BODY CONCENTRATION OF CESIUM-137 IN PATIENTS FROM WESTERN ISLES OF SCOTLAND

Objectives - To compare caesium-137 concentrations in patients from the Western Isles Health Board, Glasgow area, and other parts of the Scottish mainland, and to investigate the source of Cs-137 in patients from the Western Isles. Design - Study of hypertensive patients having electrolyte concentrations measured, including Cs-137. Interview by questionnaire of island subjects about intake of foods likely to contain radiocaesium and the source of these foods. Measurement of Cs-137 and Cs-134 in food, urine, and vegetation. Setting - Scottish mainland and Western Isles, 1979-86. All measurements before Chernobyl nuclear accident. Patients - 413 consecutive patients referred to the blood pressure unit for investigation of hypertension. 60 from the Western Isles, including 44 from North Uist; 32 from North Uist participated in the dietary analysis. Main outcome measures - Concentration of radiocaesium in the body, urine, food, and vegetation. Islanders' consumption of local produce. Results - Patients from the Western Isles had five times higher body concentrations of Cs-137 (median 2.54 (interquartile range 1.25-3.73)) Bq/gK) than did patients from around Glasgow (0.47 (0.26-0.66) Bq/gK) and other parts of the Scottish mainland (0.42 (0.24-0.71) Bq/gK). Islanders often consumed local milk and mutton, but ate local fish rarely. Cs-137 and CS-134 were present in coastal (21.6 Bq/kg CS-137, 0.25 Bq/kg CS-134) and moorland (135.9, 0.65 Bq/kg) grasses and in islanders' urine (2.01, 0.013 Bq/l). Lower concentrations (0.336, 0.004 Bq/l), were found in the urine of Glasgow controls (p < 0.001 for both isotopes). Conclusions - Islanders have excess body Cs-137 concentrations, most of which probably comes from local milk and lamb. The radioactivity is not above the recommended safety limit. The presence of Cs-134 suggests that nuclear reprocessing is the source of some of the radiocaesium.