HEAVY METALS CONTAMINATION OF WATER, ELEPHANT GRASS - Pennisetum purpureum, AND SOIL OF OGINI, DELTA STATE, NIGERIA

Abstract

The impact of petroleum exploration activities on the concentration levels of iron [Fe], zinc [Zn], copper [Cu], lead [Pb], and chromium [Cr] in the water, vegetation, and soil of Ogini was assessed. Samples were collected from water effluent, soil, and elephant grass leaves around the flow station. Atomic absorption spectrophotometer techniques were employed to analyze sample solutions. Results indicated varying heavy metal concentrations in the samples. Topsoil samples contained 18.50-27.10 mg/kg Fe, 16.30-19.40 mg/kg Zn, 1.81-2.44 mg/kg Cu, 0.64-2.33 mg/kg Pb, and 0.10-0.81 mg/kg Cr. Bottom soil had 19.30-27.10 mg/kg Fe, 17.90-23.00 mg/kg Zn, 3.01-4.20 mg/kg Cu, 0.91-3.33 mg/kb Pb, and 0.40-0.91 mg/Kg Cr. Background samples were 3.00 ± 1.70 mg/kg Fe, 4.27 ± 0.15 mg/kg Zn, 3.07 ± 0.06 mg/kg Cu, 1.67 ± 0.25 mg/kg Pb, and 0.93 ± 0.11 mg/kg Cr. Mean concentrations of heavy metals in water samples were 2.30 ± 0.45 mg/l Fe, 0.06 ± 0.01 mg/l Zn, 0.01 ± 0.01 mg/l Cu, 0.05 ± 0.00 mg/l Pb, and 0.01 ± 0.001 mg/l Cr. Mean concentration levels in elephant grass leaves were 9.32 ± 0.45 mg/kg Fe, 8.65 ± 0.35 mg/kg Zn, 3.08 ± 0.44 mg/kg Cu, 2.11 ± 0.20 mg/kg Pb, and 0.47 ± 0.11 mg/kg Cr, exceeding control sample values. Levels of Zn, Pb, and Cr in elephant grass leaves exceeded WHO/FAO toxicity reference values, except for Cu. Fe and Zn samples surpassed background soil samples, suggesting potential environmental implications of petroleum exploration activities.