Interlaboratory studies on wastewater toxicity using Daphnia magna

摘要

In order to verify the quality of biological measurements, the National Institute of Chemistry in Slovenia is regularly organizing interlaboratory comparisons to estimate the analytical precision of different laboratories using the same test and to determine if statistically significant differences exist between results. Several interlaboratory trials named “ILC-Waste Water” (ILC-WW) were organized in the last 7 years. Acute toxicity testing with Daphnia magna mobility inhibition assay (ISO 6341) was included in eight successive rounds and about 20 laboratories from Slovenia and a few adjacent countries took part in each study with two samples (T1 and T2) at two different concentration levels. Variation coefficients of the mean 24 h EC50s were determined for each exercise and the evaluation of the interlaboratory variability was analysed. Comparisons were also made of the results and the variability laboratories using organisms taken from laboratory cultures versus those who used daphnias hatched from dormant eggs (Daphtoxkits).