title: Polycyclic aromatic hydrocarbon (PAH) contamination of surface sediments and oysters from the inter-tidal areas of Dar es Salaam, Tanzania.
abstract: Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low.
authors.affiliation: Department of Aquatic Environment and Conservation, University of Dar es Salaam, P.O. Box 60091, Dar es Salaam, Tanzania.
authors.forename: Lydia
authors.initials: L
authors.lastname: Gaspare
authors.forename: John F
authors.initials: JF
authors.lastname: Machiwa
authors.forename: S J M
authors.initials: SJ
authors.lastname: Mdachi
authors.forename: Georg
authors.initials: G
authors.lastname: Streck
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
mesh_terms: D000818:Animals; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D005506:Food Contamination; D005618:Fresh Water; D019015:Geologic Sediments / Q000032:analysis*; D010125:Ostreidae / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012623:Seawater; D012989:Soil Pollutants / Q000032:analysis; D013636:Tanzania; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical