Environmental Profiles of Chemical Flame-Retardant Alternatives for

Algal Toxicity (OPPTS Harmonized Guideline 850.5400; OECD Guideline 201)
Conclusion:
The available algal toxicity data were judged tentatively adequate to meet the endpoint, pending
the availability of additional information from the studies that were not included in the published
articles.
Basis for Conclusion:
Seventy-two-hour static studies in Selenastrum capricornutum, Scenedesmus subspicatus,
Chlorella vulgaris (Millington et al., 1988), a 96-hour static study in Selenastrum capricornutum
(Mayer et al., 1981), and a 22-day study in Ankistrodesmus falcatus were located. These data are
summarized in Table 1-3. Taken together, these data may be adequate; however, additional
information is needed from the studies before they can be used as the basis for satisfying the
algal toxicity endpoint.
Millington et al. (1988) conducted a series of 72-hour static studies that were designed to
evaluate the influence of various standard test media (OECD, U.S. EPA, and Bold’s basal) on the
toxicity of triphenyl phosphate to three algal species, Selenastrum capricornutum, Scenedesmus
subspicatus, and Chlorella vulgaris. These static studies followed OECD Guideline 201. Five
concentrations ranging from 0.05 to 5 mg/L were tested in triplicate cultures. The test
concentrations were not analytically confirmed. The resulting 72-hour NOAEC values ranged
from 0.1 to 1 mg/L depending on the algal species tested and the test media used. EC50 values
were not derived, and raw data were not available to allow for an independent calculation of
EC50 values. Overall, the studies appear to have been adequately conducted. Deficiencies in
the data included reporting deficiencies (e.g., raw data, water quality values determined during
the study, and growth of control replicates), lack of analytical confirmation of the test
concentrations, and lack of EC50 determinations. Provided that the missing study details can be
obtained and that an EC50 value can be determined, these data appear adequate to satisfy the
algal toxicity endpoint.
Mayer et al. (1981) conducted a 96-hour static test in Selenastrum capricornutum. Many details
from this study were obtained from the unpublished report submitted to EPA (EG&G
Bionomics, 1978d). Five concentrations that ranged from 0.6 to 10 mg/L were tested. Test
concentrations were not analytically confirmed. An EC50 of 2 mg/L (95% confidence interval
of 0.6-4 mg/L) was derived from this study. A clear NOAEC was not established because a 4%
decrease in cell number and a 15% decrease in chlorophyll-" concentration was observed at the
lowest concentration of 0.6 mg/L. Although the study appears to have been adequately
conducted, initial and final cell concentrations of controls or treated cultures were not reported.
Provided that these study details can be obtained, the 96-hour EC50 reported in this study
appears to be adequate to satisfy the short-term algal toxicity endpoint. It should be noted that
the EC50 determined from this study is at the approximate water solubility limit of TPP (2
mg/L). The lack of a clear NOAEC precludes the use of this study as the sole basis to satisfy the
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