Re: dioxins cigarette smoking/EPA's draft inventory

["Alex J. Sagady & Associates" <ajs@sagady.com>]

The issue really isn't how much cigarettes contribute to 
outdoor ambient concentrations of PCDD/PCDF.   The 
public health issue is whether cigarettes indeed produce
PCDD/PCDF in direct stream and sidestream smoke, and 
subsequent human exposure from those pathways in 
smokers and from others exposed indoors to sidestream
smoke.

It wouldn't take very much PCDD/PCDF production in
cigarettes (if this has been measured in direct stream and
sidestream smoke) for subsequent direct stream and sidestream
exposures to drarf all other types of exposures because there
is virtually no dilution for direct stream smoke and little for 
indoor sidestream exposure.

I'd like to see the exposure assessment for direct stream and 
sidestream cigarette smoke exposure to PCDD/PCDF, if one exists....


At 02:21 AM 08/16/1999 -0400, you wrote:
>>At a recent seminar on dioxins a Public Health Official, in trying to avert
>>attention from the high dioxin emissions from the local sinter plant,
>>stated that cigarette smoking also produced dioxins. It was claimed that 20
>>cigarettes could expose a person with 4.3 pg/kg/day.
>>How correct is this and is there a scientific paper to back it up ?
>>Thanks for your help and I apologize if this subject has been discussed
before.
>>
>>Yoke Berry
>>Wollongong
>>Australia
>---
>
>EPA/ORD's '4/98 External Review Draft (sensitively printed on Unity DP's
>unbleached paper) of "The Inventory of Sources of Dioxins in the U.S.' is
>relatively thorough, including estimates of releases in products; and it's
>discussion is direct, simple & thorough.  For example, it ranks and
>discusses the estimates by confidence of accuracy, so while it is very
>thorough in discussing and summarizing available source info for many
>categories, it refrains from including many important ones in the actual
>draft emissions inventory.  E.g:  backyard trash burning & l. fill fires (1
>kg/yr, high uncertainty estimate) (TEq basis, incl coplanar PCBs, to be
>consistent w/ their political hostage, the draft dioxin risk
>(re)assessment).  Source emissions are estimated for '87 and '95.  It does
>make the seemingly valid point that large, (combustion, presumably)
>emissions sources may be quite far from the nation's food supply (ie fields
>turned into feed for the animals you eat), so it cannot be assumed the
>largest sources are the largest contributors to human body burdens.
>
>It's outrageous they refuse to estimate EDC/VC dioxin releases, given that
>there is enoough data (thanks in part to GPeace) now to at least give a
>"highly uncertain" estimate.  Given that EPA has requested this type of
>chemical data from industries hundreds of times over the years, I have
>little doubt it's political.  Bldg fires, PCB combustion, petroleum
>catalyst regeneration (a huge source, as I understand it), and scrap wire
>regenration (burning off PVC coated copper wire--Cu is the ideal catalyst
>for dioxin formation), PCP treated wood emissions (though PCP manufacture
>is listed as far and away (89.9%) the largest source of dioxins (TEq basis)
>in the USA, the releases from the wood it's used to treat (and intermediary
>steps) aren't estimated (tho obviously exposure isn't near as great as
>combustion sources)), and finally, reservoir sources--all these and some
>others too, EPA begs-off with  "insufficient data to make an estimate".
>Yet when thy do put an estimate in the inventory, the confidence can be as
>low as a 10-fold spread in the number given.
>
>Anyway, whether a source is in the draft inventory or not with an estimate,
>the data summarized for all sources tends to be quite thorough, w/ useful
>graphs & summary tables.  So, hopefully by the time it's finalized, a lot
>more  of these critical estimates will be in place.  Note that EPA has an
>Emissions Inventory Improvement Program (EIIP, in which it recognizes that
>emission factors (concentrations) and inventories (mass amnts) are
>generally always biased low--due to industry supplied data, data taken
>during ideal stack test conditions, etc. etc.)  This is a massive problem
>that makes something of a joke of everything EPA does in air pollution, as
>EI & EF are used in almost every rule and permit in the country.  Of
>course, dioxin emisison inventory data is based on an even wider range of
>data quality...
>
>So, for ciggies, they use several studies, and overall emissions of
>0.25-2.5g (median 0.81g)/yr are averaged from 2 models, the low one
>assuming no dioxins are formed during combustion (based on a large analysis
>of dioxin content unburned).  During a drag, T's go from 900d.C to
>200-400d.C 2 mm past the char line--this is an ideal dioxin formation T
>drop, but EPA doesn't say that.  Confidence is high for the amnts of
>tobacky burned, but low for the emission factor.  Nonetheless, typically, a
>good deal of EF data is summarized.  EF's for burned ciggies had similar
>congener profiles, but varied > 1 order magnitude, 0.09 - 0.9
>pg/cigarrette.  In the large, unburned study, 109 -1,136 pg/*pack*, w/ the
>low # coming from one Chinese brand (possibly unbleached paper?).  As
>apparantly the congener profile in this & in one other small uburned study
>is similar to the profiles when burned, EPA believes it valid to average
>both models together (as above) for its inventory estimate.  Also given the
>moisture that collects behind the char line, and the large # of compounds
>known to be moved by a water distilation process from the tobacco into the
>smoke in this unburned area, EPA again believes its plausible to assume
>some of the inhaled dioxins are from unburned tobbacky.  But presumably
>there's a lot of chlorine in the bleached paper not subject to this
>distilation into the smoke stream, that instead is burned, liberated, and
>converted into dioxins when the T drops (as they always are formed during
>combustion).
>
>Tony Tweedale
>
>Causality is a concept not subject to empirical demonstration. -David Hume
>(1711-'76)
>
>Temperate but endangered planet.  Enjoys weather, northern lights,
>continental drift.  Seeks caring relationship with intelligent life form.
>      -Friends of the Earth
>
>
>
>
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