ENVIRONMENTAL DEPOSITS OF DIOXINS AND FURANS (PCDD/F)

DIAGNOSTIC

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 its beginning.

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.

 

	PCDD/F 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 and furans.

	PCDD/F 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	Soils	Lichens
Target value	5	20
Food control	5 to 40	20 to 160
Cultures limited	> 40	> 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.

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 noise.

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.

BIOMONITORING

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 lichens.

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 emissions :