THE CASEMore than thirty five years ago biologists and environmentalists were worried about the presence and accumulation of PCBs (poly chlorinated biphenyls) in the environment. Research into the effects of this group of supposedly inert chemicals led first to their use being highly restricted and then subsequently banned for most purposes.
But the use of the closely related PBBs (polybrominated biphenyls), went largely unnoticed for years. Major doubts about these, and the other brominated compounds used as fire retardants (BFRs), started to appear in the late nineties.
Brominated flame retardants (BFRs) are a group of chemicals added to many products, including computers, electrical equipment, furnishing fabrics and carpets, in order to reduce fire risk. The most suspect BFRs are the PBBs, the polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol a (TBBP-A).
In 2004 an article "Brominated Flame Retardants: Cause for Concern?" appeared in the journal Environmental Health Perspectives (Volume 112, Number 1, January 2004). The conclusion was that not enough was known about these compounds and that detected biological accumulation is sometimes inconsistent with the measured environmental half-lives. This means that just measuring environmental levels of these chemicals is not a satisfactory measure of the actual environmental effects.
There is a substantial amount of research into BFRs in humans, for example Food Standards Australia and New Zealand released the "FSANZ study of brominated flame retardants in food" in December 2007. They found that levels of BFRs in Australian foods were comparable to those in other countries.
The Australian Government has also released a fact-sheet "Polybrominated diphenyl ether flame retardants (PBDEs)" that outlines concerns and gives advice about the PBDEs. This is largely based on another report "Interim Public Health Risk Assessment of Certain PBDE congeners". This latter report briefly analyses the known health risks associated with PBDEs, including the induction of liver enzymes, effects of thyroid function, developmental changes and reproductive effects.
It is an entirely rational assumption that effects detected in one mammalian species (for example human beings) will also be seen in others. The authors of "A Study of the Presence of Brominated Flame Retardants in Australian Fauna" detected PBFs in Sperm Whales, Altantic Salmon, various raptors and Tasmanian Devils.
How on earth do compounds that start out in carpets and computers end up in Sperm Whales and Tasmanian Devils? Why is the concentration of PBFs in some devils so much higher than in others?
The population of Tasmanian Devils has been decimated by a transmissible cancer the Tasmanian Devil Facial Tumour Disease (DFTD). Most devils seem to be immunologically unable to resist this tumour. The question is are these two things linked. Is the devil's immune system being compromised by the environmental BFRs? Is there any correlation between the devil's PBF level and susceptibility to DFTD?
This is certainly a possibility, as it is known that these compounds may interfere with the function of all steroid hormones, anabolic, sex hormones and the adrenocorticoids. See:
Effects of Polybrominated Biphenyls (PBB) on Immune Response in Rodents Michael I. Luster, Robert E. Faith, John A. Moore Environmental Health Perspectives, Vol. 23, Apr., 1978 (Apr., 1978), pp. 227-232 doi:10.2307/3428765
"These studies indicate that PBB exposure can lead to suppression of both humoral and particularly cell-mediated immune responses."
In other words the ability to fight infections and cancers.
MY VERDICT
The sooner the Brominated flame retardants (BFRs) are removed from the market, the better, both from a human and a wildlife point of view.
UPDATE (19/03/2008)
A report has just been handed to the Tasmanian Government, demonstrating that there is no link between the tissue level of chemicals and the presence of DFTD in devils. The study compared 22 healthy devils with 23 diseased animals. The study noted that there was no detectable 1080, but that the arsenic levels warranted further investigation.
This report in no way removes the need to discontinue the use of brominated flame retardants.
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