Particles
Eawag News 66, August 2009
complete issue [pdf, 7MB]
Editorial: Eawag News - a bridge between research and practice
Martina Bauchrowitz
In Fokus
Studying the ultramicroscopic realm
Martina Bauchrowitz
The Eawag
Particle Lab focuses on the analysis of colloids, which consist of particles
measuring less than 1 µm. A wide variety of techniques are used to study, for
example, colloidal particles in road runoff or the behaviour of synthetic
nanoparticles in the environment. [...]
Nanoparticles in drinking water
Ralf Kägi
Synthetic
nanoparticles are increasingly being used in everyday products, but little is
known about environmental releases of these materials. Our knowledge of how
many natural nanoparticles occur in drinking water is also inadequate. An
initial assessment is presented here. [...]
Buried in lakes - how carbon ist stored in sediments
Sebastian Sobek
Vast
quantities of carbon are stored in lake sediments. By reducing concentrations
of CO2 in the atmosphere, the sequestration of carbon in sediments counteracts
the greenhouse effect. An Eawag research team has now discovered how carbon is
stabilized in lake sediments over long periods. [...]
Arsenic removal using iron colloids
Ralf Kägi
Drinking water
contaminated with arsenic can be treated using filters in which arsenic is
adsorbed onto iron colloids. However, the performance
of these systems may not be optimal, depending on the composition of the
water. Eawag has now investigated the processes involved – and how the design
of future filters could be optimized. [...]
Current research
Organic matter, light and contaminant degradation
Silvio Canonica
Dissolved
organic matter consists of organic compounds, mainly of natural origin.
Although it is only present in trace amounts in surface waters, organic matter
influences the fate of contaminants. Under the action of sunlight, it can
either increase or decrease the rate at which contaminants are degraded. [...]
Modelling of benthic communities in rivers
Nele Schuwirth
The Ecological
River Model (ERIMO) developed by our group makes it possible
to simulate key processes in running waters. Our modelling covers benthic algae
and invertebrates and takes model uncertainties into account. [...]
Promoting Sodis effectively
Andrea Tamas and Silvie Krämer
The basic idea
of solar water disinfection (Sodis) is simple: water is purified by being
exposed to direct sunlight for 6 hours in a
PET bottle. But despite the straightforwardness of the method and the benefits
to health, Sodis has not been adopted as widely or rapidly as people might
think. [...]
Nitrosamines - a water safety risk?
Martin Krauss
Nitrosamines
are probable human carcinogens. As well as being ingested with food, these
substances are produced by chemical reactions in the stomach. In the light of
findings concerning contamination of drinking water in the US and Canada, we
investigated whether nitrosamines could also pose a risk to water resources in
Switzerland. [...]
Nonylphenols: degradation and estrogenicity
Frédéric Gabriel and Hans-Peter Kohler
Nonylphenols,
which are endocrine disruptors, always occur as a mixture of different isomers.
New findings indicate that the isomers are differentially degraded by bacteria,
and the estrogenic risk posed by the mixture may even be increased in the
process. [...]
Various
No food without water
An interview with Eawag scientist Hong Yang
Water
shortages pose a serious threat to humanity and will have wide‑ranging consequences in various sectors, including
agriculture.
Where does Eawag News go from here?
Since it was
first launched in 1973, Eawag News has been addressed to a steadily growing
circle of subscribers – both nationally and internationally. But who exactly
reads Eawag News? And does Eawag News meet its readers’ requirements? Answers
are provided by the survey conducted in April 2008