عنوان مقاله [English]
Environmental pollution caused by heavy metals is a global concern. The main source of heavy metals in soil is the urban and industrial wastewater, synthetic phosphate fertilizers, sewage sludge, and metal extraction mines. The level of heavy metals absorption in plants not only depends on the concentration of the metals and the physical and chemical composition of the soil, but also varies in different parts of each plant. The main objective of this study was analyzing the impact of various levels of Cadmium concentration in soil and EDTA in irrigation water on its absorption and accumulation in various parts of five cucurbit types. The experiments were carried out under laboratory conditions, using the factorial in randomized blocks design by five treatments and three repetitions. The treatments included the Cd concentration in 4 levels (i.e. soil without adding Cd as control treatment, soil with 50 mg kg-1 Cd, soil with 50 mg kg-1 Cd and irrigation water with 0.5 molar EDTA, and soil with 100 mgkg-1 Cd and irrigation water with 0.5 molar EDTA). The results showed that the level of Cadmium accumulation in the plant species is in direct proportion to the level of Cadmium concentration in soil. Adding EDTA to the irrigation water (third and fourth treatments) effectively increased the amount of Cadmium absorption and accumulation in plants. All plant specimens showed significant increases in the rate of absorption and amount of Cadmium accumulation compared to the second treatment. The increase was recorded as 53% in root, 122% in leaf, 31% in stem, and 27% in root. The results also showed that in all treatments except the control treatment Cadmium accumulation is in excess of permissible limits for human consumptions.