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 sedim ents at 66 stations in 10 water quality zones in Hong Kong were collat ed and analysed. Statistical analyses indicate that, during 1995 and 1 996, the total PCBs and total PAHs were widely distributed in Hong Kon g sediments at background concentrations of 5 to 9.8 mu g kg(-1) and 4 0 to 60 mu g kg(-1) wet weight respectively. Elevated levels of total PCBs (up Is 25.5 mu g kg(-1) wet weight) and total PAHs (up to 116 mu g kg(-1) wet weight) were detected in Victoria Harbour and several oth er areas. Substantial contamination was found in typhoon shelters (tot al PCBs, up to 169 mu g kg(-1) met weight; total PAHs, up to 1159 mu g kg(-1) wet weight). Analysis of the data from the 1987 to 1996 time p eriod indicated that total PAHs were declining in most areas, with the estimated half-lives ranging from 2.9 to 10.2 yr. (C) 1998 Elsevier S cience Ltd. All rights reserved.