The accumulation of heavy metals by crops irrigated with wastewater has been considered as a serious environmental problem in many developing countries, where the wastewater irrigation has emerged as a common practice. In this research, we were concerned with the highly toxic metal lead (Pb) in water, agricultural soils, and wheat crops, and the possible risk on human health in the peripheral agricultural regions of Punjab, Pakistan. Various types of irrigated water (ground, sewage, industrial), soil, and wheat plant (root, shoot, grain) samples of five different varieties (Seher-2006, Punjab-2011, Faislabad-2008, Watan, and Galaxy-2013) were collected from seven different districts and then pooled up to make one composite sample and analyzed for Cd concentration. The various pollution and mobility indices (pollution load index, enrichment factor, daily intake of metal, health risk index, translocation factor, bioaccumulation factor, and bio-concentration factor) were also calculated. The descending order for Pb concentration was as follows: water>soil>wheat plant. The range of concentration of Pb in all types of water, soil, and wheat plant (root, shoot, grains) samples was (7.05-7.83 mg/l), (6.32-7.74 mg/kg), (3.23-4.82, 1.14-2.75, 0.09-0.51 mg/kg), respectively. The concentration of Pb in all types of water samples exceeded the maximum permissible limit. There were values found to be < 1.00 in all the pollution and mobility indices for all types of samples. These results reveal that high levels of Pb in irrigated water may pollute the soil and wheat plants of these regions in the near future, if various control measures have not been taken. It may pose a great health risk to the local human and animal populations. Preventive measures should be taken to reduce heavy metal pollution of irrigation water and soils to protect both human and animal health in various regions of Punjab, Pakistan.
Keywords: Bio-concentration factor; Lead; Mobility indices; Pollution load index.