Determination of Heavy Metals Pollution in Grass and Soil along Major Highways in Kano

Abstract

Pollution caused by traffic activities is increasingly becoming a great threat to urban environmental quality and human health in many cities of the world. Therefore, in this study grass (Paspalum Orbiculare) and soil samples were collected from four major highways in Kano, at distance interval of 1, 2, 3, 4 and 5 meters away from the edge of the road. The samples were analyzed for Cu, Ni and Cr using Atomic Absorption Spectrophotometer (AAS). The levels of Cu, Ni and Cr in grass were found to be 3.20±0.84 - 4.60±0.55µg/g, 5.20±1.79 -6.40±1.82µg/g and 1.20±0.57 - 3.00±0.79µg/g dry weight respectively. The ranges of concentrations in soil were from 1.80±0.84 - 2.60±1.14µg/g, 2.20±0.84 - 3.20±1.30µg/g and 0.90±0.42 - 1.30±0.82µg/g dry weight for Cu, Ni and Cr respectively. Heavy metals in the four major roads were significantly higher (P < 0.05) than those on the reference site. The results showed that the levels of Ni and Cr exceeded the EU limit levels (0.20 - 5.00-µg/g for Ni and 0.02µg/g -0.50µg/g for Cr) and signify that metal dynamics up the food chain is highly possible.