Seasonal variation and ecological-human health risk assessment of toxic elements and microbial contaminants in a municipal landfill, central Thailand

Abstract

Landfilling is a common method for disposing of municipal solid waste (MSW) in Thailand. Much of this waste is deposited in open dumpsites lacking adequate environmental and health safeguards. A long-term study was conducted in the Chong Sarika district, the Lopburi provincial landfill, and their surrounding habitat. The results revealed that soil bacterial concentrations were highly contaminated during the dry season, particularly for yeast and molds, with levels at 59.38 ± 96.47 CFU g-1. Further, the total coliform community was 56.34 ± 100.3 CFU g-1, indicating significant contamination. The physicochemical and biological indices indicated that surface water quality during the rainy and dry seasons was below standard limits, except for electrical conductivity (EC) in the dry season. Heavy metal concentrations in soil were quite high for AI, Cd, Fe, Mg, Ni, Pb, and Zn in the wet season. However, the overall average was still safe. The Igeo , CF , and ER levels of Cd and Cu were present at a considerable degree; however, Cd concentrations were statistically significantly higher in the wet season. Calculated RI and PLI levels revealed moderate ecological risk and pollution in this landfill, respectively. In addition, the calculated Hazard Quotient (HQ) and Total Cancer Risk (TCR) of heavy metals were within the acceptable risk for human health. This study emphasizes the need for soil and water management in community households. A participatory approach was applied to establish continuous practices among residents and stakeholders to improve waste management and prevent future conflicts.