China is a very large developing country covering vast territories and having a complex natural environment. It has an enormous population and numerous endemic diseases. The total population of China is 14 x 10(8) of which 3 x 10(3) live in endemic disease-affected areas and 0.48 x 10(3) suffer from these diseases. The distribution of the endemic diseases has obvious geographical characteristics. Among the most harmful and widely distributed of the endemic diseases are Kaschin-Beck disease, Keshan disease, iodine deficiency, endemic fluorosis and hepatic carcinoma. The geographical environments have a close relationship to endemic diseases and are influenced by climate, geology, landform, soil, food and drinking water. Drinking water is the key issue, since polluted water, or water lacking in or having an excess of certain minerals and elements, as well as water containing certain organic components, has been shown to be harmful to human health. Research has shown that some diseases can be reduced or eliminated by paying attention to the way drinking water is obtained, as well as by improving the nutritional values of the food by eliminating negative components. Fifty years of research has already gone into this subject and there is still much research to be done. This paper puts forth a model of health problems related to geographical environment and the importance of continued research in this field.

On the basis of the soil environment investigation in Da′an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade Ⅳ and Ⅴ. And the ratios of soil samples grade Ⅳ and Ⅴ in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da′an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate results and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.

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In the past 40 years, the deserti®cation rates have reached between 0.81 and 1.