Distribution Characteristics And Pollution Evaluation Of Heavy Metals In Sediment Of Zhuzhou Section Of Xiangjiang River

Xiangjiang River is one of the important tributaries of the Yangtze River Basin and the largest river basin in Hunan Province.Xiangjiang River is the largest source of drinking water in Hunan Province.The water quality of Xiangjiang River is of great significance to the health,living standards and social economic development of the people of Hunan Province.Heavy metals convert to each other in solid and liquid forms in water.When heavy metals are distributed in a solid state,they will show obvious regularity and are less affected by the outside world.The sedimentary characteristics of heavy metals in river sediments record changes in human activities and environment,reflecting the evolution of water ecology,and also recording changes in heavy metals over time.In this paper,the sediments of the Zhuzhou section of the Xiangjiang River are studied,and the pollution of heavy metal elements such as chromium,cadmium,lead,arsenic and mercury is studied.Three sampling sections of the river sediments(Xiawan,Lusong Bridge,Jianning Bridge)were selected in the Zhuzhou section of Xiangjiang River.24 sediment samples were taken and the samples were sampled to obtain chromium,cadmium,lead,arsenic,mercury and The content of five heavy metal elements,pH value and organic matter content.Through the accumulation of the index method,the pollution load index method and the potential ecological hazard index evaluation method to evaluate the heavy metal pollution in the Zhuzhou section of Xiangjiang River.The vertical distribution characteristics of heavy metals in river sediments show that the heavy metal elements such as chromium,cadmium,lead,arsenic and mercury in the Xiawan section are most polluted at 60-70,20-30 cm,at 20-30,30-40,60-.The pollution level is the next at 70 cm;the heavy metal elements chromium,cadmium,lead and arsenic in the reed profile are the most polluted at 50-60,70-80 cm,and the pollution level is 50-60,60-70,70-80 cm.In the Jianning section,heavy metal elements such as chromium,cadmium,lead,arsenic and mercury are most polluted in the deep layers of 60-70 and 70-80 cm;in the 30-40,50-60,60-70 cm,the degree of deep pollution is second.Heavy metal chromium,cadmium,lead,arsenic and mercury all showed the same law at three sampling points.From upstream to downstream,from Jianning to reed,to Xiawan,the heavy metal content showed a decrease and then increased.This indicates that the heavy metal elements in the water body are purified and diluted by the water body during the journey from Jianning to Reed,resulting in a decrease in heavy metal content in the river water.After the water body flows to Xiawan,the heavy metal content in the water increases sharply,indicating that the reeds to the Xiawan section may have heavy metal materials added.There is a significant correlation between heavy metal elements such as chromium,cadmium,lead,arsenic,mercury and organic matter in the Xiawan section and the reed section,while the correlation between pH value and chromium,cadmium,lead,arsenic,mercury and organic matter is not Significant.The correlation between heavy metal elements such as chromium,cadmium,lead and mercury on the Jianning section is significant,while the pH value is only related to cadmium and lead.Organic matter and heavy metals such as chromium,cadmium,lead,arsenic,mercury and pH There is no significant correlation between the values.From the ground accumulation index method,it can be seen that the pollution level of Cr on all three sections is 0,Hg only causes no ~ neutral pollution in the Xiatai section,and Pb causes no ~zhong pollution in the reed section,in Jianning and Xiawan.The section caused moderate pollution,just as no pollution occurred in the reed section only 60 cm ~ 80 cm,while in the Xiawan section and the Jianning section reached medium ~ strong,intensity pollution,cadmium in the reed section only ~ Neutral and moderate pollution,but reached a medium-strong,strong pollution in the Jianning section,and reached a strong ~ extremely strong pollution at 70 cm,and reached a strong ~ extremely strong and extremely strong in the Xiawan section Degree of pollution.The degree of pollution of heavy metal pollution is ranked as chromium <mercury < lead < such as < cadmium,and the pollution degree of each section is ranked as reed <Jianning <Xiawan.From the potential ecological hazard index evaluation method,it can be seen that heavy metal chromium has no ecological hazard in Xiawan,Lusong and Jianning sections,and mercury only reaches a slight ecological hazard in Xiawan section,such as in Xiawan and Jianning sections.Strong ecological hazard,but did not reach ecological hazard in the reed section,cadmium reached a strong ecological hazard in the reed section,and reached a very strong ecological hazard in the Xiawan and Jianning sections.The RI of the reeds did not exceed 150,and did not cause ecological hazards.Jianning was second,and it achieved strong ecological hazards and strong ecological hazards.The Xiawan section was the most polluted,and all levels of the section reached a strong ecological hazard.The degree of pollution of heavy metal pollution is ranked as CR = lead < mercury column < according to cadmium,and the degree of pollution of each section is ranked as reed <Jianning <Xiawan.From the pollution load index method,it can be seen that the degree of pollution in the reed section is the smallest,moderate pollution,no pollution at 20 cm to 50 cm,and the Xiawan and Jianning sections have reached extremely strong pollution.The pollution degree of each section is Jianning = Xia Bay>Reeds.