yd'/ year). Proposed new channels and enlargements would generate about 

 197,600,000 nr (260,000,000 yd 1 ), including about 76,000.000 nr (100,000,000 yd') 

 for the authorized completion of a 15 m (50 ft) channel from Baltimore to the 

 Atlantic Ocean (McGarry. 1976; Villa et al., 1977). Although dredging can release 

 suspended sediments and sometimes associated chemicals, the greatest associated 

 problems are related to placement of the dredged materials. On-land sites are 

 expensive and limited. The states of Virginia and Maryland as well as federal 

 agencies object strenuously to wetland placement. Overboard placement is only 

 conservatively permitted — and only for relatively clean materials, not defined as 

 contaminated. And theseasonand dredgingtechniquesare controlled. In Maryland, 

 it is specifically illegal to place any of the sediments from Baltimore Harbor, 

 containing large quantities of many pollutants as the result of centuries of casual use, 

 overboard in the waters of Chesapeake Bay (Tsai etal., 1979). Long and acrimonious 

 arguments have followed a proposal to create a large diked containment structure at 

 Hart and Miller Islands to receive about 39,520.000 m 3 (52,000,000 yd'), of 

 contaminated sediments and the project has not yet received full approval. 

 Proposals to place contaminated sediments on old spoil sites and dewater them to 

 produce useful land have not been enthusiastically received. Special concern has 

 been expressed over the chemical characteristics of the water released. Meanwhile, 

 Virginia has utilized a large diked area at Craney Island in the James River, but the 

 capacity of that facility may soon be saturated (Villa et al., 1977). 



Potential pollution from the dredging and placement of sediments has therefore 

 become a principal issue in the Chesapeake Bay region, as in all coastal areas where 

 major shipping occurs. This has been ranked as a major regional issue for the North 

 and Mid-Atlantic regions (Horn et al., 1980). The input of sediment continues, but 

 adequate accepted long-term solutions have not yet been found. 



Sediments have, however, a different important relation to pollution in the Chesa- 

 peake Bay and other estuaries in that they are frequently associated, physically or 

 chemically, with chemical materials introduced to or present in the estuary. 

 Nutrients, heavy metals, pesticides, and many other inorganic and organic elements 

 and compounds sorb to or chemically react with sedimentary particles. The source, 

 routes, rates, and effects of these materials are largely determined by the related 

 processes for the sediments. 



The general components and processes for some sediment-related chemical 

 materials are known for the Chesapeake Bay system, but new investigations are 

 underway in the Chesapeake Bay Program (Office of Research and Develop- 

 ment EPA, 1980). These include intensive studies of the processes of nutrient 

 deposition; nutrient modification in and release from sediments; research on the dis- 

 tribution, physical properties, budgets, and rates of sediments and sedimentation; 

 research on the transport, fate, and transformation of metals related to suspended 

 and deposited sediments; development of improved techniques for extraction and 

 analysis of organic compounds in sediments and tissues; studies of the chemistry of 

 pore waters; and examination of the relationships among sediments, associated 

 chemicals, and the organisms living in the sediments. Only preliminary reports are 

 presently available from these system-wide studies. They should make enormous 

 contributions to the understanding of sediments and pollutants in the Chesapeake. 



Flow Alteration 



Modification of the flow into an estuary has not traditionally been considered as 

 possible pollution, but it falls under a somewhat extended interpretation of intro- 

 duction of deleterious conditions as the result of human activity. The many impor- 

 tant influences of freshwater input upon estuaries were recently reviewed in an exten- 

 sive literature summary (Snedaker et al., 1977) and were the subject of a major 

 symposium (Coastal Ecosystem Project, 1980). Both demonstrate that substantial 

 changes in the quantity or pattern of input can have enormous effects on the 

 physical, chemical, and biological content and processes of an estuary — and there- 

 fore upon the human uses of it. 



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