Abstract
Soil heavy metal contaminated sites with multiple sources of pollution have caused worldwide public concern. However, the lack of correlation of risk assessment or source identification of heavy metal leads to unclear direction of source governance. Although previous studies have involved different risk assessment, few attempts have been made to establish a link between them. In order to design a comprehensive risk assessment system, it is necessary to identify the specific source risks and the correlation and comparison between environmental risk assessment. In this paper, a methodology was established by combining source apportionment of ecological risks and human health risks (SERA) to characterize the sources and source-specific risks of heavy metals in soil. Positive matrix factorization (PMF) model was used to identify and classify potential sources of heavy metals in the study area. According to the results, they will be incorporated into the environmental risk model to evaluate environmental risk of the identified sources of heavy metals. The results showed that concentrations of Cd and Hg were highly above the background values, indicating a moderate enrichment. It was worth noting that the source contributed ecological risk index (SCEI) of Hg, with the value of 51.16 contributed mainly by the pollutant sources of waste treatment, has reached moderate ecological risk. The SCEI of Cd contributed by industrial activities (the wastewater and dyeing process) showed the most predominant source of contribution. The source contributed human health risk index (SCHI) of As contributed most by pollutant sources of agriculture activities. Overall, the modified total health risk posed by soil heavy metals SCHI was 1.11E+00, showing potential risk to the residents. This study provides a new insight for the treatment of mutil-sources of soil heavy metal pollution and also some reference value for the improvement of the risk assessment system.the main finding: Exploring a methodology (SERA) to quantitatively characterize the relationship between pollutants sources and environmental risk assessment based on source contribution.
Environmental Risk Assessment of Heavy Metals in Sediment of Nun River around Gbarantoru and Tombia Towns, Bayelsa State, Nigeria
