Howard S. Weinberg

Integrated Disinfection By-Products Mixtures Research: Comprehensive Characterization of Water Concentrates Prepared from Chlorinated and Ozonated/Postchlorinated Drinking Water

This article describes the disinfection by-product (DBP) characterization portion of a series of experiments designed for comprehensive chemical and toxicological evaluation of two drinking-water concentrates containing highly complex mixtures of DBPs. This project, called the Four Lab Study, involved the participation of scientists from four laboratories and centers of the U.S. Environmental Protection Agency (EPA) Office of Research and Development, along with collaborators from the water industry and academia, and addressed toxicologic effects of complex DBP mixtures, with an emphasis on reproductive and developmental effects that are associated with DBP exposures in epidemiologic studies. Complex mixtures of DBPs from two different disinfection schemes (chlorination and ozonation/postchlorination) were concentrated successfully, while maintaining a water matrix suitable for animal studies. An array of chlorinated/brominated/iodinated DBPs was created. The DBPs were relatively stable over the course of the animal experiments, and a significant portion of the halogenated DBPs formed in the drinking water was accounted for through a comprehensive qualitative and quantitative identification approach. DBPs quantified included priority DBPs that are not regulated but have been predicted to produce adverse health effects, as well as those currently regulated in the United States and those targeted during implementation of the Information Collection Rule. New by-products were also reported for the first time. These included previously undetected and unreported bromo- and chloroacids, iodinated compounds, bromo- and iodophenols, and bromoalkyltins.

Drinking water disinfection by-product exposure and fetal growth.

Background: Previous studies suggest that elevated exposure to drinking water disinfection by-products (DBPs)—in particular, total trihalomethanes (TTHMs)—may lead to fetal growth restriction. We examined the effects of exposure to TTHMs, haloacetic acids, and total organic halide on the probability of delivering a small-for-gestational-age (SGA) infant and on birth weight at term. Methods: Women early in pregnancy (≤12 weeks’ gestation) or planning a pregnancy were enrolled in a prospective pregnancy study conducted in 3 US communities from 2000 through 2004. Weekly (or biweekly) water samples were collected at each site as well as individual-level participant data. Associations between DBP exposures (TTHMs, haloacetic acids, total organic halide) and fetal growth were assessed using log-binomial regression for SGA (n = 1958) and linear regression for term birth weight (n = 1854). We conducted a Bayesian analysis to examine associations between individual DBP species and fetal growth. Results: Haloacetic acids and total organic halide were not associated with SGA or term birth weight. The probability of delivering an SGA infant was elevated when comparing women with an average third-trimester residential TTHM concentration ≥80 &mgr;g/L to women with exposure <80 &mgr;g/L (risk ratio = 2.0 [95% confidence interval = 1.1–3.6]), but not when examining other exposure contrasts. Bayesian analyses did not support a consistent association between any DBP species and fetal growth, although these analyses were based on small sample sizes. Conclusions: Our results do not suggest an adverse effect of haloacetic acid or total organic halide exposure on fetal growth. An association of TTHM with SGA was seen only for average residential concentrations above the current regulatory standard.

Evaluation of on-site wastewater treatment technology to remove estrogens, nonylphenols, and estrogenic activity from wastewater.

A series of five on-site wastewater treatment systems were monitored for the removal of steroid estrogens, nonylphenols, and total estrogenic activity through several stages of pretreatment including aerobic and anaerobic sand filters. The objectives of this study were (1) to examine the ability of traditional septic systems and different types of pretreatment add-ons to remove nonylphenols (NPs) and the steroid estrogens estrone (E1), 17beta- estradiol (E2), estriol (E3), and 17alpha- ethinylestradiol (EE2) from the final effluent prior to discharge into the environment and (2) to examine the ability of each system and each stage of treatment within the system to remove total estrogenic activity as measured by a yeast estrogen screen (YES) assay. YES data and instrumental data are compared in the context of analyte recovery and estradiol equivalents. Results indicate excellent removal of NPs and total estrogenic activity to near or below detection limits when multiple stages of pretreatment including aerobic sand filters are used. However, only moderate removal of the steroid estrogens was observed through the anaerobic sand filters.

Meeting Report: Pharmaceuticals in Water—An Interdisciplinary Approach to a Public Health Challenge

Background The presence of pharmaceuticals in aquatic environments and in drinking water has prompted significant public interest regarding potential adverse ecological effects and risks to human health. Objectives The Environmental Health Summit held in North Carolina, 10–11 November 2008, explored the issues associated with the presence and relative risk of trace levels of pharmaceuticals in water. More than 150 participants from government organizations and institutions, academia, industry, water utilities, and public interest groups participated in discussions aimed at evaluating the current knowledge on this issue and at identifying research gaps and innovative solution-oriented recommendations. Discussion We present different aspects related to the subject that were discussed at the summit, including the source, fate, and transport of pharmaceuticals, their exposure effects and potential risks to human and ecosystems, and the best management practices to address these issues. Recommendations placed emphasis on research needs as well as education, communication, prevention, and intervention programs, and other public health solutions and actions. Conclusions Despite rising concerns about the presence of trace amounts of pharmaceuticals in drinking water, little evidence is currently available that associates these chemicals with adverse human health risks. In order to prioritize which pharmaceutical chemicals could potentially pose the highest risk to consumers and the environment, the summit participants concluded that more studies are needed to generate meaningful and accurate data.

The effect of inorganic precursors on disinfection byproduct formation during UV-chlorine/chloramine drinking water treatment

Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but remained below the World Health Organization guideline value of 70 μg/L in all cases. MP UV and high LP UV doses (1000 mJ/cm²) increased chloral hydrate formation after subsequent chlorination (20-40% increase for 40 mJ/cm² MP UV). These results indicate the importance of bench-testing DBP implications of UV applications in combination with post-disinfectants as part of the engineering assessment of a UV-chlorine/chloramine multi-barrier disinfection design for drinking water treatment.

Pre-concentration techniques for bromate analysis in ozonated waters

Abstract Ozonation of surface waters that contain bromide result in the formation of bromate which has been identified as a potential carcinogen. Regulation of bromate at the preferred concentration of less than 5 μg/1 is being delayed due to lack of a validated analytical method for quantification at this level. This paper describes the integrated use of a silver cation resin to reduce closely eluting chloride from aqueous samples followed by a chelation column to remove leached silver prior to pre-concentration of 4-ml samples on an anion-exchange column. A borate eluent used under gradient conditions allows for bromate determination at 0.5 μ/1 in treatment plant waters that, hitherto, were reported to be devoid of bromate.

Factors affecting the formation of disinfection by-products during chlorination and chloramination of secondary effluent for the production of high quality recycled water

During the production of high quality recycled water by reverse osmosis membrane filtration secondary effluent must be disinfected to limit biofouling on the membrane surface. Advanced Water Treatment Plants in South East Queensland, Australia use disinfectant contact times ranging from 30 min up to 24 h. Disinfectants such as chlorine and chloramines react with effluent organic matter to generate disinfection by-products (DBPs) which could be potentially hazardous to human health if the water is destined for supplementing public water supplies. In this context, secondary effluents are of concern because of their high total organic carbon content which can act as DBP precursors. Also, effluent organic matter may form different DBPs to those formed from natural organic matter during conventional drinking water treatment, either in quantity, identity or simply in the abundance of different DBPs relative to each other. It cannot be assumed per se with certainty that DBP formation will be affected in the same way by operational changes as in drinking water production. Response surface modelling has been employed in this study at the bench scale to investigate the effect of reaction time (0-24 h), pH (5.5-8.5), temperature (23-35 °C), disinfection strategy (chlorine vs chloramines used prior to membrane treatment) and the interaction between these different parameters on DBP formation during disinfection of secondary effluent. The concentration of halogenated DBPs formed during the first 24 h of reaction with the different disinfectants followed the order chlorination >> in line-formed monochloramine > pre-formed monochloramine. Contact time with chlorine was the major influencing factor on DBP formation during chlorination, except for the bromine-containing trihalomethanes and dibromoacetonitrile for which pH was more significant. Chlorination at high pH led to an increased formation of chloral hydrate, trichloronitromethane, dibromoacetonitrile and the four trihalomethanes while the opposite effect was observed for the other targeted DBPs. Temperature was identified as the least influencing parameter compared to pH and reaction time for all DBPs in all the disinfection strategies, except for the formation of chloral hydrate where pH and temperature had a similar significance and bromoform that was similarly affected by temperature and reaction time. Chloramines employed at pH 8.5 reduced the concentration of all studied DBPs compared to pH 5.5. Furthermore, reaction time was the most significant factor for trichloronitromethane, chloroform, trichloroacetonitrile, dichloroacetonitrile and bromochloroacetonitrile formation while pH was the most influencing factor affecting the formation of the remaining DBPs.

The healthy men study: An evaluation of exposure to disinfection by-products in tap water and sperm quality

Background Chlorination of drinking water generates disinfection by-products (DBPs), which have been shown to disrupt spermatogenesis in rodents at high doses, suggesting that DBPs could pose a reproductive risk to men. In this study we assessed DBP exposure and testicular toxicity, as evidenced by altered semen quality. Methods We conducted a cohort study to evaluate semen quality in men with well-characterized exposures to DBPs. Participants were 228 presumed fertile men with different DBP profiles. They completed a telephone interview about demographics, health history, water consumption, and other exposures and provided a semen sample. Semen outcomes included sperm concentration and morphology, as well as DNA integrity and chromatin maturity. Exposures to DBPs were evaluated by incorporating data on water consumption and bathing and showering with concentrations measured in tap water. We used multivariable linear regression to assess the relationship between exposure to DBPs and adverse sperm outcomes. Results The mean (median) sperm concentration and sperm count were 114.2 (90.5) million/mL and 362 (265) million, respectively. The mean (median) of the four trihalomethane species (THM4) exposure was 45.7 (65.3) μg/L, and the mean (median) of the nine haloacetic acid species (HAA9) exposure was 30.7 (44.2) μg/L. These sperm parameters were not associated with exposure to these classes of DBPs. For other sperm outcomes, we found no consistent pattern of increased abnormal semen quality with elevated exposure to trihalomethanes (THMs) or haloacetic acids (HAAs). The use of alternate methods for assessing exposure to DBPs and site-specific analyses did not change these results. Conclusions The results of this study do not support an association between exposure to levels of DBPs near or below regulatory limits and adverse sperm outcomes in humans.

Integrated Disinfection By-Products Mixtures Research: Disinfection of Drinking Waters by Chlorination and Ozonation/Postchlorination Treatment Scenarios

This article describes disinfection of the same source water by two commonly used disinfection treatment scenarios for purposes of subsequent concentration, chemical analysis, and toxicological evaluation. Accompanying articles in this issue of the Journal of Toxicology and Environmental Health describe concentration of these finished waters by reverse osmosis techniques, chemical characterization of the resulting disinfection by-product (DBP) concentrates, in vivo and in vitro toxicological results, and risk assessment methods developed to analyze data from this project. This project, called the “Four Lab Study,” involved participation of scientists from four laboratories/centers of the U.S. Environmental Protection Agency Office of Research and Development as well as extramural collaborators from the water industry and academia. One of the two finished waters was prepared by conventional treatment and disinfected by chlorination. The other finished water was also prepared by conventional treatment and disinfected by ozonation followed by chlorination (ozonation/postchlorination). Chlorination conditions of dose, time and temperature were similar for both treatment scenarios, allowing for a comparison. Both finished waters had acceptably low levels of particulates and bacteria, representative pH and chlorine levels, and contained numerous DBP. Known effects of ozonation were observed in that, relative to the water that was chlorinated only, the ozonated/postchlorinated water had lower concentrations of total organic halogen, trihalomethanes (THM), haloacetic acids (HAA), and higher concentrations of bromate, and aldehydes.

Drinking water disinfection by-product exposure and duration of gestation.

Background: Recent studies suggest elevated exposure to drinking water disinfection by-products (DBPs) may be associated with decreased risk of preterm birth. We examined this association for exposure to total trihalomethanes (TTHMs), 5 haloacetic acids (HAA5), and total organic halides. Methods: Analysis included 2039 women in a prospective pregnancy study conducted from 2000 through 2004 in 3 study sites. Water samples were collected and analyzed for DBP concentrations. Participant data were collected through interviews, an early ultrasound, and birth records. We assessed the associations between DBPs and preterm birth (<37-weeks’ gestation) using log-binomial regression. Discrete-time hazard analysis was used to model the conditional odds of delivery each week in relation to DBP exposure. Results: Average second trimester DBP levels were associated with lower risk of preterm birth. Adjusted risk ratios for TTHM levels of 33.1–55.0, 55.1–66.3, 66.4–74.8, and 74.9–108.8 &mgr;g/L versus 2.2–4.6 &mgr;g/L were 0.8 (95% confidence intervals = 0.5–1.3), 0.9 (0.6–1.4), 0.7 (0.4–1.1), and 0.5 (0.3–0.9), respectively. Risk ratios for HAA5 levels of 17.9–22.0, 22.1–31.5, 31.6–40.4, and 40.5–52.8 &mgr;g/L versus 0–0.9 &mgr;g/L were 1.1 (0.8–1.7), 0.8 (0.5–1.2), 0.5 (0.3–0.8), and 0.7 (0.4–1.1), respectively. The conditional odds of delivery each week were decreased for the highest TTHM and HAA5 exposure groups versus the low exposure group for gestational weeks 33–40. Conclusions: The probability of preterm birth was not increased with high DBP exposure.