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The purpose of this paper is to show that a number of pesticides is found in groundwater and drinking water resources and to define measures that should reduce the pesticide load in groundwater resources for drinking water in the future. Although the pesticide load that enters groundwater bodies in the Netherlands has gradually decreased over the past ten years, good drinking water quality in the future is not guaranteed. Currently, a number of pesticides ise found in groundwater abstracted for the production of drinking water, worldwide. The most frequently found compounds in the Netherlands are the herbicides BAM (2,6-dichlorobenzonitrile), bentazon and mecoprop. In shallow groundwater, the same compounds are generally found as in deeper groundwater that is abstracted for the production of drinking water, mainly bentazon and mecoprop. Additionally, DEET (N,N-Diethyl-meta-toluamide) is frequently found in shallower groundwater. In order to reduce the pesticide load in groundwater resources for drinking water in the future, 43 measures have been inventoried and ranked based on their scores for 'effectiveness' and for 'practicability'. This paper describes both the most effective measures, with high scores on practicability, and those with limitations regarding practicability. These measures are the most relevant with respect to the frequently found compounds that are still authorised, i.e., bentazon, mecoprop and DEET and, to a lesser extent, glyphosate (due to the presence of its metabolite AMPA (aminomethylphosphonic acid) and glyphosate itself) and isoproturon. The implementation of abstraction-specific 'Drinking Water Protection Files', including the systematic collection of data about the relevant water abstraction and the sources and activities that can negatively affect water quality, is recommended., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Regularly ingesting water with elevated arsenic increases adverse health risks. Since September 2002, the NJ Private Well Testing Act (PWTA) has required testing untreated well water for arsenic during real estate transactions in 12 counties. Its implementation provides an opportunity to investigate the effects of policy intervention on well testing and treatment behavior. Here we analyze results of a survey mailed to 1943 random addresses (37% response), including responses from 502 private well households who purchased their homes prior to PWTA commencement and 168 who purchased after. We find the PWTA has significantly increased arsenic testing rates in an area where 21% of wells contain arsenic above the 5μg/L NJ drinking water standard. The PWTA has allowed identification of more wells with arsenic (20% of post-PWTA vs. 4% of pre-PWTA households) and more treatment for arsenic (19% of post-PWTA vs. 3% of pre-PWTA households). Such an Act is a partial answer to significant socioeconomic disparities in testing observed among households for whom it is not required. Additionally residents purchasing homes since 2002 are younger and disproportionately more likely to have children in their household (60% vs. 32%), a priority group given their particular vulnerability to effects of arsenic. Despite more wells tested under the PWTA, post-PWTA well owners forget or misremember arsenic test results more often, are more likely to report not knowing what kind of treatment they are using, and are not reporting better maintenance or monitoring of their treatment systems than pre-PWTA households. This suggests serious challenges to reducing arsenic exposure remain even when testing is a requirement. Furthermore, only a fraction of wells have been tested under the PWTA due to the slow pace of housing turnover. We recommend more public resources be made available to support private well testing among socially and biologically vulnerable groups., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Inactivating pathogens is essential to eradicate waterborne diseases. However, disinfection forms undesirable disinfection by-products (DBPs) in the presence of natural organic matter. Many regulations and guidelines exist to limit DBP exposure for eliminating possible health impacts such as bladder cancer, reproductive effects, and child development effects. In this paper, an index named non-compliance potential (NCP) index is proposed to evaluate regulatory violations by DBPs. The index can serve to evaluate water quality in distribution networks using the Bayesian Belief Network (BBN). BBN is a graphical model to represent contributing variables and their probabilistic relationships. Total trihalomethanes (TTHM), haloacetic acids (HAA5), and free residual chlorine (FRC) are selected as the variables to predict the NCP index. A methodology has been proposed to implement the index using either monitored data, empirical model results (e.g., multiple linear regression), and disinfectant kinetics through EPANET simulations. The index's usefulness is demonstrated through two case studies on municipal distribution systems using both full-scale monitoring and modeled data. The proposed approach can be implemented for data-sparse conditions, making it especially useful for smaller municipal drinking water systems.

Given the huge number of chemicals released into the environment and existing time and budget constraints, there is a need to prioritize chemicals for risk assessment and monitoring in the context of the European Union Water Framework Directive (EU WFD). This study is the first to assess the risk of 500 organic substances based on observations in the four European river basins of the Elbe, Scheldt, Danube and Llobregat. A decision tree is introduced that first classifies chemicals into six categories depending on the information available, which allows water managers to focus on the next steps (e.g. derivation of Environmental Quality Standards (EQS), improvement of analytical methods, etc.). The priority within each category is then evaluated based on two indicators, the Frequency of Exceedance and the Extent of Exceedance of Predicted No-Effect Concentrations (PNECs). These two indictors are based on maximum environmental concentrations (MEC), rather than the commonly used statistically based averages (Predicted Effect Concentration, PEC), and compared to the lowest acute-based (PNEC(acute)) or chronic-based thresholds (PNEC(chronic)). For 56% of the compounds, PNECs were available from existing risk assessments, and the majority of these PNECs were derived from chronic toxicity data or simulated ecosystem studies (mesocosm) with rather low assessment factors. The limitations of this concept for risk assessment purposes are discussed. For the remainder, provisional PNECs (P-PNECs) were established from read-across models for acute toxicity to the standard test organisms Daphnia magna, Pimephales promelas and Selenastrum capricornutum. On the one hand, the prioritization revealed that about three-quarter of the 44 substances with MEC/PNEC ratios above ten were pesticides. On the other hand, based on the monitoring data used in this study, no risk with regard to the water phase could be found for eight of the 41 priority substances, indicating a first success of the implementation of the WFD in the investigated river basins., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Cities of the future face challenges with respect to the quantity and quality of water resources, and multiple managerial options need to be considered in order to safeguard urban surface water quality. In a recently completed project on 'Source control options for reducing emissions of Priority Pollutants' (ScorePP), seven emission control strategies (ECSs) were developed and tested within a semi-hypothetical case city (SHCC) to evaluate their potential to reduce the emission of selected European priority hazardous substances (PHSs) to surface waters. The ECSs included (1) business-as-usual, (2) full implementation of relevant European (EU) directives, (3) ECS2 in combination with voluntary options for household, municipalities and industry, (4) ECS2 combined with industrial treatment and best available technologies (BAT), (5) ECS2 in combination with stormwater and combined sewer overflow treatment, (6) ECS2 in combination with advanced wastewater treatment, and (7) combinations of ECS3-6. The SHCC approach was chosen to facilitate transparency, to allow compensating for data gaps and to decrease the level of uncertainty in the results. The selected PHSs: cadmium (Cd), hexachlorobenzene (HCB), nonylphenol (NP) and pentabromodiphenyl ether (PBDE) differ in their uses and environmental fate and therefore accumulate in surface waters to differing extents in response to the application of alternative ECS. To achieve the required reduction in PHS levels in urban waters the full implementation of existing EU regulation is prioritised and feasible combinations of managerial and technological options (source control and treatment) can be highly relevant for mitigating releases.

Lead is the most prevalent toxicant in U. S. school drinking water. Yet for the vast majority of schools, federal regulation for testing taps and remediating contamination is voluntary. Using school case studies, this article discusses the regulatory vacuum that leaves children unprotected from potential exposure to very high lead doses through consumption of school water. Controlling lead hazards from water fountains, coolers, and other drinking water outlets in schools requires improved sampling protocols that can capture the inherent variability of lead release from plumbing and measure both the particulate and dissolved lead present in water. There is a need to reevaluate the potential public health implications of lead-contaminated drinking water in schools. Accounting for this misunderstood and largely overlooked exposure source is necessary in order to better understand and address childhood lead poisoning in the U. S.

Using the example of raw water quality this paper examines the relationship between different spatial characteristics (geographical and physical properties) of Water and Sewerage Companies (WaSCs) supply and sewage areas and response to the Water Framework Directive. Results were obtained from thematic analysis and content analysis of 14 interviews with WaSCs representatives. Principal component analysis and cluster analysis of 51 WaSCs business function characteristics was employed to derive groups of similar WaSCs. Results indicate that there is difference in how WaSCs approach raw water quality issues. It appears that small WaSCs with relatively large agricultural areas in their supply catchments are more likely to seek managerial solutions to raw water quality problems.

This article discusses the issue of lead contamination of drinking water, noting the various regulatory-driven measures that have been adopted in the U.S. since 1986 to address this public health issue. The article summarizes the literature on the dynamics of tap water lead contamination and discusses this widespread source of lead exposure in the context of the latest research evidence.

After almost 20 years of experience with implementing the Safe Drinking Water Act and eight with Amendments to the Act, the individual states within the United States have gained valuable experience while trying to reconcile the legal mandates provided by the statutes with the science underlying them. This paper presents four different topics illustrating the problems of reconciling these two issues in the regulation of toxic chemicals in drinking waters. It presents these from the perspectives of the states of Massachusetts, Rhode Island, Connecticut, and New Jersey and offers suggestions for improved program efficiency based on considerations of comparative human health risks. The approach and schedule for controlling toxic chemicals used through 1994 are first examined and a recommendation is made for more flexibility in the rate at which chemicals are regulated. Recent U.S. EPA proposals to more stringently control radon in drinking waters are presented in the context of all sources of radon exposures, illustrating the intersection of science, laws, and economic consequences of regulatory initiatives. Inhalation and dermal exposures as a result of using chemically contaminated drinking waters are then discussed with the suggestion of the possible underprotectiveness of some present standards. Finally, the difficulty faced by the states and federal government in the control of naturally occurring arsenic exposures through drinking water is also presented and an argument is made for more local flexibility in the application of health-based standards.

Luminescent bacteria (Photobacterium phosphoreum) may be used, on the one hand, for classical toxicity tests based on the inhibition of respiration or growth and, on the other hand, their luminescence itself may become the test criterion. Such a luminescence inhibition test is commonly called a luminescent bacteria test. It may be conducted with fresh bacteria or with conserved ones. The luminescence parameter is, just like the parameter oxygen consumption, a summative parameter for undisturbed metabolic processes. Dilution series are prepared to determine the concentration level at which no inhibition of the luminous intensity is detectable in comparison with reference samples. This paper highlights the necessity of standardizing the test methods (the influence of toxic substances depends on test duration and temperature) and describes the standardized procedure established by the DIN-Arbeitskreis "Leuchtbakterientest" (Working Group of the German Institute for Standardization for the luminescent bacteria test) using freeze-dried, liquid-dried, and fresh bacteria (DIN 38,412, part 34). Results of wastewater analyses are presented and the wide range of applications is described. The choice of biotests for applications under the Federal Water Resources Management Act (Wasserhaushaltsgesetz--WHG) and the Wastewater Charges Act (Abwasserabgabengesetz--AbwAG) is discussed and the reasons for the selection of the luminescent bacteria test are explained. Within the framework of a test battery of bioassays, this test shall be used according to section 7a WHG both for evaluating the technological level of wastewater treatment and for routine monitoring of wastewater discharges. In March 1992, this test (DIN 38,412, part 34, edition March 1991) became part of the general administrative regulations for wastewater (Rahmen-Abwasser-Verwaltungsvorschrift-RAV).

Toxicological data are not adequate to assess fully the health effects of many of the pesticides that currently contaminate or have the potential to contaminate groundwater. The National Academy of Sciences estimated in 1984 that data to conduct a complete health hazard assessment exist for only 10% of the pesticides currently on the market. Many pesticides have not been tested for their ability to cause cancer, genetic mutation, or birth defects. There are significant gaps in the toxicological data base for the majority of pesticides for which the Environmental Protection Agency proposed health advisories in 1987. To help assure that groundwater standards are adequately protective of human health when toxicological data are not adequate, additional uncertainty factors can be incorporated into such standards. Alternatively, standards can be set at the level of detection. This should be the approach when no data exist to assess major potential health effects. For example, the detection limit could be the standard if no adequate oncogenicity studies have been conducted. In addition, generic standards may be employed when data are inadequate to set chemical-specific standards. New York State has recently taken this innovative generic standard approach.

Comprehensive regulations are being developed to limit human exposure to contamination in drinking water by the United States Environmental Protection Agency (EPA) under the authority of the Safe Drinking Water Act (SDWA). These regulations are being developed in several phases and include synthetic organic chemicals, inorganic chemicals, microbiological contaminants and radionuclides. This paper addresses the fundamental concepts and approaches used by EPA in setting drinking water regulations and how EPA is using these concepts to revise the drinking water standard for chromium.