Institute of Marine Sciences

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Browsing Institute of Marine Sciences by Subject "Chemical analysis"

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    Levels and distribution polycyclic aromatic hydrocarbons (PAHs) in interstitial water, surface sediments and Oysters from the intertidal areas of Dar es Salaam, Tanzania
    (University of Dar es salaam, 2007) Gaspare, Lydia
    Interstitial water, surface sediment and oyster samples from the intertidal areas of Dar es Salaam, Tanzania were analysed to determine the level and distribution of PAHs. Samples were extracted using shaking and Accelerated Solvent Extraction methods and cleaned up using column chromatography. Samples were analysed using GC/MS. The concentration of PAHs in interstitial water ranged from 47.15 ng/1 and in sediment ranged from 56.41 ng/g dry weight (dw) to 14815.84 ng/g dw. The concentration between sediment PAHs concentration was positively correlated to sediment fine grain size of <63 um (r=0.68, n= 18, p<0.05). the concentration of PAHs in oysters ranged from 16.82 ng/g dw. Oyster samples were enriched with 2-3 ring PAHs by 40 % of total PAHs at all sampling stations except at Ocean Road which had 31.4 % 2-3 ring PAHs. The results showed that Ocean Road was highly polluted by PAHs followed by Mzinga creek. Lowest levels of PAHs were found at Kunduchi and Tegeta. Analysis of the possible sources of PAHs suggests petrogenis and pyrolyic dominated PAHs origins. It was concluded that sediment bound PAHs were not readily bioavailable to oysters and it is recommended that monitoring program be established for PAHs, so that any exceedance in concentration overenvironmental quality standards can be detected and appropriate actions be taken.