloacetates, such as dibromoacetate (DBA), bromochloroacetate (BCA), and bromodichloroacetate (BDCA), are by-products of water chlorination and are found at lower levels than the fully chlorinated acetates in the drinking water. The toxicities of the compounds were assessed in J774A.1 cells and were found to induce concentration-dependent increases in cell death and superoxide anion and protein carbonyl compounds production. Compared to the previously tested concentrations of dichoroacetate (DCA) and trichloroacetate (TCA) in the same cell line, the tested haloacetates induced similar effects on cellular viability and superoxide anion production but at DBA and BCA concentrations that were approximately 40-160 times lower than those of DCA and TCA, and at BDCA concentrations that were 4-16 times lower than those of DCA and TCA. Also, production of super oxide anion, protein carbonyl compounds, and induction of phagocytic activation are suggested to play a role in their toxicity.

Dichloroacetonitrile induces cytotoxicity through oxidative stress-mediated and p53-dependent apoptosis pathway in LO2 cells

Dichloroacetonitrile (DCAN), one of the disinfection byproducts of water chlorination, induces cell proliferation and apoptosis; however, the detailed mechanism remains unclear. Oxidative stress participates in various biological processes, including DNA damage and cytotoxicity. To explore whether oxidative stress mediated DCAN-induced cell proliferation and apoptosis, we assessed the effect of redox imbalance and apoptosis in LO2 cells. We observed increase of reactive oxygen species and malondialdehyde and increased apoptosis by 13.6% in 500 μM DCAN compared with the control group. We also observed a decrease of antioxidant ability damage including glutathione, superoxide dismutase, and total antioxidant capacity depletion. Furthermore, DCAN might activate oxidative stress-mediated apoptosis pathway via up-regulation of p53 expression and caspase-3 activity. Therefore, we conclude that DCAN may activate apoptotic signals via p53 up-regulation and oxidative stress-mediated apoptosis in LO2 cells.

Impact of UV disinfection on the potential of model organic-nitrogen precursors to form chlorination by-products in swimming pool water

The article presents the results of experiments on the potential of model solutions of urea, creatinine, glycine, histidine, and arginine to form several organic chlorination by-products. These precursors are the main organic-nitrogen compounds, whose sources in swimming pool water are sweat and urine of bathers. In the article, the formation potential of the following by-products has been presented and discussed: trichloromethane; monochloroacetic acid; dichloroacetic acid; trichloroacetic acid; trichloroacetonitrile; dichloroacetonitrile; 1,1-dichloropropanone; 1,1,1-trichloropropanone; chloral hydrate; and chloropicrin. The test on by-products formation potential was applied to conduct the experiments, and 24-h incubation time was applied for the swimming pool water samples, disinfected in three variants of treatment: (1) chlorination alone; (2) chlorination and Ultraviolet (UV) irradiation (cumulative dose 23.5 kJ/m2); and (3) chlorination and UV irradiation (cumulative dose 47 kJ/m2). The low-pressure UV lamp by Heraeus was used to irradiate the samples. The results of experiments have been discussed and analyzed to study the influence of UV radiation on the reactivity of individual model precursors and their potential to form halogenated organic chlorination by-products.

Protective effect of curcumin on chloroform as by-product of water chlorination induced cardiotoxicity

Chloroform (CHCl3) is one of the volatile organic compounds detected most frequently in both ground and surface water. This study aimed to evaluate the efficacy of curcumin (CMN) to attenuate CHCl3 toxicity and cellular dysfunction in cardiac tissue of female albino rats. Fifty rats were divided into 5 groups, 1st group was control; 2nd group rats were intoxicated with 150mg CHCl3/kg BW; 3rd group rats were treated with 50mg CMN/kg BW; 4th group rats were treated with 50mg CMN/kg BW for 30 days then intoxicated with 150mg CHCl3/kg BW for 60 days and 5th group rats were intoxicated with 150mg CHCl3/kg BW plus 50mg CMN/kg BW, respectively. Treatment was continued for 90 days. The levels of lipid peroxidation, myeloperoxidase (MPO) and xanthine oxidase (XO) were increased and the activities of antioxidant enzymes, protein content and endogenous antioxidants were decreased in cardiac tissues in rats treated with CHCl3 in comparison with control group. Serum cholesterol, triglycerides and LDL-C levels were increased while high HDL-C was decreased in rats treated with CHCl3 in comparison with control group. Treatment with CMN helps in improving the adverse effect of CHCl3 toxicity; also our histological results confirm this finding. The present study could be concluded that CMN has protective and ameliorative effects against CHCl3 induced oxidative stress.

Do antioxidant enzymes and glutathione play roles in the induction of hepatic oxidative stress in mice upon subchronic exposure to mixtures of dichloroacetate and trichloroacetate?

Dichloroacetate (DCA) and trichloroacetate (TCA) are water chlorination by-products, and their mixtures were previously found to induce additive to greater than additive effects on hepatic oxidative stress (OS) induction in mice after subchronic exposure. To investigate the roles of antioxidant enzymes and glutathione (GSH) in those effects, livers of B6C3F1 mice were treated by gavage with 7.5, 15, or 30 mg DCA/kg/day, 12.5, 25, or 50 mg TCA/kg/day, and mixtures (Mix I, Mix II, and Mix III) at DCA:TCA ratios corresponding to 7.5:12.5, 15:25, and 25:50 mg/kg/day, respectively, for 13 weeks. Livers were assayed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), as well as for GSH levels. In general, DCA suppressed SOD and GSH-Px activities and GSH levels but caused no changes in CAT activity; TCA increased SOD and CAT activities, suppressed GSH-Px activity, but did not change GSH levels; mixtures of DCA and TCA increased SOD and CAT activities and suppressed GSH-Px activity and GSH levels. In conclusion, antioxidant enzymes contribute to DCA-, TCA-, and mixtures-induced OS, but not to changes from additive to greater than additive effects produced by different mixture compositions of the compounds. GSH on the other hand may contribute to these changes.

Drinking Water Chlorination By-Products and Intra-Uterine Growth Restriction: is there an effect modification of the CYP2E1 G1259C gene polymorphism?

Background. Genetic polymorphisms could interact with disinfection by-products metabolism and increase their toxicity which may result in an increased risk of intrauterine growth restriction (IUGR). Aim. To evaluate whether the single nucleotide polymorphism (SNP) rs3813867 (G1259C) of CYP2E1 gene modifies the relationship between IUGR and trihalomethanes (THMs) exposure during pregnancy as previously reported by Infante-Rivard (2004). Methods. The design and THMs exposure of our population-based case-control study were presented recently (Levallois et al, 2012). Cases were term single neonates with birth weight &lt;10th percentile of the age- and sex-specific Canadian birth weight distribution. Three controls (birth weight &gt;10th percentile) per case were chosen among births from the same calendar week. Exposure of mothers during the last trimester of pregnancy was based on intensive monitoring of DBPs of the water distribution systems serving the residences and a phone questionnaire of mothers two months after birth. DNA samples of infants and mothers were extracted from either blood or saliva samples. SNPs were genotyped with a multiplexed PCR reaction (MassARRAY SNP Multiplex Sequenom). Non-caucasian infants were excluded from the analysis. Odds Ratios (OR) were estimated by a non-conditional logistic regression on infant and mother genotype. Risk factors for IUGR were included in the model. Results. SNP genotypes were available for 298 cases and 1182 controls and their mothers. For total THMs ? 80?g/L, the adjusted OR for children with 1 or 2 variant alleles of CYP2E1 G1259C was estimated at 3.44 (95% CI: 0.63-18.57) in comparison with 1.20 (95%CI:0.80-1.73) for the wild type group (p value for interaction=0.325). Conclusion. We did not observe any significant effect modification of the CYP2E1 G1259C SNP on the association between DBP exposure and IUGR.

Environmental Risk Assessment on Chlorination By-Products in Discharge Water from Once-Through Seawater Cooling System

Concentration analysis was performed on five chlorination by-products in discharge water from once-through seawater cooling system of Dagang Power Plant in Tianjin. In addition, toxic effects [L (E)C50] analysis was performed from three basic levels of aquatic organisms Scenedemus vacuolatus, Daphnia magna and Oncorhynchus mykiss). Based on this, the quotient method from the Technical Guidance Document (TGD) on Risk Assessment of Chemical Substances by the European Union was adopted to assess the ecological risks of five chlorination by-products in discharge water from once-through seawater cooling system. The results showed that chloral, dichloroacetic acid and pentachlorophenol had environmental risk.

Analysis of different high production volume chemicals and their chlorination by-products in waters by ultrasound-assisted emulsification–microextraction

Ultrasound-assisted emulsification–microextraction (USAEME) demonstrated its applicability for the analysis in waters of 2-phenylphenol (PP), 4-tert-butylphenol (TBP), benzothiazole (BTZ) and piperonyl butoxide (PBO), belonging to different chemical families, and all of them characterised by its high production volume. In the developed USAEME procedure, compounds were extracted in chloroform from 10 mL of water sample during only 5 min. The addition of derivatising reagents has been studied as part of the optimisation process. The optimised procedure provided an efficient and exhaustive extraction with the advantage that the extract was ready for GC analysis. The method was validated using real environmental water samples, obtaining recoveries between 68 and 111%, RSD values ≤10%, and limits of quantification at the sub-ng per millilitre level (0.004–0.072 μg L−1). The application of the method to the determination of the targets in different environmental waters showed their presence in most samples.In addition, the method allowed the study of the behaviour of the compounds in the presence of chlorine as disinfection agent, reporting for the first time that BTZ and PBO remained stable even at 4 mg L−1 of chlorine concentration, whereas the phenolic compounds (TBP and PP) required low chlorination levels to be transformed into mono- and di-chlorinated derivatives.

Chlorination by-products in tap water and semen quality in England and Wales

ObjectivesDisinfection by-products (DBPs) have been associated with adverse semen outcomes in laboratory animals, although the evidence for trihalomethanes (THMs) is limited. Three small epidemiological studies found little evidence for an...

The Induction of Phagocytic Activation by Mixtures of the Water Chlorination By‐Products, Dichloroacetate‐ and Trichloroacetate, in Mice after Subchronic Exposure

In this study, groups of B6C3F1 male mice were treated with dichloroacetate (DCA), trichloroacetate (TCA), and mixtures of the compounds (Mix I, II, and III) daily by gavage, for 13 weeks. The tested doses were 7.5, 15, and 30 mg DCA/kg/day and 12.5, 25, and 50 mg TCA/kg/day. The DCA: TCA ratios in Mix I, II, and III were 7.5:12.5, 15:25, and 30:50 mg/kg/day, respectively. Peritoneal lavage cells were collected at the end of the treatment period and assayed for the biomarkers of phagocytic activation, including superoxide anion and tumor necrosis factor-alpha production, and myeloperoxidase activity. The mixtures produced nonlinear effects on the biomarkers of phagocytic activation, with Mix I and II effects were found to be additive, but Mix III effects were found to be less than additive.

Potential protective effect of taurine against dibromoacetonitrile-induced neurotoxicity in rats

Dibromoacetonitrile (DBAN) is a disinfection by-product of water chlorination. Epidemiological studies indicate that it might present a potential hazard to human health. The present study aimed to investigate the possible neurotoxicity of DBAN in rats and possible protection by taurine. Based on initial dose–response experiment, DBAN (60mg/kg) was administrated orally for 7 days. DBAN administration significantly impaired behavior of rats. Further, DBAN produced significant decrease of monoamines, γ-aminobutyric acid (GABA), glutamate contents, acetylcholinestrase (AChE) and aspartate aminotransferase (AST) activities, in rat brain. On the other hand, a significant increase in malondialdehyde (MDA), nitric oxide (NO) contents and lactic dehydrogenase (LDH) activity was observed. Co-administration of taurine (200mg/kg, i.p.) with DBAN mitigated most tested parameters. In conclusion, the present study indicates that DBAN has the propensity to cause significant oxidative damage in rat brain. However, taurine has a promising role in attenuating the obtained hazardous effects of DBAN.

Derivation of predicted no effect concentrations (PNEC) for 2,4,6-trichlorophenol based on Chinese resident species

2,4,6-Trichlorophenol (2,4,6-TCP) is a common chemical intermediate and a by-product of water chlorination and combustion processes, and is a priority pollutant of the aquatic environment in many countries. Although information on the toxicity of 2,4,6-TCP is available, there is a lack of information on the predicted no-effect concentration (PNEC) of 2,4,6-TCP, mainly due to the shortage of chronic and site-specific toxicity data. In the present study, acute and sub-chronic toxicity of 2,4,6-TCP on six different resident Chinese aquatic species were determined. PNEC values were calculated and compared by use of two approaches: assessment factor (AF) and species sensitivity distribution (SSD). Values for acute toxicity ranged from 1.1mgL−1 (Plagiognathops microlepis) to 42mgL−1 (Corbicula fluminea) and the sub-chronic no observed effect concentrations (NOECs) ranged from 0.05mgL−1 (Mylopharyngodon piceus) to 2.0mgL−1 (C. fluminea). PNECs obtained by the assessment factor approach with acute (AF=1000, 0.001mgL−1) or chronic (AF=10, 0.005mgL−1) toxicity data were one order of magnitude less than those from SSD methods (0.057mgL−1). PNEC values calculated using SSD methods with a 50% certainty for 2,4,6-TCP was less than those obtained by use of the USEPA recommend final chronic value (FCV) method (0.097mgL−1) and the one obtained by use of the USEPA recommend acute-to-chronic (ACR) methods (0.073mgL−1). PNECs derived using AF methods were more protective and conservative than that derived using SSD methods.

Chlorination byproducts induce gender specific autistic-like behaviors in CD-1 mice

In 2000, the Agency for Toxic Substances and Disease Registry (ATSDR) released a report concerning elevated autism prevalence and the presence water chlorination byproducts in the municipal drinking water supply in Brick Township, New Jersey. The ATSDR concluded that it was unlikely that these chemicals, specifically chloroform, bromoform (Trihalomethanes; THMs) and tetrachloroethylene (Perchloroethylene; PCE) had contributed to the prevalence of autism in this community based upon correlations between timing of exposure and/or concentration of exposure. The ATSDR conclusion may have been premature, as there is no conclusive data evidencing a correlation between a particular developmental time point that would render an individual most susceptible to toxicological insult with the development of autism. Therefore, it was our aim to determine if these chemicals could contribute to autistic like behaviors. We found that males treated with THMs and PCE have a significant reduction in the number of ultrasonic vocalizations (USVs) emitted in response to maternal separation, which are not attributed to deficits in vocal ability to or to lesser maternal care. These same males also show significantly elevated anxiety, an increase in perseverance behavior and a significant reduction in sociability. The sum of our data suggests that male, but not female mice, develop autistic like behaviors after gestational and postnatal exposure to the aforementioned chemical triad via drinking water. We believe development of such aberrant behaviors likely involves GABAergic system development.

Reduction of chlorination byproducts in surface water using ceramic nanofiltration membranes

In this study, two ceramic nanofiltration membranes with a molecular weight cutoff of 450 Da (NF450) and 1000 Da (NF1000) were used to reduce the concentration of organic matter (OM) in natural water, and the effect on the formation of disinfection by-products (DBPs) was evaluated. The effects of pressure, conductivity and pH were studied. The formation of trihalomethanes, haloacetic acids, haloacetonitriles and haloketones was evaluated. The results of the study indicated that the permeation flow rate of NF1000 was greater than that of NF450. An increase in the operating pressure improved the efficiency of OM removal and reduced the formation of DPBs. Over 75% of the formation potential of trihalomethanes was eliminated using NF450 membrane. The NF1000 membrane produces smaller decreases in trihalomethanes. As the conductivity increased from 900 μS/cm to 4000 μS/cm, the reduction of trihalomethanes decreased from 51% to 22% and from 80% to 39% for NF1000 and NF450 respectively. The flow through NF450 and NF1000 decreased when the pH of the solution decreased from pH 8.3 to pH 4.5. The values of trihalomethanes rejections at pH 8.3 were 79% and 58% for NF450 and NF1000 respectively, and these values decreased to 65% and 40% at pH 4.5.