Health risk assessment of potentially toxic elements in common cultivated rice (Oryza sativa) emphasis on environmental pollution

Abstract

Heavy metal accumulation and contamination is a global serious dilemma due to toxicity, abiotic characteristics, abundant resources, and cumulative behavior of heavy metals. This evaluation aimed at measuring and evaluating seven heavy metals (Ni, Cu, As, Zn, Pb, Cr, and Cd) content in rice (Oryza sativa) and associated health risks was carried out for consumers in Khuzestan Province, Iran. We choose 20 stations in 5 strategic regions of rice cultivation. The average carcinogenic risk of arsenic by rice consumption in Khuzestan Province was estimated to be 3 adults and 4 children per 10,000 populations. The average concentrations of heavy metals in rice and rice field soils were as follows: In rice: Ni (0.38 ± 0.25), Cu (5.29 ± 3.04), As (0.087 ± 0.066), Zn (17.89 ± 3.35), Pb (0.17 ± 0.08), Cr (0.69 ± 0.25) and Cd (0.058 ± 0.027) mg kg-1.In soils: Ni (49.32 ± 16.71), Cu (36.69 ± 19.74), As (5.02 ± 3.42), Zn (71.20 ± 12.72), Pb (10.99 ± 4.299), Cr (81.23 ± 22.31), and Cd (0.18 ± 0.072) mg kg-1, respectively. Nickel showed the highest standard deviation of the SPI with an average of 2.38 ± 0.81. The average CPI for rice was in the following descending order: Cd (0.95 ± 0.45)> Ni (0.92 ± 0.64)> Pb (0.84 ± 0.41)> Cr (0.69 ± 0.25)> As (0.65 ± 0.52)> Cu (0.53 ± 0.31)> Zn (0.36 ± 0.068). Cadmium and nickel respectively showed the highest and lowest BAF with an average of 0.302 and 0.0067. According to the US Environmental Protection Agency (USEPA) classification, the overall HI for adults in four regions was at Level 3 (medium) and for children in two regions at Level 4 (high). The corresponding values for cadmium were 5 adults and 8 children per 100,000 populations. This means that rice consumption in Khuzestan Province could cause cancer during the lifetime of rice consumers.