Detection and Quantification of Chlorpyrifos in Soil, Milk, Dip Wash, Spray Race Residues Using High Performance Liquid Chromatography in Selected Dairy Farms in Kenya

Organophosphate acaricides are well known for their extensive use in livestock for the management of Ticks and Tick borne diseases. However, the intensive use of Chlorpyrifos causes environmental pollution due to their residues accumulation. The study was aimed at detection and quantification of Chlorpyrifos in soil, dip wash, spray race residues, milk and milk products from Kilifi, Nakuru and Kajiado Counties. A baseline survey was conducted through a cross-sectional study using questionnaire, formal interview and personal observation to collect data and information on the use and type of acaricides. Thereafter soil, dip wash, spray race residues, milk and milk products from the farmers using acaricides containing Chlorpyrifos as the active compound were collected, analyzed and quantified for the presence of Chlorpyrifos using HPLC. Data obtained was stored in excel spread sheets coded and analyzed using Statistical Package for social Scientists (SPSS). Chemicals used for killing ticks included TRIATIX (12), DUODIP (11), and STELADONE (7) among others with majority of the farmers spraying once a week. Out of 11 samples collected from spray race and dip wash, 7 samples were positive for Chlorpyrifos. Nine (9) samples from the analyzed 27 samples of milk and milk products were Chlorpyrifos positive. Chlorpyrifos was also detected in 6 samples out of the 28 soil samples whereas 5 water samples from the 25 collected sample were positive of chlorpyrifos. Chlorpyrifos was not detected in milk and milk product from Kajiado County. However, the concentration of Chlorpyrifos ranged between 1.000±0.242 mgL^-1 and 2.854±0.149 mgL^-1 in Nakuru County and between 1.930±0.106 mgL^-1 and 2.017±0.049 mgL^-1 in Kilifi County. The positive soil samples were from Nakuru County with concentration ranges between 0.915±0.048 mgL^-1 to 8.556±0.549 mgL^-1. The Nakuru water samples had chlorpyrifos concentration ranging between 0.888±0.180 mgL^-1 to 1.870±0.0243 mgL^-1. The dip wash and spray race samples had a Chlorpyrifos ranges of 0.918±0.217 mgL^-1 (Kajiado County) and 3.282±0.140 mgL^-1 (Nakuru County). The study concludes that there is accumulation of Chlorpyrifos in soil, water, dip wash and spray race and milk and milk products beyond the acceptable limit set at 0 to 0.01 mg/kg body weight by WHO. The concentration of Chlorpyrifos in Nakuru County were found to be higher cozampared to Kilifi and Kajiado County. Surveillance, monitoring and regulation on the use of Chlorpyrifos in manufacturing acaricides is highly recommended.