Marsh Total 1 10 17 



Sites Dissolved 10 17 



Southern Total 12 40 



Canal Sites Dissolved 6 14 



Marsh 

 Sites 



Total 



Dissolved 



5 22 

 5 22 



Southern Total 6 25 



Canal Sites Dissolved 3 25 



36 300 



26 280 



14 30 



9 25 



±3_ 



MAM 

 i v a 

 n q x 



28 150 0.0 0.1 0.8 



46 40 



34 250 0.0 0.1 1.0 



20 40 



30 780 2500 



90 740 1400 



Table 14. Average, minimum, and maximum concentrations of trace metals 



in surface waters of Conservation Area 3 (in micrograms per liter) 

 (adapted from Waller and Earle 1975). 



sawgrass, wet prairies, and other 

 Everglades communities indicates 

 that the sediments act as a sink for 

 these materials entering the system 

 either in solution or in particulate 

 form. As water, sediment, and de- 

 tritus move through the glades, some 

 of this material may be recycled. 



In general, canals which cut 

 through and drain the organic soils 

 disrupt their function as a nutrient 

 and pesticide sink. Lowering water 

 levels exposes the soils to oxida- 

 tion causing the release of bound 

 nutrients, organic moities, inorgan- 

 ic ions, and trace metals which 

 remained tied up under the reducing 

 conditions necessary for peat accu- 

 mulation. Waller and Earle (1975) 

 report relatively higher concentra- 

 tions of nutrients in the marsh 

 soils than in the canal sediments; 

 and higher concentrations of trace 

 metals in canal sediments than in 

 marsh soils. Pesticide concentra- 

 tions in all sediments declined with 



distance away from agricultural 

 operations. Apparently the canals 

 serve as a mechanism for hastening 

 the export of trace metals and 

 organic matter, as well as water, 

 from the conservation areas. Unfor- 

 tunately, they are exported to 

 urbanized areas and estuaries where 

 they are not necessarily wanted. 



5.3 SHARK RIVER SLOUGH AND 

 ASSOCIATED ESTUARIES 



Flow through the Tamiami Canal 

 spillways generally peaks in October 

 due to the corresponding peak in 

 rainfall (Leach et al. 1972), while 

 minimum flows occur in April and May 

 just prior to the onset of the wet 

 season. Considerable variation in 

 this general pattern occurs from 

 year to year, however, as evidenced 

 in Figure 33a of monthly average 

 flows from a variety of years. 



As expected, water movement 

 through Shark River Slough, in any 



77 



