Effects of drought on environmental health risk posed by groundwater contamination.

This publication presents a comparison of the content of pollutants in groundwater samples taken at 117 measurement points in four regions of Poland during a drought period and in the reference period without drought. Based on the chemical analyses of water, an assessment of the health risk resulting from the use of underground water for consumption was carried out. The study aimed to determine whether drought affects the increase in health risk exposure of the population. It was found that despite the occurrence of drought, the expected increase in the concentration of pollutants in water does not take place in all locations. This study found that in some cases the occurrence of drought did not cause an increase in the non-cancerogenic threat expressed by the hazard index. There were also no clear changes in excess lifetime cancer risk values except for selected measurement points. On the other hand, the statistical analysis of all data collected in the regions where the research was conducted showed a general trend of increasing environmental health risk caused by changes in groundwater pollution during drought.

Environmental health risk posed by contamination of the individual water wells.

This paper presents the results of analyzes of water samples taken from individual water wells intended for supplying households in non-urbanized areas with low population and infrastructure density. Relatively high concentrations of harmful pollutants were found in ground waters of the examined spots located in the suburban areas which may increase the risk of health incidents in exposed populations. Based on long-term measurements carried out in individual spots and toxicological data, the individual health risks related to carcinogenic effects in humans were assessed, resulting from direct ingestion of such water and from dermal contact. Non-carcinogenic hazard levels were determined, as well. In this work a novel approach to health risk assessment was proposed. It consists of determining the risks that range between minimum and possible maximum values. In the case of limited traceability of a pollutant the maximum and minimum risk values were derived from the limit of quantification (LOQ). Thus, for the minimum risk, zero concentration was applied, while for calculation of the maximum risk, LOQ was used as the possible highest pollutant content in water. The calculations proved that using untreated water for consumption and bathing is likely to cause an increase of both mutagenic and toxic risk in humans concerned. Depending on the site, the calculated non-carcinogenic hazard level expressed by the hazard index HI ranges between 0.6 and 3.6 while the excess lifetime cancer risk ELCR is of the order of 10-4.