A new report by the National Academies National Research Council on the health effects of perchlorate, a chemical that in high doses can decrease thyroid function in humans and that is present in many public drinking-water supplies, says daily ingestion of up to 0.0007 milligrams per kilogram of body weight can occur without adversely affecting the health of even the most sensitive populations. That amount is more than 20 times the "reference dose" proposed by the U.S. Environmental Protection Agency in a recent draft risk assessment.
Environmental releases of perchlorate -- a component of rocket fuel and fireworks -- have been discovered in 35 states, and more than 11 million people have perchlorate in their drinking water at concentrations of 4 parts per billion or higher. As it considers a first-ever national standard for acceptable levels of perchlorate in drinking water, EPA has issued a series of draft risk assessments, each containing a reference dose upon which a standard could be based. Controversies over the scientific conclusions reached in the risk assessments, however, led the federal government to request that the National Research Council review the issue.
The most recent EPA risk assessment, published in 2002, proposes a daily reference dose of 0.00003 milligrams per kilogram (mg/kg) of body weight, which the agency said would correspond to a drinking-water concentration of 1 part per billion based on certain assumptions about body weight and daily water consumption. The committee that wrote the Research Council report did not include a corresponding drinking-water concentration with its reference dose because the assumptions that are used to derive drinking-water standards involve public-policy choices that were beyond the committees charge.
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26.06.2017 | Charité - Universitätsmedizin Berlin
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An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
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