Assessment of Surface Water Quality using Heavy Metal Pollution Index of River Gongola at Yamaltu-Deba LGA, Gombe State, Nigeria

The study assessed Heavy Metal concentrations of surface water of River Gongola, Gombe State, Nigeria in four (4) stations. The sampled water were digested and analyzed for heavy metals using AAS model 205. Cu (0.036, 0.032, 0.035, 0.039) Pb (0.006, 0.001, 0.004, 0.003), Cr (0.033, 0.034, 0.045, 0.021), Fe (0.026, 0.028, 0.017, 0.027) and Zn (0.963, 0.535. 0.878, 0.333) in all the stations were below the WHO/NSDWQ limit. Cd (0.011, 0.013, 0.006), As (0.030, 0.033, 0.024), Ni (0.095, 0.099, 0.091) in Stations 1, 2 and 4 and Mn (0.471) in Station 2 were higher than the limit. Analysis of Variance revealed that there were significant differences (P<0.05) with months for all the metals but no difference across stations except for Zn. Tukey Post Hoc Test revealed that stations 1 and 3 which were not significantly different from each other, varied significantly with stations 2 and 4. Heavy Metal Pollution (HPI) calculation revealed that all the stations had HPI values >100 (253.13, 295.92, 105.52 and 103.52) for stations 1, 2, 3 and 4 respectively. And these are above the threshold of 100. Cd concentrations contributed significantly to the high HPI values in all stations. However, station 2 had the highest value followed by 1. This result shows that the water from this river is contaminated with respect to Cd, As and Ni.