Denmark is a staunch supporter of the precautionary EC limit of 0.1µg/l limit on pesticides in drinking water. The capital's water supply is drawn from aquifers vulnerable to pesticide pollution, so an announcement in March that tap water contained up to 0.95%g/l of a pesticide breakdown product met with high levels of public concern.
The compound involved was aminomethylphosphonic acid (AMPA), which can be formed from the breakdown of glyphosate. Glyphosate, one of the most widely used herbicides, is marketed as having low toxicity and ready biodegradability. It is approved for use close to water and for the control of aquatic weeds.
After traces of AMPA were detected by Copenhagen's water utility, the Danish Environment Protection Agency (EPA) sent water samples for blind testing to three leading laboratories. AMPA was found in both samples and blanks,and scientists eventually realised that only reused bottles were contaminated.
"It is a horrible story," an EPA spokesman told ENDS. "The chemical probably came from the detergent used to wash the sample bottles." As well as being a breakdown product of glyphosate, AMPA is formed from aminomethylphosphonates, which are commonly used as sequestering agents in detergents.