Pollution - oil pollution

oil spill 

• oil spill is release of liquid petroleum hyrdrocarbons into the enviro, due to human acitivity + its a form of pollution 
• term applied to marine oil spills where oil is released into the ocean/coastal waters, can occur on land 

causes: 

• most are accidental/due to humans
• waste lubricating oil: vehicle engine oil, indistrial machine oil - washed + mixed discharges in other effluents, 
• leaks/deliberately discarded into the enviro 
• accidential releases: leakage storage tanks, oil pipeline leaks, oil rig accidents, shipping accidents - oil tanker
• oil exploration: drilling - oil pipes need be lubricated to reduce friction as bore thorugh rocks 
• be release of crude oul from tankers, drilling rigs + their by products 

oil pollution effects + impacts: 

• socio economic: fisheries, aquaculture, in shore fragile ecosystems, tourism, protected/designated areas, affect water table - potable water, irrigation 
• toxi components of crude oil e.g. benzene 
• oil coat bird feathers + animal fur, feathers stick together so lose insulating properties = hypothermia = death 
• birds clean feathers, reduces time availble to find food for themselves/young 
• oil form thin layer on surface water - reduces amount of oxygen that can dissolve from atmosphere into water = reduces survival of aerobic organisms 
• smothering, suffocation of all marine organisms 
• ingestion - animals poisoned/suffer internal damage from ingesting oil
• increased predation - oil weigh down feathers/fur making it difficult for birds + others to escape from predators 
• decreased reproduction 
• fouling of habitat 

Behaviour + fate of oil offshore: 

• crude oil in marine enviro is subject ot physical, chemical + biological processes that change composition + enviro imapct 
• weathering of crude oil invovles evaporation/voilatilization, emulsification, dissolution in marine enviro 
• fate of oil in enviro depends on composition, source, persistence

natural degredation of oil (5 forms): 

• weathering: chemical + physical changes causes oil to become heavier than water, wave action help dispserse oil 
• evaporation: lighter + more volatile molecules in oil turn into vapours thats lost, large volumes of oil lost this way 
• oxidation: oxygen combines with oil to form water soluble compounds, tar balls may form + wash up on shoreline 
• biodegredation: microorganisms break down the oil, working more quickly in warm water, different types of microbes feed on different types of oil compounds
• emulsification: formation of droplets of oil in water, slows down processes of dispersal 

oil spill treatment/clean up methods: 

• properties of oil make treatment/clean up difficult - heavy crude oil, sticky, viscous 
• behaviour = difficult to disperse 
• enviro conditions impact: warm temps contribute to evaporation of large quantities of volatile compounds, enable bacteria to breakdown oil quickly, wave action help degrade + oxygenate the oil 

control + prevention of oil release:

improved tanker design

• twin engine/rudder/fuel tanks - pairs of essential equipment in case one fails, otherwise tanker may drift with wind, crash onto rocks/capsize 
• double hull…