| In this paper, the total content of heavy metals in the surface sediment and coresediment in the inter-tidal area of Quanzhou Bay was extracted and compared withthe background values in order to studying the concentration and distribution,pollution situation, history and the sources of heavy metals. The results showed theheavy metals distributed differently from each other along Luoyang Bridge toQuanzhou Bay, with the following content pattern(mg/kg): Fe（38434）> Mn（1620）> Zn（181.8）> Sr（88.57）> V（85.57）> Cr（82.15）> Pb（66.12）> Cu（59.21）> Ni（27.77）> Co（12.25）> Cd（0.620）. The content of Fe, Co, Mn and Pb weredecreased slightly along Luoyang Bridge to Quanzhou Bay. It also indicated that thecontent of most metals were high in the sampling site of L3, L18, L25, L29, L63andL64.The four forms of heavy metals (acid-soluble, reducible, oxidizable and residual) insediment were extracted by modified BCR-sequential extraction technique. Theresults showed that Cr, Ni, Zn and Fe presented comparatively higher percentages inthe residual fractions, suggesting that they were stored in the mineral crystal latticeand less harmful to the environment. Mn presented comparatively higher percentagesin the acid extractable fractions, which meaned Mn was most sensitive to the changeof environment, and easiest to release. Pb and Cu were relatively higher in thereductive fractions which showing a potential risk.The heavy metal pollution assessment in surface sediments were carried out basedon both total content and morphological analysis. The results of assessment based ontotal content showed that surface sediment was polluted seriously by Cd, Pb, Zn andCu, with the least pollution of Cr and the most pollution of Cd. The results ofassessment based on morphological analysis showed that Fe and V were atnon-pollution level while Cr, Ni, Zn and Cu presented slight pollution. The pollutionof Cd was at moderate level, but it was seriously polluted at L26and L1H samplingsites. Cu, Pb and Mn showed the highest pollution level in all sites. For each heavymetal, the results gotten from five assessment methods were consistent. The dating analysis result of the core sediment from the sampling site of L8showed that the pollution of Ni, Sr, Fe and Mn came from the natural sediment andwas polluted by Pb, Zn, V, Co, Cu, Cr, Cd, Hg, with different pollution level. It wasthe same case for the core sediment from the sampling site of L27, yet with the leastpollution of Cu. It could thus be seen that the intertidal sediment was polluted by Pb,Zn, Ni, Cu, Cr, Cd, Hg, with different pollution level.Using the Pb, Sr isotope compositions for tracing the lead pollution sources, theresults showed that the lead pollution in the intertidal zone sediments was mainlyaffected by the automobile exhaust, industrial production and sewage discharge. Theratio of206Pb/207Pb and208Pb/207Pb showed significant difference. In this way, thesources of the lead pollution in sediment could be traced. For the surface sediment,the study showed that the sediments from the33sampling points were seriouslypolluted by Pb which originated mainly from industrial production and sewage,secondly from automobile exhaust. Among them, the most serious pollution waslocated in the busy traffic sampling points, which was affected by the industry andautomobile exhaust.The concentration of strontium in the Sediment negatively correlated with87Sr/86Srratio, which became higher when the former decreased. The87Sr/86Sr ratio of theintertidal surface sediment from Quanzhou bay was in the range of0.7144~0.7190.The87Sr/86Sr ratio of the known anthropogenic sources had little difference with theone of the sampling site, indicating that the intertidal sediment of Quanzhou bay wasnot seriously polluted by Sr. |
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