Abstract
This paper combines environmental science, inorganic chemistry, water quality monitoring and other disciplines, and uses several representative evaluation methods (WQI, Pn, I-geo, RI) for heavy metals in water and sediments. A preliminary assessment and source analysis of heavy metals (Cd, Cr, Fe, Mn, Zn, Cr, Ti, Ni, Cu, As, Pb, Sr) in water and surface sediments of the Fenghe River Basin, Shannxi Province, China was carried out in this study. Results indicate that most of the heavy metals in water are below national water quality standards. Exceptions include Mn, which exceeds national tertiary standards and Cr, which exceeds national drinking water standards. Most heavy metals in the sediments exceed the environmental standard values except Ni. Water quality index (WQI) and Nemero index (Pn) showed the same trend in contamination levels of sampling sites. According to the Geological Accumulation Index method (I-geo) and the Potential Ecological Risk Index method (RI), high concentrations of Cd poses a high ecological risk in some sampling locations. Pearson Correlation Analysis (CA), Hierarchical Clustering Analysis (HCA), Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF) models are used to explore the relationships and sources of heavy metals. In general, upstream sources are similar, and middle and lower reaches are easily clustered into a large category except for some specific sampling points. For example, metals in sampling site FHK mainly come from surrounding residents and farms and heavy metals attributes in sampling site SLQ relate to the fact that municipal sewage is collected and treated. The factors or sources of heavy metals in water and sediment are revealed in detail through PMF models. In the water, the average contribution rate of these four source factors for heavy metals is 36.8%, 11.7%, 9.4% and 42.0%, while the average proportion of these four factors for heavy metals in sediment is 8.0%, 29.2%, 23.9% and 38.9% respectively. Results show that the main sources of pollution in the region are urban construction and transportation, electronics industry, machinery manufacturing, tourism and agriculture. These sectors should therefore be given sufficient attention in the prevention and management of heavy metal pollution.
Heavy Metals in Water and Surface Sediments of the Fenghe River Basin, China: Assessment and Source Analysis
