GEOLOGICAL CONTRIBUTIONS TO BIOLOGICAL SYSTEMS: THE PEACE CORPS CONNECTION

Biochemical research has shown that the human body utilizes at least 40 elements in metabolic reactions and tissue structures. These nutrients are mobilized from rocks and minerals into humans via consumption of food and water. In countries lacking broad food distribution systems, such as Tanzania, locally produced food should supply these nutrients. Lacking these, health generally suffers. Conversely, health can be affected by toxic concentrations of elements excessively bioavailable from mineral sources or stored in the body to deleterious concentrations. Examples are fluoride excess affecting human teeth around volcanoes such as Mt. Kilimanjaro, and uranium excess affecting human kidneys in northern New Mexico.

During the early 1960s, Williamson Diamonds Ltd. prospected in Tanzania for 15 chemical elements having economic importance. The data set was released to the Geological Survey of Tanzania (GST), and in 1964, GST accepted Peace Corps Volunteer geologist Robbins to analyze it for geologic information and potential trace element anomalies. Working with these data, enhanced by later field studies, she concluded that rocks and minerals recycle as nutrients for organisms throughout time. Subsequently, Robbins applied this hypothesis to USGS research on petroleum prospecting using phosphate availability in Oklahoma and Virginia, and on Cu uptake in Precambrian to modern food webs that include indigenous populations in the Lake Superior region.

In 1986, GST geologist Momburi examined the same and later data sets, Robbins’ reports and publications, and reached similar conclusions. He became concerned over the potential medical aspects of missing trace elements and focused on micronutrient malnutrition, a field that correlates nutritional deficiencies with geology. In Tanzania, he was able to correlate the lack of iodine in granitic rocks of the Southern Highlands with the occurrence of physical and mental deficiencies, and the lack of iron in the Coastal Belt limestone terrains with anemic populations.

Our collegial interchange, facilitated by the Peace Corps, has benefited the US, Tanzania, and science. This work led us both to the emerging field of Geology and Health/Medical Geology/Geomedicine, thereby applying geological research to the area of public health.