Occurrence of Persistent Organic Contaminants and Related Substances in Hong Kong Marine Areas: an Overview

Data collected between 1987 and 1996 for PCBs and PAHs in marine sediments at 66 stations in 10 water quality zones in Hong Kong were collated and analysed. Statistical analyses indicate that, during 1995 and 1996, the total PCBs and total PAHs were widely distributed in Hong Kong sediments at background concentrations of 5 to 9.8 μg kg^-1 and 40 to 60 μg kg^-1 wet weight respectively. Elevated levels of total PCBs (up to 25.5 μg kg^-1 wet weight) and total PAHs (up to 116 μg kg^-1 wet weight) were detected in Victoria Harbour and several other areas. Substantial contamination was found in typhoon shelters (total PCBs, up to 169 μg kg^-1 wet weight; total PAHs, up to 1159 μg kg^-1 wet weight). Analysis of the data from the 1987 to 1996 time period indicated that total PAHs were declining in most areas, with the estimated half-lives ranging from 2.9 to 10.2 yr.