Friday, October 3, 2014

Hydrocarbon Pollution

The bulk of newly discovered petroleum reserves and the best prospects for future discoveries, lie not on land, but under water. Hence, the oil and gas industry began to move offshore. They first moved into shallow water and eventually into deepwater, where technological advances have opened up vast new reserves of oil and gas in remote areas. Drilling in deepwater brings new risks because the drilling rigs are potentially dangerous machineries and the deepwater environment is cold, dark, distant, and under high. (Graham, et al., 2011)

One of the catastrophic oil spills is the Deepwater Horizon oil spill. Deepwater Horizon (oil rig) was drilling the Macondo well under 5,000 feet of Gulf of Mexico, and then over 13,000 feet under the sea floor to the hydrocarbon reservoir below. (Graham, et al., 2011) On the evening of 20 April 2010, a gas release and subsequent explosion occurred on the Deepwater Horizon oil rig working on the Macondo exploration well for BP in the Gulf of Mexico. (Deepwater Horizon accident and response) The estimated oil spill is approximately 206 million gallons. (Ramseur & Hagerty, 2014)

Figure 1 Explosion of Deepwater Horizon drilling rig in the Gulf of Mexico
Source: (THOMPSON, 2013)

Methods for cleaning up the oil spill:
Chemical:
Dispersants are chemical formulations composed of solvents, surfactants and other additives that disrupt the solid surface of an oil slick by reducing the surface tension between oil and water. Composed of molecules with a water-compatible (hydrophilic) end and an oil-compatible (lipophilic) end, dispersant link an oil droplet to nearby water molecules and allow the natural agitation caused by waves and wind to pull the droplets apart into increasingly smaller droplets. (Graham P. , 2010)

Figure 2 Applying of dispersant by aircraft
Source: (Help NOAA Research Chemical Dispersants and Oil Spills, 2014)

Boom:
Booms are floating, physical barriers to oil, made of plastic, metal, or other materials, which slow the spread of oil and keep it contained. (Spill Containment Methods, 2014)
Boom may be towed behind boats to collect oil. Oil collected can either be skimmed from the water surface, or towed away from the main slick to a location where it is safe to burn it. There are different types of boom: (1) Hard boom is typically made of PVC or similar durable material that consists of an inflated chamber that rides above the water, and an attached skirt that hangs down into the water. (2) Fire boom is similar in design to hard boom, but is made of material that can withstand the heat generated by burning oil. (3) Sorbent boom is constructed of a long fabric sock enclosing material that attracts oil but repels water. It does not have an attached skirt and once saturated with oil, sorbent boom must be removed and properly disposed of. (National Oceanic and Atmospheric Administration, 2010)

In situ burning:
In situ burning of an oil slick, or part of a slick, before it reaches the coast. Responders will corral some of the oil from the slick in a fire-proof boom, and then ignite it. (Office of Response and Restoration, 2014)
Burning of collected oil difficult or unachievable beyond the first 12 – 24 hours after it is spilled, because the oil may also emulsify and evaporation may remove most of the burnable components. Slick thickness is so important for on-water burning because very thin slicks are rapidly cooled by loss of heat to the underlying water and unable to form oil vapour for burning. (MICHEL, SCHOLZ, WARREN JR., & WALKER, 2005)

Figure 3 Fire containment boom and in-situ burning
Source: (Summit Contracting, 2011)

Skimmers:
Skimmers are slow yet very effective machines used for surface removal in calm or sheltered waters and along shorelines. They work by taking advantage of the adhesive nature of the oil. Using rotation, suction, gravity or other forces to drive motion, these machines: 1. provide a never-ending surface for the spilled petroleum to cling to, 2. clean the surface, and 3. repeat that process continuously. (Graham P. , 2010)

Figure 4 Example of skimmer
Source: (Philips, 2010)

Bioremediation:
Bioremediation is the use of microorganisms, plants or fungi to correct a contaminated or altered environment. Many scientists agree that naturally occurring bacteria capable of degrading oil are already present in marine environments but the limited availability of nutrients like nitrogen and phosphorus prevent the oil-eaters from performing to their full potential. (Graham P. , 2010)
There are two main approaches: (1) Bioaugmentation, in which oil degrading bacteria are added to supplement the existing microbial population and (2) biostimulation, in which nutrients or other growth limiting co-substrates (e.g. nitrogen and phosphorus) are added to stimulate the growth of indigenous oil degraders. (Venosa)

Impact to the environment:
Physical smothering of organisms:
This is caused by oils with a high viscosity, in other words heavy oils. Smothering will affect an organism’s physical ability to continue critical functions such as respiration, feeding and thermoregulation. (Environmental Effects of Oil Spills)
For example, oil coated birds' feathers, causing birds to lose their buoyancy and the ability to regulate body temperature. (How Does the BP Oil Spill Impact Wildlife and Habitat?) Once birds are covered with oil, they have difficulty flying, or are completely unable to fly, making feeding and getting away from predators impossible. When whales, dolphins and porpoises surface to breathe, oily water can cover their blowholes and enter their lungs, making breathing difficult. (Gulf Oil Spill: Effects on Wildlife and Habitats)

Figure 5 Oil coated on bird's feathers
Source: (Frances, 2010)

Chemical toxicity:
This is characteristic of lighter chemical components which are more bio-available, ie absorbed into organs, tissues and cells, and can have sub-lethal or lethal toxic effects. (Environmental Effects of Oil Spills)
Some of the most toxic components of oil include benzene, toluene, ethylbenzene, xylene, and polycyclic aromatic hydrocarbons. Dispersant also poses threat due to their complex mixture.
The use of dispersants is also likely increased the bioavailability of the oil (its ability to be taken up or acted upon by organisms) and increased the potential exposure of sensitive organisms. It also increases the exposure of organisms below the surface in the water column and at the seafloor to oil, dispersants, and oil-dispersant mixture (The Deepwater Horizon Oil Spill) because the smaller droplets eventually become heavier than water and sink into the water column, or the vertical expanse of water extending from the sea surface to bottom sediments. (Graham P. , 2010)

Ecological changes:
There might be a loss of key organisms with a specific function in an ecological community. (Environmental Effects of Oil Spills)
Oil will likely reduce the amount and health of all prey species, reducing the food available for marine mammals, seabirds and sea turtles. For example, plankton is the foundation for nearly all life in the Gulf of Mexico (and the ocean), and they will most likely be affected. Contaminants from the spill and the dispersants are likely to concentrate in the upper food chain due to bioaccumulation. (Gulf Oil Spill: Effects on Wildlife and Habitats)
The oil’s toxicity may have hit egg and larval organisms immediately, diminishing or even wiping out those age classes. Without these generations, population dips and cascading food web effects may become evident in the years ahead. (How Does the BP Oil Spill Impact Wildlife and Habitat?)

Contamination/ destruction of habitat:
The Gulf of Mexico contains nearly half of the coastal wetlands in the United States. Marshes, estuaries and bayous provide critical nursery and feeding grounds for hundreds of marine species. A large percentage of marine species that live in the open ocean as adults spend one critical life stage in coastal wetlands. Earlier oil spill studies in a comparable ecosystem showed extensive mortality in mangroves, sea grasses, coral reefs and algae from the spill. (Gulf Oil Spill: Effects on Wildlife and Habitats)

Figure 6 Oil spill responders trying to recover oil from a marsh oiled during the Mendicant Island, LA incident
Source: (Nomack, 2010)

Besides the ecological impacts, oil pollution also affects the economy (e.g. fisheries, industries depend on clean water, tourism, clean up cost), real estate (e.g. decline in property value) and loss of natural resources (large amount of crude oil to be considered useless). People's health could be also adversely affected by oils either when inhaling or touching oil products, or when eating contaminated sea food. (Effect of marine oil pollution on economy and human health)





Works Cited

Deepwater Horizon accident and response. (n.d.). Retrieved September 28, 2014, from BP: http://www.bp.com/en/global/corporate/gulf-of-mexico-restoration/deepwater-horizon-accident-and-response.html
Effect of marine oil pollution on economy and human health. (n.d.). Retrieved September 28, 2014, from Global Marine Oil Pollution Information Gateway: http://oils.gpa.unep.org/facts/economy-health.htm
Environmental Effects of Oil Spills. (n.d.). Retrieved September 28, 2014, from International Tanker Owners Pollution Federation Limited (ITOPF): http://www.itopf.com/knowledge-resources/documents-guides/environmental-effects/
Frances. (2010, June 2). Toxic Gulf Oil Spill Cleanup – Bird Washing Machine. Retrieved October 3, 2014, from the alternative consumer: http://www.alternativeconsumer.com/2010/06/02/toxic-gulf-oil-spill-cleanup-bird-washing-machine/
Graham, B., Reilly, W. K., Beinecke, F., Boesch, D. F., Garcia, T. D., Murray, C. A., et al. (2011). Deep Water The Gulf Oil Disaster and the Future of Offshore Drilling. United States: Oil Spill Commission.
Graham, P. (2010, August). Deep Sea Oil Spill Cleanup Techniques:Applicability, Trade-offs and Advantages. Retrieved September 28, 2014, from ProQuest: http://www.csa.com/discoveryguides/oil/review.pdf
Gulf Oil Spill: Effects on Wildlife and Habitats. (n.d.). Retrieved September 28, 2014, from New England Aquarium: http://www.neaq.org/conservation_and_research/oil_spill/effects_on_wildlife_and_habitats.php
Help NOAA Research Chemical Dispersants and Oil Spills. (2014, October 2). Retrieved October 3, 2014, from Office of Response and Restoration, National Oceanic and Atmospheric Administration: http://response.restoration.noaa.gov/about/media/help-noaa-research-chemical-dispersants-and-oil-spills.html
How Does the BP Oil Spill Impact Wildlife and Habitat? (n.d.). Retrieved September 28, 2014, from NATIONAL WILDLIFE FEDERATION: https://www.nwf.org/What-We-Do/Protect-Habitat/Gulf-Restoration/Oil-Spill/Effects-on-Wildlife.aspx
MICHEL, J., SCHOLZ, D., WARREN JR., S. R., & WALKER, A. H. (2005, April). IN-SITU BURNING A DECISION-MAKER’S GUIDE TO IN-SITU BURNING. Retrieved September 28, 2014, from American Petroleum Institute: http://www.api.org/environment-health-and-safety/clean-water/oil-spill-prevention-and-response/~/media/4BDBD6AABD534BF1B88EB203C6D8B8F4.ashx
National Oceanic and Atmospheric Administration. (2010, May 18). NOAA’s Oil Spill Response Using Boom in Response to Oil Spills. Retrieved September 28, 2014, from National Oceanic and Atmospheric Administration: http://www.noaa.gov/factsheets/new%20version/boom.pdf
Nomack, M. (2010, September 25). Environmental impacts of oil spills. Retrieved October 3, 2014, from The Encyclopedia OF EARTH: http://www.eoearth.org/view/article/158443/
Office of Response and Restoration. (2014, September 26). Spill Containment Methods. Retrieved September 28, 2014, from National Oceanic and Atmospheric Administration Office of Response and Restoration: http://response.restoration.noaa.gov/oil-and-chemical-spills/oil-spills/spill-containment-methods.html
Offshore. (n.d.). Retrieved September 28, 2014, from BP: http://www.bp.com/en/global/corporate/gulf-of-mexico-restoration/deepwater-horizon-accident-and-response/completing-the-response/offshore.html
Philips, R. H. (2010, June 5). More skimmer boats deployed to fight oil spill; many more on standby. Retrieved October 3, 2014, from Alabama Media Group: http://blog.al.com/live/2010/06/more_skimmer_boats_deployed_to.html
Ramseur, J. L., & Hagerty, C. L. (2014). Deepwater Horizon Oil Spill: Recent Activities and Ongoing Developments. United States: Congressional Research Service.
Summit Contracting. (2011, June 22). U.S. Coast Guard Cites Importance of In-Situ Burning During Deepwater Horizon Clean up. Retrieved October 3, 2014, from WordPress: http://summitcontracting.wordpress.com/tag/in-situ-burns/
The Deepwater Horizon Oil Spill. (n.d.). Retrieved September 28, 2014, from Society of Toxicology: https://www.toxicology.org/pm/Deepwater_oil_spill.pdf
THOMPSON, P. (2013, October 4). BP could be saved hundreds of millions of pounds over Gulf of Mexico oil spill after U.S. court stops bogus or inflated payments. Retrieved September 28, 2014, from Daily Mail: http://www.dailymail.co.uk/news/article-2442576/BP-wins-Gulf-Mexico-oil-spill-compensation-court-battle.html
Venosa, A. D. (n.d.). NRT FACT SHEET: BIOREMEDIATION IN OIL SPILL RESPONSE. Retrieved September 28, 2014, from US Environmental Protection Agency: http://www.epa.gov/oem/docs/oil/edu/biofact.pdf


No comments:

Post a Comment