环境与分析毒理学

Impacts of Artisanal Refining Activities on Soil and Water Quality in Parts of Okrika and Ogu-Bolo Areas of Rivers State, Nigeria

Abstract

Nwankwoala HO, Harry MT, Amangabara GT and Warmate T

This study aims at the assessment of the impacts of artisanal refining of crude on soil and water quality in parts of Okrika and Ogu-Bolo areas of Rivers State, Nigeria. Standard sampling methods were used in the study. A total number of sixteen (16) sampling points were selected using random sampling techniques for the water points and soil samples within Ogu-Bolo and Okrika. Water and soil samples were analyzed in the laboratory using standard methods. The ArcGIS version 10.3, ENVI version 4.7, Surfer 10, SPSS 22 and Microsoft Enterprise were used for the interpretation. The Digital Elevation Model (DEM) was created from the elevation data obtained from Short Radar Thematic Mapper (SRTM) satellite image and contour extracted from the topographic map. The influence of the soil type, slope, flow accumulation and flow direction of the study area was used to delineate the level of contaminant plume. This was generated from the DEM using the ArcGIS 10.3 3-D analyst tool function. A water Quality index rating of 1 was measured in the study area which is an indication that the water is very bad. Also, the physio-chemical analysis on soil and water revealed poor water and soil. Water analysis showed high concentration of Fe and Zn which made the water in such area unsuitable for drinking. Also, the soil samples recorded high levels of crude content from 1 m, with concentration reducing with depth up to 3 m. A general contamination map of Okrika/Ogu-Bolo was modelled, indicating the contamination rating of total land mass of the study area, with 23.59 km (5.71%) rated very good, while 85.65 km (20.71%) were rated good. Also, 140.37 km (33.95%) had only showed moderate level of contamination while 112.56 km (27.22%) recorded bad level of contamination, with 51.29 km (12.40%) of the total land mass having very bad contamination record. Water quality assessment should be carried out regularly to determine any future pollution of the water. It is recommended that artisanal refining activities in the area should be discouraged to avoid further contamination in the area.