Tissue Distributions Of Heavy Metals In Horseshoe Crabs And Their Relationships With Major Environmental Factors From The Intertidal Zone Along Beibu Gulf

The horseshoe crabs (Carcinoscorpins rotundicauda, Tachypleus tridentatus), which are the characteristic biological resource of Beibu Gulf, are typically marine species in this region. Heavy metal pollution in the intertidal zone has been the limiting factor in the survival of the horseshoe crabs and rational use of these natural resources, therefore, heavy metal pollution in horseshoe crabs should be paid more attentions.The research contents included:(1) Distribution and assessment of heavy metals (Cd, Cu, Pb and Zn) in various tissues (visceral mass, gill, carapace and muscle) of horseshoe crabs from the intertidal zone along Beibu Gulf; (2) Contents and pollution assessment of heavy metals in the sea water and surface sediments from the horseshoe crab habitats; (3) Correlation between heavy metal contents in various tissues of horseshoe crabs and major environmental factors. The primary conclusions of the present study were shown as below:(1) All metals were detected in various tissues of the horseshoe crabs. In all tissues of C. rotundicauda and T. tridentatus, the content of Zn had significant difference from that of Cu, while they were significantly higher than those of Cd and Pb; The metal contents in different tissues of the organisms were varied, and Cd, Cu and Zn contents expressed the highest content in the visceral mass, carapace and muscle, while the Pb content in the gill was relatively high.(2) The pollution status of heavy metals (Cd, Cu, Pb and Zn) in the horseshoe crab habitats was investigated, and the result stated that these heavy metals in the sea water and surface sediments were overall under low pollution level. The chemical speciation of heavy metals in surface sediments stated that Cd, Pb and Zn in sediments could cause potential harm to the organisms and ecosystem with relatively high bioavailability.(3) Pearson correlation between heavy metal contents in various tissues of horseshoe crabs and major environmental factors was analyzed. The results indicated that Cd, Pb and Pb in visceral mass exhibited significantly positive correlations with their corresponding exchangeable metals in sediments. Pb, Cu in gill and Pb in carapace were significantly positive correlated with their corresponding metals in sea water. These feature reflected the potential sources of partial metals in horseshoe crabs.