Assessment and trend prediction of the environmental capacity of heavy metals in surface sediments of the Dongping Lake,North China
The environmental capacity of lake sediments serves as a significant indicator for assessing the environmental carrying capac-ity of lake systems,effectively reflecting the stability and sustainability of lake systems.This study investigated the Dongping Lake in the lower reaches of the Yellow River basin by determining 11 heavy metal elements,including As,Cd,Cr,Co,Cu,Hg,Mn,Ni,Pb,Tl,and Zn,in the sampled surface sediments.It delved into the spatial distributions of heavy metal contents and environmental carrying capacity using statistical analysis and geographical information system(GIS)technology.Moreover,it predicted the trend of environmental capacity changes of heavy metals at a centennial scale.The results indicate that:(1)The maximum content of As in the surface sediments of the study area exceededits risk screening value(allowable limit)for soil contamination,whereas those of other ele-ments were below corresponding allowable limits;(2)The average single environmental capacity index(Pi)values of heavy metal ele-ments decreased in the order of Hg,Pb,Cr,Ni,Zn,Cd,Cu,Co,Mn,Tl,and As.Among these heavy metal elements,As dis-played overload level and warning level points,whereas Mn and Tl manifested warning level points.The composite capacity index(Pi)was calculated to be between medium and high capacity levels.The composite capacity level measured based on the inferior level of Pi suggests a medium capacity to overload level distribution in the study area;(3)The static annual capacity limits of heavy metal ele-ments decreased in the order of Mn,Zn,Cr,Ni,Cu,Pb,As,Co,Tl,Cd,and Hg,whereas the dynamic annual capacity limits de-creased in the order of Mn,Zn,Cr,Ni,Pb,Cu,Co,As,Hg,Cd,and Tl.The static and dynamic capacity limits will show a steeply to gently decreasing trend in the 5～40 years and 5～15 years,respectively,followed by a gentle and stable trend.Regardless of the number of years,the average dynamic annual capacity limit is higher than the average static one,suggesting a high environmental car-rying capacity.This study reveals the current status and future trends of environmental capacity in the Dongping Lake,providing a sci-entific basis for the environmental quality assessment and ecological conservation and restoration of the lake.
surface sedimentheavy metalenvironmental capacitytrend predictionDongping Lake
国家科技期刊平台
NSTL
万方数据
