Many young men have a low sperm count and more and more boys are born with malformed sexual organs. A little less than five per cent of all Danish boys are, for example, born with hypospadias, where the opening of the urethra is on the underside of the penis. Substances disturbing the hormonal balance during the foetal development have long been suspected of being one of the causes of such birth defects.
"Several animal tests have shown that endocrine-disrupting chemicals, which have an effect on the male sex hormone testosterone, can result in such malformations in young male rats. In vitro testing and short-term animal testing have also suggested that concurrent exposure to several chemical substances can result in endocrine-disrupting effects even if exposure to each individual substance does not show any effect. We are now able to document that this is actually the case," says Ulla Hass, senior scientist at the National Food Institute, Technical University of Denmark.Significant cocktail effects
The three chemicals were administered in doses which are harmless individually. Concurrent exposure to the three substances did, however, show significant cocktail effects. The male rats did, among other things, develop female characteristics in the form of retained nipples and severely malformed external sexual organs. Sixty per cent of the male rats were, for example, born with hypospadias.Underestimated risk
"Our studies show that concurrent exposure to several endocrine-disrupting substances in small doses can increase the frequency of malformations such as hypospadias even though the doses are harmless individually. It is therefore not sufficient to establish reference values only by looking at one substance at a time," concludes Sofie Christiansen, PhD student at the National Food Institute, Technical University of Denmark.
"In order not to underestimate the risk of chemicals to humans, it is important to include the possible concurrent exposure of two or more chemicals in the risk assessment. To establish an adequate protection level for consumers, potential cocktail effects should be taken into account, and thus the way a chemical may interact with other chemicals," adds Ulla Hass.
Ulla Hass | alfa
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...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy