Timing, hosts and locations of (grouped) events of NanoImpactNet

The exposures to be conducted will utilize a range of
environmentally relevant species in different exposure media
and will measure a range of endpoints, thereby improving the
current state-of-the-art. Variables such as aggregation and
dissolution of ENPs will be monitored in the test media using
qualitative and quantitative methods. Our experiences will also
allow us to recommend refinements to existing ecotoxicity test
protocols for ENP studies and will provide information that can
be used to investigate approaches for calculating predicted noeffect
concentrations in WP 6.
Obj.6: Establish and model how environmental physico-chemical
properties in wastewater, natural waters and soil govern ENP
parameters such as stability, soil–solution partitioning,
downward transport and transformation (e.g. dissolution) that
each may ultimately affect bioavailability to organisms.
Baseline. The properties of the selected ENPs will be
characterised in detail (in WP 1); however, the consequences of
these properties for behaviour of the ENPs in the natural
environment (e.g. aggregation/dispersion, association with
natural organic matter, binding to suspended sediments and
soils, dissolution rates) have so far not been studied. Although
knowledge of the behaviour of natural metal oxides suggests
that chemical factors (e.g. dissolved organic matter, pH, ionic
strength) should influence the stability of metal oxide ENP, the
bioavailability of ENPs to organisms has only been studied in
simple or environmentally unrealistic systems, and it is unknown
how these factors affect ENP uptake and toxicity. Work has
been published showing that both pH and the presence of
naturally occurring macromolecules can influence the
dissolution and aggregation of ENPs and it is likely that these
affects may change bioavailability (Baalousha, et al. 2008;
Diegoli, et al. 2008).
NanoFATE progression beyond the “state-of-the-art”. In
NanoFATE we will address the role of water and soil
physicochemical properties and particle characteristics by
determining the magnitude of ENP effects for key organisms
exposed to different particle types and under different
environmental conditions. Specifically we will adopt the
following approach.
1. Conduct tests to measure the toxicity of a selected set of
ENPs in a set of soils and waters of known physicochemical
properties (VUA, UAVR, CU).
2. Account for the role of dissolved metal in toxicity, by
linking information on dissolution rates to predictions of
free metal ion concentration using the Windermere Humic
Acid Model (WHAM) (Tipping 1984) or empirical
relationships with either the free ion activity model (Morel
1993), free ion effective dose model (Lofts et al. 2005,
2006) or biotic ligand model, as a prediction of available
exposure and associated effect (DiToro et al. 2001) (NERC,
VUA, UAVR).
3. Quantify additional toxicity (if any) beyond that predicted
to be caused by the free metal ion.
NanoSafetyCluster - Compendium 2012
4. Use multivariate statistical methods such as principal
component analysis and partial least squares regression to
investigate the relationships between ENP derived toxicity
and soil and water chemistry (VUA, NERC, UAVR).
5. Investigate the use of rate transfer constants as a means to
account for dissolution and the subsequent transfer of the
causation of toxicity from ENP to free metal ion forms
(VUA, NERC).
Meeting this objective will require integrative working among
ecotoxicologists and environmental and physical chemists. We
will need to quantify how physical properties of ENPs change
with time in diverse chemical environments and how this affects
ENP exposure. The information derived from these studies will
allow us to modify assessments of risk in receiving waters and
soils made in WP 6.
Obj.7: Establish the mechanisms of uptake, internal trafficking
and toxicity of ENPs.
Baseline. To date, information on the toxicokinetics of ENPs is
very sparse. Very little is known of their uptake, internal
trafficking and distribution and the effects of ENP properties on
these parameters. This is despite the fact that these aspects are
important to understand mechanisms of action and long-term
effects of ENPs.
In relation to mechanisms of toxicity, some observations do
indicate that nanoscale materials used in biomedical and
pharmaceutical research may modulate the expression of
cancer genes (Omidi et al., 2003), and genes involved in cell
signalling (Regnstrom et al., 2006). For ENPs, recent studies
have indicated genotoxicity and cytotoxicity in cultured human
cells and generation of pulmonary fibrosis and lung tumours in
rats (Wang et al., 2007). Such effects have, however, only
recently been studied in aquatic organisms (see review of
Moore, 2006; also Klaper et al. 2009; Shinohara et al. 2009) and
we know of no published genotoxic studies in terrestrial
invertebrates (although NERC have submitted a paper on ENP
immunotoxicity in earthworms) and only a single molecular
toxicity study for terrestrial plants (Lee et al. 2009).
Compendium of Projects in the European NanoSafety Cluster 99
A