Food Risk Assessment of Heavy Metals (Cadmium, Lead) in the Treatment Plant Effluent Due to the Consumption of Distributed Crops in Gorgan

Pollution of environment with heavy metals and its transfer to products is a global problem. The aim was to measure heavy metals in the effluent of Gorgan wastewater treatment plant which with 32 effluent samples of Gorgan wastewater treatment plant were sampled during 6 months in 2016 and concentration of lead, cadmium by polarograph and atomic absorption was assessed. Risk of carcinogenicity and non-carcinogenicity was calculated in three cases: minimum, moderate and maximum. Average concentration of lead in the effluent was 0.003943547 mg/L, which is value for cadmium measured 0.000143571 mg/L.The concentrations of heavy metals in wastewater effluent and dried sludge, except in returned sludge, were below the standards. Due to long-term use of effluents, necessity of treatment of other parameters, and effect of bioaccumulation of metals in sludge, caution should be taken for their agricultural application. Because of importance of this type of contaminants in soil and food products, continuous monitoring by water companies is highly necessary.In mean state, for every one hundred million people, 7.21 people, in max mode, for every ten million people, 1.13 people and in the case of min, for every one hundred million people, 2.82 people are at risk of cancer.