Great tit (Parus major) nestlings as biomonitors of organochlorine pollution

In this study we investigated the accumulation of organochlorine compounds (HCB, 3 HCH-isomers, p,p'-DDT and its metabolites and 18 PCB congeners) in the muscle and fat tissue of nestling great tits (Parus major) from four study sites located in an area with extensive environmental contamination. The concentration of p,p'-DDT, p,p'-DDD, alpha-, beta-, gamma-HCH, and PCB congeners 128 and 149 were below the limit of detection in all muscle and fat samples. In muscle tissue the concentrations of HCB and congeners 28, 52, 101, 110, and 194 were in more than 50% of the cases below detection limit and these data were excluded from statistical analysis. SigmaPCB in muscle tissue ranged from 461 to 1060 ng/g lipid weight and in fat from 776 to 1779 ng/g lipid weight. p,p'-DDE had concentrations ranging from 106 to 205 ng/g lipid weight in muscle and from 201 to 348 ng/g lipid weight in fat. HCB concentrations were very low, ranging from ND to 7.0 ng/g lipid weight in fat. We found significant differences among study sites in the concentration of Sigma PCB and of almost all individual congeners in both muscle and fat tissue. Concentrations of p,p'-DDE in muscle and fat of great tit nestlings tended to differ among sites. Principal Component Analysis (PCA) showed that the study sites with the highest Sigma PCB level had a different PCB profile than the two other sites. Our study illustrates that insectivorous passerines with a limited home range, such as the great tit, are suitable biomonitors for terrestrial organochlorine contamination.