ABSTRACT

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17. Geologic Occurrence of Mercury and Iodine
Health Concerns in the 21st Century
Trista Ten Clay ES473 Environmental Geology Earth
and Physical Sciences Dept. Western Oregon
University
ABSTRACT The emerging field of medical geology
provides a unique perspective to the many health
effects caused by iodine and mercury in the
natural environment. Iodine in small quantities
is an important element that helps the body
retain and use water, making it vital to human
and animal health. Overexposure and
underexposure of iodine may cause very serious
and sometimes deadly effects. In contrast,
mercury is a toxic metal that is tolerable to
physiological function in small amounts but the
process of bioaccumulation and incremental
increases in the food chain creates a threat of
overexposure. Case studies are examined to
understand the geologic controls on the mercury
and iodine occurrence. Examples include a goitre
occurrence in Sri Lanka, excessive iodine
accumulation in southeast Asia, mercury toxicity
in the gold fields of Kenya, and bioaccumulation
potential in regional food supplies.