Re: dioxin/cl/incineration: another study

[lshadoff@brazosport.cc.tx.us (Lewis A. Shadoff)]

I don't understand something about this study's conclusion.


>   Total annual US air emissions of polychlorinated dibenzo-p-
>dioxins and polychlorinated dibenzo-furans (PCDD/F) from all
>known sources are estimated to be about 400 kilograms as of
>1989, almost entirely from combustion sources.  Municipal
>solid waste incineration is the largest known source of
>PCDD/Fs, as of 1989.  The next largest sources include
>   hospital waste incineration, forest and agricultural fires,
>and residential wood burning

>   4.  DIOXIN EMISSION SOURCES
>   4.1  Consumer Waste Incineration.
>   Municipal waste incineration:  In 1989, about 20 million tons
>  of municipal solid waste (MSW), 15% of the total, were
>   incinerated in the US.
>    ... The average emission factor, weighted for the amount of
> waste combusted at each type of facility, is, to one
>   significant figure, 10 ug/kg.
>

I calculate a total d/f emission of 180 kg/yr from the above.

>
>   4.2  Industrial Waste Processing and Incineration
>   Hazardous waste incineration:  ... As of 1989, about 1.6
>million tons of hazardous waste was burned at commercial and
>private hazardous waste incinerators in the US, and about 2
>million tons at cement and aggregate kilns, boilers and other
>furnaces (Table 5).

>
>   Although it may be a substantial overestimate, total dioxin
>emissions from hazardous waste combustion will be estimated
>using the average emission factor from each subcategory.  This
>results in an overall emission estimate, to one significant
>figure, of 10 kg annually.

I get 7 kg/yr from the average production rates.

The total is 190 kg/yr for municipal and industrial waste incineration.

There are no other calculatable totals from what was posted since the total
number of tons was not given.  However, if municipal incineration is the
major source at 180 kg/yr, industrial incineration next at 10 kg/yr, how
can the total be 400 kg/yr?  Does the paper give the figures?



Lewis A. Shadoff BS, PhD, Lake Jackson, Texas