[Source Apportionment and Pollution Risk Assessment of Heavy Metals in Sediments of Huixian Wetland Based on PMF and APCS-MLR Models].

Abstract

Based on the analysis of sediment samples from 14 sites in the Huixian Wetland， the content characteristics of eight heavy metals （Cu， Pb， Cd， Cr， Zn， Ni， Hg， and As） were investigated. The geoaccumulation index and potential ecological risk index were employed to assess the risks of these heavy metals. Correlation analysis， cluster analysis， absolute principal component scores-multiple linear regression （APCS-MLR）， and positive matrix factorization （PMF） were used in combination to identify and quantify the pollution sources and their contributions. The results are as follows： ① The average concentrations of all eight heavy metals exceeded background values， with Cd surpassing the screening values specified in the Soil Environmental Quality - Risk Control Standard for Soil Contamination of Agricultural Land （GB 15618-2018）. ② The geoaccumulation index evaluation indicated that Cd falls into the category of moderate pollution， Zn falls into the category of slight to moderate pollution， Hg， Ni， Cr， and Pb are categorized as slight pollution， and As and Cu are considered unpolluted. ③ The potential ecological risk index assessment revealed that Cd （245.91） poses a very high ecological risk， Hg （134.59） poses a high ecological risk， and other elements pose slight ecological risks. The mean comprehensive ecological risk index for the study area is 433.33， indicating a strong overall potential ecological risk. ④ APCS-MLR identified four pollution sources： agricultural sources， natural and agricultural sources， atmospheric deposition and domestic sources， and unidentified sources （transportation and agricultural sources）， with contribution rates of 33.16%， 15.75%， 9.50%， and 41.59%， respectively. PMF identified three pollution sources： atmospheric deposition and domestic sources， natural and agricultural sources， and transportation and agricultural sources， with contribution rates of 21.92%， 35.24%， and 42.84%， respectively.