Environmental impact of elemental concentration and distribution in waters, soils and plants along the Lokoja-Abuja pipeline routes of Bida Basin, northwestern Nigeria

摘要

This paper presents environmental study carried out to evaluate the impacts of elements' concentrations in water, soil, plants and the level of environmental damage. This is to establish the rate of pollution and degree of enrichment to enhance delineation of highly polluted areas along the pipeline routes. It was achieved by determining their spatial distribution, concentration and/or occurrences as well as the possible sources of enrichment. Forty-six (46) surface water samples were collected during the dry season while thirty (30) surface water samples were collected in the wet season respectively. The sampling was systematically carried out at diverse locations along the streams and major rivers to broadly cover the variation in the area. Fifty-one (51) soil samples were collected during dry and wet seasons to determine the texture, heavy metal concentration and physico-chemical characteristics. Thirty (30) and twenty-six (26) samples of stream and river sediments were also collected during the dry and wet seasons for physico-chemical characterization, texture and heavy metal concentrations. Ten plant tissues were collected and analysed to ascertain the rate of absorption. The results of the surface water during the dry and wet seasons showed slight acidity while the Electrical Conductivity revealed that the major ions are higher in the dry season. The major anions and cations accounted for about 71% and 29% of the Total Dissolved Solids respectively. The higher concentrations of Fe in the stream sediments and soil than that in the water and plant tissues suggest the weathering of oolitic, pisolitic and argillaceous ironstone within the area. Concentration of NH_4 emanate from anthropogenic sources Textural classification revealed sand dominated soil which confirmed that the soil and stream sediment are autochthonous. The concentration of heavy metals and cations for both seasons in the plant tissues showed no discrepancy. The hydro-chemical facies characterization of the surface water identified two water groups of Ca-HCO_3 and Na-K-Cl. The water chemistry evolution in this area is controlled domi-nantly by weathering and precipitation in the wet season. There is strong soil-plant relationship which is evident in their enrichment. Heavy metal distribution is generally within the acceptable limit except for few locations where Pb, Zn and Fe are of high concentration.