Evaluation, source apportionment and health risk assessment of heavy metal and polycyclic aromatic hydrocarbons in soil and vegetable of Ahvaz metropolis

Abstract

Macronutrients, heavy metals, and polycyclic aromatic hydrocarbons (PAHs) were investigated in agricultural soils and vegetables of Ahvaz metropolis to assess the contamination, potential sources, bioconcentration, and related health risks for local residents. For this purpose, 105 and 26 vegetable and soil samples from different parts of the study area were collected and analyzed. The determination of PAHs was carried out using gas chromatography–mass spectrometry and concentrations of elements were measured using ICP-MS methods. Calculated enrichment factor, contamination factor and ecological risk of metals showed that agricultural soil is moderately polluted with regard to Cd and P. The results of positive matrix factorization (PMF) and principal component analysis (PCA) (PCA) demonstrated that Cd, K, and P probably result from anthropogenic sources. One-way ANOVA indicated that heavy metal concentration in different vegetables varied significantly at p ≤ .05. BCF analysis indicated that most analyzed vegetables act as accumulators for K, P, and Mo. The results of PCA (PCA) and concentration ratios of various PAHs demonstrated that high molecular weight (HMW) PAHs in soil is mainly from gasoline and diesel exhaust combustion while, low molecular weight (LMW) PAHs are mostly originated from petrogenic source. Measured soil organic matter and clay content significantly correlate with high molecular weight PAHs concentration. The common practice of using kerosene as an herbicide on parsley and dill farms in Ahvaz area seems to be the major source of low molecular weight PAHs in vegetable samples. Calculated bioconcentration factors indicated that all investigated vegetables are accumulators of Nap, Flu, Phe, BaA, and Chr. Furthermore, calculated human risk indices indicated that local population is potentially exposed to high cancer risk through consumption of PAH contaminated vegetables.