combined with solids, in contrast to the inefficient removal of metals in 

 solution. Brannon et al . (1978), Chen et al . (1978), and Hoeppel et al . 

 (1978) provide more detailed discussions on this subject. 



. Within a confinement area, the uptake of contaminants through the food 

 chain, as by feeding waterfowl, is a distinct possibility, but definitive 

 studies are not available. Possible routes of uptake are through ingestion of 

 either above- or below-ground portions of plants, or through ingestion of soil 

 or aquatic invertebrates. Chemicals with higher partition coefficients will 

 concentrate in the organic fractions and ultimately become associated with 

 food chain organisms. Those chemicals of major concern include PCBs and poly- 

 nuclear aromatic hydrocarbons that have been found at biologically significant 

 levels in fish and wildlife (Koeman et al . 1973). 



Potential pollution from confinement areas is not limited to the period 

 of active dredging. Placing anaerobic sediments in a nonwetland containment 

 area will enhance release of heavy metals through the process of metal sulfide 

 oxidation and an increase in acidity. During a subsequent storm, heavy metals 

 may be released over the weir in significant quantities. Heavy metals may be- 

 come more available to the environment when placed in a terrestrial disposal 

 area than when deposited in an aquatic environment where they may remain in an 

 anerobic state (Khalid et al . 1977). According to Gambrell et al . (1978), cer- 

 tain types of dredged material may become moderately to strongly acidic upon 

 drainage and, under non wetland conditions, the subsequent oxidation presents 

 a high potential for contaminant mobilization. 



Island, Fastland, or Beach Disposal 



Dredged material is often used to construct fasti ands (high and dry lands 

 that are formed over a relatively short period of time, including islands) 

 in existing shallow waters or wetlands as sites for industry or recreation 

 (Gushue and Kreutziger 1977). Impacts associated with these disposal areas 

 include: (a) the permanent loss of wetlands or water bottoms; (b) changes in 

 water circulation patterns and flushing rates; and (c) secondary impacts from 

 industrialization such as increased surface runoff, and point and nonpoint 

 source pollution. 



Beach nourishment projects are becoming more common and often are an 

 alternative for the disposal of sandy material . The greatest adverse impacts 

 associated with beach nourishment appear to be turbidity at the time of dis- 

 posal and for several months thereafter as the fine-grained material is worked 

 from the sand and transported down current. Smothering of benthic organisms 

 appears to be a minor short-term impact. 



Wetland Disposal 



Disposal of dredged material in wetlands is now less frequent due to recent 

 recognition of the value of wetlands. Often, however, the only economically 

 viable choices are: (1) depositing dredged material in a confined disposal 

 area that is constructed within the confines of the wetlands or (2) spreading 

 the material thinly over a large section of the wetland. Is it better to 

 "write off" a small parcel of wetland habitat for wildlife use, to protect the 

 rest of the wetland, or can all of the wetlands be retained by spreading the 



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