Accuracy of determination of total mercury in river waters: Analytical Quality Control in the Harmonised Monitoring Scheme

Abstract

The Department of the Environment in collaboration with the Regional Water Authorities has initiated a Scheme for the Harmonised Monitoring of the Quality of Inland Fresh Waters in England and Wales. The Scottish Development Department (SDD) has introduced a similar scheme in Scotland in collaboration with the River Purification Boards. To achieve the required comparability of results from all laboratories involved, each laboratory took part in an analytical quality control (AQC) scheme; this work is co-ordinated by the Water Research Centre. The general approach adopted to AQC has been described, and this paper presents the results of tests made on the determination of total mercury in river waters. Several laboratories did not achieve the required accuracy of total error not greater than ±20% of the determined concentration or 0.10 µg l^–1(whichever was the larger for different sample concentrations).