1. Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China
2. Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China
3. Program for the Environment and Sustainability, Department of Occupational and Environmental Health, School of Public Health, Texas A&M University, College Station, Texas 77843, United States