Effects on Survival, Reproduction and Growth of Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium Page: 2
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Turner, Philip K., Effects on Survival, Reproduction and Growth of
Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium.
Doctor of Philosophy (Environmental Science), August 2005, 165 pp., 22 tables, 31
figures, references, 107 titles.
Effects of episodic exposures have gained attention as the regulatory focus of
the Clean Water Act has shifted away from continuous-flow effluents. Standardized
laboratory toxicity tests require that exposure be held constant. However, this approach
may not accurately predict organism responses in the field following episodic exposures
such as those associated with rain-driven runoff events or accidental pollutant
discharge. Using a modified version of the 7-day short-term chronic test recommended
by the US Environmental Protection Agency, Ceriodaphnia dubia were exposed to
copper or cadmium for durations ranging from 1 minute to 24 hours. In addition, adult
reproductive recovery and effects on second generation individuals was assessed
following select copper exposures. Finally, cadmium exposures were compared in
reconstituted hard water (RHW) and municipal treated wastewater effluent (TWE).
Following exposure, organisms were transferred to clean RHW or TWE and maintained
for the remainder of the test. No- and lowest observed effect concentrations (NO- and
LOECs) increased logarithmically with respect to logarithmic decreases in duration
regardless of metal, endpoint or water type. Effective concentrations of cadmium
however, were usually higher than those of copper, especially in TWE. LOECs for C.
dubia survival following 24-hour and 5-minute exposures to copper were 116 and 417
pg/L, respectively. LOECs for fecundity were 58 and 374 pg/L, respectively. Neonate
production of first generation adult C. dubia appeared to recover from pulsed copper
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Turner, Philip K. Effects on Survival, Reproduction and Growth of Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium, dissertation, August 2005; Denton, Texas. (https://digital.library.unt.edu/ark:/67531/metadc4831/m1/2/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; .