Introduction
Gas flaring can be regarded as the release of natural gases into the atmosphere by burning of the gases in the oil fields and refineries when no other use can be made from it at that particular time.
According to Olojoba (2009), gas flaring is the burning of natural gases during exploitation. It has been a major problem in oil producing communities since the discovery of crude oil in 1956. Gas flaring gives rise to emission of several gases such as oxides of carbon, sulphur, nitrogen, hydrocarbon and gaseous particulate like smoke, soot and smog into the atmosphere. Some of these emissions are toxic to humanity depending on the amount in the atmosphere.
Apart from the economic consequences of gas flaring, is also known to have caused a lot of pollution effects on soil and vegetation. The environmental impact of gas flaring includes atmospheric pollution, dryness of the environment which results in the destruction of soil and vegetation.
According to Adebanjo (2005), when these gases are flared into the atmosphere, they react with water vapour such as rain, fog, dew and snow to form acid rain, thereby affecting microbiological processes in the soil. These acid deposits resulting from gas flaring damage the vegetation and increases soil acidity. It also decreases nutrient availability leading to low agricultural productivity and forest death.
According to the study carried out by Ngige in 2010 at Olobiri, it was observed that gas flaring greatly affected the vegetation and the soil. He further stated that during gas flaring, the pollutants released destroyed cells on the leave surfaces. They also caused stomata to open and close causing the flow of water through plants, which in turn results to excessive loss of water in plants. The emitted gas injected into the air through flaring condenses and dissolve in rain which later falls down as acid rain that consequently results to dryness of vegetation and equally affect the soil.
Conceptual framework
According to Shell Report (2009) the discovering of the black gold by Shell, brought some rays of hope particularly in the economic fortune of Nigeria. According to Ngige (2010), the aggregate of gas and particulate matter from burning of oil have began to alter the world climatic system, which immensely destroy some vital micro-organisms in the soil and equally dry up vegetation around gas flaring vicinity. Pollution due to oxides of nitrogen, sulphur and carbondioxide in the surrounding atmosphere, has immensely reduce the activities of the plants during photosynthesis and subsequent destruction of the vegetation by accumulation of flared gases on the surface of leaves which greatly obstruct the penetration of energy from the sun needed for photosynthesis.
According to Olojoba (2009), the effect of gas flaring is the damaging effect on the environment and economic wastage. The problem of gas flaring has long been a major source of conflict between oil companies and the need for proper evaluation of the problem created is of paramount importance. Flaring of gas give rise to the emission of dangerous gases such as oxides of carbon, sulphur, nitrogen, unburnt hydrocarbons and gaseous particulates like smoke, soot and smog. The combination of some of these gases under certain condition gives rise to air pollution problems and thus adverse effect on soil, human, animals, plants and general degradation of the environment.
No doubt oil exploration has come to stay in Nigeria, but suffice to say that its significant increasing environmental pollution must be unacceptable. In this regards, health education of all and sundry cannot be overemphasized and should be a variable tool in controlling the attendant environmental degradation associated with gas flaring. Technology is also essential in helping to reduce pollution level below the danger point which can be achieved by knowing the amount and pattern of production and consumption.
Sources of gas flaring
The following are the sources of gas flaring:
- Well test flaring.
- Refineries sources
- Gas flow station sources
- Solution gas flaring
- Natural gas battery and pipe flooring
Well test flaring
This occurs during drilling and test of oil gas field. It determines the types of fluid a well can produce and also the pressure and flow rate and other characteristics of the underground reversion. It also determines the economic values and the types of facilities to be used.
Refineries sources
These are companies which produce or process crude oil into fuel, kerosene, diesel and others. During the processing, combustion of bye products of gas waste is released into the atmosphere through chimney and pipes work construction.
Gas flow station sources
Plant equipment items are ever pressured. The pressured relief valves on the equipment automatically released gasses (sometimes liquids) as which is routed through large piping runs called flared headers connected to flare stocks or chimney. The released gases or liquids are burned as they exit the flare stock or chimney. However, all the sources flare common pollutants into the atmosphere. These include sulphur dioixide, nitrogen dioxide, carbon monoxide, hydrocarbons and particulate matters which causes environmental hazards and ozone layer depletion (Ejime, 2006).
Solution gas flaring
This is the disposal of natural gas produced along with oil and bitumen and occurs at facilities called batteries where productions from one or more wells are processed and store. It is the most common type and account for three quartered volume of gas flared in Nigeria.
Natural gas battery and pipe flaring
This has to do with flares at production with compressor gathering pipelines and facility dehydration occur during emergencies, maintenance, shut down, equipment failures and upset condition.
Effects of gas flaring
The effects of gas flaring can be categorised into:
- Effects on soil
- Effects on vegetation
- Effects on human health
- Effects on materials
Effects on soil
According to Chijoke (2006) in collaboration with Olorunda (2007) observed that gases flared into the atmosphere condense and dissolve in rain which later fall down as acid rain that consequently result to pollution of agricultural land. He further observed that when acid rain falls, it causes reduction of soil pH value to acidity and this consequently has effect on the activities of aerobic micro-organisms in the soil. The acid rain, which results from gases, flared affects the soil constituent by drying up its soil nutrients, e.g. calcium, phosphate, sodium, etc. He further stated that the soil constituent consist of mineral matter, soil water, humus, air and living organisms. The acid rain which percolates into the soil dries up these matters. During gas flaring, soil water is consequently affected.
According to Emueze (2011), the soil fertility and productivity are equally affected. This accumulate in rendering the soil unsuitable for adequate plant production and plant growth due to loss of soil nutrients leading to bare soil surface which enhance activities like soil erosion leaching, run-off, excessive flooding, etc.
According to Albert (2006), in its article stressed that acid rain from flared gas affects the soil by causing variation in soil acidity which affect the mineral salt uptake by plants. He went on to say that a reduction in soil fertility and productivity makes agricultural production impossible.
Effects on vegetation
According to Okoye (2013), it was observed by him that gas flaring greatly affects the vegetation by drying up of plants crops around flow stations during gas flaring. He further to observe that during gas flaring soot, oxides of sulphur and nitrogen that are released destroy cells on the surface of the leaves.
According to Uchegbu (2006), destruction of vegetation and crops usually occur in the vicinity of oil producing communities; this is because, the gases such as methane, chlorofluorocarbon, nitrogen oxides, etc. flared dries up the crops and plants.
It was observed further by Uchegbu (2006) that the gases flared into the air emits huge amount of carbon monoxide and methane from the flow station and pollute the air in the oil producing communities; by and large the entire globe. It retarded the development and the ability of plant to store products e.g. sugar during photosynthesis in the leave and cause discolouration of leaves and death of plants. Gas flaring suppresses growth and flowering plants, hence poor growth of vegetation which might lead to death of plants and loss of vegetation.
According to Olorunda (2009), during gas flaring, the gases flared settles on surface of the leaves thereby affecting the cuticle, which prevent the leaf from losing too much water. He further stated that when the cuticle is affected by the flared gas, the plant would then experience an excessive evaporation which results to dryness of the plants. He went on to say that chloroplast which contain a mixture of several pigment such as chlorophyll and xanthophylls which absorb certain portion of visible light used to drive the photosynthetic process.
According to Oke (2008), the gases released during gas flaring penetrate into the cell membrane of the plant cell thereby reducing selective permeability of the plant. This process gives rise to evaporation of water through the plant leaf.
According to Albert (2006), direct exposure to toxic level of oxides result to discoloration in leave and necrotic spots development. Ethylene as one of the gases release during gas flaring act on the metabolic hormones of plant and disrupt normal pattern of growth and development.
According to Luoma (2011), sulphur oxide, fluorine compounds and smog cause the reduction in photosynthesis and plant respiration. Sulphur dioxide can cause necrosis of cotton leaf, wheat, barley and apples are particularly sensitive to sulphur oxide injury. Fluoride damage is seen in many fruit trees.
From the sources above, it therefore shows that the activity of gas flaring in Afiesere Community has lead to economic implications such as increase in the rate of discoloration of material and fading plant. The buildings and cultural properties are subjected to weathering and decay under the action of acid precipitation. Other challenge facing the people of Afiesere Community is the noise pollution. The community suffers from the heat noise and vibration from flaring.
This noise effects that the community is facing can be categorized into four which are annoyance, disruption of activities, partial or total loss of hearing and mental deterioration. The continuous exposure from industrial high sound level of the machines from the gas flow station cause loss of hearing, destruction of microbic hair cells in the ear that transmit sounds.
Effects on human health
According to Olojoba (2009), the destruction of the ozone layer in the atmosphere by gases has resulted to an increase of cancer. Carbon (iv) oxide and methane are among gases emitted into the atmosphere during gas flaring. They are pollutants that act as a pungent irritant gas flaring. They are pollutants that act as a pungent irritant gas on the upper respiratory tracts. Under moderate exposure could lead to the damage of the respiratory system. The depletion of the ozone layer by gases such as methane, carbon (iv) oxide, NO2, nitrogen oxide leads to more ultraviolet radiation from the sun which consequently result in skin cancer. Reports indicated that cardiovascular diseases are more likely to occur in people that are exposed to severe weather stress from extreme heat. In addition, in many areas of the tropics, a large number of persons are still subject to diseases which are related closely to the influence of the hot humid climate. Suspended particles arising from gas flaring aggravate diseases such as bronchitis and asthma. Illness commonly known as “internal heat” is caused by long exposure to radiant heat from gas flares and high incident of birth defects and cancer is also associated to increasing amount of potentially harmful gas and particles being emitted into the atmosphere resulting to damage of human health and environment thereby causing acute respiratory tract (ART) infection in the developing world that can easily result to ill health condition and death.
Effect on materials
According to Olojoba (2009), gas flaring increases the rate of deterioration of materials such as discoloration of materials and fading of plants, damage to monuments and structures etc. Building materials and cultural properties are subject to weathering and decay under the action of acid precipitation, wind and solar radiation. Acid deposition and its precursors can however accelerate the aging of materials and building and cause secondary effects.
Reasons for gas flaring
Notwithstanding the above numerous important natural gas, it is still being practice due to the following reasons:
- Gas consuming industries are far from gas well: There are no enough industries which utilizes gases that are found within the economic distance to the source of gas oil well so as to utilize the gas.
- Lack of adequate storage facilities such as depleted hydrocarbon reservoir or other sub-surface geological features to store the unused natural gas.
- Lack of adequate gas gathering and treatment facility: Nigeria gas wells are distributed all over the Niger Delta region with no adequate gas gathering facilities to link the entire wells like in Saudi Arabia
- High cost of gathering and transmission facilities: The high investment involved in acquiring and installing gas gathering and transmission facilities discourage the explorers from installing such facilities in all their gas wells
(Olojoba, 2009)
Measures to combat gas flaring
- All oil companies in Nigeria, particularly around the Niger Delta region should be compelled to abide by the World Environmental Standards as they carry out their businesses.
- The existing air pollution laws and regulations in relations to environmental protection in Nigeria should be adequately enforced to prohibit or reduce the amount of gases from spreading into the atmosphere.
- The statutory provision (law) in the form of prescribed sanctions such as fines, imprisonment or damage to be enforced.
- The government should conduct Baseline Studies (BLS), Environmental Planning and Aesthetics (EPA), Environmental Impact Assessment (EIA), Post Impact Studies (PIS) and Environmental Evaluation Report (EER). These studies will help to put in place effective system for pollution control.
- All equipment used in oil and gas exploitation should be modernized and a proactive maintenance culture established for aging and corroding pipes source.
(Olojoba, 2009).
References
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