Evaluation of Heavy Metal Concentrations in Soil and Edible Vegetables Grown in Compost from Unknown Sources in Al-Jiftlik, Palestine

Abstract

The use of compost as a fertilizer has been widely used in many countries. However, compost that contains heavy metals can transfer these metals to soils and plants (vegetables). This study investigates the concentrations of metals in soil and edible vegetables that were fertilized by polluted unknown compost in Al-Jiftlik region (Palestine). The source of the compost is the autocratic dumping sites of the Israeli settlements. The compost is distributed free of charge to the Palestinian farmers. The concentrations of Ba, Cu, Pb, Th, Se, Mn, Co and As in the contaminated farms were measured. Vegetables include: Eggplant, Corn, Bell Pepper, Cucumber and Marrow. Metals availability as well as the pH, was also examined in the soil samples. Normal farms that did not use this unknown compost were used as a reference. The concentrations of Ba, Cu, Pb, Th, Se, Mn, Co and As in soil and vegetables in the polluted farms were above the WHO limits. Barium concentrations in the vegetables were ranged from 1.00 mg/kg to 0.453 mg/kg. It is high when compared to WHO limit of 0.3 mg/kg. Copper concentrations in the vegetables were ranged from 63.84 mg/kg to 50.53 mg/kg. It is high when compared to WHO limit of 40 mg/kg. Lead concentrations in the vegetables were ranged from 1.00 mg/kg to 0.453 mg/kg. Lead concentration is high when compared to WHO limit of 0.3 mg/kg. Thallium concentrations in the vegetables were ranged from 2.99 mg/kg to 1.22 mg/kg. Thallium concentration is high when compared to WHO limit of 0.3 mg/kg. Selenium concentrations in the vegetables were ranged from 0.550 mg/kg to 0.348 mg/kg. It is high when compared to WHO limit of 0.3 mg/kg. Manganese concentrations in the vegetables were ranged from 825.3 mg/kg to 446.2 mg/kg. It is almost high when compared to WHO limit of 500 mg/kg. Cobalt concentrations in the vegetables were ranged from 1.119 mg/kg to 0.522 mg/kg. Cobalt concentration is high when compared to WHO limit of 0.1 mg/kg. Arsenic concentrations in the vegetables were ranged from 4.306 mg/kg to 0.662 mg/kg. It is high when compared to WHO limit of 0.2 mg/kg. On the other hand, all metals concentrations in the clean farms were below the WHO limits. The study had recommended preventing farmers from using this unknown compost.