The Migration and Enrichment of Heavy Metals in Tengchong Watershed with Volcanic Rock Distribution
While the impact of heavy metal pollution from human activities is significant,the impact of heavy metal pollution in the watershed should not be ignored.The high geological background of the igneous rock distribution area often contains high levels of transition metal elements,including Cr,Ni,and Cu,which are mainly found in soils and sediments in the watershed.These metals can cause persistent ecological harm to the watersheds.To understand the migration and enrichment patterns of heavy metal elements in the soils and sediments of igneous areas,we studied two watersheds,Longchuan River and Shahe River,in the distribution area of Tengchong igneous rocks in Yunnan Province.Systematic samplings of bedrock,soil and sediment were performed.The results showed that the mineral composition of sediments and soils in the both watersheds consisted mainly of quartz,feldspar,clay minerals,and a small amount of carbonate.With a decrease in feldspar during the weathering process,the clay minerals increased significantly,and the heavy metal elements were enriched with the increase of clay minerals.The contents of Cr and Ni were enriched in soils with a linear relationship with the total clay minerals(Cr:R2=0.381 7;Ni:R2=0.579 7).The contents of Cr,Ni,Zn,and Pb in sediments were linearly related to kaolinite and mica illite mixed layer(R2=0.43-0.72).Heavy metals such as Cu,Zn,and Pb were enriched in sediments,and their mass transfer coefficients were linearly related to kaolinite,mica,and illite mixed layers in Longchuan River sediments(R2=0.58-0.79).Clay minerals play an important role in the enrichment and transport of heavy metal elements.
Tengchong,Yunnanmigration and enrichment of heavy metalssoilsediment
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