Telfairia Occidentalis Leaf Concentrations of Hg, Pb and Cd Planted in Old Sewage Sludge Dumpsites in Owerri Imo State

Abstract

Leaves of Telfairia OCCIDENTALIS planted in abandoned Sewage Dumpsite were analyzed for mercury Hg, Lead Pb and Cadmium Cd levels. Samples were collected from three dump areas at a depth of 0-30cm, and fallow lands of about 50 meters away from the dumps were also sampled for reference. The samples were subjected to analysis and Heavy metals were determined using Atomic Absorption Spectrophotometer (AAS). The findings indicated that sewage increased the soil concentrations of Heavy Metals (0.19 Hg, 17.0 Pb, and 3.0 Cd Mg/Kg1) when compared with control (0.04 Hg, 1.4 Pb, and 0.29 Cd Mg/Kg1). These were not high when compared with established permissible limits according to FEPA WHO. These concentrations were not high to cause health challenges. Many scientist reported that not all sewage sludge contains high amount of heavy metals especially when allowed to decompose for a longer period of 4 years even without prior treatment, but repeated application can increase levels. Sewage Sludge also increased N, P, K, Ca, Mg, K and ECEC and this may triggered the reason of continuous planting by farmers in dumpsites due to the fact that sewage sludge can increase the nutrient content of soil and improves its physical and chemical properties. Organic matter content which is also of great importance in soil reaction was increased by the sewage sludge deposit. The deposit of sewage sludge added organic matter, improved the soil physical and chemical properties, at the same time increased the heavy metals levels. But the heavy metals levels were not above permissible limits for heavy metal concentrations in soils. It is therefore recommended to land spray the sludge and allowed to decompose for about 2 years before planting on it. The result was discussed in-line with heavy metals in questions and permissible limits for each.