1. School of Environmental Science and Engineering, Tiangong University, No. 399 Binshui West Road, Xiqing District, Tianjin 300387, China
2. Department of Civil and Environmental Engineering, Shantou University, No 243 Daxue Road, Shantou, Guangdong Province, 515063, China
3. Institute of Agricultural Product Quality Standard and Testing Research, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, Tibet 850032, China