Effects of Oil Spill on Our Environment

Effects of Oil Spill on Our Environment

Introduction to Oil Spills

Oil spills are the release of petroleum into the sea or inland areas and are a major threat mainly to coastal environments. In the past century, there was a notable increase in world population, in general, and in the coastal population in particular. Hence, coastal areas' vulnerability to oil spills has increased, often to the level of potential natural and human catastrophes (Caputo, 2011).

Oil is mainly exported by maritime traffic from oil-exporting areas, such as the Persian Gulf, Libya and Algeria, Nigeria, and Sudan in Africa to the major oil-importing countries, namely, the United States, Western Europe, Japan, India, and China. In the 1990s, some 3.4 million tons of oil, or 0.01% of the world's total annual oil production—about 3.6 billion tons/year, went into the sea (Caputo, 2011). Approximately, 47% of this volume was from oil spills from ships, the rest from industrial plants, sea oil drillings, and natural sources. Generally, major oil spills are caused by shipping accidents at sea, fires on tankers, or ship accidents on coastal barriers. The total risk, or the expected number of injuries and lives lost and amount of property damaged, is a function of the magnitude of the hazard—oil spill in this case; the number of potential economic and environmental assets to be affected, such as beaches, ports, nature reserves, and so on; and the vulnerability of the affected area (Adler, 2007).

Oil Characteristics

Crude oil is a naturally occurring complex of liquid hydrocarbon, which after distillation yields a range of combustible fuels. Four different types can be distinguished from the viewpoint of oil spill threat to the environment:

Light fuels, such as gasoline, kerosene, or fuel oil

Medium to heavy oil, such as ship fuels and light lubricants

Oil rich in paraffin, such as water-oil emulsion and heavy-oil lubricants

Residual oil, such as asphalt and heavy-oil residuals

The following are the oil characteristics that need to be taken into account in an oil spill: (a) density, which determines the dispersion and floating of the oil (heavy-oil density is above 0.9, light-oil density is below 0.865, and fuel-oil density is 0.84); (b) viscosity, or resistance to flow; (c) boiling point, which determines the rate of evaporation; (d) pour point, namely, the temperature at which oil is transformed into a gel, depending on the oil composition; (e) flash point, or the lowest oil temperature to maintain a layer of vapor, an important factor to reduce fire risk; and (f) dilution—light fuels are easier to dilute in sea-water but are poisonous to the living environment (Corn, 2010). Oil is an organic compound and is transformed in seawater by complex physical and chemical processes until it “disappears” completely. Light and medium oils dilute and evaporate in seawater after one day, but the heavy fractions with high viscosity may remain and are hard to dilute with dispersants. In such cases, removal of oil by mechanical means is best advised.

In a tropical climate, about 80% of the oil ...