Co-Author(s)

Wayne Landis

Research Mentor(s)

Wayne Landis

Affiliated Department

Environmental Sciences

Sort Order

53

Start Date

14-5-2015 10:00 AM

End Date

14-5-2015 2:00 PM

Keywords

Species sensitivity distribution (SSD), Eecotoxicological tools

Document Type

Event

Abstract

For three decades, the species sensitivity distribution (SSD) has been the primary ecotoxicological tool to assess the effects of toxicants on species biodiversity. Despite prolific use by international environmental protection organizations and application in a wide range of ecosystems, there are several problems. 1) The hazardous concentration to protect 95% of a taxonomic group (HC5) is rejecting a portion of species that may have significant ecological roles. 2) Confidence intervals are entirely based on the number of species available with toxicological data and infer a large range of what is considered a “safe” concentration. 3) The minimum sample size to produce an SSD produces broad confidence intervals. 4) The parameters for data inputs to produce SSDs are not universal. 5) The trophic structure for an endpoint or location is not considered. In this research we use four taxonomic groups were used to represent a riparian food web; phytoplankton, zooplankton, macroinvertebrates, and predators. Individual and community SSDs were generated using zinc and copper with at least 10 species from each taxonomic group. Our findings suggest that the phytoplankton HC5 is less than zooplankton, macroinvertebrates, and predators. Furthermore, the range defined by confidence intervals for phytoplankton is from 0.06 ug/L to 33.23 ug/L indicating a high degree of uncertainty for a safe regulatory concentration to protect multiple trophic levels. Since copper is an algaecide, the HC5 toxicity is greater than zinc for a community SSD. Future studies of SSDs must incorporate trophic response to phytoplankton toxicants, and trophic levels in toxicant regulation.

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this documentation for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Language

English

Format

application/pdf

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May 14th, 10:00 AM May 14th, 2:00 PM

Trophic Response to Multiple Stressors Using Species Sensitivity (SSD) Distribution Models

Environmental Sciences

For three decades, the species sensitivity distribution (SSD) has been the primary ecotoxicological tool to assess the effects of toxicants on species biodiversity. Despite prolific use by international environmental protection organizations and application in a wide range of ecosystems, there are several problems. 1) The hazardous concentration to protect 95% of a taxonomic group (HC5) is rejecting a portion of species that may have significant ecological roles. 2) Confidence intervals are entirely based on the number of species available with toxicological data and infer a large range of what is considered a “safe” concentration. 3) The minimum sample size to produce an SSD produces broad confidence intervals. 4) The parameters for data inputs to produce SSDs are not universal. 5) The trophic structure for an endpoint or location is not considered. In this research we use four taxonomic groups were used to represent a riparian food web; phytoplankton, zooplankton, macroinvertebrates, and predators. Individual and community SSDs were generated using zinc and copper with at least 10 species from each taxonomic group. Our findings suggest that the phytoplankton HC5 is less than zooplankton, macroinvertebrates, and predators. Furthermore, the range defined by confidence intervals for phytoplankton is from 0.06 ug/L to 33.23 ug/L indicating a high degree of uncertainty for a safe regulatory concentration to protect multiple trophic levels. Since copper is an algaecide, the HC5 toxicity is greater than zinc for a community SSD. Future studies of SSDs must incorporate trophic response to phytoplankton toxicants, and trophic levels in toxicant regulation.

 

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