Assessment of Heavy Metals in Lettuce Grown in Soils Irrigated with Different Water Sources in the Accra Metropolis

This study was carried out to assess the levels of different heavy metals like Iron, Manganese, Copper, Zinc, Cadmium and Lead in three different irrigation water sources, irrigated soils and irrigated lettuce. The result indicates positive and significant correlation of heavy metals concentrations between the irrigation water, irrigated soils and irrigated lettuce. The range of various heavy metals in drained water irrigated lettuce was 162.00-190.00, 60.25-78.25, 6.03-8.80 and 23.88-52.00 mg/kg in Fe, Mn, Cu and Zn, respectively. Generally, mean heavy metal concentrations of the water, soil and lettuce from two vegetable growing sites were within the FAO/WHO recommended maximum concentrations for crop production. Although the levels of heavy metals in the irrigation water, irrigated soils and irrigated lettuce were below the recommended limits, regular monitoring of these metal levels from these sources is essential to prevent excessive heavy metal buildup in vegetables in general.