Investigation of Possible Impact of 2,4,6-Trinitrotoluene (TNT) Explosive Seismic Energy Source on the Nitrate Content of Groundwater in Sagbama Area, Niger Delta, Nigeria

The impact of 2,4,6-trinitrotoluene (TNT) high explosive seismic blasting operations on the nitrate content of groundwater in Sagbama area, Niger Delta, Nigeria was investigated. A total amount of 116,349.2 kg 2,4,6- trinitrotoluene (TNT) was detonated in 60, 398 source point in an area of 771.26 square kilometers of Sagbama area. Eleven boreholes was used to study the impact of the TNT shots in Sagbama area. Ultraviolet spectroscopic method was used in the determination of nitrate in the groundwater. A control sample was taken from the borehole stations by sampling a day before detonation of TNT. Subsequently, sampling was carried out a day after TNT detonation and then, on a fourth-nightly basis. The average nitrate value of the control (water before detonation) was 2.53 mg/l. After dynamite detonation, the average measured nitrate values ranged from 2.56 to 2.65 mg/l. These variations of the water sample test values in comparison with the values of the control samples were not significant enough to be said that there was any groundwater contamination. Computation of the grain size distribution curve parameters yielded a permeability value of 3.24 cm/sec. The representative litho logy of Sagbama area as revealed by the borehole logging showed that they are mainly non-plastics also categorized as cohensionless sands. The presence of silty sands at 4 to 5m depths could be an obstruction to infiltration of contaminants from dynamite detonation. However, the nitrate content of the groundwater was below 10 mg/l compliance limit of U.S. Environmental Protection Agency (EPA) standards.