Assessment of Heavy Metals Concentrations in Lake Gwakra, Girei Local Government, Adamawa State, Nigeria

This study aimed at evaluating heavy metals of Lake Gwakra for the dry and wet seasons of 2022. Samples were collected from three different locations within the lake using clean one-liter bottles at a depth of 0.3m for laboratory tests. To maintain the cations in solution and prevent bacterial growth, oxidation, and metal precipitation, the composite samples were treated with HNO3. Subsequently, the samples were stored at 4°C to minimize evaporation. Atomic absorption spectroscopy (AAS) was employed to determine the concentrations of the heavy metals which included, iron (Fe), manganese (Mn), cadmium (Cd), chromium (Cr), zinc (Zn), lead (Pb), and copper (Cu). The results revealed that during the dry season, the concentration of iron ranged from 2.20mg/l to 2.24mg/l, while in the wet season, it ranged from 2.70mg/l to 2.90mg/l, both falling within the recommended limits. Manganese concentrations in the dry season ranged from 0.06mg/l to 0.08mg/l, with an average of 0.07mg/l, whereas in the wet season, the average concentration was 0.16mg/l, exceeding the recommended limit. In the dry season, cadmium concentrations varied from 0.11mg/l to 0.13mg/l, averaging at 0.12mg/l, whereas in the wet season, the average concentration was 0.03mg/l, surpassing the recommended limit. Chromium concentrations ranged from 0.45mg/l to 0.48mg/l in the dry season, with an average of 0.47mg/l, and in the wet season, the concentration ranged from 0.43mg/l to 0.45mg/l, averaging at 0.44mg/l, all surpassing the recommended limit. Zinc concentrations in the dry season ranged from 0.12mg/l to 0.14mg/l, with an average of 0.13mg/l among other results of the heavy metals. Regular monitoring protocols to track water quality and identify potential sources of contamination was recommended among others.