413 
It is reasoned that consideration of the eligibility for dumping of dredged 
material containing Annex I substances could be handled on a case-by-case 
basis, particularly if there is appropriate assurance that, through the use 
of "special care" measures, the substance may be safely disposed in the 
marine environment. 
WORKING DEFINITIONS OF ANNEX I AND II PARAMETERS 
The three Annex I properties of being toxic, of being susceptible to bioac- 
cumulation, and of being persistent or refractory to degradation in the en- 
vironment are legitimate concerns; however, we have come to learn more and 
more about the fate of pollutants in the marine environment from field 
studies and there is little hard evidence that dredged material has caused 
substantial biological damage in the ocean. 
Toxic. To state that a constituent of any material is toxic is equiva- 
lent to saying that it is poisonous and capable of causing death. But to 
indicate that a given toxicant is present in dredged material is not tanta- 
mount to admitting that it will be available to the organisin or, if it is, 
that the organism will suffer acute or chronic impacts. Several chemical 
characteristics comuon to many dredged materials, such as adsorption on 
clay, complexing with organic matter, or reducing conditions may favor im- 
mobilization of the toxicant. Also, organisms have many adaptations to 
their chemical environment; two of these are (1) to remove the toxicant from 
its metabolic streams by sequestering it in one or more storage depots, or 
(2) degradation or transformation of the molecule into an innocuous sub- 
stance and into residues which are eliminated in a process of depuration. 
"Special care" measures of disposal can augment environmental sequestering 
of toxicants. 
Bioaccumulation. Bioaccumulation refers to those processes by means of 
which organisms take up chemicals from the physicochemical environment and 
incorporate them into some or all of their tissues. The concern with this 
process is that the organism will accumulate levels of toxicants well above 
those in the ambient environment so that it will become a hazard to preda- 
tory animals, including man. 
