SRP4. Environmental Toxicology and Chemistry
Research of environmentally hazardous materials – toxic substances that are released by human activity and are harmful to ecosystems as well as to people – is a field that involves biology, physics, chemistry, material science and healthcare. An interdisciplinary institution such as NICPB is therefore highly suitable for the successful development of this field of research and environmental studies continue to be one of the central research strategies of NICPB.
The research in environmental toxicology in NICPB, especially the studies of environmental hazards of metal oxide nanoparticles initiated in 2004 are groundbreaking in the world as reflected in the number of citations as well as in the successful participation in the FP6 and FP7 projects of the European Union.
The strategic goal of the environmental toxicology program is to elucidate the hazard of (industrial) chemicals that are already in the environment or that have the potential to end up there. This goal will be approached by answering the following questions: is it toxic, to whom and how toxic, why toxic and how to assess the toxicity comprehensively and cost-effectively. According to the chemicals regulation in the European Union (REACH) all chemical substances produced in excess of 1 tonne per year (estimated number exceeds 100 000) have to be characterized in terms of toxicity. It is a considerable burden for the European chemical industry (including Estonian chemical industry), since the responsibility of assessments lies on the manufacturer.
A new class of chemicals – synthetic nanoparticles (particles with at least one dimension less than 100 nm) – are already produced in large scale in a variety of compositions, shapes and sizes. Compared to conventional materials, the nanosize particles have novel properties, exploitation of which may lead to breakthroughs is many technologies starting from energy production and ending with medicine. However, the novel properties may also lead to adverse effects for man and the environment.
One direction of the strategic program of environmental toxicology is development of test systems that enable efficient assessment of biological effects of chemicals and nanomaterials. Attention is focused mostly on in vitro tests that allow the assessment of adverse effects and toxicity mechanisms of chemicals and nanoparticles using fast, high-throughput systems. As a rule, the toxicity of chemicals is related to adverse effects on cell membranes and processes of basal metabolism, which can be predicted reliably using in vitro assays (including tests with e.g., bacteria, protozoa and invertebrates). Quantitative Structure-Activity Relationships (QSARs) are widely used for the prediction of chemical toxicity, but only beginning to emerge for nanoparticles as the latter are considerably more difficult to model compared to conventional chemicals.
A prerequisite of toxicity is the contact between the toxic substance and the organism. Another important factor of toxicity is bioavailability: ability of a chemical substance to cross the biological membrane and enter the cell/organism. The mobility of pollutants in the environment (sorption, desorption, solubility, complexation etc.) is being studied in the NICPB. In addition to previously developed environmental chemistry approach the NICPB now possesses the expertise in environmental toxicology that has been used and will continue to be used for the environmental hazard assessment of pollution originating from the oil-shale industry and energy production. The earlier research initiated by NICPB scientists led to the reclassification of one of the most important pollution flows of the oil-shale industry – fresh semi coke – as hazardous waste in 2003, resulting in the change of its deposition according to the rules of the European Union. The current strategic program also aims to develop a method for the separation of hazardous substances from the oil-shale solid waste and explore the possibilities of its large scale reuse. An independent field of work is the study of environmental aspects of the dictyonema shale (rich in e.g., uranium, molybdenum and vanadium) as well as other oil shales.