|NANOkA - NANO Particles: standardization of methods for environmental risk Assessment|
Programme - PTDC/BIA-BEC/103716/2008
Execution dates - 2010-05-01 - 2013-10-31 (42 Months)
Funding Entity - Fundação para a Ciência e Tecnologia
Funding for CESAM - 185072 €
Total Funding - 185072 €
Proponent Institution - Universidade de Aveiro
Additional Research Unit: Centro de Investigação em Materiais Cerâmicos e Compósitos (CICECO/UA)
Nowadays, nanomaterials (NM) are starting to be used in several applications, e.g. in skin care products (titanium dioxide, iron oxide and other metal oxides), in structural applications such as coatings (titanium dioxide), catalysts and ceramics (silicon nitride and silicon carbide); in electronics (single wall nanotubes and metal oxides), in biotechnology on targeted drug delivery and biosensors or even in environmental remediation. There are many differences between ordinary chemicals and NPs. Their small size and larger surface area confer specific properties to NM. Increasing of surface reactivity predicts that nanoparticles (NPs) will exhibit greater biological activity per given mass comparatively to the respective bulk materials. A dramatically increase in the use of NPs in the next few years is expected. As with many manufactured products and chemicals, a noteworthy proportion of NMs are likely to end up in the environment, reaching all different compartments. The main goal of this project is to test the hypothesis that the ecological hazard/risk assessment paradigm currently used for risk assessment of chemicals is not valid when applied to NPs. Among the few published ecotoxicological studies with NPs nearly all have focused on the aquatic environment. When in soil, the behaviour of NPs can be particularly complex. It is also agreed universally that NP-specific properties such as chemical composition, particle number and particle concentration, surface area concentration, size distribution, specific surface area, surface charge, and the nature of the nanoparticle shell are important factors that can affect effective exposure of biota. However, no guidance currently exists to describe toxicity according to these nano-specific metrics. There is an urgent need to study how present test-guidelines can be adapted for NPs so that methods and results are more standardized, reliable and relevant. As the current guidelines are made for traditional chemicals, the OECD established a Working Party on Manufactured Nanomaterials (WPMN) to promote international co-operation in studying whether the current OECD test also apply to manufactured NPs. Hence, this project will fit into this strategy, especially since there is a particular need for data in the terrestrial ecosystem. A crucial issue for NP toxicity is to determine if effects can be linked to exposure, and here this is achieved by carrying/investigating the following: 1) a production of highly characterized NPs with a narrow size range, 2) a detailed qualitative and quantitative estimation of exposure, 3) a detailed and well characterized determination of the exposure regime and 4) the toxicological effects. Standardized exposure regimes are currently not internationally available for NPs. Toxicity of NPs does not start de novo: information already available from toxicity testing of traditional chemicals is very valuable for the development of NP testing. Hence, in this project toxicity studies will take their starting point in the already developed test systems internationally developed, those that are in line with the OECD. This includes both the need for exposure characterization and the choice of test species and gross test conditions. The progress beyond the state-of-art in this project is both the development of novel (and seldom seen before) toxicity data for the terrestrial environment, and the strong focus on causality enforced through a thorough characterization of NPs and their exposure regime. A battery of relevant test organisms will be used to assess effects, including different trophic levels and exposure routes. The test organisms will include producers (plants), destruents/consumers (collembolan) and decomposers (earthworms, enchytraeids). Summarizing, the main objectives of this project are to fill critical knowledge gaps in the state-of-art with regards to the environmental toxicity of NPs and to determine if the classical approaches used in environmental toxicology are applicable to NPs. This will be realized through studies aiming to make a causal determination between NP exposure and toxicity, thus contributing to take the most profit of the use of NPs based products without compromising the environmental quality.
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