Occurrence of heavy metals and pesticide residues in tomato crop: a threat to public health

The presence of heavy metals and pesticide residues in higher concentrations in irrigation water and crops are two major concerns in developing and underdeveloped countries. The assessment and monitoring of these environmental contaminants in fruit and vegetables are vital for effective management and consumers’ health. In the current study, the presence of heavy metals and pesticides in irrigation water (sewage and tube well), soil, and tomato crop (grown on these water sources and sprayed with different pesticides in various locations of Peshawar city) was determined. Sewage water exhibited a significantly (p > 0.05) higher pH, total dissolved solid (TDS), and electrical conductivity (EC) when compared with the optimum limits as recommended by the World Health Organization (WHO). In addition, the concentrations of heavy metals, i.e., Cd, Pb, Ni, Cu, Zn, and Fe, were also significantly (p > 0.05) higher in this source. Furthermore, the analysis of sewage irrigated soil and various parts of tomato plants grown on this soil revealed a higher concentration of heavy metals compared with the standard limit set by WHO. Similarly, the levels of pesticide residues of chlorpyrifos and emamectin were significantly (p > 0.05) higher in tomato fruits and leaves and soil samples when compared with the standard limits set by the European Union. The current study provides first ever insight into the presence and levels of toxic heavy metals and pesticide residues in tomato crops grown on sewage water in Peshawar city for the effective monitoring and management of these health hazards.