1 23 Bulletin of Environmental Contamination and Toxicology ISSN 0007-4861 Volume 94 Number 3 Bull Environ Contam Toxicol (2015) 94:387-392 DOI 10.1007/s00128-015-1465-0 Chlorpyrifos Degradation in Soils with Different Treatment Regimes Within Nzoia River Drainage Basin, Kenya Gershom Kyalo Mutua, Anastasiah Njoki Ngigi & Zachary Moranga Getenga