ABSTRACT

This study assessed the physiochemical and heavy metal properties of gully erosion site in Evbhomore Community, Benin City, Edo State. Water and soil samples were collected into sterile plastic container to avoid additional contamination before taken to the laboratory for physicochemical and heavy metal analysis following standard procedures. Physicochemical characteristics of soils samples showed that clay ranged from 24.00 ± 1.92 - 36.00 ± 2.96 %, silt (24.00 ± 1.92 - 33.00 ± 2.83 %), sand (33.00 ± 2.83 - 51.00 ± 3.89 %). pH ranged from 6.70 ± 0.50 - 7.88 ± 0.93, organic matter (0.91 ± 0.37 - 2.00 ± 1.00 %), organic carbon (0.51 ± 0.25 - 0.89 ± 0.37 %) and total nitrogen (0.01 ± 0.00 - 0.05 ± 0.00 %).  Electrical conductivity ranged from 4.12 ± 1.45 - 4.81 ± 0.36 µS/cm, available phosphorus (150.00 ± 5.00 - 180.00 ± 5.74 mg/kg) and total exchangeable bases (1.60 ± 0.42 - 1.99 ± 0.69 cmol/kg). In soil samples, cadmium values ranged from 0.16±0.13 - 0.30±0.13mg/kg, Lead (1.26 ± 0.33 - 3.50 ± 0.51mg/kg), Zinc (25.12 ± 2.82 - 79.02 ± 3.29 mg/kg), Copper (27.89 ± 2.49 - 63.08 ± 3.68 mg/kg), Iron (191.16 ± 5.07 - 212.16 ± 5.92 mg/kg) and Manganese (10.80 ± 0.49 - 18.00 ± 0.81 mg/kg). Soil and land cover contributed 12% and 6% respectively to gully erosion in the study area. The occurrence of soil erosion risk in the study area has also been on the increase and is not limited to a particular area but all part causing serious land degradation affecting a wide variety of soils prone to crusting and/or piping. The widths and depths of gully erosion increased with the increase in slope gradient and decrease with increase in percentage of vegetation cover, especially during the rainy season and confirm that soil erosion in the study area has altered vegetation cover, ground slope, slope length and shape. There is therefore the need for protective strategies and measures for sensitive management of the environment to reduce erosion rates and increasing water conservation.