A better understanding of anthropogenic trace metal accumulation in farmland soils is crucial for local food safety and public health, especially for a rapidly industrializing region. In this study, soil samples at two depths were collected from a typical county in East China and analyzed for total concentrations of Fe, Al, Pb, Cd, Cu, Zn, Cr, and Ni. Results showed that trace metals like Pb, Cd, Cu, Zn, Cr, and Ni have accumulated in the regional farmlands, with average topsoil concentrations 1.62–1.77 times higher than their background concentrations in subsoil. However, they were still much lower than the limits of the Chinese Environmental Quality Standard for Soils. By the proper calculation of enrichment factor (EF), it was found that the accumulations of trace metals in the topsoil have been impacted by anthropogenic activities, which could contribute up to 40.83% of total metal concentration. Two principal components were extracted according to the results of principal component analysis (PCA) for EF values, which indicated two important anthropogenic trace metal sources. With the help of spatial distribution maps based on geographical information system (GIS), the anthropogenic sources of Pb, Cr, and Ni were determined to be mostly associated with atmospheric deposition from the central urban area. However, Cd, Cu, and Zn were further confirmed to originate from different agricultural sources. The anthropogenic Cu and Zn inputs were mostly related to pig manure application in the rural northern and southeastern areas, while extensive fertilizer application was identified as the major contributor to anthropogenic Cd accumulation in this region. Overall, the integrated application of EF, PCA, and GIS mapping is an effective approach to achieve the spatial assessment of anthropogenic impact on trace metal accumulation in regional soils.

To clarify the current state of heavy metal contamination in the sediments of lakes in China, the data on six heavy metals derived from the sediment samples of 71 lakes across China from 2003 to 2022 are collected in this study through meta-analysis. Uncertainty analysis is conducted using the Monte Carlo method to evaluate the heavy metals against cumulative characteristics, potential ecological risk, and toxicity indicators. The following conclusions are reached. (1) There is severe pollution in lake sediments in China. The concentrations of Cu, Pb, Zn, Ni, and Cd in lakes exceed their corresponding soil background values. Cr heavy metal contamination exceeded the soil background values in 54.5% of lakes. (2) Cd is the major pollutant in lake sediments across China, followed by Cu, Zn, Pb, Ni, and Cr in descending order. Lakes with higher ecological risk are predominantly concentrated in quadrants 2 and 3, indicating an overall high ecological risk status for Chinese lakes and significant potential ecological hazards. Pb and Cr are identified as the most toxic elements in lake sediments, with the lakes of higher toxicity mainly concentrated in quadrants 3 and 4. (3) Heavy metal pollution shows a significant trend of variation by region. The sources of heavy metals in lake sediments differ between the southern, central, and northern regions of China. In the lakes located in northern China, pollution is largely attributed to mining and industrial emissions, with agriculture as a less significant factor. In the central region, surface runoff and domestic sewage are the main contributors, while industrial and agricultural emissions play a minor role. In the south, industrial emission is the major source of pollution, with agricultural emission and natural factors being less significant.