An Assessment of the Heavy Metal Contamination, Risk, and Source Identification in the Sediments from the Liangtan River, China

Abstract

The contents of six heavy metals (HMs: Cr, Cu, As, Pb, Cd, and Zn) in sediments from the upper reaches of Liangtan River (LTR) were determined. The geo-accumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (RI) were employed to assess the HM contamination in the sediments. Pearson’s correlation coefficient analysis (PCC), principal component analysis (PCA), and cluster analysis (CA) were used to infer the sources of HMs. The average concentrations of Cr, Cu, As, Pb, Cd, and Zn were 44.63 ± 25.36, 31.40 ± 22.56, 4.66 ± 2.07, 29.20 ± 27.73, 0.25 ± 0.06, and 68.87 ± 104.62 μg/g, respectively. The Igeo indicated that the Cd contamination level was unpolluted to moderately polluted. The mean PLI was 0.97 ± 0.53, suggesting that the sediments were unpolluted, but close to moderately contaminated. The RI values indicated that the potential environmental risk of HMs in the sediments of the LTR was low. The results of PCC, PCA, and CA suggested that the Cr, Cu, As, and Zn in the sediment may mainly originate from natural processes; Pb mainly comes from human industrial and agricultural production activities as well as natural processes; and the main source of Cd may be the production activities of the surrounding chemical enterprises and chemical fertilizer application in farmland.

Long-Term Water Quality Monitoring: Using Satellite Images for Temporal and Spatial Monitoring of Thermal Pollution in Water Resources

“…The rising water temperatures of rivers are a major environmental hazard, directly and indirectly affecting the climate of neighboring regions, aquatic ecosystems, etc., but are scarcely studied regarding other causes of surface and groundwater contamination, such as chemical loads from industry or agriculture [48][49][50][51][52][53][54][55]. The considered remote sensing sources have been demonstrated to be useful tools to detect and quantify temperature changes in rivers, and the same goes for numerous water and environmental bodies (such as aquifers, wetlands, agricultural plots, etc.)…”

“…As shown in Figures 12 and 13, these pollutants have been discharged into the river and have caused an increase in water temperature. The accessibility and volume of these pollutants have facilitated their entry into rivers [52][53][54]. By analyzing the results of temperature changes along the Karun River, it can be concluded that the pollutant sources that were present in 1999 continue to increase the temperature of the Karun River to this day (over a twenty-year period).…”

Spatial Distribution, Risk Index, and Correlation of Heavy Metals in the Chuhe River (Yangtze Tributary): Preliminary Research Analysis of Surface Water and Sediment Contamination

“…Negative loading values for all heavy metals surface water and positive loading for sediments in the tributary suggest unique origins not captured by Factor 1. This indicates potential contributions from seasonal changes, sediment deposition, and water flow movement [74]. In sediment samples, Factor 1 explained 67.05% of the total variance and was strongly associated with concentrations of Cr, Ni, Zn, and Cd, indicative of common sources.…”