Copper and zinc water quality standards under the EU Water Framework Directive: The use of a tiered approach to estimate the levels of failure

• Published in: The Science of the total environment 2008-09, Vol.403 (1), p.12-22
• Main Authors: Comber, S.D.W., Merrington, G., Sturdy, L., Delbeke, K., van Assche, F.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Background concentration; Bioavailability; Biological and medical sciences; Biotic ligand model; Continental surface waters; copper; Copper - analysis; Copper - standards; data analysis; Ecotoxicology, biological effects of pollution; Environmental Monitoring - methods; environmental policy; Environmental quality standards; European Union; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects; heavy metals; meta-analysis; Metals; Natural water pollution; Pollution; Reference Standards; risk assessment; Risk Assessment - methods; Risk Assessment - standards; Tiered assessment; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - standards; water pollution; Water Pollution - prevention & control; water quality standards; Water Supply - analysis; Water Supply - standards; Water treatment and pollution; zinc; Zinc - analysis; Zinc - standards
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2008.05.017

Environmental quality standards are an important tool for assessing the chemical quality of water bodies under the Water Framework Directive. However, there must be confidence in assessments of any failure to avoid disproportionate investment in unnecessary risk reduction. Metals present a number of unique challenges for environmental regulators in that they are naturally occurring and their ecotoxicology is driven, in part, by the physico-chemical conditions of the water body in which they are present. This paper describes the use of a tiered approach that could be adopted to assess compliance with any future environmental quality standards for metals under the Water Framework Directive. Through this approach, the use of background concentrations is considered and also bioavailability via the use of biotic ligand models. This assessment is based on an analysis of routine Environment Agency chemical monitoring data combined with biological indices to support results of the approach. Using copper and zinc as examples, it is shown that it is important to take account of background concentrations and the bioavailability of metals, otherwise the risk of impact from metals may be significantly overestimated. The approach presented here provides a methodology by which regulators and the regulated community may implement surface water standards for metals under the Water Framework Directive.