Effective and ecological half-lives of 137Cs in cow’s milk in alpine agriculture

Abstract

In the mountainous "Hohe Tauern" region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer factors and long-lasting (137)Cs contamination levels in milk--the main product of seasonal agriculture at elevated altitudes--are characteristic features. The decrease in (137)Cs concentration in milk measured since 1988 turned out to be best described by one or two effective half-lives. For the period from 1993 to 2007, which can be modelled with one effective half-life for all sites, effective half-lives between 3.7 and 15.0 years (ecological half-lives: 4.3-29.9 years) were obtained. The effective half-life increases with mean altitude of the investigated graze pastures, probably due to reduced migration velocities of (137)Cs and low (137)Cs half-value depths of a few centimetres in the soil.

Transfer of Radiocesium into Wild Boar Meat

“…For example, the consumption of wild boar meat by members of hunting associations is higher by nearly two orders than that of the rest of the population, exceeding sometimes more than a half of other yearly meat consumption. Ecological halflife models (Lettner et al 2009) can be used as valuable and effective tools to specify the countermeasures for contamination reduction or meat consumption regulation. Cooking or salting, including meat brining can take part in such countermeasures (Dvořák at al.…”

Environmental Pathways of Radionuclides to Animal Products in Different Farming and Harvesting Systems

“…Activity concentration of 137 Cs in milk in such areas rose quickly in the first 2 weeks after the dairy animals began to graze these regions (around mid-June) and remained elevated until the animals were removed in the autumn. Activity concentrations of 137 Cs in milk on such meadows during summertime were several orders of magnitude higher than in milk from lowland areas and valleys, where intensive agriculture occurs (IAEA 1994;Lettner et al 2007). The 137 Cs activity concentration of milk would have remained above the intervention levels for many years if remediation options had not been applied.…”

“…Considerably longer ecological half-lives have been observed in cow's milk from alpine pastures than in cow's milk from lowland production sites. For the period 1988-2006, Lettner et al (2007)) derived ecological half-lives of 0.7-1.4 years for the fast loss component and of 9.3-12.7 years for the slow loss component of 137 Cs activity concentrations in cow's milk. Later studies showed that the T eff 1 2 / and mean altitude of the alpine meadows sites were positively correlated, with higher altitude sites having significantly longer half-lives than those at lower altitudes.…”