BLOG
April 17, 2011 at 11:44 am By Roz Potter
Link, Excerpt:
Geiger counters are probably ineffective for consumers in detecting hazardous levels of radiation in food and water at home, scientists, professors and device makers said.
Large samples should be tested in laboratory-like settings to obtain results, said Joseph Rotunda, who heads the radiation measurement division at toolmaker Thermo Fisher Scientific Inc. Determining whether food, water or milk is safe also requires expert knowledge and more sophisticated equipment than the typical devices sold online, said Atsushi Katayama, a member of the Japan Society for Analytical Chemistry.
The ministry recommends using tools known as scintillation counters to detect iodine-131 in milk and vegetables, while devices called “inductively coupled plasma mass spectrometers” should be used to trace uranium.
Buyers should chose an instrument that comes with clear instructions for interpreting results and is sensitive enough to measure background radiation, or about 0.01 microsieverts, Allison and Katayama said. Geiger counters with a digital display and ability to save a log of the results are easier to use and preferable to devices featuring analog screens with moving needles, they said.
Posted in Food Safety, Radiation health risks, Uncategorized, Water Safety | 2 Comments »
April 17, 2011 at 12:37 am By Roz Potter
This document from the EPA indicates that reverse osmosis will remove some radioactive particles from drinking water. Although radioactivity levels in drinking water have been low, the situation at Fukushima is very unstable and could substantially worsen, releasing much larger amounts of radioactive particles in the future. When that happens, it may be too late to install an effective water purification device or system. Link
Excerpt:
Reverse osmosis is a pressure-driven membrane separation process. Water is forced through a membrane with small pores by pressures ranging from 100 to 150 psi. Any molecules larger than the pore openings are excluded from the product stream along with a significant portion of the water. Treated water is collected on the other side.
Benefits
Reverse osmosis has been identified by EPA as a ¿best available technology ¿(BAT) and Small System Compliance Technology (SSCT) for uranium, radium, gross alpha, and beta particles and photon emitters. It can remove up to 99 percent of these radionuclides, as well as many other contaminants (e.g., arsenic, nitrate, and microbial contaminants). Reverse osmosis units can be automated and compact making them appropriate for small systems.
Posted in Radiation health risks, Water Safety | No Comments »
April 16, 2011 at 11:36 am By Roz Potter
From the Department of Nuclear Engineering, UC Berkeley. See link at the bottom of the post.
Notes from your editor: The numbers in parentheses after the radiation activity level indicate the number of kilograms “that one would need to consume to equal the radiation exposure on one round trip flight from San Francisco to Washington, D.C. (0.05 mSV).”
For example, one would have to consume 2, 570 kg of spinach contaminated with Cesium-134, purchased on 4/7/11, to absorb the equivalent radiation from making one SF to DC flight. One kg equals 2.2 pounds. So, for that batch of spinach, one would have to eat 5654 pounds to equal the radiation exposure from one flight.
But is it reasonable to compare the dose from a round-trip airline flight to the amount in particular contaminated foods? Here are some reasons why this comparison may not be valid:
- For an airline flight, the radiation source diminishes rapidly with altitude so that the dose effectively vanishes at low altitudes
- For food, soil (and also milk, water and other sources) that have been contaminated, radioactivity persists. Once radioactive materials are taken into our bodies, they stay there for varying periods of time, until they decay or are excreted. Meanwhile, our cells, tissues and organs are being bombarded by radioactivity according to the energy of each type of radioisotope and its effective half-life.
- The physical half of Iodine-131 is relatively short, but Cesium-137, which accumulates in muscles and other tissues, has a half-life of 30 years. The effective half-life of Cesium-137 is 110 days, still a long time.
- We eat several types of food at each meal and we drink beverages, several times a day, day in and day out. Since each type of food we eat and each liquid we drink is contaminated with radioactivity, each time we eat or drink it, the cumulative dose should be taken into account for all the foods and liquids we ingest for every day they are taken into our bodies. (Note: water from covered wells, springs and reservoirs may not be contaminated.
- Neither UC Berkeley nor any other entity is testing for all radioactive materials arriving via the jet stream from the Fukushima plant in Japan. Berkeley is testing only for Cesium-124, Cesium-137 and Iodine-131, Iodine -132, and Tellurium-132. The EPA tests for far fewer types. Other unidentified radioactive particles are also getting into our food, water, soil, animals, homes and businesses.
- Radioactive particles from Japan have been scattered over the earth for five weeks, with no end in sight. These radioisotopes are accumulating in our bodies, soil, water, crops, animals, oceans and atmosphere faster than they are being removed through decay and other processes.
- Due to the large amount of contaminated grasses and contaminated water consumed by grazing animals and the concentration of radioactivity in milk, milk and other products of grazing animals contain more elevated levels of radionuclides than other foods.
- We cannot shield ourselves from radiation in food and water (or air) . We must take these substances into our bodies to survive. We usually have a choice about flights; whether to take them at all, or to travel by train or car instead.
There are many more sources of radioactive particles from Fukushima and routes of entrance into our bodies than are noted above or tallied.
- In addition to eating and drinking them, we are inhaling these same radioactive particles, adding to the internal radiation dose. Hot showers aerosolize the particles, so they are inhaled from this source as well. Sweeping and vacuuming redistribute settled particles into the air adding to the particles that are inhaled. Vacuums with HEPA filters may filter out some particles.
- Some types of radioactivity penetrate our skin, or enter our bodies through cuts or other skin openings
- The continuing contamination from Fukushima effectively distributes radioactive particles onto every surface and object in our lives, either directly or indirectly. For example, we track these particles into our homes, businesses and other destinations on our shoes. Our pets are contaminated. We take showers and wash our clothes and dishes with contaminated water. We touch contaminated items with our hands and then put our fingers or the contaminated items into our mouths. The contaminated objects themselves may emit radiation, albeit tiny amounts.
Excerpt:
Radionuclides, once deposited by rainwater or air onto the ground, will find their way through the ecosystem. We are already tracking its path from rainwater to creek runoff to tap water, but we would also like to monitor how much these isotopes that make their way into our food. For example, how much gets taken up by the grass and eventually winds up in our milk?
We have been collecting produce that is as local as possible to test for the radioactive isotopes. We might expect different kinds of plants to take up different quantities of cesium and iodine, so we are trying to measure as many different plants and fruits as we are able to. So far, we have measured grass, wild mushrooms, spinach, strawberries, cilantro, kale, and arugula. We have also measured local topsoil.
Link
Posted in Food Safety, Nuclear power disaster, Radiation health risks, Water Safety | No Comments »
April 13, 2011 at 4:14 pm By Roz Potter
From the Stuart Smith blog Link , via the Daily Kos
The revelation that natural gas drilling companies are dumping radioactive waste water into our rivers virtually unregulated was shocking enough, but now the New York Times is reporting that radioactive sludge is being used for fertilizer on our nation’s farms. You heard right: radioactive fertilizer – a direct line to the food chain.
Has the whole world gone stark raving mad? Well, if not the whole world, at least the part that handles U.S. environmental regulation.
The news that radioactive material is being used for fertilizer on the farms that produce our vegetables and milk (among other food products) should make even the most permissive pro-industry segments of the American public exceedingly uncomfortable. Radiation outside the food chain – in rivers, for example – is one level of risk, but radiation contamination in the food chain is a much more serious and insidious threat to public health.
Also see NYT articles, Here and Here
Excerpt:
Toxic Contamination From Natural Gas Wells
The New York Times collected data from more than 200 natural gas wells in Pennsylvania. Many of them are tapping into the Marcellus Shale, a vast underground rock formation. But a method being used to stimulate wells, called hydraulic fracturing, produces wastewater containing corrosive salts and radioactive and carcinogenic materials. In Pennsylvania, this wastewater has been sent through sewage treatment plants that cannot remove some of the contaminants before the water is discharged into rivers and streams that provide drinking water. The Times was able to map 149 of the wells.
Posted in Food Safety, Fraking, Radiation health risks, Water Safety | No Comments »
April 13, 2011 at 1:40 pm By Roz Potter
Editor: It appears that a number of news accounts are confusing deterministic effects with stochastic effects, creating a serious mix-up about the health risks associated with the ingestion of food and water contaminated with radionuclides.
From the Canadian Health Service, Link Excerpts from page 12:
Deterministic effects are characterized by a generally accepted minimum level of dose, or threshold, be low which they are not expected to occur, and result from the body’s in ability to cope with the death of a significant number of cells in certain tissues or organs. The severity of these effects, such as nausea, skin burns or acute radiation syndrome, increases with dose above a clinical threshold, and with few exceptions appear within days to weeks after exposure. The threshold for early observable effects such as nausea or temporary blood cell changes is about 250-500 mSv received in a short period of time (ICRP 1991).
Stochastic effects result from damage to cellular DNA, and may not show up until years after the exposure has occurred. The effects of primary concern are an increased risk of radiologically-attributable cancer in exposed persons and potential genetic disorders in their offspring. The likelihood of experiencing these effects, rather than their severity, is assumed to be proportional to dose, and it is generally assumed that there is no level of radiation, however small, that is completely free of the risk of stochastic effects.
Stochastic effects are the primary health risk associated with exposure to low doses of radiation, including those due to the consumption of contaminated food and water.
Posted in Food Safety, Nuclear power disaster, Radiation health risks, Water Safety | No Comments »
April 11, 2011 at 8:53 pm By Roz Potter
From Forbes.com blog
Excerpt:
The Environmental Protection Agency recommends reverse osmosis water treatment to remove radioactive isotopes that emit beta-particle radiation. But iodine-131, a beta emitter, is typically present in water as a dissolved gas, and reverse osmosis is known to be ineffective at capturing gases.
A combination of technologies, however, may remove most or all of the iodine-131 that finds its way into tap water, all available in consumer products for home water treatment.
Posted in Health, Radiation health risks, Water Safety | No Comments »
March 21, 2011 at 3:33 pm By Roz Potter
The Idaho Department of Environmental Quality has an informative chart on its website , that will give readers an idea of the average amount of radiation absorbed each year from food, water, natural gas powered stoves and heaters, medical x-rays and nuclear medicine procedures, proximity to nuclear power or coal fired power plants, smoking, flying in an airplane, and other sources.
There is several other nifty charts on the website including a personal yearly dose calculator.
These sources do provide welcome perspective.
Posted in Food Safety, Radiation health risks, Water Safety | No Comments »
Of Note