Combined risk assessment method based on spatial interaction: A case for polycyclic aromatic hydrocarbons and heavy metals in Taihu Lake sediments

Owing to the complexity of sources and nonlinear dose-response relationship, evaluating the combined risks of pollutants in lakes remains a considerable challenge. In this study, we developed chose a non-parametric risk assessment method with source diagnostic and spatial interactions (LISA analysis) between the pollutants was developed for zoning the risks of combined pollution. Taihu Lake was chosen as the studied region, and the heavy metals and polycyclic aromatic hydrocarbons (PAHs) in the sediments were observed to test this method. Results showed that the developed method distinguished the hot spots of pollution in the eastern and northern Taihu Lake, and more than 50% pollutants were attributed to the combustion of petroleum fossil fuels. The main risk control area for heavy metals is mostly distributed in western Taihu Lake, accounting for 22.5% of the total area, while that for PAHs accounts for the smallest proportion, at only 3.4% of the total area. This study shows that the spatial interaction between pollutants could be a useful tool for evaluating the combined risks of pollutants, which can also provide better decision support for lake risk management.

Automated summary

By using a non-parametric risk assessment method and LISA analysis, the combined risks of heavy metals and PAHs pollutants in Taihu Lake sediments were tested. The study showed that the developed method could distinguish pollution hot spots in different regions of Taihu Lake and identified combustion of petroleum fossil fuels as the main source of pollutants.