Toxic Chemical Pollution: 2001
P.O., Eriksen, G.S., Johannesson, T., Larsen, P.B., and Viluksela, M.
ethers: Occurrence, dietary exposure, and toxicology.
Health Perspectives 109: 49-68, 2001.
© National Institute of Environmetal Health
diphenyl ethers (PBDEs) are used as flame retardants in plastics (concentration,
5-30%) and in textile coatings. Commercial products consist predominantly
of penta-, octa-, and decabromodiphenyl ether mixtures, and global PBDE production
is about 40,000 tons per year. PBDEs are bioaccumulated and biomagnified in
the environment, and comparatively high levels are often found in aquatic
biotopes from different parts of the world. During the mid-1970-1980s there
was a substantial increase in the PBDE levels with time in both sediments
and aquatic biota, whereas the latest Swedish data (pike and guillemot egg)
may indicate that levels are at steady state or are decreasing. However, exponentially
increasing PBDE levels have been observed in mother's milk during 1972-1997.
Based on levels in food from 1999, the dietary intake of PBDE in Sweden has
been estimated to be 0.05 mug per day. Characteristic end points of animal
toxicity are hepatotoxicity, embryotoxicity, and thyroid effects as well as
maternal toxicity during gestation. Recently, behavioral effects have been
observed in mice on administration of PBDEs during a critical period after
birth. Based on the critical effects reported in available studies, we consider
the lowest-observed-adverse-effect level (LOAEL) value of the PBDE group to
be 1 mg/kg/day (primarily based on effects of pentaBDEs). In conclusion, with
the scientific knowledge of today and based on Nordic intake data, the possible
consumer health risk from PBDEs appears limited, as a factor of over 10(6)
separates the estimated present mean dietary intake from the suggested LOAEL
value. However, the presence of many and important data gaps, including those
in carcinogenicity, reproduction, and developmental toxicity, as well as additional
routes of exposure, make this conclusion only preliminary. Moreover, the time
trend of PBDEs in human breast milk is alarming for the future.