Poster #2

Abstract

Arsenic is, according to WHO, one of the 10 chemicals/elements of major public health concern as it has well-known carcinogenic effects and as mg l^-1 levels may have adverse effects on public health. Drinking water in Denmark is solely of groundwater origin which generally is considered of high quality with low arsenic levels. Danish drinking water quality is routinely monitored and all analyses are added to a public geological and hydrological database, denoted Jupiter.

Here we present a national-scale overview on natural-occurring arsenic concentrations in ground- and drinking water for the last decade. More specifically our goals are: 1) to compare the arsenic concentrations from ground- and drinking water, both at the consumer and at the exit of the water treatment facilities; 2) to find and describe the proportion of samples exceeding the quality criteria; and 3) to visualize the spatial variation. In order to do that, two datasets including all quality-checked water samples containing arsenic data were selected for the period 2001-2013, consisting of respectively groundwater samples (n=29676) and drinking water samples (n=16498).

Our data analysis revealed geographical patterns with naturally occurring arsenic-rich groundwater with the highest density in the eastern part of the country. Table 1 presents a summary with the drinking water samples exceeding the criteria (1.89%); for the last decade only a small fraction of the Danish waterworks have distributed water with elevated arsenic levels to consumers.

In addition, analyses on the spatial distribution of groundwater arsenic levels with respect to the redox water type, depth of extraction, and type of predominant sediment will be presented and discussed in relation to both aqueous chemistry and public health.