The EU Drinking Water Directive: The Boron standard and scientific uncertainty

In 1998 the European Union (EU) revised its Drinking Water Directive, which is responsible for regulating the quality of water in the EU intended for human consumption. Specifically, the EU added a new standard for the element boron in drinking water (1 mg/l). Yet, because of scientific uncertainty concerning the causes and magnitude of the boron problem in Europe during the regulatory standard-setting process, we find that full compliance with the new drinking water standard for boron has been hampered. Prior to the standard's enactment, it was unclear whether boron was derived from natural or anthropogenic sources. A new geochemical study reveals that a significant part of the boron contamination is derived from natural sources. Countries such as Italy and Cyprus with high natural boron concentrations in their drinking water are, thus, finding that compliance with the new EU boron regulation is more difficult and expensive than originally anticipated.