Assessment of Heavy Metal Contamination and Health Risk Associated with Cultivated Vegetables along Dhaka-Mymensingh Highway, Bangladesh.

Abstract

The purpose of this research work is to evaluate the degree of eight heavy metals (Fe, Mn, Cu, Zn, Cd, Pb, Cr, and Ni) contamination and health risks of three regularly consumed vegetables (papaya, bottle gourd, and esculent) near one of Bangladesh's busiest roadways, the Dhaka-Mymensingh highway. The heavy metal concentrations in 45 vegetable samples were analyzed using an atomic absorption spectrometer (AAS). These samples were collected from five different sampling sites based on various land use patterns adjacent to the highway. The average concentrations (mg/kg) of Cu, Fe, Mn, Zn, Cr, and Ni were found to be 9.86, 246.8, 16.9, 28.0, 9.02, and 2.02, respectively, for papaya; 14.9, 281.2, 387.6, 49.0, 10.1, and 2.92, respectively, for bottle gourd; and 17.6, 183.4, 107.2, 80.7, 7.98, and 2.34, respectively, for esculent. The mean concentrations of Cr, Zn, and Mn in papaya, bottle gourd, and esculent were higher than the acceptable limit. Correlation analysis revealed a significant positive correlation between Fe-Cu, Zn-Fe, Cu-Fe, and Fe-Zn in papaya; Cu-Zn, Fe-Cr, Zn-Ni, and Cr-Fe in bottle gourd; and Mn-Cr, Mn-Ni, Mn-Fe, and Cr-Ni in esculent, thereby indicating their common anthropogenic sources like agricultural activities, waste from the commercial area, filling station, and vehicular emissions. Health risk assessment through target hazard quotient (THQ) revealed the highest THQ of 9.52 for Cr in bottle gourd, which poses a high non-carcinogenic health risk to the localities upon the intake of these contaminated vegetables. Target cancer risk (TCR) was found to be highest for Cr in papaya (0.013) and bottle gourd (0.014). TCR trends were found for Cr in the following order: bottle gourd > esculent > papaya. This study contributed the greatest concern for both carcinogenic and non-carcinogenic health impacts through ingesting contaminated vegetables.