Oil Contamination
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An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of
crude oil Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
from
tankers Tanker may refer to: Transportation * Tanker, a tank crewman (US) * Tanker (ship), a ship designed to carry bulk liquids ** Chemical tanker, a type of tanker designed to transport chemicals in bulk ** Oil tanker, also known as a petroleum tanke ...
, offshore platforms, drilling rigs and
wells Wells most commonly refers to: * Wells, Somerset, a cathedral city in Somerset, England * Well, an excavation or structure created in the ground * Wells (name) Wells may also refer to: Places Canada *Wells, British Columbia England * Wells ...
, as well as spills of refined petroleum products (such as gasoline,
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...
) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil. Oil spills penetrate into the structure of the
plumage Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Spills may take weeks, months or even years to clean up. Oil spills can have disastrous consequences for society; economically, environmentally, and socially. As a result, oil spill accidents have initiated intense media attention and political uproar, bringing many together in a political struggle concerning government response to oil spills and what actions can best prevent them from happening.


Largest oil spills

Crude oil and refined fuel spills from tanker ship accidents have damaged vulnerable ecosystems in Alaska, the Gulf of Mexico, the Galapagos Islands, France, the Sundarbans,
Ogoniland The Ogonis are a people in the Rivers South East senatorial district of Rivers State, in the Niger Delta region of southern Nigeria. They number just over 2 million and live in a homeland which they also refer to as Ogoniland. They share common ...
, and many other places. The quantity of oil spilled during accidents has ranged from a few hundred tons to several hundred thousand tons (e.g., ''Deepwater Horizon'' Oil Spill, ''
Atlantic Empress SS ''Atlantic Empress'' was a Greek oil tanker that in 1979 collided with the oil tanker '' Aegean Captain'' in the Caribbean, and eventually sank, having created the fifth largest oil spill on record and the largest ship-based spill having sp ...
'', '' Amoco Cadiz''), but volume is a limited measure of damage or impact. Smaller spills have already proven to have a great impact on ecosystems, such as the ''Exxon Valdez'' oil spill because of the remoteness of the site or the difficulty of an emergency environmental response. Oil spills in the Niger Delta are among the worst on the planet. Between 1970 and 2000, there were over 7,000 spills. Between 1956 and 2006, up to 1.5 million tons of oil were spilled in the Niger Delta. Oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin oil slick which can cover beaches with a thin coating of oil. These can kill seabirds, mammals, shellfish and other organisms they coat. Oil spills on land are more readily containable if a makeshift earth dam can be rapidly
bulldozed A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous tracks, ...
around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.


Human impact

An oil spill represents an immediate negative effects on human health, including respiratory and reproductive problems as well as liver, and immune system damage. Oil spills causing future oil supply to decline also effects the everyday life of humans such as the potential closure of beaches, parks, fisheries and fire hazards. The Kuwaiti oil fires produced air pollution that caused respiratory distress. The ''Deepwater Horizon'' explosion killed eleven oil rig workers. The fire resulting from the Lac-Mégantic derailment killed 47 and destroyed half of the town's centre. Spilled oil can also contaminate drinking water supplies. For example, in 2013 two different oil spills contaminated water supplies for 300,000 in Miri, Malaysia; 80,000 people in
Coca, Ecuador Puerto Francisco de Orellana (), also known as El Coca (), is the capital of province of Orellana in eastern Ecuador. The city is located in the Amazon Rainforest at the confluence of the Coca River and the Napo River (the smaller Payamino River ...
. In 2000, springs were contaminated by an oil spill in Clark County, Kentucky. Contamination can have an economic impact on tourism and marine resource extraction industries. For example, the ''Deepwater Horizon'' oil spill impacted beach tourism and fishing along the Gulf Coast, and the responsible parties were required to compensate economic victims.


Environmental effects

The threat posed to birds, fish, shellfish and crustaceans from spilled oil was known in England in the 1920s, largely through observations made in Yorkshire. The subject was also explored in a scientific paper produced by the
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
in the US in 1974 which considered impacts to fish, crustaceans and molluscs. The paper was limited to 100 copies and was described as a draft document, not to be cited. In general, spilled oil can affect animals and plants in two ways: dirесt from the oil and from the response or cleanup process. There is no clear relationship between the amount of oil in the aquatic environment and the likely impact on biodiversity. A smaller spill at the wrong time/wrong season and in a sensitive environment may prove much more harmful than a larger spill at another time of the year in another or even the same environment. Oil penetrates into the structure of the plumage of birds and the fur of mammals, reducing their insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Animals who rely on scent to find their babies or mothers cannot do so due to the strong scent of the oil. This causes a baby to be rejected and abandoned, leaving the babies to starve and eventually die. Oil can impair a bird's ability to fly, preventing it from foraging or escaping from predators. As they
preen Preen may refer to: Birds *Preening, personal grooming of a bird's feathers especially by using its beak *Preen gland, also called the uropygial gland, an oil gland found in many bird species *Preen oil, an oil made by the uropygial gland found ...
, birds may ingest the oil coating their feathers, irritating the digestive tract, altering liver function, and causing kidney damage. Together with their diminished foraging capacity, this can rapidly result in dehydration and
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
imbalance. Some birds exposed to petroleum also experience changes in their hormonal balance, including changes in their luteinizing protein. The majority of birds affected by oil spills die from complications without human intervention. Some studies have suggested that less than one percent of oil-soaked birds survive, even after cleaning, although the survival rate can also exceed ninety percent, as in the case of the ''MV Treasure'' oil spill. Oil spills and oil dumping events have been impacting sea birds since at least the 1920s and was understood to be a global problem in the 1930s. Heavily furred exposed to oil spills are affected in similar ways. Oil coats the fur of sea otters and
seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...
, reducing its insulating effect, and leading to fluctuations in body temperature and hypothermia. Oil can also blind an animal, leaving it defenseless. The ingestion of oil causes dehydration and impairs the digestive process. Animals can be poisoned, and may die from oil entering the lungs or liver. In addition, oil spills can also harm air quality. The chemicals in crude oil are mostly hydrocarbons that contains toxic chemicals such as benzenes, toluene, poly-aromatic hydrocarbon and oxygenated polycyclic aromatic hydrocarbons. These chemicals can introduce adverse health effects when being inhaled into human body. In addition, these chemicals can be oxidized by oxidants in the atmosphere to form fine particulate matter after they evaporate into the atmosphere. These particulates can penetrate lungs and carry toxic chemicals into the human body. Burning surface oil can also be a source for pollution such as soot particles. During the cleanup and recovery process, it will also generate air pollutants such as nitric oxides and ozone from ships. Lastly, bubble bursting can also be a generation pathway for particulate matter during an oil spill. During the Deepwater Horizon oil spill, significant air quality issues were found on the Gulf Coast, which is the downwind of DWH oil spill. Air quality monitoring data showed that criteria pollutants had exceeded the health-based standard in the coastal regions.


Sources and rate of occurrence

Oil spills can be caused by human error, natural disasters, technical failures or deliberate releases. It is estimated that 30-50% of all oil spills are directly or indirectly caused by human error, with approximately 20-40% of oil spills being attributed to equipment failure or malfunction. Causes of oil spills are further distinguished between deliberate releases, such as operational discharges or acts of war and accidental releases. Accidental oil spills are in the focus of the literature, although some of the largest oil spills ever recorded, the Gulf War Oil Spill (sea based) and Kuwaiti Oil Fires (land based) were deliberate acts of war. The academic study of sources and causes of oil spills identifies vulnerable points in oil transportation infrastructure and calculates the likelihood of oil spills happening. This can then guide prevention efforts and regulation policies


Natural seeps

Around 40-50% of all oil released into the oceans stems from natural seeps from seafloor rocks. This corresponds to approximately 600,000 tons annually on a global level. While natural seeps are the single largest source of oil spills, they are considered less problematic because ecosystems have adapted to such regular releases. For instance, on sites of natural oil seeps, ocean bacteria have evolved to digest oil molecules.


Oil tankers and vessels

Vessels can be the source of oil spills either through operational releases of oil or in the case of oil tanker accidents. Operational discharges from vessels are estimated to account for 21% of oil releases from vessels. They occur as a consequence of failure to comply with regulations or arbitrary discharges of waste oil and water containing such oil residues. Such operational discharges are regulated through the MARPOL convention. Operational releases are frequent, but small in the amount of oil spilled per release, and are often not in the focus of attention regarding oil spills. There has been a steady decrease of operational discharges of oil, with an additional decrease of around 50% since the 1990s. Accidental oil tank vessel spills account for approximately 8-13% of all oil spilled into the oceans. The main causes of oil tank vessel spills are collision (29%), grounding (22%), mishandling (14%) and sinking (12%), among others. Oil tanker spills are considered a major ecological threat due to the large amount of oil spilled per accident and the fact that major sea traffic routes are close to Large Marine Ecosystems. Around 90% of the world's oil transportation is through oil tankers, and the absolute amount of seaborne oil trade is steadily increasing. However, there has been a reduction of the number of spills from oil tankers and of the amount of oil released per oil tanker spill. In 1992, MARPOL was amended and made it mandatory for large tankers (5,000 dwt and more) to be fitted with
double hull A double hull is a ship hull design and construction method where the bottom and sides of the ship have two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is some dis ...
s. This is considered to be a major reason for the reduction of oil tanker spills, alongside other innovations such as
GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
, sectioning of vessels and sea lanes in narrow straits.


Offshore oil platforms

Accidental spills from
oil platform An oil platform (or oil rig, offshore platform, oil production platform, and similar terms) is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platfor ...
s nowadays account for approximately 3% of oil spills in the oceans. Prominent offshore oil platform spills typically occurred as a result of a
blowout Blowout or Blow out may refer to: Film and television *''Blow Out'', a 1981 film by Brian De Palma * ''The Blow Out'', a 1936 short film * ''Blow Out'' (TV series), a TV series on Bravo * "Blow Out" (''Prison Break''), an episode of ''Prison ...
. They can go on for months until relief wells have been drilled, resulting in enormous amounts of oil leaked. Notable examples of such oil spills are Deepwater Horizon and
Ixtoc I Ixtoc 1 was an exploratory oil well being drilled by the semi-submersible drilling rig ''Sedco 135'' in the Bay of Campeche of the Gulf of Mexico, about northwest of Ciudad del Carmen, Campeche in waters deep. On 3 June 1979, the well suffer ...
. While technologies for drilling in deep water have significantly improved in the past 30–40 years, oil companies move to drilling sites in more and more difficult places. This ambiguous development results in no clear trend regarding the frequency of offshore oil platform spills.


Pipelines

Pipelines as sources of oil spills are estimated to contribute 1% of oil pollution to the oceans. Reasons for this are underreporting, and many oil pipeline leaks occur on land with only fractions of that oil reaching the oceans. Overall, however, there has been a substantial increase of pipeline oil spills in the past four decades. Prominent examples include oil spills of pipelines in the Niger Delta. Pipeline oil spills can be caused by trawling of fishing boats, natural disasters, pipe corrosion, construction defects and deliberate sabotage or attacks, as with the Caño Limón-Coveñas pipeline in Colombia.


Other sources

Recreational boats can spill oil into the ocean because of operational or human error and unpreparedness. The amounts are however small, and such oil spills are hard to track due to underreporting. Oil can reach the oceans as oil and fuel from land-based sources. It is estimated that runoff oil and oil from rivers are responsible for 11% of oil pollution to the oceans. Such pollution can also be oil on roads from land vehicles, which is then flushed into the oceans during rainstorms. Purely land-based oil spills are different from maritime oil spills in that oil on land does not spread as quickly as in water, and effects thus remain local.


Cleanup and recovery

Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Physical cleanups of oil spills are also very expensive. Until the 1960s, the best method for remediation consisted of putting
straw Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number ...
on the spill and retrieving the oil-soaked straw manually. Chemical remediation is the norm as of the early 21st Century, using compounds that can herd and thicken oil for physical recover, disperse oil in the water, or facilitate burning the oil off. The future of oil cleanup technology is likely the use of microorganisms such as Fusobacteriota (formerly Fusobacteria), species demonstrate potential for future oil spill cleanup because of their ability to colonize and degrade oil slicks on the sea surface. There are three kinds of oil-consuming bacteria. Sulfate-reducing bacteria (SRB) and acid-producing bacteria are anaerobic, while general aerobic bacteria (GAB) are aerobic. These bacteria occur naturally and will act to remove oil from an ecosystem, and their biomass will tend to replace other populations in the food chain. The chemicals from the oil which dissolve in water, and hence are available to bacteria, are those in the
water associated fraction The water associated fraction (WAF), sometimes termed the water-soluble fraction (W.S.F.), is the solution of low molecular mass hydrocarbons naturally released from petroleum hydrocarbon mixtures in contact with water. Although generally regarded ...
of the oil. Methods for cleaning up include: * Bioremediation: use of microorganisms or
biological agents A biological agent (also called bio-agent, biological threat agent, biological warfare agent, biological weapon, or bioweapon) is a bacterium, virus, protozoan, parasite, fungus, or toxin that can be used purposefully as a weapon in bioterrorism ...
to break down or remove oil; such as ''
Alcanivorax ''Alcanivorax'' is a genus of alkane-degrading marine bacteria Marine prokaryotes are marine bacteria and marine archaea. They are defined by their habitat as prokaryotes that live in marine environments, that is, in the saltwater of seas ...
'' bacteria or ''
Methylocella silvestris ''Methylocella silvestris'' is a bacterium from the genus ''Methylocella spp'' which are found in many acidic soils and wetlands. Historically, ''Methylocella silvestris'' was originally isolated from acidic forest soils in Germany, and it is de ...
''. * Bioremediation Accelerator: a binder molecule that moves hydrocarbons out of water and into gels, when combined with nutrients, encourages natural bioremediation. Oleophilic, hydrophobic chemical, containing no bacteria, which chemically and physically bonds to both soluble and insoluble hydrocarbons. The accelerator acts as a herding agent in water and on the surface, floating molecules such as phenol and
BTEX In the petroleum refining and petrochemical industries, the initialism BTX refers to mixtures of benzene, toluene, and the three xylene isomers, all of which are aromatic hydrocarbons. The xylene isomers are distinguished by the designations ''or ...
to the surface of the water, forming gel-like agglomerations. Undetectable levels of hydrocarbons can be obtained in produced water and manageable water columns. By overspraying sheen with bioremediation accelerator, sheen is eliminated within minutes. Whether applied on land or on water, the nutrient-rich emulsion creates a bloom of local, indigenous, pre-existing, hydrocarbon-consuming bacteria. Those specific bacteria break down the hydrocarbons into water and carbon dioxide, with EPA tests showing 98% of alkanes biodegraded in 28 days; and aromatics being biodegraded 200 times faster than in nature they also sometimes use the hydrofireboom to clean the oil up by taking it away from most of the oil and burning it. * Controlled
burning Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...
can effectively reduce the amount of oil in water, if done properly. But it can only be done in low wind, and can cause air pollution. * Dispersants can be used to dissipate oil slicks. A dispersant is either a non-surface active polymer or a
surface-active substance Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...
added to a suspension, usually a
colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...
, to improve the separation of particles and to prevent settling or clumping. They may rapidly disperse large amounts of certain oil types from the
sea surface The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...
by transferring it into the water column. They will cause the oil slick to break up and form water-soluble micelles that are rapidly diluted. The oil is then effectively spread throughout a larger volume of water than the surface from where the oil was dispersed. They can also delay the formation of persistent
oil-in-water emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...
s. However, laboratory experiments showed that dispersants increased toxic hydrocarbon levels in fish by a factor of up to 100 and may kill fish eggs. Dispersed oil droplets infiltrate into deeper water and can lethally contaminate coral. Research indicates that some dispersants are toxic to corals. A 2012 study found that
Corexit Corexit (often styled COREXIT) is a product line of oil dispersants used during oil spill response operations. It is produced by Nalco Holding Company, an indirect subsidiary of Ecolab. Corexit was originally developed by the Standard Oil Compa ...
dispersant had increased the toxicity of oil by up to 52 times. In 2019, the U.S. National Academies released a report analyzing the advantages and disadvantages of several response methods and tools. * Watch and wait: in some cases, natural attenuation of oil may be most appropriate, due to the invasive nature of facilitated methods of remediation, particularly in ecologically sensitive areas such as wetlands. *
Dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing da ...
: for oils dispersed with detergents and other oils denser than water. * Skimming: Requires calm waters at all times during the process. Vessels used for skimming clean up are called Gulp Oil Skimmers. * Solidifying: Solidifiers are composed of tiny, floating, dry ice pellets, and hydrophobic polymers that both
adsorb Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a fl ...
and absorb. They clean up oil spills by changing the physical state of spilled oil from liquid to a solid, semi-solid or a rubber-like material that floats on water. Solidifiers are insoluble in water, therefore the removal of the solidified oil is easy and the oil will not leach out. Solidifiers have been proven to be relatively non-toxic to aquatic and wildlife and have been proven to suppress harmful vapors commonly associated with hydrocarbons such as benzene, xylene and naphtha. The reaction time for solidification of oil is controlled by the surface area or size of the polymer or dry pellets as well as the viscosity and thickness of the oil layer. Some solidifier product manufacturers claim the solidified oil can be thawed and used if frozen with dry ice or disposed of in landfills, recycled as an additive in asphalt or rubber products, or burned as a low ash fuel. A solidifier called C.I.Agent (manufactured by
C.I.Agent Solutions C.I.Agent Solutions is a Louisville, Kentucky-based company that specializes in environmental protection services. The company develops products to clean up hydrocarbon (fuel and oil) spills on land and water. Their main product is called C.I.Age ...
of Louisville, Kentucky) is being used by BP in granular form, as well as in Marine and Sheen Booms at
Dauphin Island Dauphin Island is an island town in Mobile County, Alabama, United States, on a barrier island of the same name, in the Gulf of Mexico. It incorporated in 1988. The population was 1,778 at the 2020 census, up from 1,238 at the 2010 census. The t ...
and
Fort Morgan, Alabama Fort Morgan, also known as Fort Bowyer, is an unincorporated community in Baldwin County, Alabama, United States. It is west of Gulf Shores on Mobile Point. Mobile Point extends from Gulf Shores to the west, towards historic Fort Morgan at th ...
, to aid in the Deepwater Horizon oil spill cleanup. * Vacuum and centrifuge: oil can be sucked up along with the water, and then a centrifuge can be used to separate the oil from the water – allowing a tanker to be filled with near pure oil. Usually, the water is returned to the sea, making the process more efficient, but allowing small amounts of oil to go back as well. This issue has hampered the use of centrifuges due to a United States regulation limiting the amount of oil in water returned to the sea. * Beach Raking: coagulated oil that is left on the beach can be picked up by machinery. Equipment used includes: * Booms: large floating barriers that round up oil and lift the oil off the water * Skimmers: skim the oil * Sorbents: large absorbents that absorb oil and adsorb small droplets * Chemical and biological agents: helps to break down the oil * Vacuums: remove oil from beaches and water surface * Shovels and other road equipment: typically used to clean up oil on beaches


Prevention

* Secondary containment – methods to prevent releases of oil or hydrocarbons into the environment. * Oil Spill Prevention Control and Countermeasures (SPCC) program by the United States Environmental Protection Agency. * Double-hulling – build
double hull A double hull is a ship hull design and construction method where the bottom and sides of the ship have two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is some dis ...
s into vessels, which reduces the risk and severity of a spill in case of a collision or grounding. Existing single-hull vessels can also be rebuilt to have a double hull. * Thick-hulled railroad transport tanks. Spill response procedures should include elements such as; * A listing of appropriate protective clothing, safety equipment, and cleanup materials required for spill cleanup (gloves, respirators, etc.) and an explanation of their proper use; * Appropriate evacuation zones and procedures; * Availability of fire suppression equipment; * Disposal containers for spill cleanup materials; and * The first aid procedures that might be required.


Environmental Sensitivity Index (ESI) mapping

Environmental Sensitivity Indexes (ESI) are tools used to create Environmental Sensitivity Maps (ESM). ESM's are pre-planning tools used to identify sensitive areas and resources prior to an oil spill event in order to set priorities for protection and plan clean-up strategies. It is to date the most commonly used mapping tool for sensitive area plotting. The ESI has three components: A shoreline type ranking system, a biological resources section, and a human-use resource category.NOAA (2002). Environmental Sensitivity Index Guidelines, version 3.0. NOAA Technical Memorandum NOS OR&R 11. Seattle: Hazardous Response and Assessment Division, National Oceanic and Atmospheric Administration, 129p.


History and development

ESI is the most frequently used sensitivity mapping tool yet. It was first applied in 1979 in response to an oil-spill near Texas in the Gulf of Mexico. To this time, ESI maps were prepared merely days in advance of one's arrival to an oil spill location. ESMs used to be atlases, maps consisting of thousands of pages that could solely work with spills in the oceans. In the past 3 decades, this product has been transformed into a versatile online tool. This conversion allows sensitivity indexing to become more adaptable and in 1995 by the US National Oceanic and Atmospheric Administration (NOAA) worked on the tool allowing ESI to extended maps to lakes, rivers, and estuary shoreline types. ESI maps have since become integral to  collecting, synthesizing, and producing data which have previously never been accessible in digital formats. Especially in the United States, the tool has made impressive advancements in developing tidal bay protection strategies, collecting seasonal information and generally in the modelling of sensitive areas. Together with Geographic Information System Mapping (GIS), ESI integrates their techniques to successfully geographically reference the three different types of resources.


Usage and application

The ESI depicts environmental stability, coastal resilience to maritime related catastrophes, and the configurations of a stress-response relationship between all things maritime. Created for ecological-related decision making, ESMs can accurately identify sensitive areas and habitats, clean-up responses, response measures and monitoring strategies for oil-spills. The maps allow experts from varying fields to come together and work efficiently during fast-paced response operations. The process of making an ESI atlas involves GIS technology. The steps involve, first zoning the area that is to be mapped, and secondly, a meeting with local and regional experts on the area and its resources.IPIECA, IMO, OGP. (2012). ''Sensitivity mapping for oil spill response'' (OGP Report Number 477). Following, all the shoreline types, biological, and human use resources need to be identified and their locations pinpointed. Once all this information is gathered, it then becomes digitized. In its digital format, classifications are set in place, tables are produced and local experts refine the product before it gets released. ESI's current most common use is within contingency planning. After the maps are calculated and produced, the most sensitive areas get picked out and authenticated. These areas then go through a scrutinization process throughout which methods of protection and resource assessments are obtained. This in-depth research is then put back into the ESMs to develop their accuracy and allowing for tactical information to be stored in them as well. The finished maps are then used for drills and trainings for clean-up efficiency. Trainings also often help to update the maps and tweak certain flaws that might have occurred in the previous steps.


ESI Categories


Shoreline type

Shoreline type is classified by rank depending on how easy the target site would be to clean up, how long the oil would persist, and how sensitive the shoreline is. The ranking system works on a 10-point scale where the higher the rank, the more sensitive a habitat or shore is. The coding system usually works in colour, where warm colours are used for the increasingly sensitive types and cooler colours are used for robust shores. For each navigable body of water, there is a feature classifying its sensitivity to oil. Shoreline type mapping codes a large range of ecological settings including
estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
, lacustrine, and
riverine A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...
environments. Floating oil slicks put the shoreline at particular risk when they eventually come ashore, covering the
substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...
with oil. The differing substrates between shoreline types vary in their response to oiling, and influence the type of cleanup that will be required to effectively decontaminate the shoreline. Hence ESI shoreline ranking helps committees identify which clean-up techniques are approved or detrimental the natural environment. The exposure the shoreline has to wave energy and tides, substrate type, and slope of the shoreline are also taken into account—in addition to biological productivity and sensitivity.NOAA (2008). Introduction to Environmental Sensitivity Index maps. NOAA Technical Manual. Seattle: Hazardous Response and Assessment Division, National Oceanic and Atmospheric Administration, 56p. Mangroves and marshes tend to have higher ESI rankings due to the potentially long-lasting and damaging effects of both oil contamination and cleanup actions. Impermeable and exposed surfaces with high wave action are ranked lower due to the reflecting waves keeping oil from coming onshore, and the speed at which natural processes will remove the oil.


Biological resources

Within the biological resources, the ESI maps protected areas as well as those with bio-diverse importance. These are usually identified through the UNEP-WCMC Integrated Biodiversity Assessment Tool. There are varying types of coastal habitats and ecosystems and thus also many endangered species that need to be considered when looking at affected areas post oil spills. The habitats of plants and animals that may be at risk from oil spills are referred to as "elements" and are divided by functional group. Further classification divides each element into species groups with similar life histories and behaviors relative to their vulnerability to oil spills. There are eight element groups: birds, reptiles, amphibians, fish, invertebrates, habitats and plants, wetlands, and marine mammals and terrestrial mammals. Element groups are further divided into sub-groups, for example, the ‘marine mammals’ element group is divided into dolphins, manatees, pinnipeds (seals, sea lions & walruses),
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
s,
sea otter The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the small ...
s and whales. Necessary when ranking and selecting species is their vulnerability to the oil spills themselves. This not only includes their reactions to such events but also their fragility, the scale of large clusters of animals, whether special life stages occur ashore, and whether any present species is threatened, endangered or rare.
IMO IMO or Imo may refer to: Biology and medicine * Irish Medical Organisation, the main organization for doctors in the Republic of Ireland * Intelligent Medical Objects, a privately held company specializing in medical vocabularies * Isomaltooligos ...
/ IPIECA (1994). Sensitivity Mapping for Oil Spill Response. International Maritime Organization/ International Petroleum Industry Environmental Conservation Association Report Series, Volume 1. 22p.
The way in which the biological resources are mapped is through symbols representing the species, and polygons and lines to map out the special extent of the species.IPIECA, IMO (1994). ''Sensitivity Mapping for Oil Spill Response'', (IMO/IPIECA report series). Volume 1, p.28 The symbols also have the ability to identify the most vulnerable of a species life stages, such as the
molting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
, nesting, hatching or migration patterns. This allows for more accurate response plans during those given periods. There is also a division for sub-tidal habitats which are equally important to coastal biodiversity including kelp, coral reefs and sea beds which are not commonly mapped within the shoreline ESI type.


Human-use resources

Human-use resources are also often referred to as socio-economic features, which map inanimate resources that have the potential to be directly impacted by oil pollution. Human-use resources that are mapped within the ESI will have socio-economic repercussions to an oil spill. These resources are divided into four major classifications:
archaeological Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
importance or cultural resource site, high-use recreational areas or shoreline access points, important protected management areas, and resource origins. Some examples include airports, diving sites, popular beach sites, marinas, hotels, factories, natural reserves or marine sanctuaries. When mapped, the human-use resources the need protecting must be certified by a local or regional policy maker. These resources are often extremely vulnerable to seasonal changes due to ex. fishing and tourism. For this category there are also a set of symbols available to demonstrate their importance on ESMs.


Estimating the volume of a spill

By observing the thickness of the film of oil and its appearance on the surface of the water, it is possible to estimate the quantity of oil spilled. If the surface area of the spill is also known, the total volume of the oil can be calculated. Oil spill model systems are used by industry and government to assist in planning and emergency decision making. Of critical importance for the skill of the oil spill model prediction is the adequate description of the wind and current fields. There is a worldwide oil spill modelling (WOSM) program. Tracking the scope of an oil spill may also involve verifying that hydrocarbons collected during an ongoing spill are derived from the active spill or some other source. This can involve sophisticated analytical chemistry focused on finger printing an oil source based on the complex mixture of substances present. Largely, these will be various hydrocarbons, among the most useful being
polyaromatic hydrocarbons A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. P ...
. In addition, both oxygen and nitrogen heterocyclic hydrocarbons, such as parent and alkyl homologues of carbazole, quinoline, and pyridine, are present in many crude oils. As a result, these compounds have great potential to supplement the existing suite of hydrocarbons targets to fine-tune source tracking of petroleum spills. Such analysis can also be used to follow weathering and degradation of crude spills.


See also

*
Automated Data Inquiry for Oil Spills The Automated Data Inquiry for Oil Spills (ADIOS2) software is an oil weathering model provided by NOAA that incorporates a database containing more than a thousand crude oils and refined products, and provides quick estimates of the expected chara ...
* Environmental issues with petroleum * Environmental issues with shipping *
LNG spill A liquefied natural gas (LNG) spill can happen during an accident or an intentional act. LNG is normally stored and transported in liquid form at a temperature of approximately . If this cooled liquid is released from a storage facility, pipeline, o ...
* Storm oil *
Low-temperature thermal desorption For environmental remediation, Low-temperature thermal desorption (LTTD), also known as low-temperature thermal volatilization, thermal stripping, and soil roasting, is an ex-situ remedial technology that uses heat to physically separate petroleu ...
*
National Oil and Hazardous Substances Pollution Contingency Plan The National Oil and Hazardous Substances Pollution Contingency Plan or National Contingency Plan (NCP) is the United States federal government's blueprint for responding to oil spills and hazardous substance releases. It documents national response ...
*
Ohmsett Ohmsett is the National Oil Spill Response & Renewable Energy Test Facility, located in Leonardo, New Jersey. The name Ohmsett is an acronym for "Oil and Hazardous Materials Simulated Environmental Test Tank". Facility This is the only facili ...
(Oil and Hazardous Materials Simulated Environmental Test Tank) * Oil Pollution Act of 1990 (in the US) *
Oil well An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may ...
*
Penguin sweater Penguin sweaters, also known as penguin jumpers, are sweaters knitted for penguins that have been caught in oil slicks. When an oil spill affects penguins they have in the past been sometimes dressed in knitted sweaters, supposedly to stop them fr ...
*
Project Deep Spill Project Deep Spill was the first intentional deepwater oil spill, in order to study how crude oil behaved in-depth. A Joint Industry Project comprising 23 oil companies and the Minerals Management Service performed a sea trial in late June 2000 i ...
, the first intentional deepwater oil and gas spill * '' Pseudomonas putida'' (used for degrading oil) *
S-200 (fertilizer) S-200 is a bioremediation product used to clean up oil spills. It is an oleophilic nitrogen-phosphorus nutrient that promotes the growth of micro-organisms that degrade hydrocarbons (such as oil and fuel). S-200 bonds to the hydrocarbon to elimi ...
*
ShoreZone ShoreZone is a mapping program that uses oblique aerial images acquired at low altitude, and during the lowest daylight tides of the year, to inventory alongshore and across-shore geomorphological and biological features of the Pacific Northwest ...
*
Spill containment Spill containment is where spills of chemicals, oils, sewage etc. are contained within a barrier or drainage system rather than being absorbed at the surface. One method is to use an inflatable stopper or pneumatic bladder which is inserted into t ...
*
Tarball Tarball may refer to: * Tarball (computing), a type of archive file * Tarball (oil), a blob of semi-solid oil found on or near the ocean {{Disambiguation ...


References


Further reading

*Nelson-Smith, ''Oil Pollution and Marine Ecology'', Elek Scientific, London, 1972; Plenum, New York, 1973 *''Oil Spill Case Histories 1967–1991'', NOAA/Hazardous Materials and Response Division, Seattle, WA, 1992 *Ramseur, Jonathan L
''Oil Spills: Background and Governance''
Congressional Research Service, Washington, DC, September 15, 2017 {{authority control Technology hazards Bird mortality Ocean pollution Product safety scandals Road hazards Disasters in Nigeria