Research has shown that some polychlorinated biphenyl congeners degrade slowly in the environment
and build up in the food chain, causing a wide range of possible adverse effects to humans. In order to
ascertain the nature of the situation in Ghana, polychlorinated biphenyls congener residues in
Crassostrea tulipa (oysters) and Anadara senilis (mussels) at Narkwa, Ada and Anyanui in the coastal
region of Ghana were determined. At Narkwa, both bivalves’ species were collected; at Ada only
Anadara senilis were collected while at Anyanui, only Crassotrea tulipa were collected. The number of
each bivalve species collected from each site was 80 (n¼80), making up a total of 320 for the dry and
the wet seasons. The PCBs were extracted with (1:1) hexane-acetone mixture and analyzed with a gas
chromatogram equipped with 65
Ni electron capture detector, model CP 3800 using the mixed PCBs
standard of the ICES 7. Total PCBs in the bivalves ranged from 5.55 to 6.37 mg/kg wet weight in mussels
and 2.95–11.41 mg/kg wet weight in oysters, respectively. The composition of the PCB homologues in
the bivalves was dominated by tri-, hepta- and hexa-PCBs in descending order. Risk assessments
conducted on the samples indicated that edible bivalves from Narkwa, Ada and Anyanui in Ghana
might pose some health risk to the consumers.