ABSTRACT
Soil degradation is gradually becoming prominent in Nigeria. Therefore this study investigated the characteristic of the physicochemical parameters of soils at Nworie River bank in order to access the impact of sand dredging on nearby soils. Seventeen soil samples were collected using hand auger at depth ranging from 0-15 cm and 15-30 cm for top and subsurface soil respectively from dredging site,control samples were collected at upstream of the river bank at about 6km away from the dredging site. The samples were labeled in a polythene bag and sent to the laboratory within 24hours for analysis methods used are: hydrometer, titration, bray and kurtz method, marco-kjedahl , distillation procedure and Atomic Absorption Spectrometer . Results are as follows Sand ranges from (73.2-93.2% ),Silt(2.0-4.0%),organic carbon(0.02-0.26%),organic matter (0.03-0.49%) total nitrogen (0.01-0.02%),available phosphorus (0.20-4.50%),total exchangeable acid (0.1 -0.445 meq/100g),total exchangeable bases (0.065 -0.219meq/100g),pH (4.64-6.21),pH(Kcl) (0.4-1.0),lead(0.52-1.02 mg/kg),zinc (11.11-14.4 mg/kg),nickel (2.01-3.14 mg/kg),cadmium(not detected) ,copper(not detected), iron (36.18 - 68.00 mg/kg) . Analysis of variance was significant with a P-Value of 0.12 at confidence level of 0.05. From the of study , the effect of sand excavation in the soil's physical and chemical properties of Nworie bank soils was observed mainly in Organic Carbon, Organic Matter, Total Nitrogen which were found to be very low which implied a deficit in soils nutrients in microbial activities . Also TEB (Total Exchangeable Bases) was found to be very low which has a negative consequence. The investigation has clearly shown that the heavy metals increase over time .Fe was considerably high Mn , Ni, Pb were present while others like Cu and Cd were not detected in soils at dredging site of Nworie River bank. Therefore to manage degradation of soils; assessment should be done to predict possible environmental impacts and encourage public participation at the decision level, whilst management is used to implement plans to prevent or minimize negative impacts.
