An assessment of the presence and health risks of endocrine-disrupting chemicals in the drinking water treatment plant of Wu Chang,China

An assessment of the presence and health risks of endocrine-disrupting chemicals in the drinking water treatment plant (DWTP) of Wu Chang was performed. A recombinant yeast assay was used to assess the endocrine disrupting activity of the effluents of the DWTP. Agonistic activities of the estrogen receptor and androgen receptor were not detected in any of the effluent samples. However, anti-estrogenic and anti-androgenic activities were observed. In addition, the removal rates of the DWTP for the anti-androgenic activities were limited. A health risk assessment was performed on the basis of the results of the recombinant yeast assay, and the total daily production of hormones was used to evaluate the health risks of these types of endocrine-disrupting chemicals. The predicted effects of the anti-estrogenic and anti-androgenic disrupting activities were below 1.5%. This study suggested that the combined toxicity bioassays with health risk assessment could provide an available method to assess endocrine-disrupting chemicals and to evaluate the potential adverse effects on human health for aquatic environmental samples.     

Risk assessment of adenoviruses detected in treated drinking water and recreational water

AIMS: Human adenoviruses (HAds) have previously been detected in sewage and polluted river and dam water, as well as treated drinking water. The 51 serotypes of HAds cause a wide range of infections with clinical manifestations associated with the gastrointestinal, respiratory and urinary tracts, and the eyes. Water may play a meaningful role in the transmission of many of these HAd serotypes, specifically the enteric HAds which are transmitted via the faecal-oral route. The presence of these viruses in water used for drinking and recreational purposes is considered to constitute a potential health risk. In this study, the risk of infection by the group of HAds previously detected over a period of 1 year in selected drinking water supplies, as well as river and dam water used for recreational purposes, was assessed. METHODS AND RESULTS: Adenoviruses were previously detected in nine of 204 (4.41%) samples of two drinking water supplies (A and B) treated and disinfected according to international specifications, in four of 51 (7.8%) samples of river water and nine of 51 (17.7%) samples of dam water. Application of these previously published results in an exponential risk assessment model indicated an annual risk of infection of 1.01 x 10(-1) and 1.7 x 10(-1) for drinking water supplies A and B, respectively, assuming a daily consumption of 2 l day(-1). The daily risk of infection constituted by HAds in the river water was calculated as 1.71 x 10(-4), and in the dam water as 3.12 x 10(-5), assuming a consumption of 30 ml of water per day. CONCLUSIONS: The risk of infection exceeded the tolerable risk of one infection per 10 000 consumers per year proposed for drinking water. However, the results for river and dam water used for recreational purposes were within the tolerable risk of one infection per 1000 bathers per day proposed for environmental waters used for recreational purposes. SIGNIFICANCE AND IMPACT OF THE STUDY: The study showed that the risk of HAd infection calculated for the drinking water supplies and the recreational water may overestimate the actual risk of infection, as conservative values were assumed for some of the variables. For a more accurate assessment of the potential risk of infection research should at least include a thorough investigation of the water consumption of individuals in South Africa, and the efficiency of recovery of the glass wool adsorption-elution method.     

Health-risk assessment related to the fluoride,nitrate, and nitrite in the drinking water in the Sanandaj,Kurdistan County,Iran

The concentration of fluoride and nitrate in groundwater is usually higher than that of surface water. The main objective of this study was to estimate the health-risk assessment associated with fluoride, nitrate, and nitrite in drinking water in Sanandaj and its villages. The number of samples in the Sanandaj and its rural was 106. The average concentration of fluoride in urban and rural drinking water was 0.22 mg/l and 0.27 mg/l, respectively. Fluoride concentration was also close to urban and rural drinking water. The concentration of nitrate in urban and rural drinking water was in the range between 0.28–27.77 mg/l and 1.28–80 mg/l, respectively. The concentration of nitrate reported in rural samples was higher than that of urban samples. The maximum concentration of nitrate reported in this study was 80 mg/l. The mean CDI for nitrate in the men, women, and children was 0.4258, 0.5110, and 1.1454, respectively. The findings of this study indicated that all three groups studied were exposed to nitrate contact hazards (HQ > 1). Therefore, the HQ in each of the three groups was higher than 1, which should be carefully monitored and necessary measures should be performed.     

Health risk assessment of fluoride in water distribution network of Mashhad,Iran

High and low levels of fluoride in drinking waters have been considered as a major public health issue in recent years. This cross-sectional study was conducted over five consecutive years (from 2012 to 2016) in the water distribution network of Mashhad city, Iran with the objectives of determining levels of fluoride and to perform health risk assessment among residents in the study area. Water samples were taken from 30 stations and were analyzed using UV-visible spectrophotometer. The mean annual concentrations of fluoride in all stations during five years of consecutive study were lower than the respective maximum permissible limits (1.5 mg/L) in water as regulated by the WHO. The human health risk assessment was performed by calculating the chronic daily intake and hazard quotient (HQ) of fluoride through human oral intake for adults (men and women) and children for each year during a five-year study. Health risk analysis in this study presented that the non-carcinogenic risk associated with fluoride exposure through drinking water in Mashhad was mostly acceptable because the mean HQ values of fluoride were lower than 1.     

Arsenic in groundwater and its health risk assessment in drinking water of Mailsi,Punjab, Pakistan

The present study was aimed at assessing drinking water quality regarding arsenic (As) and its impact on health from Mailsi (Punjab), Pakistan. Forty-four groundwater samples were collected from two sites, Sargana and Mailsi. Arsenic and other cations were determined by atomic absorption spectrophotometer, whereas the anions were determined either through titration or spectrophotometer. The results revealed that dominant anions were HCO₃^? and Cl^?, Ca⁺² was the dominant cation, and overall water chemistry of the area was CaMgHCO₃^? type. Arsenic concentrations were high, ranging from 11 to 828 µg/L that crossed the World Health Organization permissible limits. Likewise, higher SO₄^?2 concentrations ranging from 247 to 1053 mg/L were observed. The health risk index was higher in the Sargana site, which employed the differences in terms of higher Average Daily Dose, Hazard Quotient, and Carcinogenic Risk of arsenic, which is unsuitable for drinking purposes. The area seems to be at high risk due to arsenic pollution and wells have never been tested for arsenic concentrations earlier; therefore, necessary measures should be taken to test the wells with respect to arsenic.     

Mercury risks versus nutritional benefits of tribal commercial fish harvests in the Upper Laurentian Great Lakes

The Inter-Tribal Fisheries and Assessment Program (ITFAP) of the Chippewa Ottawa Resource Authority (CORA) in Sault Ste. Marie, Michigan, has been monitoring contaminant concentrations in the fillet portions of lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) from the waters of lakes Superior, Huron, and Michigan since 1991. The primary purpose of this article is to present a risk quantification of methylmercury (MeHg) that is adjusted for nutritional benefit, originally presented by Ginsberg and Toal (2009 Ginsberg GL and Toal BF. 2009. Quantitative approach for incorporating methylmercury risks and omega-3 fatty acid benefits in developing species-specific fish consumption advice. Environ Health Perspect 117:267–75[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 2015) on trends in contaminant concentrations in fillet portions of these commercial fish that we recently reported in Dellinger et al. (2014 Dellinger JA, Moths MD, Dellinger M, et al. 2014. Contaminant trends in freshwater fish from the Great Lakes: A 20 year analysis. Hum Ecol Risk Assess 20:461–78[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Both species of fish caught by tribal fishermen showed clear benefits to cardiovascular health and infant neurodevelopment if consumed at a rate of six ounces per week. However, other popularly consumed fish such as cod, tuna, and tilapia are estimated to have only marginal benefit or net negative effects on cardiovascular health and infant neurodevelopment. This dynamic assessment of benefits and risks further demonstrates the importance of traditionally caught fish in tribal health.     

Drinking water quality and arsenic health risk assessment in Sistan and Baluchestan,Southeastern Province,Iran

Access to drinking water is one of the most important indicators determined by the World Health Organization (WHO). This investigation surveyed the concentration of various pollutants in drinking water and its health risk attribute to Arsenic in Sistan and Baluchistan province, Iran. Water samples were collected from ground water and analyzed for physical parameters, anions, and heavy metals using the standard procedures. The concentrations of sulfate (269 ± 127 mg/l) in five sites exceeded the permissible limit (250 mg/l), while chlorine concentrations (223 ± 100 mg/l) in four sites exceeded the permissible limit (250 mg/l) set by WHO. Similarly, the concentrations of Mg (30 ± 11 mg/l) in four sites exceeded the permissible limit (30 mg/l), while Na concentrations (222 ± 99 mg/l) in five sites exceeded the permissible limit (200 mg/l) set by Institute of Standards and Industrial Research of Iran (ISIRI). In addition, arsenic was in acceptable levels recommended by WHO and local regulations. Based on the calculated indices of hazard qutient (HR) and excess lifetime cancer risk (ELCR), the in-use drinking water has no adverse effects on the consumer's health. Excessive use of fertilizers and pesticides, unsuitable sewerage systems, and inappropriate sludge and solid waste disposal in this province can lead to drinking water pollution. Also, excessive pumping of ground water should be managed as an effective method for supply of safe drinking water.     

Organophosphate Pesticide Residues in Drinking Water from Artesian Wells and Health Risk Assessment of Agricultural Communities,Thailand

Organophosphate pesticide (OPPs) concentrations in artesian wells located in Thai agricultural and non-agricultural communities were studied during both wet and dry seasons. A total of 100 water samples were collected and subjects were asked to complete a survey. Gas chromatography flame photometric detector was used for OPP analysis. The average OPP concentration in the agricultural communities (0.085 and 0.418 μg/l in dry and wet season) was higher than in the non-agricultural communities (0.004 μg/l in both seasons). Ingestion of OPPs in contaminated water in the agricultural communities were estimated to be 0.187 and 0.919 μg/day during the dry and wet seasons, respectively, and 0.008 μg/day during both seasons in the non-agricultural communities. Agricultural communities were exposed to pesticide residues under the oral chronic reference dose. This study suggests that people in agricultural communities may be exposed to significantly greater levels of pesticides than non-agricultural populations during the dry and wet seasons (p < .001, .001).     

Probabilistic Estimates of Lifetime Daily Doses from Consumption of Drinking Water Containing Trace Levels of N,N-diethyl-meta-toluamide (DEET), Triclosan,or Acetaminophen and the Associated Risk to Human Health

Risk assessments were conducted for N,N-diethyl-meta-toluamide (DEET), triclosan, and acetaminophen to evaluate the risk from exposure to trace levels of these chemicals through drinking water consumption. We estimated exposure to these chemicals through drinking water consumption by generating distributions for key exposure parameters using Monte Carlo analysis. Body weight and water consumption was modeled using data from the U.S. Environmental Protection Agency (USEPA) Exposure Factor Handbook. Water concentrations were derived from reported concentrations in streams. Dose-response was evaluated through extensive literature searches for toxicology data for each chemical. Acceptable daily intakes (ADIs) were then derived from the available toxicology data. The exposure distributions were compared to the ADIs to evaluate the potential risk to the population from drinking water exposure. ADIs of 0.100, 0.153, and 0.05 mg/kg-day were derived for DEET, acetaminophen and triclosan, respectively. The maximum estimated exposures (0.082, 0.834, and 0.193 μ g/kg/day for DEET, acetaminophen, and triclosan, respectively) were at least 100-fold lower than the corresponding ADIs. Based on these assessments, we conclude that there is minimal risk to human health from exposure to these chemicals at the reported concentrations in U.S. streams.     

A Probabilistic Assessment of Household Exposures to MTBE from Drinking Water

The oxygenate methyl tertiary butyl ether (MTBE) has been added to reformulated gasoline in the U.S. to meet national ambient air quality standards. Although MTBE has provided significant health benefits in terms of reduced criteria and toxic air pollutants, detections of MTBE in some groundwater and drinking water sources have raised concerns about potential environmental contamination and human exposures. In this paper, we examine the frequency and concentration of MTBE detections in drinking water sources in California from 1995 to 1999, and provide a preliminary analysis of the distribution of household exposures to MTBE from water-related activities. Using published data on the toxicity and possible cancer hazard posed by MTBE, we estimate the likely cancer and non-cancer risks for the general population in California from past and potential future MTBE exposures. More highly exposed subgroups were also addressed. Our findings indicate that less than 2% of all sampled drinking water sources in California had detectable levels of MTBE in 1999, with average MTBE drinking water concentrations ranging from 0.09 to 4.9?ppb for this year. Both the detection rate for MTBE and average MTBE concentrations have remained relatively stable since 1995, despite increased sampling of drinking water sources in California. The probabilistic exposure analysis suggests that drinking water exposures to MTBE are unlikely to pose a significant health risk for the general population or more highly exposed individuals in California.     

Influence of biofilms on iron and manganese deposition in drinking water distribution systems

Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05?mg?l^?1) and Mn (0.02?mg?l^?1) concentrations and the remaining four were exposed to a higher (0.3 and 0.4?mg?l^?1 for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0?mg?l^?1 of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (～1.5 ng cm^?2 ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall biofilms due to cell death or flow dynamics could release the entrapped Fe and Mn into the bulk water, which could lead to a discoloured water event. Hence, managing biofilm growth on drinking water pipelines should be considered by water utilities to minimize accumulation of Fe and Mn in distribution networks.     

用镶嵌组合植物群落控制湖泊饮用水源区藻类及氮污染

依据湖泊中不同生态类型水生高等植物的微生境特点,设计建造了由漂浮、浮叶、沉水植物为优势种的斑块小群丛构成的镶嵌组合水生植物群落（ＭｏｓａｉｃＣｏｍｍｕｎｉｔｙｏｆＭａｃｒｏｐｈｙｔｅｓ：ＭＣＭ）,并在太湖五里湖一湖湾内以动态模拟试验,从群落水平研究了水生高等植物群落对富营养化湖泊饮用水源区湖水的净化能力。结果表明,富营养化湖水经ＭＣＭ净化后,藻类生物量（以Ｃｈｌａ计）下降５７７％,藻类数量下降２～３个数量级,氨氮下降６６７％,总氮下降６００％,水质得到明显改善。与以该湖湾湖水为水源的水厂出水相比,经ＭＣＭ净化的湖水其氨氮比水厂出水的氨氮平均低４５１％,总氮低３７３％,可见经ＭＣＭ净化的湖水部分指标优于同源的自来水。综合群落的微生境特征及水生高等植物群落内硝化反硝化细菌分布特点,探讨了ＭＣＭ的除氮机理。     

Influence of phosphorus on biofilm formation in model drinking water distribution systems

Aims:  This study investigated the effects of phosphorus on biofilm formation via annular reactor systems in terms of biofilm cell growth, exopolysaccharide (EPS) production, biofilm structure and cell metabolic potential.
Methods and Results:  Drinking water biofilms were developed in annular reactors with supplement of carbon and different levels of phosphorus. The biofilm formation was monitored over a period of 30 days. Biofilm related parameters were examined by various methods, which included heterotrophic plate count, total carbohydrate content, confocal laser scanning microscopy and GN2 microplate assay. Our results showed that phosphorus addition can promote the biofilm cell growth (cell count increased about 1 log with addition of 30 and 300 μg l⁻¹ of phosphorus). However, the addition of 30 and 300 μg l⁻¹ of phosphorus caused 81% and 77% decrease in EPS production, respectively. The results of biofilm structure analysis showed that the addition of 30 and 300 μg l⁻¹ of phosphorus can induce thicker and less homogeneous biofilms with more biomass. Furthermore, the addition of 30 and 300 μg l⁻¹ of phosphorus dramatically increased the biofilm cell metabolic potential. The addition of 3 μg l⁻¹ of phosphorus was found to have minor effects on the parameters examined.
Conclusions:  The results indicate phosphorus addition to drinking water distribution system (DWDS) has a complicated effect on the biofilm formation.
Significance and Impact of the Study:  As the addition of phosphorus at certain levels can affect the biofilm growth in DWDS, care should be taken when phosphate-based corrosion inhibitors are used in the DWDS.     

Bio-stabilization of drinking water in supply systems as observed in the tropics

Changes in the bacterial quality of drinking water were examined in the supply system of tropical Dar es Salaam, Tanzania. The water treatment fulfilled WHO standard guidelines. However, the water quality allowed for significant regrowth of bacteria, demonstrating that the WHO guidelines are insufficient to check whether or not the drinking water has an acceptable regrowth potential. An experimental pipe system was examined on site. A growth model was established, based on a zero order bacterial detachment kinetics for the biofilms colonizing the inner surface of the pipes, with a release rate factor R, and a first order growth kinetics in the water flowing in the pipes with a growth rate factor . The rate factors were estimated to be R=1.9×10⁸ m^-2 h^-1 and =2.5 h^-1. It was concluded that growth in the biofilm played a dominant role in the bio-stabilization processes, while the initial microbial quality of the water works water and the growth in the water phase were of minor importance. The bio-stabilization process is understood herein as the reduction in the concentration of nutrients and assimilable organic carbon in the water, and thus as the reduction of the growth potential of the water. Bacterial growth and recontamination were examined during storage at the user site. The results showed that heterotrophic bacteria grew, while faecal coliforms decayed during storage. It was concluded that the users handled the water hygienically.The authors are with the Technical University of Denmark, IMT, CDC-Build, 208 DK-2800 Lyngby, Denmark     

Use of the reference dose in risk characterization of drinking water contaminants

Regulatory decisions should be made in the most expert and informed way since they are precipitated by real and perceived threats to public health, under the glare of public scrutiny. The development of environmental regulations require a three‐step paradigm, collectively called risk analysis. This paper will address the risk assessment practices required under the Safe Drinking Water Act (SDWA) Amendments of 1986 to determine a Maximum Contaminant Level Goal (MCLG, nonenforceable health goal) which should result in no known or anticipated health effects, and allows adequate margin of safety. The end product of this risk assessment, risk characterization, and risk management encompassing control options and nonrisk analysis are combined to derive the Maximum Contaminant Level (MCL, enforceable standard). Furthermore, this paper discusses the U.S. Environmental Protection Agency's efforts in exploring new and improved noncancer risk assessment approaches providing the basis for MCLGs for the protection of human health.     

Uncertainty in cancer risk at low doses of inorganic arsenic

It is unknown whether inorganic arsenic in drinking water concentrations at the current maximum contaminant level of 50 μg/1 poses a cancer risk in the United States. Data from two large epidemiological studies of cancer and arsenic in drinking water in Taiwan indicate a dose‐response relationship, but the magnitude of risk at low concentrations is highly uncertain. Four sources of uncertainty are described: model choice, data aggregation, intra‐village variability of arsenic in well water, arsenic intake from food. New data from an appropriately designed epidemiological study are needed to improve dose‐response assessment.     

Assessing Risk of Inorganic Arsenic in Drinking Water in the United States

Limitations of the current EPA risk assessment for inorganic arsenic in drinking water in the U.S. are discussed. An empirical approach is suggested that would sample survey the populations in regions with the highest arsenic levels in drinking water for signs of arsenicism, which has been much more prevalent and appeared much earlier in exposed populations than cancer (e.g., of the skin). Biomarkers of exposure, such as arsenic content in urine, nails, hair, and skin scales, may provide even earlier indications of subpopulations with excessive arsenic exposure and identify individuals at risk. Further study is needed to evaluate fully the potential for use of biomarkers, focusing on the accuracy and reliability of analytical methods, the utility of biomarkers as indicators of short-term and long-term exposure and as precursors to clinical signs of arsenicism, and the use of “normal” ranges of biomarkers for interpretation of field observations.     

桶装纯净水中三种有害元素对人体的健康风险评价

本文根据2001～2004年对桶装纯净水的监测结果,将健康风险评价的方法应用于纯净水的卫生质量评价中,根据相应的数学模型分别计算了桶装纯净水中化学致癌物As和非致癌污染物Pb、Cu通过饮用途径对人体健康的年风险。桶装纯净水中的3种有害元素由饮水途径对人体所致的健康危害程度依次是As>Pb>Cu。其中As是主要的污染,占个人年风险的99.98%。而在非致癌污染物中,Pb又是主要污染,占非致癌污染物个人年风险的82.9%。     

饮用水系统硝化微生物分布规律、环境影响因素及调控应用的研究进展

硝化微生物广泛存在于饮用水系统中。水处理过程中,硝化微生物对含氮污染物的去除有突出贡献;而输配水过程中,硝化微生物会加剧消毒剂氯胺的降解,造成一系列饮用水微生物安全问题。本文介绍了常用硝化微生物检测方法,综述了硝化微生物在滤池、市政主管网、二次供水系统中的分布特征和规律,分析了环境因子及工程条件对硝化微生物的影响机制,探讨了硝化微生物强化应用及管控的实际工程措施,展望了未来饮用水系统中硝化微生物的研究重点与应用前景。     

A quantitative risk ranking model to evaluate emerging organic contaminants in biosolid amended land and potential transport to drinking water

A quantitative risk ranking model was developed for human exposure to emerging contaminants (EC) following treated municipal sewage sludge (“biosolids”) application to Irish agricultural land. The model encompasses the predicted environmental concentration (PEC) in soil, surface runoff, groundwater, and subsequent drinking water ingestion by humans. Human exposure and subsequent risk was estimated for 16 organic contaminants using a Monte Carlo simulation approach. Nonylphenols ranked the highest across three environmental compartments: concentration in soil (PEC_soil), runoff (PEC_runoff), and groundwater (PEC_groundwater), which had mean values of 5.69 mg/kg, 1.15 × 10^?2 µg/l, and 2.22 × 10^?1 µg/l, respectively. Human health risk was estimated using the LC₅₀ (chemical intake toxicity ratio, (RR)) as a toxicity endpoint combined with PEC_runoff and PEC_groundwater. NP ranked highest for LC₅₀ combined with PEC_runoff and PEC_groundwater (mean RR values 1.10 × 10^?4 and 2.40 × 10^?3, respectively). The model highlighted triclocarban and triclosan as ECs requiring further investigation. A sensitivity analysis revealed that soil sorption coefficient and soil organic carbon were the most important parameters that affected model variance (correlation coefficient –0.89 and –0.30, respectively), highlighting the significance of contaminant and soil properties in influencing risk assessments. This model can help to prioritize emerging contaminants of concern requiring vigilance in environmental compartments.