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## Acute Toxicity to Aquatic Plants

CAS Number : 3194-55-6 Sponsored Chemical Name : Cyclododecane, 1,2,5,6,9,10-hexabromo
### Test Substance - Acute Toxicity To Aquatic Plants
Test Substance: (25637-99-4) Cyclododecane, hexabromoTest Substance Purity/ Composition and Other Test Substance Comments: Estimated by Calculation

Test Substance Result Type: Estimated 

### Method - Acute Toxicity To Aquatic Plants Year Study Performed: 2004

Method/ Guideline Followed: OECD 201

Other Method/ Guideline:
Deviations from Method/ Guideline: Species: Skeletonema costatum
GLP: Yes Analytical Monitoring: Yes
Test Type:
Test Vessel:
Water Media Type:
Test Concentrations:
Nominal and Measured Concentrations:

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Exposure Period: 72 Hours

Vehicle Used:
Vehicle Name:
Vehicle Amount and Units: Alkalinity:
Dissolved Oxygen: pH Value:
Test Temperature and Units: Photo (Light/ Dark): Salinity:
TOC:
Water Hardness:
Method/ Guideline Test Conditions Remarks: HBCD: A 72-Hour toxicity test with the marine diatom (Skeletonema costatum) The objective of this study was to determine the toxicity of water-soluble components of hexabromocyclododecane (HBCD) to the marine diatom Skeletonema costatum, using a saltwater algal media passed through a generator column saturated with HBCD. This study was performed according to Good Laboratory Practices, IS0 10253:1995, OECD 201, and EU Directive 92/69/EEC, Method C.3. The test article was a composite of the commercial products of Albemarle Corporation, Dead Sea Bromine Group and Great Lakes Chemical Corporation. Composite = 7.67% alpha, 5.15% beta and 83.04% gamma. The experimental design was developed based on prelminary work. The marine diatom was exposed to a single test concentration (produced via water generator column) of HBCD in salwater algal media, a negative control (also referred to as Control with Column) and a media control (also referred to as Control no Column) for 72 hours. The single test concentration was prepared using algal media passed through a comlumn generator packed with a solid support coate with HBCD to achieve the test concentraiton of HBCD in saltwater algal medium. Measured test concentrations were determined from samples of test medium collected from teh treament and each control group at the beginning of the test and at test termination. At test initiation an inoculum of the algal cells was added to each test chamber to achieve a nominal concentratin of approximately 77,000 Skeletonema cells/ml. Samples were collected from each replicate test chmaber at approximately 24-hour intervals during the test to determine cell densities, which were subsequently used to caluculate areas under the growth curve (biomass) and growth rates. Cell densitites, biomass and growth rates were used to calculate percent inhibitoin vlaues relative to the control over the 72-hour exposure period. No-oberved-effect-concentrations (NOEC) were determ ined at 72 hours through statistical evaluation of the cell densities, biomass and growth rates, as well as examination of the concentration-response pattern. The analytical method for the 3 HBCD stereoisomers in saltwater algal medium was based on methodology developed by Wildlife International LTD. It used an HPLC interfaced with a triple quadrupole LC mass spectromer operated in single-quadrupole selective ion monitoring mode. The LOQ was 0.5 ug a.i./L. The Day 0 and 3 arithmetic mean measured test concentrations for Gamma, Beta, Alpha and total HBCD was 1.61, 8.86, 30.5 and 41.0 ug a.i./L, respectively. Arithmetic mean measured test concentrations were used to calculate the NOEC values.

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Limit Test: 

### Test Results - Acute Toxicity To Aquatic Plants NOEC Exposure Duration:
NOEC: < 41 LOEC Exposure Duration:
LOEC:
NOELR Exposure Duration:
NOELR:
LOELR Exposure Duration:
LOELR:
Effect: Exposure Duration Exposure Units Type % Value Description Mean Value or Lower Mean Value Upper Mean Value Units Basis for Effect Basis for Concentration

EC 50 % > 41 ug/L

Results Remarks: S. costatum were exposed to a single concentraion of 41 .O ug a.i./L of toal HBCD and evaluated for effects on cell density, area under the growth curve (biomass) and growth rate. After 72 of exposure, inhibition of cell density, biomass and growth rate in the treated group was 19, 21 and 7.3%, respectively, relative to control no column. Similarly, relative to the control with column, inhibition of cell density, biomass and growth rate was 31, 31 and 11%, respectively. The treated group was statistically different from both control groups (p<0.05) Since there were effects observed, the 72 hour NOEC and EC50, based on cell density, biomass and growth rate were < 41.0 ug a.i./L and > 41.0 ug a.i./L total HBCD, respectively. The total HBCD concentration was composed of 1.61 ug a.i./L gamma; 8.86 ug a.i./L beta and 30.5 ug a.i./L alpha isomers.



### Reliability/Data Quality - Acute Toxicity To Aquatic Plants Reliability: Valid Without Restrictions Reliability Remarks: Risk Assessment, Critical study for SIDS endpoint
Key Study Sponsor Indicator: 

### Reference - Acute Toxicity To Aquatic Plants
Reference: Desjardins D, MacGregor J, Krueger H. 2004. Hexabromocyclododecane (HBCD): a 72-hour toxicity test with the marine diatom (Skeletonema costatum). Final Report. Wildlife International LTD Project Number: 439A-125. Wildlife International LTD, Easton, MD.

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