| dc.description.abstract | A Study was conducted in which samples of seawater, seaweed, sediment and fish
were collected from four sites: Sabaki, Kilifi, Ramisi and Mombasa along the Kenya
coast between 1996 and 1997. The samples were: subjected to liquid extraction and
subsequent analysis of aldrin, lindane, endosulfan, dieldrin, and p,p'-DDT and its
metabolites p,p'-DDD and p,p'··DDE using gas liquid chromatography with election
capture detection. Identification was done by matching the retention times of the
analytes with those of the standard compounds. The objectives of the work were to
compare the concentrations of the chlorinated hydrocarbon insecticide residues both
within' and between sites in order to assess the contamination level of the coastal
marine environment; and to establish their variation with season of sampling.
The DDT metabolites p,p'-DDT, p,p'-DDE and p.p'-DDD (0.072-0.30 ppb), dieldrin
·(0.144-0.50 ppb), endosulfan (0.17-0.30 ppb), and aldrin (0.02-0.054 ppb) were
detected in all water samples at all sites. But p,p'-DDT and lindane were not detected
in Mombasa although they reached concentrations of 0.37 and 0.53 ppb in Kilifi,
respectively.
In Kilifi and Sabaki, lindane could not be detected in seaweed and sediment samples;
but reached concentrations of 280 and 612 ppb ill fish from Ramisi and Sabaki,
respectively. By contrast, aldrin, dieldrin, endosulfan and the p,p'-DDT metabolites
were detected in all samples at 'all-sites, at concentrations ranging from 2.35-101, 5.85-
48.5, 2.94-40.3, and 0.95-70.8 pob, respectively. Concentrations of the residues were
·consistently high in fish samples from Sabaki and generally low in those from Ramisi.
The analysis of data for seasona' effects shows that samples obtained during the wet
weather has relatively higher residue concentrations than those collected during the dry
season, and the differences are particularly significant for seaweeds and sediments.
Comparison of the concentration in ppb of organochlorine pesticides with those for
other global coastal waters shows, Cor example, that in 1995 dieldrin (1.88), endosulfan
(2.98) and p,p'-DDT (7.02) recorded ill waters from Kingston Harbour (Jamaica) were
about four, ten and twenty time) higher than the maximum range values obtained in
this study. This suggests that the coastal marine environment in Kenya is relatively
unpolluted. These data provide a baseline for future work in determining the
concentrations of chlorinated cyclic pesticides in marine samples along the coast of
Kenya. | en |
