Impact of Irrigating Vegetables With Water From a Stream Receiving Leachate From an As2o3 Polluted Cattle Dip Site in Zimbabwe.

Abstract

Abstract The levels of arsenic (As) and other carcinogenic elements (Be, Cd, Cr, Co and Ni), and toxic elements (Hg and Pb) in vegetables grown in riverbank gardens irrigated with water from a stream receiving leachate from a polluted site around a cattle dip historically based on AS2O3 as dip chemical, were determined using ICP-MS. Furthermore, the distribution and concentration of these metals in the garden soils and stream water were also measured, and a correlational analysis carried out. The data presented shows that the levels of As at 9±0.14 to 22±0.1 µg/kg, 3.15±0.0.07 to 12.1±0.28 µg/L, and 9.7±0.14 to 39.37 µg/kg, as well as other carcinogenic and/or toxic elements (Be, Cd, Cr, Co, Ni, Hg and Pb), fall within the permissible limits set by the WHO/FAO for food, irrigation water and soil respectively. However, the levels of Co in vegetable samples, and those of Ni and Pb in the river water, were above the set permissible limits. In addition, correlation data showed that irrigating the garden soils with the stream water had little or no effect on the concentration of AS in the garden soils and the vegetable grown in the garden soils, but resulted in a slight increase in the concentration of Co in the garden soils as well as the vegetables. Other possible sources of pollution of the garden soils by AS, other than the stream water used for irrigation, are discussed.