Mussel watch of PCBs and persistent pesticide residues in Perna viridis Linnaeus from Malaysian and Singapore waters

Mussel watch pollution monitoring programmes, performed at six predetermined stations on the Island of Penang, Malaysia, showed that levels of the pollutant pp′-DDE ranged between 3·7 and 17·4 ppb, while PCBs ranged between 99·9 and 599·9 ppb on a dry weight basis. Similar studies on samples from three stations in the Republic of Singapore varied from 7·11 to 8·12 and 139·8 to 256·4 ppb, respectively, for pp′-DDE and PCBs.The study further indicated that other organic chlorinated hydrocarbons were not detectable in this marine bivalve at either locality. Their absence in this instance could be a feature of the tropics, resulting perhaps from a high rate of degradation, purification or a geographical separation between the source of the pollution and the population investigated.