Potential Ecological Risk of Swamps Sediments in Illegal Refineries Sites: A Case Study of Isoko South, Delta State, Nigeria

Abstract

This study was carried to determine the level of heavy metals toxicity in swampy forest of Isoko South, Delta State, Nigeria. Sediments samples were collected from nine spatial points, within the swampy forest of Enwhe community of Delta State, Nigeria. The study area contained clusters of illegal crude oil refineries, before they were destroyed by the Nigeria military, during the first quarter of 2020. A total area of 1 km2 of the swampy environment was covered in this study. Six toxic heavy metals (Cu, Zn, Cr, Cd, Pb, and Ni) contents, in the sediments were determined in accordance to international approved standards. The results revealed that the activities of the illegal refineries located in the study area, significantly increased the heavy metals toxicity in the sediments.  When compared with the results obtained from a reference point, the concentrations of the heavy metals were significantly higher, across the study area. Within the study area, spatial points B and D sediments contained the highest heavy metals concentrations. In addition, the study revealed that contamination factor of the sediments ranged between moderate and high degree of heavy metals contamination. This portrayed the potential ecological risks of the illegal refineries activities, to the environment of the region. Therefore, if these illegal refineries activities are allowed to continue unabated, they will cause a serious ecological risk to the Niger Delta region ecosystems.