Assessment of lead toxicity in diverse irrigation regimes and potential health implications of agriculturally grown crops in Pakistan

In many countries, where wastewater irrigation has become a common practice, the accumulation of heavy metals by crops has been regarded as a severe environmental hazard. The evaluation of the toxic element lead (Pb) in water, agricultural soils and food crops, and their potential damage to human health, is the focus of the present study. Samples of eleven food crops, soil, with three treatments, waste, canal, and tube well waters, were collected from three feeding sites, Sargodha city, Sahiwal, Shahpur, and evaluated for Pb concentration. The results indicates that the range of Pb in the water, soil and crop samples were from 0.023 to 0.039 mg/L, 2.932-13.687 mg/kg and 1.241-4.825 mg/kg, respectively. The metal concentration was significantly higher (P < 0.001) in wastewater treated soil and crop samples that exceed the permissible limit of the World Health Organization (WHO). There is a positive correlation between the Pb concentration in the soil and crop samples. The pollution load index and enrichment factor are greater than 1, indicating a high level of soil contamination and the influence of natural and anthropogenic sources of Pb metal accumulation in soils. The bioconcentration factor (BCF), daily intake of metal (DIM), health risk index (HRI) and metal values are less than 1, indicating that toxic Pb are present in lower quantities in food crops and had no health risks to consumers. In wastewater treated soils, there is a significant accumulation of Pb toxicity. Therefore, it is vitally important to address Pb contamination and its potential entrance mute into the human food chain.