Petroleum Water Contamination Resulting from Change in Land-Use in Paloich, South Sudan: Azolla pinnata and Lemna minor L. as an Efficient Bio Treatment Tool

Abstract

The study focused on the change in land-use and phytoremediation and biosorption efficacy of Lead and Cadmium from the petroleum-contaminated water by Lemna minor L. and Azolla pinnata. For the study of the change in land-use in Paloich, satellite imagery of Paloich between 2000 and 2020 was obtained from http://www.earthexplore.usgs.org/ and analyses. Water samples were collected at different points of Paloich. Experimental set-up consisted of four main samples sets viz: Lemna minor L. and petroleum-contaminated water, Azolla pinnata and petroleum contaminated water, combination of Lemna minor L., Azolla pinnata and petroleum-contaminated water then distilled water (control) all containing 3 liters of the water. Samples were left for 28 days. Physico-chemical parameters, heavy metals (Pb and Cd) and biosorption capacity were analyzed. The result indicates the changes in the land-use that occurred in the area of study for a given period (2000-2020). Built-up area, mining site and environmental degradation have increased by 8 percent between the periods. The reason behind the increase can be as a result of increase in population. The result also indicates high efficiency in pollutant reduction in the set-up containing the combination of Lemna minor L. and Azolla pinnata in which the Cd and Pb reduction efficiency recorded was 95% and 97% respectively. While set up containing Azolla P. had Pb and Cd reduction efficiency of 83% and 87% respectively. However, the set up containing Lemna minor L. has Pb and Cd reduction efficiency of 91% and 85% respectively. A significant absorption of the metals (Pb and Cd) were seen in the samples with the mixture of Lemna minor L. and Azolla pinnata. As such this study reveals the potentiality of Lemna minor L. and Azolla pinnata as some excellent phytoremediation candidates in the treatment of effluents containing Lead and Cadmium; however, we also recommend further studies on the efficacy of such plants in other classes of heavy metals.