Impact of soil types and petroleum effluents on the earthworm, Eudrilus eugeniae.

Earthworm, Eudrilus eugeniae, exposed to different concentrations of dump-site soil and petroleum effluents exhibited different morbidity and mortality responses. Lake sediments caused varied fluctuations in weight over a 20 day exposure period. Colour changes and mortality up to 15% were observed in earthworms cultured in 100% lake sediment, while weight loss, coiling and sluggish movement were observed in 50% lake water. The effects of 100% dump-site soils were more pronounced as 40% death, swelling, body lesions, stiffening, coiling and low reproduction were recorded. Earthworms were useful as an organism in testing the toxicity of dump-site soils and effluent from a petroleum industry. Dump-site soils and soils polluted with petroleum effluent reduced populations of earthworms and this could subsequently affect other components of the ecosystems associated with earthworm activities.

Accumulation of lead, cadmium and chromium in some plants cultivated along the bank of river Ribila at Odo-nla area of Ikorodu, Lagos state, Nigeria.

Heavy metal in soil samples and in washed and unwashed samples of Telfaria occidentalis (ugwu) and Talinum triangulare (waterleaf) cultivated on the bank of river Ribila in Odo-nla village were determined. The soil was moderately polluted with cadmium when compared with Federal Environmental Protection Agency standards. The difference between the unwashed and washed plant samples revealed that metal pollutants exist as superficial contaminants on the foliage surface which is the edible portion and if the foliage portion is washed thoroughly it may be safe for dietary consumption. There is no doubt that continuous discharge of effluent and gaseous emissions from the industries located in this area and dumping of domestic wastes into the river may lead to higher concentrations of these heavy metals in the soil and in the tissue of the leafy vegetables cultivated on the river bank over time. This can eventually lead to pollution of the soil and the cultivated plants, which are ready source of food for the people and other organisms in the food chain.