Multivariate and geostatistical analyses of heavy metal pollution from different sources among farmlands in the Poyang Lake region, China

Purpose Intensive urbanization and industrialization activities have caused the continuous discharge of heavy metals into the soils of China's Poyang Lake region, where they pose a major threat to human health. Yet, the spatial characteristics of these heavy metals in farmland soils and their pollution sources in this region remain unclear. Materials and methods We collected 115, 84, 26, and 987 farmland soil samples with heavy metal pollution from different sources (industrial and mining enterprises, sewage irrigation, urban, and general farming) in the Poyang Lake region, respectively. Results and discussion Descriptive statistics revealed that 1.1% of As, 7.3% of Cd, 0.3% of Pb, and 0.2% of Hg concentrations did surpass China's Soil Environmental Quality Management Standard (GB 15618-2018). In addition, 32.8% of As, 74.4% of Cd, 89.2% of Pb, 45.0% of Cr, and 13.7% of Hg concentrations of soil samples exceeded the background soil concentrations of heavy metals in this region, notably Cd and Pb, whose maximum values were respectively 11.64- and 21.47-fold the background values. Compared with general farming areas, the other three pollution sources had significantly higher concentrations of As, Cd, Pb, Cr, or Hg in their soils. The results of principal component (PC) and geostatistical analyses showed that PC strongly related to mainly As and Cr was mainly influenced by natural characteristics while PC closely related to mainly Cd, Pb, and Hg was driven by mainly human activities in farmland soils from the four sources. Conclusions Factor loadings for the different sources showed As and Cr on the same PCs, and Cd, Pb, and Hg on the other PCs, confirming the association of the heavy metal pollution with its sources.