摘要
Background The Qingcaosha Reservoir is facing issues of algal blooms and eutrophication, and the resulting increase in the level of chlorination disinfection by-products in the water has been a major concern. Objective To evaluate the impact of "Algae Monitoring and Control Program in Qingcaosha Reservoir" (hereinafter referred to as the program) on the control of trihalomethanes (THMs) in conventional finished water. Methods From 2011 to 2019, water samples were collected from the Lujiazui Water Plant once per season, one sample each time, and the concentrations of four THMs (trichloromethane, dichlorobromomethane, monochlorodibromomethane, and tribromomethane) were measured in the samples. Using 2014 when the program was implemented as a cut-off point, the entire study period was divided into two phases: pre-implementation (2011–2013) and post-implementation(2014–2019). Segmented linear regression with interrupted time series analysis was applied to assess the concentrations and trends of THMs in the finished water before and after the program launch. Results The concentration of total THMs in finished water increased by 1.561 µg·L−1 (P=0.010) for each season of time extension before launching the program. The change in the concentration of total THMs in finished water was not statistically significant after the program launch, but the THMs concentration showed a decreasing trend as the slope was −0.626 (P=0.001). From 2017 until the end of 2019, the average concentration of THMs in finished water of Lujiazui Water Plant dropped to 10 μg·L−1 or less. Conclusions The algae and eutrophication control measures in Qingcaosha Reservoir have achieved good results, controlling THMs in finished water at a low level, and the trend of THMs has changed from a yearly increase pattern before the program to a yearly decrease pattern after the program.
摘要
Background The substantial health damage attributed to heat waves, along with their increasing intensity and frequency in the context of global warming, highlights the importance of exploring the health effects of heat waves. Objective To calculate the excess heat stroke cases during heat waves in the summer of 2013—2023 in Shanghai, analyze the association between heat waves and heat stroke, and to further explore the modifying effects of heat wave characteristics on heat stroke. Methods Using a retrospective ecological study design, data on heat stroke cases were collected from the heat stroke case reporting system of the Chinese Center for Disease Control and Prevention, and concurrent meteorological data from Xujiahui Meteorological Station. A heat wave was defined as at least 3 consecutive days with daily maximum temperature meeting or exceeding 35 ℃ in this study, excess heat stroke cases related to heat waves were assessed as the difference between the numbers of heat stroke cases observed on a given day and the corresponding 31 d (15 d before and after that day) moving average, and statistical analyses using generalized linear model based on time series study were performed to assess the impact of heat waves on heat stroke. Results Overall 25 heat waves during the study period were observed, leading to a total of estimated 792.6 extra heat stroke cases. The risk of heat stroke significantly increased during heat waves (RR=2.60, 95%CI: 2.08, 3.26), but no statistically significant differences in heat wave effects were observed among different genders, ages, or regions. In terms of the timing of heat waves, the risk of heat stroke was highest during the first heat wave (RR=3.58, 95%CI: 2.82, 4.55), which was significantly higher than that during the second heat wave (RR=2.19, 95%CI: 1.66, 2.90), and no significant effect was observed during the third or subsequent heat waves. The impact of heat waves on heat stroke persisted for more than 4 d, with the risk higher on the fourth day and beyond (RR=2.95, 95%CI: 2.28, 3.83), significantly higher than on the first day of heat wave (RR=1.74, 95%CI: 1.18, 2.56). Conclusion Heat waves had a substantial effect on heat stroke in Shanghai from 2013 to 2023, and special attention need to be paid to heat waves with early onset and long duration.
摘要
Background Nitrosamines (NAms) are highly carcinogenic and frequently detected in drinking water systems in China, indicating potential human health risk through drinking water. Objective To analyze the distribution of NAms in drinking water in Shanghai and to evaluate relevant human health risk. Methods A total of 94 samples of source water and 120 samples of finished water were collected in February (dry period) and August (wet period) of 2021 from 30 drinking water plants in Shanghai, and eight NAms were quantitatively analyzed by gas chromatography tandem mass spectrometry after solid phase extraction. Cancer risks for different age groups caused by NAms exposure through water were evaluated using Monte Carlo probabilistic method and carcinogens risk assessment model recommended by the United States Environmental Protection Agency. Results The concentrations of total NAms in source and finished water were 12.56-65.86 ng·L−1 and 8.52-57.38 ng·L−1, respectively. The average concentration of total NAms was higher in source water (33.50 ng·L−1) than in finished water (22.07 ng·L−1, P<0.05) during dry season, and lower in source water (16.90 ng·L−1) than in finished water (21.02 ng·L−1, P<0.05) during wet season. The average concentration of total NAms in source water during dry season was twice of that during wet season. The positive rate of N-nitrosodimethylamine (NDMA) was the highest (100%) among the eight NAms. The cancer risk of exposure to NAms in finished water in Shanghai was mainly from the ingestion route, which was mostly caused by NDMA. The cancer risk from exposure to NAms in water for children (median=4.32×10−5) was slightly higher than that for adults (median=3.34×10−5) and adolescents (median=2.27×10−5). The cancer risks of exposure to NAms in water for people of different ages were mainly (80% - 95%) at an acceptable level (1×10−6 - 1×10−4). Conclusion NAms contamination is positive in Shanghai’s drinking water and NDMA is the main contaminant. The removal of NAms in water by current water treatment process is season-dependent. The cancer risk of children exposed to NAms in water was slightly higher than that of adults and adolescents, but all at acceptable levels.
摘要
Background Non-occupational carbon monoxide (CO) poisoning is a public health problem that seriously affect people’s health and lives. Objective To describe the prevalence of non-occupational CO poisoning during 2007—2018 in Shanghai, analyze its epidemiological characteristics and potential influencing factors, and explore effective prevention and control measures. Methods Daily reported non-occupational CO poisoning cases and meteorological factors from 2007 to 2018 were collected in Shanghai, epidemiological characteristics were analyzed by descriptive epidemiology methods, and a distributed lag nonlinear model was used to assess the association between temperature and non-occupational CO poisoning. Results A total of 2264 non-occupational CO poisoning events and 3866 cases from 2007 to 2018 were reported in Shanghai, including 59 death cases. More than half of the poisoning cases were female (56.3%), and young adults accounted for more cases than any other age group (54.8%). The poisoning events mainly occurred in winter (from December to next February); however, cases reported in summer increased in recent years. The peak period of the events was from 20:00 to 24:00. Households (85.2%) and restaurants (8.0%) were the common places of non-occupational CO poisoning events, and the main cause was improper use of gas water heater (36.9%). A nonlinear curve was found between daily average temperature of current day and the occurrence of non-occupational CO poisoning. Temperature was negatively associated with the risk of non-occupational CO poisoning when the temperature was lower than 9.6 ℃, while a positive association was found during 9.7-26.0 ℃. Conclusion Winter is a high season for non-occupational CO poisoning in Shanghai, rising cases reported in summer is also worthy of attention. Supervision should be strengthened to ban sales of unqualified gas water heaters, and health education on CO poisoning prevention and control should be conducted through multiple channels, in order to reduce the incidence of CO poisoning.
摘要
Objective@#To explore the related factors of death from severe heat stroke in Shanghai from 2013 to 2017.@*Methods@#The data of 1 152 patients with severe heat stroke who were divided into survival (n=1 037) and death (n=115) groups including gender, age and heat stroke type (heat cramp, heat exhaustion, heat apoplexy and the mixed type) were collected from meteorological bureau and case report system for high temperature heat stroke in Shanghai from 2013 to 2017. Meanwhile, the meteorological data of the onset date of severe heat stroke cases were collected, including maximum temperature, minimum temperature, daily temperature, relative humidity, air pressure, precipitation and wind speed. The differences of individual and meteorological factors between the two groups were compared, and multivariate logistic regression model was used to analyze the related factors of death from severe heat stroke.@*Results@#Among 1 152 cases, the mean±SD of age was (56.29±18.95) years old, 843 (73.18%)were male, 962 (83.51%) were in the heat wave period; 322 cases (27.95%) were heat cramp, 170 cases (14.76%) were heat exhaustion, 533 cases (46.27%) were heat apoplexy and 114 cases (9.90%) were the mixed type. Daily average temperature ((32.81±1.99) ℃), daily maximum and minimum temperatures ((38.20±2.24) ℃ and (29.22±1.94) ℃) in survival group were lower than those in death group (all P values<0.001), which were (33.76±1.17) ℃, (39.19±1.31) ℃ and (29.72±1.66) ℃. Daily average relative humidity ((60.36±9.75)%) and daily minimum relative humidity ((41.26±9.71)%) in survival group were higher than those in death group(allP values <0.05), which were (54.59±6.89)% and (35.60±7.24)%. The results of logistic regression analysis suggested that compared with the cases with daily average humidity <60% and a mixed type heat stroke, the death OR (95%CI) values of cases with daily average humidity >60%, heat cramp, heat exhaustion and heat apoplexy were 0.31 (0.18,0.54), 0.13 (0.05,0.34), 0.68 (0.58,2.30) and 0.87 (0.48,1.58).@*Conclusion@#The temperature, relative humidity and the type of heat stroke were the main related factors affecting the prognosis of severe heat stroke.