ABSTRACT
Worldwide exposure to naturally occurring arsenic in drinking water has received much attention due to adverse irreversible effects on human health. In 1993, the WHO suggested a provisional arsenic guideline value of 10 µg/L, but added that ”every effort should be made to keep concentrations as low as reasonably possible”, as the mechanism by which arsenic causes cancer remains to be determined. Until 2003, Denmark had a 50 µg/L guideline value in drinking water which then de facto was lowered to 5 µg As/L for all public waterworks. In this paper, we show changes in As concentrations at the Danish waterworks violating the new guideline and, based on this, discuss the compliance at the waterworks including technical possibilities and leaders and laggards motivations. The possibilities for lowering the guideline even below 5 µg/L in high-income, low-dose countries are also discussed.
