VI-240 



it may be pertinent In understanding the action of organic 

 residues. The forms in which the metals exist are import- 

 ant factors in their biological activity. 



Chemistry of Particles and 

 Processes in Sediments 



(1) Experiments should be carried out to establish the 

 effects on soluble components, particularly waste solutes, 

 of flocculation, aggregation, coprecipitation, and sorption. 

 A study should be made of the physical -chemical factors and 

 the role of organisms in affecting the flocculation rates of 

 sediments In estiaries and coastal waters. Pertinent vari- 

 ables appear to be in the degree of dilution •/ fresh water 

 suspensions entering sea water, the levels of organic 

 matter, the pH of the mixture, the oxidation potential, the 

 relative percentages of different clay minerals and other 

 solid phases, the mlting characteristics of the flow, and 

 the temperature. 



(2) The rates of aggregation and sedimentation of organic 

 particles in the marine environment should be studied. Such 

 factors as pH, temperature, organic-metal ion complexing at 

 organic particle surfaces, and the concenftration of 

 inorganic particles should be evaluated. Organic debris 

 appears to play a role in transporting trace metals to the 

 sediments. The organic debris may associate with inorganic 



