Daily Archives: September 25, 2013

Natural oscillations correlate with solar wind speed

Limin Zhoua, Brian Tinsley, Jing Huanga. Effects on winter circulation of short and long term solar wind changes. Advances in Space Research, 2013.

Indices of the North Atlantic Oscillation and the Arctic Oscillation show correlations on the day-to-day timescale with the solar wind speed (SWS). Minima in the indices were found on days of SWS minima during years of high stratospheric aerosol loading. The spatial distribution of surface pressure changes during 1963-2011 with day-to-day changes in SWS shows a pattern resembling the NAO. Such a pattern was noted for year-to-year variations by Boberg and Lundstedt (2002), who compared NAO variations with the geo-effective solar wind electric field (the monthly average SWS multiplied by the average southward component, i.e., negative Bz component, of the interplanetary magnetic field). The spatial distribution of the correlations of geopotential height changes in the troposphere and stratosphere with the SWS; the geoeffective electric field (SWS∗Bz); and the solar 10.7 cm flux suggests that solar wind inputs connected to the troposphere via the global electric circuit, together with solar ultraviolet irradiance acting on the stratosphere, affect regional atmospheric dynamics.

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Toxic effects of Microcystins in potable surface water

Roegner AF, Brena B, González-Sapienza G, Puschner B. Microcystins in potable surface waters: toxic effects and removal strategies. J Appl Toxicol. 2013 Sep 5. doi: 10.1002/jat.2920.

In freshwater, harmful cyanobacterial blooms threaten to increase with global climate change and eutrophication of surface waters. In addition to the burden and necessity of removal of algal material during water treatment processes, bloom-forming cyanobacteria can produce a class of remarkably stable toxins, microcystins, difficult to remove from drinking water sources. A number of animal intoxications over the past 20 years have served as sentinels for widespread risk presented by microcystins. Cyanobacterial blooms have the potential to threaten severely both public health and the regional economy of affected communities, particularly those with limited infrastructure or resources. Our main objectives were to assess whether existing water treatment infrastructure provides sufficient protection against microcystin exposure, identify available options feasible to implement in resource-limited communities in bloom scenarios and to identify strategies for improved solutions. Finally, interventions at the watershed level aimed at bloom prevention and risk reduction for entry into potable water sources were outlined. We evaluated primary studies, reviews and reports for treatment options for microcystins in surface waters, potable water sources and treatment plants. Because of the difficulty of removal of microcystins, prevention is ideal; once in the public water supply, the coarse removal of cyanobacterial cells combined with secondary carbon filtration of dissolved toxins currently provides the greatest potential for protection of public health. Options for point of use filtration must be optimized to provide affordable and adequate protection for affected communities.

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Toxicological Profile for Radon

Toxicological Profile for Radon. Agency for Toxic Substances and Disease Registry (US);Atlanta (GA), 2012 May.

This public health statement tells you about radon and the effects of exposure to it. The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. The presence of radon at any site could be a consequence of its natural occurrence in the environment; its production from substances in anthropogenic hazardous waste; or both. These sites may be sources of exposure and exposure to this substance may be harmful. When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are exposed to a substance when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact. External exposure to radiation may occur from natural or man-made sources. Radon is a naturally-occurring radioactive gas that changes into other radioactive substances, called progeny. Since radon and its progeny are present together in rock, soil, water, air, and construction materials, you will be exposed to the low-level radiation they give off just by being near them. Naturally occurring sources of radiation include radon and other radioactive elements in air, water, soil, or building materials, as well as cosmic radiation from space. Man-made radioactive materials are found in consumer products, industrial equipment, nuclear medicine patients, and to a smaller extent from atomic bomb fallout, hospital waste, and nuclear reactors. The results of the 1992 EPA National Residential Radon Survey estimated that 1 in 15 homes had an elevated radon level (i.e., a level at or above the EPA action level of 4 picocuries per liter of air). At the time, an estimated 5.8 million homes had an elevated radon level. The source of radon in homes is from naturally occurring (geologic) sources. When you are exposed to radon many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.

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