document_title: Amniotic fluid index

question_text: what is the normal range of afi in pregnancy

root

text: Amniotic fluid index

text: Amniotic fluid index (AFI) is a quantitative estimate of amniotic fluid[1] and an indicator of fetal well-being. It is a part of the biophysical profile.[1]

tag: p

text:
AFI is the score (expressed in cm) given to the amount of amniotic fluid seen on ultrasonography of a pregnant uterus. To determine the AFI, doctors may use a four-quadrant technique,[2] when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others,[3] or the so-called "Single Deepest Pocket" technique.[4]
An AFI between 8-18 is considered normal.[5] Median AFI level is approximately 14 from week 20 to week 35,[6] when the amniotic fluid begins to reduce in preparation for birth.
An AFI < 5-6 is considered as oligohydramnios.[3] The exact number can vary by gestational age. The fifth percentile for gestational age is sometimes used as a cutoff value.[7]
An AFI > 20-24 is considered as polyhydramnios.[3][8]

tag: ul

text: Causes of low amniotic fluid[edit]

text: Leaking or rupture of membranes

text: Leaking or rupture of membranes may be caused by a gush of fluid or a slow constant trickle of fluid. This is due to a tear in the membrane. Premature rupture of membranes can also result in low amniotic fluid levels.

text: Placental problems

text: Placental problems may cause low amniotic fluid. If the placenta is not providing enough blood and nutrients to the baby, then the baby may stop recycling fluid.

text: Birth defects

text: Birth defects may occur if the fetus has problems with the development of the kidneys or urinary tract, which could cause little urine production, and it can lead to low levels of amniotic fluid.

text: Maternal complications

text: Maternal complications may cause low amniotic fluid. Some factors such as hypertension, diabetes, dehydration, preeclampsia, and chronic hypoxia in a woman can have an effect on amniotic fluid levels.


document_title: Siliceous ooze

question_text: where in the oceans are siliceous oozes typically found

text: Siliceous ooze

text: Siliceous ooze is a siliceous pelagic sediment that covers large areas of the deep ocean floor. Siliceous oozes consist predominantly of the remains of microscopic sea creatures, mostly those of diatoms and radiolarians. Sometimes siliceous oozes also contain silicoflagellates and the spicules of sponges.

text:
Diatoms are golden-brown algae that construct an opaline silica microscopic shell that is known as a "frustule".
Silicoflagellates are a minor group of marine algae that construct microscopic shells composed of opaline silica.
Radiolarians are marine protists that also construct microscopic shells composed of opaline silica and are distant relatives of the foraminifera.[1]

text: Siliceous ooze accumulates on the ocean floor where the bottom waters are close to saturation with respect to silica, and the opaline remains of either diatoms, radiolarians, silicoflagellates, and sponge spicules, or combinations of these are rapidly buried. These conditions exist within areas of high biological productivity associated with volcanic islands and nutrient-rich upwelling zones. As the least common type of pelagic sediment, it covers only 15% of the ocean floor. It accumulates at a slower rate than calcareous ooze: 0.2–1 cm / 1000 yr.[1]

text: After burial, most siliceous oozes remain unconsolidated. However, a fraction of siliceous oozes dissolve and reprecipitate as a result of diagenesis to form chert beds or nodules. When siliceous oozes are incorporated into orogenic belts associated with subduction zones, they are also altered by diagenesis, and lithified to form chert, i.e. radiolarian chert.[1]


document_title: Forbidden fruit

question_text: who ate the apple from the forbidden tree first

text: Forbidden fruit

text: Biblical narrative[edit]

text: The narrative of the Book of Genesis places the first man and woman (Adam and Eve) in a garden where they may eat the fruit of many trees but are forbidden by God to eat from the "tree of knowledge of good and evil".

text: And Jehovah God commanded the man, saying, Of every tree of the garden thou mayest freely eat: but of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.

text: In Genesis 3, a serpent tempts the woman:

text: And the serpent said unto the woman, Ye shall not surely die: for God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as God, knowing good and evil.

text: Desiring this wisdom, the woman eats the forbidden fruit and gives some to the man who also eats it. They become aware of their "nakedness" and make fig-leaf clothes, and hide themselves when God approaches. God curses the man and woman (and the serpent), and expels them from the garden and thereby from eternal life.

text: Identifications and depictions[edit]

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2016) (Learn how and when to remove this template message)

tag: table

text: The word fruit appears in Hebrew as פֶּ֫רִי (pərî ). As to which fruit may have been the fabled forbidden fruit of the Garden of Eden, possibilities include grape, pomegranate,[3] fig,[4] carob,[3] etrog or citron,[3] pear, mushrooms, and quince. The pseudepigraphic Book of Enoch describes the tree of knowledge: "It was like a species of the Tamarind tree, bearing fruit which resembled grapes extremely fine; and its fragrance extended to a considerable distance. I exclaimed, How beautiful is this tree, and how delightful is its appearance!" (1 Enoch 31:4).

text: An alternative view is that the forbidden fruit is metaphorical, possibly the fruit of the womb, i.e. sex and procreation from the tree of life. In his Autobiography of a Yogi, Hindu spiritual teacher Paramhansa Yogananda cites an interpretation by his master Swami Sri Yuktiswar that the Garden of Eden refers to man's body, with the fruit in the center being that of the sexual organs.[5]

text: Quince[edit]

text: Apple[edit]

text: In Western Europe, the fruit was often depicted as an apple. This was possibly because of a misunderstanding of – or a pun on – mălum, a native Latin noun which means evil (from the adjective malus), and mālum, another Latin noun, borrowed from Greek μῆλον, which means apple. In the Vulgate, Genesis 2:17 describes the tree as de ligno autem scientiae boni et mali : "but of the tree [literally wood ] of knowledge of good and evil" (mali here is the genitive of malum).

text: The larynx, specifically the laryngeal prominence that joins the thyroid cartilage, in the human throat is noticeably more prominent in males and was consequently called an Adam's apple, from a notion that it was caused by the forbidden fruit getting stuck in Adam's throat as he swallowed it.[6]

text: Grape[edit]

text: Rabbi Meir says that the fruit was a grape, made into wine.[7] The Zohar explains similarly that Noah attempted (but failed) to rectify the sin of Adam by using grape wine for holy purposes.[8][9] The midrash of Bereishit Rabah states that the fruit was grape,[10] or squeezed grapes (perhaps alluding to wine).[11]

text: Fig[edit]

text: The Bible states in the book of Genesis that Adam and Eve had made their own fig leaf clothing: "And the eyes of them both were opened, and they knew that they were naked; and they sewed fig-leaves together, and made themselves girdles".[12] Based on that reference, the forbidden fruit may have been the fig.

text: Rabbi Nechemia, based on the Talmud, supports the idea that the fruit was a fig, as it was from fig leaves that God made garments for Adam and Eve upon expelling them from the Garden. "By that with which they were made low were they rectified."[13]

text: Since the fig is a long-standing symbol of female sexuality, it enjoyed a run as a favorite understudy to the apple as the forbidden fruit during the Italian Renaissance. The most famous depiction of the fig as the forbidden fruit was painted by Michelangelo Buonarroti in his masterpiece fresco on the Sistine Chapel ceiling.[14]

text: Pomegranate[edit]

text: Proponents of the theory that the Garden of Eden was located somewhere in what is now known as the Middle East suggest that the fruit was actually a pomegranate, a plant indigenous from Iraq to the Himalayas and cultivated since ancient times.[15] The association of the pomegranate with knowledge of the underworld as provided in the Ancient Greek legend of Persephone may also have given rise to an association with knowledge of the otherworld, tying-in with knowledge that is forbidden to mortals.

text: Wheat[edit]

text: Rabbi Yehuda proposes that the fruit was wheat, because "a baby does not know to call its mother and father until it tastes the taste of grain."[7]

text: In Hebrew, wheat is "khitah", which has been considered to be a pun on "khet", meaning "sin".[3]

text: Although commonly confused with a seed, in the study of botany a wheat berry is technically a simple fruit known as a caryopsis, which has the same structure as an apple. Just as an apple is a fleshy fruit that contains seeds, a grain is a dry fruit that absorbs water and contains a seed. The confusion comes from the fact that the fruit of a grass happens to have a form similar to some seeds.[16]

text: Mushroom[edit]

text: A fresco in the 13th-century Plaincourault Abbey in France depicts Adam and Eve in the Garden of Eden, flanking a Tree of Knowledge that has the appearance of a gigantic Amanita muscaria, a psychoactive mushroom.[17] Terence McKenna proposed that the forbidden fruit was a reference to psychotropic plants and fungi, specifically psilocybin mushrooms, which played a central role, he theorized, in the evolution of the human brain.[18] Earlier, in a well-documented and heavily criticized study,[19][20] John M. Allegro proposed the mushroom as the forbidden fruit.[21]

text: Parallel concepts[edit]

text: This section needs expansion. You can help by adding to it. (July 2017)

text: Ancient Greeks[edit]

text: The similarities of the story to the story of Pandora's box were identified by early Christians such as Tertullian, Origen, and Gregory of Nazianzus.[22]

text: Other views[edit]

text: Islamic tradition[edit]

text: According to the Quran, Surah Al-A'raf 7:19 describes Adam and his wife in Paradise where they may eat what is provided, except that they may not eat from one particular tree, should they be considered Zalimun (wrongdoers).[23] Surah Ibrahim 14:26 describes the forbidden tree as an evil tree that is forbidden for guidance.[24]

text: Surah Al-A'raf 7:22 describes the ˈibliːs (Satan) who misled them with deception, and then it was Adam who initiated eating from the forbidden tree. Then when they tasted of the tree, that which was hidden from them of their shame became manifest to them and they began to cover themselves with the leaves of Paradise. And their Lord called out to them: "Did I not forbid you that tree and tell you; Verily, Shaitân is an open enemy unto you?" (Quran 7:19). The Quran holds both Adam and his wife accountable for eating the forbidden fruit. As punishment, they were forced to leave the garden, banished from Heaven and sent to the Earth where they were forgiven after repenting.


document_title: Oil spill

question_text: what is the worst oil spill in history

question_tokens: what is the worst oil spill in history

text: Oil spill

text: Largest oil spills[edit]

text: 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, 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, Amoco Cadiz),[4] but volume is a limited barometer 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.

text: 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 around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.

text:
Largest oil spills

Spill / Tanker
Location
Date
Tonnes of crude oil
(thousands)[a]
Barrels
(thousands)
US Gallons
(thousands)
References

Kuwaiti Oil Fires[dubious – discuss][b]
 Kuwait
000000001991-01-16-0000January 16, 1991 – 000000001991-11-06-0000November 6, 1991
7005136000000000000♠136,000
7006100000000000000♠1,000,000
7007420000000000000♠42,000,000
[5][6]

Kuwaiti Oil Lakes [c]
 Kuwait
000000001991-01-01-0000January 1991 – 000000001991-11-01-0000November 1991
7003340900000000000♠3,409–6,818
7004250000000000000♠25,000–50,000
7006105000000000000♠1,050,000–2,100,000
[7][8][9]

Lakeview Gusher
 United States, Kern County, California
000000001910-03-14-0000March 14, 1910 – 000000001911-09-01-0000September 1911
7003120000000000000♠1,200
7003900000000000000♠9,000
7005378000000000000♠378,000
[10]

Gulf War oil spill [d]
 Kuwait, Iraq, and the Persian Gulf
000000001991-01-19-0000January 19, 1991 – 000000001991-01-28-0000January 28, 1991
7002818000000000000♠818–1,091
7003600000000000000♠6,000–8,000
7005252000000000000♠252,000–336,000
[8][12][13]

Deepwater Horizon
 United States, Gulf of Mexico
000000002010-04-20-0000April 20, 2010 – 000000002010-07-15-0000July 15, 2010
7002560000000000000♠560–585
7003410000000000000♠4,100–4,900
7005172000000000000♠172,000–180,800
[14][15][16][17][18]

Ixtoc I
 Mexico, Gulf of Mexico
000000001979-06-03-0000June 3, 1979 – 000000001980-03-23-0000March 23, 1980
7002454000000000000♠454–480
7003332900000000000♠3,329–3,520
7005139818000000000♠139,818–147,840
[19][20][21]

Atlantic Empress / Aegean Captain
 Trinidad and Tobago
000000001979-07-19-0000July 19, 1979
7002287000000000000♠287
7003210500000000000♠2,105
7004883960000000000♠88,396
[22][23][24]

Fergana Valley
 Uzbekistan
000000001992-03-02-0000March 2, 1992
7002285000000000000♠285
7003209000000000000♠2,090
7004877800000000000♠87,780
[25]

Nowruz Field Platform
 Iran, Persian Gulf
000000001983-02-04-0000February 4, 1983
7002260000000000000♠260
7003190700000000000♠1,907
7004800800000000000♠80,080
[26]

ABT Summer
 Angola, 700 nmi (1,300 km; 810 mi) offshore
000000001991-05-28-0000May 28, 1991
7002260000000000000♠260
7003190700000000000♠1,907
7004800800000000000♠80,080
[22]

Castillo de Bellver
 South Africa, Saldanha Bay
000000001983-08-06-0000August 6, 1983
7002252000000000000♠252
7003184800000000000♠1,848
7004776160000000000♠77,616
[22]

Amoco Cadiz
 France, Brittany
000000001978-03-16-0000March 16, 1978
7002223000000000000♠223
7003163500000000000♠1,635
7004686840000000000♠68,684
[22][25][25][27][28]

text:
Jump up ^ One metric ton (tonne) of crude oil is roughly equal to 308 US gallons or 7.33 barrels approx.; 1 oil barrel (bbl) is equal to 35 imperial or 42 US gallons. Approximate conversion factors. Archived 2014-06-21 at the Wayback Machine.
Jump up ^ Estimates for the amount of oil burned in the Kuwaiti Oil Fires range from 500,000,000 barrels (79,000,000 m3) to nearly 2,000,000,000 barrels (320,000,000 m3). Between 605 and 732 wells were set ablaze, while many others were severely damaged and gushed uncontrolled for several months. It took over ten months to bring all of the wells under control. The fires alone were estimated to consume approximately 6,000,000 barrels (950,000 m3) of oil per day at their peak.
Jump up ^ Oil spilled from sabotaged fields in Kuwait during the 1991 Persian Gulf War pooled in approximately 300 oil lakes, estimated by the Kuwaiti Oil Minister to contain approximately 25,000,000 to 50,000,000 barrels (7,900,000 m3) of oil. According to the U.S. Geological Survey, this figure does not include the amount of oil absorbed by the ground, forming a layer of "tarcrete" over approximately five percent of the surface of Kuwait, fifty times the area occupied by the oil lakes.[7]
Jump up ^ Estimates for the Gulf War oil spill range from 4,000,000 to 11,000,000 barrels (1,700,000 m3). The figure of 6,000,000 to 8,000,000 barrels (1,300,000 m3) is the range adopted by the U.S. Environmental Protection Agency and the United Nations in the immediate aftermath of the war, 1991–1993, and is still current, as cited by NOAA and The New York Times in 2010.[11] This amount only includes oil discharged directly into the Persian Gulf by the retreating Iraqi forces from January 19 to 28, 1991. However, according to the U.N. report, oil from other sources not included in the official estimates continued to pour into the Persian Gulf through June, 1991. The amount of this oil was estimated to be at least several hundred thousand barrels, and may have factored into the estimates above 8,000,000 barrels (1,300,000 m3).

tag: ol

text: Human impact[edit]

text: An oil spill represents an immediate fire hazard. The Kuwaiti oil fires produced air pollution that caused respiratory distress.[citation needed] The Deepwater Horizon explosion killed eleven oil rig workers.[29] The fire resulting from the Lac-Mégantic derailment killed 47 and destroyed half of the town's centre.[citation needed]

text: 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;[30] 80,000 people in Coca, Ecuador,.[31] In 2000, springs were contaminated by an oil spill in Clark County, Kentucky.[32]

text: 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.

text: Environmental effects[edit]

text: In general, spilled oil can affect animals and plants in two ways: dirесt from the oil and from the response or cleanup process.[33][34] 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.[35] Oil penetrates into the structure of the plumage 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.

text: Animals who rely on scent to find their babies or mothers cannot 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, 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 imbalance. Some birds exposed to petroleum also experience changes in their hormonal balance, including changes in their luteinizing protein.[36] The majority of birds affected by oil spills die from complications without human intervention.[37][38] Some studies have suggested that less than one percent of oil-soaked birds survive, even after cleaning,[39] although the survival rate can also exceed ninety percent, as in the case of the Treasure oil spill.[40]

text: Heavily furred marine mammals exposed to oil spills are affected in similar ways. Oil coats the fur of sea otters and seals, 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.

text: 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 of the oil.

text: In addition, oil spills can also harm air quality.[41] The chemicals in crude oil are mostly hydrocarbons that contains toxic chemicals such as benzenes, toluene, poly-aromatic hydrocarbon and oxygenated polycyclic aromatic hydrocarbons.[42] 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.[43] 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.[44] 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.[45]

text: Sources and rate of occurrence[edit]

text: A VLCC tanker can carry 2 million barrels (320,000 m3) of crude oil. This is about eight times the amount spilled in the widely known Exxon Valdez oil spill. In this spill, the ship ran aground and dumped 260,000 barrels (41,000 m3) of oil into the ocean in March 1989. Despite efforts of scientists, managers, and volunteers over 400,000 seabirds, about 1,000 sea otters, and immense numbers of fish were killed.[46] Considering the volume of oil carried by sea, however, tanker owners' organisations often argue that the industry's safety record is excellent, with only a tiny fraction of a percentage of oil cargoes carried ever being spilled. The International Association of Independent Tanker Owners has observed that "accidental oil spills this decade have been at record low levels—one third of the previous decade and one tenth of the 1970s—at a time when oil transported has more than doubled since the mid 1980s."

text: Oil tankers are just one of the many sources of oil spills. According to the United States Coast Guard, 35.7% of the volume of oil spilled in the United States from 1991 to 2004 came from tank vessels (ships/barges), 27.6% from facilities and other non-vessels, 19.9% from non-tank vessels, and 9.3% from pipelines; 7.4% from mystery spills.[47] On the other hand, only 5% of the actual spills came from oil tankers, while 51.8% came from other kinds of vessels.[47]

text: The International Tanker Owners Pollution Federation has tracked 9,351 accidental spills that have occurred since 1974.[48] According to this study, most spills result from routine operations such as loading cargo, discharging cargo, and taking on fuel oil.[22] 91% of the operational oil spills are small, resulting in less than 7 metric tons per spill.[22] On the other hand, spills resulting from accidents like collisions, groundings, hull failures, and explosions are much larger, with 84% of these involving losses of over 700 metric tons.[22]

text: Cleanup and recovery[edit]

text: 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.[1]

text: Methods for cleaning up include:[49]

text:
Bioremediation: use of microorganisms[50] or biological agents[51] to break down or remove oil; such as the bacteria Alcanivorax[52] or Methylocella Silvestris.[53]
Bioremediation Accelerator: Oleophilic, hydrophobic chemical, containing no bacteria, which chemically and physically bonds to both soluble and insoluble hydrocarbons. The bioremediation accelerator acts as a herding agent in water and on the surface, floating molecules to the surface of the water, including solubles such as phenols and BTEX, 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.[54]
Controlled burning can effectively reduce the amount of oil in water, if done properly.[55] But it can only be done in low wind,[56] and can cause air pollution.[57]

text:
Dispersants can be used to dissipate oil slicks.[58] A dispersant is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, 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 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 emulsions. However, laboratory experiments showed that dispersants increased toxic hydrocarbon levels in fish by a factor of up to 100 and may kill fish eggs.[59] Dispersed oil droplets infiltrate into deeper water and can lethally contaminate coral. Research indicates that some dispersants are toxic to corals.[60] A 2012 study found that Corexit dispersant had increased the toxicity of oil by up to 52 times.[61]
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.[62]
Dredging: for oils dispersed with detergents and other oils denser than water.
Skimming: Requires calm waters at all times during the process.
Solidifying: Solidifiers are composed of tiny, floating, dry ice pellets,[63][64][65] and hydrophobic polymers that both adsorb 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.[34] 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 wild life and have been proven to suppress harmful vapors commonly associated with hydrocarbons such as Benzene, Xylene, Methyl Ethyl, Acetone 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 manufactures 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 of Louisville, Kentucky) is being used by BP in granular form, as well as in Marine and Sheen Booms at Dauphin Island and Fort Morgan, Alabama, 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.[66]
Beach Raking: coagulated oil that is left on the beach can be picked up by machinery.

text: Equipment used includes:[55]

text:
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
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

text: Prevention[edit]

text:
Secondary containment - methods to prevent releases of oil or hydrocarbons into environment.
Oil Spill Prevention Containment and Countermeasures (SPCC) program by the United States Environmental Protection Agency.
Double-hulling - build double hulls 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.[67]

text: Spill response procedures should include elements such as;

text: A listing of appropriate protective clothing, safety equipment, and cleanup materials required

text: for spill cleanup (gloves, respirators, etc.) and an explanation of their proper use;

text:
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.[68]

text: Environmental Sensitivity Index (ESI) mapping[edit]

text: Environmental Sensitivity Index (ESI) maps are used to identify sensitive shoreline resources prior to an oil spill event in order to set priorities for protection and plan cleanup strategies.[69][70] By planning spill response ahead of time, the impact on the environment can be minimized or prevented. Environmental sensitivity index maps are basically made up of information within the following three categories: shoreline type, and biological and human-use resources.[71]

text: Shoreline type[edit]

text: 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.[72] The floating oil slicks put the shoreline at particular risk when they eventually come ashore, covering the substrate 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. In 1995, the US National Oceanic and Atmospheric Administration extended ESI maps to lakes, rivers, and estuary shoreline types.[71] 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. The productivity of the shoreline habitat is also taken into account when determining ESI ranking.[73] Mangroves and marshes tend to have higher ESI rankings due to the potentially long-lasting and damaging effects of both the 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.

text: Biological resources[edit]

text: 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 bears, sea otters and whales.[71][73] Problems taken into consideration when ranking biological resources include the observance of a large number of individuals in a small area, whether special life stages occur ashore (nesting or molting), and whether there are species present that are threatened, endangered or rare.[74]

text: Human-use resources[edit]

text: Human use resources are divided into four major classifications; archaeological importance or cultural resource site, high-use recreational areas or shoreline access points, important protected management areas, or resource origins.[71][74] Some examples include airports, diving sites, popular beach sites, marinas, natural reserves or marine sanctuaries.

text: Estimating the volume of a spill[edit]

text: 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.[75]

text:
Film thickness
Quantity spread

Appearance
inches
mm
nm
gal/sq mi
L/ha

Barely visible
0.0000015
0.0000380
38
25
0.370

Silvery sheen
0.0000030
0.0000760
76
50
0.730

First trace of color
0.0000060
0.0001500
150
100
1.500

Bright bands of color
0.0000120
0.0003000
300
200
2.900

Colors begin to dull
0.00004
0.0010000
1000
666
9.700

Colors are much darker
0.0000800
0.0020000
2000
1332
19.500

text: 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.[76] 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. 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.[77]