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Hydrologic Modeling



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Baseline Aquatic Contamination and Endocrine Status in Resident Fish Populations of Biscayne National Park and in the Adjacent Coastal Environment

Project Chief: Timothy Bargar, Southeast Ecological Science Center
Cooperator: National Park Service
Period of Project: October 2010 - September 2013

Problem Statement

Figure 1. Location of the coastal wetlands that will be re-hydrated and the South District Wastewater  Treatment Plant in relation to Biscayne National Park.

Figure 1. Location of the coastal wetlands that will be re-hydrated and the South District Wastewater  Treatment Plant in relation to Biscayne National Park.

Contaminant monitoring in Biscayne Bay (the Bay) has focused on current and legacy pesticides as well as on metals and other industrial pollutants. However, the existence of landfills, septic tank effluents, leaky sewer lines, and land application of wastewater or wastewater solids within the drainage basin of the Bay create the potential for the occurrence of organic wastewater compounds (OWCs) within the Bay and canals entering the Bay. A proposal to use treated wastewater for rehydration of coastal wetlands has led to a concern that OCWs could ultimately enter the Biscayne National Park (the Park) (fig. 1) and adversely impact aquatic biota. . Other studies have reported incidences of endocrine disruption in fish as a result of exposure to treated wastewater effluents. Without an assessment of pre-hydration conditions, it would be difficult to differentiate between impacts from the WWTP effluent and other OWC sources in the region.


1) Determine the occurrence of OWC in surface waters, sediments, and fish of Biscayne Bay, influent canals, and coastal wetlands, and the influence of seasonality (wet and dry season) on OWC inputs

2) Identify potential sources of OWCs for Biscayne Bay

3) Determine the potential for endocrine disruption from the OWCs that are present, as well as the current endocrine status of a selected resident fish species


The study was limited primarily to Biscayne National Park and the water ways (i.e., canals) in the vicinity of potential OWC sources for the Park. Tarpon Bay in the adjacent Florida Bay served as a reference.

Passive samplers (SPMD and POCIS) were used to determine OWC occurrence and concentrations (when possible), in surface waters of the Bay, canals, and coastal wetlands. During the wet and dry season of the first year of the project, passive samplers were deployed at the mouths of the nine canals that discharge into the Bay, at three different locations within the Bay, and at three locations within the coastal wetlands that are the subject of the rehydration plans. The samplers were left in place for approximately one month at which time they were retrieved and prepared for shipment to the Columbia Environmental Research Center. The SPMD and a subset of the POCIS in each passive sampler were used to assess contamination in the surface waters of the respective locations.

During the wet season, composite sediment samples were collected from each Bay, coastal wetland, and canal mouth location at the time of sampler retrieval. Any compounds present in the sediment samples could be an indication of their long-term presence in the water column and indicate their fate in the Bay and coastal wetlands.

Fish samples (crested goby Lophogobius cyprinoides) were collected from locations in the Bay, coastal wetlands, and the canal mouth during the wet season to assess contaminant bioavailability. Due to the small size of the goby and the costs associated with extraction and analysis, 10 gobies collected from a location were composited to provide sufficient sample size for detection of low contaminant concentrations. The composited samples were analyzed to determine OWC concentrations. The fish data can provide a useful correlate of contamination in the surface waters and sediments of the respective locations as well as an indication of bioavailability. Analyses also were conducted for estrogenicity and endocrine status.


Not yet available

Information Product

A USGS Scientific Investigation Report will describe the environmental contamination and endocrine status in resident fish populations of Biscayne National Park and in the adjacent coastal environment.

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