Precision of benzo(a)pyrene (BaP) analysis in mussel tissue

The precision of sampling and analytical methods used to determine benzo(a)pyrene (BaP) concentrations in mussel tissue were tested. BaP concentrations in the whole tissue of 10 wild mussels, randomly collected from eight different sites along the Liguria coast, were measured two or three times. The mean coefficients of variation land standard deviation (S.D,)) were 11.5 +/- 2.4 in low contaminated samples (BaP < 2 ng/g) and 10 +/- 1.6 in mussel samples with a higher BaP concentration. The same analyses carried out in four sub-samples of breeding mussels (10 mussels each), caged for 20 days in differently polluted seawaters, showed a mean coefficients of variation (CV) of 19.5 +/- 2.4 in mussels from a clean site and of 12.2 +/- 1.1 in mussels from a contaminated site. According to the evaluated precisions, the sampling and analytical method adopted in this study can define statistically different BaP concentrations detected in the tissues of mussels collected from two sites when their difference is greater than 27%, (C) 2000 Elsevier Science Ltd. All rights reserved.