Jody Berg Dept. Earth and Physical Sciences Western Oregon University The Earth’s crust is comprised of rock materials, which in turn is composed of inorganic silicate minerals. Rock material decomposes at the Earth’s surface to form regolith via chemical and physical weathering. Regolith forms the basis of soil and the fundamental framework for life in the critical zone, at the interface of the hydrosphere, atmosphere, and geosphere. Soil forms via physical, chemical, and biological transformations over time. As a result of pedogenic process, elements are released into surface and groundwater, and subsequently become available as part of macro- and micro- nutrients in the food chain with plants at the foundation. Essential macro-elements derived from the lithologic environment include Ca, Mg, Na, Cl, K, P, and S. Lesser abundant, but still important nutrients include Mn, Fe, Co, Cu, Zn, and Se. Deficiencies and surpluses of nutrients in the food chain effect physiological function of both animals and humans. Thus an understanding of geological variables in terrestrial ecosystems is essential for regional public health studies. This paper examines the effects of Earth materials and related near- surface processes on human health. 4 : Earth Materials at the Foundation : Geologic Factors that Effect Human Health 4 : Earth Materials at the Foundation : Geologic Factors that Effect Human Health Jody Berg, Western Oregon University Faculty Sponser : Steve Taylor, PhD INSERT YOUR ORGANIZATION’S LOGO HERE Soil is the key element in the transport of abundant essential and trace minerals to not only humans but animals as well. With looking at the soil in a particular area it is possible to establish whether or not the soil in that area contains the minerals and in what amount. There are ways to avoid deficiencies of elements and toxicity. This is to look at the plants growing in such areas and make an observation on whether they contain the concentration in the edible part or other parts. With looking at soil content and plant life it is possible to avoid deficiencies and toxicity in human life. Break down of rocks and formation of sediment (figure 1) : Chemical weathering Mechanical and Physical weathering Regolith is formed as a result of the decomposition of rocks. When regolith is joined by organic material it becomes soil. Soil represents a natural mixture of : Inorganic mineral material Living and dead organic substances Air & water. (Komatina) Cadmium and Lead are the elements in contaminated soil that are said to introduce the greatest health risks. In London there is a great exposure to lead in garden soil. This is because of the lead based paint that was widely used. Although the lead infiltrates the plants it doesn’t effect them. Most humans are effected by lead via dirt more so than the plants themselves. This is contributed to eating the dirt accidently. (figure 5 shows an effect of lead poisoning. In China paddy rice crops are grown near a river. This river and the paddy crops themselves are exposed to a high rate of cadmium. When the paddies are dried out the Cadmium ion is absorbed at fast rates. When people eat this they are exposed to cadmium toxicity. It mostly effected elderly women who had had many children. The disease is called itai-itai disease. The average concentration of cadmium found on the paddies was more than 10x the amount that should be taken in per day. (Alloway) (figure 4) Introduction Soil Forming Process Alloway, 2005, Bioavailability of Elements in Soil, in Selinus, 2005 Komatina, 2004, Chapter 2 – Overview Geological Factors that Effect Human Health NRC, 2007, Chapter 2 – Earth Processes and Human Physiology NRC, 2007, Chapter 6 – Earth Perturbations and Public Health Impacts Skinner, 2005, Mineralology in Bone, in Selinus, 2005 Case Studies Conclusion References Figure 2. Soil Horizons Abstract Contact Soil plays an important role in the transport of minerals. Soil is formed from physical/chemical weathering of rocks to regolith. When regolith interacts with plants, microorganisms, and soil fauna it becomes soil. (Alloway). The soil type in an area will dictate whether it will have abundant essential minerals or trace essential minerals. Both of these groups of minerals are essential for life on Earth. An abundance of a specific mineral in an area could lead to toxicity in the human population and the animal/plant population. This is a large concern for trace minerals which are ok at small and moderate concentrations, yet at higher concentrations will lead to toxicity in humans. The lack of trace minerals all together though will lead to a deficiency. This could be due to the fact that they are essential to the overall health of people. Both the essential abundant minerals and essential trace minerals are important to the over function and wellbeing of humans and animals alike. With an increased amount of mineral intake, or lack there of, it will lead to health problems. Figure 1 : Rock Cycle : shows the effect of both weathering processes. Once soil produces plants it is capable of concentrating various chemical elements. (Komatina) The plants that live in the soil are able to lift elements out of the lower horizons and transport them to the upper horizons. (P, S, Ca, K, and many of the trace elements.) (Komatina) Horizon A : rich in organic matter & organisms. Accumulation of humus & many elements in upper part. Horizon B : via infiltration of water, clay & iron minerals accumulate in it. Elevated content of Cu, Ni, Zn, Pb, & other. Horizon C : represents loose and partially weathered rock mass. (Komatina) Figure 2 represents the different soil horizons and what is commonly found in them. Case Studies Acute deficiencies of trace elements in plants can result in : Visible symptoms of stress Chlorosis (figure 3) Reduced dry matter growth & yield. India is a large country which the soil suffers from mineral deficiencies. 45% deficient in zinc, 33% boron, 8.3% iron, 4.5% manganese, & 3.3% copper. This is because the soil in this particular region can not support some essential elements.(Alloway) Figure 3 : Iron deficiencies in plants will turn the leaves this yellow color. Figure 4 : A person suffering from itai-itai disease. Figure 5 : An albatross suffering from droopwing, which is an effect of lead poisoning.