DETERMINATION OF THE LEVELS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) AND HEAVY METALS IN SOILS AND PLANT FOOD CULTIVARS FROM SOME OIL EXPLORATION COMMUNITIES OF BAYELSA STATE

CHAPTER ONE 

1.0 INTRODUCTION 

This research is on DETERMINATION OF THE LEVELS OF POLYCYCLIC AROMATIC HYDROCARBONS (pahs) AND HEAVY METALS IN SOILS AND PLANT FOOD CULTIVARS FROM SOME OIL EXPLORATION COMMUNITIES OF BAYELSA STATE. Crude Oil has had profound impact on the world civilization than any single natural resource   in recorded history. Oil has become a very decisive element in defining the  politics,  rhetoric and diplomacy of states. All over the world, the lives of people are affected and destiny of nations has been determined by the result of oil explorations. Oil keeps the factories of the industrialized countries working and provides the revenue, which enables oil exporters to execute ambitious national and economic development plans.   The march of progress would    be retarded and life itself would be unbearable if the world is deprived  of oil that  is why oil  has become the concern of government, a vital ingredient of their politics and a crucial factor   in the political and  diplomatic strategies (Pyagbara, 2007).

Nigeria  joined  the  league  of oil producing  nations  on  August  3rd, 1956  when oil  was discovered in commercial quantities at Oloibiri in Bayelsa and today ranks as the leading oil  and  gas producer in Africa and the 6th  largest oil exporter in the world  (Pyagbara, 2007). As  oil was struck in commercial quantities in Nigeria, it also signaled the beginning  of  a  profound  transformation of Nigeria’s  political and  economic  landscape.  Since  the 1970s, oil has accounted for 80% of the Nigerian government’s revenue and  95%  of  the  country’s export earnings. Interestingly almost all of Nigeria’s oil and gas  resources  come  from  its Niger delta region occupied by mosaic of indigenous nationalities. Crude oil is made  of different fractions and when there is spill on the environment, spreading immediately takes place, the gaseous and liquid components evaporate, some get dissolved in water and even oxidized and yet some undergo bacterial changes and eventually sink to the bottom by gravitational action (Akpofure et al., 2000). Mangrove  forests  have  fallen to  the  toxicity of oil spills, the rainforest has fallen to the axe of oil companies, wild life and game have been driven away and farmlands have been rendered infertile with gross implication on the right to adequate food (Pyagbara, 2007; Omofonmwam and Odia,  2009).  During  oil  spills  the  process of photosynthesis which enhances plant diversity is impaired since the process  is reduced because spilled crude have a high absorbance property of UV  light  which  makes  plant leaves not to photosynthesis and thus die leading to biodiversity loss (Nwilo and  Olusegun,2007).

The toxic crude affects not only the herbs and shrubs but also the soil fauna. The  volatile lower molecular weight components of the crude affects aerial life, while the  dissolution of the less volatile components which makes water toxic affects aquatic life (Akpofure et, al., 2000). Gaseous and particle-bound polycyclic  aromatic  hydrocarbons  (PAHs) are transported over long distances before deposition and may  accumulate  in vegetation (Tuteja et al, 2011). Heavy metal contaminants  of crude  oil contaminate the  soil and water and thus enter the food chain. In this manner humans are  indirectly exposed  to  PAHs and heavy metals through the food chain.

1.1 Statement of the problem

The most profound and adverse impact of oil pollution in Niger Delta is environmental  pollution with far reaching implications on all other aspects of traditional lifestyles and livelihood of the people among which is the total loss of biodiversity  and  destruction  of habitats largely due to soil degradation and persistence of  recalcitrant  hydrocarbon  constituents in water bodies, soil and food cultivars.

1.2 Aim and Objectives of the study

Nigerian crude oil contains gaseous and particle-bound polycyclic aromatic hydrocarbons as well as some heavy metals that pollute drinking water and marine organisms. These toxicants may be passed up the food chain and become a major source of   human exposure.

1.2.1 Aim of the study

The aim of this study is to determine those recalcitrant polycyclic aromatic hydrocarbon fractions preponderant in soils following episodic oil spillage events as well as the accompanying heavy metal pollutants and  how they impact on food  cultivars.

1.2.2 The Objectives are

1. To  ascertain the  different  recalcitrant polycyclic aromatic hydrocarbons that  predominate  in soils following episodic oil spillage event.
2. To establish to what extent those recalcitrant PAHs are taken up by food cultivars which   as primary producers introduce them into the food  chain.
3. To determine the heavy metal pollutants  accompanying these episodic oil spillage events  in the soil and how they join the food chain through uptake  by.
4. To determine if there are any correlation in the preponderance of PAHs, heavy metals and b/w PAHs and heavy metals.

1.3 Significance of the study

The overwhelming environmental impacts of oil exploration  activities  and  accidental  oil  spills abound in literature. However, the actual exposure in the Niger Delta environment and food chain has  remained  an object of  controversy as there are  claims that the toxic fractions  of crude oil are very volatile and evaporate easily from the environment. This study will document the exposure risk of the population to PAHs  and  heavy  metals  by determining those recalcitrant pollutants that occur in soil in the crude oil spill and how they impact on  food cultivar.

1.4 Relevance of the study

Public perception of economic issues in recent times has clouded some very important issues concerning the impact of oil exploration and exploitation on the ecology and people of Oporoma and Angiama in Niger Delta.The result of the  study  will  provide  sufficient  empirical basis for the community to seek for proper compensatory redress while at the same time guide government to make informed policy formulation for the protection of the Niger Delta environment from the hazards of oil prospecting  activities.