Bioavailability of hexabromocyclododecane (HBCD) in rats from dust and oil vehicles

Authors: Lupton, Sara; Pfaff, Colleen; Singh, Anuradha; CHAKRABARTY, SHUBHASHIS - North Dakota State University; HAKK, HELDUR - Retired ARS Employee

Submitted to: Environmental Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2022
Publication Date: 11/17/2022
Citation: Lupton, S.J., Pfaff, C.M., Singh, A., Chakrabarty, S., Hakk, H. 2022. Bioavailability of hexabromocyclododecane (HBCD) in rats from dust and oil vehicles. Environmental Research. 218. Article 114853. https://doi.org/10.1016/j.envres.2022.114853.
DOI: https://doi.org/10.1016/j.envres.2022.114853

Interpretive Summary: Hexabromocyclododecane (HBCD) was used as flame retardant in household products for decades in the United States. Household dust is an important source of HBCD exposure in humans, and especially in children who are exposed to more dust on a daily basis than adults. Experiments were conducted to determine the bioaccumulation of HBCD in rats after a 21-day exposure to diets fortified with household dust containing known amounts of HBCD. HBCD residues accumulated to a much greater extent in fatty tissues of rats than in livers or muscle. The study suggests that HBCD is bioavailable from dust and that HBCD accumulation is not similar for all tissues. These data will help risk assessors determine the overall risks to humans from environmental and dietary sources of HBCD.

Technical Abstract: Hexabromocyclododecane (HBCD) is a brominated flame retardant (BFR) labeled by the Stockholm Convention as a persistent organic pollutant (POP). One of the major routes of human exposure to HBCD is dust found in homes, offices, and cars and dust may be the most important route of HBCD exposure in young children. A study was conducted to determine the oral bioavailability of HBCD from household dust in rats over 21-d feeding period relative to HBCD bioavailability from a vegetable oil matrix. Twenty-four hours after the last exposure, rats were sacrificed, and various tissues were collected. HBCD diastereomers were detected in adipose, blood, and liver of both dose groups, suggesting HBCD is bioavailable from both oil and dust. ß-HBCD concentrations were below the limit of detection in all tissues, but a-HBCD was detected in the brain of oil-dose rats and in adipose and liver of both dose groups. '-HBCD was the dominant diastereomer in adipose, blood, and liver samples regardless of dosing matrix. Except for '-HBCD in muscle of the oil-dosed group, muscle did not contain measurable HBCDs. Adipose tissue accumulated HBCD to a greater extent than muscle or liver, having bioconcentration factors greater than 1.