Intake fraction for dioxin emission in Hämeenkyrö
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Scope
Intake fraction for dioxin emission in Hämeenkyrö. Emission from a high stack in Hämeenkyrö, exposed population anywhere in Europe. Long-term exposure, includes accumulation in food chain. 'Dioxin' means TEQs of all 17 toxic congeners, not only TCDD.
Description
Intake fraction (iF) means the fraction of an emission that is finally inhaled or ingested by a target population. The exposure to dioxins occur after a multistep process. First, dioxins are emitted into the atmosphere often due to a combustion process. Dioxins are persistent molecules and can transfer hundreds or thousands of kilometres before depositing to water, vegetation, or soil. It absorbs tightly onto surfaces, and therefore it is rather inert if adsorbed to soil. However, when dioxins deposit to water, they enter the aquatic food chain and end up to fish. When they deposit on grass fields or crop, they typically enter the cattle feed and then milk or meat. Because of this long process including accumulation in food chain, the dioxin exposure of a population is mostly derived from other than local sources.
Margni and coworkers have estimated an iF for Western European sources. The iF is approximately 3.5*10-3 for emissions of dioxin in Western Europe. This iF compares well to the traditional non-spatial multi-media/-pathway model predictions of 3.9*10-3 for the same region and to 2*10-3 for the USA. Approximately 95% of the intake from Western European emissions occurs within the same region, 5% being transferred out of the region in terms of food contaminants and atmospheric advective transport. (Margni et al., 2004) However, when the emission source is in the North-Eastern corner of Europe like Hämeenkyrö is, the population exposed is likely smaller than on average, especially because the predominant wind direction is from southwest and away from densely populated areas. Therefore, the published value is likely an overestimate.
References
- Margni M, Pennington DW, Amman C, Jolliet O. Evaluating multimedia/multipathway model intake fraction estimates using POP emission and monitoring data. Environ Pollut. 2004;128(1-2):263-77.
- Bennett DH, Margni MD, McKone TE, Jolliet O. Intake fraction for multimedia pollutants: a tool for life cycle analysis and comparative risk assessment. Risk Anal. 2002 Oct;22(5):905-18.
Definition
Comes from literature (Margni et al., 2004).
Unit
- (dimensionless)
Result
3.5*10-3