Oil Spillage and Associated Challenges on Aquatic Organism
Abstract
In a world with increasing crude oil production, oil spill accidents cannot be neglected when addressing pollution issues. The availability of crude oil constituents in the environment has posed serious threats to the marine community. Even biodegraded byproducts have also been discovered to be toxic to animals hence the need to know the impacts and future remediation methods. Marine organisms such as vertebrates and invertebrates are known to be affected by PAHs from the free floating embryo and larvae to their sexually matured adults. Impacts from lethal to sub-lethal dose of PAHs include habitat destruction and loss, mass mortality, impaired physiological functions such as reduced feeding, growth and development, respiration problems, loss of locomotion, balance and swimming. Most of these marine organisms take very long periods to recover and some never recover from these impacts which in tend affect the overall health and serenity of the marine environment. This paper seeks to review the lasting impacts of these spills on marine life and possible remediation methods.
1.1 Background to the Study
The marine environment has been continuously threatened by oil spills in spite of the essential technical developments in the safety of extraction and transport of crude oil and gas. These spills pose and cause severe and decade long havoc on marine and coastal ecosystems and the organisms that sustain them. Within the period of 2010-2014, 5,000 tons of the average 10,000 billion tons of crude oil transported by sea yearly was spilled due to accidents, cleaning operations or other causes. For example, washing ballast tanks account for 36,000 metric tons (11.2 million gallons) of oil entering the oceans globally every year; human induced activities and non-tank vessels. Although natural seeps releases oil into the marine environment, the oil is mostly released at low rates to which deep sea organisms are adapted to unlike the unexpected swift discharge of large quantities that occur during an oil spill or extraction accident .
Oil Spillage and Associated Challenges on Aquatic Organism
The enhanced technical standards for oil production has reduced large spills (which ranges from 7-700 tons and above 700 tons of oil) drastically during the past decades to an average of 5.2% for the 7-700 tons and 1.8% for those above 700 tons per year, whiles smaller spills (less than 7 tons of oil) representing an estimated 80% of all recorded spill has been going unnoticed and unreported. The concentration of dissolved and dispersed hydrocarbons that marine organisms are exposed to is highest during initial stages of the spill.
Hence the major toxicity mechanisms for smaller spills are from immediate exposure which disappears from sight during the first few days without the oil been necessarily degraded from the sea surface . According to Brussaard et al. measurements on the ES-2009 spill specified that slick concentration and dissolved oil compounds were high and spread from the water body and travelled directly underneath the slick to distances of at least 500 m from the spill even though slick was not visible after ~20 h. They also discovered that the dissolved oil components were available immediately to the biota in the earliest spill samples (2 h and 6 h after the spill). These data helps conclude that accidental oil availability even in smaller quantities in the marine ecosystem is of much concern and hence studies on the impact of oil spills on marine organism needs to be assessed . Also rising demands for marine oil exploration is likely to increase rather than decrease hence an increased frequency of small spills. Various researches has documented oil toxicity at its highest during the initial stages of a spill hence even smaller spills can possibly cause prolonged impacts and pose a serious risk to marine ecosystem health and biota.
For instance, major shipping routes on the North Sea is recurrently contaminated with oil, either from unintentional spills or maybe from natural oil and gas seeps discovered a lot of unsupervised and undocumented spills within the major shipping routes on the North Sea.
Even though some of these spills were small and not visible on the surface water, they release very high C30-C38 concentrations (above 80 µg/l), significant alkane and PAH levels (20-60 µg/l) and showed high toxicity values. The marine ecosystem comprises of various animals from microorganism, vertebrates (fish, birds, mammals, and turtles), and invertebrates (copepods, mollusks, crustaceans, and echinoderm). These organisms are exposed to various degree of impact during an oil spill accident. Various research have detailed the toxicological effects of oil (such as increased mortality or as sub-lethal injury, impaired feeding and reproduction and avoiding predators) on fish communities , estuarine communities, mammals, birds and turtles , deep-water corals , plankton , foraminifera , and microbial communities . This paper seeks to review the various toxicological effects of oil spills on the marine vertebrates and invertebrates.
1.2 Statement Of The Problem
Over the years oil spillage has been causing a lot of damage to lives of man, animals and even aquatic organism in the water. The natural environment is the total aggregate of all external and tangible dimensions that affect the development of living things. These include the air we breathe, biosphere, hydrosphere the soil and the water. There are other subsystems connected to the wider eco-system that contribute to the sustenance of an interconnected global system.
Oil Spillage and Associated Challenges on Aquatic Organism
Oil spillage causes gross chemical and biological impairment to plants and animals; and contributes to ecological changes as a result of deleterious or toxic effects on community members (Kafada, 2012). It can promote unintended genetic effects amongst other harmful physiological and biological consequences. Also, the social economic downsides associated with oil spillage are very significant. However, it can be mitigated and prevented by a complement of policy, technological, engineering, scientific, regulatory and legal interventions.
1.3 Objectives Of The Study
The main objective of this study is to examine oil spillage and associated challenges on aquatic organism. The specific objectives include:
- To examine the impact of oil spillage on aquatic organism
- To also access the effect of oil spillage on the economic development of Nigeria
- To also examine the causes of oil spillage
- To also examine the associated dangers of oil spillage on aquatic organism health