Assessment of Physicochemical Properties and Heavy Metal Load in Soils of Ebocha Gas Flaring Site in Rivers State, Nigeria

Abstract

The negative impact of gas flaring on the environment cannot be overemphasised. This study assessed the effect of gas flaring on the physicochemical properties and heavy metal contents in soils of Ebocha gas flaring site in Rivers State. It involved the assessment of various distances from gas flaring point to 200 meters away (50 m, 100 m, 150 m, and 200 m) which represents the extent of gas flared pollution on soils to determine the physicochemical properties and heavy metal load. The gas flaring significantly decreased soil organic carbon and calcium content when compared with non-gas flaring polluted soils. Soil acidity increased, soil exchangeable ions decreased. N, P and K were altered in gas flared soils when compared to the controls. There were detrimental effects on soils physicochemical properties. Heavy metals observed were Cd (Cadmium), Ni (Nickel), As (Arsenic), Cr (Chromium), while Pb (Lead) was not detected. The concentration of heavy metals in gas flared soils decreases down soil depth from 0-15 cm to 45-60 cm respectively. The gas flaring extremely caused the acidic nature of gas flared soils. Coefficient of variation (CV) in percentage shows significant increase in acidic nature of the gas flared soils when compared with the control soils.

Physicochemical properties and metal speciation in gas flare-impacted soils in Ibeno, NigeriaPhysicochemical properties and metal speciation in gas flare-impacted soils in Ibeno, NigeriaPhysicochemical properties and metal speciation in gas flare-impacted

“…The mean value of Pb obtained in the studied gas flare-impacted soils is also higher than 1.56 mgkg -1 reported in the control site. This is in agreement with the report by Achieche et al [37] in their study. Consequently, gas flaring activities in the area might have affected the accumulation of Pb in the studied soils.…”

“…The mean OC value of the studied soils is lower than 7.26 % obtained at the control site. The higher OC contents in the control soil is consistent with the findings by Achieche et al [37]. Consequently, gas flaring has a negative effect on the availability of soil organic carbon thereby affecting agricultural activities [14].…”

“…The concentration of total Pb ranged from 8.24 to 13.29 mgkg -1 with a mean value of 10.73±1.90 mgkg -1 (Table 3). The reported range is higher than 2.5 -3.5 mgkg -1 obtained in the gas flared-impacted soils by Achieche et al [37]. The mean value of Pb obtained in the studied gas flare-impacted soils is also higher than 1.56 mgkg -1 reported in the control site.…”

“…Total Ni levels in the studied gas flare-impacted soils as shown in Table 3 range between 1.92 and 2.40 mgkg -1 with a mean value of 2.15±0.20 mgkg -1 . This range is lower than 15.10 -20.40 mgkg -1 obtained in gas flare-impacted soils by Achieche et al [37]. The mean concentration of Ni in the studied gas flare-impacted locations is higher than 0.87 mgkg -1 .…”