Is Gippsland environmentally iodine deficient? Water iodine concentrations in the Gippsland region of Victoria, Australia.

OBJECTIVE   This paper provides evidence of environmental iodine deficiency in the Gippsland region. DESIGN   Quantitative study; water samples were collected from 18 water treatment plants and four rain water tanks across Gippsland and water iodine concentrations were measured. SETTING   Gippsland region of Victoria, Australia. MAIN OUTCOME MEASURES   This paper reports on the iodine concentration of drinking water from sources across Gippsland and examines the contribution of iodine from water to the Gippsland diet. This study also briefly examines the relationship between the concentration of iodine in water and distance from the sea. The cut-off value for water iodine concentrations considered to be indicative of environmental iodine deficiency is <2 µg L(-1) . RESULTS   The mean iodine concentration of water from 18 Gippsland water treatment plants was 0.38 µg L(-1) and would therefore make negligible difference to the dietary intake of iodine. This finding also falls well below the suggested dietary intake of iodine from water estimated by the 22nd Australian Total Diet Study. Our study found no linear relationship between the water iodine concentration and distance from the sea. CONCLUSION   As Gippsland has environmental iodine deficiency there is a greater probability that people living in this region are at higher risk of dietary iodine deficiency than those living in environmentally iodine sufficient regions. Populations living in areas known to have environmental iodine deficiency should be monitored regularly to ensure that problems of iodine deficiency, especially amongst the most vulnerable, are addressed promptly.