Listing Guideline

When wildlife survey data confirm the presence of deformities (e.g. cross-bill syndrome) or other reproductive problems (e.g. egg-shell thinning) in sentinel wildlife species.

Delisting Guideline

When the incidence rates of deformities (e.g. cross-bill syndrome) or reproductive problems (e.g. egg-shell thinning) in sentinel wildlife species do not exceed background levels in inland control population.

Delisting Targets

This BUI can be removed if:

  • Studies conducted in the AOC indicate that the beneficial use should not be considered impaired, or
  • If studies conducted in the AOC determine that this use is impaired, then two approaches can be considered for delisting:
    • Approach 1 – Observational Data and Direct Measurements of Birds and other Wildlife
      • Evaluate observational data of bird or other animal deformities for a minimum of two successive monitoring cycles in indicator species identified in the initial studies as exhibiting deformities or reproductive problems.  If deformity or reproductive problem rates are not statistically different than those at minimally impacted reference sites (at a 95% confidence interval), or no reproductive or deformity problems are identified during the two successive monitoring cycles, then the BUI can be removed.  If the rates within the AOC are statistically higher than the reference site, it may indicate a source from either within or from outside the AOC.  Therefore, if the rates are statistically higher or the data are insufficient for analysis to achieve agreed upon statistical power, then…
      • Evaluate tissue contaminant levels in egg, young and/or adult wildlife.  If contaminant levels are lower than the Lowest Observable Effect Level (LOEL) for that species for a particular contaminant that are not statistically different than those at minimally impacted reference sites (at a 95% confidence interval), then the BUI can be removed.
      • Where direct observation of wildlife and wildlife tissue data are not available, the following approach should be used:
    • Approach 2 – Fish Tissue Contaminant Levels as an Indicator of Deformities or Reproductive Problems
      • If fish tissue concentrations of contaminants known to cause deformities or reproductive suppression identified in the AOC are at or lower than the LOEL known to cause reproductive or developmental problems in fish-eating birds and mammals, the BUI can be delisted, or
      • If fish tissue concentrations of contaminants known to cause deformities or reproductive suppression identified in the AOC are not statistically different than Lake Michigan (at 95% confidence interval with sufficient and agreed upon statistical power), then the BUI can be removed.  Fish of a size and species considered prey for the wildlife species under consideration must be used for the tissue data.

Sources of Pollution or Problem

  • Contaminated sediments; spills of chemicals within the watershed; atmospheric deposition
  • Sediment, nutrients, and bacteria as a result of nonpoint, or diffuse, sources of pollution; urban stormwater runoff; sewer overflows; noncontact cooling water

Remediation Actions

USGS has been using tree swallows as indicators of environmental contamination in areas across the United States, and they previously sampled at least one site in the Milwaukee Estuary. In 2015 five sites were sampled, including; Cedar Creek, Lincoln Park, Three Bridges Park, Lakeshore State Park and Baran Park. This represents one site each on Cedar Creek, Milwaukee River, Menomonee River, Kinnickinnic River and in the Estuary. This sampling will provide data robust enough to determine if this beneficial use is impaired. Preliminary data from USGS for 2015 indicate contaminants are present and further assessment may be needed to determine impairment status.

Relevant USGS Studies:

  http://cida.usgs.gov/glri/projects/toxic_substances/birds_as_indicators.html

  http://www.umesc.usgs.gov/wildlife_toxicology/glri_project80.html

Moving Forward

Continued sampling is needed to gather adequate data to determine whether this is an impaired use in the AOC. Sampling by USGS at the suite of sites in the AOC appears to be the best course of action to assess this impairment.

Issues

Until recently, limited data have been available to aid in the assessment of this impairment.

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Photo courtesy of Christine Custer, USGS