Geologic environments and human health in China. (Guest Editorials).

Natural geologic environments in China affect human health in a variety of ways through interactions between geochemical, hydrologic, and biologic processes and human activities. Numerous national-scale cases serve as examples, including correlations between the distribution of Keshan and Kaschin-Beck diseases (both thought to be associated with nutritional deficiencies) and the northeast-southwest-oriented low selenium belt in temperate forests and forest-grass regions (Fang 2002). The areas of fluorine-related endemic ailments, which occur in one-half of China's 2,171 counties, have a distribution that tends to match that of regions with high-fluorine rocks, aquifers, springs, and coals (Cai 1995).

Environmental factors such as climate, along with the human activities and cultural customs, can also enhance health impacts in areas with high natural background concentrations of hazardous geochemical compounds. The serious arsenicism in parts of Guizhou Province is related not only to the high arsenic content (as high as 35,000 ppm) in local Permian coal deposits but also to the cold and humid winter conditions on the high plateau in the western part of the province. Residents there heat their homes by burning locally obtained coal in open fires. Because most houses do not have chimneys, the arsenic-containing smoke goes directly into the living areas. Moreover, residents often hang corn and chili peppers over the fires in their homes to dry them for later use. This practice can transfer the arsenic from the coal coating and permeating the peppers and corn by sublimation, and then of course entering the body when the food is eaten (Zheng 1996). Naturally occurring radioactive radon gas is also a health problem in some regions of China. In these areas the radon, which has been linked to lung cancer, can enter homes either through direct emission from rocks or soils, or through bricks that have been made from radon-rich mining waste.

Some health problems are related to special landscape settings. Tens of millions of people in China rely on karst aquifers for drinking water. These aquifers are formed by dissolution of soluble limestone bedrock, which forms caves, sinkholes, and other related features; the groundwater resources that these aquifers contain are vulnerable to contamination. Such problems are widespread: in southwest China, limestone covers an area of more than 500,000 [km.sup.2]. Because of karst development in these areas, water resources in the region are based on nearly 3,000 underground streams, with a total length of some 14,000 km and total discharge of more than 100 billion L/day. In these areas, major land resources distributed above the underground streams use these streams as drainage systems. The types of land use in the area have the potential to create contamination problems; for example, urbanization, mining, farming, manufacturing, or highway construction can all bring about degradation of groundwater quality and associated human health problems. In Shanxi Province, which is the major energy base of China because of its rich coal resources, extensive coal deposits overlie large carbonate rock karst aquifers, the most important source of local water supplies. The pollution of large karst springs by sulfur, lead, cyanide, and other contaminants from coal and related chemical industries results in serious health concerns. Iodine deficiency symptoms also occur often in limestone regions.

In total, high fluorine, low iodine, low selenium, and low molybdenum symptoms affect about 300 million people in China (Fang 2002). In an effort to address such diseases with biochemical origins, a special leading committee under the State Council, with the involvement of seven ministry-level institutions, was established in 2000. Special programs addressing particular problems, such as the Program to Dispel Iodine Deficiency Symptoms in China, have been implemented. To aid in the planning of governmental actions, an Atlas of the Ecological Environmental Geochemistry of China has been published (Li and Wu 1999). The 209-page atlas contains 107 maps, including the following national maps: 24 geochemical maps showing elemental distributions (Al, As, B, Ca, Cd, Co, Cr, Cu, F, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, Ti, V, and Zn); 8 maps showing available elements in soil (B, Cu, Fe, Mn, Mo, Zn, K, and P); 9 dietary intake maps (Ca, Cu, Fe, K, Mn, Na, P, Se, and Zn); 14 maps showing elements measured in human hair (Al, As, Ca, Co, Fe, Hg, K, Mo, Ni, Se, Sr, Ti, V, and Zn); and 6 maps showing mortality of liver, stomach, and esophageal cancers for both men and women (Li and Wu 1999).

Many practical steps have been taken to prevent and cure the most serious of these environmentally caused health problems. In certain regions of Huhhot City, Baotou City, and Bayannur Meng Prefecture, Inner Mongolia Autonomous Region, the arsenic content in groundwater is much higher than the national standard. As of 2000, this had affected about 300,000 people. A new project has been launched--the Changing Source of Water Supply to Prevent Arsenicism--at a cost of 15 million yuan (RMB). During the project's first phase in 2001, about 68,600 people from 207 villages were able to obtain safe drinking water. Another 63,000 people will have safe drinking water when the second stage is finished later in 2002 (Li 2002). International cooperation in biogeochemical research, prevention and cure of geochemically related disease, better land use planning and management, and increased environmental protection are already improving the living conditions and health of the people in these areas.

I thank Chris Groves (Western Kentucky University, Bowling Green, KY) for valuable assistance in translating the editorial into English.

Daoxian Yuan, a hydrogeologist and environmental geologist, is the director of the Karst Dynamics Laboratory, Ministry of Land and Resources. He is a member of the Chinese Academy of Sciences and the Editorial Board of Environmental Geology, and he is project co-leader of the United Nations Educational, Scientific and Cultural Organization/International Union of Geological Sciences-supported International Geological Correlation Program (IGCP 448), World Correlation of Karst Ecosystems (2000-2004).

Daoxian Yuan
Karst Dynamics Laboratory
Ministry of Land and Resources
Guilin, People's Republic of China
E-mail: [e-mail]

REFERENCES AND NOTES

Cai H. 1995. Study on Modern Environmental Hygiene [in Chinese]. Beijing:People's Health Press, 665-698.

Fang K. 2002. Sustainable development and transformation of the functional structure of geological work [in Chinese]. Geol Bull China 21(3):113-117.

Li J, Wu G, ads. 1999. Atlas of the Ecological Environmental Geochemistry of China. Beijing: The Geological Publishing House.

Li Z. 2002. More than 60 thousand people in Inner Mongolia get out from the threat of arsenic. Guilin Evening News (China) 1 July: 2.

Zheng B, Yu X, Zhang J, Zhou D. 1997. Environmental geochemistry of coal and endemic arsenicism in southwest Guizhou, China [Abstract]. In: Abstracts of the 30th International Geological Congress, Vol. 3, 4-14 August 1996, Beijing, China; 410.