Geochemical and Geospatial Distribution of Organic Contaminants in the Flood Plain of Ekpetiama, Niger Delta Region of Nigeria

Abstract

This study investigated the geochemical and geospatial distribution of organic contaminants in the floodplain water and sediments of Ekpetiama in the Niger Delta Region of Nigeria. This study is necessary because there are limited data on the level of organic contamination in this section of the Niger Delta Region of Nigeria. The extinction of planktons in Ekpetiama became a source of concern to the residents. This concern is because this section of the coastal plain provides fisher folks with livelihood. So, there was a need to track the source of contamination in this part of the Niger Delta region. Previous studies have suggested a high level of Total Petroleum Hydrocarbon and Total Hydrocarbon Content as possible sources of reduced dissolved oxygen in similar deltaic terrain. A total of 10 water and 10 sediment samples were collected and analyzed in triplicate at an interval of 100 m in the flood plain. A particle size analyzer was used to perform particle size analyses of air-dried sediments. The American Public Health Association method (APHA) was used to do the chemical analysis of the water samples. Here, a liquid-liquid extraction procedure was performed on sediment samples using 30 mL of Dichloromethane (DCM) as the extracting agent. The results were subjected to statistical validation. The mean grain size ranged from 2.37-4.83, kurtosis (1.94-0.49), and skewness (-0.8-0.71). The contaminant indicators (pH, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen and Total Organic Carbon) point to the presence of organic contamination of the flood plain. The results indicated a total petroleum hydrocarbon range of 0.47-0.87 ppm in water and 0.69-0.96 ppm in sediments and a total hydrocarbon content range of 1.10-2.80 ppm in water and 2.56-3.90 ppm in sediment# samples. The results were above the permitted limits of the World Health Organisation. The source of ecological damage is the abnormal concentrations of organic contaminants in the flood plain. These results significantly caused ecosystem damage and human health effects in the food chain. This study provides information to the National Oil Spill Detection and Response Agency for a cleanup process.