Projects / Programmes
Gardens with remediated soils: hazard mitigation and safe food production
| Code |
Science |
Field |
Subfield |
| 4.03.02 |
Biotechnical sciences |
Plant production |
Soil and micro-climate |
| Code |
Science |
Field |
| B410 |
Biomedical sciences |
Soil science, agricultural hydrology |
| Code |
Science |
Field |
| 4.01 |
Agricultural and Veterinary Sciences |
Agriculture, Forestry and Fisheries |
Soil remediation, safe food, urban farming, soil ecosystem services, soil functioning, safe soils, hazard mitigation
Researchers (10)
Organisations (2)
Abstract
Although usually out of our sight, everything in our lives is underpinned by soil – our homes, the food we eat, the water we drink. Across all socioeconomic groups and around the world, initiatives for sustainable use of soil, such as urban farming, are on the rise. These approaches to land use often undermine the fact that soils are the most complex natural system, and that their present vulnerability is unprecedented. Land contamination exists in most industrialized countries and is a growing problem in emerging economies. Particularly alarming is the presence of toxic metals, which are persistent in the soil and difficult to remove. As human population and pressure on limited soil resources are continuously growing, more and more metal contaminated land is expected to be put under agricultural production in a delicate balance of needs, social & economic benefits and health risks.
We are in contact with soils in our everyday life and this proximity increases the probability that soil pollutants may be carried into the human body. Soil remediation & reuse is a solution, and most EU Member States have made the clean-up and restoration of the land a priority. However, historical excavation to landfill wastes soil, while soil-sustainable remedial options are currently not applied beyond the scale of pilot, experimental studies. As a consequence, inhabitants can typically not avoid living in contaminated areas. Furthermore, studies of attitudes to soil contamination show that persons in contact with contaminated soil, such as urban gardeners, often ignore the risk they are exposing themselves too, preferring to focus on the benefits of green, sustainable and local food production. While the increasing demand for food is threatening to reduce health, soil and food quality standards, the problem of use of contaminated soils remains on the margins of scientific debates.
The overall aim of this project is to research the environmental, agronomic, social & economic potential of a unique, cost-effective soil remediation technology which we developed over the past decade and tested on a pilot scale. The internationally patented technological innovation not only removes Pb and other toxic metals from soil by efficient chemical mean (complexation with strong chelating agent EDTA) but also preserves soil as a natural resource. Available pilot data supports the hypothesis that remediated / revitalised soil provides ecosystem services. The construction of necessary remediation plant in Prevalje (Meza Valley, Slovenia) is near completion and for the first time featuring soil-sustainable technology. Sustainable soil remediation technology is therefore at hand. However, soil processes fundamental for success of the sustainable soil remediation/food production concept are scale and time dependent and in this dimension untested. The concept has yet been tested as an environmental & social innovation. For farming on reclaimed land experimental gardens will be constructed with calcareous, carbonate soil (Meza Valley, Slovenia) and acidic soil (Arnoldstein, Austria). Soils differ in pH, a property with the dominant effect on soil ecology and processes. Both sites were exposed to Pb mining/smelting and are co-contaminated with Zn and Cd. Because of the wide range of anticipated “services” of reclaimed soil, effective stakeholder involvement in Charette process is planned as a critical key to the acceptance of soil remediation/food production concept.
The proposed project will pursue two interrelated objectives:
O1 To demonstrate that soil remediation technology is a green and sustainable soil remediation solution (safe food production and ecosystem services and function of soil)
O2 To consolidate the proposed novel soil remediation / food production as a new concept in sustainable eco-design.
The proposed objectives goes beyond the state of the art, providing a pioneering large-scale study of soil, remediated using an innovative technological s
Significance for science
The toxic metals contamination of soil is one of the most pressing concerns in the debate about food security and food safety in Europe and globally. Global governance of soil resources as well as available funds for reclamation and restoration of degraded land to produce crops for localised (urban) food production (and reduction of food millage) seem to be the necessary actions for sustainable development. Driven by the current lack of effective remediation technologies the presumption that benefits associated with urban agriculture outweigh risks posed by elevated soil Pb is gaining grounds.
In particular science will benefit from project by responding to the following hypotheses:
H1.1.1 Full-scale remediation will mitigate hazard more efficiently compared to lower scales due to more stringent physical conditions. H1.2.1 Short-time maintenance of remediated soil at neutral soil water balance prevents secondary emissions of EDTA and toxic metals with leachates. H1.2.2 Bioaccumulation of Pb and other toxic metals in crops and food produced on remediated soil is largely prevented. H1.2.3 Immobilisation further reduces bioaccumulation of weakly bound and exchangeable toxic elements (i.e. Cd). H1.2.4 If there are any toxic metals remaining in the washed substrate, they do not enter the food chain to be found in edaphic animals. H1.2.5 Revitalisation/fertilisation will improve plant performance in remediated soils: improved plant nutrition, growth, enhanced metabolism, CO2 assimilation and reduced stress. H1.3.1 Soil ageing will direct towards less labile and bioaccessible species of toxic metals. H1.3.2 Revitalisation will initiate aggregation and improve structural stability of remediated soils. H1.3.3 Remediation interrupts soil functions/services (e.g. nutrient cycling) due to the loss of biodiversity and complex soil communities (i.e. food-webs). H1.3.4 In Ncycling the impact is higher for nitrification (NH4+ oxidizers are closely related) and lower for denitrification (denitrifiers are phylogenetically more diverse). H1.3.5 Revitalisation will boost microbial biodiversity and enhance turn-over rate of complex substrates, cycling of nutrients, and resilience toward xenobiotics. H1.3.6 Remediation (mechanical damage) reduces soil biodiversity in the following order: bacteria, archea ( fungi ( AM fungi (filamentous nature), and annihilates the edaphic fauna of the treated substrates. H1.3.7 The remediation annihilates the resident fauna, but fully restores the habitat function of contaminates soils for edaphic animals. H2.4.1 Technology Life cycle assessment (LCA) will demonstrate that the proposed technological solution is environmentally sustainable. H2.4.2 Concept life cycle cost-benefit analysis will demonstrate the economic and social viability and sustainability of the concept. H2.4.3. Focus groups in Charette process will encourage stakeholder’s engagement and facilitate concept consolidation.
Significance for the country
Globally:
Availability of efficient soil remediation technologies and reclamation of contaminated land is a powerful tool to revitalize urban degraded areas. Regeneration of physical environment reinforces the social cohesion and can be used for integration of minorities and (increasingly) older urban population. Remediated and revitalized soil can be used for safe plant and healthy food production and thus ease increasing demands for food as world population increase and availability of farmland decrease due to urbanisation and numerous natural and anthropogenic factors. Very few innovative environmental technologies receive recognition at the European market, while in practice, conventional non-sustainable soil practices still prevail. The main barriers to the uptake of alternative technologies are lack of confidence in their effectiveness and a lack of general understanding. The results of the project will rises the confidence in novel remediation technology through demonstrational-scale soil remediation, demonstrational effect of experimental gardens in two countries and active engagement of stakeholders.
Locally for Meza Valley: The Pb-contaminated Meza Valley is home to more than 6000 people in three main residential communities: the towns of Mezica, Crna and Zerjav. In 2007, an on-going action program for reducing the health hazard for people in the Meza Valley was introduced. Actions include education of the local population in risk awareness, improvement of hygiene standards in schools and kindergartens, asphalting unpaved surfaces, constant wetting and cleaning of asphalt surfaces and cleaning of residential facades and roofs. Despite these measures, the results of annual surveys of blood Pb concentration indicated that the number of children with levels higher than 10 µg dL-1 did not change over the 8-years (2007-2015). The conservative use of the Integrated Exposure Uptake Bio-kinetic (IEUBK) model predicted that, after EDTA-soil remediation, the number of locations at which the expected blood Pb level in children was higher than the stipulated 10 µg dL-1 would decrease by 90 and 91% in the towns of Mezica and Crna. Most of inhibitats in Meza Valley tend their home vegetable-gardens: the use of EDTA-remediated soil will enable safe vegetable production.
For Arnoldstein: After several hundred years of emissions which were dispersed over area used for housing, playgrounds, horticulture, forestry, and agriculture the Pb/Zn smelter at Arnoldstein closed in 1992. AIT GmbH (Austrian project partner) has performed several long-term field studies of soil toxic metal immobilisation with various amendments. Results will be compared with results of EDTA-soil washing and of combined washing/immobilisation and will serve as scientific base in further soil-rehabilitation strategy.
Most important scientific results
Final report
Most important socioeconomically and culturally relevant results
Final report
