About this project
Contaminated soil is a rapidly growing threat of large proportions to the global environment leading to threats to both ecosystems and humans. Only in Sweden there are some 80 000 sites with contaminated soil, according to the Swedish Environmental Protection Agency (EPA). These contaminated sites originate from different industrial activities and may contain various organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), dioxins, petroleum waste and heavy metals, often in highly complex mixtures. The present situation calls for the need to develop cost-efficient soil cleaning methods to secure and restore the possibilities of safe soil use and function. Clean soil is a highly valuable resource, not only when it comes to safe food production but also in landscaping, soil use in public parks and playgrounds, home gardens and other urban areas that should be protected for the health and being of coming generations. The objective for this project is to develop a novel toxicity-based relative risk assessment technology which then can be used for innovation and improved optimization of soil remediation, relating observed toxicity to the soil background (baseline) toxicity range (BTR). Also included is the use and execution of this present project in collaboration with three remediation companies operating in Sweden, namely; Sita Sverige AB, RGS 90 and Sakab AB. Soil samples from a range of full scale remediations at these companies will be tested in toxicity bioassays to evaluate the bioavailable, total toxicity and related observed toxicity to the BTR. We will exercise the full potential of the bioassays to detect a wide range of toxicants in the contaminated soil and also put their integrated effects into the perspective of the background soil toxicity. In this we aim to express the mechanism-specific toxicity comparing contaminated with clean soil from selected ecological farms of the Swedish University of Agricultural Sciences (SLU). The BTR can then come to serve as a very useful tool for process optimization including risk and quality assessment. The soil samples that are used in the BTR will be collected in sufficient quantities to allow the establishment of a reference clean soil bank that will enable future research projects. We will also sample and test urban soil in a similar manner to get a picture of the general soil toxicity levels in urban environments, generating an urban BTR. The toxicity of soils from the remediation companies will then be compared against the BTR and the urban BTR making it possible to set an acceptable limit of deviation from the corresponding baseline soil toxicity. The outcome of the present study will: 1) help to find new cost-efficient soil remediation methods for soil toxicity reduction, 2) introduce a novel toxicity profiling battery for contaminated soil, and 3) generate Swedish BTR and urban BTR and establish a reference clean soil bank. Previous studies at MTM have found that soil remediation frequently do not reduce the toxicity of contaminated soil in an efficient way (Engwall and Larsson, 2009). The following hypotheses will be tested: The use of our novel battery of bioanalytical toxicity tests for contaminated soil is a suitable approach to more fully characterize and risk assess contaminated soils prior to end usage.