STUDIES ON THE ENVIRONMENTAL IMPACT OF PETROLEUM / CRUDE OIL POLLUTION

Heavy metal (Zn, Cu, Pb, Cr, Cd and Ni) concentrations were determined in the leaves, stems and roots of fluted pumpkin, harvested from Egi community, Rivers State. Samples were collected from four (4) different locations, namely: Location 1 (New Elf Road), Location 2 (Ugada Imeagi), Location 3 (Egita Land) and Control (Ohali-Elu). All samples were analysed using AA500 model Atomic Absorption Spectrophotometer. Results of heavy metal concentrations (mg/kg) in the leave, stem and root revealed that all metals were below permissible limits of food crops as specified by WHO/FAO/DPR (2012) in both seasons, with exception of Cd in the wet season which recorded 0.911(Control), 0.723 (Location 2) and 0.711 (Location 3) for leaf, 0.283 (Control), 0.511 (Location 2) and 0.521 (Location 3) for stem and 0.543 (Control), 0.35 (Location 2) and 0.39 (Location 3) for root which were above permissible limit of 0.02 mg/kg. The results above shows an evidence of oil and gas related activities, and other possible anthropogenic Cd contaminants in the study area. It is therefore recommended that more studies on other metals and constant monitoring of the environment should be carried out.

The concentration of heavy metals (Cd, Pb, Fe, Al and V) in surface water and sediment and their sediment enrichment factor were determined in Soku oil field area of Rivers State, Nigeria. Surface water and sediment were collected in duplicates, bimonthly from four stations from July 2017 to May 2018, upstream and downstream of the Soku oil field. The physicochemical parameters (ToC, Dissolved oxygen, salinity, pH) were measured according to standard methods. The total metal concentrations were analyzed using AANALYST 400 Perkin Elmer Atomic Absorption Spectrometer. The heavy metal mean concentrations (mg/L) in surface water were 1.95(Fe), 0.88(Al), 0.64(Pb), 0.08 (V) and 0.01(Cd), while in sediments the heavy metal concentrations (mg/kg) were 6608.63(Fe), 2.84(Pb), 2.54(Al), 2.16(Cd) and 1.90(V). All recorded values were above permissible limits for both water and sediment with the exception of Al in water. Heavy metals concentrations were generally high in the dry season depicting heavy metal pollution and suggestive of high dilutions by heavy rain fall in the wet season. Higher concentrations of heavy metals in the sediment as against the surface water were indicative of overtime pollution of the river and confirmation of the sediment as a sink for heavy metals. Enrichment factor using Fe as the reference element ranged from depletion (0.0003) to extremely significant enrichment of 137.27 in the order of Al˂V<Fe<Pb<Cd indicating a high Cd and Pb pollution, of the environment which is a potential threat to aquatic and human life. The determination of Al level in water and sediment was a first in the area. Al at the recorded pH between 6-7, may form soluble hydroxides that act as respiratory toxicant for fish. Keywords: Heavy metals; Soku oil field; Niger delta; Aluminium; Enrichment factor Received:

Background: It is evident that Ekerekana Creek in Okrika Local Government Area of Rivers State serves as the reciepient water body (environment) where petroleum Refinery effluent / run off are discharged. A study was conducted on Ekerekana Creek and its adjourning rivers (Okochiri, Okari-Ama and Ogoloma Rivers) to determine the effect of refinery effluent on plankton and benthic composition and distribution of Okrika River. Methods: Standard methods were used to ascertain the abundance and richness in population of taxa and species distributed at 4 (four) selected stations; Point of discharge of refinery effluent (S1), Upstream river water (S2), Downstream river (S3) and Ogoloma River (control station). Result: The distribution and abundance of phytoplanktons amongst the sampling stations were very poor. A total of 40 taxa were recorded with 3 families namely; Bacillariophycea, Cyanobacteria and Chlorophyceae with Bacillariophyceae dominating the entire phytoplankton distribution. In the same way the distribution and abundance of Benthic Organism were also very poor, a total of 6 (six) species from the family Nereidae were recorded namely; Leonates decipiens, Dendronereis arborifera, Lopdorhynchus ucinatus, polycheate larvae, Capitella capitata and Arenicola sp. Conclusion: It is evident from the results that the effluents / runoff discharged into the creek impacted negatively and species thriving in the study area especially at the point of discharge were pollution tolerant indicating continuous discharge of the effluents may totally eliminate the benthic fauna of the area, therefore continuous discharge of contaminated effluents into the creek should be discouraged while the development of more effective effluent treatment facility should be pursued.

The total hydrocarbon concentration (THC) in water and sediment of a site suspected to be chronically polluted by hydrocarbons and two other relatively unpolluted control sites along Elechi Creek in Port Harcourt were sampled once every two months between April – October 1989. During the same period, the distribution and diversity of littoral macrofauna were determined. The THC of 580 – 750ppm recorded in sediment in the industrial zone was found to be higher by 200ppm than those recorded at the other transects. The total macrofaunal numbers of 13 and 18 individuals/m3 at MLTL and MTL respectively were lower at the same tidal levels of the control transects. Diversity estimated by d and H was found to be generally low, also polychaetes found in the polluted zone included Nereis agnesiae, Marphysa depressa, Lumbrinereis bifilaris and apitella capitata.

The total hydrocarbon concentrations (THC) in water and sediment at an obviously oil polluted industrial jetty and three other relatively unpolluted control sites along Elechi Creek off Bonny Estuary were sampled bimonthly for 8 months (October 1996 – May 1997). During the same period, sampling with drag net monitored the distribution of mullet species. The THC in water and sediment around the industrial jetty were found to be significantly higher than at the sites throughout the sampling period. The density of mullets at the polluted sites was lower than those of the other stations. On statistical analysis using ANOVA at P > 0.05, the mullets showed significant differences in their diversity with the stations and this was influenced by the levels of hydrocarbons detected at the various stations. The THC compared to those found in polluted areas elsewhere in literature indicated the test station to be polluted. Such high levels of hydrocarbon would greatly affect the density and diversity of mullets in the sampled water body and this will to a large extent affect the quantity and quality of fisheries of the area. Also, Mugil curema and Lisa grandisquamis were found to be more sensitive to environmental stresses than the other species.

The effects of the ingestion of oil-contaminated feeds an egg production of poultry birds (Gallus domesticus) were investigated. The results indicated that those birds which ingested the treated feeds laid means of 5.0, 2.7 and 1.9 eggs for the 0.75ml/300g, 15ml/300g and 3.0ml/300g treatment levels, while the control laid 8.0 eggs per ten (10) birds per day. The weights of the eggs of the control (52.19+1.73g) were significantly higher than the treated cases, which were 56.29g; 61.83; and 64.57g for treatments 1, 2 and 3 respectively (P≤0.05). The mean albumen height also varied significantly with 6.06cm for the control and 5.49, 5.68 and 5.30cm for T1, T2 and T3 respectively. Also the Haugh Unit ranged from 83.96 for the control to 71.52, 70.01 and 69.01 for T1, T2 and T3 respectively. The egg shell thickness for the control (0.34cm) was significantly higher than the treatment values of 0.23cm, 0.20cm and 0.19cm for T1, T2 and T3, yolk index analysis showed significantly higher value for the control 1.18 compared to 1.0, 0.99 and 1.0 for T1, T2 and T3. These effects would collectively affect the quality of the egg, survival of the embryo and their hatchability. It would also increase the chances of egg spoilage and reduce their market value. The speedy clean up of oil polluted areas is suggested as a means of reducing the overall impact an birds.

Abstract Acute toxicity experiments (96hr bioassays) were conducted to determine the toxicity of crude oil and mixtures of crude oil and the dispersant, Corexit 9527 to the mangrove oyster Crassostrea gasar. The rates of net uptake of hydrocarbons were also determined in treatments containing crude oil only and crude oil + dispersant mixtures. The oyster showed high resistant to oil as minimal mortalities were observed in crude oil concentrations up to 50ppm. The mortality profile in crude oil + dispersant mixtures showed that there was a synergistic interaction in their toxicity. Higher rates of accumulation were recorded in the oil + dispersant treatments in comparison with treatments with oil alone. This was probably because the dispersant breaks up the oil leading to higher solubility and droplets in solution that are then taken up by the filter-feeding oysters. The results showed that cleaning up of a spill with Corexit 9527 is likely to lead to higher effects on oysters than oil alone. Keywords: Crude oilo, Corexit 9527, Oysters, Toxicity, Synergy, Accumulation

ABSTRACT Assessment of crude petroleum uptake was undertaken using grasshoppers (Zonocerus variegatus, L.) exposed to feeding on leaves of sweet potato (Ipomoea batatas L. Lam.). Natives of some states in the Northern region and some parts of the Niger Delta and the middle belt eat grasshoppers as snacks and as meat supplements. It therefore became necessary to assess hydrocarbon uptake in both the vegetable and the insect that feed on them. Assessment of uptake via the food web would identify levels of hydrocarbons accumulated in plants and hoppers and consequently explain biomagnification. Germination was affected by higher doses of crude petroleum (R2< 0.63). Both nymph and adults were affected by different doses of crude petroleum. Positive correlation existed between total hydrocarbons in nymphs of hoppers (r2 = 0.51); the relationship between THC in sweet potato leaves and crude petroleum uptake was a loose type (r2 < 0.39). Mortality of both nymphs and adults was also close dependent. A conclusion was drawn that both sweet potato and the grasshoppers accumulated hydrocarbons and their nutritional status, growth, water balance became affected and consequently resulted in the mortality of the insects. Evidence of bioaccumulation in the hoppers exposed by feeding on the plants was also reported. Keywords: Edible insects, Zonocerus variegatus, Crude petroleum, Uptake, Sweet potato