Agrochemical Concentration Level in Zaria Dam Reservoir and Ground Waters in the Environs

Abstract

This study examines the effect of agrochemical used for faming in the Galma Dam area on the quality of water in the reservoir and well water around the reservoir. Nine sampling points upstream of the Galma Dam were randomly se- lected for the study. Also, six hand dug wells in use by adjacent communities were identified for ground water samples. The study covered the period July to September 2011. All measurements were in accordance with the Standard Methods for the Examination of Water and Wastewater. The parameters measured and their mean concentrations from the reser- voir are in the order of: Chlorides (0.600 - 0.900 mg/l); Nitrates (0.009 - 0.019 mg/l); Bicarbonates; 0.444 - 1.900 mg/l); Total Phosphates (0.173 - 3.077 mg/l); Sulphates (0.617 - 3.587 mg/l); and pH (6.4 - 7.5). For the well water samples, the results ranged from 1.58 - 3.10 mg/l; 0.14 - 0.03 mg/l; 0.60 - 2.73 mg/l; 0.08 - 1.89 mg/l; 0.33 - 2.66 mg/l and 6.05 - 7.0 respectively in the order previously listed. The results were statistically analyzed using ANOVA at 95% confidence level. Chlorides showed no significant variation between sampling points but significant variation with dates of sam- pling for surface and well waters. Nitrates variations with both sampling points and dates of sampling were insignificant. Bicarbonates variations with sampling points and dates of sampling were highly significant. Total Phosphates and Sul- phates variations with sampling points and dates of sampling were insignificant and significant respectively. pH values variations with sampling points and dates of sampling were insignificant and highly significant respectively. Generally, the mean concentrations are within the WHO maximum limits of the parameters in drinking water and recommenda- tions were made regarding the use of agrochemicals for farming in the area.