The change of

131

I content in sheep-tissue in Xinjiang after the accident at Chernoby USSR was studied with a radiochemical method. The results showed that

131

I level was increased from 7th May in sheep-tissue and reached its maximum on 20th May in thyroid. The effective half-life of

131

I in thyroid

blood

muscle and contents in stomach were 7.2d

6.7d

6.7d and 5.1d respectively. The specific activities of

131

I in grass

thyroid

blood

muscle and contents in stomach showed linear correlations.

The

131

I content in thyroid for the folded sheep was only 1.7 percent of that for the grazed sheep during the polluting period. The effective dose equivalence for adult to the

131

I release from Chernobyl was 14.0

µ

Sv in Urumqi and 3.8 µSv in Xinjiang.