IODINE IN DRINKING WATER IN THE NORTHERN REGION OF GHANA: ITS RELATIONSHIP TO IODINE DEFICIENCY DISORDERS

Abstract

Iodine (I) levels in various water sources of the Northern Region of Ghana are related to the underlying geology: the Basement Complex and the Voltaian sediments, and also the occurrence of goitre. Iodine is highest in the underground water (<0.3 to 9183 mg/L). The mean I concentration measured in the Region was 42 mg/L, which is less than 30% the recommended daily requirement for an adult male. Iodine is higher in the groundwaters from the Voltaian sediments (especially the Middle Voltaian) than the Basement Complex. The observed trend was Basement Camplex<Lower<Upper<Middle Voltaian. The explanation for this trend was due to the relatively more argillaceous sediments in the Middle Voltaian than the others. The rate of endemic goitre in the region underlain by the Lower Voltaian was explained by low I in the water sources. Some factors were suggested to explain the problem of I deficiency in the study area which include: (i) limited sources for I supplements to the people other than water; (ii) low I content from local foodstuffs produced from soils impoverished in I; (iii) I is not available to the body due to the presence of goitrogens; (iv) I content taken in is low and is not retained long enough in the body because it is bioacumuIative: that is, it is readily excreted through sweat, urine. or faeces; and (v) probably the local food sources and vegetables may contain anti-thyroid agents.