INVESTIGATION OF HEAVY METALS AND ASSOCIATED HEALTH RISKS IN SOME SWAMPY AGRICULTURAL SOILS OF NASARAWA WEST, NIGERIA

Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of food chain. The study investigated heavy metals with specific emphasis on the health risk assessment in some swampy agricultural soils in Nasarawa West, Nigeria. Fifty soil samples were collected from five Local Government Areas. Karu, Keffi, Kokona, Nasarawa and Toto. Indicating ten soil samples from each Local Government Areas. The samples were collected at thirty centimeter depth from the top soil and the coordinate points were recorded using Global Positioning System. They soils were dried under ambient temperature. Agate Pestle and Mortar was used to pulverize the soils into fine particles and allowed to pass through 2.0mm sieve, and subjected to X-Ray Florescence Spectroscopy Analysis at Center for Energy Research and Development. Obafemi Awololowo University, Ile Ife. The results revealed the following heavy metals As, Cd, Cr, Cu, Ni, Pb and Zn. Ingestion, inhalation and dermal contact of food grown from heavy metal contaminated soils pose potential human health risk. The hazard index (HI) for all the pathways for adult was equal to 26.61. A value much greater than one (>1) due to dermal pathway and for children was 0.04. A value less than one due to inhalation pathway. This makes non-carcinogenic effects significant to the adult population. The total excess life cancer risk for Karu and Keffi (1.3x108, 1.1x109) was found to be higher than acceptable values of United State (1.0x10-4 to 1.0x10-6 ) and South Africa (5.0x10-6). However, Kokona, Nasarawa and Toto (2.1x10-3, 3.0x10-3 and 6.4x10-3) respectively were found to be below the reference value. This implies that there is a probability that one adult in 10,000 may be affected in Karu and Toto. Remediation measures and techniques should be employ by the appropriate authority (Government) at all levels so as to formulate polices and to reduce significant heavy metal concentration levels in soils for agricultural production.