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6818539 
Technical Report 
Organic pollution of the water in the Black Creek Vicinity, Biscayne National Park 
Corcoran, EF; Brown, MS; Freay, AD 
1987 
United States Department of the Interior, National Park Service 
Atlanta, GA 
PB88213699 
24 
English 
In June 1980 the boundaries of Biscayne National Park were extended to include Black Creek, an area that had been of ecological concern for several years. Prior to acquisition, local commercial fishermen had complained of fish kills and reduced catches and elevated water-column turbidity, ammonia and phosphate concentrations, and lower salinities as compared to other canals in lower Biscayne Bay and Card Sound were reported. As a result of these concerns, the National Park Service funded a study to investigate the possible causes of several of the changes that were taking place in the Black Creek area. The objectives were to document benthic community structure and to determine if groundwater upwelling might be a source of nutrients and chlorinated pesticides. The detection of insecticides and phthalic acid esters (PAEs) in the Black Creek area was not surprising since previous studies have confirmed their presence in the sediments. In addition, the extensive use of the drainage area of the creek for agricultural purposes would certainly provide a source. What is important to note is that these compounds were detected in the pore water indicating that they can become mobile and be introduced into the water column. The groundwater could transport contaminants from inland agricultural areas or landfill disposal sites. Although the results from this study, regarding the occurrence and magnitude of groundwater upwelling we inconclusive, the sediment pore waters did indicate contamination by insecticides and PAEs. Analysis of pore water for chlorinated pesticides, PCBs, and PAEs in the area north of Black Creek indicated that this area was degraded more than the impacted or southern comparison site. Mean sample concentrations in the northern comparison site were three times that at the impacted site and there were 0.6 more compounds/sample. This area had particularly high concentrations of DDD, DDT, dieldrin, endosulfan, and heptachlor epoxide. These compounds, although presently banned or use restricted in the U.S., are all very effective, commonly used agriculture foliar or soil insecticides. (Lantz-PTT)