Hexabromocyclododecane

Long-term toxicity to fish

Description of key information

The following information is available for this endpoint:
Drottar, K. R., MacGregor, J. A. and Krueger, H. O. (2001). Hexabromocyclododecane (HBCD): An early life-stage toxicity test with the Rainbow Trout (Oncorhynchus mykiss). Report no.: 439A-112. Report date: 2001-07-12.
Ronisz, D., Farmen Finne, E., Karlsson, H. and Förlin, L. (2004). Effects of the brominated flame retardants hexabromocyclododecane (HBCDD), and tetrabromobisphenol A (TBBPA), on hepatic enzymes and other biomarkers in juvenile rainbow trout and feral eelpout. Aquatic Toxicology (2004), Vol. 69, pp.229-245.
Kuiper, R. V., Cantón, R. F., Leonards, P. E. G., Jenssen, B. M., Dubbeldam, M., Wester, P. W., van den Berg, M., Vos, J. G. and Vethaak, A. D. (2007). Long-term exposure of European flounder (Platichthys flesus) to the flame-retardants tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD). Ecotoxicology and Environmental Safety (2007), Vol. 67, pp. 349-360.
Drottar et al. (2001) is the key study for this endpoint. This study was conducted in accordance with recognised testing guidelines and under conditions of GLP and was allocated a reliability score of 1 according to the criteria set out by Klimisch et al. (1997).
Ronisz et al. (2004) and Kuiper et al. (2007) , were both allocated a reliability score of 4 according to the criteria set out by Klimisch et al. (1997).

Additional information

The GLP/guideline compliant fish early life stage test in rainbow trout (Oncorhynchus mykiss) was performed at doses which were multiples of the gamma diasteromer's water solubility, e.g. eggs were exposed to nominal test concentrations of 0, 0.43, 0.85, 1.7, 3.4 and 6.8 µg/l (measured concentrations 0, 0.25, 0.47, 0.83, 1.8 and 3.7 µg/l) from 4 hours of fertilization for 88 days. At the time the study was performed, the higher water solubility of the alpha and beta isomers was not recognized. Further, the commercial product consisted of >80% of the gamma diasteromer. The LC₅₀, NOEC and LOEC were > the highest dose tested, which were based on the gamma diasteromer. Correcting for gamma diasteromer content, the NOEC was > 8.5 µg/L. Under the conditions of the test, HBCDD was not chronically toxic to rainbow trout over the 88 day exposure.

HBCDD's 28 day NOEC following intraperitoneal injection to rainbow trout was 50 mg/kg bw (Ronisz et al., 2004). The NOEC 78 day in European flounder was 800 µg/g TOC(sediment) plus 3000 µg/g lipid (food) or 8000 µg/g TOC (sediment) and 0 µg/g lipid (food).

Muscle levels corresponding to these NOEC values were up to 446 ug HBCD/g lipid weight (Kuiper et al, 2007). The dose of 8000 µg/g TOC sediment converts to 18.8 mg HBCDD/kg sediment wet weight, based on information provided in the publication. Thus, HBCDD was not chronically toxic to rainbow trout or flounder when administered at doses higher than those used in the fish early life stage test.

NOTE1: the 8000 µg/g TOC sediment was converted to mg/L to derive the NOEC in marine fish for the CSA value above.

NOTE2: the highest food dose, 3000 µg/g lipid, converts to approximately 1.3 µg/g fish bw for the first three wwwks of the test and to 2.6 µg/g fish bw for the rest of the test based on food lipid content and initial fish body weight.