A survey of potential carcinogenic compounds in Danish private wells – nitrate and arsenic

Private wells for drinking water purposes in Denmark are known to contain higher levels of nitrate than drinking water from public waterworks. Only nitrate, phosphate and microbiological parameters are normally included in the... [ view full abstract ]

Private wells for drinking water purposes in Denmark are known to contain higher levels of nitrate than drinking water from public waterworks. Only nitrate, phosphate and microbiological parameters are normally included in the mandatory water quality analysis program for private wells. In addition, public waterworks are extensively registered while private wells are neither monitored nor registered sufficiently (Schullehner & Hansen, 2014). Thus, little is known about concentrations of the potential carcinogenic compounds as arsenic and nitrate in the drinking water from private wells. Accordingly, the aim of the present study is to compare concentrations of these potential carcinogenic compounds in private wells with public waterworks in the same area.

In a field campaign in 2015, we collected water samples for analysis of nitrate and arsenic from private wells in two municipalities in the western Denmark (81 nitrate & 81 arsenic analyses). Historical data from private wells were also obtained from a public-accessible database (3,953 nitrate & 11 arsenic analyses), and from the two municipalities (4,328 nitrate & 0 arsenic analyses).

As a preliminary result from the sampling campaign only one analysis had arsenic above the Danish and WHO drinking water threshold of 10 µg/L. A total of 3 samples had arsenic concentrations above 5 µg/L, which is the enforceable limit of the water leaving public Danish water works. During the conference, more results will be presented and discussed.

References:
Schullehner, J. & Hansen, B., 2014. Nitrate exposure from drinking water in Denmark over the last 35 years. Environmental Research Letters.