Sulphur Immission in 1990 in the Points of a 16x16 km Bioindication Network of Slovenia

1991

S. 240-247

1 Abb., 6 Tab., 8 Lit. Ang.

Unselbständiges Werk

200044692

The damage extent of forest trees in Slovenia is among the greatest in Europe. Damage causes are diverse. One of them being also air pollution. Sulphur dioxide is probably one of the most frequent and also active toxious substance in the air. The quantity of sulphur emissions is enormous. In 1980 110 mil. tons of SO2 were produced in the world. The greatest emissions of So2 in Slovenia could be established in 1983 when they nearly reached 270 thousand tons. Emission sources are irregularly spread all over Slovenia. Since 1985, air pollution due to sulphur dioxide has become the subject of regular monitoring by means of the bioindication method in the points of a 16 x 16 km bioindication net. The tissue used for the analysis of sulphur content is one- and two-year old Norway spruce needles (Picea abies (L.) Karst.) in regions where the Norway spruce does not occur, the needles of Pinus nigra Arnold or those of Pinus silvestris L. are collected. Analyses results are estimated by means of the classification which is also used in Austria, only limit values have been adapted to the results of analyses obtained in the device SULMHOMAT 12-ADG which is used at the Institute for Forest and Wood Economy. In 1990 an entire analyses was not carried out because needle samples were not collected in the forest enterprises of Brezice, Celje and Postojna and in the bioindication point under the Mangart. The content of sulphur in one-year needles was 0,091-0,178%, the average value being 0,125% and in two-year-needles 0,092-0,200%, with the average of 0,132%. A half of the points (36 points or 50,7%) are to be found in the third or fourth sulphur content class of one- and two-year needles. The limit values for one- and two-year needles according to which bioindication points are classified into the third content class indicate the limit above which damage on forest trees due to detrimental influence of sulphur may occur. The Tolmin, the Gorizia region, Inner Carniola, the Kocevje region and Lower Carniola are the least exposed to harmful influence of sulphur in Slovenia. This has been a well known fact throughout the years since the research has been started in the 16 x1 6 km bioindication network. Central region and the north-eastern part of Slovenia are those which are exposed to sulphur influence to the most. Based on the analysis results for the period from 1985-1990, it can be established that sulphur emission in 1986 and 1987 was a little lower than it was in 1985, since 1988 it has been constantly increasing. The increase of sulphur immission can be established in lowland regions of eastern Slovenia, especially in Prekmurje. A system of regular collecting of samples for sulphur bioindication will have to be secured because only on the basis of the data of all 86 bioindication points of the basic bioindicatin net an objective estimation of immission....