Iodine is an essential trace element for humans and animals. A lack in the diet can
lead to iodine deficiency disorders (IDD) the most common manifestation being
goitre, an enlargement of the thyroid gland in the neck. Infants born to severely Ideficient
mothers may suffer cretinism and I-deficiency is the world's most common
cause of preventable mental retardation. In many countries this problem has been
tackled successfully using medical interventions such as the iodination of table salt.
Xinjiang Province in northwest China is a remote desert region where goitre and
cretinism have been reported for many years. People in this region do not like the
taste of iodised salt and prefer to use local rock-salt with very low concentrations of
iodine. As an alternative treatment, previous investigators added potassium-iodate to
irrigation waters in an attempt to increase the I-concentrations of crops and animals in
the food supply and the I-status of the population. Initial successes were reported but
the long-term effectiveness of the method had not been tested. The present study aims
to assess environmental controls on iodine uptake into the food chain and in Xinjiang
had the opportunity to study three contrasting area
