Omwoma S., Lalah J.O., Ongeri D.M.K., Wanyonyi M.B.
Department of Chemistry, Maseno University, P.O. Box 333, Maseno 40105, Kenya
Omwoma, S., Department of Chemistry, Maseno University, P.O. Box 333, Maseno 40105, Kenya; Lalah, J.O.; Ongeri, D.M.K., Department of Chemistry, Maseno University, P.O. Box 333, Maseno 40105, Kenya; Wanyonyi, M.B., Department of Chemistry, Maseno University, P.O. Box 333, Maseno 40105, Kenya
Analysis of heavy metals in top soil samples from Nzoia sugarcane farms in Western Kenya found elevated levels of heavy metals in the soils with mean concentrations (mg kg -1 dry weight) of 142.38, 59.12, 73.35, 116.27, 409.84 (dry season) and 144.22, 50.29, 72.14, 158.81, 368.83 (wet season) for Cr, Pb, Cu, Zn and Fe, respectively, compared with a control soil sample from an adjacent field where fertilizers are not applied having mean concentrations of 117.27, 61.87, 63.68, 123.49, 282.93 (dry season) 108.00, 50.68, 66.10, 114.23, 167.01 (wet season), respectively. The heavy metal loads in the sugarcane farms were above international standards. The levels of the same metals in the fertilizers used in the sugarcane farms were within acceptable international standards. A risk assessment of the continued use of phosphate fertilizer (DAP) in the farms based on a 50-year period, did not exceed international threshold. The soil pH values (6.18 dry season and 5.66 wet season) were low compared to the control (7.46 dry season and 7.10 wet season) a situation that could accelerate heavy metal solubility and mobility in the farm soil. Lowering of soil pH was attributed mainly to fertilizer application and partly to increased organic matter content as shown by the high mean total organic carbon content values of 8.63% (dry season) and 8.43 (wet season) in comparison with a control soil meant total organic carbon content value of 4.76% (dry season) and 5.02 (wet season). © 2010 Springer Science+Business Media, LLC.
Continued use; Dry seasons; Dry weight; Elevated level; Farm soils; Fertilizer applications; International standards; Kenya; Mean concentrations; Metal solubility; Nzoia; Organic matter content; Soil pH; Soil sample; Surface soil; Top soils; Total organic carbon content; Wet season; Agricultural chemicals; Chromium; Curing; Drought; Farms; Lead; Metals; Organic carbon; Phosphate fertilizers; Risk assessment; Soil surveys; Soils; Soil pollution; fertilizer; heavy metal; agriculture; article; environmental monitoring; industrial waste; Kenya; pH; risk assessment; season; soil pollutant; sugarcane; Agriculture; Environmental Monitoring; Fertilizers; Hydrogen-Ion Concentration; Industrial Waste; Kenya; Metals, Heavy; Risk Assessment; Saccharum; Seasons; Soil Pollutants