China, southwestern

Other natural sodium sulfate brines of commercial importance are found in dry lake beds of southwestern Saskatchewan, Canada (70) Laguna del Ray in Coahuila, Mexico the Gulf of Kara-bogaz of the former USSR and western China. 

Lead has been found to reside mainly in the carbonate and the residual fractions in arid soils. In Californian soils, most of the Pb is in the carbonate fraction (55%), compared to 20% in the residual fraction (Sposito et al., 1982). In Israeli arid soils, Pb is predominately in the residual and the crystalline Fe oxide bound fractions (Han and Banin, 1999). In the delta of the Guadalquiver River of Southwestern Spain, Pb is primarily present in the Fe-Mn oxide bound fraction, followed by the carbonate fraction, while the organic and the exchangeable fractions are small (Ramos et al., 1994). In uncontaminated arid soils of China, Pb is mainly in the residual fraction, followed by the carbonate and the oxide bound fractions (Jin et al., 1996). 

CRMs were inserted into the approximately 3000 samples in the 76-element geochemical mapping pilot project in southwestern China. The RSD% of these determinations and the certified values are listed in Table 3. All the RSD are less than 25% and the analytical data are considered accurate. Data accuracy had also been subsequently justified from the mapping results. 

Zhang, J., Ren, D., Zhu, Y. et al. (2004) Mineral matter and potentially hazardous trace elements in coals from Qianxi Fault Depression Area in southwestern Guizhou, China. International Journal of Coal Geology, 57, 49-61. 

Zheng, B., Ding, Z., Huang, R. et al. (1999) Issues of health and disease relating to coal use in southwestern China. International Journal of Coal Geology, 40(2-3), 119-32. 

Table 17.2 Partial geochemistry of selected coals from southwestern Guizhou Province, PR China...

A survey has shown that the city of Enshi, Hubei Province, China, has three major Se-enriched deposition periods including the early Cambrian, Late Ordovician, and Permian periods. The stone coal formed during the first two periods has a low Se content of 30 pg g, which is similar to the stone coal formed in Early Paleozoic in Southern Shaanxi. However, the black shale series formed in the Permian period have a Se concentration that is at least threefold higher than that of the former two. There is a cross-cutting low-Se area with brown soil series from northeastern to the southwestern China including more than 10 provinces. Approximately 72% Chinese are deficient in Se, while there are about 1.5 billion people living in Se-deficient areas worldwide (Banuelos, 2009). 

Sodium carbonate bearing deposits and brines exist around die world. Locations are known in die United States, China, Turkey, Bolivia, Brazil, Venezuela, Mexico, India, Pakistan, USSR, Kenya, Australia, and Botswana (14—20). The overwhelming majority of natural ash production comes from die Green River Basin in southwestern Wyoming. Significant amounts are also produced at Searles Lake in California lesser amounts at Lake Magadi in Kenya. Minor quantities are reportedly produced in Pakistan, die USSR, and China and small amounts of impure trona come from Owens Lake, California. A plant is currently under construction to recover soda ash from brine at Sua Pan, Botswana. Each deposit has its own distinctive characteristics and each requires different processing techniques. 

Luo SQ, Liu XZ, Wang CJ. 1992. An investigation of crocidolite contamination and experimental study in southwestern China. J Hyg Epidemiol Microbiol Itmmmol 36(2) 223-224. 

Wu, F. C., and Tanoue, E. (2002). Tryptophan in sediments and lakes from the Southwestern China Plateau. Chem. Geol. 187, 139-149. 

Many parts of the world experience monsoons to some extent. Probably the most famous are the Asian monsoons, which include the distinctly different monsoons that affect India, north China, and Japan, and south China and southeast Asia. Monsoons also affect portions of central Africa, where their rain is critical to supporting life in the area south of the Sahara Desert. Lesser monsoon circulations affect parts of the southwestern United States. These summer rainy periods bring much needed rain to the dry plateaus of Arizona and New Mexico. 

The crested mynah Acridotheres cristatellus) is native to southern China and Taiwan. However, it has been introduced elsewhere, and is the c ily mynah to breed in North America. The crested nrynah has been introduced to the city of Vancouver on the southwestern Pacific coast of Canada. Although its pcpulations there have remained small, the crested nrynah continues to breed in that area. 

Zhao D. and Xiong J., 1988. Acidification in Southwestern China. In Acidification in Tropical Countries, Rodhe H. and Herrera R. (Eds.), John Wiley Sons Ltd, 1988, 317-346. 

---