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Cite this article as:

 

Ahmed, I., Ali, A., Sarma, R., Gogoi, R.,  Hussain,I.,  Nath, S. and Firdousie, N. (2021) Impact of Oil Spill on Aquatic Environment. Food and Scientific Reports. 2 (9) 37-39.

ABSTRACT

In respect of the aquatic environment, oil spills are of grave concern. The oil spill devastates water, destroys organisms, endangers public health and negatively impacts the economy. Accidental release of crude oil to the aquatic environment due to anthropogenic activities pose a life-threatening impact on aquatic flora and fauna by causing serious environmental hazards, which in the course of time may lead to long-term ecological risk and ecosystem disturbance. Though there is tremendous technical growth of safety mechanisms for extraction and transportation, oil spills are occurring regularly in marine water. These oil spillages are wreaking decadal havoc on marine organisms and the ecosystem there off.

Keywords: crude oil, ecosystem, environment, organisms, impact

An oil spill is an unintentional release of liquid petroleum hydrocarbons into the environment due to human activity or natural disaster usually associated with unexpected blowouts of liquid and gaseous hydrocarbons from the well as a result of encountering zones with abnormally high pressure. When oil spills in water, it initially spread on the surface water, depending on its relative density and composition. The oil slick formed may remain cohesive or may break up in the case of rough conditions. Waves, water currents, and wind may carry the oil slick to large areas. Accidental release of crude oil into the aquatic environment due to anthropogenic activities pose a life-threatening impact on aquatic flora and fauna by inflicting serious environmental hazards, which in the course of time may lead to long-term ecological risk and ecosystem disturbance. The injuries to the ecosystem and wildlife caused by oil spills depend on location, quantum and type of oil. In the marine environment, tankers accidents and leakage of oil pipes contribute to the lion’s share of the oil spill (Mansir & Jones, 2012). The Exxon Valdez oil spill in 1989 at Prince William Sound, USA was the resultant of a tanker accident that spilled over 11 million gallons of crude oil into the environment, the largest of its kind in the USA. Though there is tremendous technical growth of safety mechanisms for extraction and transportation, oil spills are a regular phenomenon. In the year 2020, three oil tanker accidents took place that relased over 700 metric tons of crude oil (Sönnichsen, 2021). These oil spillages are wreaking decadal havoc on marine organisms and the ecosystem there off. The oil spill in the marine environment arises from tankers accidents, clearing of tankers or from a blown-out wellhead under the sea. The spread of oil into the water depends on the prevailing environmental conditions of the sea, temperature and nature of the oil itself.

 Crude oil toxicity

The crude oil is a mixture of organic compounds which consists of hydrocarbon and other molecules such as sulphur, nitrogen, oxygen with heteroatoms (Tissot & Welte, 1984). The different hydrocarbons that form the crude oil have different molecular weights and structure compounds such as methane gas, tar, resins, waxes, bitumen, etc. These hydrocarbons may vary from a small unstable monocyclic aromatic hydrocarbon such as benzene, ethylbenzene, toluene, xylene etc. to large non-volatile polycyclic aromatic hydrocarbons (PAHs) like naphthalene, anthracene, phenanthrene etc. These petroleum components cause lethal and sub-lethal effects to aquatic life forms. The toxicity of these compounds on organisms depends on a multitude of factors such as oil composition and characteristics, condition, exposure route, bioavailability, solubility etc. (Saadoun, 2015). The polycyclic aromatic hydrocarbon (PAH) is more detrimental because of persistence and non-volatility. Monocyclic aromatic hydrocarbon due to their explosive nature are less likely to accumulate in the water, sediments, organisms’ tissue level and thus less persistent (Neff, 2002). The PAH seems to be more toxic due to its ability to bind with DNA and protein less solubility and persistence causing the long-term chronic effects on organisms (Lin & Tjeerdema, 2008).

Impact of oil spill

Impact of oil spill on Environment

Aquatic habitats like coral reefs, mangroves, tidal flats, beaches (rocky, sandy) etc are an integral part of the aquatic environment which supports millions of species of fish, shellfish, echinoderms, turtles, polychaetes, plankton etc. The oil spill can seriously destroy these habitats through physical and chemical effects and alterations. The physical alteration may result from the smothering effect to the organisms, substratum or water column by the oil compounds. Chemical effects may arise due to the rise in the concentration of toxic aromatic hydrocarbon compounds which pose lethal and sub-lethal effects on organisms at different trophic levels. Oil-soaked soil may cause a devastating impact on benthos organisms such as mollusks, crustaceans, etc. The deepwater horizon oil spill, 2010 at the Gulf of Mexico, spread over at 1100- 1300 m depth had contaminated 2100 km stretch of shoreline encompassing beaches, tidal marshes, wetlands and estuaries, important breeding, nursery and feeding grounds for a vast number of aquatic organisms. The deepwater horizon spilled over 3.19 million barrels roughly 500,000 crude oil and in addition, a substantial amount of hydrocarbon gases over a period of 87 days to the environment wreaking havoc on organisms killing thousands of mammals and sea turtles by contaminating the habitats (Beyer  et al., 2015).

Impact of oil spill on Organisms

Aquatic organisms such as mammals, fish, birds are likely to be affected by oil spills in many different ways – direct contact with oil, toxic effects of hydrocarbon compounds, destruction of critical food resources etc. Mammals are subject to hypothermia in cold climates while exposed to oil. Englehardt (1982) in his study found that polar bears, seals, pinnipeds were highly affected as evident from the eye and skin lesions due to exposure, uptake to distribution and accumulation of oil compounds in fat tissue through ingestion leading to chronic health-related issues. In birds, the oil components cling to their plummage leading to improper insulation and subsequent heat loss. Moreover, oiled birds become more susceptible to death as the oil slick makes the bird too heavy to fly or find food resources and thus fall prey to predators. The Sea Turtle is regarded as the most vulnerable to oil compounds through ingestion of oil-fouled food resources, inhalation of volatile toxic compounds, physical impairment due to heavy oiling, a number of physiological alterations upon exposure (Shigenaka, 2003; Witherington, 2002). The Exxon Valdez oil spill in the USA (1989) had oiled 1400 miles of beaches, killing more than 3, 00000 birds and 2600 sea otters (McGraw Hill Company, 1999). The oil compounds can impact fishes through ingestion, absorption, and inhalation and may give rise to several health problems. The direct impact on organisms can be seen from causing changes in behaviours like changes in the foraging area, migration to other safe and suitable areas, changes in the time of foraging periods to killing fishes or contaminating the critical resources in the food chain. However, the degree of impact and harm caused by oil exposure depends upon various biological factors like age, size, and overall health of the organism. The death of fishes may be attributed to the fact that oil may form a layer of film over the gill filaments and prevent the gaseous exchange between body and surrounding environment leading to suffocation or due to lethal and sub-lethal effects of oil components to organisms. In general, eggs, larvae, and early juvenile life forms are more vulnerable to sub-lethal and lethal effects of oil. An oil spill can kill fish or cause sub-lethal damage to fish eggs and larvae like morphological deformities, reduced feeding and growth rates, increase vulnerability to predation and starvation (Sorhus et al., 2016; Hicken et al., 2011), loss of hatching ability of eggs, fouling of gill structures, impaired growth, respiration, reproduction (Balckburn et al.,2014). However, the impacts are more prominent in the early stages of eggs and larva due to the underdeveloped membrane, body and detoxifying structures (Bellas et al., 2013; Langangen et al., 2017).

 

Conclusion

When considering the impact of the oil spill on the aquatic environment, it is essential to know the amount and duration of exposure to oil as well as the components and comparative toxicity of the particular oil compounds that are present. However, the occurrence at crtitcal time may cost the organims ie. during breeding season. For eg. fishes generally breed during monsoon months. Even though the fishes succeed in spawning, the chance of hatching from eggs and larval survivability will be very less as the eggs and larvae are more vulnerable due to their underdeveloped membrane and body structure and detoxifying structures to PAHs even at lower concentrations. However, the exposure of a species of a population to an oil spill will determine the harm caused to a population as a whole based on their reproductive states at the time of the oil spill.

Reference

Bellas, J., Saco-Álvarez, L., Nieto, Ó., Bayona, J. M., Albaigés, J., & Beiras, R. (2013). Evaluation of artificially-weathered standard fuel oil toxicity by marine invertebrate embryogenesis bioassays. Chemosphere, 90(3), 1103-1108.

Beyer, J., Trannum, H. C., Bakke, T., Hodson, P. V., & Collier, T. K. (2016). Environmental effects of the Deepwater Horizon oil spill: a review. Marine pollution bulletin, 110(1), 28-51.

Blackburn, T. M., Essl, F., Evans, T., Hulme, P. E., Jeschke, J. M., Kühn, I., ... & Bacher, S. (2014). A unified classification of alien species based on the magnitude of their environmental impacts. PLoS biology, 12(5), e1001850.

Engelhardt, F. R. (1982). Hydrocarbon metabolism and cortisol balance in oil-exposed ringed seals, Phoca hispida. Comparative Biochemistry and Physiology Part C: Comparative Pharmacology, 72(1), 133-136.

Hicken, C. E., Linbo, T. L., Baldwin, D. H., Willis, M. L., Myers, M. S., Holland, L., ... & Incardona, J. P. (2011). Sublethal exposure to crude oil during embryonic development alters cardiac morphology and reduces aerobic capacity in adult fish. Proceedings of the National Academy of Sciences, 108(17), 7086-7090.

Langangen, O., Olsen, E., Stige, L. C., Ohlberger, J., Yaragina, N. A., Vikebø, F. B., ... & Hjermann, D. Ø. (2017). The effects of oil spills on marine fish: Implications of spatial variation in natural mortality. Marine Pollution Bulletin, 119(1), 102-109.

Lin, C. Y., and R. S. Tjeerdema. "Crude oil, oil, gasoline and petrol." Ecotoxicology (2008).

Mansir, N., & Jones, M. (2012). Environmental impacts of marine oil spill; a case study of Deepwater Horizon oil spill at the Gulf of Mexico United States of America 2010 (a review). Chemsearch Journal, 3(2), 64-70.

Neff, J. M. (2002). Bioaccumulation in marine organisms: effect of contaminants from oil well produced water. Elsevier.

Saadoun, I. M. (2015). Impact of oil spills on marine life. Emerging pollutants in the environment-current and further implications, 75-104.

Shigenaka, G., & Milton, S. (2003). Oil and sea turtles: biology, planning, and response. National Oceanic and Atmospheric Administration, NOAA`s National Ocean Service, Office of Response and Restoration.

Sørhus, E., Incardona, J. P., Karlsen, Ø., Linbo, T., Sørensen, L., Nordtug, T., ... & Meier, S. (2016). Crude oil exposures reveal roles for intracellular calcium cycling in haddock craniofacial and cardiac development. Scientific Reports, 6(1), 1-21.

Sönnichsen N. West Texas Intermediate crude oil prices from 2012 to 2021. Statista2020.

Welte, D. H., & Tissot, P. B. (1984). Petroleum formation and occurrence. Springer-verlag.

Witherington, B., Hirama, S., & Hardy, R. (2012). Young sea turtles of the pelagic Sargassum-dominated drift community: habitat use, population density, and threats. Marine Ecology Progress Series, 463, 1-22.

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