Distribution of some heavy metals in the soil-clay-silt particle fractions of refuse dumpsites in Enugu State

Abstract

The indiscriminate use of open land as dumpsites in Nigeria without appropriate measures to prevent environmental hazards has resulted in the contamination of soil and the exposure of human populations to environmental and health hazards. Soil is a part of the environment that receives pollutant from all types of human activities. Heavy metals originating from various organic waste sources and industrial activities accumulate in the soil and their accumulations depend on the amount and types of waste applied and also on the soil properties as soils differ in their ability to retain nutrient elements. This research was carried out to investigate distribution of some heavy metals in the soil-clay-silt particle fractions of refuse dumpsites in Enugu state. Soil samples were collected from the vicinity of the dumpsites from two locations – Ugwuaji (along Enugu-Port Harcourt Express Way) and Nsukka central town, at predetermined depth intervals of 0-20cm, 20-40cm and 40-60cm. The result of samples analysed showed that heavy metal concentration at both locations was far below the critical limits. The clay fraction retained more heavy metals (Zn, B, Cd and Mn) and prevented them from leaching into the ground water especially in 0-20cm and 20-40cm depth than the silt fraction. This implies that dumpsites should be sited in soils that are high in clay content than in silt content to prevent ground water pollutions by heavy metal through leaching.

Key words: distribution, heavy metals, clay-silt fraction, dumpsites.