Why do we still care about dioxins?
- Indiana Univ., Bloomington, IN (United States)
Chlorinated dioxins and dibenzofurans (PCDD/F) are well-known environmental contaminants that have received prolonged attention by the scientific community and by environmental regulators. They enter the atmosphere primarily as byproducts from industrial combustion, waste incineration, metals production, and automobile emissions. PCDD/F are semivolatile, hydrophobic compounds; hence they accumulate in organic rich media such as soils, sediments, and biota. In spite of knowledge about the environmental behavior of PCDD/F, a significant problem remains: Deposition from the atmosphere is estimated to be roughly 10-25 times higher than estimated inputs from known sources. There are three explanations for this mass balance discrepancy: (a) The depositional fluxes are overestimated because of sampling bias. (b) The input estimates are low because of unrecognized sources. (c) Both the sources are underestimated and the deposition is overestimated. The authors believe that depositional fluxes are overestimated because most PCDD/F measurements have been made in places of significant human industrial activity. Clearly, an expanded database of PCDD/F measurements from many geographical regions must be established before a realistic assessment of their mass balance can be made.
- OSTI ID:
- 210709
- Report Number(s):
- CONF-9505261--
- Country of Publication:
- United States
- Language:
- English
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