Toxicological risk assessment of contaminants of emerging concern (CEC) in (sources of) drinking water is required to identify potential health risks and prioritize chemicals for abatement or monitoring. In such assessments, concentrations of chemicals in drinking water or sources are compared to either (i) health-based (statutory) drinking water guideline values, (ii) provisional guideline values based on recent toxicity data in absence of drinking water guidelines, or (iii) generic drinking water target values in absence of toxicity data. Here, we performed a toxicological risk assessment for 163 CEC that were selected as relevant for drinking water. This relevance was based on their presence in drinking water and/or groundwater and surface water sources in downstream parts of the Rhine and Meuse, in combination with concentration levels and physicochemical properties. Statutory and provisional drinking water guideline values could be derived from publically available toxicological information for 142 of the CEC. Based on measured concentrations it was concluded that the majority of substances do not occur in concentrations which individually pose an appreciable human health risk. A health concern could however not be excluded for vinylchloride, trichloroethene, bromodichloromethane, aniline, phenol, 2-chlorobenzenamine, mevinphos, 1,4-dioxane, and nitrolotriacetic acid. For part of the selected substances, toxicological risk assessment for drinking water could not be performed since either toxicity data (hazard) or drinking water concentrations (exposure) were lacking. In absence of toxicity data, the Threshold of Toxicological Concern (TTC) approach can be applied for screening level risk assessment. The toxicological information on the selected substances was used to evaluate whether drinking water target values based on existing TTC levels are sufficiently protective for drinking water relevant CEC. Generic drinking water target levels of 37 μg/L for Cramer class I substances and 4 μg/L for Cramer class III substances in drinking water were derived based on these CEC. These levels are in line with previously reported generic drinking water target levels based on original TTC values and are shown to be protective for health effects of the majority of contaminants of emerging concern evaluated in the present study. Since the human health impact of many chemicals appearing in the water cycle has been studied insufficiently, generic drinking water target levels are useful for early warning and prioritization of CEC with unknown toxicity in drinking water and its sources for future monitoring.

需要对饮用水（水源）中的新出现污染物（CEC）进行毒理学风险评估，以识别潜在的健康风险并确定用于减排或监测的化学品的优先级。在此类评估中，将饮用水或水源中化学物质的浓度与（i）基于健康（法定）的饮用水准则值进行比较，（ii）在没有饮用水准则的情况下根据近期毒性数据得出的临时准则值进行比较，或（ iii）没有毒性数据的一般饮用水目标值。在这里，我们对163 CEC进行了毒理学风险评估被选为与饮用水有关的食物。这种相关性是基于它们在莱茵河和默兹河下游地区的饮用水和/或地下水和地表水中的存在，以及浓度水平和理化性质。法定和临时饮用水准则值可以从142个CEC的可公开获得的毒理学信息中得出。根据测得的浓度得出的结论是，大多数物质不会以单独构成对人类健康构成明显风险的浓度存在。但是，不能排除氯乙烯，三氯乙烯，溴二氯甲烷，苯胺对健康的影响，苯酚，2-氯苯甲胺，甲氧磷，1,4-二恶烷和次氮基三乙酸。对于某些选定物质，由于缺乏毒性数据（危害）或饮用水浓度（暴露），因此无法对饮用水进行毒理学风险评估。在没有毒性数据的情况下，可以将“毒理学阈值”（TTC）方法用于筛查水平风险评估。使用所选物质的毒理学信息来评估基于现有TTC水平的饮用水目标值是否足以保护与饮用水相关的CEC。根据这些CEC，得出饮用水中Cramer I类物质的一般饮用水目标水平为37μg/ L，Cramer III类物质的目标饮用水目标水平为4μg/ L。这些水平符合先前基于原始TTC值报告的一般饮用水目标水平，并显示出对本研究中评估的大​​多数新兴污染物的健康影响的保护作用。由于尚未充分研究水循环中出现的许多化学物质对人类健康的影响，因此，一般饮用水目标水平可用于对饮用水中毒性未知的CEC进行预警和优先级划分，并将其用于未来监测。