Chapter One Introduction

A vast amount of material has been written on oil pollution and its effects during the past five years. Uncertainty is a general feature of most of the reports. For example, published estimates of the total annual influx of oil into the oceans of the earth vary from 1.64 million tons to 10 million tons ().

If 10 million tons of oil were put into the sea annually and uniformly distributed over the world's oceans, the influx rate would be only six ounces of oil per square mile per day. Most oil pollution problems are due not to the overall spillage, but to the spillage of a large amount of oil in a small area in a short time.

Porricelli et al. () have estimated the quantities of oil reaching the ocean from various sources. Their estimate, as shown in Figure 1-1 and Table 1-1, is subjective at best. Automobile crankcase oil disposal is given as the largest source of oil pollution in the oceans, and Porricelli's method of calculating this pollution () is an example of this subjectivity. Porricelli estimates that on January 1, 1970 there were 207 million automobiles, trucks and buses in the world. Then he assumes that each vehicle changes oil twice a year and that each oil change involves an average of 5.5 quarts of oil, thus generating 569 million gallons of used crankcase lubricating oil each year. He then estimates (without substantiating evidence) that 75 percent of this oil-425 million gallons—enters the sea annually. It is probably impossible to estimate accurately the percentage of used crankcase oil that enters the sea. One difficulty with questionable estimates is that they are often used authoritatively in subsequent reports. For example, the environmental impact statement of the Maritime Administration Tanker Construction Program () uses Porricelli's estimate of the annual ocean pollution by motor vehicle lubricating oil.

The extent of ocean pollution by natural seepage of oil is also uncertain. An accurate estimate of the extent of natural seepage would be