Stream Sediments Investigation of Heavy Metals at Nasarawa State University Keffi, Part of Keffi Sheet 208 NE, Central Nigeria

Stream sediments investigation was carried out at Nasarawa State University Keffi and its environs, part of Keffi Sheet 208 NE, Central Nigeria. The Basement Complex rocks of the area consist of biotite gneiss, granitic gneiss and schist. Structures such as joints, veins and foliations were observed, trending mostly in NE-SW and NNW-SSE directions. Fifteen (15) stream sediments were sampled systematically (500 m interval) at a depth of 15cm along three (3) stream channels and analysed for heavy metals. Results obtained revealed the following trend of ranges: Fe 20.44-318.17 mg/l, Cu 0.02-0.24 mg/l, Zn 0.06-1.13 mg/l, As 0.00-1.81 mg/l and Pb 0.00-0.58 mg/l; with mean values of 156.58 mg/l, 0.10 mg/l, 0.30 mg/l, 0.37 mg/l and 0.19 mg/l respectively. The high relative abundance of Fe, Zn, Pb, Cu and As in the soil could be due to weathering of the host or underlying rocks. Also, these metals could be leached from the soil and other anthropogenic sources which could include; indiscriminate disposal of chemicals/waste water around the Entrepreneurship Development Centre (EDC), sewage sludge emanating from the old cotton company located in Angwan Lambu, chemicals from the fertilizer warehouse in Angwan Lambu and farms located uphill. The dominance of heavy metals in the sediments samples is in an order of Fe>Zn>As>Cu>Pb, Fe>As>Zn>Cu>Pb and Fe>Pb>Zn>Cu along the channels of stream 1, 2 and 3 respectively