Assessment of heavy metal contents of Lycopersicum esculentum mill. (tomato) and Capsicum chinense l. (pepper) irrigated with treated and untreated detergent and soap wastewaters

Tomato and pepper are staple and common vegetables consumed by all classes of Nigerian populace. Due to high consumption rate of these vegetables, they are cultivated all year round in many localities including the peri-urban cities. The problem of freshwater scarcity in peri-urban cities and the northern part of Nigeria has made peasant farmers in these areas to resolve to the use of wastewaters for irrigation with no knowledge of their status and safety. Therefore, the level of heavy metal contents in Lycopersicum esculentum and Capsicum chinense grown in the Screen House of the University of Ilorin, North-central Nigeria were studied using treated and untreated detergent and soap wastewaters. Fallowed soils collected from the University Botanical Garden, homogenized and packed into planting bags were used for the experiment. Viable seeds of Lycopersicum esculentum and Capsicum chinense were sown in 10 planting bags for each crop and irrigated with 0%, 5%, 10%, 20% and 40% Treated and Untreated wastewaters. After 12WAP, leaf samples of Lycopersicum esculentum and Capsicum chinense were collected, air-dried, digested and the digests were analyzed for Manganese (Mn), Copper (Cu), Chromium (Cr), Lead (Pb) and Cadmium (Cd) by Atomic Absorption Spectrophotometry. It was evident that there was prevalence of heavy metals in the wastewaters particularly the untreated wastewater and the content of the heavy metals were concentration-dependent in the leaves of the test crops. It is therefore imperative to inform and enlighten the local farmers and the consumers on the danger of using such water for irrigation of agricultural crops in order to ensure safety.