Changes in the levels and profiles of persistent contaminants in nestlings of black-tailed gull (Larus crassirostris) from Hong-do, South Korea

Abstract

Birds are useful biomonitoring indicators for both the current contamination status and long-term trends in the environment. Adult bird may integrate a long-term envionmental contamination, while nestlings may represent recent and local contamination because chicks are fed with prey collected within a few kilometers of the nesting colony. To investigate the changes in the accumulation characteristics of contaminants in seagull nestling after hatching, eggs and dead nestings (ages: < one week, about three weeks, > one month) were collected from a breeding site of black-tailed gulls, Hong-do, loacted in the sourthen part of Korea. In addition, dead adult gulls were collected nearby coatal regions. The egg content and liver tissues of nestling and adult gulls were subjcted to the analyais of persistent organic pollutants including PCBs, DDTs, HCHs, chlordans,HCB, PBDEs, and HBCDs. The concentration of contaminants in nestling was highest immediately after hatching (< one week) due to maternally deposited contaminants in eggs, then rapidly declined as nestling grew (three weeks and one month of age). It is likely due to dilution of contaminant body burden through growth in size (namely, biodilution effect). Overall, isomeric (or congener) compositions were similar across all age groups with the high abundance of persistent isomer (or congener) of each compund such as PCB-153, b-HCH, DDE, PBDE-47, and a-HBCD). It is inter