16
January 2009 - Hydrophobic chemicals in
the environment can bioaccumulate to high
concentrations in the lipid-rich tissue
of animals and humans. This is the case,
for example, for the hydrocarbon group,
PAH, a class of compound that includes a
number of environmental pollutants. Researchers
at Denmark’s National Environmental Research
Institute (NERI), Aarhus University and
Lunds University have developed a new method
for determining the chemical activity of
these types of chemical in lipid-rich samples
such as vegetable and fish oils as well
as a mussel sample.
The sample is placed
in a vial containing a long millimetre-thin
silicon tube and after typically 10 minutes
equilibrium is reached between silicon and
sample. Subsequently, a small amount of
methanol is sent through the inside of the
tube. Next, the concentration of the target
analytes in the methanol can be analysed
using an HPLC and chemical activities can
be calculated by multiplying the concentrations
by the analyte-specific activity coefficients
in methanol.
Senior Researcher Philipp
Mayer expects the technique to find a wide
number of applications – from online measurement
in industry, where e.g. food oils can be
checked for toxic substances, to determining
toxic chemical content in animal tissue,
where the researchers have demonstrated
the new technique with regard to PAH in
mussels.
The method has been
published in the recognized international
journal, ’Analytical Chemistry’, which in
this connection has chosen to issue a ‘Research
Profile’ about the work, for which Philipp
Mayer was interviewed .
Senior Researcher Philipp Mayer, NERI,
Research profile: Equilibrium sampling with
mussel. Erika Gebel. Anal. Chem., Article
ASAP
DOI: 10.1021/ac802731a
Silicone Membrane Equilibrator
. Measuring Chemical Activity of Nonpolar
Chemicals with Poly(dimethylsiloxane) Microtubes
Immersed Directly in Tissue and Lipids
Philipp Mayer, Lars Tora¨ng, Nadia Glæsner
and Jan Åke Jo¨nsson. Anal. Chem.,
Article ASAP
DOI: 10.1021/ac802261z.
+ More
More than 100 beavers
in Denmark by the end of 2007
16 January 2009 - The
distribution of beavers was determined by
regular observations and identification
of beaver lodges and core areas by the Danish
Forest and Nature Agency Regional Office,
West Jutland. In total, 28 occupied territories
were recorded; 11 inside the state forest
area and 17 in streams and lakes on private
lands.
The density of territories
is highest in the catchment where the beavers
were reintroduced. The beavers have dispersed
to several streams surrounding the brackish
Nissum Fjord, which is situated 25 km downstream
from the reintroduction area, and they have
established colonies more than 30 km upstream
the fjord. An investigation of 10 territories
showed that the average size of areas affected
by raised water levels was 4.6 ha/territory.
The beaver was reintroduced
to Denmark in 1999, when 18 individuals
from a population in Germany were released
in lakes and streams on Klosterheden State
Forest. Population development, distribution
and the effects of beaver activity on various
nature and environment factors have been
monitored by National Environmental Research
Institute and the Danish Forest and Nature
Agency Regional Office, West Jutland.
