Organochlorine Pesticides (OCPs) and Polycyclic Aromatic Hydrocarbons (PAHs) in Marine Sediments and Worms from Coastal Area of Zanzibar Town

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The State University of Zanzibar (SUZA)
The State University of Zanzibar (SUZA)



Available in print form, Tunguu Reference Library
Marine sediments and Capitella capitata worms collected from coastal area of Zanzibar Town were analysed using GC-MS to assess status of POP pollution and uptake of pollutants up the food chain. The analysis revealed the presence of organochlorine compounds (OCs) comprised of DDTs, cyclodienes and HCHs; and polycyclic aromatic hydrocarbons (PAHs) including low molecular mass (LMPAHs) and high molecular mass (HMPAHs). The concentration ranges of OCs were 0.14–102.71 and 8.51–84.53 ng/g in sediments and worms, respectively; while ranges of PAHs were ND -27.47 ng/g in sediments and ND - 17.57 ng/g in worms. The spatial distribution showed that Malindi was the most contaminated site with respect to determined pollutants in sediments and worms.The relative composition of the OCs indicated recent use of lindane and aged residues of DDT and technical HCH. Predominance of p,p’-DDE over p,p’-DDD confirms that aerobic degradation of the parent DDT was the major degradation pathway. The proportion of LMPAHs in total PAHs was relatively higher than HMPAHs, suggesting that petrogenic sources had a major contribution to the identified PAHs. The results demonstrated bioavailability and uptake of both OCs and PAHs residues by C. capitata worms, although their bio-concentration factors were very low likely due to their high ability to bio-transform the pollutants. There was relatively higher proportion of HMPAHs in worms than in sediment, confirms their high ability to bio-accumulate compared to LMPAHs. The levels of measured pollutants in sediments were several orders of magnitude lower than those measured in sediments elsewhere. The levels are also far below many sediment quality criteria such that possibility of posing adverse effect is very low.


1. Organochlorine Pesticides (OCPs) in Marine sediment and worms - Zanzibar 2. Polycyclic Aromatic Hydrocarbons (PAHs) in Marine sediment and worms - Zanzibar