Publication Abstract

Analysis of BEQUALM intercalibration studies 2006

Analysis of BEQUALM intercalibration studies 2006

J. Barry and Y. Allen

The Biological Effects Quality Assurance in Monitoring Programmes (BEQUALM) was initiated to develop quality standards for a range of biological effects techniques and monitor compliance of laboratories generating data from these techniques for national and international monitoring programmes (e.g. Oslo and Paris Commission) and also for regulatory purposes. Each year, the Lead Laboratory (Cefas) organises a programme of intercalibration exercises for each of the methods included in the scheme. In this paper, the results from a 2005/6 intercalibration using a 48h acute test with Daphnia magna (water flea) are described. Each intercalibration exercise is divided into two parts. In the first, laboratories were given an unspecified concentration of a reference chemical (zinc sulphate) which they were asked to dilute by a given factor and estimate the toxicity of the substance in terms of the percentage mortality. In the second part, a pre-determined dilution series of the reference chemical was prepared by each laboratory from a provided stock and mortality at each concentration measured. From these mortalities, the medial lethal concentration (EC₅₀) was estimated for each laboratory. We describe how these results are analysed and, in particular, how compliance of laboratories is evaluated. The aim is to bring about continuous improvements in the methods adopted by the laboratories taking part.

Reference

authors (year) title, journal

J. Barry* and Y. Allen*

In: Encyclopedia of Statistics in Quality and Reliability, Wiley.