Submitted on: 30 December 2008.
Revised on: 28 January 2009.
Accepted on: 03 February 2009.
Revista Internacional de Contaminacion Ambiental
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Submitted on: 10 September 2013.
Revised on: 28 September 2013.
Accepted on: 08 October 2013.
Revista Internacional de Contaminacion Ambiental
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http://reply.papertrans.cn/3/271/27005/27005-35.png
http://reply.papertrans.cn/3/271/27005/27005-36.png