Research progress on HBCD

Progress in toxic and cumulative metabolism of hexabromocyclododecane Hexabromocyclododecane, the third largest brominated flame retardant in the world, is currently under review by the Stockholm Convention Committee of Experts as a persistent organic pollutant (POPs) One of three chemicals. Commercial grade HBCD contains mainly three isomers a-, b- and g-HBCD, with the highest g-HBCD content (70%-85%), each of which contains two chiral pairs. The body.

The Research Group on Urban Water Environmental Process and Ecological Risk Assessment of the Institute of Urban Environment, Chinese Academy of Sciences conducted a-, b- and g-HBCD studies on the developmental toxicity and cumulative metabolism of zebrafish. The study found that the three isoforms can prolong the incubation time of zebrafish embryos, inhibit embryonic heartbeat, inhibit growth, and cause developmental malformations under high concentration conditions. The toxicity is in the order of g-HBCD>b-HBCD>a. -HBCD; a-, b- and g-HBCD have different bioaccumulation rates and metabolic rates in zebrafish. The absorption efficiency, biomagnification factor and half-life of a-HBCD are highest among the three isomers; (-) a-HBCD and (-) g-HBCD, (+) a-HBCD and (+) g-HBCD more easily accumulate in zebrafish.

The study also found that g-HBCD can be bio-isomerized in zebrafish and converted to a-HBCD. The results of this study provide a scientific explanation for the fact that HBCD is predominantly a-HBCD in organisms in nature. in accordance with. In addition, the metabolite monohydroxydibromocyclododecadiene, which has not been found in the body of zebrafish, was found. These findings provide a scientific basis for the environmental management of HBCDs.