The Conversion,Migration And Health Risk Assessment Of Heavy Metals Pollution

Over the rapid development of industries in recent decades,the increasing of life quality is continuously accompanying with the aggravation of environmental pollution,one of which is heavy metals contamination.Deltas and rivers are the cradles that gestating civilization of mankind,they are also deeply affected by human activities with the development of human civilization.With the operation of multiple indutries,massive exogenous heavy metals are discharged into deltas and rivers,which pose a significant threat on environment in deltas and rivers.Therefore,it is urgent needed to concern the pollution of heavy metals and enforce more effective management in deltas and rivers,which are crtical to continue civilization of mainkind.This study is based on a comprehensive investigation at home and abroad,the distrbution of heavy metals in soils and their impacts of delta were determined by the widely investigation of heavy metals pollution in delta.The diffusion and migration of heavy metals and their controlling factors in soils of delta were found out via the testing of heavy metal concentration and soil properties in soil at different depths.The long-term health effects of heavy metal pollution in delta was also evaluated that relying on the assessment of heavy metals.The heavy metals of surface water,sediment and wild fish were tested to clarify the accumulation and conversion of heavy metals in aquatic ecosystem of river,establish the linkage between the conversion of heavy metals and their chemical forms.Seven heavy metals were selected to determine the longterm health effects via the assessment of health risk,which will not only provide a basis for the prevention of heavy metal pollution,but also promote the identification of long-term ecological risks of heavy metals pollution.The obtained results:(1)The investigation of heavy metals pollution were undertaken to ascertaine the spatial distribution and sources of heavy metals in soils of Yellow River Delta,then the pollution status of heavy metals in soils of Yellow River Delta were determined by the assessment of potential ecological risk.Based on the EF values in defferent layer of soil,As was found to be the most mobilizable,which can move deep inside the lower layer of soil,followed by Cd and Pb,which can be partially or completely blocked by the middle layer of soil.(2)Based on the investigation of heavy metals pollution in soil of the Yellow River Delta,the health risk assessment was employed in figuring out the potential health risks of heavy metals via different exposure routes.Ingestion,rather than skin contact and inhalation,was considered to be a vital route for heavy metal exposure.The carcinogenic risk of Arsenic are significantly higher so that it can be treated as an critical threat to public health.(3)The investigation in surface water and sediments of Liujiang River Basin were carried out to determine the distribution,sources and pollution status of heavy metals.The accumulation and transformation of heavy metals and their impacts in rivers were comprehensively analysed.The reversion of the impacts of hydrochemical fluctuations on the accumulation of heavy metals was found to be blamed on the the emission of acid wastewater,the conversion of Cd,As,Pb and Zn were confirmed,which supported by their specific speciations,Cd contamination should be treated as a critical environmental threat in Liujiang River Basin.(4)The investigation in Liujiang River Basin were undertaken to ascertain the pollution and bioenrichment of heavy metals among wild fish in different fish species and sampling areas.The comprehensive analysis combining with water chemistry and properties of sediment were carried out to figure out the bioaccumulation of heavy metals among wild fish.Linkage the bioenrichment of heavy metals among wild fish with chemical forms of heavy metals in sediments provides provides a scientific basis for fishery supervision.(5)The wild fish that collected from anglers provides a vital chance to gauge the health risk of anglers from angling fish that they consuming.Therefore,the results of investigation that related to the bioaccumualtion of heavy metals among wild fish that angling from Liujiang River Basin were employed to ascertain the pollution status and edible security among these fish,moreover,the waterways in suburban areas were confirmed to be more suitable for fish angling in accordance with the calculation of recommanded comsumption of these fish collected from different areas,which is conducive to guide fish angling and its related fish consuming.