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Bioaccumulation of bis-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate and mono-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate by Lumbriculus variegatus
Citation:
Burkhard, L., T. Lahren, T. Highland, R. Hockett, Dave Mount, AND T. Norberg-King. Bioaccumulation of bis-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate and mono-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate by Lumbriculus variegatus. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, 80:579–586, (2021). https://doi.org/10.1007/s00244-021-00824-4
Impact/Purpose:
Numerous brominated flame-retardants are used in commerce for decreasing risks associated with fires. One of the brominated flame retardants is bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) and within the United States, its production volume in 2012 ranged between 1 and 10 million pounds. TBPH is component of flame retardants formulations such as Firemaster® products (i.e., 550, 600, BZ-54) and DP-45, and is often used to treat polyurethane foam used in furniture. Resultantly, TBPH has been found across the globe in indoor and outdoor dust. The ultimate environmental sink besides landfills for TBPH is soils and sediments, and numerous investigators have detected and quantified the levels of TBPH in soils and sediments. Once in the sediments, TBPH may bioaccumulate in aquatic organisms, and potentially present risks to wildlife and humans that consume them. Information on the bioaccumulation of TBPH is limited, and the focus of this effort was to determine the bioaccumulation potential of TBPH from sediments by Lumbriculus variegatus. We also investigated the bioaccumulation of mono-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBMEPH), TBPH with of one of its ester groups removed. TBMEPH is a potential biotransformation product of TBPH and by including this chemical in the study, we could evaluate the rate of biotransformation of TBPH to TBMEPH by L. variegatus. Audience TBPH is very hydrophobic organic chemical with a measured log KOW of 9.21. EPA’s Office of Chemical Safety and Pollution Prevention (OCSPP) is interested in data for very hydrophobic chemicals in order to improve assessments of risk for new chemicals with similar properties. Further, given its production volume, having measured physical-chemical properties and knowledge of its bioaccumulation potential, allows OCSPP to better assess its uses and risks. Impact Data from this effort will enable models for predicting the bioaccumulation of very hydrophobic chemicals to be improved. Currently, there are large uncertainties associated with bioaccumulation predictions for high hydrophobic chemicals, and having measurements, enables these improvements. OCSPP will also have measurements on this chemical when and if it decides to re-evaluate the registration of products containing TBPH.
Description:
The brominated flame retardant bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) is used widely in consumer items including polyurethane foam used in furniture. Information on its bioaccumulation in aquatic species is limited and in the current study, sediment bioaccumulation tests with the oligochaete Lumbriculus variegatus were performed on a spiked natural sediment equilibrated for 14.5 months. Analysis showed the TBPH used to spike the sediment contained a small amount (0.046% by mass) of mono-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBMEHP), a potential biotransformation product of the parent chemical. Steady-state biota-sediment accumulation factors (BSAFs) of 0.254 and 1.50 (kg organic carb/kg lipid) were derived for TBPH and TBMEHP, respectively. TBPH had biphasic elimination behavior where 94% percent of the body burden was eliminated within the first 12 hours of elimination (half-life of 1.2 hours or less), and the remaining 6% eliminated very slowly thereafter (half-life of 15 days). There was little evidence for biotransformation of either chemical by L. variegatus.
URLs/Downloads:
DOI: Bioaccumulation of bis-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate and mono-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate by Lumbriculus variegatus