New approach methods for assessing indoor air toxicity.

Indoor air is typically a mixture of many chemicals at low concentrations without any adverse health effects alone, but in mixtures they may cause toxicity and risks to human health. The aim of this study was by using new approach methods to assess the potential toxicity of indoor air condensates. In specific, different in vitro test methods including cyto-and immunotoxicity, skin sensitization and endocrine disruption were applied. In addition to biological effects, the indoor air samples were subjected to targeted analysis of 25 volatile organic compounds (VOCs) and Genapol X-80 (a nonionic emulsifier) suspected to be present in the samples, and to a non-targeted "total chemical scan" to find out whether the chemical composition of the samples is associated with the biological effects. The results confirm that assessing health risks of indoor air by analysing individual chemicals is not an adequate approach: We were not able to detect the VOCs and Genapol X-80 in the indoor air samples, yet, several types of toxicity, namely, cytotoxicity, immunotoxicity, skin sensitization and endocrine disruption were detected. In the non-targeted total chemical scan of the indoor air samples, a larger number of compounds were found in the cytotoxic samples than in the non-cytotoxic samples supporting the biological findings. If only one biological method would be selected for the screening of indoor air quality, THP-1 macrophage/WST-1 assay would best fit for the purpose as it is sensitive and serves as a good representative for different sub-toxic end points, including immunotoxicity, (skin) sensitization and endocrine disruption.

Monitoring of pesticides in drinking water: finding the right balance between under- and over-monitoring - experience from the Czech Republic.

The modern, risk-based approach requires that only those pollutants which are likely to be present in a given water supply should be monitored in drinking water. From this perspective, defining an adequate approach to the monitoring of pesticides in areas with intensive agriculture is currently one of the greatest issues of regulation. This article shows the development and detailed results of pesticide monitoring in drinking water in the Czech Republic (CR). More than 4000 water supply zones serving around a 9.5 million population are routinely monitored, with nearly 250 thousand analyses of over 200 different pesticides and their metabolites being performed every year, with a non-compliance rate of ca. 0.3%. In 2017, pesticides accounted for most derogations in the CR, concerning a total of 64 water supply systems serving more than a 250 thousand population. A representative survey targeting 21 selected chemicals showed that 75% of water supply systems contained up to 11 pesticides per sample. The most commonly found were metabolites of the herbicides used to protect oilseed rape, maize, and sugar beet: acetochlor ESA, alachlor ESA, metazachlor OA, and chloridazon-desphenyl. The health risk assessment did not reveal any risks from these chemicals, even at the highest levels detected or in the most abundant mixtures, to the most vulnerable population (infants). Nevertheless, the increased presence of pesticides undermines the public's trust in drinking water safety.