Fen Hu1, Jianping Yang2, Ping Li2, Wei Qiu2, Xinyun Hou3, Xiao Wei4, Haiyin Wang5, Alexandra E Kauffman6, Shuo Xiao7, Zhiwei Liao8, Susana Y Kimura9, Weiwei Zheng10, Jianhai Lin11, Surong Zhu12. 1. Key Laboratory of the Public Health Safety, Ministry of Education, Department of Environmental Health, School of Public Health, Fudan University, Shanghai, 200032, China; Key Laboratory of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, Shanghai, 200032, China. 2. Inspecting Agency, Shanghai Municipal Health Commission, Inspecting Agency, Shanghai Municipal Health Commission, Shanghai, 200031, China. 3. Minhang High School, Shanghai, 200240, China. 4. Department of Occupational and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, Guangxi, 530021, China. 5. Department of Health Technology Assessment, Shanghai Health Development Research Center, Shanghai, 200032, China. 6. Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC, 29208, USA. 7. Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, 08854, USA. 8. Department of General Surgery, Renhe Hospital, Shanghai, 200431, China. 9. University of Calgary, Calgary, Department of Chemistry, AB T2N 1N4, Canada. Electronic address: s.kimurahara@ucalgary.ca. 10. Key Laboratory of the Public Health Safety, Ministry of Education, Department of Environmental Health, School of Public Health, Fudan University, Shanghai, 200032, China; Key Laboratory of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, Shanghai, 200032, China; Center for Water and Health, Fudan University, Shanghai, 200032, China. Electronic address: weiweizheng@fudan.edu.cn. 11. Inspecting Agency, Shanghai Municipal Health Commission, Inspecting Agency, Shanghai Municipal Health Commission, Shanghai, 200031, China. Electronic address: jh@hs.sh.cn. 12. Inspecting Agency, Shanghai Municipal Health Commission, Inspecting Agency, Shanghai Municipal Health Commission, Shanghai, 200031, China. Electronic address: zhusr@hs.sh.cn.
Abstract
BACKGROUND: Drinking water quality for children should be higher than adults due to both behavioral and physiological factors. Thus, to provide enough, safe, and easily accessible drinking water for children at schools, the Shanghai Municipal Government initiated a direct-drinking water project in 2013. However, there has been no study so far to assess the quality of direct-drinking water or to investigate its risk factors in Shanghai elementary and middle schools. METHODS: In the present study, we selected direct-drinking water equipment from 183 elementary and middle schools (17% of total) in Shanghai to detect the colony-forming units (CFU), residual chlorine, chemical oxygen demand (COD), and turbidity of water samples, and analyzed the risk factors of its quality using both simple and multiple linear regression analysis. RESULTS: Results showed that the CFU, residual chlorine, COD, and turbidity of direct-drinking water in Shanghai elementary and middle schools ranged from <LOD->300 cfu/mL, <LOD-0.670 mg/L, 0.090-2.710 mg/L, and 0.100-2.050 NTU, respectively. The results of simple linear regression analysis indicated that the CFU of direct-drinking water significantly increased when water temperature was between 25 and 60 °C (β = 19.862, p = 0.030), but it was decreased at 60-100 °C (β = - 16.387, p = 0.046). Additionally, the CFU was higher in elementary schools than middle schools, which was also affected by faucet type and water treatment technology (p = 0.006, 0.012 and 0.042, respectively). The residual chlorine in direct-drinking water significantly increased when there was no toilet within 10 m (β = 0.012, p = 0.045). The COD of direct-drinking water was significantly higher in rural areas and in warm water, compared to urban areas (p = 0.033) and room temperature water (p = 0.000), respectively. The turbidity of direct-drinking water was significantly higher in urban areas and water using UF/MF technology, compared to rural areas (p = 0.030) and RO technology (p = 0.009), respectively. The results of multiple linear regressions analysis drew the same conclusions. CONCLUSIONS: In order to improve the quality of direct-drinking water, the equipment should be as far away from toilet as possible and direct-drinking water should be kept at room temperature or heated at high temperature (over 60 °C). Furthermore, sanitary standards of direct-drinking water quality and relevant laws and regulations should be established and implemented as soon as possible. Our study demonstrates that it is critical to improve direct-drinking water quality and ensure the safety of drinking water in elementary and middle schools in Shanghai.
BACKGROUND: Drinking water quality for children should be higher than adults due to both behavioral and physiological factors. Thus, to provide enough, safe, and easily accessible drinking water for children at schools, the Shanghai Municipal Government initiated a direct-drinking water project in 2013. However, there has been no study so far to assess the quality of direct-drinking water or to investigate its risk factors in Shanghai elementary and middle schools. METHODS: In the present study, we selected direct-drinking water equipment from 183 elementary and middle schools (17% of total) in Shanghai to detect the colony-forming units (CFU), residual chlorine, chemical oxygen demand (COD), and turbidity of water samples, and analyzed the risk factors of its quality using both simple and multiple linear regression analysis. RESULTS: Results showed that the CFU, residual chlorine, COD, and turbidity of direct-drinking water in Shanghai elementary and middle schools ranged from <LOD->300 cfu/mL, <LOD-0.670 mg/L, 0.090-2.710 mg/L, and 0.100-2.050 NTU, respectively. The results of simple linear regression analysis indicated that the CFU of direct-drinking water significantly increased when water temperature was between 25 and 60 °C (β = 19.862, p = 0.030), but it was decreased at 60-100 °C (β = - 16.387, p = 0.046). Additionally, the CFU was higher in elementary schools than middle schools, which was also affected by faucet type and water treatment technology (p = 0.006, 0.012 and 0.042, respectively). The residual chlorine in direct-drinking water significantly increased when there was no toilet within 10 m (β = 0.012, p = 0.045). The COD of direct-drinking water was significantly higher in rural areas and in warm water, compared to urban areas (p = 0.033) and room temperature water (p = 0.000), respectively. The turbidity of direct-drinking water was significantly higher in urban areas and water using UF/MF technology, compared to rural areas (p = 0.030) and RO technology (p = 0.009), respectively. The results of multiple linear regressions analysis drew the same conclusions. CONCLUSIONS: In order to improve the quality of direct-drinking water, the equipment should be as far away from toilet as possible and direct-drinking water should be kept at room temperature or heated at high temperature (over 60 °C). Furthermore, sanitary standards of direct-drinking water quality and relevant laws and regulations should be established and implemented as soon as possible. Our study demonstrates that it is critical to improve direct-drinking water quality and ensure the safety of drinking water in elementary and middle schools in Shanghai.