The importance of soil protection in Vorarlberg: the most important soil-related environmental problems and measures

Transcription

1 The importance of soil protection in Vorarlberg: the most important soil-related environmental problems and measures Josef Scherer Environmental Institut of Vorarlberg 1. Introduction In consequence of the forest dieback and water pollution discussion of the sixties and seventies of the last century and due to the problems of sewage sludge disposal during the seventies, in the whole western world awareness grew up for our environment and also for the soil as the last sink of all our emitted contaminants. It was recognized, that soil protection is essential for mountainous countries like Vorarlberg, because with dying forests and the imminent following erosion big parts of the country would become unlivable. On the other side the high rate of agricultural landuse required measures for the sustainment of production of healthy food. 2. The development of Soil Protection in Vorarlberg In Vorarlberg soil protection in the broader sense began around 1985, when the government decided the Sewage Sludge Law with the following bye-law in In addition in 1985 was made a countrywide analysis of satellite photos to obtain information about the local and regional forest conditions. After the implementation of the Sewage Sludge Law and as a result of the above mentioned forest investigation, experts argued for an investigation of soil condition over the whole country. There did not exist any example for such an investigation in Austria at this time. So we were forced to make a pioneer work, which was done After this, soil protection with all its environmental aspects was installed as a branch of the water quality department of the Environmental Institute of Vorarlberg. The assignment of tasks covers Function as Expert of the Country Government & Administration - Comments to drafts on laws, bye-laws, guidelines - Issue of soil related expertises - Participation in regional, national and international workgroups on soil related themes Environmental Soil Monitoring - Soil monitoring at permanent monitoring sites - Theme- und problem-related examinations of soil condition - Soil condition monitoring subject to the Sewage Sludge Law - Investigations of causes and impacts of soil contaminations 31

2 Environmental Consulting and Information Service - Short papers & publications - Consulting service for communities and citizens - Consulting and/or training of students The main focuses of the Environmental Soil Monitoring are - Forest soil investigations - Sewage sludge accounting - Traffic influence on soils - Contamination of garden soils - Radioactive contamination of soils - Humid biotopes as archives for diffuse immissions - Background values - Soil compaction - Surface run-offs and contamination of rivers Other aspects of Soil Protection as soil sealing, soil consumption, waste deposits, contaminated sites, landslides and avalanche risks and so on are handled by several other departments of the Country or Federal State Administration. Multidisciplinary aspects in Vorarlberg are discussed and handled by a workgroup consisting of members of all the involved departments, for example the drafting of the Soil Protection Concept, which was decided by the government in The most important soil related problems and measures in Vorarlberg From the above-mentioned we can derive that one main problem of soil protection in a mountainous country like Vorarlberg concerns the fact, that a big part of the inhabited area is protected by forests against snow avalanches, rock fall and landslide. Therefore it is essential, that forest diseases are recognized early and remedied in consequence. The reasons of forest diseases in Vorarlberg as anywhere on the globe are manifold. But the geographical situation with north to west exposed high mountain slopes causes weather holdups and heightens fallouts of pollutants by the first rainfalls. These pollutants can originate from very large distances as well as from home made sources like emissions from traffic, industry, domestic fuel or farming. So in terms of measures - we have to survey these sources as well as their amounts of pollutants. With the countrywide Soil Condition Survey in 1986 we learned that strong acidification took place during the past decades. As a result of that it was visible that the roots retreated from deeper horizons to the organic surface horizons, causing instability against storms and strong compaction of the mineral soil horizons. To determine the success in consequence of several measures towards the prevention of air pollution we installed two permanent monitoring sites, where we made observations of soil profiles at different sea levels (once), of precipitations by rainfall and of seepage water in three depth levels every two weeks over a period of five years. The results of the observations at the pfänder site are published and can be downloaded from our homepage. They show that we were very successful in eliminating sulphur oxides from the air. At several places we can notice increasing ph-values moving slowly downward in the soil profile. But on the other side we can observe increasing nitrogen oxide inputs by rainfall, which keep supplying 32

3 further acidification. So, for a sustainable recovery of acidified forest soils further measures will be necessary, mainly towards traffic guidance and farming intensity. 80 Permanent Soil Monitoring Site "Pfänder": Nitrate in the Seepage Water (Linear Smoothing over five values) Nitrate [mg/l] cm depth 60 cm depth 90 cm depth Sampling date Fig. 1: Nitrate in Seepage water at the permanent soil monitoring site Pfänder. Due to the geographical situation, as connection from N to S as well as from W to E and as touristic destination especially during the winter, Vorarlberg has to bear an enormous traffic density. As mentioned above, this leads among other things to increased Nitrogen inputs into the forest ecosystems, which locally exceed the so called critical loads by far. But beyond that it also resulted in accumulations of lead in soils, even 1000 m above the main traffic routes. Near the main traffic routes also distinctly accumulated amounts of so called POP s (persistent organic pollutants) are detectable. So we have to classify the problem influence of traffic on soils as very important. One example for our work in this domain is a survey of the soil contaminations along high density traffic routes, where we analyzed heavy metal contents, PAH s and the outwash of the road salt applied during the winter. As we see, there is some correlation between lead content in the soil beside the routes and the traffic density during the last years. The lead content for example is heightened even at roads which were built new some ten years ago. Road salt application in Vorarlberg is a very sensitive theme. Therefore we observed at one site the seepage water at the side-strip in a depth of 60 cm for one year. At the beginning of the measurements we noticed high sodium outwash which resulted from the past spring, while the chloride was at the background level already. In the next spring we saw that the chloride outwash began almost immediately after the application of road salt. We did not find distinct accumulations of road salt compounds except in places where the snowmelt was just ending. 33

4 Sodium [mg/l] 180,0 160,0 140,0 120,0 100,0 80,0 60,0 40,0 20,0 0,0 Sodium in Seepage water sampling date Chloride [mg/l] 700,0 600,0 500,0 400,0 300,0 200,0 100,0 0,0 Chloride in Seepage water sampling date Fig. 2: Sodium and Chloride in Seepage Water at the permanent soil monitoring site Pfänder. Now a soil protection problem resulting from the agricultural landuse. The agricultural landuse in Vorarlberg happens predominantly in terms of farming and grassland use. About ha grassland stands opposite to ca ha of corn fields. The intensity of livestock farming increased since the fifties of the last century as well as the intensity of grassland production. Additional to the farming manure, also large amounts of sewage sludge were applied, especially to cornfields but also to grassland in times before the decree of the Sewage Sludge Law in 1985 and the accordant bye-law in Since then, the industrial dischargers of waste water were forced to invest into in-plant technologies of waste water treatment. So the communal and regional sewage treatment plants were enabled to produce sludges with minor contents of heavy metals and organic pollutants. Since the amendment of the Sewage Sludge Bye-law 1999 in Vorarlberg only the application of certified dried sewage sludge granulates or sewage sludge composts (both called sewage sludge fertilizer) is allowed. The application is only allowed to agricultural land, whose suitability is proven by a soil certificate. These certificates, the certified parcels, each delivery of sewage sludge fertilizer to one of the parcels and the certificates of sewage sludge and sewage sludge fertilizer charges are stored in an electronically accountancy system, which is maintained by our branch. Since the installation of this system in 1999 the way of about tons of sewage sludge dry substance (~ 25 % of the total amount) into the agricultural domain is transparent and well documented. Other works in the agricultural domain are investigations of nutrient losses from farming land towards the groundwater as well as towards draining ditches and rivers. Beyond these environmentally more hazardous problems there is a need for filling some gaps in our knowledge. After the countrywide Soil Condition Survey we knew much more about heavy metal contents of our soils. But how can we explain high metal contents in areas without a probability of human influence? There must be geological reasons. But outside of ancient mining districts we didn t know much about heavy metal and other trace element contents. So we started three years ago with a random sampling survey of geological outcrops all over the country. The analyses were made by the Austrian Research Center Seibersdorf on 46 Parameters, according to the Austrian Atlas of Geochemistry. Until now we sampled 230 outcrops which can show us where we can assume extended values for geological reasons. On the other side we get a higher probability for classifying extended values as human influenced. 34

5 Fig. 3: Distribution of sampling points and Contents of Nickel in geological Outcrops. When I spoke about soil acidification and compaction, then in consequence erosion is another main problem of soil protection. But here we are not able to offer feasible solutions without support by structural engineering measures which are taken by the Federal Ministry for Agriculture, Forestry, Environment and Water Economy (Wildbach- und Lawinenverbauung). The erosion in most cases is faster than the soil recovery by biological methods, especially in steep mountainous areas. 35

6 4. Conclusion I could only give a short overview of problems and measures of soil protection in Vorarlberg. During the past 20 years, there has been done very much for all departments of environmental protection. In the soil protection branch a broad knowledge base has accumulated about chemical and biological processes in soils. After a short phase of stagnation or better: after a short time of acquisition of the gained knowledge a new spark was ignited by the EU with the European Union Soil Thematic Strategy. So we hope that the spark will not go out, but will grow to a big flame! References Scherer, J.: Der Waldboden im Pfändergebiet. Zustand und Stoffdynamik. Schriftenreihe Lebensraum Vorarlberg, Band 55. Amt der Vorarlberger Landesregierung, Bregenz, ionen/boden/pfaenderbericht.htm Scherer, J.: Klärschlammkompost - Kontrollbericht Auswertung der zentralen Klärschlammbuchhaltung für das Jahr Scherer, J.: Bodenschutz Einfluss der Salzstreuung auf den Bodenzustand. ionen/boden/streusalz.htm Vorarlberger Landesgesetzblatt, Jahrgang 1997, 25. Stück, 75. Verordnung: Klärschlammverordnung. 36