ارزيابي شاخص هاي خطرپذيري فلزات سنگين ناشي از مصرف سبزيجات شهرستان ورامين

Assessing Heavy Metals Risk Indices Caused by Vegetable Consumption in Varamin city

سابقه و هدف: تجمع فلزات سنگين در خاك‌هاي كشاورزي، علاوه بر آلودگي محيط زيست موجب افزايش غلظت و جذب فلزات سنگين در گياهان مي‌شود. مصرف روزانه محصولات كشاورزي مهمترين مسير مواجهه انسان با آلاينده‌ها و بيماري‌هاي مختلف است. هدف از اين مطالعه تعيين غلظت برخي از فلزات سنگين در سبزيجات و گياهان رايج در بخشي از اراضي كشاورزي شهرستان ورامين در استان تهران و ارزيـابي ميزان خطر زيست‌محيطي عناصر سـنگين با اسـتفاده از ضرائب خطرپذيري(HQs) مرتبط با سلامت انسان است. مواد و روش‌ها: نمونه‌برداري مركب از سبزيجات ريحان، شاهي، تربچه، تره، نعناع، جعفري، چغندر، مرزه و همچنين گياهان ذرت و برنج در منطقه‌اي با وسعت 50 هكتار در سه تكرار به‌صورت تصادفي انجام شد. نمونه‌ها پس از آماده‌سازي به روش هضم خشك آماده سازي و اندازه گيري شد و غلظت كادميوم، سرب، روي، مس، كروم، كبالت و نيكل با استفاده از دستگاه جذب اتمي تعيين گرديد. سپس فاكتور تجمع زيستي، فاكتور انتقال، دريافت روزانه و شاخص‌هاي خطرپذيري فلزات سنگين براي انسان محاسبه شد. يافته‌ها: بيشترين غلظت روي، مس، سرب، كادميوم، كبالت، كروم و نيكل به ترتيب در گياه شاهي (12/54)، نعناع (3/3)، نعناع (1)، تربچه (0/22)، ريحان (0/48)، تره (0/70) و ذرت (1/24 ميلي‌گرم بر كيلوگرم ماده خشك) مشاهده گرديد. فاكتور انتقال عناصر سرب در شاهي، كادميوم در جعفري، روي در چغندر، كبالت، كروم و سرب در تربچه و كروم در مرزه بيشتر از يك بود (1

Background and objectives: Excessive accumulation of heavy metals in agricultural soils, not only leads to environmental pollution but also increases the absorption of heavy metals by plants. Food consumption had been identified as the major path way of human exposure. The purpose of this study was to determine the concentration of some heavy metals in common vegetables and plants in the region in a part of the agricultural land of Varamin in Tehran province and assess the environmental risk of heavy metals using human health indices. Materials and methods: The composite sampling of basil, garden cress, radish, chives, mint, parsley, chard, and savory, as well as corn and rice in a region of 50 hectares with three replications was done randomly. Samples were prepared by dry digestion method and cadmium, lead, zinc, copper, chromium, cobalt and nickel concentrations were determined using atomic absorption spectrometry. Following the results of the experiment, the bioaccumulation factor (BCF), Translocation Factor (TF), average daily intake index (EDI), and Health index (THQ, TDHQ and HI) were calculated. Results: The highest average concentration of zinc, copper, lead, cadmium, cobalt, chromium and nickel was found in garden cress (12.54), mint (3.3), mint (1), radish (0.22) basil (0.48), chives (0.70) and corn (1.24 mg/kg dry matter) were observed. The translocation factor (TF) of lead in garden cress, cadmium in parsley, zinc in chard, cobalt, chromium, and lead in radish and chromium in savory were more than 1. In contrast, transfer factor (TF) values for rice, corn and oats were less than 1 for all the heavy elements. The bioaccumulation factor (BCF) of cobalt in peppermint, and cadmium for chard, and savory were more than one, and for other plants, the amount of this factor for the metal studied was less than one. Cadmium, cobalt, copper, nickel, zinc and lead in rice plant in adults (0.062, 0.029, 0.110, 0.225, 0.052, 0.193) and in children (0.061, 0.008, 0.096, 0.020, 0.050 and 0.149 have the highest risk of non-cancerous diseases (HQ) for residents of the region. The Target hazard quotient (THQ) in both age groups was reduced as follows: (Corn Sugar, Mint, Basil, Rice, Parsley, Radish and Rice) and in a healthy range. Conclusion: The value of Target diet Hazard Quotient (TDHQ) was less than one, indicating the absence of risk of non-cancerous diseases for consumers due to the consumption of 10 examined products in accordance with Iran's national consumption patterns. Lead in the children's age group showed the highest TDHQ (0.300), indicating a higher risk of lead risk in the total consumption of products than other elements. Overall, the results showed the total health index (HI) of heavy elements for each of the studied age groups was less than 1, indicating that the residents in the study area are in a safe condition.