Marine Chemistry in the Coastal Environment - ACS Publications

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Trends in Waste Solid Disposal in U.S. Coastal Waters, 1968-1974 M. G R A N T GROSS Chesapeake Bay Institute, The Johns Hopkins University, Baltimore, Md. 21218

Sources of Waste S o l i d s Large volumes of s o l i d s are transported to sea by barges or seagoing hopper dredges f o r d i s p o s a l i n c o a s t a l waters. These wastes ( l i s t e d i n approximate order of volumes dumped at sea) i n clude sediment d e p o s i t s dredged from waterways, s o l i d s i n waste chemicals, sewage sludges, rubble from b u i l d i n g c o n s t r u c t i o n and d e m o l i t i o n , and f l y ash (1,2). F l o a t a b l e waste s o l i d s such as garbage, r e f u s e , and r u b b i s h as w e l l as e x p l o s i v e s are excluded. Although produced i n l a r g e q u a n t i t i e s i n urban areas, these materi a l s are not now dumped i n c o a s t a l or e s t u a r i n e waters, except from ships ( 3 ) . Riverborne sediments c a r r i e d i n t o harbors by e s t u a r i n e c i r c u l a t i o n i n the adjacent c o a s t a l ocean and by sands moving along beaches (4) must be dredged from harbors. A r t i f i c i a l l y deepened n a v i g a t i o n channels and i r r e g u l a r s h o r e l i n e s formed by s l i p s and basins used f o r s h i p p i n g are e f f e c t i v e sediment t r a p s and must p e r i o d i c a l l y be dredged to m a i n t a i n water depths needed f o r n a v i gation. I f c l e a n g r a v e l s , sands, or coarse s i l t s were the only mater i a l s dredged, there would be l i t t l e problem i n most c o a s t a l urban areas. Dredged m a t e r i a l s have been used f o r l a n d f i l l , e s p e c i a l l y h y d r a u l i c l a n d f i l l s , and f o r other c o n s t r u c t i o n purposes. In u r ban areas, however, dredged m a t e r i a l s must commonly be handled as wastes because the n a t u r a l r i v e r b o r n e sediments have been p o l l u t e d by municipal and i n d u s t r i a l wastes. Moreover, convenient l a n d f i l l s i t e s are u s u a l l y u n a v a i l a b l e at the time when wastes must be disposed o f . In both cases, ocean d i s p o s a l i s an a t t r a c t i v e option. M u n i c i p a l wastes, i n c l u d i n g sewage s o l i d s , are major c o n t r i b utors of m a t e r i a l s dredged from n a v i g a b l e waterways. Untreated ("raw") sewage i s o f t e n discharged to the waterways, which then provide primary treatment through g r a v i t a t i o n a l s e t t l i n g of s o l i d s and secondary treatment through b i o l o g i c a l degradation of organic matter. The s o l i d s s e t t l e out i n the waterways. E f f l u e n t s from 394

Church; Marine Chemistry in the Coastal Environment ACS Symposium Series; American Chemical Society: Washington, DC, 1975.

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GROSS

Waste Solid Disposal

395

sewage treatment plants also carry suspended solids into adjacent waterways, and some of these solids doubtlessly add to the deposi t s that must be removed by dredging. In addition to the human wastes, many urban areas also discharge wastes and debris washed from streets by storm water discharges.


Regulation of Ocean Disposal In the united States, prior to 1973, regulation of dredging and disposal of dredged materials was primarily the responsibility of the U.S. Army Corps of Engineers. In most areas, these regulatory functions were conducted under the authority of the Refuse Acts (.5), which prohibited waste disposal i n navigable waters without prior permission of the local Corps of Engineers D i s t r i c t . In New York, Baltimore, and Hampton Roads, Virginia, dredge spoil disposal was regulated under provision of the Supervisor of Harbor Act (6). On the Pacific coast, especially i n California, regional and state agencies were also involved i n regulation of waste d i s charges (1). Since A p r i l 1973 waste disposal i n U.S. coastal waters has been regulated through the issuance of permits by the Environment a l Protection Agency (EPA), except for dredged "spoils," under provisions of PL 92-532, The Marine Protection, Research and Sanctuaries Act of 1972. Dredge spoil disposal i s conducted under permits issued by the Corps of Engineers, subject to EPA review. This regulatory program i s directed toward a "no harmful discharge" goal and covers a l l dumping seaward of the baseline from which the t e r r i t o r i a l sea i s measured (7). Waste Disposal Sites Most waste disposal sites are situated i n open estuarine waters or on the continental shelf, relatively close to city or i n dustry generating the wastes. Disposal sites are usually deeper than 20 meters i n the United States except where the materials are used for beach replenishment or construction of a r t i f i c i a l fishing reefs. (In the Gulf of Mexico some sites are located i n waters as shallow as 4 meters.) Beneficial uses of waste solids appear to be the exception rather than the rule. In order to avoid interference with navigation and to remove disposal sites as far as possible from beaches and other public areas, many are located more than 5 kilometers from the nearest land, often i n international waters. Of thirty-one sites along the open Atlantic coast from Maine to Cape Hatteras, North Carol i n a , for which good location data were available i n 1970, seventeen were more than 5 kilometers from the coast and eight were more than 10 kilometers from the coastline. A site used for toxic chemicals i s approximately 190 kilometers from the entrance to New York harbor. Estuarine areas have i n the past received large volumes of


MARINE


396

CHEMISTRY

waste solids. Chesapeake Bay, Long Island Sound, and Puget Sound each have several waste disposal sites (Table 1). A l l were used primarily for disposal of locally dredged wastes except for Long Island Sound, which has received wastes from the New York Metropolitan Region as well as small volumes of waste chemicals dumped in the eastern end. In general, more recently established waste disposal areas are farther offshore than older disposal areas and this trend continues . And use of estuarine disposal sites seems l i k e l y to d i minish further, owing to local opposition from fishing, s h e l l f i s h ing, and conservation interests. In the late 1960s, there were at least 140 waste disposal sites i n U.S. estuarine and coastal ocean waters (Table 1). Along the U.S. Atlantic coast, there were fifty-nine active waste disposal sites (Figures 1 and 2). Puerto Rico had two active sites. At least twenty sites were actively used along the Gulf of Mexico coast, and at least sixty sites were i n use along the U.S. Pacific coast, including Alaska. No data were available on waste disposal operations i n the Hawaiian Islands or U.S. territories or possessions . Although this report does not include the Great Lakes, ninety-five waste disposal sites were reported to be active there in the late 1960s (8). Despite the limitations of the data, i t i s apparent that the number of actively used disposal sites i n U.S. waters has dropped from 140+ i n the late 1960s to 110 i n 1973 (7). Many of the i n shore and estuarine sites have been abandoned or are scheduled to be moved because they are too close to shore or interfere with commercial fishing operations. Natural Sediment Sources Except for the Gulf Coast, most continental shelf areas now receive l i t t l e sediment (9) which might dilute or bury waste deposits. Therefore, i t i s essential to consider the tonnage of sediment brought by rivers to each of the coastal areas i n comparison with the tonnage of wastes deposited there. This permits a crude assessment of potential environmental effects resulting from waste deposits remaining i n contact with overlying waters or with bot torn-dwelling organisms for long periods of time. Waste discharges i n the Canadian Maritime Provinces, the U.S. portion of the Gulf of Maine, Long Island Sound, and the midAtlantic coast areas greatly exceed the probable suspended sediment discharge by rivers in these areas (10). For example, the discharge of riverborne suspended sediment into Long Island Sound is probably about 10 metric tons per year, whereas waste d i s charges prior to 1970, exceeded 10 metric tons per year (11). Furthermore, the sediment comes primarily from the Connecticut River near the eastern end of the Sound. Waste disposal a c t i v i ties were concentrated i n western Long Island Sound because the bulk of the wastes came from nearby densely populated urban areas. 5


22.

GROSS


397

Table I. Location and number of waste disposal sites i n various coastal ocean areas with estimated tonnages of wastes dumped i n each region, 1960s.


Disposal Sites (no. of active sites)

Estimated Tonnage (10 tons/year) 6

Atlantic Coast (61) Gulf of Maine (13) Mid-Atlantic coast (29)* South Atlantic (17) Puerto Rico (2)

14.3

Gulf of Mexico (20+) Eastern Gulf (9) Western Gulf (5+) Mississippi River (6) Pacific Coast (59) California (3) Oregon-Washington (38) Total

10 56.2

* Includes Long Island Sound (12) and Chesapeake Bay (2)(after 11)



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Figure 1. Location of waste disposal sites and volumes of dredged wastes (10 m /year) discharged in 1968 6

Figure 2. Locations of waste disposal sites in the New York Metropolitan Region in 1968 and volumes of dredged wastes (10 m / year) discharged in each s


5

3

22.

GROSS

399


Near the mouth of the Mississippi River the river's suspended sediment load (12), about 3.1 * 10 metric tons per year, greatly exceeds the tonnage of wastes dumped there so that wastes are l i k e l y to be buried rather quickly. Similar situations probably prevail near the mouths of other rivers i n the Gulf of Mexico, near the mouth of the Columbia River (13) and i n the Strait of Georgia (14). Elsewhere on the continental shelf, wastes probably accumulate and remain at the water-sediment interface for long periods of time. Based on these rather sketchy data, one can surmise that large volumes of wastes dumped at sea are l i k e l y to have the least effect i n the Gulf of Mexico, and greatest effect on the Atlantic Coast.


8

Impact of Dredged Waste Disposal Waste solids pose immediate and potential long-term problems in the coastal ocean. The immediate effects arise i n two ways— from dredging and from waste disposal operations. Wastes and sediments are disturbed during dredging causing increased turbidity and releasing nitrogen compounds, phosphates, and various reduced substances to the water. Increased oxygen demand arising from i n troduction of reduced substances (15) and decomposition of excessive phytoplankton growth (resulting from the phosphate and n i trate enrichment of the waters) deplete dissolved oxygen concentrations i n near-bottom waters (16). Potentially more troublesome i s the long-term exposure of unburied waste deposits on the continental shelf or estuary bottom. Since most waste disposal sites are located i n relatively shallow water, t i d a l currents and wave action may resuspend and move them outside the designated disposal area. Under certain conditions such as upwelling, movement of near-bottom waters i s directed landward, toward the estuary or river mouth. Some resuspended wastes may move toward beaches or back into the harbor from which they were removed. There i s no compelling evidence that large volumes of waste solids have moved from disposal sites to be deposited on beaches. Studies of two waste disposal sites near New York City receiving dredged wastes and sewage sludges indicate that populations of bottom-dwelling organisms i n both waste disposal areas were severely reduced over several tens of square kilometers (16). Factors thought to be responsible include low dissolved oxygen concentrations, i n waters over the disposal s i t e and presence of toxic compounds, or pathogenic organisms i n the wastes. In addition, i t seems l i k e l y that physical factors may also play a role. The bottom was originally hard sand or gravel, but the waste deposits formed a fine-grained soft bottom. Furthermore, rapid accumulation of wastes (ranging from 0.4 to 30 cm/year, assuming that the wastes are spread uniformly throughout the affected areas) may make i t impossible for many bottom-dwelling organisms



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CHEMISTRY

to l i v e i n waste disposal sites (17). And the changed bottom conditions inhibit (or prevent) repopulation of the disposal sites by organisms from nearby unaffected ocean areas. Since 1968, data have become available on the environmental impact of waste solid disposal i n coastal waters ; much of the data come from studies of the New York Bight (18). Enrichments of several metals (including Cu, Pb, Ni$ Zn, and Cr) were substantial, typically 10 to 25 times greater than i n nearby uncontaminated sediment deposits (19). These metal-rich sediments were found nearly 40 km down the axis of Hudson Channel seaward of the designated disposal sites. Studies of the effects of sewage sludge disposal i n the Thames Estuary (20), the Firth of Clyde (21), and Liverpool Bay (22) have not found, i n general, the obvious local effects on bottom-dwelling organisms that were observed i n the New York Bight disposal sites. This may be due, i n part, to better dispersal of the sludge i n the coastal waters around Great Britain because of strong t i d a l currents there. In this case, the effects of waste disposal operations may eventually be f e l t over a much wider area. Trends i n Ocean Disposal Operations Despite changes i n regulation of disposal operations, coastal ocean areas w i l l probably receive even larger volumes of wastes over the next five to ten years. Coastal urban areas are short of land necessary for the present style of waste disposal operations (23) ; they find ocean disposal to be an attractive solution for existing and foreseeable waste disposal problems. At present there i s no equal-cost alternative to ocean disposal for largevolume wastes. Hence, there w i l l l i k e l y be increasing pressure for new types of wastes to be dumped in ocean waters, at least on an interim basis. It i s useful to consider changes i n tonnages of wastes disposed at sea i n 1968 and 1973 (Table 2). The amounts of indust r i a l wastes, sewage sludges, and construction-demolition debris have increased, at compound rates of +2.9, +3.9 and +14.2% per year, respectively. Ocean discharges of garbage and refuse have been greatly reduced and disposal of explosives at sea has ceased. Tonnages of dredged spoils disposed at sea have apparently decreased from an estimated 62 million tons i n 1968 to 37 million tons i n 1973. (Table 2.) This apparent decrease may well be the result of incomplete data. It i s also instructive to consider trends i n ocean disposal since 1949 (Table 3). These data indicate a compound annual change of +7.7% between 1949 and 1968 i n the amount of waste disposed at sea. (Data i n Tables 2 and 3 are not directly comparable, although each indicate trends in the two periods involved.) It i s too early to judge the impact of the new regulatory procedures, implemented i n 1973, and the use of the ocean for disposal of i n dustrial and municipal wastes. There has, however, been a de-



1

+14.2 + 4.2 - 6.9 - 4.7

1.16 12.0 36.9 48.9

0.57 9.74 52.2 61.9

0 0 9.45 9.45

0 0.98 8.32 9.30

0 1.41 9.01

0 0.70 13.0 13.7

1.16

10.6

18.4

29.0

0.57

8.06

30.9

39.0

Construction and demolition debris

Subtotal

«•

3

2

To calculate tonnages of dredged wastes, a solid content (dry) of 0.9 metric ton per cubic meter of dredged material i s assumed.

Compound increase.

1973 data from (7).

1968 data from (2).

TOTAL

10.4

+ 3.9

5.43

4.48

0

0

0

0

5.43

4.48

Sewage sludges

11

+ 2.9

5.41

4.69

0

0.98

1.41

0.70

4.00

3.01

Industrial wastes

Dredged wastes

(%)

1973

1968

1973

1968

3

Change/year

1973

Total

(in millions of tons).

Pacific Ocean

2

1968

Gulf of Mexico

and 1973

1973

Atlantic Ocean

Ocean disposal of various waste solids, 1968

1968

Waste type

Table II.


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Table I I I .

CHEMISTRY

Ocean waste d i s p o s a l , excluding dredged s p o i l , 194968, i n m i l l i o n s of short tons (2).

Coastal region

1949-53

1954-58

1959-63

Atlantic

8.0

16.0

27.3

Gulf

0.04

0.28

0.86

2.

Pacific

0.49

0.85

0.94

3. 4

Total U.S.

8.53

9.13

Average/yr

1.7

1.8

1964- 68

31. 1 6

29.1

37. 1

5.8

7. 4

These data i n c l u d e the tonnage of l i q u i d s discharged as w e l l as waste s o l i d s . They cannot be compared d i r e c t l y w i t h Table 2.



22.

GROSS

403


crease i n dredge spoil disposal in the past five years. It seems most l i k e l y that there w i l l be increasing volumes of dredged wastes i n the future as new port f a c i l i t i e s are prepared for deep-draft vessels, requiring 20 to 25 m of water. In the U.S., channel depths now rarely exceed 15 m; thus extensive dredging w i l l l i k e l y be required to accommodate larger ships. The magnitude of this potential problem can be appreciated by considering that the dredging necessary for maintaining depths exceeding 20 m at the entrances to the Hook of Holland (Rotterdam-Euro port, Netherlands) resulted i n the annual dredged-waste discharges i n creasing from 5.1 x 10 m i n 1957 to 2.2 x 10 m i n 1968, a fortyfold increase i n eleven years, an amount 3.9 times that dredged from New York Harbor i n 1964-68 (18). These figures refer mainly to maintenance dredging. At present the amount of dredged mater i a l i s substantially increased because of the deepening of the entrance channel for passage of deep-draft tankers. A comparable increase in dredged waste disposal was experienced at the port of Amsterdam during this same period (Director, Rijkswaterstaat, written communication, January 2, 1970). The total volume of mat e r i a l dredged from these ports was 1.3 x 10 m , about one-third the present annual sediment discharge of the Mississippi River (12). If comparable port developments occur i n Nortil America, the volume of dredged materials w i l l probably increase sharply. Because of the widespread use of ocean disposal sites, their potential long-term effects, and the present inadequate knowledge about the wastes and their effects on the ocean waters and marine organisms, marine scientists face a challenge to apply their research capabilities i n this area. There i s also a chance to contribute toward possible solutions for environmental problems as well as to learn more about coastal ocean processes that are otherwise d i f f i c u l t or impossible to study. Far more studies with more careful experimental design w i l l be needed to determine what i s causing the environmental degradation observed i n the New York Bight and to devise means of dealing with i t . Present studies of such sites can best be described as inclusive rather than discriminating. Virtually every conceivable item i s measured or examined. At best this i s costly and i s l i k e ly to be self-defeating. The recent abandonment of disposal sites raises the issue of rehabilitation of waste deposits. On land, a garbage dump i s closed by covering i t with several feet of earth and landscaping. But for ocean areas we lack even this simple technology. It seems reasonable to expect that a complete ocean waste management program would include efforts to isolate waste deposits i n abandoned sites from possible interactions with the overlying water column or marine l i f e . This i s probably a simple problem but one that merits attention. Another trend to be considered i s the probable increased volume of sewage sludges as the required level of treatment i s raised. And the use of scrubbers to remove S O 2 from power plant 5

3

7

8

3

3


404

MARINE CHEMISTRY


exhausts w i l l also generate large volumes of fine-grained watery wastes which are d i f f i c u l t to dispose of on land, especially i n urban areas. For coastal c i t i e s and industries, ocean disposal i s a convenient and, by conventional economic analysis, a relatively cheap disposal method. Such disposal operations ( i f permitted) pose new challenges to marine scientists to provide the data and insights on the coastal ocean and i t s organisms needed for proper planning and monitoring of the disposal operations. Abstract Estuaries and coastal oceans receive large volumes of waste solids dredged from harbors or removed from sewage treatment plants or industrial plants and placed on the adjacent continental shelf, which often receives little sediment derived from other sources. Legislation, implemented i n 1973, has caused a s i g n i f i cant reduction i n the number of sites used; from 140+ i n the late 1960s to 110 i n 1973. Dredged spoil disposal apparently decreased; from 56 million tons i n 1968 to 37 million tons i n 1973. Dumping of industrial wastes, sewage sludges and construction debris has increased at annual rates of +2.9%, +3.9% and +14.2%. The present trend is to operate fewer disposal sites located f a r ther from shore. Literature Cited 1. Brown, R . P . , and Smith, D.D. Marine Pollution Bulletin (1969) 18:12-16. 2. Smith, D.D. and Brown, R.P. "Ocean disposal of barge-delivered liquid and solid wastes from U.S. coastal c i t i e s , " Environmental Protection Agency Publication SW-19c, Washington, D.C. (1971). 3. Cox, G.V. Environmental Science and Technology (1975) 9(2): 108-111. 4. Meade, R.H. Journal of Sedimentary Petrology (1969) 39(1); 222-234. 5. U.S. Congress, 1899. River and Harbor Act, approved March 3 1899 (30 Stat. 1152; 33 U.S.C. 407); River and Harbor Act, approved March 3, 1905 (33 Stat. 1147; 33 U.S.C. 419). 6. U.S. Congress, 1888. Supervisor of Harbor Act, approved June 29, 1888 (33 U.S.C. 441-451), amended July 12, 1952 and August 28, 1958 (Pub. L . 85-802, 72 Stat. 970). 7. EPA. Administration of the ocean dumping permit program: Second Annual Report, Environmental Protection Agency, Washington, D.C. (1974). 8. U.S. Army Corps of Engineers. "Dredging and Water Quality Problems i n the Great Lakes," Buffalo, New York (1969). 9. Emery, K.O. Bulletin of the American Association of Petroleum Geologists (1968) 52:445-464.



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10. Dole, R.B. and Stabler, H. U.S. Geological Survey of Water Supply Paper (1909) 234:85. 11. Gross, M.G. Waste-solid disposal in coastal waters of North America, p. 252-260. In W.H. Matthews and others (ed). Man's Impact on Terrestrial and Oceanic Ecosystems. M.I.T. Press, Cambridge, Mass. (1971). 12. Holeman, John N. Water Resources Research (1968) 4(4):737747. 13. Gross, M.G., McManus, D.A. and Ling, Y-Y. Journal of Sedimentary Petrology (1967) 37(3):790-795. 14. Waldichuk, M.W. Fisheries Research Board of Canada, Progress Report (1953) No. 95:59-63. 15. Brown, C.L. and Clark, R. Water Resources Research (1968) 4(6):1381-1384. 16. Pearce, J.B. The effects of solid waste disposal on benthic communities in the New York Bight, p. 404-411. In M. Ruivo (ed). Marine pollution and sea life. Fishing News (Books) Ltd., London (1972). 17. Gross, M.G. Water Resources Research (1970) 6(3):927-931. 18. Gross, M.G. Geological Society America Bulletin (1972) 83:3163-3176. 19. Carmody, D.J., Pearce, J.B. and Yasso, W.E. Marine Pollution Bulletin (1973) 4(9):132-135. 20. Shelton, R.G.J. Marine Pollution Bulletin (1971) 2:24-27. 21. MacKay, D.W., Halcrow, W. and Thorton, I. Marine Pollution Bulletin (1972) 3(1):7-11. 22. Dept. of the Environment. "Out of Sight, Out of Mind: Reof a Working Party on the Disposal of Sludge in Liverpool Bay", Her Majesty's Stationery Office, London, 3 volumes (1972). 23. Regional Plan Association. Waste management, Regional Plan Association Bulletin, 107 (1968).


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