The Challenge: The use of flame retardants (FRs) as additives in a variety of consumer use products, including plastics, textiles, and electronics, is projected to continue and increase for the foreseeable future. Because of unanticipated environmental problems, some FRs have either been banned, restricted, or are being phased-out and replaced by other new and presumably safer FRs. Regrettably, many of these alternative FRs are found to bioaccumulate in wildlife tissues, including in bird eggs, suggesting exposure through maternal deposition. However, few data are available on the potential adverse effects in exposed animals.
The Science:In collaboration with Environment and Climate Change Canada, USGS biologists from Patuxent Wildlife Research Center (PWRC) are investigating the effects of embryonic exposure to alternative FRs in birds. These studies employ avian egg injection methods developed at PWRC to simulate maternal deposition of pollutants. Studies to date, have examined the effects of four brominated FR (BFR) - tetrabromobisphenol A bis[2,3-dibromopropyl ether] (TBBPA-BDBPE), 2-ethylhexyl- 2,3,4,5-tetrabromobenzoate (EHTBB), bis(2-ethylhexyl)-2,3,4,5- tetrabromophthalate (TBPH), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). These additive FRs are used in plastic products, resins, textiles, paints, and household electronics as replacements for the phased-out decabromodiphenyl ether (decaBDE), pentaBDE or OctaBDE FRs. Using American kestrel (Falco sparverius), a semi-altricial raptorial model, we examined the potential toxicity of these FRs on survival, growth, molecular, biochemical, histological and endocrine endpoints. Transcriptome sequencing (RNAseq) and digital gene expression are being used to identify affected pathways in the birds.
The Future: These studies will help determine the potential hazards posed by BFRs to free-ranging birds, providing critical data needed for understanding commonalities and differences in their modes of action. Findings will address the relationship between effects at lower levels of biological organization (e.g. molecular) and adverse effects at the individual, population or higher levels that are relevant to risk assessment and natural resource management.
Below are publications associated with this project.
In ovo exposure to brominated flame retardants Part I: Assessment of effects of TBBPA-BDBPE on survival, morphometric and physiological endpoints in zebra finches
In ovo exposure to brominated flame retardants Part II: Assessment of effects of TBBPA-BDBPE and BTBPE on hatching success, morphometric and physiological endpoints in American kestrels
Sex‐specific responses in neuroanatomy of hatchling American kestrels in response to embryonic exposure to the flame retardants bis(2‐ethylhexyl)‐2,3,4,5‐tetrabromophthalate and 2‐ethylhexyl‐2,3,4,5‐tetrabromobenzoate
Female hatchling American kestrels have a larger hippocampus than males: A link with sexual size dimorphism?
Below are partners associated with this project.
- Overview
The Challenge: The use of flame retardants (FRs) as additives in a variety of consumer use products, including plastics, textiles, and electronics, is projected to continue and increase for the foreseeable future. Because of unanticipated environmental problems, some FRs have either been banned, restricted, or are being phased-out and replaced by other new and presumably safer FRs. Regrettably, many of these alternative FRs are found to bioaccumulate in wildlife tissues, including in bird eggs, suggesting exposure through maternal deposition. However, few data are available on the potential adverse effects in exposed animals.
The Science:In collaboration with Environment and Climate Change Canada, USGS biologists from Patuxent Wildlife Research Center (PWRC) are investigating the effects of embryonic exposure to alternative FRs in birds. These studies employ avian egg injection methods developed at PWRC to simulate maternal deposition of pollutants. Studies to date, have examined the effects of four brominated FR (BFR) - tetrabromobisphenol A bis[2,3-dibromopropyl ether] (TBBPA-BDBPE), 2-ethylhexyl- 2,3,4,5-tetrabromobenzoate (EHTBB), bis(2-ethylhexyl)-2,3,4,5- tetrabromophthalate (TBPH), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). These additive FRs are used in plastic products, resins, textiles, paints, and household electronics as replacements for the phased-out decabromodiphenyl ether (decaBDE), pentaBDE or OctaBDE FRs. Using American kestrel (Falco sparverius), a semi-altricial raptorial model, we examined the potential toxicity of these FRs on survival, growth, molecular, biochemical, histological and endocrine endpoints. Transcriptome sequencing (RNAseq) and digital gene expression are being used to identify affected pathways in the birds.
The Future: These studies will help determine the potential hazards posed by BFRs to free-ranging birds, providing critical data needed for understanding commonalities and differences in their modes of action. Findings will address the relationship between effects at lower levels of biological organization (e.g. molecular) and adverse effects at the individual, population or higher levels that are relevant to risk assessment and natural resource management.
- Publications
Below are publications associated with this project.
In ovo exposure to brominated flame retardants Part I: Assessment of effects of TBBPA-BDBPE on survival, morphometric and physiological endpoints in zebra finches
Tetrabromobisphenol A bis(2,3-dibromopropyl) ether (TBBPA-BDBPE) is an additive flame retardant used in polyolefins and polymers. It has been detected in biota, including in avian eggs, yet little is known of its effects. We assessed the pattern of TBBPA-BDBPE concentrations in songbird eggs over the incubation period, and the effects of embryonic exposure to TBBPA-BDBPE in a model songbird specieAuthorsMargaret Eng, Tony D. Williams, Kim J. Fernie, Natalie K. Karouna-Renier, Paula F. P. Henry, Robert J. Letcher, John E. ElliottIn ovo exposure to brominated flame retardants Part II: Assessment of effects of TBBPA-BDBPE and BTBPE on hatching success, morphometric and physiological endpoints in American kestrels
Tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTPBE) are both brominated flame retardants (BFRs) that have been detected in birds; however, their potential biological effects are largely unknown. We assessed the effects of embryonic exposure to TBBPA-BDBPE and BTBPE in a model avian predator, the American kestrel (Falco sparverius). FertAuthorsMargaret Eng, Natalie K. Karouna-Renier, Paula F. P. Henry, Robert J. Letcher, Sandra L. Schultz, Thomas G. Bean, Lisa E. Peters, Vince P. Palace, Tony D. Williams, John E. Elliott, Kim J. FernieSex‐specific responses in neuroanatomy of hatchling American kestrels in response to embryonic exposure to the flame retardants bis(2‐ethylhexyl)‐2,3,4,5‐tetrabromophthalate and 2‐ethylhexyl‐2,3,4,5‐tetrabromobenzoate
Bis(2‐ethylhexyl)‐2,3,4,5‐tetrabromophthalate (BEH‐TEBP) and 2‐ethylhexyl‐2,3,4,5‐tetrabromobenzoate (EH‐TBB), flame retardant components of FireMaster 550® and 600® have been detected in tissues of wild birds. To address the paucity of information regarding potential impacts of flame retardants on the brain, brain volume regions of hatchling American kestrels (Falco sparverius) were evaluated folAuthorsMélanie F. Guigueno, Natalie K. Karouna-Renier, Paula F. P. Henry, Lisa E. Peters, Vince P. Palace, Robert J. Letcher, Kim J. FernieFemale hatchling American kestrels have a larger hippocampus than males: A link with sexual size dimorphism?
The brain and underlying cognition may vary adaptively according to an organism’s ecology. As with all raptor species, adult American kestrels (Falco sparverius) are sexually dimorphic with females being larger than males. Related to this sexual dimorphism, kestrels display sex differences in hunting and migration, with females ranging more widely than males, suggesting possible sex differences inAuthorsMelanie F. Guigueno, Natalie K. Karouna-Renier, Paula F. P. Henry, Jessica A. Head, Lisa E. Peters, Vince P. Palace, Robert J. Letcher, Kimberly J. Fernie - Partners
Below are partners associated with this project.