One of the striking developments of 1970 was the dramatically increased awareness of environmental problems. In an election year, concern about the environment was a fail-safe issue for politicians. The problems caused by coastal water pollution directly involve that 45 per cent of the American population which lives in states bordering the 17,000 miles of sea shore and the Great Lakes. Although they may not themselves have caused them, maritime enterprises often must contend with massive and intractable environmental problems.
As with any issue discussed primarily on the front pages of newspapers and on television newscasts, it is often difficult to separate what is known from what is simply asserted, to assess the technology involved, and to evaluate remedies.
The United States is not the only country with such problems; some countries, especially in Europe, have been dealing with them over many years; other countries, including underdeveloped ones, are just now recognizing the problems. Lack of knowledge about the coastal ocean in all these areas handicaps efforts to solve existing problems or prevent future environmental deterioration.
What is Pollution?
An assessment of pollution involves value judgments. To say that some part of the environment—air, water, or land surface—is polluted, indicates that some aspect of that environment has been changed so that it now fails to meet the criteria necessary for some accustomed use. Turbid water covered with oil is obviously unsuited for swimming. Pollution is long lasting in its ill-effects, and becomes widely distributed by the forces of nature and the work of men.
There are several aspects to this value judgment that make pollution problems difficult to handle. First, there is often no agreement on the underlying value structure that forms our judgment. Second, many aspects of pollution are subtle and difficult to measure. Consequently, scientific data are often difficult to acquire. Third, pollution frequently affects aspects of our life, such as the aesthetic side, to which it is difficult to assign value or costs. Therefore pollution, pollution control, and pollution abatement initially fall outside the workings of a market-oriented economy and are subject to governmental regulation and control.
In this discussion, I will use three criteria for environmental quality:
1. Does the environment insure survival?
2. Does the environment prevent disease and accidents?
3. Is the environment comfortable and aesthetically pleasing?
Not one of these is new, but the various criteria are commonly not differentiated in discussions of environmental quality. Those aspects of the environment where public health is involved justifiably receive priority treatment. Often where the amenities are involved (our third criterion), the priority is frequently lower.
We must not, however, underestimate the importance of environmental amenities. People obviously value environmental amenities, for they are quite expensive.
For instance, waterfront real estate on Long Island alone is valued in the billions of dollars. Decreased water quality costs these property owners money in a very real sense. This close relation between aesthetics and economics partly explains the deep-felt concern about environmental matters.
Of course there are many other important factors involved in the pollution of coastal waters concerning the first criterion of survival, such as its effect on the food we eat, the water we drink, and the air we breathe. For example, discharge of municipal and industrial wastes make it necessary to declare the shellfish in 1.2 million acres, or eight per cent of the nation’s shellfish grounds, unsafe for men to eat. Lake Erie, a major source of water and food, has aged in the past 50 years as much as one would expect from 15,000 years of natural aging.
The Coastal Ocean
Considering the immense volume of the ocean and the relatively puny amounts of wastes generated by man, it is surprising indeed that these wastes cause such profound changes in harbors and in the coastal ocean.
To understand why we face environmental problems in estuaries and the coastal ocean, it is necessary to consider some aspects of that part of the ocean, which behaves quite differently from the open ocean.
The coastal ocean is that shallow part overlying the continental shelf, the submerged margin of the continent. In general, and in sharp contrast with the open ocean, where typical depths range from two to three thousand fathoms, and distances are measured in thousands of miles, the continental shelf is less than 100 fathoms deep and 50 miles wide; thus the coastal ocean is relatively shallow and narrow. Consequently there is a limited amount of water in the coastal ocean to dilute wastes flowing into it.
The coastal ocean is also much more complex than the open ocean because of its embayed margins, and the harbors and estuaries along those margins. The complex coastline geography, combined with the shallowness of the coastal ocean and off-shore topography, restricts water circulation. Therefore, materials do not mix as readily, nor are they as easily dispersed in coastal waters, as they would be if introduced into the open ocean.
Coastal ocean currents also tend to isolate their water area from the open ocean. In general, coastal currents parallel the coast so that materials introduced at any point tend to flow along the coast, rather than out to sea to mix with open ocean waters. For example, materials discharged from New York Harbor tend to flow southward parallel to the New Jersey coast much of the year. This coastwise circulation generally keeps wastes near the shoreline.
On the Atlantic Coast of the United States, the separation between the open and coastal ocean circulation systems is especially well-defined. A “cold wall” separates the warm waters of the Gulf Stream system offshore from the cooler waters along the coast. On the West Coast of the United States, this boundary is not so sharply marked.
Rates of water exchange across the coastal ocean and the processes controlling this exchange are poorly known for most coastal areas. Subsurface water movements, as distinguished from the lateral circulation just mentioned, in most parts of the coastal ocean also tend to isolate coastal water from the open ocean and to cause it to retain wastes. Along U. S. coasts, except for California, the supply of fresh water from run-off and precipitation normally exceeds water lost from the ocean surface through evaporation. This results in an estuarine-like circulation (so-called because such circulation systems are especially well-developed in estuaries).
In an estuary, fresh water from rivers flowing into the estuary forms a less dense, relatively low salinity layer on top of the saltier, denser seawater beneath. This low salinity layer flows generally seaward, mixing all the while with the saline solution coming from below. Between the top layer of fresh water and the underlying salt water is formed a barrier, called a pycnocline, which results from the marked change in density as you go from one layer to the next. This pycnocline functions as a floor for the fresh water and a one-way valve for the subsurface layer waters to mix upward. The removal of salt water from the subsurface layer in turn causes a subsurface current to bring ocean water in toward the land. Thus estuarine circulation is a two-way street. The seaward-flowing surface layer removes fresh water; the subsurface layer brings salt water in to replace that carried away. However, while distinct layers form in warm summer weather, in winter strong storm winds mix the top and bottom waters, thereby destroying the pycnocline.
This circulation profoundly influences the behavior of materials in the coastal ocean. For instance, particles settle out of the surface layers and are caught by the landward moving subsurface waters. The suspended particles thus tend to remain in the waters over the continental shelf. Particles move very slowly, if at all, across the coastal ocean.
This same estuarine-like circulation system also tends to retain nutrients and other materials used by organisms for their growth. First, nutrients (principally phosphates and nitrates) are taken by phytoplankton, which are minute floating plants. Then when the organisms die and decompose, the nutrients are returned to the waters. However, the organism eventually sinks through the seaward-moving layer and falls into the subsurface landward moving layer. There, like other particles, it tends to remain in the coastal ocean. Thus, both the estuarine circulation and the mixing caused by wind and the tidal effects in nearshore waters returns the nutrients to the sunlit surface layers where they again fertilize phytoplankton growth. Another aspect of the effect of the pycnocline on problems of pollution is its effect in the case of waste heat discharges, sometimes called thermal pollution; for the higher temperature of the discharge tends to make these waters less dense, which, in turn, inhibits mixing with sea water underneath. Because of its higher temperature, the discharge readily loses its ability to retain dissolved oxygen and increases its rate of consuming dissolved oxygen, making it a poor environment for some aquatic life because of its elevated temperature and low dissolved oxygen content. Such conditions may act as a stimulant for the undesired superabundance of algae, often called an algal bloom. In short, the estuarine circulation prevailing along most of the coast of the United States does not readily move waste discharged to its waters out to the open ocean. Only those wastes that are dissolved in sea water and do not become associated either with particles of sediment, nor with organisms, readily escape to the open ocean.
Sources of Coastal Water Pollution:
Environmental deterioration generally stems at least in part from the disposal of waste. It is surprising that when we rid ourselves of the waste from a production cycle, greater tonnages are handled than the raw materials themselves initially weighed. We do not consume: we merely change, use, and discard. We are not very good at discarding.
Wastes going to coastal waters come from many sources, including domestic sewage, industrial wastes, and discarded products.
There are other important sources of waste including discharges from ships and boats. Except from disasters, such as the stranding of the Torrey Canyon, these discharges tend to be smaller, discontinuous, and more dispersed than the large volume discharges which originate ashore. They have two principal elements: fuel and refuse. Unburned fuel and fuel additives from small boats are a large part of this kind of pollution. They include, for example, lead hydrocarbons, which form a film covering the water of coves, harbors, or inlets affecting all their marine life. Metals in fuel additives affect marine life unfavorably. Refuse discarded from ships and boats can be found littering the shores near every population center along the coast. Sewage discharge from small vessels are under scrutiny, and New York State, for one, recently prohibited the discharge of sewage from boats, requiring each craft to carry holding tanks, and to empty those tanks into sewage facilities ashore.
Wastes, wherever they originate, are discharged to the atmosphere, to the water, and to land surfaces. Waste disposal is especially troublesome in coastal urban centers where land for traditional waste disposal operations, such as sanitary landfill, is limited or completely unavailable. Also there are often questions of jurisdiction. Coastal waters are usually troublesome areas in which to define jurisdiction, and environmental problems cut across many political divisions and subdivisions.
Wastes are materials unwanted by their producer. The material may have value to someone, but if the producer does not require reimbursement when the material is removed, it is considered a waste. Wastes are commonly segregated according to their physical characteristics as gases, liquids, or solids. Quite frequently different agencies have responsibility for disposing of parts of the wastes generated. Wastes from the same operation go to separate agencies for disposal. Some wastes may not be collected at all.
One aspect of the waste problem arises from our society’s orientation toward production, generally ignoring the resultant wastes. In fact, the criteria most commonly used for the general state of health for the economy and the nation is the rate of increase in the Gross National Product. Little consideration is given to the problem of the gross national waste generated in that production. Usually the costs associated with the disposal of waste are not borne either by the waste producer or by the consumer of the product which generated them. Instead they are widely distributed, often in the form of environmental deterioration. An economist would say that these are externalities, that is they are not considered in establishing costs.
It should also be pointed out that traditional classifications of wastes as gas, liquid, or solid are not always useful. We are not dealing with fixed kinds of wastes but an interdependent system of waste generating activities. Depending on economic considerations, political decisions, and available technology, it is possible to alter substantially the mix of wastes. Household wastes include solids, which may be buried in landfill or incinerated. When burned, much of the waste is emitted to the atmosphere as gas, leaving a small amount of ash to be buried, and waste heat is discharged to the air or water. On the other hand, if household refuse is ground and combined with sewage in the present sort of facilities, the resulting waste would be primarily a liquid waste. Finally, there is the option of reclamation. Again, sewage solids and wet garbage might be combined and composted to make soil conditioners. Another solution is recycling the basic material of a product, for example, metals and other solids, including glass. High labor costs, low raw materials costs, and public health considerations limit waste recycling in the United States at present. Solids are probably the irreducible limiting form of wastes.
In short, our present waste disposal problems and accompanying pollution result from a poorly managed flow of materials through our economy. Our attention has been focused primarily on first cycle production; the wastes have been left to accumulate and to pose environmental problems.
History of Waste Pollution Problems
Man has been troubled by his wastes throughout his history, especially as a city dweller. Imperial Rome had problems with waterborne sewage. In 1273, Edward I banned the burning of coal in London to alleviate air pollution. Because of problems caused by river pollution in 1388, Richard II forbade discharging waste into the rivers.
In many respects our present way of handling wastes differs little from those used in earlier times. In moving solid waste the truck and bulldozer are the major innovation. The most acceptable and usually the cheapest solution is to take refuse, garbage, and rubbish to the edge of town, compact it slightly, and cover it with dirt in a sanitary landfill.
In the United States and Western Europe, the handling of sewage has changed drastically in the past hundred years, primarily in response to public health problems. Our present waterborne sewage system dates from the mid-nineteenth century. In ancient times, sewers carried storm run-off and some incidental wastes. Local ordinances normally forbade sewage discharge to these sewers. This situation did not change until 1815 in London and around 1880 in Paris. Many underdeveloped countries still rely primarily on handling the wastes as solids, especially in rural areas.
In the mid-nineteenth century, investigations of sanitary conditions in Great Britain led to the development of our present waterborne sewage system. So far as we know, the first sanitary sewers in the United States were installed in Chicago about 1855. Because of our present water-carriage sewage system, waterborne diseases (cholera, typhoid, paratyphoid) have been eradicated in the United States and, indeed, in much of Western Europe. Sewage treatment plants, which we will discuss later, have reduced the impact of these waterborne wastes on the rivers or harbors to which they are discharged.
Despite the advances made in public health over the past century, many environmental problems remain. In the United States, the first public health surveys made around 1910 and 1912 showed that the Great Lakes, the Potomac River, and the Ohio River were polluted. In 1970, nearly 60 years later, these areas still remained as major environmental problem areas. Even the public health successes have not been without their own attendant problems. Some of the environmental difficulties we now face result from only a partial solution to these early problems.
Sources of Waste in the United. States
Waste disposal problems are not unique to coastal regions. Prodigious quantities of wastes are generated throughout the continent. The solids generated in the United States in 1969 are estimated to have exceeded 3.5 billion tons. The largest waste source was agriculture, which generated more than 2 billion tons, including animal manures and crop wastes. The second largest source of waste was the mining and processing industry, which generates wastes at the rate of approximately 1.1 billion tons each year. (This is expected to rise to approximately 2 billion tons by 1980.) During the past 30 years, more than 20 billion tons of mineral wastes have accumulated as huge piles of slag and mounds of mill tailings, most of them adjacent to the mine or mill from which they came. Acid wastes draining from mines have destroyed an estimated 11,000 miles of streams in the United States. Wastes from both agriculture and from mining doubtlessly reach the coastal ocean. But with our present limited knowledge, it is impossible to distinguish agricultural and mining wastes from those dumped into rivers by municipalities along their banks. Moreover, it is thought that agricultural waste water run-off remains mainly local in its effect, with pesticides such as DDT finding their way out to sea by transportation in the atmosphere. Thus agricultural run-off has little effect on coastal waters.
It is interesting that such wastes continue to pose problems for a long time. The California Gold Rush of 1848 generated enormous piles of wastes as a result of the hydraulic mining in valleys of the Sierra Nevada. Gravels and sands left behind by Gold Rush miners, when they washed gold-bearing deposits through their sluices, have washed into San Francisco Bay and have substantially reduced its water volume.
However, the waste problems of the coastal ocean are primarily associated with coastal cities. In particular we will pay attention to municipal sewage and to dredged waste. As we have already noted, these are by no means the only wastes generated in urban areas. Cities also produce prodigious quantities of solid wastes including refuse, garbage, and rubbish. But unlike sewage and dredged wastes, these materials are not regularly taken out and dumped in the coastal ocean. Statements of policy made in October 1970 by the Council on Environmental Quality make it unlikely that solid wastes will be discharged there in the future.
The production of solid wastes is increasing substantially. With the rise of new industries, and changing marketing techniques such as disposable packaging, the per capita generation of solid wastes has greatly expanded. In 1920 an average of 2.7 pounds of solid wastes was collected daily from each person in the United States. In 1969 this figure had risen to 5.3 pounds. It is estimated that by 1980 per capita waste collection will be 8 pounds per person per day. Not all the wastes generated are collected. Uncollected wastes (abandoned automobiles, discarded cans) can be seen along highways and streets near major cities.
Sewage Wastes
Because of its public health aspects, sewage has been one of the wastes with which we’ve had the most experience dumping in the coastal ocean. Despite the long history of working with these materials, there still is much to be learned about reducing the impact of the 8.3 billion gallons discharged daily into coastal or estuarine waters.
Municipal sewage plants receive domestic sewage and other wastes, including industrial wastes discharged into the sewers. The relatively small amount of solid matter is diluted by approximately 100 to 150 gallons of water per person per day. The actual solid discharge per person is about one half pound per day; of that, half is organic matter. These wastes are collected by an intricate net of sewage lines and they are then fed into central treatment facilities.
Primary Treatment. Wastes entering a plant are first screened, and large fragments are ground before being discharged to the flowing sewage for further treatment. In the first stage (primary treatment), sewage flows into concrete basins where the velocity is reduced and the suspended solids removed by gravitational settling. The sewage remains there for up to two hours. Such primary treatment (screening and settling) removes about 50 per cent of the suspended solids, and about 30 per cent of the five day Biochemical Oxygen Demand (BOD).
BOD is a measure of the oxygen required by aerobic organisms to break down or stabilize a given quantity of sewage or other waste. It is important to determine BOD, because the idea is to have the oxygen demand of the organisms take place in the plant to allow them to break up the sewage, rather than pass this demand on to the waters receiving the treated sewage. These waters would otherwise be quickly depleted of their dissolved oxygen thus making those streams uninhabitable by fish and other desirable living beings. If most of the work of these oxygen-dependent organisms can be done in the sewage plant, the effluent that is finally discharged will not tax its receiving waters.
[Figure: Too many streams have become open sewers, a menace to health.]
Secondary Treatment. Secondary treatment involves additional biological treatment of primary wastes to remove still more solids, and further reduce dissolved oxygen depletion in the receiving waters. Wastes are sometimes treated by aerating the waste water to supply oxygen to the micro-organisms causing them to break down the remaining organic matter. The sludges or solids produced in both the primary and the secondary settling stages can be pumped to closed air-tight tanks, called sludge digesters, where solids are stabilized (partially decomposed) by anaerobic biological processes. (In anaerobic biological processes the bacteria do not require oxygen for their life cycle. Large quantities of methane or carbon dioxide gas are produced.) This combination of primary plus secondary treatment reduces the residual biological oxygen demand passed on to the receiving water to about ten per cent of its original value and removes a comparable amount of the suspended solids. Both primary and secondary treatment are widely used in the United States.
Water quality criteria have been developed primarily to assess the amount of sewage wastes in the receiving waters. Among the criteria used for these purposes are: the proportions of dissolved oxygen, a measure of the habitability of the waters for aquatic organisms, and the degree of abundance of micro-organisms in the water tested.
Most commonly the presence of fecal coliform bacteria Escherichia coli (usually abbreviated e. coli.) has been used for this purpose. When present above a specified level of abundance, waters are closed for the commercial production of shellfish. At slightly higher levels, beaches are closed to swimmers. While these bacteria are not known to cause disease, they serve as indicators for the presence of sewage. Other microorganisms in sewage do cause diseases such as cholera; Salmonella sp. causes typhoid and paratyphoid; and Shigella sp. causes dysentery. Viruses, which cause infectious hepatitis, are extremely difficult to detect and study and we know almost nothing about their behavior in the ocean.
Certain constituents are little affected by present treatment techniques, including the compounds of nitrogen and phosphorus that are nutrients. (Nutrients are elements required by plants for their growth.) Techniques now being developed, called tertiary treatment, will remove some of these nutrient elements. The basic chemistry of these sewage treatment processes is relatively well-known, but, in 1970, operating plants were primarily experimental.[1] Consequently, there were no well-proven plants or technology available for widespread adoption. Costs are still an unsettled question. They have been estimated at roughly twice the cost per thousand gallons for combined primary and secondary treatment.
Costs for even the limited treatment afforded by primary and secondary treatment are substantial. In 1954, the capital investment ranged from 12 to 25 dollars per capita. Annual operating costs for a typical municipality were between one and two dollars per capita. Doubtlessly, these prices have increased substantially and further increases in capital and operating expenses can be expected if treatment levels are increased.
Despite substantial success in solving the public health problems with present sewage treatment procedures, there are still aspects of present sewage treatment technology which are not entirely satisfactory. Among these is the disposal of the waste solids (sludges) from the treatment plants. At present, these sludges are put in landfills. In the New York region they are dumped in the coastal ocean, about ten miles offshore from New Jersey and New York. Only about five per cent of the sewage sludges can be used for landfill or soil conditioners in New York City.
Attempts have been made to recycle sewage solids for about 100 years. They have been used for fertilizers and soil conditioners in both Great Britain and the United States, but the results have not been entirely satisfactory. In Britain, the attempt was abandoned. In the United States, the use of sewage solids as a soil fertilizer is possible but uneconomic owing primarily to the high cost of drying and handling the sludges. In general, the solids are low in nitrogen and phosphorus. (Both nutrients typically are discharged with the liquid wastes from the treatment plants.) The dried sludges are also uneven in quality, often unpleasant to use, and frequently contain excessive amounts of various metals, coming from industrial wastes. Most municipalities producing dried sludges for recycling have found that they cannot sell sludge for a price that will meet the production costs, and the income will by no means repay their investment in the plant. New techniques are needed for us to be able to use parts of these wastes.
In much of the world, sewage wastes are collected in a solid form and applied directly to the soil, sometimes after composting in which sewage solids are mixed with other wastes and then aged. In many of these areas the absence of hygienic collection and handling procedures causes a high incidence of diseases of sewage origin such as cholera, typhoid, dysentery, and diarrhea. Although the sewage-associated nutrients are indeed recycled, the public health risks would be unacceptable in this country and especially in urban areas. Furthermore, there is no shortage of manure and other wastes on farms. Commercial fertilizers are replacing manure because they are more convenient.
Although present sewage treatment procedures have been very effective in answering most of the public health needs, they still discharge cysts, bacteria, viruses, and other micro-organisms to the receiving waters. In New York City, this problem is partially solved during summer by adding chlorine to sewage plant effluents. Of course, the chlorine kills many micro-organisms.
Shellfish production is prohibited near waste discharge points. This is because shellfish filter the organisms from the water, and retain them thus concentrated in their gut. Shellfish taken from polluted waters and eaten raw have been implicated as causes of hepatitis and various other diseases. In the United States, a well-established federal-state regulatory mechanism prohibits the commercial taking of shellfish from waters near sewage discharge. While both the rationale and the procedure are relatively simple, they have been quite successful in preventing outbursts of fecal-associated diseases from eating shellfish.
Finally, there is the problem of the nutrients discharged by the sewage treatment plants. Both phosphates and nitrates are discharged in substantial quantities from sewage treatment plants. Phosphates in particular are used in vast quantities in detergents. Since 1935, detergents have caused a two- to three-fold increase in concentration of phosphorus per unit of sewage effluent.
In many water-bodies, phosphorus stimulates the growth of algae, the most important aquatic plants. Algae contain about one per cent phosphorus. Phosphates usually occur in such low concentrations in the water, that its scarcity limits the growth of phytoplankton. Therefore, the discharge of one unit of phosphorus to the water, which already contains the other needed materials and is receiving adequate sunlight, can lead to the growth of 100 units of algae. During photosynthesis, these algae release dissolved oxygen to the surface waters causing high oxygen levels there. This oxygen gradually escapes to the atmosphere.
When these algae grow too fast to be eaten by animals, they sink to the bottom. There they decompose, requiring about 100 units of dissolved oxygen in the process. The oxygen released by these algae during photosynthesis has long since escaped from the water. The result is oxygen depletion in the bottom waters, especially during summer months. High water temperatures limits the amount of dissolved oxygen that the water can hold and increases the rate at which the algae decompose.
Several estuaries show the effects of sewage discharges. Waters in Delaware Bay and New York Harbor have a low concentration of dissolved oxygen, and there are occasions when phytoplankton grow rapidly, when they are known as “blooms.” Blooms of blue-green algae are especially troublesome in the Potomac Estuary. Such blooms are caused by the entry of excess nutrient, primarily from sewage.
Chesapeake Bay, on the other hand, remains in relatively good health. Sewage effluents from Baltimore are used as cooling waters by a large steel plant. Iron added to the water passing through the steel plant precipitates phosphates; the insoluable iron phosphate accumulates in sediments and is thus unavailable to stimulate the growth of algae. It seems probable that this combination of wastes has worked to hold nutrients discharged to the Bay down to acceptable levels.
Another large source of municipal water waste, storm water, should be considered sewage in this discussion of pollution. That is because most cities’ storm water runs off into their central sewage systems. It is perhaps too expensive to build duplicate systems, especially in older communities. Rain water, moreover, collects a great deal of animal waste anyway as it runs through the city streets to the sewers, and it requires sewage treatment. The problems come when a storm overtaxes the ability of the system to handle the extra volume of water dropped by the storm. Then the municipality is forced to bypass sewage treatment plants and release combined sewage and storm runoff into the nearby waterways. Most sewage systems are designed to handle only the dry weather discharge, so that the discharge of untreated sewage is common in most cities.
Dredged Wastes
Navigation channels and slips constitute traps for waterborne solids. Artificially deepened channels and protected areas around the slips provide areas of quiet water where solids settle out, causing the opposite effect to that desired, namely, shoaling. These areas must be dredged periodically to maintain depths adequate for navigation. Although the deposits may not come from the maritime activities using these facilities, they are charged with the cost of removing them. In many instances maritime activities may be hampered by these wastes.
Where do these wastes come from? The answer is not entirely clear. Our information about them is limited, except for their physical properties, which are important in planning and conducting dredging operations. For the past two years, my laboratory has been studying dredged wastes with particular emphasis on those coming from the New York metropolitan region. We find that some of the deposits are sediments carried by the Hudson River, mixed with waste dumped into the river from cities along its shores. Upon reaching the estuary these materials are deposited in the navigation channels. Sewage treatment plants along the harbor are also significant sources of solids. Fine-grained solids and low density materials do not settle out during passage through sewage treatment plants and are therefore discharged to the water. Probably a large fraction of them eventually find their way to the harbor bottom.
In New York Harbor the untreated sewage from a population exceeding two million (primarily on Manhattan), as well as the effluent from numerous industrial plants along the waterfront, is still discharged directly to the harbor.
Sand moved along the beaches of the Long Island and New Jersey coasts also accumulates near the harbor mouth. Approximately 3.5 million tons of wastes must be dredged from New York Harbor each year and disposed of in designated areas on the continental shelf about ten miles from the harbor mouth. Based on the carbon content of these dredged wastes, it seems that perhaps as much as 20 per cent of the total volume may be derived from various waste sources. Some of this carbon comes directly from sewage solids; an unknown fraction is derived from the secondary or indirect affect [sic] of the discharge of nutrients to the water, thus causing increased algal productivity and also adding carbon to the bottom deposits.
Dredging must then be classified as a waste transporting activity. Dredged materials (also known as spoils) must be treated as waste because of the industrial and domestic wastes mixed with them. Dredging activities disturb these old waste deposits and have a noticeable effect on waters near the dredging operation. Part of the effect results from the discharge of fine-grained, low-density solid pollutants during dredging operations. As a result, the carbon content of dredged spoils dumped in disposal areas is often only about half that of the surficial deposits in the area dredged. In the past these dredged wastes were used for landfill operations But the increased demand for waterfront property, and an increased awareness of the need to preserve wetlands for plant and animal life, has eliminated this traditional means of waste disposal in many areas. New methods of handling dredged waste are needed. Dredging has several bad effects in addition to releasing nutrients during dredging, or filling in wetlands. It causes turbidity of the water which inhibits light from passing through; it destroys marine life by the processes of digging, dumping, or poisoning with waste; and it disrupts surrounding organisms.
Industrial Wastes
Industrial activities in the United States contribute an estimated 21.9 billion gallons of wastes each day to the coastal ocean and estuaries. In a few instances, it has been possible to document the effects resulting from these industrial discharges. High levels of DDT in fish taken from California coastal waters have been attributed to the discharge of DDT by a single manufacturing concern near Los Angeles.
In southwestern Kyushu, Japan, a near epidemic of mercury poisoning, locally called Minimata disease, was attributed to the discharge of mercury to coastal waters. In this case, the waste was a methyl mercury chloride which occurred in the wastes from a chemical factory. These materials were discharged to the nearby bay where the mercury was biologically concentrated and passed to man through his eating of fish and shellfish. By the end of 1960, 111 cases of mercury poison had been reported and 41 deaths had occurred through 1965.
Oil spills in coastal waters have been discussed widely. In most coastal areas, small spills during loading and unloading of tankers, or the result of a collision or grounding, are common.[2] It was estimated that, in 1970, about 350 thousand barrels of oil were discharged in U. S. territorial waters. Effects of petroleum spills are well documented. The effects on the ocean bottom are less well-known. It has been suggested that certain refined products are more toxic to bottom dwelling organisms than crude petroleum.
Importance of the Coastal Ocean
Although waste disposal operations in coastal ocean areas are not a worldwide problem, they are ubiquitous and therefore important. The coastal ocean is especially rich in marine life, providing most of the world’s fish production and about ten per cent of its protein. About 90 per cent of the open ocean has only a small amount of nutrients in the sunlit surface layers. This, therefore, limits the growth of the phytoplankton which supply food to support fish production.
The most productive ocean areas are the continental shelves. There the rivers bring nutrients to the ocean. The actions of waves and tidal currents cause a mixing of surface and nutrient-rich subsurface water. The abundance of these nutrients then supports extensive growth of phytoplankton and these in turn feed fish.
The importance of each segment of the coastal ocean to marine life is difficult to specify. We lack knowledge of life cycles for many commercially important fish and their food supply. The importance of the coastal ocean can be seen when one recognizes that about 90 per cent of the commercially important fish depend on the coastal ocean at some critical stage of their life cycle.
Waste disposal in coastal waters has impaired the production of finfish and shellfish. As previously discussed, commercial shellfish production is prohibited in many areas because of the discharge of sewage plant effluents to nearby waters. Shellfish may well be abundant in the waters, but still cannot be produced commercially. In other areas, the low amounts of dissolved oxygen prevent fish from inhabiting these waters or from breeding in them. The destruction of wetlands has eliminated breeding and nursery areas formerly used by the fish. The construction of dams on many rivers has altered the flow characteristics of these rivers and disrupted fish life in them.
Waste disposal operations are not the only biological problem of the coastal ocean. Severe overfishing of productive coastal waters has occurred in many areas. One example is the famous Grand Banks, about 150 miles east of Cape Cod, Massachusetts. This long productive area is now worked over by all of the world’s fishing fleets, and the catch has fallen.
The sum of these various acts of depletion affects the so-called food chain, and so directly impinges on the natural forces that produce and sustain all forms of life. That food chain includes a principal base of phytoplankton in the ocean, which are believed to be the ultimate source of most of the present atmosphere’s oxygen.[3]
The Great Lakes
Up to this point, our attention has been focused on the coastal ocean. Waste disposal operations affecting the coast have also caused substantial changes in lakes, which may serve as well documented models of the effects of uncontrolled waste discharges.
Compared to the coastal ocean, lakes are quite small. To a geologist, they are essentially wide places in rivers on the way to the ocean. The basins in which they occur (in high latitudes) were mostly gouged by glaciers in the past two million years; the U. S.-Canadian Great Lakes are examples of such. A few lakes lie in basins formed by volcanic activity or by large movements of the earth’s crust. Because of their small size and the relatively large volumes of water flowing through them, lakes are ephemeral. They are efficient sediment traps and thus retain river-borne sediment, causing them to fill and eventually to become bogs. Nutrients also tend to be retained in lakes, causing them to change from barren, transparent water (oligotrophic lakes), containing few organisms, to turbid waters, rich in nutrients and phytoplankton (eutrophic lakes). The high productivity of eutrophic lakes uses up the dissolved oxygen when algae decompose. This progression from oligotrophic to eutrophic conditions is part of the natural aging of a lake.
Table 1
Estimated waste production by various sectors in the United States in the late 1960’s.
References
1. Federal Water Pollution Control Administration, The cost of clean water, Vol. 1. U. S. Government Printing Office, Washington, D. C. 1968.
2. Williams, H. R. and C. H. Wadleigh. Agricultural wastes in perspective. Fourth International Water Quality Symposium. San Francisco, August 14, 1968.
3. Wadleigh, C. H. Wastes in relation to agriculture and forestry. U. S. Dept. of Agriculture. Mis. Publ. No. 1065. U. S. Government Printing Office, Washington, D. C. 1968.
| Liquids | Biochemical | Solids | Typical discharge |
|
Waste sources | (109gal/yr) | (106 tons/yr) | (106 tons/yr) | (or waste disposal) points | Reference |
Municipal sewage (120 | 5,300 | 3.3 | 4 | Rivers, lakes, estuaries, | 1 |
Dredged wastes | ? | ? | 380 | Wetland, waterways (off- | 2 |
Manufacturing, all | 13,100 | 10.4 | 8.1 | Rivers, estuaries, | 1 |
(Chemical industries) | (3700) | (4.4) | (0.9) | municipal sewers | 1 |
(Primary metals) | (4300) | (0.02) | (2.1) |
| 1 |
(Paper industries) | (1900) | (2.7) | (1.4) |
| 1 |
(Food industries) | (690) | (1.9) | (3.0) |
| 1 |
Agriculture |
|
|
| Rivers, estuaries, lakes | 3 |
Animal waste | 105,000 | ca.100 | >1000 |
| 3 p. 10, 41 |
Soil erosion |
|
| ca.2000 |
| 3 |
The sequence of lake aging, accelerated by waste discharges, can be seen in the Great Lakes, which are a portion of the drainage basin of the St. Lawrence River. The lakes which best illustrate various levels of pollution are Superior, Michigan, and Erie. Lake Superior, the world’s largest freshwater lake, is quite deep, with an average depth 487 feet, and has little agriculture or industry in surrounding areas. Therefore, it receives relatively little waste discharge and its waters remain clear, and well oxygenated. The invasion of the sea lamprey affected its fish population, but wastes seem to have caused little change.
Navigation channels and slips constitute traps for waterborne solids and must be dredged periodically. Thus, while dredging is not a direct source of waste, it disturbs older waste deposits, releases wastes to inshore waters, and redeposits large volumes of wastes in other areas.
Lake Michigan is smaller and shallower (average depth 276 feet). Its shores are much more densely populated and industrialized than those of Lake Superior. In 1960, the lakeside population was about 5.7 million (excluding Chicago whose municipal sewage does not enter the lake). Because it is a cul de sac, Lake Michigan does not receive much of the flow of unpolluted water from Lake Superior. Those tributaries entering the lake are small and most are polluted.
The lake’s waters remain fairly clear, however, and well supplied with dissolved oxygen at all depths, during all seasons. Organisms are more abundant in Lake Michigan than in Lake Superior, a consequence of greater food production. Also the waters contain more dissolved solids (analogous to salinity in sea water and one measure of waste concentration). In short, water in Lake Michigan is not as clean as in Lake Superior, because of larger waste discharges to the lake, but it is not bad. Though the biological effects so far have been relatively small, they are likely to become more obvious.
Lake Erie, with an average depth of 58 feet, is the shallowest of the Great Lakes but has the largest population along its shores, 10.1 million in 1960. The Canadian shore of the lake is largely agricultural, but the U. S. portion is highly urbanized and industrialized. Because of this, Lake Erie has received large volumes of wastes and shows the greatest deterioration or eutrophication. Total dissolved solid concentrations in Lake Erie are high; phosphates and nitrates are abundant and support large growths of phytoplankton. Decay of these algae on the bottom during periods of calm summer weather deplete bottom waters of their dissolved oxygen, especially in the western portion of the basin.
Table 2
Approximate performance and cost of conventional treatment of
municipal wastes, based on raw waste concentration
| Removal efficiency | ||
|
|
| Primary + |
| Primary | Primary + Secondary1 | Secondary + Tertiary2 |
Biochemical Oxygen | 35% | 90% | >99% |
Chemical Oxygen | 30% | 80% | 95-99% |
Refractory Organic | 20% | 60% | — |
Suspended Solids | 60% | 90% | 99% |
Total Nitrogen | 20% | 50% | 40-60% |
Total Phosphorus | 10% | 30% | 95-99% |
Cost per 1,000 gallons | 3-4 cents | 5-10 cents | 20 cents |
1. Data from L. W. Weinberger, D. G. Stephan, and F. M. Middleton, Solving our water problems—Water renovation and reuse. Annals New York Academy of Sciences 136: Art 5, 131, 1966.
2. Data from A. F. Slechta, G. L. Culp. Water reclamation studies at South Tahoe Public Utility District. Journal Water Pollution Control Federation 39: 787, 1967.
Despite its problems, Lake Erie has produced and continues to produce about 50 million pounds of fish each year, about half of the total Great Lakes fish production. However, there have been profound changes in the species of the fish caught. Many formerly important species such as whitefish, blue pike, and lake trout are no longer caught. Perch, smelt, and other fishes dominated the commercial catches in 1965. The disappearance of desirable fish species has been attributed to decreased oxygen concentrations and changes in the availability of their food supply.
Environmental changes in the Great Lakes can be classified under three categories:
1. Pollution of inshore areas, harbors, and tributaries.
2. Long-term changes in open water far from shore.
3. Long-term changes in sediments.
All the lakes exhibit changes in the coastal sections of the lakes. Usually these are local problems and relatively easy to solve. Changes in the open waters of the lakes need a longer time to replace the water with clean water, and so they are more regional and long-term problems. Perhaps the most serious of all are the slow changes in the deposits accumulating on lake bottoms. Wastes on the bottom continue to use dissolved oxygen, and may also slowly leak wastes back to the overlying water.
Although rarely considered, since they remain out of sight, sediments may pose the most difficult problems of all for programs attempting to restore water quality. We lack the knowledge necessary to rehabilitate large areas covered by sediment and so be able to eliminate their harmful effects on the quality of the water.
Prognosis for the Coastal Ocean and Great Lakes
There seems to be no question that the lakes and coastal ocean around industrialized nations collect a myriad of waste discharges. The problem then becomes, what can be done about it?
I am only moderately optimistic about the prospects for improvement in the next five to ten years. In my opinion, we lack the technology needed to clear up our present waste, and to eliminate the residual effects of past waste discharges. The basic problems are, first, one of definition, and then one of resource allocation. We do not know enough about the components of the biosphere and how they influence each other.
In 1967, it was estimated that approximately 300 billion dollars would be required over the next 30 years to bring air, water, and solid waste disposal operations to the standards established by the states and the federal government. Even ignoring the question of whether the standards are adequate, it seems obvious that we cannot expect this amount of money to be made available in the near future. Congress has already been reluctant to honor existing commitments for the construction of waste treatment facilities and it is unlikely to undertake such massive programs in the near future. Hence, it seems that if we can expect improvements in the waste discharge situation, they will be slow in coming. Most state and local governments lack the initiative and resources to undertake such massive projects.
In some areas, waste disposal should be eliminated to avoid the kind of problems now occurring in Lake Erie. Owing to their small volume and limited capacity to assimilate wastes, discharges to rivers and lakes should be eliminated. This places a heavy burden on agriculture, mining, and inland cities, and it will obviously not be accomplished overnight. It will also require technological advances and massive capital outlays.
Despite its limited capacity, the coastal ocean seems destined to receive a variety of wastes for some time. Part of these wastes originate inland, where other activities have not been able to eliminate waste discharges. Rivers will most likely continue to transport wastes to the coastal ocean. Most of the wastes, however, come from coastal urban centers.
Measuring Wastes
We must learn to manage waste disposal operations in the ocean. The first step is the classification and segregation of wastes. A simple scheme might be based on the volume of the waste involved, its characteristics, and its probable biological effects.
Toxicity would be another aspect to be considered. High toxicity wastes would be those materials which still have toxic effects after a thousand-fold dilution.
Nerve gas is an example of an extremely toxic waste; certain mercury compounds are another example. Low toxicity samples would be those that have no toxic effect after only a ten-fold dilution. An example might be dredged materials. The first step would be to ban waste discharges to the ocean of high toxicity wastes, and especially those high toxicity wastes produced in low volume that could be handled by other procedures.
For the near term, it seems there is little option except to continue ocean disposal of large volume, low toxicity wastes. New waste management strategies need to be devised for these large volume wastes.
Our management methods will require a better choice of sites for disposal operations to protect valuable bottom-dwelling organisms. It might also involve using less objectionable wastes to cover up more objectionable waste deposits. For example, coalash, which seems relatively non-toxic, might be used to cover up sewage-sludge deposits.
Restraining More Dumping
Part of a better waste management philosophy for the coastal ocean would be to prohibit new kinds of waste disposal operations. Many coastal urban areas are short of land available for continued sanitary landfill operations. Several of them have seriously considered disposing of their refuse and garbage at sea, either as compacted bales, or after incineration. Relatively little refuse and garbage, as opposed to treated sewage solids, has been disposed of in coastal waters since the Supreme Court, in the early 1930s, enjoined the City of New York from continuing its refuse disposal operations near the harbor entrance.
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Suggested References
American Chemical Society. 1969. Cleaning Our Environment: The Chemical Basis for Action. Washington, D. C. 249 p. A thorough but relatively elementary presentation of the technical problems involved in air, water, and solid waste problems.
Commission on Marine Science, Engineering, and Resources. 1969. Our Nation and the Sea. Washington, D. C.; U. S. Government Printing Office. Thorough analysis of marine science and engineering, including a discussion of programs in the federal government.
Davies, J. Clarence III. 1970. The Politics of Pollution. New York: Pegasus. 231 p. A discussion of the political, economic, and social aspects of the problems of dealing with pollution problems, especially in the federal government.
Environmental Pollution Panel, President’s Science Advisory Committee. 1965. Restoring the Quality of Our Environment. Washington, D. C.: The White House. 317 p. Discussion of the effects and sources of pollution.
Study of Critical Environmental Problems. 1970. Man’s Impact on the Global Environment: Assessment and Recommendations for Action. Cambridge, Massachusetts: The M.I.T. Press. 319 p. Evaluation of global environmental problems.
U. S. Department of Health, Education, and Welfare. 1969. Toward a Social Report. Washington, D. C.: U. S. Government Printing Office. 101 p. An attempt to state the major social, economic, health, and pollution problems facing our society and some estimate of costs associated with each.
U. S. Department of the Interior, Federal Water Pollution Control Administration. 1968. Lake Erie Report. Great Lakes Region. 107 p. A comprehensive statement of the environmental condition of Lake Erie, the causes of present water quality, and an action program for the lake.
U. S. Department of the Interior, Fish and Wildlife Service. 1970. National Estuarine Study. Washington, D. C.: U. S. Government Printing Office. 7 volumes. Comprehensive study of environmental conditions in U. S. coastal waters and Great Lakes.
Scientific American, September 1970. pp. 44-194, “The Biosphere.”
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New Technology
New technology is clearly needed. For example, the development of acceptable means of solid waste incineration would permit substantial reductions in the volume of wastes going to landfills. Among the improvements needed are more reliable, less expensive incinerators, which must emit fewer particles and gases. Perhaps incinerators could also be developed which would handle sewage sludges as well as solid wastes. Alternatively, compactors may be found to be useful in many applications.
Finally, it may be necessary to develop more direct means of water quality management. Direct removal from our waters of those aquatic plants that are stimulated by discharges of nitrate and phosphate would prevent the plants from decaying, and so from releasing these nutrients back to the water. The removal of such plants as water hyacinths and water chestnuts would permit navigation. Another way of eliminating such plants might be to encourage organisms to graze on these plants and on algae, and then to harvest the fish that eat the organisms. This would remove phosphates and nitrates from the water.
Assuming that we will need to dredge certain waterways along the coast, there are several measures that can be taken to mitigate the ill effects of the operation, turning these techniques of dredging into tools of environmental management. The removal of waste deposits by dredging might be an attractive option in certain areas. Many of the wastes in the harbors are essentially sewage sludges, and their removal may improve the quality of harbor water. If this dredging is done in summer, the result might be the undesired release of both nutrients and oxygen-demanding substances into the water. But, if dredging were done in winter months, when plant productivity is low, and dissolved oxygen concentrations are high, the measure might well lessen the impact of dredging on the waters affected by such operations.
Summary
1. The U. S. coastal ocean and the Great Lakes now receive large waste discharges coming primarily from urban areas.
2. Coastal ocean circulation tends to retain these wastes near the coast, inhibiting their mixing with, and their dilution by, the adjacent open ocean waters.
3. The resulting deterioration in water quality interferes with various uses of coastal waters—among these are impaired recreation and food production. These effects are commonly called pollution.
4. Sewage and industrial wastes are major contributors to the pollution of harbors and estuaries. Pollutants from farm and mine are not thought to be as significant as the foregoing because they have more effect locally, when carried by water run-off, and do not pollute coastal waters directly with the same impact as sewage or industrial waste.
5. Dredging, while not a direct source of waste, disturbs older waste deposits, releases wastes to inshore waters, and redeposits large volumes of wastes in other areas. Many of the disposal areas receiving dredged wastes are not themselves affected by other waste sources.
6. Wastes to be dumped in the coastal ocean should be classified and segregated based on the volumes involved and their probable biological affects [sic].
7. New waste management schemes are needed. Among these schemes will be the elimination of low volume, high toxicity wastes from ocean dumping. An example would be a prohibition on the disposal in the ocean of nerve gas and similar substances. Large volume, low toxicity wastes might be used for the rehabilitation of areas covered by more objectionable deposits.
The cost of waste disposal, sufficiently satisfactory to the community around the industry, and to the needs of the balance of people and the resources of nature, must become a regular part of an industry’s planning. This is also the case with municipalities with regard to disposing of their sewage. If they do this, both major contributing sources of coastal water pollution will be able to see their part in environmental deterioration and simultaneously gain a tool with which they can help reduce that part.
Discharging waste into water is part of what happens when man brings about change in the form and relationship of matter and energy. If we can learn how to dispose of waste by turning it into a form more useful to man, and less harmful to our environment, we may find that man has finally mastered the basic cycle required to sustain a sophisticated and populous community.
[signed] M. Grant Gross
[1] Methods other than chemical treatment include a small commercial plant using a gamma radiation process that has been successfully operated at Fish-eating Creek Plant, Florida. (The plant appears to provide one solution to sewage treatment, killing virtually all bacteria, and reducing by up to 33 per cent the phosphates and other nutrients in the sewage.) Conventional or non-nuclear methods, including ozonation and the use of microwaves, produce effluents clean enough to be usable as drinking water.
[2] The Maritime Administration in 1970 circulated to private enterprise a request for proposals for a study of deep draft offshore terminals that would include several characteristics in their design which could reduce the pollution of coastal waters. The studies should examine ideas such as using solid waste for fill, eliminating thermal pollution of bays and estuaries by including a nuclear plant on the offshore terminal, and reducing oil spills by making it unnecessary for tankers to navigate hazardous inshore waterways.
[3] See page 17, Marine Science Affairs, Annual Report of the President to the Congress on Marine Resources and Engineering Development, April 1970, U. S. Government Printing Office.