Sustainable maNagement of sOil and groundWater under the pressure of soil pollution and soil contaMinAtioN Project No. SN-01/20 SUMATECS Sustainable management of trace element contaminated soils – Development of a decision tool system and its evaluation for practical application Final Research Report Start date of project: Project duration: 29.10.2007 12 months (2007-2008) End date of project: 28.10.2008 Project coordinator: Preparation: Dr. Markus Puschenreiter 23.12.2008 Name of coordinator organisation: Revision: Universität für Bodenkultur Wien (BOKU) Final Report, version 2.0 Sustainable maNagement of sOil and groundWater under the pressure of soil pollution and soil contaMinAtioN Submitted by Dr. Markus Puschenreiter on behalf of the SUMATECS consortium Signature: Vienna, December 23, 2008 Authors of this report: Adriaensen Kristin (HAU)* Bert Valerie (INERIS) Böhm Katharina (LfUG) Brignon Jean-Marc (INERIS) Cochet Nelly (UTC) Cundy Andy (UoB)* Denys Sébastien (INERIS) Friesl-Hanl Wolfgang (ARC)* Gombert Dominique (INERIS) Haag Rita (RUB) Hurst Stephanie (LfUG) Jaunatre R. (INRA) Jollivet Pascal (UTC) Kumpiene Jurate (LTU)* Magnie Marie-Claire (INERTEC) Marschner Bernd (RUB) Mench Michel (INRA)* Mikhalovsky Sergey (UoB) Müller Ingo (LfUG)* Onwubuya Kene (UoB) Puschenreiter Markus (BOKU)*,** Raspail F. (INRA) Renella Giancarlo (UniFi) Rouïl Laurence (INERIS) Ruttens Ann (HAU) Schoefs Olivier (UTC) Soularue J.P. (INRA) Stolz Rosel (RUB) Tack Karin (INERIS) Teasdale Phill (UoB) Tlustoš Pavel (CULS) Vangronsveld Jaco (HAU) Vialletelle Frédérique (INERTEC) Waite Steve (UoB) * WP coordinator ** project corrdinator Project No. SN-01/20 SUMATECS Sustainable management of trace element contaminated soils – Development of a decision tool system and its evaluation for practical application Final Research Report This report is the result of work jointly funded by the following SNOWMAN partners: The execution of this project was possible under the umbrella of the European Commission’s 6th Framework Programme project SNOWMAN (contract no ERAC-CT-2003-003219). SN-01/20 SUMATECS Final Research Report 1 Abstract The development of “gentle”, in-situ remediation technologies (i.e. phytoremediation, in situ immobilisation, etc.) has been under intensive research over the last few decades. A great deal of progress has been achieved at the experimental level, but the application of these technologies as practical solutions is still at its early stage. First; methods for determination of the trace element (metals and non-metals) fractions relevant for their ecotoxicology (i.e., the bioavailable fraction) still have their limitations since they may insufficiently reflect the potential risks. Second, a number of gentle in-situ remediation options are available and thus a decision tool system has to be developed allowing to choose the most suitable technique. Third, the application of gentle remediation options may have significant implications for the environment and the socio-economic situation of the local population. TECS (trace element contaminated soils) management moved into a new century where environmental decisions must be ‘socially-robust’ within a context of sustainable development and is a part of the conceptual framework “Risk-based land management”. All efforts need to ensure management and/or remediation is affordable, feasible, effective and sustainable. The aim of this project was to summarise the current state of the art using data from literature (SCI journals, project reports) and from a questionaire that has been sent to all kind of experts involved in remeddiation of trace element contaminated soils (scientists, stakeholders, policy makers, etc.). All collected information was used to identify the current status of research and application in Europe and to (i) derive decision tool systems, remediation scenarios including the potential impacts on the local environment and (ii) define further research needs. A SNOWMAN funded research project 1 SN-01/20 SUMATECS Final Research Report 2 Executive Summary State-of-the-art of research and development of various gentle remediation options Phytoremediation holds great potential and in order to develop this potential a multidisciplinary approach is required. The success of phytoextraction, as an environmental cleanup technology, depends on several factors including the extent of soil contamination, metal availability for uptake into roots (bioavailability), and plant ability to intercept, absorb, and accumulate metals in shoots. In order for phytoextraction to evolve into a suitable technique, either the extraction efficiency requires to be further increased or the produced biomass needs to have an economical value (e.g. for bioenergy production). In addition, when taking into account the achievable mass of metals which can be reasonably extracted per hectare and per year, it becomes evident that the technology is only applicable to decontaminate soils with low to moderate metal concentrations. For soils with a high load or with a deep penetration of metals, phytoextraction is not a realistic option. In those cases phytostablization is recommended instead. The efficiency of phytostabilization can also be further increased by optimizing agronomic practices, such as irrigation, fertilization, planting and harvest time and the timing of amendment application. To conclude, more fundamental research is still needed to better exploit the metabolic diversity of the plants themselves, but also to better understand the complex interactions between contaminants, soil, plant roots and micro-organisms (bacteria and mycorrhiza) in the rhizosphere. Review and evaluation of the existing methods for determination of the bioavailable trace element fractions in soil Bioavailability of trace elements is not a single value that can be measured by a single chemical or even biological method. It is a process that, as any processes in nature, varies in time and space. We can only estimate a fraction of TE that is bioavailable at that moment and organism in question. Therefore total trace element concentrations in soil are, and most likely will be, considered in risk assessment of contaminated sites, even though they do not reflect the real environmental and health risk associated with the site contamination. Environmental and socio-economic aspects of remediation and related technologies Technological intervention in management and monitoring is needed to shorten the restoration time, maintenance costs, and final destination. The reviewed literature shows that evolution of phytoremediated sites is reflected in increased functionality of contaiminated soils or spoils wastes. Soil functions, being sensitive to the pedo-environmental conditions and responsible for biogeochemical nutrient cycles, can be used as synthetic indicators of the progress and also the efficiency of given phytoremediation approaches. However, their use should be coupled to the knowledge of the site history, and related to the development of the soil profile and to the organic matter content and humification. In evaluating the biochemical parameters in relation to SUMATECS and progress of the vegetation the nutrient cycling should be assessed, to better the eventual plant-soil-microbe balance of nutrients, to prevent nutrient shortage. Better study of soil formation, evolution and fertility is important for an optimal SUMATECS, because often after treatment use is proposed on an unsuitable soil. It is concluded that further research should focus on systematic studies on the short- and long-term effects of gentle remediation technologies on soil biological parameters and on the identification of general and site- specific sensitive biological indicators for the restoration of soil functions. Biomass valorization of highly contaminated plant material is an unsolved problem. Nevertheless, a lot of research is ongoing and should give technological answers in the near future. Regarding regulations and plants that are used or that should be used in phytoextraction, it can be assumed that mostly contaminated biomass issued after harvest has to be considered as a hazardous waste. As shown by regulations, the options for hazardous wastes are provided by the landfill directive, the incineration directive and any other possibly recovery solution. As a pre-requisite, it is not allowed to mix hazardous wastes with other hazardous wastes, or with any other wastes, substances or matters. Mixture includes dilution of hazardous wastes. Contaminated biomass can’t be placed in landfill for hazardous waste because one criterium for acceptance A SNOWMAN funded research project 2 SN-01/20 SUMATECS Final Research Report is not met. An incineration plant means any technical equipment used for the incineration by oxidation of hazardous wastes with or without recovery of the combustion heat generated, including pre-treatment as well as pyrolysis or other thermal treatment process. Our results show that composting or leaching may be helpful to pre-treat contaminated biomass before incineration in hazardous waste plant. In addition, our results may suggest that the ash residue enriched in metals would be placed in a hazardous landfill if the ash meets the criteria and in particular the TOC criterium. In such a case, ash can be, for instance, stabilised. Regarding recovery or valorisation, it should be possible to recycle metals from contaminated biomass, residues from incineration and pyrolysis or leachates. Further developments are needed on these aspects