f oil each year. Moreover, that estimate comprised a range, the upper end of which amounted to over 2 billion gallons (Leahy & Colwell, 1990, p. 305). In addition, of the 1.3 billion gallons of used oil generated annually, only about 57% is recycled and only about 10% of do it yourself oil changers recycle (Arner, 1992, p. 69). These releases can result in severe environmental damage and adverse human health effects.
Oil which enters the marine environment consists of a complex mixture of compounds. Often these substances are of variable toxicity. In the ocean, crude oil typically breaks up into three main components: the volatile, floating, and sinking components. The volatile component quickly evaporates into the atmosphere and dissolves into the water column. It mainly affects organisms like plankton. In contrast, it is the floating component that pollutes the shoreline. This component harms birds and marine mammals. Thirdly, sinking oil may adversely affect subtidal ecosystems (Suchanek, 1993, p. 511 512).
On land, the production, refining, and transportation of petroleum products has created thousands of contaminated sites (Mallard et al., 1993, pp. 18). In fact, diesel contaminated soil is a major problem currently facing today's railroad industry. The oil pollution at such sites sometimes achieves an equilibrium of sorts. Different petroleum phases which occur may include the following: (1) adsorbed to soil particles; (2) dissolved in the pore water; (3) as vapor in the soil gas or pore air; and (4) as immobile, or residual, immiscible phase liquid in the pore spaces. Distribution of different oil components between these various phases tends to be a function of their prevalence in the contaminant mixture and their partitioning properties (Williams et al., 1990, p. 220). In addition, at many polluted sites, hydrocarbon contamination may have reached local ground water. By migrating into drinking water...