Measuring the Effects of Man's Wastes on the Ocean

Understanding the ecological effects of municipal wastewater discharged into the ocean depends on data developed by reliable measurements. Municipal wastes are largely residential sewage flavored with industrial effluent; the amount and toxicity of the latter depend, of course, on the kind and amount of industry and the local regulations. Usually this mixture is given some level of treatment in a sewage plant at which time some of the solids (grit and sludge) are removed. The remainder may be treated by aeration, bacteria, addition of various chemicals, etc. until the final effluent is a thin but complex soup containing many fine particles. Upon discharge out the deep diffuser outfalls used in California, this liquid is immediately diluted by at least 100 to 1 forming a plume which drifts off to sea with the prevailing currents. These discharges have very little, if any, effect on man but they do have some effect on life in the sea. Now the question arises which makes this a controversial subject. Are these effects serious enough to require a major effort or are they of no more importance than the excavation of a building, the plowing of a field, or the concreting over of land to make an airport? This paper summarizes how measurements can be made that not only define the present situation but which can be used as a basis for forecasting what future effects would be if certain changes were made in the character of the wastes discharged.