Reporting of Dioxins - What is Meaningful and What is not?
PCDD/Fs are an unintentional source byproduct of certain
industrial, non-industrial and natural processes, usually
involving combustion. When assessing the TRI dioxin figures
that are reported by the US EPA, it is essential to distinguish
between two numbers - the amount of PCDD/Fs that are generated
vs. the amount of PCDD/Fs that are released into the air,
water or land. Much of the PCDD/Fs that are generated is responsibly
disposed of in a sound manner and is not released into the
When compared to other EPA dioxin source inventories, the
TRI is likely to show what might appear to be high levels
of industrial PCDD/F releases. For the following reasons,
the TRI report will reflect inflated figures, not increased
- Only a small percentage of the PCDD/Fs that are released
in generated in industrial production is ever released to
the environment. This is because industry carefully treats
and disposes of the vast majority of its dioxin byproducts
in an environmentally responsible manner. These treatment
methods include disposal to specially designed hazardous
waste sites and sophisticated incineration techniques that
destroy PCDD/Fs almost completely.
- The US EPA TRI reporting format includes the figures for
both the on-site treatment and destruction of PCDD/Fs to
which the public is never exposed, as well as the smaller
amounts of this compound that are released to the environment.
This reporting requirement creates the potential for confusion
and unwarranted concern about seemingly high figures that,
in fact, do not constitute an exposure, much less a threat
to the publics well-being.
- Canada, by contrast, uses a reporting format that conveys
a more accurate picture of PCDD/Fs releases. The Canadian
reporting format provides data in toxic equivalency basis
(TEQ), a method of measurement that weights PCDD/Fs compounds
according to their toxicity. It should be noted that
TEQ is an internationally recognized method that is currently
used by the World Health Organization as a means of measuring
the toxicity of these compounds.
- The U.S. EPA Toxics Release Inventory treats all PCDD/Fs
as if they are equally toxic, which they are not. The
vast majority of all industrially produced PCDD/Fs are of
the least toxic varieties, most of which are up to 10,000-times
less toxic than 2,3,7,8-TCDD, the form of PCDD/Fs considered
to be the most toxic.
- U.S. EPA data clearly show that the chlorine chemistry
industry is not a significant source of PCDD/Fs releases
to the environment. Yet, many significant sources
of PCDD/Fs are not included in the U.S. EPAs TRI.
These unreported sources include forest fires, backyard
burning, and diesel exhausts.