C - Lublin
C - Lublin
C - Lublin
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OUTPUT FLUXES OF LEAD IN FOREST ECOSYSTEMS:<br />
SOME APPROACHES TO CALCULATING AND MAPPING<br />
Priputina I., Mikhailov A., Abramychev A.<br />
The input of heavy metals (HM) to terrestrial ecosystems is well known to be a<br />
large scale environmental problem. Aerial deposition because of industrial<br />
emissions is the dominant input of metals to forest ecosystems that can be resulted<br />
in increasing of HM concentrations in the soils as well as in plants and ground<br />
waters. Indications of adverse effects on biota dealt with high levels of metal<br />
accumulation in forest soils are found in many areas in Europe (Curlik et al., 2000).<br />
The methods of calculating of permissible levels of metal inputs to ecosystems<br />
have been continuously developed since the mid of the 1990’s in the framework of<br />
UN/ECE Convention on Long-range Transboundary Air Pollution (De Vries,<br />
Bakker, 1998; UBA, 2003). Critical load approach is widely used under CLRTAP<br />
to be based on steady-state mass balance equation of HM in soil layer. If internal<br />
ecosystem fluxes of HM have been excluded from mass balance equation than<br />
critical load can be accounted as a sum of the harmless metal outputs from the<br />
ecosystem minus natural replenishment through weathering. The main outputs of<br />
HM in forest soils are metal leaching with percolation waters and metal removal<br />
because of growth biomass uptake (only wood biomass is considered). This paper<br />
describes some approaches to calculating and mapping critical loads of Pb in<br />
regional scale on the example of forest ecosystems located in the Centre of the<br />
European Russia.<br />
Leaching estimation. In accordance with (De Vries et al., 2002), metal output flux<br />
from the soils with infiltration water regime can be calculated on the base of<br />
following equation:<br />
M le<br />
= 10 * Q le<br />
* [M] ss (1)<br />
where: Mle – metal leaching from considered soil layer (usually, mineral topsoil),<br />
[g/ha.yr]; Qle – flux of drainage water leaching from soil layer, [m/yr]; [M] ss –<br />
metal concentration in soil solution, [mg/m 3 ]. The factor 10 is needed to convert<br />
the unit from mg/m2.yr to g/ha.yr.<br />
Metal concentration in soil solution ([M] ss ) which depends on main soil properties<br />
(pH, h and clay) and metal concentration in solid phase are accounted using special<br />
transfer functions (UBA, 2003). The results of calculating for the main soil types<br />
from the background sites in the central Russia are presented in Table 1.<br />
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