The liquid-liquid extraction of Petroleum contaminated surface water samples were conducted in accordance with standard procedure of US EPA. Identification and quantification of TPHs was performed by Gas chromatograph with Mass spectrometric detection (GC/MSD) in accordance with standard analytical method of US EPA 8270;625. The TPHs raw sample showed an elevated value of 104762.42 mg/L above the DPR/EGASPIN maximum contamination limit (MCL). At week 5, TPHs phytoremediations in the monoculture reactors removal efficiency was (31.28 mg/L) 99.97% and mixedculture indicated (19.72 mg/L) 99.98%; their concentrations were above DPR/EGASPIN MCL while polyculture indicated (8.91 mg/L) 99.99% value was below DPR/EGASPIN MCL. The combination of phytoremediation and vermiremediation techniques in polyculture reactors showed better and spectacular results as the biotas demonstrated good potentiality of hyperbioaccumulation to serve as hydrocarbon sinks from the ecotoxics of TPHs.

Surface water samples were collected from the Okpoka Creek, Niger-Delta using the grab samples method and were analytically investigated for petroleum contamination. The liquid-liquid extraction of petroleum hydrocarbons was carried out following standard procedures of U.S EPA 3510; 1664 method and ASTM D3695 -95(2013). The US EPA 3005A method was adopted for acid wet digestion (Aqua regia mixture of concentrated HNO3 and HCl  in ratio 1:3) for toxic heavy metal (HMs) determination. Total petroleum hydrocarbons (TPHs) was analytically identified and quantified with the representative extract (sample) using Gas chromatography mass spectrometry detection (GC-MSD) Agilent Technologies 7890A in adherence to the standard analytical method of U.S EPA 8270;625. Atomic absorption spectrophotometer (AAS) Buck Scientific 210VGP in adherence in to the manufacturer’s specifications was employed for HMs. The recorded elevated levels of the TPHs were significantly above the permissible limit of DPR/EGASPIN and HMs were also overwhelmingly above permissible limits of relevant regulatory agencies. The elevated concentrations of these contaminants of concern provided evidences of severe contamination in the study site and severe threats to environment and human health.

Soil from the vicinity of transformers installation in different locations in Jos, Plateau State was investigated for Polychlorinated Biphenyls (PCBs). The assessment was carried out for both total PCBs and congeners using Agilent 6975 GC-MS in ten different locations. The soil samples were extracted with 1:1 hexane- acetone in an ultrasonic bath, concentrated and cleaned with column chromatography using silica gel and hexane as eluting solvent. The result shows five locations were polluted with PCBs that exceed the maximum limit of 2.0mg/kg as permitted by the United States Toxic Substance Control Act (TSCA) with the following values NGS 1 (14.25), NGS 3 (4.47), NGS 6 (9.48), NGS 9 (8.21) and NGS 10 (5.05) while the others have NGS 2 (0.64), NGS 4 (1.85), NGS 5 (0.83), NGS 7 (0.95) in mg/kg respectively, NGS 8 value was below the instrument detection limit (0.0012mg/kg). The order for the total PCBs concentration in these selected locations are NGS 1 > NGS 6 > NGS 9 > NGS 10 > NGS 3 > NGS 4 > NGS 7 > NGS 5 > NGS 2. The carcinogenicity of the dioxin-like PCBs calculated as total toxicity equivalence concentration (TTEC) in these selected locations corresponds to NGS 1 (0.00001), NGS 2 (0.0000051), NGS 3 (0.0000054), NGS 4 (0.0000051), NGS 6 (0.0000063), NGS 7 (0.0000078), NGS 9 (0.0000051) and NGS 10 (0.0000051) respectively. The total cancer risk computed by addition of cancer risk due to ingestion, inhalation and dermal contact revealed that all the locations have very low to low cancer risk compared with the value recommended by the United State.

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Arsenic concentration of agricultural soil and surface water used for irrigation were surveyed in two abandoned mining sites of Jos South Local Government Area. DB-Zang and Dorowa total dissolved solid, total hardness, electrical conductivity, temperature and pH of the agricultural soil and surface water were determined according to standard procedure. Result indicates that Total dissolve solids in W1 was 156±2.00mg/L and for W2 (160±2.00mg/L), total hardness W1 (35.20±4.70mg/L) and W2 (44.67±4.70mg/L), electrical conductivity for W1 was 0.240±0.189µs/cm and W2 was 0.120±0.189µs/cm ,electrical conductivity for S1 (0.49±0.16µs/cm), S2 (0.17±0.16µs/cm), temperature for both water was 28.00±0.00oC for soil are 18.00±0.00 o C, pH for W1 (7.10±0.05) and W2 (7.20±0.05), pH for S1 (6.90±0.15) S2 ( 6.60±0.15). The concentration of Arsenic in soil L2 is14.00±0.70µg/kg which is in agreement with WHO recommended level of Arsenic in soil and for L1 257.00±120.00µg/kg which is not in agreement with the WHO recommended level of arsenic, while in water for L1 was 3.00±0.50µg/L which is not in agreement with the WHO recommended level of arsenic and L2 was 48.00±0.70µg/L which is not in agreement with the WHO recommended level of arsenic. The cultivation of food crops in those areas are not recommended.