Exposure to organochlorine chemicals is linked to reduced bone mineral density among polar bears from East Greenland, according to a study published today in the December issue of the peer-reviewed journal Environmental Health Perspectives (EHP). In the study of 139 polar bear skulls, researchers compared 41 samples collected between 1892 and 1932 with 98 samples collected between 1961 and 2002. Bone mineral density in the skulls collected before 1932—considered “pre-pollution” by the researchers—was significantly higher than that in skulls sampled in the “post-pollution” period after 1961, when scientists first began seeing organochlorines and other persistent organic pollutants (POPs) in the fat of polar bears.
The researchers also analyzed a subset of 58 skulls collected between 1999 and 2002 to examine the organochlorine body burden in relation to bone mineral density. In this group, exposure to PCB compounds and to chlordane (a now-banned insecticide) both correlated with low bone mineral density among younger bears. In adult males, concentrations of dieldrin (another banned insecticide) and total DDT residues also correlated with low density.
POPs resist breakdown, store easily in fat, and bioaccumulate through the food chain. Once widely used in agriculture and industry, several types have been classified as probably or possibly carcinogenic to humans, and there are now restrictions or bans related to their application. However, these highly toxic chemicals are very stable over time, and they remain widely present in the environment, where they still pose a serious health threat.
Value from wastewater
16.08.2017 | Hochschule Landshut
Species Richness – a false friend? Scientists want to improve biodiversity assessments
01.08.2017 | Carl von Ossietzky-Universität Oldenburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
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17.08.2017 | Physics and Astronomy