The Characteristic Of Heavy Metal From Lacustrine Sediment Of Lake Douhu In Fujian

With the increasing environmental problems,global change has become the focus of attention of many scientists.The lake is the node of the terrestrial ecosystem,which is an important part of the natural circulation.It is the ultimate repository of the river basin material.The sediments faithfully record the information of various environmental changes in the lake area.Therefore,the lake sediments have an irreplaceable advantage in the study of the response of the global and regional,as the study of land changes in the important information carrier.In recent years,with the rapid expansion of economic and industrial development,environmental pollution has become one of China’s urgent problems to be solved.Among the various pollutants,heavy metals,including Cu,Zn and Pb,are one of the most important species.Heavy metals mainly from industrial production such as mining,smelting,coal combustion,waste incineration and fossil fuel combustion.Because heavy metals can accumulate in a vital organ of the living body and cause damage to the circulatory system and the central nervous system,the effects of heavy metal pollution are extremely serious.In the Fujian area,heavy metal pollution has been done,a lot of valuable work reveal its level,source,spatial distribution,seasonal distribution and the reasons for control measures.However,there is little research on the long-term trend of heavy metals.Mountain lakes such as medium-high lake or high-altitude lake that are less affected by local human activities are considered to be good natural archives of past environmental changes.Located in Douhu Mountain,Fujian Province,the lake(987 meters)is one of the few days in Fujian Province,the lake is mainly from the precipitation of atmospheric precipitation,sedimentary environment is stable,and weak by human activities.Thus,the Lake Douhu sediments sequence can well record past environmental changes.In this study,the enrichment factor and the sedimentation flux of the heavy metal elements.in the sediments were analyzed by using the sedimentary cores drilled at the center of the lake in 2014.The concentration of heavy metal elements and the ratio of lead isotopes were analyzed.Correlation analysis,principal component analysis,cluster analysis,back trajectory and earth atmospheric model were used to cluster and source the heavy metal elements,and compared with the development history of potential heavy metal source areas around the study area.The potential ecological risk assessment method is used to evaluate the pollution of heavy metals in the sediments of the Lake Douhu over the past 100 years.Our study indicates,1)The results show that the pollution of heavy metals in the Lake Douhu sedimentary core is light,but it has a tendency to increase gradually in the past 100 years and needs to be paid enough attention.2)Based on the correlation analysis,principal component analysis and cluster analysis,it is concluded that the two main sources of heavy metal elements in columnar sediments are anthropogenic sources such as industrial emissions,fossil fuel combustion and natural sources.The contribution rates are 70.19%and 19.66%respectively.3)In the 1960s and 1990s,the concentrations of Cu,Zn and Pb increased gradually in the 1960s and 1990s,and could be affected by the discharge of industrial waste gas and transportation emissions from the surrounding areas such as Japan.And other people for the activities of the impact of the 90’s Lake Douhu heavy metal concentration significantly improved a "step",and China’s reform and opening up after the development of industry and the use of leaded gasoline in the 1990s led to excessive emissions of lead in the environment;into the 21st century,atmospheric heavy metal deposition Flux between 2000 and 2003 there is a slight decline,it may be completely prohibited with the use of leaded gasoline is closely related to the 2003 to 2009,the rapid increase in sediment flux,and reached the peak of nearly a hundred years,the stage China’s energy consumption is mainly coal-based,coal-fired pollution accounted for the lead.Since 2009,man-made heavy metals have a downward trend,probably because of the increase in investment in environmental pollution in Fujian Province,and,with China’s rapid development,people’s living standards improve,people’s environmental awareness is growing,the government implemented a more stringent of the air pollutants industrial emission standards.4)The level of lead began to increase gradually in the North American and European,since the late 19th century or in the 1900 years since the beginning of the industrial revolution,from the man-made sedimentation flux(or enrichment factor)of the lead in the northern hemisphere.The maximum level of lead,and then due to the gradual withdrawal of leaded gasoline and the implementation of more stringent pollutant discharge standards,the rapid decline in lead levels.China’s records show that lead-based aggregate flux trends reflect a significant increase in lead pollution since the 1980s and 1990s due to industrial development.