Polychlorinated biphenyls residues in eggs of different ages night heron breeding in Yuantouzhu, China

摘要: 61 eggs of night heron (Nycticorax nycticorax) were collected in 2000 in Yuantouzhu of Tai lake, China. The breeding birds were divided into three groups by age, namely two, three, four years. The residues of 15 polychlorinated biphenyl congeners in eggs were studied. 15 congeners were found in all egg samples, and PCB118 at the highest level, PCB87, PCB101 and PCB153 at second levels. Total residues of the 4 congeners occupied about 75%-85% of sum 15 congeners residues found in eggs. It was obviously that residues of congeners containing 5-6 chlorine atoms were more than others in eggs. Residues of PCBs in eggs increased with age of breeding birds. The total PCBs concentration in eggs of four years group were higher than that of three years group, two years group by 47.5% and 60.9% respectively. Different from the result of the similar studies in European countries, USA and Japan: the residue of PCB153 is the highest, it was found that in this study the residue of PCB118 is the highest in eggs, which is about 30% of the total PCBs residues, while the PCB153 17% only.