Oil Pollution and Water Quality in the Niger Delta: Implications for the Sustainability of the Mangrove Ecosystem

Table of contents

1. Introduction

he Niger Delta as historically defined comprises the present Delta, Bayelsa and Rivers States in south-south Nigeria (Dike 1956;Willinks et al., 1958;Akinyele 1998). The total area is 25,640 km 2 ; Low Land Area 7,400km 2 , Fresh Water Swamp 11,700 km 2 , Salt Water Swamp 5,400 km 2 and Sand Barrier Islands 1,140 km 2 (Ashton- Jones. 1998). The Niger Delta mangrove ecosystem is the largest in Africa and second largest in the world (Awosika, 1995). It is one of the world's most fragile ecosystems (NDES, 1997) and the area with the highest fresh water fish species in West Africa (Ogbe 2005).

Oil activities started in the Niger Delta in 1908. However, commercial oil production began at Oloibiri, Bayelsa State in 1956 but oil exportation started in 1958. Presently, oil accounts for over 80% of state revenues, 90% of foreign exchange earnings and 96% of export revenues (Ohiorhenan 1984; Ikelegbe 2005; UNSD, 2009). About 2.45 million barrels is produced daily that earns the country an estimated $60 billion annually (Ploch, 2011). Over 85% of oil is produced in the Niger Delta (SPDC, 2008) mostly from the mangrove ecosystem. However, oil activities impact adversely on the marine environment (Lee and Page, 1997; Snape et al., 2001; Liu and Wirtz, 2005), with allied severe socioeconomic effects (Ibeanu, 1997;Roberts, 1999Roberts, , 2005;;Omoweh, 2005). Oil extraction impacts on ecosystems In the Niger Delta, this has been exacerbated by the oil companies' impunity of operations with no regard for the environment. As, such, oil operation have entailed recurrent oil spillages and massive gas flaring. The impunity of oil operations in the Niger Delta is exemplified by the fact that Shell operations in Nigeria that accounts for just 14% of its oil production worldwide, accounts for a staggering 40% of its oil spills worldwide (Gilbert, 2010). Oil spills records obtained from the Department of Petroleum Resources (DPR) showed that between 1976 and 2005, 3,121.909.80 barrels of oil was spilled into the Niger Delta environment in about 9,107 incidents. Independent researchers have however argued that the volume and incidents of oil spills are under reported (Green Peace, 1994; Banfield, 1998;Iyayi, 2004).

Three main mangrove species exists in Nigeria; R. Racemosa, R. mangle and Rhizophora harrisonni (Adegbehin, 1993). Two others of less abundance, Avincennia germinans and Laguncularia racemosa are also present. The mangrove is a highly productive biotope with a vigorous, rich and endemic wildlife, supporting a wide and varied group of mobile organisms ranging from birds that nest in the trees to fishes that feed and live among submerged prop roots (Odum et al., 1982). Mangroves are the most sensitive of all coastal ecosystems (Hayes and Gundlach, 1979). Hydrocarbons are major threat to mangroves (Hanley, 1992;Kadam, 1992;Tarn and Wong, 1995), as high proportions of heavy metals are retained in mangroves sediment (Tarn and Wong, 1995). The mangrove forests and creeks constitute the main areas of oil exploration and exploitation activities in the Niger Delta.

2. II.

3. Materials and Method

Water samples were collected for two years from three (3) swamp locations within the crude oil prospecting areas of the mangrove ecosystems two with high oil activities (Nembe and Okrika) and one devoid of oil activities (Okpare). The samples were collected, in January and July and analysed for their physical and chemical parameters. The samples for chemical analysis were collected in labelled sterilised plastic bottles, following APHA, 1998 (standard procedures) and transported in an ice chest to the laboratory. The samples for total hydrocarbon content (THC) analysis were placed in pre-labelled glass containers and sealed with aluminium foil. Temperature was recorded in situ using the mercury-in-glass thermometer, pH was determined using a pH meter, while dissolved oxygen (DO) and biochemical oxygen demand (BOD) were determined using the modified Winkler method and the 5 day BOD test respectively (APHA, 1998). Nitrate and salinity were determined using the Brucine and ascorbic acid methods respectively, while phosphate was determined using hand-held refractometer (APHA, 1998).

The questionnaire schedule was administered to respondents in the three communities where the sediment and water samples were collected. The questionnaires were administered to respondents (households) using the Cluster Survey method (Nachmaias and Nachmaias, 1996 and Riley, 1963), based on simple random sampling. The study population is the Niger Delta States (Bayelsa, Delta and Rivers), which account for over 75% of the crude oil production in Nigeria. The crude oil-exploration host communities in Niger Delta served as the sampling units, from which three were randomly selected for the study. The sample size is two hundred prorated based on 2007 population census (NPC, 2007) The pH of water samples from the study was acidic with mean pH ranging from 5.07±0.05-5.43±0.04 in wet season and 5.00±0.00-5.20±0.14 in the dry season (Table 1). It was observed that there was no significant difference p ? 0.05 between the values for wet and dry seasons. The presence of several metals; lead, zinc, chromium, cadmium and copper in high concentration was also, observed in the water samples. Their mean concentration was 1.77±0.11 mg/l, 2.59±0.19mg/l, 1.74±0.17mg/l, 1.76±0.18mg/l and 1.76±0.18mg/l respectively (wet season) and 1.86±0.1mg/l, 2.75±0.19mg/l, 1.78±0.14mg/l, 1.82±0.16mg/l and 1.82±0.16mg/l respectively (dry season). There was no significant difference (p ? 0.05) in the concentrations of the heavy metals across the three study sites.

4. IV.

5. Survey Results

6. Results

obtained from the structure questionnaire administered to respondents in the various study communities shows that about 77% of the respondents were of the view that mangrove wood has become scarce, while 7% said there was no scarcity of mangrove wood (Fig. 1). Figure 1 Also, respondents' response to impact of crude oil on fish catch in the shows that about 75% of the respondents held the view that there was decrease in fish catch, while 8% claimed fish catch had actually increased in the region (Fig. 2).

Figure 2 V.

7. Discussion

The water quality in an aquatic environment is very important for the survival of its flora and fauna. This is usually assessed by the pH and the heavy metal concentration in the water, which are key parameters in many ecological studies. A strong relationship exists between pH and the physiology of most aquatic organisms (Kinne, 1970). Thus, the range of pH in an environment is used to detect the impacts of pollution (RPI, 1985). The pH of the water samples in this study was acidic ranging from 5.03 in Nembe to 5.6 at Okpare with a mean of 5.29±0.29 (Table 1). The low pH observed in the water samples would seem to indicate the unhealthy nature of water in the Niger Delta region. The pH of the study, when compared to a base study report RPI (1985): 7.50-7.80; and Dublin-Green (1990): 6.90-7.60, seems to show that water quality deteriorated over the years in the Niger Delta. Water quality, as several studies have shown, has impacts on species composition, assemblages and distribution of plankton (Boney, 1983), benthos (Dance and Hynes, 1980; Jones, 1987;Hart and Zabbey, 2005) and fish (Boney, 1983;Kutty, 1987). The pH values obtained in this study are outside the 6.00 to 9.00 range, which were suggested for optimal fish production (Boyd and Lichtkoppler, 1979;Cup, 1986;Onuoha and Nwadukwe, 1987).

Several heavy metals; chromium, zinc, copper, cadmium and lead detected in the water samples (Table 1) had levels higher than the prescribed limits by WHO/ FAO (1976). The high concentration of heavy metals coupled with the low pH observed, are indicative of high levels of pollution of the Niger Delta environment. Several studies have associated the high pollution levels to oil spills from oil-related activities in the region (Kinigoma, 2001; Amusan and Adeniyi, 2005; Wogu, and Okaka 2011). Pollution from crude oil especially light crude, besides giving rise to poor water quality is a major threat to mangroves (Hanley, 1992;Kadam, 1992;Tarn and Wong, 1995). Nigeria produces mainly light crude and this has been shown to impacts more adversely on mangroves (Proffitt et al., 1997;Duke et al., 2000) than heavy crude. This is because mangroves sediment retains oil as it behaves like a sink; leading to persistence of oil on or inside the sediments (Maia- Santos et al., 2012). Thus, mangrove sediment retains high proportion of heavy metals (Tarn and Wong, 1995). This acutely impacts mangroves (Garrity et al., 1994) and disrupts the structure of mangroves habitat (Nadeau and Berquist, 1977;Jackson et al., 1989;Duke et al., 1997). The effects of oil pollution are long lasting (Corredor et al., 1990; Teal et al., 1985; Burns et al., 1993, 1994) up to 50 years (Ekekwe, 1981;Duke and Burns, 1999;Brito et al., 2009). Several studies have reported negative impacts of oil pollution on Mangroves. Duke et al. (1993) reported that oil pollution impairs the growth of mangrove seedlings, while Emuedo and Anoliefo, (2008) reported that oil impairs root growth in mangroves, leading to eventual death. Crude oil impact has both acute and chronic effects on mangroves (Jackson et al., 1989; Grant et al., 1993; Böer, 1993; Burns et al., 1993; Dodge et al., 1995; Wardrop et al., 1996). Even when oil exposure does not out-rightly kill mangrove, it severely weakens mangroves to a point where they succumb to natural stresses that they would ordinarily have survived (Snedaker et al., 1997). In addition, when trees are impacted upon by oil, there is the loss of benefits previously derived from the trees; such as nursery for fish species and prawns (Cappo, 1995a, b) or in the prevention of shoreline erosion (Furukawa and Wolanski, 1996;Duke et al., 1997).

All these have had grave implications on sustainability of the mangrove ecosystem in the Niger Delta. The mangroves ecosystem provides the major sources of economic activities and food for oil-host communities in the Niger Delta. Crabs, Oysters, Cockles and Periwinkles are easily gathered around the roots of mangroves (Ejituwu, 2003). However, oil pollution also reported that by 1999 Shell had cut over 24,000 miles of seismic lines through mangrove forests. These have resulted in huge reduction of mangroves in the Niger Delta. Indeed, a study FAO, (2005) reported that mangroves in the Niger Delta have the most rapid rate of depletion in the world. During the focus group discussions, most participants complained about mangrove wood scarcity. This view was also expressed by about 77% of the respondents of the sampled survey (Fig. 1). The loss of mangroves has implication for sustainability in the region. Studies show that mangrove loss in the Niger Delta has reduced the uses to which the wood is put and the cost prohibitive (Wilcox and Powell, 1985;Bassey, 1999;Raji et al, 2000).

Also, the mangrove ecosystem is the basic nursery for aquatic species, especially fish (Rutzler and Feller, 1987). The Niger Delta mangroves provide breeding grounds for numerous species of fin fish, prawns, and as habitat for crabs and molluscs (IPIECA, 1993). It would seem that huge loss of mangroves coupled with the poor water quality has led to reduction in fish stocks. This has correspondingly reduced fish catches significantly in the region. This is shown in the result of the sample survey (Fig. 2) where about 75% of the respondents opined that fish catches have reduced in the Niger Delta. In addition, this has resulted in the virtual extinction of some fauna in the region. Omoweh (1998) reported the virtual extinction of cat fish, manatee or sea cow, electric fish, hippopotamus and shark in the Niger Delta. Emuedo (2010) reported that iguana (Ogborigbo), edible frog (Okhere), and small red cray fish (Iku-ewhewhe) have also become virtual extinct in the region. Furthermore, poor water quality has also led to the bio-accumulation of heavy metals by common fish species found in the region; Tympanotonus

8. Conclusion

The quality of water in an aquatic environment is very important for the survival of its flora and fauna. Water quality also has a role to play in the overall health of an environment. This study showed very low pH levels as well as levels of heavy metal much higher than the WHO prescribed limits; indicating the unhealthy state of the Niger Delta environment. The incessant oil spills in the region have led to chronic pollution of the environment with much negative impacts on the mangrove ecosystem. As shown by the study, this has resulted in mangrove forests depletion, with severe consequences; scarcity of mangrove wood, reduction in fish stocks. As Sullivan et al. (2008) has asserted "for 75% of rural poor (as in the Niger Delta), across the world, access to good water makes the difference between life and death". The study has thus shown that oil activities have adversely affected water quality in the mangrove ecosystem with overall negative effects on the sustainability in the Niger Delta environment. The government and the multinational oil corporations are therefore advised to carry out proper cleanup of all subsequent oil spills and embark on a remediation of the water bodies in the region.

Figure 1.
fuscatus var radula (periwinkle) (Davies et al., 2006), Bonga Shad (Ethmalosa fimbriata) (Etesin and Nsikak, 2007), Synodontis clarias (catfish) Agbozu, et al., 2007), Shrimp (Macrobrachium felicinum) (Opuene, and Agbozu, 2008), Tilapia (Tilapia nicolitica) (Godwin et al., 2011).VI.
Figure 2. Table 1 :
1
III. Results
Parameters Nembe Okrika Okpare Grand Mean
Mean ± SD Mean ± SD Mean ± SD
pH 5.03±0.13 5.23±0.10 5.60±0.14 5.29±0.29
Sal. (mg/l) 12.98±0.43 13.05±0.44 7.90±0.14 11.31±2.95
Temp ( 0 C) 29.63±1.52 29.88±1.36 29.93±0.10 29.81±0.16
Transparency (%) 85.75±0.96 81.50±0.58 84.00±0.82 83.85±2.14
THC(mg/l) 1741.5±22.78 1883.75±24.13 1844.50±10.66 1823.25±73.47
DO mg/l 5.38±0.22 5.75±0.39 6.07±0.15 5.73±0.35
BOD (mg/l) 6.83±0.05 7.20±0.08 7.63±0.19 7.22±0.40
PO 3 ¯(mg/l) 1.41±0.03 1.25±0.06 0.83±0.10 1.16±0.30
NO¯(mg/l) 0.35±0.01 0.45±0.01 0.38±0.10 0.39±0.05
Heavy metals (mg/l)
Pb 1.77±0.16 1.84±0.07 1.83±0.10 1.81±0.04
Zn 2.88±0.13 1.78±0.16 2.49±0.09 2.38±0.56
Cr 1.87±0.07 1.74±0.03 1.62±0.09 1.74±0.13
Cd 1.77±0.04 1.86±0.13 1.70±0.04 1.78±0.08
Cu 1.91±0.07 2.65±0.13 1.61±0.09 2.05±0.54
Figure 3.
No
Don't response
know 4%
12%
Negative
opinion
7%
Positive
opinion
Figure 1: Depletion (scarcity) of 77%
mangrove wood
Increase in fish catch 7% Do not know 15% Figure 2: Impact of crude oil No response 3% Decreas e in fish catch Volume XIV Issue VI Version I
on fish catch 75%

Appendix A

Appendix A.1

Appendix B

  1. , Estuarine, Coastal and Shelf Science 38 p. .
  2. , Nigerian Journal of Botany 21 (2) p. .
  3. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate, M L Change, O F Parry, J P Canziani, P J Palutikof, C E Van Der Linden, Hanson (ed.) (Cambridge, United Kingdom
    ) Cambridge University Press. p. .
  4. Rural Nigeria: Issues in the Ogoni Crisis, (Harare
    ) 1.
  5. , American Water Resources Association 35 p. .
  6. , Sierra Book Club 267.
  7. Checkmating the Resurgence of Oil Violence in the Niger Delta of Nigeria, & L D Ojakorotu , Gilbert . p. .
  8. Evaluation of some heavy metals in Tilapia nicolitica found in selected Rivers in Bayelsa State. . J Godwin , N E Vaikosen , C J Njoku , J Sebye . Electronic Journal Environmental Agricultural and Food Chemistry 2011. 10 (7) p. .
  9. Genesis, Classification and Heavy Metal Retention Potential of Soils in Mangrove Forest. A A Amusan , I F Adeniyi . Journal of Human. Ecology 2005. 17 (4) p. .
  10. , A D Boney . Phytoplankton. Edward Arnold 1983.
  11. , A Fischlin , G F Midgley , J T Price , R Leemans , B Gopal , C Turley , M D A Rounsevell , O P Dube , J Tarazona , A A Velichko . 2007.
  12. Physico-chemical and benthic fauna of Woji Creek in the Lower Niger Delta. A I Hart , N Zabbey . Nigeria. Environmental Ecology 2005. 23 (2) p. .
  13. Engendering civil society: Oil, women groups and resource conflicts in the Niger Delta region of Nigeria. A Ikelegbe . Journal of Modern African Studie 2005. 43 (2) p. .
  14. , A O Emuedo , G O Anoliefo . 2008.
  15. , A Osuntokun . Current issues in Nigerian Environment Davidson press.
  16. Temporal Pattern in Macrobenthic Communities of the Hawksbury Estuary. A R Jones . New South Wales. Australian .Journal of Marsh and Freshwater Residue 1987. 38 p. .
  17. The Human Ecosystems of the Niger Delta. Ibadan; Krat books, Ltd, Ashton-Jones , N . 1998. p. 201.
  18. Anomalous pneumatophores and adventitious roots of Avicennia marina, B Böer . 1993. Forssk.
  19. The Mangrove Ecosystem of the Niger Delta. B H R Wilcox , C B Powell . Proceedings of a Workshop, (a WorkshopPort Harcourt
    ) 1985. University of Port Harcourt Publication Committee.
  20. Effect of Drilling Fluid Additives on the Niger Delta Environment: A Case Study of the Soku Oil Fields. B S Kinigoma . Journal of Applied Science and Environmental Management 2001. 5 (1) p. .
  21. The Rural Water Livelihoods Index: Working Paper. Food and Agriculture Organization, C A Sullivan , A Cohen , J M Faures , G Santini . http://www.fao.org/nr/water/docs/FAOW_RWLI_paper.pdf 2008.
  22. Water Quality Management in Fish Ponds. C E Boyd , F Lichtkoppler . Research and Dev. Series. No. 22. International Centre for Aquaculture 1979. p. 47. Agriculture Experimental Station (I.C.A.A), Auburn University
  23. Managing oil spills in mangrove ecosystems: Effects, remediation, restoration, and modeling. OCS Study MMS 97-0003, C E Proffitt , D J Devlin , T W Doyle . Proffitt, C.E. (ed.) 1997. New Orleans. 81 p. pp. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region (Restoration of Mangrove Ecosystems after an Oil Spill)
  24. C F Nachmias , D Nachmias . Research Methods in Social Sciences, (New York
    ) 1996. St. Martins Press. 600. (5th Ed)
  25. The foraminiferal fauna of the Bonny Estuary: A baseline study. Nigerian Institute for Oceanography and Marine Research, C O Dublin-Green . 1990. Lagos. p. 27. (Technical paper No. 64)
  26. Oil, the Nigerian State and Human Security in the Niger Delta, C O Emuedo . 2010. Nigeria. p. 298. University of Benin (Ph. D Thesis)
  27. Shell and Land Crisis in Rural: A Case Study of the Isoko Oil Areas. D A Omoweh . Scandinavian Journal of Development Alternativesand Areas Studies 1998. 17 (2 & 3) p. .
  28. Mine-water chemistry: The good, the bad and the ugly. D Banks , P L Younger , R T Arnesen , E R Iversen , S B Banks . Environmental Geology 1997. 32 p. .
  29. Marine Spill Response Corporation, D C Washington . p. .
  30. Niger Delta Economies of Violence, D Kemedi . 2005. Berkeley, USA. University of California (Working Paper No. 5. International Studies) (Oil on Troubled Waters)
  31. , D L Grant , P J Clarke , W G Allaway . 1993.
  32. Perception and Reality: Assessing Priority for the Sustainable Development in the Niger Delta. D Moffat , O Linden . Ambio: A journal of Human Environment 1995. 24 p. .
  33. The Funiwa-5 Oil Blow-out. International Seminar on the Petroleum Industry and the Nigerian Environment, E Ekekwe . 1981. Lagos: NNPC. p. .
  34. A case study of insitu oil contamination in a mangrove swamp. E M S Brito , R Duran , R Guyoneaud , M Goñi-Urriza , T G Oteyza , M A C Crapez , I Aleluia , J C A Wasserman . Marine Pollution Bulletin 2009. 58 p. .
  35. Environmental Baseline Studies for the Establishment of Control Criteria and Standards against Peteroleum related polution in Nigeria. RPI 1985.
  36. An integrated approach to development in the Niger Delta, F Iyayi . 2004. (A paper prepared for the Centre for Democracy and Development (CDD)
  37. The State, Accumulation and Violence: The Politics of Environmental Security in Nigeria's Oil Producing Areas. F N Roberts . NISER Monograph Series 1999. (17) .
  38. Environment and Livelihoods in the Niger-Delta. F N Roberts . Towards an Integrated Development in the Niger-Delta, F Kayode, S Amadi, O Bamidele (ed.) (Lagos
    ) 2005. CDD. p. .
  39. Ecophysiological Implications of Crude oil pollution on Rhizophora recemosa, G.F.W MEYER-FWTA (ed.)
  40. Water Quality Monitoring. G C Onuoha , F O Nwadukwe . Proc. Of the Aquaculture Training Programme (ATP) held in the African Regional Aquaculture Centre (ARAC), (Of the Aquaculture Training Programme (ATP) held in the African Regional Aquaculture Centre (ARAC)Aluu, Rivers State, Nigeria
    ) 1987. p. .
  41. Waste Water Reuse and Recycling Technology. G Cup . Pollution Technology Review 1986. (77) .
  42. Shell Shocked: the Environmental and Social Cost of Living with Shell in Nigeria, Green Peace International . 1994.
  43. H Willink , G Hadow , P Mason , J B Shearer . Nigeria: Report of the Commission, 1958.
  44. Survey of heavy metals in the catfish Synodontis clarias. I E Agbozu , K E Ekweozor , K Opuene . International Journal of Environmental Science and Technology 2007. 4 (1) p. .
  45. Where Vultures feast. Shell Human Rights and Oil in the Niger Delta, I Okonta , O Douglas . 2001.
  46. IPIECA (International, 48.
  47. , I Snape , M J Riddle , J S Stark , C M Cole , C K King , S Duquesne , D B Gore . 2001.
  48. Niger Delta natural resources damage assessment and restoration Project -Phase I scoping report. Iucn/Ceesp . IUCN Commission report on Environmental, Economic, and Social Policy 2006. May 31. p. 14.
  49. The distribution, persistence and effects of petroleum hydrocarbons in mangroves impacted by the "Era" oil spill. J A Wardrop , B Wagstaff , P Pfennig , J Leeder , R Connolly . Final Phase One report. Adelaide: Office of the Environment Protection Authority, 1996. September, 1992. South Australian Department of Environ¬ment and Natural Resources
  50. The corporate responsibility debate, J Banfield . 1998. November. African Business. p. .
  51. Ecological effects of a major oil spill on Panamanian coastal marine communities. J B Jackson , J D Cubit , B D Keller , V Batista , K Burns , M Caffey , R L Caldwell , S D Garrity , D C Getter , C Gonzalez , H M K Guzmman , W Kaufmann , A H Knap , S C Levings , M J Marshall , R Steger , R C Thompson , E Weil . Science 1989. 243 p. .
  52. Persistence of spilled crude oil in a tropical intertidal environment. J E Corredor , J M Morell , C E Castillo . Marine Pollution Bulletin 1990. 21 p. .
  53. , J M Teal , J W Farrington , K A Burns , J J Stegeman , B W Tripp , B Woodin , C Phinney . 1985.
  54. How many years until mangrove ecosystems recover from catastrophic oil spills?. K A Burns , S D Garrity , S C Levings . Marine Pollution Bulletin 1993. 26 (5) p. .
  55. The Galeta oil spill. II. Unexpected persistence of oil trapped in mangrove sediments, K A Burns , S D Garrity , D Jorrisen , J Macpherson , M Stoelting , J Tierney , L Yelle-Simmons . 1994.
  56. Trade and Politics in the Niger Delta, K Dike . 1830-1885.. 1956. Oxford: Claredon Press.
  57. , K Furukawa , E Wolanski . 1996.
  58. Relationships between heavy metals in shrimp (Macrobrachium felicinum) and metal levels in the water column and sediments of Taylor creek. K Opuene , I E Agbozu . International Journal of Environmental Research 2008. 2 (4) p. .
  59. Mangrove swamp communities. K Rutzler , C Feller . Oceanus 1987. 30 (4) p. .
  60. Some effects of agricultural land use on stream insect communities. K W Dance , H B N Hynes . Environmental Pollution 1980. 22 p. .
  61. Large-scale damage to mangrove forests following two large oil spills in Panama. Biotropica 29 p. .
  62. Long-term effects of oil pollution in mangrove forests (Baixada Santista, Southeast Brazil) detected using a GISbased multitemporal analysis of aerial photographs, L C Maia-Santos , M Cunha-Lignon , Y Schaeffer-Novelli , G Cintrón-Molero . 2012.
  63. Youth Militancy, Amnesty and Security in the Niger Delta Region of Nigeria, L D Gilbert . 2010. In V.
  64. Impacts of Global Climate Change and Sea level rise on Coastal Resources and Energy Development in Nigeria, L F Awosika . Umolu J.C., (ed.) 1995. Nigeria: DAMTECH Nigeria Limited. ((ed) Global Climate Change: Impact on Energy Development)
  65. Sequential negotiation in multiagent systems of oils, spill response decision-making. Baseline/Marine Pollution Bulletin, Liu , K W Wirtz . 2005. 50 p. .
  66. Nigeria: Elections and Issues for Congress, L Ploch . http://www.fas.org/sgp/crs/row/RL33964.pdf> 2011. April 1. (Congressional Research Service (RL33964))
  67. Coastal management issues in the Northern Territory: An Assessment of current and future problems. L R Hanley . Marine Pollution Bulletin 1992. 25 p. .
  68. Management and remediation of contaminated sites at Casey Station. Antarctica. Polar Record 37 p. .
  69. Bays, bait and Bowling Greenpilchards and sardines: part 1, Sportfish Australia, M Cappo . 1995a. p. .
  70. Bays, bait and Bowling Greenin-shore herrings and sardines: part 2. M Cappo . Sportfish Australia 1995b. p. .
  71. Site selection for aquaculture: Chemical features of water. Working Paper African Regional Aquaculture Centre, M N Kutty . 1987. Port Harcourt.
  72. Coastal processes field manual for oil spill assessment. Prepared for NOAA, Office of Marine Pollution Assessment, M O Hayes , E R Gundlach . 1979. 1997. Boulder, Colorado: Research Planning Institute, Inc ., South Carolina.
  73. Cadmium, Copper, Lead and Zinc Tissue Levels in Bonga Shad(Ethmalosa fimbriata) and Tilapia (Tilapia guineensis) Caught from Imo River. M U Etesin , U B Nsikak . Nigeria . American Journal of Food Technology 2007. 2 p. .
  74. Pollution studies on Nigerian rivers: heavy metals in surface water of Warri River, Delta State, M Wogu , C E Okaka . 2011. (Journal of)
  75. M W Riley . Sociological Research: Exercises and Manual, (Orlando. Fla
    ) 1963. 2.
  76. National Programme to Combat Desertification, 2005. Oxford: University Press. (FAO (Food and Agricultural Organisation))
  77. The Mangrove in the Niger River Delta. N Bassey . The oil flows, the Earth Bleeds, E B Velasquez (ed.) (Quito-Ecuador, Oilwatch
    ) 1999.
  78. Mangrove forests recovering from two large oil spills in Bahía Las Minas, Panama, in 1992. N C Duke , Z S Pinzón , M C Prada . Long-Term Assessment of the 1986 Oil Spill at Bahía Las Minas, Panama. MSRC Technical Report Series 93, 1993.
  79. , N C Duke , Z S Pinzon , M C T Prada . 1997.
  80. Dispersant use and a bioremediation strategy as alternate means of reducing impacts of large oil spills on mangroves: The Gladstone field trials. N C Duke , K A Burns , R P J Swannell , O Dalhaus , R J Rupp . Marine Pollution Bulletin 2000. 41 (7-12) p. .
  81. Women in Nigerian History: The Rivers and Bayelsa States Experience, Choba, N C Ejituwu . Ejituwu, N.C. and A.O.I. Gabriel (ed.) 2003. Onyoma Research Publications. (Andoni women in Time Perspective)
  82. Fate and Effects of Oil and Dispersed Oil on Mangrove Ecosystems in Australia. Australian Institute of Marine Science and CRC Reef Research Centre, Final Report to the Australian Petroleum Production and Exploration Association, N Duke , K A Burns . http://www.marine.uq.edu.au/marbot/publications/pdffiles/06oil232_247.pdf 1999.
  83. Mangrove soils as sinks for wastewater-borne pollutants, N F Tarn , Y S Wong . 1995.
  84. Bioaccumulation of heavy metals in water, sedimart and periwinkle (Tympanotonus fuscatus) from Elechi Creek, Niger Delta. O A Davies , M E Allison , H S Uyi . Africa Journal of Biotechnology 2006. 5 (10) p. .
  85. of the Project Conservation and Sustainable Utilisation of Mangrove Forests in Latin America and Africa Regions. International Society for Mangrove Ecosystems, O J Adegbehin . 1993. Okinawa, Japan. 3 p. . (Technical Report) (Mangroves in Nigeria)
  86. Marine Ecology, V. 1. Environmental factors, part 1. A comprehensive, integrated treatise on life in oceans and coastal waters, O Kinne . 1970. New York: Wiley-Interscience. 681.
  87. The effects of oil and chemically dis¬persed oil in tropical ecosystems: 10 years of monitoring experimental sites, R E Dodge , B J Baca , A H Knap , S C Snedaker , T D Sleeter . 95-104. 1995. Washington, D.C.: Marine Spill Response Corporation. 82 p. pp. (MSRC Technical Report Series)
  88. Petroleum hydrocarbons and their effects in subtidal regions after major oil spills. R F Lee , D S Page . Marine Pollution Bulletin 1997. 34 p. .
  89. Effects of the March 18, 1973 oil spill near Cabo Rojo, Puerto Rico on tropical marine communities. R J Nadeau , E T Bergquist . Proceedings of the 1977 International Oil Spill Conference, (the 1977 International Oil Spill Conference) 1977. p. .
  90. , R T Akinyele . 1998. (Institutional Approach to the Environmental Problems of the Niger Delta" in)
  91. Managing oil spills in mangrove ecosystems: effects, remediation, restoration, and modeling. OCS Study MMS 97-0003, S C Snedaker , P D Biber , R J Aravjo . C.E. Proffitt (ed.) 1997. New Orleans. p. . U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region (Oil spills and mangroves: an overview)
  92. Physico-chemical features of Thana Creek. S D Kadam . Environmental Ecology 1992. 10 p. .
  93. Sedimentation in mangrove forests. Mangroves and Salt Marshes 1 p. .
  94. The Galeta oil spill I. Long term effects on the structure of the mangrove fringe. S Garrity , S Levings , K A Burns . Estuarine, Coastal and Shelf Science 1994. 38 p. .
  95. Overview of SPDC Operations in Nigeria, paper presented at SPDC Oil Seminar for Academics, SPDC, (Shell Petroleum Development Company (ed.) 2008. November 5-6. Port Harcourt, Nigeria.
  96. Status of water quality in coal mining areas of Meghalaya, India. S Swer , O P Singh . http://www.indiaenvironmentportal.org Proceedings of the National Seminar on Environmental Engineering with Special Emphasis on Mining Environment I.N. Sinha, M.K. Ghose, and G. Singh, (ed.) 2004.
  97. Standard Methods for the Examination of water and Waste-water 20 th ed. APHA 1998. American Public Health Association.
  98. The response of grey mangrove (Avicennia marina (Forsk.) Vierh.) seedlings to spills of crude oil. Journal of Experimental Marine Biology and Ecology 171 p. .
  99. The West Falmouth oil spill after 20 years: Fate of fuel oil compounds and effects on animals. Marine Pollution Bulletin 24 (12) p. .
  100. Trade Profile, http://data.un.org/CountryProfile.aspx?crName=Nigeria#Economic 2009. UNSD (United Nations Statistics Division
  101. Man¬groves two years after the 1991 Gulf War oil spill in Saudi Arabia. Vierh . Marine Pollution Bulletin 27 p. .
  102. Pesticides Residues in Food Report of the 1975 Joint Meeting of the FAO Working Party of Experts on Pesticide Residues and WHO Expert Committee on Pesticides Residues. World Health Organisation, Who/Fao . Series No. 592. 1976. (Technical Report)
  103. Boiling Point: A Publication on the crises in the oil producing communities in Nigeria. Committee for the Defence of Human Rights, W Raji , A Ale , E Akinsola . 2000. Lagos. p. 242.
  104. Y S Wong , N F Tarn . Proceedings of the Asia-Pacific Symposium on Mangrove Ecosystems Rong Kong, (the Asia-Pacific Symposium on Mangrove Ecosystems Rong Kong) p. .
Home 
Date: 2014-01-15