Quality of Water for Irrigating Urban Vegetable Farms: An assessment of Toxic and Essential Metals in Water from an Urban Lake

Abstract

In order to advise farmers as to which source of water will be best to draw from for irrigation in order to avoid or minimize the potential of the risk of heavy metal contamination of their vegetables, this study determined the concentrations of selected heavy metals and some physicochemical indicators of the quality of water from along the bank of the Marina Park Lake, which we recollected according to the guidelines of the American Public Health Association. Metals were analysed for with an Atomic Absorption Spectrophotometer and the concentration of the detected metals were within the ranges of 0.628 to 1.816 mg/L for Fe, <0.002 to 0.051 mg/L for Mn, 0.019 to 0.025 mg/L for Zn, 0.024 to 0.033 mg/L for As) and <0.001 to 0.004 mg/L forHg, all of which were less than the FAO recommended max concentrations of elements in water 1 for irrigation. Cu, Pd, Cd, Co and Cr were below detection limits. Generally, water from the Marina-Park Lake was suitable, in respect of heavy metal concentrations, for the irrigation of vegetable farms, and specifically 2 was the most suitable site to draw water for this purpose.