On the basis of this review, a general assessment will be expressed on the question 

 whether efforts to manage pollutants to this estuary are sufficient. 



POLLUTION PROBLEMS AND PROGRESS 



It is impossible to quantify the total set of pollutants reaching a large estuary under 

 intensive use. It is difficult even to summarize them in general terms, with reasonable 

 assurance that all anthropogenic materials and conditions injurious to present and 

 potential uses of the system, i.e., all of the pollutants, have been included. A study of 

 potential industrial chemicals, based on permits issued and on combined knowledge 

 of chemical engineers, indicates that at least 545 compounds must be "disposed" of 

 (GCA, 1979). In this case, there is good evidence of the input of hundreds or perhaps 

 thousands of chemical compounds, plus pathogenic organisms, sediments, solid 

 matter, color, heat, radioactivity, and materials that place demands on the oxygen 

 supply in the Bay. The principal detrimental introductions merit comment, with 

 emphasis on progress achieved and problems remaining. 



Polluting materials and conditions are not introduced in neat and discrete cate- 

 gories. The content of the following subsections necessarily overlaps, but the 

 groupings may be helpful in reviewing a tangle of issues. 



Sewage 



The scale of pollution problems from sewage is determined by the size of human 

 population and related industrial activity, the composition of material entering 

 sewage treatment plants, the types and degree of treatment, the quantity and pattern 

 of release of liquid effluents, the placement of solid residue, and the total character of 

 the receiving waters. All of these factors vary throughout the Chesapeake Bay 

 system, but there is an increasing body of knowledge about magnitude and effects 

 from these complex materials. The problems created by increasing release of par- 

 tially treated sewage into the tributaries and main stream of the Chesapeake have 

 long been recognized (Corps of Engineers, 1974; Corps of Engineers, 1977; Cronin, 

 L„ 1967; Ellis, 1973; Fish and Wildlife Service, 1970; McKewen, 1972; Schubel, 

 1972). They are concentrated near the metropolitan areas at Baltimore, Washington. 

 Norfolk-Newport News-Hampton, and Richmond, but may appear near any 

 population center, as in the Patuxent River where no city exists but where treatment 

 plants concentrate regional wastes and add them to agricultural drainage. The 

 multiple effects of domestic wastes on uses of the Bay are illustrated in Figure 4 (Ellis, 

 1973). 



The magnitude and trends of sewage input are partially documented. The most 

 comprehensive description and summary was produced in 1974 for all tidal waters of 

 the Bay system (Brush, 1974). At that time, 35 plants using primary treatment and 

 207 employing secondary treatment released 945 million gallons per day (mgd) of 

 treated wastes into the Bay that, when combined with 360 mgd from the Susque- 

 hanna, was 2.8 percent of the total freshwater input. The Corps of Engineers' Future 

 Conditions Report projects that municipal wastewater treatment will increase (for 

 the defined Bay region) from about 950 mgd in 1975 to about 1 ,770 mgd around the 

 year 2000- an 85 percent increase (Corps of Engineers, 1977). Other numbers are 

 available, but they are not comparable with these because only the report by Brush is 

 based on both scanning of permits and direct observation of many of the plants. 



The only major sewage treatment system providing advanced waste treatment is at 

 Blue Plains, near Washington, D.C., with a design capacity of 309 mgd (Corps of 

 Engineers, 1977). Advanced waste treatment is planned for several other sites, but 

 review of costs against provable benefits is causing reassessments (Jensen, 1976). 



In specific tributaries, estimates have been made of total loading. About 25 

 percent of the freshwater at the mouth of the James River is from sewage outfalls 

 (Austin, 1979). For the Patuxent River, one estimate indicated that 74 percent of the 

 low freshwater flow to the estuary in 1980 consisted of treated sewage. This is likely 

 to increase to 84 percent by the year 2000 (Wilson. 1977). 



22 



