Assessment of heavy metal contaminations of Akor and Itu Rivers, Niger Delta Region, Nigeria

Akor and Itu Rivers are very productive rivers which serve as sources of water for domestic, farming and other industrial activities within the environment. Due to the anthropogenic activities within the environments, aquatic organisms could be endangered and which would in-turn affect humans through biomagnifications. Heavy metals of the rivers were therefore analyzed to assess their contents and provide a documented knowledge base for the respective ecosystem. Lead, iron, chromium, cadmium, zinc, manganese and mercury were analyzed over a period of 18 months using standard procedure. Results revealed that, in Akor River, concentrations of lead ranged from 0.16±0.12mg/l in the months of June and July, 2024 to 1.31±0.07mg/l in the month of October, 2023. No iron was detected in the months of June and July, 2023 while the highest level (1.70±0.06mg/l) was recorded in October, 2023 and January, 2024. Chromium and manganese had stable concentrations of 0.003±0.001.mg/l and 0.002±0.000mg/l respectively. The levels of cadmium and zinc (1.16±0.06mg/l) were similar (p > 0.05) in both rivers. In Itu River, lead and iron had a peak value of 0.02±0.00mg/l all through the sampling months. Chromium ranged between 0.01±0.00mg/l in May, 2023 to 0.03±0.00mg/l in most of the other months while cadmium had the least value (0.16±0.33mg/l) in May, 2023 and the highest (0.47±0.75mg/l) in October, 2023 and April/July, 2024. The peak zinc concentration (0.081±0.001mg/l) was recorded in the month of May, 2023 while 0.04±0.01mg/l was the highest concentration of manganese throughout the period of the present research. The stations of Itu River were relatively stable with 0.016±0.003mg/l, 0.021±0.003mg/l, 0.023±0.006, 0.032±0.006mg/l, 0.078±0.002mg/l and 0.038±0.009mg/l for lead, iron, chromium, cadmium and manganese respectively. Lead, iron and cadmium levels in Akor River were above WHO permissible limits while chromium, zinc and manganese levels were within permissible limits. At Itu River, only lead and manganese concentrations were above permissible limits. No mercury was detected in both Akor and Itu river water samples, however, Itu River exhibited a more stable concentration of heavy metals over the months. Aquatic lives are exposed to threat as these heavy metals increase and as such may affect humans. Further increase may result to a harmful environment therefore relevant policies should be instated and enforced within such areas by relevant authorities.