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LICHENOLOGY

THE LICHENS
Lichens are organisms with two live components: a tiny fungus and a unicellular alga (or cyanobacteria). Such a symbiosis is responsible for certain peculiarities used for monitoring the air quality.


Effectively, lichens do not underact with the bearing substratum, especially because they do not have roots and they are totally dependent on the air for their nutrition. They have a continuous growth, lack resistance in the hydric stress and cannot react to the modifications of the Air Quality.		  


 


Therefore, all substances and particles contacting their surface penetrate inside and are trapped by a network of fungi filaments.

According to these peculiarities, two categories of techniques are used to perform environmental diagnostics

THE PROCESS

Both techniques are based on field work with natural biocaptors called lichens (mainly those lichens which grow on tree bark :

1 - Flora studies (bioindication)

2 - Analysis (bioaccumulation or biokeeping back).

The Aair Lichens Company accompanies his institutional and industrial customers during the presentation of the results to the representatives of the state and to the local elected members. We participate in the reports of the studies during the Local Committees.

FLORA STUDIES (BIOINDICATION)


In optimal ecological conditions, lichens live and reproduce with a state of balance and numerous sorts constitute a lichenic community.

The variations of the composition of the lichenic flora under the influence of the Air Quality at the human level represent the base of the lichenic flora studies. Indeed, the atmospheric pollutions lead a selection of species, the most sensitive disappear while the resistant stabilize or proliferate according to the nature of the concerned pollutant. These peculiarities authorize the use of the inventory of lichens species with the aim to represent the surfaces where the Air Quality is modified or, on the contrary, excellent.

The geographic references allow drawing up maps of modeling by connecting the results and the geographic coordinates. It is then possible to spatialise the Air Quality on maps. Sensitive or protected zones are shown and the Air Quality can be follow by the lichenic flora study.

From initial studies, a selection of representative plots allows to realize a biomonitoring.

 

ANALYSIS (BIOACCUMULATION OR BIOKEEPING BACK)


The lichens physiology and constitution, their absence of protection towards trace elements pollutants make them able to accumulate or temporarily retain more than 50 trace-elements, heavy metals or organic molecules such as Polycyclic Aromatic Hydrocarbons, pesticides, and dioxins and furans.

The use of lichens allows to spatialise the fall-out of pollutants and their intensity. The taking of populations of lichens, collected according to a rigorous protocol on vertical supports is subjected after preparation to dosages confided to guaranteed and approved laboratories.

• We use these techniques regularly for the industry, Local governments and the General councils.

• From initial studies, a selection of representative sectors is used to realize an annual or biennial biosurveillance.

conception/realisation IDcoder