骆马湖沉积物营养物和重金属分布特征及生态风险评价OA

Taking sediments from Luoma Lake as the research object,the contents of particle size,total nitrogen(TN),total phosphorus(TP),organic matter(OM)and eight heavy metals(Hg,As,Cr,Ni,Cu,Zn,Cd,Pb)in collected columnar sediment samples were analyzed to investigate their distribution characteristics,sources and ecological risks.The results showed that the surface sediments in the northern part of Luoma Lake were coarse silt,while those in the southern part were fine silt.The organic matter content ranged from 12.0 to 28.2 g/kg,indicating moderate pollution(Grade Ⅲ).The total nitrogen content ranged from 546 to 1987 mg/kg,indicating heavy pollution(Grade Ⅳ).The total phosphorus content ranged from 506 to 746 mg/kg,also indicating heavy pollution(Grade Ⅳ).Organic matter was mainly derived from terrigenous input,while total phosphorus was significantly influenced by inflow from the Middle Canal and Yi River.Nutrients showed an increasing trend from north to south in spatial distribution and a decreasing trend from top to bottom in vertical distribution.The overall heavy metal content in the sediments was not high,with arsenic(As)being the most serious pollutant.The overall potential ecological risk of heavy metals was classified as low risk.Heavy metals showed no obvious spatial distribution pattern but exhibited surface enrichment characteristics in vertical distribution.