Transport of the radioisotopes iodine-131, cesium-134, and cesium-137 from the fallout following the accident at the Chernobyl nuclear reactor into cheesemaking products

A Simple and Rapid Method for Reducing Radiocesium Concentrations in Wild Mushrooms ( Cantharellus and Boletus ) in the Course of Cooking

Many species of mushrooms are known accumulators of radioactive cesium (¹³⁷Cs and ¹³⁴Cs). Even years and decades after major nuclear accidents, especially those at Chernobyl and Fukushima, mushrooms exhibit high concentrations of these radionuclides. We investigated a simple method for reducing the activity of radiocesium in wild mushrooms (chanterelles, Cantharellus cibarius ; and boleti, Boletus edulis ) during cooking. The juice generated while cooking mushrooms contains a relatively high fraction of the total cesium. The amount of juice can be increased by washing the mushrooms with water prior to cooking. By removing the juice, up to 29% of the radiocesium can be easily removed from chanterelles. Because boleti have a lower affinity for cesium, activity levels were lower in boleti than in chanterelles. The fraction of radiocesium in the juice was lower in boleti than in chanterelles.

An overview of Fukushima radionuclides measured in the northern hemisphere

The Great East Japan Earthquake and tsunami on March 11, 2011 resulted in the tragic accident at the Fukushima Nuclear Power Plant (NPP) and subsequently uncontrolled release of radioactive contaminants into the atmosphere. This review article attempts to compile and interpret data collected by various national and international monitoring networks in response to the Fukushima releases across the northern hemisphere. The majority of the releases occurred during the period March 12-22 with a maximum release phase from March 14-17, 2011. The radioactivity released was dominated by volatile fission products including isotopes of the noble gases (xenon and krypton), iodine, cesium, and tellurium. The radioactive gases and particles released in the accident were dispersed over the middle latitudes of the entire northern hemisphere and for the first time also measured in the southern Hemisphere. Isotopes of iodine and cesium were detected in air, water, milk and food samples collected across the entire northern hemisphere. Elevated levels of fission products were detected from March to May 2011 at many locations over the northern hemisphere. This article focuses on the most prevalent cesium and iodine isotopes, but other secondary isotopes are also discussed. Spatial and temporal patterns and differences are contrasted. The activity ratios of (131)I/(137)Cs and (134)Cs/(137)Cs measured at several locations are evaluated to gain an insight into the fuel burn-up, the inventory of radionuclides in the reactor and the isotopic signature of the accident. It is important to note that all of the radiation levels detected outside of Japan have been very low and are well below any level of public and environmental hazard.

12. Chernobyl's radioactive contamination of food and people

In many European countries levels of I-131, Cs-134/137, Sr-90, and other radionuclides in milk, dairy products, vegetables, grains, meat, and fish increased drastically (sometimes as much as 1,000-fold) immediately after the catastrophe. Up until 1991 the United States imported food products with measurable amounts of Chernobyl radioactive contamination, mostly from Turkey, Italy, Austria, West Germany, Greece, Yugoslavia, Hungary, Sweden, and Denmark. These products included juices, cheeses, pasta, mushrooms, hazelnuts, sage, figs, tea, thyme, juniper, caraway seeds, and apricots. In Gomel, Mogilev, and Brest provinces in Belarus 7-8% of milk and 13-16% of other food products from small farms exceeded permissible levels of Cs-137, even as recently as 2005-2007. As of 2000, up to 90% of the wild berries and mushrooms exceeded permissible levels of Cs-137 in Rovno and Zhytomir provinces, Ukraine. Owing to weight and metabolic differences, a child's radiation exposure is 3-5 times higher than that of an adult on the same diet. From 1995 to 2007, up to 90% of the children from heavily contaminated territories of Belarus had levels of Cs-137 accumulation higher than 15-20 Bq/kg, with maximum levels of up to 7,300 Bq/kg in Narovlya District, Gomel Province. Average levels of incorporated Cs-137 and Sr-90 in the heavily contaminated territories of Belarus, Ukraine, and European Russia did not decline, but rather increased from 1991 to 2005. Given that more than 90% of the current radiation fallout is due to Cs-137, with a half-life of about 30 years, we know that the contaminated areas will be dangerously radioactive for roughly the next three centuries.

Processes that contribute to radiocesium decontamination of feta cheese

In a series of experiments, the transfer of radiocesium from ovine milk to feta cheese was investigated through modifications of the standard cheese making procedure. All variations explored showed no significant change in the percentage of radiocesium transfer and the milk-to-cheese transfer coefficient was determined as f=.79 plus/minus .04 L.kg-1. It is concluded that cesium, like the rest of the alkali metals, remains in the water phase and thus follows very closely the distribution of moisture into the products of cheese making. The possibility of radiocesium decontamination of mature feta during the customary storage of the product in brine was also explored in a second series of experiments. The theoretical model employed in the analysis of cesium transport from feta to brine is presented in the Appendix to this paper. Predictions of the model were validated by experiments. A procedure is thus proposed for decontaminating mature feta during storage through successive replacements of the storage medium. Nomograms are presented for the determination of the optimum time interval between changes of the brine and the radiocesium concentration remaining in the feta. Changes in the properties of the product induced by the proposed treatment were also investigated with respect to composition, taste, and overall quality.