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ground and the mixing process within the disposal site water column mitigated any 
effect. 
The major impact, and usually the only impact found at aquatic dredged material 
disposal sites, was the physical mounding of the material. Benthic recolonization of 
the mounds was found to be relatively rapid on fine grained sediments and some- 
what slower on coarse grained material. 
“Bulk” or total sediment analysis or inventory does not relate to any mobile or 
biologically available chemical fraction of a sediment, nor can it predict or evaluate 
potential environmental consequences. 
Petroleum and chlorinated hydrocarbon uptake studies suggest minimal uptake 
by organisms from the solid phase of sediments with no apparent movement of con- 
taminants out of the dump site. 
Land-based alternatives can be considered more environmentally and sociologi- 
cally complex than water-based alternatives. Further, in regard to the disposal of 
contaminated sediments, land-based alternatives appear to offer limited additional 
protection in relation to human health impacts, as compared to ocean disposal. 
Section 103 of MPRSA, as well as Section 404 of the CWA require the Corps to 
assess long-term effects of dredged material disposal from Federal and non-Federal 
projects. However, due to the relatively short time frame of the DMRP, all questions 
related to long-term effects of dredged material disposal were not addressed. A\I- 
though the Corps and EPA have developed first generation predictive procedures to 
evaluate long-term effects, differences in interpretation of these procedures between 
regulatory agencies continue. 
Since the completion of the DMRP, the Corps has continued to conduct low level 
monitoring at several field sites which were established under the DMRP. However, 
beginning this fiscal year, we have formally established a new R&D effort specifi- 
cally to evaluate the potential long-term effects of our disposal operations. 
The basic objectives of this effort, entitled the Long-Term Effects of Dredging Op- 
erations, or LEDO Program are to provide new or improved technology to predict 
long-term (including cumulative) environmental impacts of dredging operations and 
to address methods of minimizing any adverse impacts. Specific areas of research 
include: 
Concurrent field and laboratory studies to establish the significance of, and to de- 
velop or improve predictive techniques for, assessing contaminant bioaccumulation 
and biomagnification associated with the aquatic disposal of dredged material. 
Continued field tests of procedures to eliminate or minimize adverse impacts of 
dredged material disposal through capping contaminated material with non-con- 
taminated material. 
Improved plant and animal bioassays for predicting impacts of dredged material 
disposal within alternative disposal media, such as wetland and upland areas. 
Concurrent field and laboratory studies to assess geochemical changes that occur 
with time within upland containment areas for dredged material, and to develop im- 
proved techniques for predicting contaminant concentrations in the effluent from 
these sites. 
In addition to this mator program, a unique opportunity for dredged material re- 
search has recently been identified and is now underway within the Black Rock 
Harbor Federal navigation project in Connecticut. This study, which is a joint effort 
between the Corps and EPA, will address the issue of objective evaluation of dispos- 
al alternatives by documenting and verifying techniques for predicting environmen- 
tal effects of contaminants due to aquatic, upland, and wetland (marsh creation) dis- 
posal. This will all be done with dredged material from a single routine mainte- 
nance operation, providing an unusual opportunity for direct comparison of overall 
environmental consequences of the same material under different disposal condi- 
tions. 
Under this program, existing bioaccumulation techniques, as well as promising 
new predictive techniques recently developed by EPA, will be thoroughly tested in 
the laboratory for reproducibility and precision, and verified in the field as to the 
accuracy of each technique in predicting environmentally significant changes in bio- 
logical communities and ecosystems. In out-years, techniques which prove useful at 
this site will also be field verified at other aquatic, upland, and wetland sites to 
demonstrate their wide applicability. 
The Corps is also the lead Federal agency for the international exchange of scien- 
tific and engineering techniques regarding the management of bottom sediments 
containing toxic substances. Joint meetings on this subject have been held each year 
since 1976 between senior scientists and engineers of the United States and Japan. 
Major topics of information exchange under this Memorandum of Understanding 
(MOU) have included advances in dredging technology; assessment of innovative 
