1. School of Pharmacy, Lanzhou University, Lanzhou, China;
2. Department of Ecology and Environment of Gansu Province, Lanzhou, China;
3. Gansu Provincial Maternity and Child-care Hospital, Lanzhou, China;
4. Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China;
5. School of Information Science & Engineering, Lanzhou University, Lanzhou, China