Sponsor:
German Environmental Agency, Dessau (FKZ 200 95 308/04) and FKZ 202 95 382-7)
Realisation:
Hydrotox GmbH, Stefan Gartiser (project management), Dr. Rudolf Reuther (both projects)
Öko-Institut e.V., Carl-Otto Gensch (FKZ 200 95 308/04)
Project duration:
2002 - 2004
Summary (FKZ 200 95 308/04)
Main objective of the study was to assess the awarding of de-icing agents based on potassium formiate and used within municipal winter maintenance operation with an eco-label, considering the standard DIN EN ISO 14024 methods. For this, an ecological comparison was performed for the product groups of gritting and de-icing agents, also by including a screening life-cycle analysis (LCA). According to our present knowledge, the use of formiate for winter road and way maintenance can not be recommended, although it has very low aquatic ecotoxicity comparable with normal salt (sodium chloride) and calcium/magnesium chloride. Studies on the terrestrial ecotoxicity of formiates are still lacking. Although these organic salts are rather easily biologically degradable even at the low winter temperatures, we do not know how this may reduce their ecotoxicity. However, compared with thawing salts or even with gritting agents, the production of formiates needs more primary energy and one has to calculate with in total about 10 fold higher application costs. Nevertheless, the further use of formiates can still be recommended as substitute for aircraft de-icing fluids (glycols) and for the use of urea on airport surfaces (see RAL-UZ 99). The study elaborated general criteria and requirements for the performance of de-icing agents as well as practical recommendations for a more ecologically compatible winter road maintenance. To further optimise conclusions and approaches, the results of the screening life-cycle analysis should be verified by performing a LCA according to DIN EN ISO 14040, in particular by including a more rigid data analysis. This also needs to close our existing gap of knowledge concerning the terrestrial ecotoxicity of formiates.
Summary (FKZ 202 95 382-7)
In 2002, the German "Jury for Eco-labelling" decided to further develop the basic requirements for the eco-label "RAL-UZ 13" (for salt-free, gritting agents), that exists since 1981. The study presented here was providing the necessary data basis for drafting the revised demands for the quality label that was agreed upon within the framework of a hearing performed on the 21st of September 2004. The fields of application of the granting requirement still include salt-free gritting agents for sidewalks and similar areas. However, due to the recently expressed critical evaluation of the usability and ecological performance of gritting agents, their use in winter road maintenance is particularly excluded. The revision of the requirements considers recent legal developments, like those associated with the German Federal Soil Act, as well as technical guidelines. As one consequence, gritting agents will be evaluated in the future with the help of instructions given by the German "LAGA-Merkblatt 20" ("Criteria for the Material Recycling of Mineral Residual and Waste Substances"). Decisive for the final evaluation are the so-called "Z0" criteria, which allow the unrestricted incorporation of solid materials in soil-related applications. These criteria define limits, for example for heavy metals, both in particulates (after "aqua regia" digestion), and in water extracts of gritting agents. The requirements on the usability of gritting agents with regard to grain size and shape, portion of fines, shock-resistance and edge properties have been defined more accurately compared to the former version of the granting basis, and are adapted to the "German Technical Guidance for Gritting Agents" ("TL Streu"). Furtheron, more aspects from new research activities are described in the presented study, e. g. eco-balance related considerations concerning production, transport, spreading and re-collection of gritting agents. In addition, the impact of dust by gritting agents is also discussed.