بررسی میزان آرسنیک، کادمیوم و سرب در خاک و آب زیرزمینی و ارتباط آن با کود شیمیایی در خاک شالیزاری

Background and purpose: Fertilizer is one of the sources of heavy metal contamination in soil and underground water. The purpose of this study was to investigate the concentration of cadmium, lead and arsenic in paddy soil and underground water and its relationship with chemical fertilizer in Ghaemshahr City. Materials and methods: During the spring and summer in 2010, samples of soil were randomly collected from the soil (depth of 0-30cm) and the underground water 20 days before and 20 days after fertilizing. Three composite samples of three highly consumed fertilizers were also collected. After heavy metal contents (As, Cd and Pb) in soil were extracted by acid digestion method (HNO3, HCl, and H2O2), samples of water (filtration), samples of fertilizer (by acid digestion method), concentration of cadmium, lead and arsenic in water, in soil and fertilizer were measured by inductively coupled plasma-optical emission spectrometer (ICP-OES, made in Germany). Results: The results showed that heavy metal concentration in underground water was zero and it was lower than universal standards in paddy soil. However, it was found that Cd concentration in Triple Super Phosphate Fertilizer was higher than CDFA standard. The only significant relationship was observed between the amount of Potash fertilizer and cadmium concentration in the soil (P<0.05). Conclusion: Due to the highest concentration of Cd in Phosphate fertilizer, it seems that the lands that used more Potash fertilizer, the less phosphate fertilizer has been used. However, the positive relationship between the Phosphate and Potash fertilizer shows no specific reason behind it. Given that heavy metal concentration in the water was zero, no relationship was observed between the amount of heavy metals in the soil and water as well as the amount of heavy metals in the fertilizer and water.