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The purposes of this study are to understand distributions and historical pollution records of heavy metals in sediments from the Kaoping coastal areas. Surface sediments were collected from coastal areas of the Kaohsiung 1st Harbor, the Kaohsiung 2nd Harbor and the Kaoping River. Three gravity cores were also collected from the Kaohsiung Harbor near the Chien-chen River mouth, coastal areas adjacent to the Kaohsiung 2nd Harbor and the Kaoping Estuary. Distributions of heavy metals( Al¡BCd¡BCr¡BCu¡BFe¡BMn¡BNi¡BPb¡BZn), total organic carbon(TOC), total nitrogen(TN) and grain size in sediments were investigated. 210Pb chronology and stable lead isotope ratios( 206Pb/207Pb¡B208Pb/206Pb¡B208Pb/207Pb) were applied for revealing the historical records of metal pollution. Experimental results show that sediments in the Kaoping coastal areas were polluted substantially with Cr, Pb and Zn. The metal pollution were relatively significant at the Kaohsiung 1st Harbor, the Kaohsiung 2nd Harbor, three outfall fields, nearshore areas (Da-lin-pu, Kaoping River, Tungkang River, Linpan River and Tapong Bay) and inner of the Kaoping Submarine Canyon. Distributions of heavy metals in sediments from the Kaohsiung Harbor coastal areas were apparently influenced by the distributions of grain size and organic matter. The metal pollution is heavier within the Kaohsiung Harbor than in coastal areas adjacent to the Harbor. The Chien-chen River is one of major sources of metal pollution in the Kaohsiung Harbor. According to 210Pb dating, the sedimentation rate near the Chien-chen River mouth is about 0.78 cm/y. The onset of rapid increase of metal pollution was in 1958, the time coincident with the re-construction of the Kaohsiung Harbor. The Kaoping Submarine Canyon played a major role on the transport and deposition of heavy metals discharged from the Kaoping River. The variation of topography and current results in enrichment of fine sediments in the Kaoping Submarine Canyon, where heavy metals were likely accumulated and enriched in fine sediments. Significant metal pollution beginning around 1972 was revealed from a sediment cone near the Kaoping Estuary. Anthropogenic metals may be released from the industrial parks along the Kaoping River. |
