ENVIRONMENTAL IMPACT ASSESSMENT OF A PROPOSED TANKFARM

ABSTRACT

This study was carried out to assess environmental impacts of a proposed tankfarm which is to be situated at the Olokola Free Trade Zone in Ondo State (OKFTZ).

It encompasses various field sampling which includes soil, air and noise sampling taken from the proposed site. These samples were tested in the laboratory for parameters such as Total Hydro Carbon, pH values, Total Mean Percentage of Organic Matter, Heavy Metal Investigation, cation concentration. The Total Hydro Carbon which ranges from 4.8 to 33.0 milligram per kilogram(mg/kg) in the wet season and 4.0 to 78.5 mg/kg for dry season. The THC is reflective of an unpolluted environment, and it is widely accepted that soils with a hydrocarbon level below 100 mg/kg are considered unpolluted. Heavy metals investigation showed that Iron had the highest mean concentration (2213mg/kg) followed by Zinc (4.82mg/kg) and Copper (3.78mg/kg) for dry season while for wet season, Iron had 2039mg/kg followed by Zinc (8.68mg/kg) and copper (3.0mg/kg). The concentration of the monovalent cation in the soils was generally high. Sodium (Na) concentrations ranged between 2,136 and 7,341mg/kg in the wet season and 6,175 and 10,308 mg/kg in the dry season while potassium (K) ranged between 0.09 and 0.15 mg/kg in the wet season and 0.04 and 0.45mg/kg in the dry season. The high sodium content could be attributed to the proximity of the study area to the ocean. 

Suspended Particulate Matter Levels for Wet and Dry Season on shows that there are more suspended particulate matter in the dry season as the result indicated a value of 196 µg/m3 against 64µg/m3 in the wet season. Comparing these findings with EGASPIN guidelines for national air quality standards, more air quality monitoring is needed during the dry season as it reaches a high of 196 though it is still within the EGASPIN (Environmental Guidelines and Standards for Petroleum Industries in Nigeria)  limits. Noise measurements showed that the measured levels varied significantly in the different locations monitored and ranged from a low of 55.2dB to a high of 66.7dB, for the dry season and 52.7dB to a high of 67.9dB, for the wet season as compared to the World Bank standard of 45 dB(A) for residential areas during the daytime. It is recommended that environmental performance be monitored regularly to ensure compliance and those measures to be taken where necessary. The OKFTZ site is generally suitable for the proposed bulk fuel storage facility and all environmental risks can be minimized and managed through implementing preventative measures and sound environmental management systems.