GC Determination of Herbicides Residues and Health Risk Assessment of Some Crops from Selected Farmlands in Pankshin LGA Plateau State

Abstract

The use of herbicides in farming activities has significantly improved agricultural yields as bumper harvest has been recorded. In its usage however, the residues of the herbicides after successive accumulation by the years could be a threat to humans and other non-target organisms after they have performed their primary roles. From oral interview with the farmers it was discovered that glyphosate, paraquat dichloride and 2,4-dichlorophenoxy  acetic acid are mostly used within the study area which are hazardous and should be handled with utmost care. Crop samples were obtained alongside soil samples from Bumnan, Bwarak, Larpya and control sites. The samples were pretreated and extractions of the herbicides residues was carried out with the aid of acetone, dichloromethane and hexane as solvents.  GC analysis was carried out on the extracts to determine the herbicide residues concentrations and the following results were obtained in mg/kg:  Rice from Larpya soil contained 0.002 mg/kg and 0.0124 mg/kg, Potatoes crops collected from Bwarak soil; 0.0021 mg/kg and 0.0012 mg/kg, groundnut from Bumnan soil; 0.0038 mg/kg and 0.0094 mg/kg, potato from control soil; 0.0016 mg/Kg and 0.0009 mg/kg and groundnut also from control soil; 0.0003 mg/Kg and 0.0012 mg/Kg of 4,4- bipyridine and 2,4-diphynoxyacetic acid respectively. A statistical analysis was carried out using one way ANOVA; p≤0.05 and there was no significant difference among the mean values The bioaccumulation and health risk index for all the crops were below 1 as recommended by EFSA, 2007) and are considered to be of no health hazard to humans and the environment.