ارزیابی آلودگی و ارتباط بین غلظت فلزات سنگین در خاک و سبزی‌جات برگی استان زنجان

نوع مقاله : مقاله پژوهشی

10.22092/ijsr.2016.106319

چکیده

استفاده از فاضلاب شهری برای چندین سال گذشته در نواحی مشخص (اطراف راه­آهن) و مجاورت مزارع، به کارخانه­جات فرآوری سرب و روی، منجر­به تجمع فلزات سنگین درخاک و سبزی­جات شده است. در این تحقیق، غلظت فلزات سنگین (مس، روی، کادمیم و سرب) در بعضی از سبزیجات (گشنیز، ریحان، شوید، نعناع، مرزه، تره، برگ چغندر، شنبلیله و جعفری) در 6 منطقه شهر زنجان مورد ارزیابی قرار گرفتند. نتایج نشان داد که، بیشترین غلظت فلزات سنگین در نمونه خاک­های تحت آبیاری با فاضلاب بوده که از اطراف راه­آهن جمع­آوری شدند. از بین فلزات سنگین، حداکثر غلظت مس گیاهی، در مزارع آبیاری با فاضلاب بودند. غلظت کادمیم، روی و سرب در همه سبزیجات مورد مطالعه، بالاتر از محدوده ایمن برای مصرف انسان بود. بیشترین آلودگی کادمیم و روی در نمونه های مرزه (به ترتیب، 8/1 و 3/157 میلی­گرم در کیلوگرم وزن­خشک) و برای سرب و مس در سبزی نعناع (به ترتیب، 5/7 و 3/18 میلی­گرم در کیلوگرم وزن­خشک) به­دست آمد که برای مصرف انسان، بالاتر از محدوده قابل قبول استاندارد ملی ایران بودند. میزان دریافت قابل تحمل روزانه موقتی برای کادمیم و سرب، کمتر ازاستاندارد ملی ایران بود. بنابراین، استفاده طولانی مدت و مصرف بالای سبزیجات (بیش­تر از 058/0کیلوگرم روزانه) در استان زنجان، می­تواند عواقب خطرناکی بر سلامتی انسان داشته باشد. از طرفی، تنها، غلظت مس خاک، همبستگی مثبت معنی­دار با غلظت مس سبزیجات نعناع و ریحان نشان داد. بنابراین با توجه به آلودگی سبزیجات مزارع مجاور به کارخانه سرب و روی، می­توان چنین استنباط کرد که، منبع اصلی تجمع فلزات سنگین در سبزیجات برگی، آلودگی جوی حاصل از مجاورت به کارخانه صنعتی (سرب و روی) می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Assessment of Pollution and Relationship between Heavy Metals Concentration in Soil and Leafy Vegetables in Zanjan Province

چکیده [English]

In recent years, the use of municipal sewage in certain areas in Zanjan city, Iran, and farms adjacent to Zn and Pb processing plants has led to accumulation of heavy metals in the soil and vegetables. In this research, the concentrations of heavy metals (Cu, Zn, Cd and Pb) in some vegetables (coriander, basil, dill, mint, savory, leek, chard, fenugreek and parsley) cultivated in six regions of Zanjan city were assessed. Results indicated that the highest concentration of heavy metals was in wastewater-irrigated soils, located around the railway. Among the studied heavy metals, Cu concentration of vegetables was higher in wastewater-irrigated farms. Concentrations of Cd, Zn, and Pb exceeded the safe limits for human consumption in all of the vegetables. The highest contaminations of Cd and Zn were found in savory samples (1.8 and 157.3 mg/kg fresh weight, respectively) and for Pb and Cu in mint (7.5 and 18.3 mg/kg fresh weight, respectively) which were higher than the Institute of Standards and Industrial Research of Iran (ISIRI) permissible values for human consumption. Provisional tolerable daily intake (PTDI) for Cd and Pb was less than ISIRI values. Therefore, long-term use of high intake of vegetables (higher than 0.058 kg/day) may have dangerous consequences on human health in Zanjan Province. However, the soil Cu concentrations showed positive significant correlation with Cu in mint (p < 0.01) and basil (p < 0.05). Therefore, considering the contamination of vegetables in farms adjacent to Pb and Zn processing plants, it can be concluded that the major source of heavy metals accumulation in leafy vegetables was airborne pollution due to proximity to these industrial plants.

کلیدواژه‌ها [English]

  • Contaminated vegetables
  • Soil contamination
  • Cadmium
  • Lead
  • COPPER
  • Zinc
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