1. School of Environment & Energy South China Univ. of Technology; Guangzhou Guangdong 510006 China
2. Key Lab of Pollution Control & Ecosystem Restoration in Industry Clusters; Ministry of Education South China Univ. of Technology; Guangzhou Guangdong 510006 China
3. Dep. of Earth Sciences; Memorial Univ. of Newfoundland; St. John's NL A1B 3X5 Canada
4. Guangdong Key Lab. of Integrated Agro-environmental Pollution Control & Management; Guangdong Inst. of Eco-Environmental Science & Technology; Guangzhou 510650 China