TIMBRE Guidline on Tree Coring

As public version of the TIMBRE Deliverable D4.2, a Guideline for application of Tree Coring as an initial screening tool for typical pollutants in the subsurface is available.

This guideline is an outcome of the work accomplished in TIMBRE working package 4 - Strategies and technologies for integrated site characterisation and remediation are investigated.  One of the tasks coordinated by DTU was to test the feasibility of vegetation sampling as a screening tool for typical pollutants in the subsurface.  

Previous guidelines of tree coring as bio-indicators for subsurface pollution are available (Holm et al. 2011ab, Trapp et al. 2012, Vroblesky 2008). These guidelines report that tree coring is more or less useful for a variety of volatile organic compounds (VOC) such as BTEX (benzene, toluene, ethylbenzene, xylenes), methyl tert.-butyl ether (MTBE), trimethyl benzene and chlorinated solvents (PCE, TCE, DCE, VC). This new guideline goes beyond the previous guidelines, and the main novelty is that it also includes the application for screening of heavy metals, plus some new examples for BTEX. It is based on field applications at sites polluted with BTEX, chlorinated solvents and/or heavy metals.

The guideline describes the method and the application of it including sampling, chemical analysis and data treatment. Finally a short overview of current literature obtained within the TIMBRE project and by others is given.

References:

Algreen, M, Trapp, S. (2014) Guideline for application of Tree Coring as an initial screening tool for typical pollutants in the subsurface. Public shortened and modified version of restricted Deliverable D4.2 version 3 of EC funded TIMBRE project (FP7-ENV-2010.3.1.5-2-265364), 26 p --> Download.

Holm O, Rotard W, Trapp S, Dési R. (2011a.) Guide to Phytoscreening - Using tree core sampling and chemical analyses to investigate contamination in the groundwater and soil --> Download.

Holm O, Rotard W, Trapp S, Dési R. (2011b.) Arbeitshilfe zum Phytoscreening - Probenahme und chemische Untersuchung von Bohrkernen aus Bäumen zur Erkundung von Grundwasserschäden und Bodenbelastungen. Arbeitshilfe für Ingenieure, erstellt im Auftrag des Terra-, Aqua- und Sanierungskom-petenzzentrums TASK 2011 --> Download.

Vroblesky DA. (2008). User´s guide to the collection and analysis of tree cores to assess the distribution of subsurface volatile organic compounds. U.S. Geological Survey Scientific Investigations Report 2008-5088. --> Download.

TIMBRE results on site characterization and remediation

The final deliverable on "Comparative study of site investigation approaches and potential in situ remediation techniques: model-assisted evaluation of advantages and uncertainties" has been published

Based on the developed site models, a comparative assessment of possible in situ remediation techniques pointed out which measures may, or may not, be successful at the studied Timbre sites. Concerning in situ remediation techniques, phytoremediation, specific soil-flushing and DP-based approaches (injection of microbial substrates or chemical oxidants) were considered in the comparative study.

In May 2015, results were published in an open access paper in the Springer journal Environmental Science and Pollution Research. The paper presents the results of the application and tests of different site charaterization techniques conducted in the TIMBRE project.

This paper illustrates the usefulness of pre-screening methods for an effective characterization of polluted sites. The authors applied a sequence of site characterization methods to a former Soviet military airbase with likely fuel and benzene, toluene, ethylbenzene, and xylene (BTEX) contamination in shallow groundwater and subsoil. The methods were (i) phytoscreening with tree cores; (ii) soil gas measurements for CH₄, O₂, and photoionization detector (PID); (iii) direct-push with membrane interface probe (MIP) and laser-induced fluorescence (LIF) sensors; (iv) direct-push sampling; and (v) sampling from soil and from groundwater monitoring wells. Phytoscreening and soil gas measurements are rapid and inexpensive pre-screening methods. Both indicated subsurface pollution and hot spots successfully. The direct-push sensors yielded 3D information about the extension and the volume of the subsurface plume. This study also expanded the applicability of tree coring to BTEX compounds and tested the use of high-resolution direct-push sensors for light hydrocarbons. Comparison of screening results to results from conventional soil and groundwater sampling yielded in most cases high rank correlation and confirmed the findings. The large-scale application of non- or low-invasive pre-screening can be of help in directing and focusing the subsequent, more expensive investigation methods. The rapid pre-screening methods also yielded useful information about potential remediation methods. Overall, the authors see several benefits of a stepwise screening and site characterization scheme, which they propose in conclusion.

You can download the paper here. For the online-first published version, refer to the following reference:

Algreen, M., Kalisz, M., Stalder, M., Martac, E., Krupanek, J., Trapp, S., Bartke, S., (2015): Using pre-screening methods for an effective and reliable site characterization at megasites, Environ. Sci. Pollut. Res., doi: http://dx.doi.org/10.1007/s11356-015-4649-6

Update on test sites’ knowledge status

A key Timbre target – dealt with in Working Package 4 – is an improvement of existing methods and technologies to support brownfield regeneration. Such aims can be accomplished by approaching methodological core topics such as intelligent remediation in terms of technological advancements with regard to phytoremediation and partial source removal technologies. Smart and efficient investigation technologies bring a very solid support for remediation assessments, with key inputs into site regeneration strategies.

A report published in September 2013 presents the knowledge status reached within WP4 in relation to the Timbre model sites in Szprotawa (Poland) and in Hunedoara (Romania). This document represents a brief version of Timbre’s official - but due to data protection restricted - Deliverable 4.1 “Updated site knowledge status (database and site model) as a result of integrated DP and SSP investigation (database and site models implementing updated information from DP/SSP and potentially plant investigations)”, which was due and delivered to the European Commission in March 2013.

In the report, an overview is given for both sites; results were fully included in two GIS-based site models developed at IETU (Szprotawa site) respectively at UTCB (Hunedoara site) and are available as of publication of this report for all partners in the project. As on request, restricted data may be made available to selected interested parties. Please contact timbre-info@ufz.de for any requests and further general information about the activities in WP4 and the Timbre project in general.

You can download the report be following this link: Public briefing on Timbre project’s test sites’ knowledge status (database and site model) as a result of integrated site investigation techniques (based on Deliverable D4.1)

Improving remediation technologies

Interim report as of June 2012

Field campaigns for investigating subsurface pollution have been carried out at the timbre sites Hunedoara, Romania, and Szprotawa, Poland. This work aimed at testing, (further) developing and comparing methodologies, including direct push (DP)-based subsurface investigations and tree core sampling.
DP investigations were done in order to investigate subsurface contamination and properties (in situ measurements and sampling of soil, soil gas and groundwater). Tree core sampling, i.e. the sampling of wood and subsequent chemical analysis, was done in Hunedoara. BTEX, naphthalene and heavy metals were detected in trees, and relation to soil concentrations are currently being analysed. Further analyses (PAH) are currently under way. Aims are to test the feasibility of this rapid, (cost)-effective and low-invasive methodology for obtaining screening-level information on subsurface pollution.
At the Szprotawa site, results on soil and groundwater contamination obtained from percussion-drill probing were correlated with BTEX concentrations measured in soil gas. The latter enables obtaining semi-quantitative data on contaminant distribution quickly and at relatively low costs, and first results of a reconnaissance study from March 2012 were very promising. Next campaigns at both sites are planned for September and October 2012.

Specific soil washing with recycled fluids has been investigated at the pilot scale (in laboratory). For studying the removal of creosotes, soil treatments involved foams with recovered solutions of surfactants. Several surfactants have been evaluated, and a zwitterionic, innocuous surfactant has been selected due to its performances (extraction efficiency, low sorption in soil, repeatability, high flux through the soil, high biodegradability). A simple treatment of contaminated foams (physical de-foaming and ultrafiltration) allows to reuse the decontaminated solutions for making new foams. The in-situ treatment will be tested in September 2012 at the real scale at the site Solec Kujawski, Poland, in collaboration with the EU-project HOMBRE.