ENVIRONMENTAL DEPOSITS OF DIOXINS
AND FURANS (PCDD/F)
Aair Lichens, who created this technique during
the 2000 year, is the only one able to use it (trademark Li-Diox®).
Considered as operational, near as 200 measures were realized since
The technique was recently underlined by representatives
to the French Environment Ministry.
The dosages of dioxins and furans in lichens are practiced according
to a precise mode of sampling.
in Air and Lichens
The qualitative profile of the
17 compounds PCDD / F used for the calculation of the I-TEQ
(Index Toxic Equivalent) is identical in lichens and air.
Any measure in lichens reports atmospheric transfers of dioxins
in soils and lichens
The comparison with measures practiced
in soils shows a bigger sensibility of lichens (multiplied
by four) and allows the link with recommendations, and the
acceptance of a target value.
Reminder of the German recommendations for soils.
REMINDER OH THE
GERMAN RECOMMENDATIONS FOR SOILS
Results : ng I-TEQ/kg
5 to 40
20 to 160
The geographic references of the dosages
allow drawing up maps showing the intensity of environmental deposits
and their surface. They are estimated and integrated into a comparison
interpretation against the background noise and in a target value.
Non significant values
Significant values lower than the
target value of 20 ng I-TEQ/kg
Ring 1 : from 6 to 8 I-TEQ
Ring 2 : from 5 to 6 I-TEQ
Ring 3 : from 3,5 to 5 I-TEQ
The local background noise is, either measured
by a sampling at distance of the source, or by a calculation from
the obtained data. The significant values, that are giving evidence
of environmental fall-out, must be higher than 40 % to the background
This interpretation allows mapping the significant
deposits. The comparison with the target-value (20 ng I-TEQ / KG)
allows to differentiate what is a sign of activity and what needs
recommendations for the local residents.
This example, abstract from an
Aair Lichen study, shows results with significant values situated
under the target value.
This deposit does not need recommendations
for neighbourhood but only an annual biomonitoring using lichens.
The first works of biomonitoring show that
lichens have a capacity of keeping back of the PCDD/F which links
the average level of the atmospheric contents into pollutants independently
of the scarse peaks.
In less than two years after upgrade to standards the PCDD/F contents
in lichens samples can decrease by a factor superior for four.
Repeated biomonitoring shows that lichens
maintain equilibrium with the surrounding air. As PCDD/f content
in the surrounding air decreases, so dose the PCDD/f content in
It is well-to-do the technique Li-Diox®
in urban areas because it is frequently the only one able to follow
the environmental deposits.
Biomonitoring example after an improving of
Three significant values.
the target value.