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Abstract

Acute toxicity tests were conducted with Hyalella azteca Saussure (an amphipod) exposed in soft and hard waters to three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex). The chemicals were slightly to moderately toxic to amphipods. The most toxic chemical to amphipods in soft and hard water was Phos-Chek WD-881 (96-h mean lethal concentration [LC50] equal to 10 mg/L and 22 mg/L, respectively), and the least toxic chemical to amphipods in soft water was Fire-Trol GTS-R (96-h LC50 equal to 127 mg/L) and in hard water was FireTrol LCG-R (96-h LC50 equal to 535 mg/L). Concentrations of ammonia in tests with the three fire retardants and both water types were greater than reported LC50 values and probably were the major toxic component. Estimated un-ionized ammonia concentrations near the LC50 were frequently less than the reported LC50 ammonia concentrations for amphipods. The three fire retardants were more toxic in soft water than in hard water even though ammonia and un-ionized ammonia concentrations were higher in hard water tests than in soft water tests. The accidental entry of fire-fighting chemicals into aquatic environments could adversely affect aquatic invertebrates, thereby disrupting ecosystem function.

Keywords -- ammonia, amphipods, fire retardants, fire suppressants, Hyalella azteca

McDonald, Susan F., Steven J. Hamilton, Kevin J. Buhl,  and James F. Heisinger.
     1995.  Acute toxicity of fire-retardant and foam-suppressant chemicals to
     Hyalella azteca (Saussure).  Environmental Toxicology and Chemistry.
     16(7):1370-1376.
     

McDonald, Susan F., Steven J. Hamilton, Kevin J. Buhl,  and James F. Heisinger.
     1995.  Acute toxicity of fire-retardant and foam-suppressant chemicals to
     Hyalella azteca (Saussure).  Environmental Toxicology and Chemistry.
     16(7):1370-1376.  Northern Prairie Wildlife Research Center Online. 
     http://www.npwrc.usgs.gov/resource/othrdata/fireweb/hyalazte.htm
     (Version 02MAR98).

Table of Contents

• Introduction
• Materials and Methods
  • Culture
  • Dilution Water
  • Test Chemicals
  • Acute Toxicity Testing
  • Ammonia Analysis
  • Statistical Analysis
• Results
  • Water Quality
  • Acute Toxicity
  • Ammonia
• Discussion
  • Water Quality
  • Acute Toxicity
  • Ammonia
  • Trophic Interactions
  • Relationship to Environmental Considerations
• Conclusions
• References
• Appendix

Tables

• Table 1. -- Acute toxicity of five fire-retardant chemicals to adult Hyallela azteca exposed in American Society for Testing and Materials soft and hard waters.
• Table 2. -- Summary of the ammonia characteristics of five fire-retardant chemicals used in tests with adult Hyallela azteca exposed in American Society for Testing and Materials soft and hard waters.
• Table 3. -- Formulation of field mixtures for five fire-fighting chemicals and the ratio of the mixture concentration to the acute toxicity value.

Acknowledgments

This study was sponsored by the Interior Fire Coordinating Committee, U.S. Department of the Interior. We thank A. Bullard, M. Ehlers, and M. Gaikowski for technical assistance in conducting toxicity tests, K. Faerber for typing the manuscript, B. Poulton, P. Haverland, C. George, and three anonymous reviewers for helpful reviews.