Estimation of ecological and radiation state of northern forest-steppe soils of Kurgan region

Monitoring of ecological and radiation state of soils of the northern forest-steppe of the Kurgan Region was carried out by specialists of FSFEI SAS “Shadrinskaya” in the period from 1993 to 2016 in seven administrative regions with the terri-tories included to the zone of radioactive pollution after the accident at “Mayak” production associa-tion. During the period from 1993 to 2016 essential decrease in the intensity of radiation background from 13 to8 μR/h was observed. In 1993-1995 the average level of radiation pollution of soils with strontium-90 was estimated as average, on caesi-um-137 as minimum. In 2016 average level of radi-ation pollution was estimated as minimum. Thus the activity of long-living isotopes of strontium-90 and caesium-137 in grain, straw and grasses se-lected in reference points on the territory of Kar-gapolsky, Mishkinsky, Shadrinsky, Shatrovsky, Shumikhinsky areas did not exceed admissible lev-els. In Dalmatovsky and Kataysky areas it the ex-cess of admissible limits according to the content of strontium-90 in the grasses growing in the flood-plain of the Techa River in which waters after the accident the dumping of radioactive materials took place was revealed. The content of strontium-90 made 7.6-17.1 maximum concentration limits. In soils the ratio of Sr/Cs made 0.4-2.5 units whereas upon transition to grasses this ratio increased to 118.6-309.1. High affinity of strontium-90 to bioge-nous element to calcium leads to its essential ab-sorption by plants. So, the coefficient of accumula-tion of caesium-137 did not exceed 0.075 whereas for strontium-90 this indicator varied in the range from 5.893 to 9.958.