Heavy metal and arsenic (As) concentrations in the overlying water of Lake WLSH from 2013-2017 to evaluate the water quality of the lake. Heavy metal and As concentrations in Lake WLSH surface sediment from studies performed between 2009-2017 were analyzed of heavy metal geo-accumulation, potential ecological risk and toxicity data for Lake WLSH surface sediment was performed to allow heavy metal and As pollution of Lake WLSH surface sediment to be described clearly, objectively, and comprehensively. The following four main conclusions were drawn. (1) The water quality index of the overlying water showed a tendency of slight pollution in the lake from 2013 to 2017. (2) Pollution by the heavy metals (Cu, Zn, Pb, Cd, Cr) and As in Lake WLSH should be given increased attention. (3) The geoaccumulation indices showed that Cd is the most critical pollutant and that the probabilities of Lake WLSH sediment being slightly polluted and moderately polluted were found to be 72.8% and 11.3%, respectively. (4) Cd is the main contributor (75.2%) to potential ecological risks, and although As is at a low toxicity level, its toxicity-risk contribution is higher than that of other metals (approximately 31%). (5) Positive matrix factorization (PMF) model results indicated that industrial and agricultural resources are the main suppliers of heavy metals to Lake WLSH sediment, contributing 43.2% and 42.6% of the heavy metals and As. The summarized results and conclusions can help the local government further understand heavy metals and As pollution in Lake WLSH and develop corresponding pollution-control measures. This study can also serve as a reference for future research on the heavy metals and As pollution of sediment in Lake WLSH and other lakes.