Evaluation of the Total Dispersion and Distribution of Petroleum Hydrocarbons in the Aya Stream, Located in Niger Delta: Implications on the Quality and Health of Aya Water Stream
Globally, oil spills are known catastrophic events with harmful consequences that tend to endanger plant, animal and human life. The dispersion and distribution of petroleum hydrocarbons levels were investigated to evaluate its effect on the quality and health of Aya stream, located in the Niger Delta sub region, south east Nigeria. Water samples were collected from the stream, which is the most available source of water in Ikot Ada Udo local community, five years after an extensive oil spillage between the months of June and November 2012. These samples were analyzed to assess the level of total petroleum hydrocarbon (TPH) and physicochemical enrichment using Spectrophotometric with 1g of Bonny Light and Bonny Medium Crude Oils dissolved in 1000 ml of tetrachloromethane were used as standards as well as insitu measurements of water temperature and dissolved oxygen. TPH concentrations ranged from 0.21mg/l in dry season (September, October, November) to a maximum level of 0.33 mg/l in wet season (June, July, August) during the study. The mean concentrations found for physicochemical parameters during wet and dry seasons respectively were: temperature (27.67±0.29 & 27.83±0.290C), DO (3.47±0.65 & 3.44±0.67 mg/l), Cd (0.03±0.003 & 0.03±0.01mg/l), Pb (0.17±0.06 & 0.18±0.04 mg/l), Ni (0.08±0.01 & 0.08±0.005 mg/l), V (0.02±0.01 & 0.02±0.01 mg/l).The distribution pattern of trace heavy metals in the stream water followed the sequence: Pb>Ni> Cd>V. In all cases, Pb was the most abundant and V the least abundant metal. Elevated levels of some physicochemical parameters shown to correlate significantly (p=0.05) and associate with the oil spill infer that Aya stream has been severely polluted. Statistical analysis (t-test) of seasonal levels of TPH in water samples showed positive relationship (t=0.55, p=0.05). The implication of these results is that the concentrations of the studied parameters did not depend on seasonal influence but were connected with the incessant exposure of the site to oil seeps from the well-head. The high levels of lead above permissible limits in the studied samples poses a health threat, hence, the removal of the well-head and future situation of such structures away from the source of communal water source should be implemented to preserve the quality and health of the water source.