Excretion of radiocesium in reindeer - effect of supplements of potassium and bentonite

Abstract

Six reindeer calves were fed feed containing supplements of potassium and/or bentonite. The purpose was to see in what respect these supplements could affect the excretion of radiocesium. The reindeer started with high levels of radiocesium in their bodies. They were fed feed with no supplement, supplement of 15 g K/day or supplements of 15 g K + 80 g bentonite/day. There were big differences between reindeer within the groups. The half times for radiocesium were shorter for reindeer that had received K and K + bentonite (11-13 days) than for those without supplements (15 - 18 days). During the next part of the experiment the reindeer were fed lichens, and had an intake of 20 kBq Cs-137/day. The increase of radiocesium in blood was highly affected by supplements of bentonite. Two reindeer that had not received any bentonite had, after three weeks of feeding, nearly 10 times the radiocesium in blood as did those who had got supplements (23 or 46 g/day) of bentonite. Excretion of radiocesium was significantly higher in those reindeer receiving bentonite. The absorption of cesium from the food was calculated to 15 -25% for reindeer receiving bentonite and to ca 70% for reindeer that got no supplements. The experiment was completed with a period of feeding with no intake of radiocesium. The animals were given supplements of bentonite at two levels (23 g and 46 g/day). The excretion of radiocesium in faeces was higher for the group receiving the higher supplement of bentonite. Half times for radiocesium in blood was 13-14 days for the group that was given less bentonite and 10- 11 days for those receiving the higher amount.

Utsondringen av Cs-137 hos renar vid utfodring med foder innehållande varierande mångd bentonit respektive kalium.

Abstract in Swedish / Sammanfattning: Sex renkalvar utfodrades med foder innehållande tillsats av kalium och/eller bentonit i syfte att undersoka dessa tillsatsers effekt på utsondringen av radioaktivt cesium. Renarna borjade forsoket med en hog halt av radiocesium i kroppen. De utfodrades med foder utan tillsats, tillsats av 15 g K/dag respektive tillsats av 15 g K + 80 g bentonit/dag. Skillnaden mellan renar inom grupperna var stora. Halveringstiden for radioaktiv cesium i blodet blev dock kortare for de renar som fått K eller K + bentonit (11-13 dagar) jåmfort med de renar som inte fått något tillskott (15 - 18 dagar). Under nåsta del av forsoket fick renarna lav, som gav ett intag av Cs-137 på 20 kBq/dag. Okningen av cesium i blodet påverkades kraftigt av bentonittillskott. Två renar som inte fått något tillskott av bentonit hade efter tre veckor nåstan 10 gånger hogre koncentration av Cs-134+137 i blodet som de som fått 23 respektive 46 g bentonit/dag. Utsondringen av radiocesium var betydligt hogre hos de renar som fått bentonit. Absorptionen av Cs-137 från fodret beråknades till 15 - 25% for de renar som fått bentonit och ca 70% for renar utan tillskott. Forsoket avslutades med helutfodring (inget intag av radioaktivt cesium). Renarna fick då tillskott av bentonit på två olika nivåer (23 g respektive 46 g per dag). Utsondringen av Cs-137 i track var i genomsnitt hogre for den grupp som fått mer bentonit. Halveringstiden for Cs-134+137 i blod var 13 - 14 dagar for de renar som fått den mindre mångden bentonit och 10-11 dagar for de som fått den storre mångden.