The fate of Heavy Metals in Vegetables Irrigated with Raw Wastewater in Palestine: A Case Study of Al-Far’a Area
Mahmoud Khader Abed Driaat
محمود خضر عبد دريعات
Wastewater, and industrial wastewater, is known to be a major source of pollution with heavy metals. The discharge of raw wastewater to the environment without any advance treatment creates the potential for heavy metals contamination to the nearby agricultural lands. Root and fruit vegetables are important kinds of vegetables in the human food diet. These kind of vegetables are rich in vitamins and nutrients. However, root and fruit vegetables should not contain heavy metals over a range of concentrations, which could pose potential health risk to the consumers. Contamination with heavy metals is considered an environmental threat, as these metals are toxic even at low concentrations. This study was conducted to determine heavy metals concentration in root and fruit vegetables in the central Jordan Valley region in Palestine, which includes Nablus east, and Al-Jiftlik village in the West Bank. Thus, vegetable samples, particularly Potato, Zucchini, Eggplants, and Onions, had been collected from different farms, and analysed for different heavy metals (Fe, Pb, Cr, Co, Cd, Mn, Ni, V, and Ba) by using ICP-MS. For some samples, the results were found to be exceeding WHO/FAO permissible limit for human consumption, while other samples were found to be within the safe allowable limit. Cr was found to be the highest in concentration while Mn, Co, Ni, Fe, and Cd were the lowest. Ba and V concentrations varied between high in some samples and low in other, then comes Pb that showed a concertation close to the safe limit of the (WHO). Soil samples in addition to water samples had been also analysed for their content of heavy metals in order to correlate the environmental factors to heavy metal contamination. However, most of concentrations were below the limit set by WHO/FAO and it was hard to build a relationship of soil/water to plant transfer of heavy metals. It was noticed that the Ni, Mn, Co, as an essential elements were found to be very low concentrations in soil, and water samples, and thus their concentration were low in most of the vegetables samples. Cd showed a very low concentration, Cd was very low and even below the detection levels in some of water/soil and vegetables samples. Pb was very low in most of the soil/water samples, while the concentration of Pb in the vegetable samples were little below the permission level, which suggest that even at a low concentration of Pb in soil/water system, the vegetables were able to accumulate Pb in their fruits. Thus it was concluded that the contamination found in the root samples and fruit samples vegetables samples was related to the contamination caused by the discharge of raw wastewater to the environment as the case of Wadi Al-Bathan in Al-Fra' catchment in the central Jordan Valley.