Health risk assessment of soil contamination with heavy metals in a child care center co-located in vicinity to small scale industrial area: Case study of Thailand

Abstract

Environmental impacts of small scale industries are still not well investigated, especially for estates where multiple small scale industries are clustered causing cumulative effects potentially impacting most vulnerable groups. This study aimed to investigate the concentrations of heavy metals (Mn, Fe, Ni, Cu, Pb, Al, Zn, and Cr) and the metalloid (As) in surface soils near the intensely active small-scale industrial area in Thailand, assess the contamination levels in the co-located child care center, and estimate potential human health risks from exposure to the heavy metals. Surface soil heavy metal(loid) elements were evaluated across a background area, area near main roads, a small-scale industrial area, and a child care centre. The concentrations of Al were found be the highest at all investigation sites, with the most elevated concentrations observed in the small-scale industrial area. The concentration of Pb in the industrial area reached 1176 mg/kg, exceeding the national standard and acceptable limit. Moreover, the contamination level for Cu, Pb, and Zn in the industrial area imply a considerable risk with enrichment factor EF > 40, and geo-accumulation index Igeo ≥5. Heavy metal levels (Ni, Cu, Pb) in the soil near the road and the child care center were similar, suggesting shared contamination sources. Conversely, Al, Zn, As, and Cr in the child care center had slightly higher concentrations than near the road but lower than the small-scale industrial area, indicating potential industrial influence on metal levels within the child care center. The principal component analysis showed Mn and Fe distributed in the background, while As, Pb, Ni, Cu, Al, Zn, and Cr accumulated in the small-scale industrial area. The findings indicate that small-scale industrial activities contribute to elevated levels of heavy metals in the soil, particularly within the child care center, posing significant ingestion risks, especially for children (HI > 1). Implementing contamination controls and monitoring urban soil are essential for public safety, especially for vulnerable groups like children.