4.10. Oil spills
Oil spills from tankers or crashes on oil wells are the worst sources of oil pollution in world seas and oceans. It is estimated that 2.3 million tons of oil per year is poured into the sea. Oil drains oxygen from the sea and thus destroys the plant and animal world in it. Many birds and marine organisms are trapped in oil spillages on the shores, and then they die because of inability to breathe or oil poisoning. Removal of oil stains is costly and time-consuming and is not fully effective, so such incidents leave permanent consequences to life in the sea.
Negative polluting effects that oil spills have on the environment and living organisms, are caused by discharge of various organic compounds that make up crude oil and oil distillate products, the majority of which include various individual hydrocarbons. Hydrocarbons are made exclusively from carbon and hydrogen atoms which bind together in various ways. Other individual compounds that are present in crude oil and oil discharges include sulfur, nitrogen and/or oxygen atoms. These organic compounds may affect the wildlife (including fish and birds) and humans in various ways such as direct contact with the skin, through inhalation of volatile components or ingestion of contaminated water and/or particles. Oil can also smother some small species of fish or invertebrates and coat feathers and fur, reducing birds’ and mammals’ ability to maintain their body temperatures. Additionally, some of the oil hydrocarbons such as PAHs bioaccumulate in fish and other organisms and may concentrate many times more than in water or other media. This way, they enter the food chains also affecting human health through consumption of contaminated food.
Transportation of petroleum and petroleum products causes everyday risks for possible pollution of the sea. Although the large oil spills raise most media attention, the biggest danger are smaller and almost everyday outpourings during the loading or unloading the oil for the boat traffic. Most waste oil in the ocean consists of oily stormwater drainage from cities and farms, untreated waste disposal from factories and industrial facilities, and unregulated recreational boating. Ultimately, the effects of any oil depend on where it is spilled, where it goes, and what animals and plants, or people, it affects.
Most of the common methods used for cleaning up oil spills are ineffective. In many cases the chemicals used in these cleaning processes are also damaging marine life. Oil spill countermeasures to clean up and remove the oil should be selected and applied on the basis of many interrelated factors, including ecological protection, socioeconomic effects, and health risk. It is important to have contingency plans in place in order to deploy pollution control personnel and equipment efficiently.
4.10.1 What are the main sources of oil pollution in the sea?
The sea is constantly threatened by the presence of human's machines and fuel extraction facilities.
The majority of oil pollution comes from the sea itself thought.
In fact, more than 40% of the oil pollution comes from natural seeps in the oil reservoirs in the seabed, but it gets cleaned by microbes grown in the sea, so the effects can be contained when the ocean is in good health and in conditions to do it.
The other main sources are caused all by human hand.
An example is the discharge of oil consumption from the ships and from the land-based and urban vehicles usage. Oil gets in the sewers or rivers and then is expelled in the sea. It represents almost forty percent of oil pollution (About 37%).
Another human-caused pollution comes from incidents in coastal facilities and fuel transport ships.
By now the incident counter is above 10000. Every year the sea needs to absorb more than 2.3 million tons of oil.
These three main reasons cause a lot of casualties in the marine environment. The chemical compounds present in the oil takes oxygen from the sea, causing death either by poisoning or lack of breath.
The pollution presents himself in other forms too, that causes 3% of the remaining sources of pollution.
It can present itself in a gaseous form. The gas pollution comes from vehicles or industrial facilities in the land, then this gas gets in the ocean through the air and gets trapped in the water cycle.
The other form in which it presents is in a solid form, the trash, and other chemical scraps derived from oil get thrown in the water sources, like rivers or directly in the ocean, where they cause pollution by their decomposition.
4.10.2 Why are oil spills fatal to most of marine organisms?
Oil spills are fatal to most of marine organisms because they drain oxygen from the sea and thus destroys the plant and animal world in it. Many birds and marine organisms are trapped in oil spillages on the shores, and then they die because of their inability to breathe or oil poisoning.
Moreover, oil destroys the insulating ability of fur-bearing mammals, such as sea otters, and the water repellence of a bird's feathers, causing the exposure of these animals to the harsh elements. Without the ability to repel and insulate from the cold water, birds and mammals can die from hypothermia.
Many birds and animals also ingest oil when they try to clean themselves, which can poison them.
Fish and shellfish may not be exposed immediately but can encounter oil if it is mixed into the water column. When exposed to oil, adult fish may experience reduced growth, enlarged livers, changes in heart and respiration rates, fin erosion, and reproduction impairment. Eggs and larval survival are negatively affected by the presence of oil just as well.
The adverse consequences on aquatic life are also related to the accumulation of persistent and bio accumulative components of oil in the tissues and bodies of marine organisms (fish), which has the potential to induce a variety of health and reproductive problems, leading in some cases to mass mortality events within marine life in general. The unavailability of food is another issue when mass mortality events occur.
We can observe similar issues also for the higher organisms on the food chain (which consume other smaller organisms), oil spills can seriously affect birds and marine mammals, as well as bigger fish. The gradual and additive accumulation of elevated concentrations of oil pollutants through combined exposure to a polluted environment and polluted food (with higher pollutant concentrations than in ambient environment) is the main cause of this phenomenon.
4.10.3 Describe methodes of oil stains removal from marine animals.
The intensive consumption of oil that society requires for its needs, entails a high environmental risk, especially during transport. The damage also refers to specimens or colonies of birds and marine mammals that, hit by a "black tide", end up stranded on the coast, as well as sea turtles and their nests dug on the beaches. The handling of the affected specimens presents difficulties and dangers both for the animals, which may be injured or undergo such stress as to compromise the possibility of recovery, and for the specialized volunteers who take care of their decontamination and recovery.
The oil in contact with the plumage of the birds disarticulates the delicate structure causing two immediate effects, loss of impermeability and loss of thermal insulation capacity. The birds that come into contact with oil products in the sea die by drowning because their feathers become impregnated with water, while for those specimens that are able to reach the mainland the cause of death is hypothermia, associated with the high toxicity of the product. Contaminated birds are easily identifiable because they are covered in black and sticky liquid and, if they still have energy, try to clean the oil with their beak. The specialized personnel after having transported the animal in a suitable structure, wears suitable clothes, to avoid getting wet, getting dirty, to protect themselves from the sudden movements of the bird and from contamination, for example very long latex or rubber gloves, an apron or gown and waterproof boots. In a large tank, they mix 1% mild detergent with warm water. The heat should stabilize the internal temperature of the bird (39.5-40.5ºC). Very soft toothbrushes and cotton buds are usedto gently remove dry oil from the eyes and head area. When the water in the tank becomes dirty, the bird is moved to a clean tank filled with water and detergent. The bird can be considered clean when the water in the tank is clear.
4.10.4 Chemical composition of oil spills
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. When oil is released into the sea, not only it increases pollution, but it is also difficult to clean. In fact most of the methods for cleaning oil spills are ineffective, and often damage the marine life and environment. So these countermeasures should be applied depending on interrelated factors like: ecological protection, socioeconomic effects and health risks. Crude oil is a mixture of hydrocarbons, but each kind has a different composition of molecular compounds, for example: sulphur, nitrogen, oxygen, metals, and other elements. Oil originates from the deepth of the ground, it is created from leftovers of animals and plants; heat and pressure also contribute to its formation. As oil is a hydrocarbon is principally composed by hydrogen and carbon. Aromatics and alkanes are the two principal types of petroleum hydrocarbons. The first ones are the most dangerous and toxic for the marine environment. Instead alkanes are biodegradables: there are some microorganisms which can eat, like food, these compounds. The unique elements that are shared by all crude oils are: benzene, toluene, and xylene. The refining of crude oil is useful for creating for example fuel oils without altering its molecular structure. Instead in order to create petrochemicals we need to recombine different chemical compounds, that can be extracted from crude oil.
4.10.5 What are the three main ways that organic compounds can affect wildlife and humans?
First of all, the effect of organic compounds on wild life and on humans is caused by the high concentration of these compounds in the air and in the water (such as oil) which spreads quickly through winds, acid rain, and surface water. This presence caused by accidents and pollution and can often cause permanent damage to the whole ecosystem.
The three main ways that organic compounds may affect the wildlife and humans are the direct contact with the skin, the inhalation of volatile components and the ingestion of contaminated water or particles.
Direct contact with the skin is the most evident way, where you can clearly see the devastating effects of organic compounds on animals. For example, oil can suffocate some small species of fish or invertebrates and coat feathers and furs, reducing the ability of birds and mammals to maintain their body temperatures.
Exposure to volatile organic compounds (VOC) , instead, can induce a number of harmful effects on human and animal health.
In fact, humans who have been exposed to an excessive amount of volatile organic compounds are more likely to contract diseases such as bronchial asthma, myocardial infarction, cancer or lung cancer.
Even the ingestion of organic compounds (through water or other animals and plants) can cause very serious damage to the body that has ingested them. For example, some organic compounds such as some of the oily hydrocarbons such as PAHs accumulate in fish and other organisms and can concentrate many times more than in water or other media. This way, they enter the food chains, affecting not only the health of other animals but also human health through the consumption of contaminated food.
4.10.6 How can some oil hydrocarbons enter the food chain?
Hydrocarbons from mineral oils are chemical compounds derived mainly from petroleum, but also synthesized from coal, natural gas and biomass. Generally, these substances are found in the form of complex mixtures of hydrocarbons, some of which can play a toxic action on living organisms.
A potential source of pollution comes from recovered paper used for the production of cardboard, which also includes printed newspapers and most of the inks used for printing contain mineral oils. Until now, it has not been possible to adequately remove these inks during the recycling process, with the result that they can remain in food packaging made with recycled cardboard.
International agencies hypothesize that the transfer of mineral oil hydrocarbons from packaging to foods may be greater in foods with a large surface, such as flour, semolina, rice, breadcrumbs or breakfast cereals. Even high-fat foods like butter or cocoa can be contaminated. Other potential sources of food contamination are environmental contamination, lubricants and exhaust gases from food harvesting and production machines.
The CONTAM group of the European Food Safety Authority (EFSA) concluded that, in the field of mineral oil hydrocarbons, there are different potential effects on human health. A potential role of carcinogenicity and genotoxicity is attributed to the aromatic hydrocarbons of mineral oils, while some saturated hydrocarbons of mineral oils can accumulate in the tissues and cause adverse effects on the liver of a specific stock of animals.
4.10.7 Small oil spills � everyday danger
Catastrophes often occur regarding the fall of oil in water that pollutes the environment and the animals that inhabit it. Oil spills can be caused by the accidental or intentional release of any form of oil during any phase of the oil production process, from drilling, refining or storage to transportation. Many oil-soaked birds and marine animals in distress are reported after an accident, helicopters are watching migrating whales trying to avoid shine, fishing and shellfish harvesting in the area are closed. Thus, all spills represent a serious danger to the delicate coastal ecosystem. In addition to pipelines and oil tankers we must consider other sources of oil, maybe not as big, but equally important. In fact, even more oil flows unnoticed into coastal waters from small leaks and spills of commercial vehicles, recreational boats and other sources. Often these small spills can go unreported, they receive almost no attention at all and, consequently, they are rarely cleaned up. For example, spills of less than 100,000 gallons are classified by the Coast Guard as minor or moderate, even if their consequences are not. Small spills introduce persistent, toxic oil into our waters. Even trace amounts of oil can damage marine life at fragile stages and compromise the health of local or global aquatic ecosystems. Just a few molecules of oil can kill a fish or cause air-breathing creatures like dolphins and turtles to contract fatal health issues. Cumulatively, small spills also can undermine jobs and recreational pursuits that depend on clean water. Though it is unclear exactly how much oil goes into the ocean from routine runoff, estimates range as high as 588 million gallons per year, a lot a potential damage that does not make the news. But oil spills can also occur naturally: oil is released into the ocean from natural oil seepage onto the seabed. Oil can spread very quickly, if it is light, but heavy oil can also spread quickly in a large spill. The oil slick aff
4.10.8 What factors determine the effects of any oil spill?
Sometimes the oil spills out accidentally from oil tankers and this causes pollution in the ocean. Sometimes, instead, there are people that pour in sea oil's refuse in order to not pay for its digest. In fact, 20% of the total pollution is caused by these actions.
After the spill, the oil widens quickly above the surface. Lately, the oil evaporates and, on the surface, some banks remain. These banks “travel” around the world through the current. Some of these banks create solid layers and cause very harmful effects on marine organisms.
Inter alia, marine birds' plumage gets dirty with oil. The oil reduces the capacity of thermal insulation and makes feathers unsuitable for swimming and flying. When the birds try to take off they accidentally eat it and this causes poisoning (the oil spoils the kidneys, the liver and the digestive system). Besides the birds also the marine mammals are at risk. They show symptoms similar to those of birds. In particular, the fur of sea otters and seals loses its power of thermal insulation causing hypothermia.
Another situation present itself when the banks arrive on the coast. Here, they can destroy sensitive ecosystems like coral reefs and cause serious damage to fishing. It is then through fishing that even humans can poison themselves.
An alternative to oil, more ecological and sustainable, are renewable resources. In effect, energy can be harvested from renewable resources that are naturally replenished as for example sunlight, wind, rain, tides, waves and geothermal heat.
Therefore, we should use these resources so that we can help the planet and have a life and a hospitable environment to live.
4.10.9 What factors should be considered when selecting the clean up methodes for oil spills?
There are various methods to clean up an oil spill, here we present and explain some of them.
Oil booms: Oil booms, also refereed to as containment boom, is a temporary floating barrier designed to contain an oil spill.
Use of sorbents: organic and inorganic materials that are able to suck and absorb the oil from the surface of the water leading to an oil spill cleanup.
The burning in-situ: burning of the oil on the site where the spillage has occurred. The most important disadvantage of an on-site burning is that the exhaust that is released contains toxic particles that can cause damage to the oceanic air in addition to the marine life-forms.
Use of hot water and huge force: the huge force of the hot water is used to push the oil back into the water where the oil spill clean-up operation will take place.
Using dispersants: this method involves using chemical agents to disperse the oil spillage in the water. For example, fertilizers help to hasten the growth of micro-organisms which help to diffuse the components of the oil spilt in the water.
Skimming: skimming involves the removal of the oil spillage from the surface of the water with the help of tools and equipment. The most important aspect to be noted that only lighter oils can be separated and removed from the water with this technique.
Manual labor: people in the coastal areas and beaches can help the operation by using simple tools like spades and shovels to remove and isolate the affected area.
Technological aid: if it is not possible to carry out the oil spill cleanup operation on situ then it can be taken to labs and other equipped areas where the oil can be separated from the sand and other items generally found in the beaches and coastal areas.
Natural methods: The oil’s particles, in time evaporate because of the constancy of the elements. This is the most cost-efficient and the slowest method of cleaning up oil spills.