Depth Profile of Anthropogenic Pollutants in Some Arable Lands in Plateau State

Abstract

A depth profile approach was applied to twenty-five (25) soil samples collected from five different villages in plateau state to assess the environmental accumulation of possible anthropogenic pollutants. Depth wise collection was adapted from the top soil (0-5cm) to the deep soil (20-25cm). Walkley Black titration method was used to obtained organic matter content and Nitrogen. Bouyoucos method for particle size determination, and Phosphorus was by Bray P-1 method. AAS was used to determine Mn, Zn, Cu, and Fe while Na and K were by AES. The results indicated that the top soil (0-10cm) contained a higher amount of organic matter which ranges from (0-18%). These values decreased as the depth increased from the mid soil (10-20cm) to the deep soil (20-25cm). Values ranged from 0-4.9 and 2.2mg/g. Elemental concentrations also generally decreased as the depth increased. The maximum measured values were Mn 830µg/g (0-5cm), Cu 30µg/g (15-20cm), Zn 200µg/g (0-5cm), Na 1590µg/g (0-5cm), K 1140µg/g 0-5cm) and Fe 770µg/g (0-5cm). This indicates high surface soil elemental content which decreases as the depth increases. The profile (0-5cm) indicates the anthropogenic additions while that of (15-25cm) showed the natural additions. Metal concentrations also decreases as the organic matter decreased. In this area, clay was not an important agent in holding the metals in place because of the low percentage of clay recorded. The highest value was 8.8% for 5-10cm depth; insoluble organic matter was more significant in this case.