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Petroleum and the Environment - Part 2: The Marine Environment

GLY 4241 - Lecture 15 Fall, 2014

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Deliberate Discharges

• Oil Spill – industrial discharge, cleaning tanks

• Here, the ship is deballasting

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Tanker Prestige

• The Bahamas-registered Prestige oil tanker is seen broken on two some 150 miles off Spain's coast November 20, 2002

Oil Spills –Number

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Table 16-1: Oil Spills by Year and Amount DischargedYear 7-700 Tons > 700

TonsYear 7-700 Tons > 700 Tons

1970 6 29 1990 51 14

1971 8 14 1991 29 7

1972 48 27 1992 31 10

1973 27 32 1993 31 11

1974 89 28 1994 26 9

1975 95 22 1995 20 3

1976 67 26 1996 20 3

1977 68 17 1997 28 10

1978 58 23 1998 25 5

1979 60 34 1999 19 6

1980 52 13 2000 19 4

1981 54 7 2001 16 3

1982 45 4 2002 12 3

1983 52 13 2003 15 4

1984 25 8 2004 16 5

1985 31 8 2005 21 3

1986 27 7 2006 11 4

1987 27 10 2007 10 3

1988 11 10

1989 32 13Source: International Tanker Owners Pollution Federation, 2007

Oil Spill Per Year, 1970-2013

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Tanker Spill and Tanker Traffic

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Sources of Pollution

• Relative average, annual input (1990-1999) of petroleum hydrocarbons (kilotons) into the worldwide marine environment from sources associated with the consumption of petroleum

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Torrey Canyon

• On 18 March, 1967 the ‘Torrey Canyon' struck Pollard's Rock in the Seven Stones reef between the Scilly Isles and Land's End, England. She was the first of the big supertankers, carrying a cargo of 120,000 tons of oil.

Punctuated Progress

• During the years 1982 and 1986-1988, no reported large spills or spills caused large damage claims. It should be noted that the Exxon Valdez spill of 1989 amounted to 35 kilotons, which makes it an average spill. Nevertheless, it attracted tremendous attention and will be discussed later.

• A spill occurred off Uruguay’s coast on February 8, 1997. The tanker San Jorge, carrying 370,000 barrels of crude oil, ran aground near the resort of Punta del Este.

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Oil Spills –Amount

Table 16-2: Annual Quantity of Oil SpiltYear Quantity (Tons) Year Quantity (Tons)

1970 330,000 1990 61,000

1971 138,000 1991 430,000

1972 297,000 1992 172,000

1973 164,000 1993 139,000

1974 175,000 1994 130,000

1975 357,000 1995 12,000

1976 364,000 1996 80,000

1977 291,000 1997 72,000

1978 386,000 1998 13,000

1979 640,000 1999 29,000

1970's Total 3,142,000 1990's Total 1,138,000

1980 206,000 2000 14,000

1981 48,000 2001 8,000

1982 12,000 2002 67,000

1983 384,000 2003 42,000

1984 28,000 2004 15,000

1985 85,000 2005 17,000

1986 19,000 2006 13,000

1987 30,000 2007 16,000

1988 190,000

1989 174,000

1980's Total 1,176,000Source: International Tanker Owners Pollution Federation, 2007

Natural Occurence

• The natural occurrence of petroleum in marine waters causes certain difficulties.

• Marine pollution has been defined by the United Nations Group of Experts on the Scientific Aspects of Marine Pollution (or GESAMP) as, "the introduction by (people), directly or indirectly of substances or energy into the marine environment resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities, including fishing, impairment of quality of use of sea-water reduction of amenities"

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Has Pollution Occurred?

• If human activities increase substances such as petroleum in the oceans, but the deleterious effects described by GESMAP do not exist (or are not observed) technically, no pollution has occurred.

• The oceans could be described as contaminated.

• It is also necessary to distinguish between contaminants conserved and those that are not conserved A conservative contaminant is one that has little or no natural

removal processes operating on it

These processes may be biological, chemical, or physical

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Mediterranean Pollution

• Deliberate discharges Deballasting Tank-washing by oil-tankers Discharge of bilge waters

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Barcelona Convention

• 1976 agreement to ban the discharge of oily residue in the Mediterranean

• Result – floating tar: 1969 - 37,000 μg/m2 1987 - 1175 μg/m2

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Load-on-Top (LOT) System

• Ballast water is allowed to settle before discharge

• Less dense petroleum residue rises to the top

• Ballast water is then pumped out from the bottom until only the surface oil remains

• New cargo is then pumped in on top

Effect of Anthropogenic Petroleum Spills

• In the open ocean, anthropogenic introduction of petroleum is probably a small part of the total petroleum found in the sea

• According to Davenport (1982), marine phytoplankton produce thirty times more hydrocarbons than man introduces into the ocean

• Johnston (1984) estimates anthropogenic input at 5,000,000 tons, and says that total biogenic hydrocarbon production is 1017 tons annually!

• Thus the effect of anthropogenic petroleum input into the open ocean is most likely that of a contaminant, not a pollutant

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Petroleum Degradation

Emulsification and Oxidation

• Emulsification increases dissolution

• It increases the difficulty of skimming the oil off the surface as it greatly increases the material to be dealt with.

• Oxidation also begins, forming various breakdown products

• Within a few days about 25% of the spill is lost through evaporation Generally the atoms evaporated contain 12 or fewer carbon atoms The remainder of the oil spill will gradually coalesce to form small

tar balls, usually a few millimeters in diameter.

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Tar Balls

• UCSB researchers and others have also noted that the liquid oil component of hydrocarbon seepage tends to accumulate in slicks at the sea-surface, as well as form tar balls that can end up on beaches, and even your feet!  

Ecological Effects• Since microbes are known to degrade many organic

compounds, the tar and petroleum may serve as nutrient source for some microbes.

• Large spills may cause effects similar to eutrophication in small water bodies Organisms able to use the new food source will grow rapidly

until another limiting factor causes growth to cease, and the organisms may then die quickly

In small bodies of water, this can lead to anaerobic conditions, but it is unknown what effect, if any, such microbial blooms have in the open sea

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Toxicity of Petroleum Spills

• Toxicity of petroleum spills diminishes with time• The Torrey Canyon spill of 1967 was far enough offshore

that the residual material that washed ashore was almost biologically inert

• Consequently, oil spills in cold regions may be much more hazardous.

• Biological degradation reactions in cold climates are very slow, so the petroleum spill may remain toxic for longer periods

• Slow reaction rates are a combination of low temperature, and low levels of nitrogen, phosphorous, and oxygen

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Decomposers• Many kinds of microbes to break all of the molecules

down• Certain species selectively break down certain types of

molecules• Biological degradation produces intermediate species• These intermediate species are often further broken

down by other species Normal alkanes are most readily attacked Therefore, cyclopariffins and aromatic hydrocarbons remain

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Ingestion of Contaminants

• The species accumulated often include polycyclic aromatic hydrocarbons, known powerful carcinogens

• The flavor of the flesh of edible organisms is affected Perhaps this is good, as it may serve as a

warning not to eat these particular individuals

Redox Potential• The presence of organic matter in sea-water changes

the redox potential Organic matter is thermodynamically unstable under

aquatic conditions Organic molecules may be considered as intermediates in

the complicated redox reactions present in the ocean Total organic carbon in the oceans is about 2.3 x 1017

moles carbon, or about 8% of the total carbon in the ocean The organic carbon in the oceans represents about 4.4

times the amount of carbon in the atmosphere

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Natural Oil Seep

• Natural oil seep, at the base of a sea cliff near Santa Barbara

• Asphaltum covers the beach sand with an impressive build-up

• Asphaltum, a tar-like substance, is eroded by waves to form pesky tar-balls, which are carried by longshore currents to other beaches, miles away

Oil Seepage at Sea

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Macondo Well Explosion

• An explosion at the Macondo well on 4/20/2010 caused oil to gush into the sea

• This well, in the Gulf of Mexico, was being drilled by British Petroleum from the Deepwater Horizon platform

• The explosion caused the death of eleven workers

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Deepwater Horizon Explosion Video

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Petroleum Leak Amount

• BP initially estimated that 5000 barrels of oil per day were leaking – numerous experts began to question the leak rate when they saw video

• The well was capped 7/15/2010• It was later estimated that 4.9 million barrels

(205 million US gallons) had leaked, with an initial leak rate of 62,000 barrels per day

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Use of Dispersants

• BP sprayed nearly 2,000,000 gallons of dispersant into the ocean, more than half directly into the plume

• Dispersants are designed to convert petroleum into tiny droplets, which have a very high surface area/volume ratio

• Miicrobes should then digest and breakdown petroleum

• Dispersants are toxic, and may kill microbes30

What Caused the Leak?

• After the Macondo well explosion, the Chemical Safety Board was asked to investigate and try to determine the cause of the accident

• “The CSB is an independent federal agency charged with investigating industrial chemical accidents.

• The CSB conducts root cause investigations of chemical accidents at fixed industrial facilities. Root causes are usually deficiencies in safety management systems, but can be any factor that would have prevented the accident if that factor had not occurred. Other accident causes often involve equipment failures, human errors, unforeseen chemical reactions or other hazards”

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Fifth Circuit Court of Appeals• “On September 18th, the U. S. Court of Appeals for the Fifth

Circuit affirmed the CSB’s authority to investigate the tragic April 2010 blowout and explosion in the Gulf of Mexico. The Court affirmed U.S. District Court Judge Lee Rosenthal’s March, 2013 decision that ordered Transocean Deepwater Drilling, Inc. to comply with CSB investigative subpoenas that were initially served in 2010 and 2011. In response to Judge Rosenthal’s order, Transocean sought to avoid compliance by seeking a stay of the District Court's decision. The Fifth Circuit rejected Transocean’s request for a stay, and required Transocean to produce documents in response to the CSB’s subpoenas. Transocean pursued an appeal nonetheless.

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Appeals Ruling Continued

• “The Court of Appeals affirmed in a 2-1 decision that the CSB has jurisdiction to investigate the tragedy at the Macondo drilling installation and, of course, the authority to issue administrative subpoenas as part of its investigation.  The Court’s decision follows an extensive litigation effort by the CSB and the Justice Department and affirms what the CSB has consistently maintained – that the CSB has the legal authority to thoroughly investigate the Gulf tragedy.”

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What Caused the Leak?

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