Benthic Algae and Banana (Musa spp.) as Bio-monitors of Heavy Metals Pollution in Alaro River, Oluyole Industrial Estate

Alaro River is the main receiving water body for industrial effluents from Oluyole Industrial Estate. Previously, studies on environmental monitoring of heavy metals pollution in Alaro River have focused on the levels of heavy metals in sediment samples, water samples and fishes. However, studies on bio indicators of heavy metal pollution such as algae and banana (Musa spp.) plant, which are commonly found within/around the river, are still lacking. This study was therefore conducted to determine the concentrations of selected heavy metals in algal biomass and banana plant in order to establish the feasibility of using the two indicators in phytoextraction and bio-monitoring of environmental quality. Algae samples, banana leaves and roots, and soil samples were collected at different sampling points along the course of the river and analysed for heavy metals. Translocation factor for banana and pollution index for soil samples were determined. Analysis of algal biomass showed that zinc was the most accumulated with values ranging from 133.27 ± 6.36 to 299.98 ± 130.13 mg/kg. Copper, lead and chromium were also detected in varying concentrations while cadmium was not detected in all the samples. Similarly, copper (10.90 ± 3.22 – 11.96 ± 1.98 mg/kg), zinc (50.59 ± 15.14 – 88.52 ± 32.73 mg/kg) and chromium (10.28 ± 5.98 – 12.13 ± 6.32 mg/kg) were detected in the roots of banana while only zinc (17.69 ± 2.92 – 29.02 ± 10.01 mg/kg) and copper (5.07 ± 0.86 – 10.10 ± 5.98 mg/kg) were detected in the leaves. Copper (0.49) was the most translocated metal for banana plant. The potential to bio-concentrate metals were in the order of zinc (1.24), copper (1.12) and chromium (0.44). The mean soil pollution load index was determined to be 0.62. From the results of the study, it can be concluded that algae and banana (Musa spp.) plant have potential as aquatic bio-filter plants for phytoextraction and bio-monitoring of heavy metals pollution in Alaro River