بررسی وضعیت فلزات سنگین در خاک، آب و گیاه اراضی سبزیکاری شاهرود

Abstract

Introduction: The arrival of toxic metals by human activities has lead to the contamination of soil. Heavy metals are among the most important pollutants in the environment. This study aimed at determining the concentration of heavy metals in soils, water and vegetables of Shhnama region in Shahroud. Methods: Vegetables studied included p arsley, leek, leaf beet, fenugreek, cress, basil, radish and the coriander. The sampling was performed during 3 months, from September to October, 2008. The collected 180 samples of vegetables, water, soil, after preparation by atomic absorption Spectrophotometers, were analyzed according to standard methods. Results: Mean concentration values of lead, cadmium, chromium, arsenic and zinc in vegetable samples were, respectively 23.99, 2.09, 5.4, 5.26, 168.4 micrograms per gram of plant tissue. Mean concentrations of heavy metals in water were, respectively, 7.55, 4.85, 0.78, 12.83 and 347.99 mg per liter in water samples. Mean concentrations of heavy metals in soil were, respectively, 81.12, 14.43, 134.32, 19.08 and 435 micrograms, per gram of soil sample. Comparing the mean concentration values for heavy metals available in vegetables, water and soil with standard values, significant differences are observed except for Zn. Concentration values of lead, cadmium, chromium and arsenic in vegetables were higher than the common values. Conclusion: The results indicate that due to the use of synthetic fertilizers, unsanitary disposal of sewage and fossil fuel combustion, water, soil and plants of the region are polluted with heavy metals.