Critical source apportionment and source-oriented risk-based evaluation of toxic metals in soils and rice around brick kiln area

Toxic metals in soil and rice have negative consequences for the ecology as well as human health. Computing soil pollution status and human health hazards from several sources might assist to prioritize sources and manage concerns. The present study was conducted in a brick kiln area of Bangladesh to know the metal contamination status in soils and rice. Several multivariate statistical approaches, e.g., the positive matrix factorization (PMF) model, were used to characterize metal sources in soils. Ecological risks as well as the PMF-HHR model were applied to assess source-based health risks. The PMF model identified that Pb (85.9%) was predominantly contributed by fuel combustion, Cd (77.1%) resulted from agricultural practices, Ni (76.5%) originated from soil parent materials, and Cu (76.3%) was yielded from vehicular emission. According to ecological risk, the potential ecological risk index (179.79), Nemerow pollution index (1.85), and NIRI (166.35) showed considerable risk, slight contamination, and high risk, respectively. Vehicular emission (42.5%) and agricultural practices (27.5%) were the largest sources for causing non-carcinogenic risks in the soil whereas fuel combustion (32.34%) and agricultural practices (25.75%) resulted in carcinogenic risks. The hazard index value due to the consumption of rice were 1.83E+00 and 2.41E+00 (HI > 1) for adults and children indicating considerable non-carcinogenic risks. Cancer risk for Cr and As exceeded the safety limit (1.0E-04) suggesting potential cancer risk. Furthermore, the non-carcinogenic and carcinogenic risk values were higher in children than in adults. The integrated method proved beneficial for assessing source apportionment and quantifying HHR from sources in brick kiln soils and rice, resulting in appropriate recommendations for decreasing pollution and safeguarding human health from the sources.