Physicochemical properties and selected metals in soils of Ohaji-Egbema, Imo State, Nigeria

This study assesses the physiochemical characteristics and heavy metals content of crude oil polluted soils and non-polluted soils from Ohaji/Egbema, Imo State. Soil samples were collected at depths of 0-30 cm at each sampling point and then analyzed using standard analytical methods. Data from the five areas were compared to standards for soils in Nigeria and in World Health Organization (WHO) data banks. The results obtained from the analysis showed an average pH of (4.88 ± 0.02 to 5.02 ± 0.04) for polluted soil and (6.57 ± 0.05 to 6.82 ± 0.03) for non-polluted soil, electrical conductivity (571 ± 1.1 to 592 ± 0.8 µS/cm) for oil polluted soil and (383 ± 0.5 to 415 ± 1.6 µS/cm) for non-polluted samples, moisture content (5.2 ± 0.2 to 9.1 ±0.1 %) for polluted soil and (4.5 ± 0.1 to 4.7 ± 0.3 %) for non-polluted soil samples. There was no significant difference in temperature and organic matter for both the polluted and non-polluted soil samples. The heavy metals analysis results showed Fe3+ (0.615 to 0.989 ppm) for oil-polluted soil samples and (0.0453 to 0.273 ppm) for non-polluted soil samples, Pb2+ (0.017 to 0.180 ppm) for oil-polluted soil and (0.008 to 0.010 ppm) for non-polluted soil. The study reveals that areas that are polluted need urgent remediation if the soil is to be used for agricultural purposes.