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7. Developing Site-Specific Water Quality Criteria
Example 4: Examining a Proposed Criterion
The proposed criterion for chronic exposure is 15 Ilg SelL, and the
following information is available for the HU (Ilg Selg concentrations
are in dry weight):
Waterborne concentrations of selenium are 10-20 Ilg/L.
Concentrations of selenium in sediments are 1-2 Ilg/g.
Concentrations of selenium in aquatic food-chain organisms are 1-3 Ilg/g.
Concentrations of selenium, terata, and embryomortality in randomly
sampled aquatic bird eggs are unavailable because few aquatic
birds nest at the site.
Concentrations of selenium in whole-body samples of fish are 2-5 Ilg/g.
Teratogenic deformities occurred in 0% offish from ichthyoplankton
samples.
Concentrations of selenium in ichthyoplankton samples are 3-6 Ilg/g.
Possible impacts to down-gradient systems are unknown.
Evaluation: No reproductive effects are evident in fish, and potential
threats to aquatic birds are likely minimal because few of them were
found to nest or feed at the site. However, the habitat usage and selenium status of some river habitats and associated wetlands have not
been characterized. Moreover, concentrations of selenium in fish are
at the lower end of the diagnostic toxicity range.
Conclusion: The proposed criterion of 15 Ilg SelL is rejected because
of possible threats to down-gradient systems in the HU as well as the
presence of elevated selenium residues in fish and food-chain organisms. Monitoring of selenium residues in fish and down-gradient habitats is recommended.
Conclusions
During the past 2 decades, selenium has gained a reputation as an important aquatic contaminant, and it is currently classified as one of the USEPA's
priority pollutants. The USEPA issued a revised (lowered) national freshwater criterion for selenium in 1987, but there is considerable disagreement as to the applicability of the national criterion at the state and local
levels. Some believe it should be lowered; some believe it should be
raised. This has led to more and more instances of states and municipalities attempting to develop site-specific criteria. However, there is no published or widely accepted technique available that gives specific guidance
for selenium. The method presented in this chapter should fill that infor-
7. Developing Site-Specific Water Quality Criteria
Example 4: Examining a Proposed Criterion
The proposed criterion for chronic exposure is 15 Ilg SelL, and the
following information is available for the HU (Ilg Selg concentrations
are in dry weight):
Waterborne concentrations of selenium are 10-20 Ilg/L.
Concentrations of selenium in sediments are 1-2 Ilg/g.
Concentrations of selenium in aquatic food-chain organisms are 1-3 Ilg/g.
Concentrations of selenium, terata, and embryomortality in randomly
sampled aquatic bird eggs are unavailable because few aquatic
birds nest at the site.
Concentrations of selenium in whole-body samples of fish are 2-5 Ilg/g.
Teratogenic deformities occurred in 0% offish from ichthyoplankton
samples.
Concentrations of selenium in ichthyoplankton samples are 3-6 Ilg/g.
Possible impacts to down-gradient systems are unknown.
Evaluation: No reproductive effects are evident in fish, and potential
threats to aquatic birds are likely minimal because few of them were
found to nest or feed at the site. However, the habitat usage and selenium status of some river habitats and associated wetlands have not
been characterized. Moreover, concentrations of selenium in fish are
at the lower end of the diagnostic toxicity range.
Conclusion: The proposed criterion of 15 Ilg SelL is rejected because
of possible threats to down-gradient systems in the HU as well as the
presence of elevated selenium residues in fish and food-chain organisms. Monitoring of selenium residues in fish and down-gradient habitats is recommended.
Conclusions
During the past 2 decades, selenium has gained a reputation as an important aquatic contaminant, and it is currently classified as one of the USEPA's
priority pollutants. The USEPA issued a revised (lowered) national freshwater criterion for selenium in 1987, but there is considerable disagreement as to the applicability of the national criterion at the state and local
levels. Some believe it should be lowered; some believe it should be
raised. This has led to more and more instances of states and municipalities attempting to develop site-specific criteria. However, there is no published or widely accepted technique available that gives specific guidance
for selenium. The method presented in this chapter should fill that infor-