WORK PACKAGE 3: INTEGRATED HAZARD ASSESSMENT

Results so far: Toxicity of silica particles is dependent on particle size and surface properties. Bengt Fadeel’s research team has conducted toxicity screening of a panel of silica nanoparticles using a human immune derived cell line. The smaller particles were found to be more toxic than their larger counterparts. It is also worth noting that some of the particles did not elicit any cytotoxicity at the doses tested.

In the Mistra Environmental Nanosafety Program, research on the toxicological effects of nanoparticles is made on both aquatic and human cells and organisms. In close collaboration, the same particles are used to investigate effects on cellular, organismic and ecological levels in different laboratories and experimental model systems. Focus is on the relation between physico- chemical properties and the environmental hazards of selected nanoparticles. The particles mentioned above were obtained from Dr. Mikael Persson at AkzoNobel and from the nanomaterial repository at the Joint Research Centre of the European Commission.

Bengt Fadeel and Kunal Bhattacharya, Karolinska institutet, Institute of Environmental Medicine

How hazardous are engineered nanomaterials?

Professor Bengt Fadeel’s research team at the Institute of Environmental Medicine, Karolinska Institutet, assesses the hazard potential of engineered nanomaterials for human health, using human in vitro (cell- based) model systems. Kunal Bhattacharya, Assistant Professor in the team, is testing a panel of different silica particles obtained from program partner AkzoNobel using immune cells. This work is complementary to the work at the University of Gothenburg (where Zareen Abbas team has found that the surface charge of silica particles increased as the particle size decreased), and Lund University on the ecotoxicity of nanomaterials.

“Industry needs to prevent environmental hazards before taking new or modified nanomaterials into production. The Mistra program on Environmental Nanosafety is the biggest academic research project on nanosafety to date in Sweden and we are very excited to be a part of this project. It is important to consider the overall impact of engineered nanomaterials, both in terms of the environmental impact, but also the potential impact on human health,” says Bengt Fadeel.

Björn Stolpe, Akzo Nobel Pulp and Performance Chemicals

A detailed understanding of the hazard potential of nanomaterials makes it possible not only to offer advice on the regulation of these materials in order to protect the environment and human health, but also to produce new nanomaterials that are “safe-by- design”; this means to guide the development of new nanomaterials so that the harmful effects are minimized while retaining the useful properties of the materials (see WP 5).

Tungsten carbide nanoparticles do not have acute negative effect on the tested aquatic wildlife

Tests are made of the toxicity of nanoparticles and other biological effects, such as behavior and reproduction, on aquatic organisms, at Lund University’s departmentt of Biochemistry and Structural biology and the Aquatic Ecology unit. They also study how nanoparticles travel through an ecosystem, up the trophic levels. Mikael Ekvall, post doc researcher, has tested the effect of tungsten carbide nanoparticles on three aquatic organisms: zooplankton (Daphnia magna), fish (Carassius carassius) and a benthic isopod (Asellus aquaticus). These three organisms represent different levels in a food chain and inhabit different locations in a lake ecosystem. Daphnia magna is exposed to nanoparticles either directly or after incubation of nanoparticles with algae that is fed to the Daphnia. Asellus is exposed to sedimenting nanoparticles with or without mixing with algae. Although nanoparticles are taken up by Daphnia, they see no acute (24 hour of exposure) toxicity even in high concentrations of nanoparticles. Prolonged studies of reproduction, and for Asellus also food processing, do not indicate negative effects of the nanoparticles. The fish were exposed to the tungsten-containing nanoparticles after the particles were first taken up by Daphnia that were then fed to the fish every second day. After 4 weeks of treatment, no acute toxicity was observed in the fish. Their results indicate that tungsten carbide nanoparticles do not have acute negative effects on the tested aquatic wildlife.

Zooplankton died after two weeks

When the team prolonged the exposure of tungsten carbide nanoparticles to zooplankton Daphnia magna, for two weeks, the zooplankton died. The concentration of volfram carbide was taken from a road-drain test. The result indicates that even low concentrations can be toxic if the zooplankton are exposed during a longer time. The group will also test the effects on aquatic wildlife for WC-Co.

Lars-Anders Hanson and Mikael Ekvall, Lunds University, dept of Biology.

 

Ecotoxicologists develop models for characterization

Thomas Backhaus, Professor at the Department of Biological & Environmental Sciences at the University of Gothenburg, wants to improve the hazard and, consequently, environmental risk characterization of commonly used nanoparticles. His research team aims to provide a detailed ecotoxicological characterization of silica nanoparticles and to develop structure–activity relationships (QSAR:s) for metallic nanoparticles.

“In order to protect the environment and human health we need an adequate risk management to be implemented. That in turn requires substantial scientific knowledge in order to be sufficiently protective, without jeopardizing the development of new products. Unfortunately, far too often safety research lags substantially behind technological development, driven by economic prospects. With our research, we hope to contribute to closing the gap” says Thomas Backhaus.

Their current work contributes to improving the environmental safety of products containing silica nanoparticles. By systematically testing a suite of relevant silica particles in a broad range of systems and organisms, they hope to provide a holistic hazard profile that identifies sensitive organisms and endpoints. This is a basis for appropriate risk management and, if necessary, risk mitigation measures.

Frida Book, University of Gothenburg Dept of Biolocial and Environmental Sciences

A new generation researchers

Thomas emphasizes that one of the strengths of the program is the training of the next generation of scientists, that will be familiar with the challenges of nanoparticle safety assessment. This will help to further improve the practice of nanosafety assessments. In his own lab, PhD student Frida Book is working jointly with the lab of Joachim Sturve, Associate Professor at the Department of Biological & Environmental Sciences at the University of Gothenburg. Last autumn, Frida began studying a range of silica nanoparticles of varying properties in bacteria, algae as well as rainbow trout and cell culture systems.

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