MadSci Network: Chemistry
Query:

Re: How/Are dioxins released from plastic?

Date: Mon Oct 20 10:13:52 2003
Posted By: Tony Gaglierd, Assistant Professor , Natural Science and Engineering Technology
Area of science: Chemistry
ID: 1066174423.Ch
Message:

Hi Travis. You need to know how dioxins are released from plastic.

Although all of the sources or processes that contribute to Chlorinated 
dioxins in the environment have not been identified, Chlorinated dioxins 
are known to be formed in the manufacture of chlorinated organic chemicals 
and pesticides, during smelting of metals, in the incineration of 
municipal, medical, and industrial wastes, and from the production of 
bleached wood pulp and paper.

Chlorinated dioxins are also found in emissions from the combustion of 
various other sources, including coal-fired or oil fired power plants, 
wood burning, and home heating systems.

Chlorinated dioxins also occur in other combustion products (e.g., 
cigarette smoke), automobile exhaust from cars running on leaded gasoline 
with chlorine scavengers and to a lesser extent from cars running on 
unleaded gasoline, and diesel exhaust.

Chlorinated dioxins can form during the synthesis and combustion of 
chlorine-containing materials, such as polyvinyl chloride (PVC),

Chlorinated dioxins occur as contaminants in the manufacture of various 
pesticides and, as a result, have been released to the environment during 
use of these pesticides. 

The historical increase in Chlorinated dioxins, suggesting that 
accumulation of these compounds in the environment is a recent phenomenon 
related to the production, use, and subsequent incineration of chlorinated 
organic chemicals.

Chlorinated dioxins strongly adsorb to soils and sediments. Due to their 
low vapor pressure and low aqueous solubility and their strong sorption to 
particulates, Chlorinated dioxins are generally immobile in soils and 
sediments.

In my research I could not find any reference to release of dioxins from 
plastics exposed to microwave energy. 

As fare as their release from landfills as you can see from the above 
paragraph dioxins are strongly attracted to soils and have low vapor 
pressure thus they are generally immobile in soils.

PCBs on the other hand have been shown to be released from contaminated 
soils in landfills and hazardous waste sites; deposition of vehicular 
emissions near roadway soil; and land application of sewage sledges 
containing PCBs.

It has been suggested that certain electrical appliances and devices 
(e.g., fluorescent lighting ballasts) and building materials (elastic 
sealant), which have PCB-containing components, may emit PCBs into the 
indoor air, thereby elevating indoor PCB levels significantly above 
outdoor background levels.

I hope I have answered you question. Good luck on you science project.

For more information see the following sites:
 http://www.atsdr.cdc.gov/toxpro2.html - Dioxin 



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