HUMAN HEALTH RISK ASSESSMENT OF HEAVY METALS VIA CONSUMPTION OF MARKETED VEGETABLES IN ISLAMABAD AND RAWALPINDI

Abstract

The relationship between human beings and soil is very complex. About 95% of food comes from the soil, while 99% of freshwater passes from the soil. Despite such a complex relationship, the soil has not gained much attention for ages. Soil act as a sink to many pollutants such as heavy metals (Pb, Cd, Zn, As, Cr), due to which it is much more prone to degradation. These heavy metals in soil are transferred into vegetables, through which they enter the food chain. Due to this fact, the objective of the study was set to detect the concentration of heavy metals such as Pb, Cd, Zn, As, and Cr in vegetables by using atomic absorption spectroscopy and to assess the potential health risk associated with the consumption of these contaminated vegetables using carcinogen and non-carcinogen equations. The mean concentration of Cd and Cr in all vegetables was below the permissible limit set by WHO except for tomato, while Pb and As were detected to be above the permissible limits, and Zn was below the permissible limit in all vegetables except spinach. The estimated daily intake (EDI) of all the vegetables for both adults and children was below the tolerable daily intake. The target hazard quotient (THQ) for Pb, and As, were greater than 1 showing severe health risks to both children and adults, while for Cr, Cd, and Zn, it was within safe limits (<1). Target carcinogenic risk for metals such as Pb, Cd, Cr, and As was higher than 10-6

showing potential cancer risk to both adults and children. The hazard quotient (HQ) for Pb and Cd was higher than 1 posing a health risk to both adults and children, while HQ for As and Cr was <1 for both adults and children, thus the exposed population has no risk of adverse effects. Incremental lifetime cancer risk (ILCR) for Cd, Cr, and As calculated for both children and adults were >10-5

, showing high potential cancer risk in the exposed population, while for Pb, ladyfinger, spinach, and zucchini showed high risk while others were calculated to be less than 10-5

. The study helped in the evaluation of cancer risk due to the intake of fresh vegetables marketed in Islamabad and Rawalpindi. The study concluded that the exposed population is at risk due to the consumption of vegetables contaminated with metals specifically As, Pb, Cd, and Cr. Furthermore, there is a need for regular monitoring of metal concentration in marketed fresh vegetables, and to develop advanced approaches to restrict the accumulation of metals in agricultural land.