[Potential Source Identification and Ecological Risk Assessment of Heavy Metals in Surface Soil of Heze Oil Peony Planting Area Based on PMF-PCA/APCS and PERI].

To study the sources and potential risks of heavy metals in soils of characteristic agricultural product producing areas is of great significance for the scientific management and safe utilization of soil and crop resources. The contents of heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the 254 surface soil samples collected from the Heze oil peony planting area were determined. The content characteristics and correlation of heavy metals were analyzed using multivariate statistical methods. The sources of heavy metals in topsoil were analyzed using Igeo, PMF, and PCA/APCS. The ecological risks of the eight heavy metals were assessed through the potential ecological risk index (PERI). The results showed that the average contents of seven heavy metals in the soil were basically consistent with the background values of soil elements in Heze City, except that the average value of Cd was 1.44 times higher than the background value in Heze City. Correlation analysis and cluster analysis revealed that Pb, Hg, and Cd elements in the soil were greatly affected by human activities in the later period. The sources of eight heavy metals in the study area were natural sources, agricultural fertilizer sources, industrial coal sources, and domestic transportation sources, with the contribution rates of 81.31%, 15.45%, 2.74%, and 0.50%, respectively; 84.25% of the sites in the study area were at slight ecological risk, whereas the moderate risk and strong risk sites accounted for 14.96% and 0.79%, respectively. Among them, Cd and Hg were the dominant elements of ecological risk in the study area.

Ground water copper levels in the seawater intrusion area and the possible physical and chemical dynamics.

Seawater intrusion, a common geological process along the coastal zones, changes the groundwater properties, which are potentially associated with the groundwater copper (Cu) levels. However, there are no studies on the details of groundwater Cu levels affected by seawater intrusion. The groundwater in the seawater intrusion area of Buzhuang Town was sampled to detect the effect of seawater intrusion on groundwater Cu levels. The Cu levels in the local groundwater range between 0.92 and 4.99 µg L-1, which averages about 5 times than those in the non-intrusion area. The Cu deviations (ΔCu) are positive, and increase with more intrusion of seawater. Simulation experiments also confirm that more Cu leaches from sediments when more seawater or brine water is mixed in. The groundwater Cu levels are positively correlated with TDS, Cl-, Br-, SO42-, HCO3-, Na+, K+ and Mg2+. The Cu-bearing minerals in the local groundwater are under-saturated. The CEC of the sediment for the simulated experiments decreases with more mixture of seawater or brine water. CuCO03, Cu(OH)02, CuHCO3+, Cu(CO3)22-, CuCl2-, Cu2+ species in the local groundwater are obviously higher than those in the non-intrusion area, and the levels of CuCl2-, Cu+, CuCO3, Cu2+, CuSO4, CuOH+, CuCl+, Cu2(OH)22+ are positively correlated with the degree of seawater intrusion, indicating the important role of Cl-, HCO3-, OH- complexation on groundwater Cu levels. Thus, ion competition and complexation are the important dynamics of groundwater Cu enrichment along the coastal zones. A new enrichment model of groundwater Cu in the seawater intrusion area is presented. Seawater intrusion should be taken into consideration when the enrichment mechanisms of groundwater Cu are discussed.