RESUMO
In this paper, nutrient elements (N and P), heavy metals (Pb, Cu, Zn, Cd, Cr, Co, Ni, and Sn), and grain size in surface sediments of Baiyangdian Lake, northern China, are studied. We also analyze the spatial variation in elemental characteristics and undertaken a pollution risk assessment. By combining data with information on the river sediment characteristics, we use multivariate statistical methods to reveal the sources and variation of elements in sediments. The results showed that the average contents of heavy metals in surface sediments from the lake and associated rivers were higher than background values. Within the area of the lake, nutrient elements are relatively high in the northwest region but low in the southeast region, and heavy metals are relatively high in the middle of the lake but low in the southern and northern areas. The sequence of comprehensive pollution index (I) in sediments was Cd > Pb > Cr > Cu=Zn > Ni > Sn > Co, with Cd being assessed as severe pollution and other elements as moderate pollution, although severe pollution of Cr was found in the Zaolinzhuang area. The order of potential ecological risk coefficients (Eri) was determined as Cd > Pb > Cu > Cr > Ni > Zn, whereby Cd was associated with a strong potential ecological risk (except in the Caiputai area) and other elements were associated with a slight potential ecological risk. Differences in the lake sediment texture were found to be slight. Non-point source pollution after rivers flow into the lake was determined as the main reason for the spatial variation of elements in the surface sediments of Baiyangdian Lake, although point source pollution in the villages surrounding the lake should not be ignored, especially with respect to N, P, Pb, and Cr.
