ABSTRACT
CONTENTS Introduction .............................................................................................................................................. 79 Methods.................................................................................................................................................... 80
Study Areas .................................................................................................................................... 80 Sediment Collection and Preparation ............................................................................................ 80 Particle Size Distribution and Total Organic Carbon.................................................................... 82 Sediment Chemical Quality ........................................................................................................... 82 Sediment Biological Quality.......................................................................................................... 82
Whole Sediment and Pore Water Toxicity: Animal Species............................................ 82 Whole Sediment Phytotoxicity: Early Seedling Growth.................................................. 83 Microbial Genotoxicity ..................................................................................................... 83 Benthic Community Composition .................................................................................... 83
Results ...................................................................................................................................................... 83 Particle Size Distribution and Total Organic Carbon (TOC) ........................................................ 84 Chemical Quality............................................................................................................................ 84
Effects-Based Exceedances............................................................................................... 84 Geochemically Based Enrichment.................................................................................... 85
Acute and Chronic Toxicities......................................................................................................... 85 Microbial Genotoxicity .................................................................................................................. 85 Phytotoxicity: Early Seedling Growth ........................................................................................... 85 Benthic Macroinvertebrate Community......................................................................................... 89 Temporal Variability ....................................................................................................................... 90
Discussion ................................................................................................................................................ 90 Stressor Ranking ............................................................................................................................ 90 Metric Concordance ....................................................................................................................... 91 Data Comparisons .......................................................................................................................... 93
Recommendations .................................................................................................................................... 95 Acknowledgments.................................................................................................................................... 96 References ................................................................................................................................................ 96
The Gulf of Mexico is an economic and natural resource that receives anthropogenic contamination from a variety of sources (Truax and Daniel, 1991). Approximately 3700 wastewaters, the most for any U.S. coastal area, are discharged into near-coastal waters. In addition, four of the five states that led the nation in surface water discharges of toxic chemicals are located in the Gulf region (U.S. EPA, 1994a) and approximately 4.5 × 106 kg of registered pesticides were applied to estuarine drainage areas in 1987, the most for any coastal region (Pait et al., 1992). As a result of these anthropogenic inputs, approximately
62% of Gulf of Mexico estuaries are negatively affected by contaminants (U.S. EPA, 2001a), and 233 waters are listed as impaired (U.S. EPA, 2001a). More specifically, about 2850 km2 of Florida’s estuaries are partially impaired and only 16 of 10460 km2 attain all designated uses (FDEP, 2002). Despite the environmental degradation, the relative contributions of specific contaminant sources to the impairments are usually unknown.
