加利福尼亚中部流行娱乐游泳场所的微生物安全。
Microbiological safety of popular recreation swimming sites in Central California.
机构信息
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, 4207 Vet Med 3B, Davis, CA, 95616, USA.
Western Institute for Food Safety and Security, University of California, Davis, Davis, CA, 95616, USA.
出版信息
Environ Monit Assess. 2019 Jun 22;191(7):456. doi: 10.1007/s10661-019-7601-2.
The objective of the study was to assess the microbiological safety of popular recreational swimming sites in Central California. Water samples were collected from eleven monitoring sites across the lower reaches of two watersheds for two consecutive swimming seasons (2012-2013), and levels of indicator and pathogenic microorganisms were determined. Data on ambient weather and water chemistry were collected for analyzing their associations with microorganisms in water. All water samples were positive for indicator E. coli with mean concentrations per site ranging from 3.07 to 216.11 MPN/100 ml in 2012 and 13.4 to 226.97 MPN/100 ml in 2013. Mean E. coli concentrations in 27% and 36% samplings sites exceeded the EPA 2012 Recreational Water Quality Criteria recommended mean concentration of ≤ 126 CFU/100 ml of E. coli, in 2012 and 2013, respectively. Cryptosporidium spp. oocysts were detected in all water samples from all sampling sites, with an overall prevalence of 50% and mean concentrations of 0.08 oocysts/l in 2012 and 0.19 oocysts/l in 2013. Giardia spp. cysts were detected at eight sites, with an overall prevalence of 28.8% and mean concentration of 0.2 cysts/l in both years. The majority of the detected Cryptosporidium spp. oocysts and Giardia spp. cysts appeared damaged under microscopy. E. coli O157:H7 was detected in 9% of water samples, with positive samples limited to three sites. Salmonella spp. were detected in all but one site across the two years, with mean concentrations of 0.94 MPN/l in 2012 and 1.85 MPN/l in 2013. Cryptosporidium spp. oocyst concentrations were negatively associated with 30-day mean wind speed and cumulative precipitation and dissolved oxygen in water. Giardia spp. cyst concentrations were positively associated with turbidity and pH of water and negatively associated with E. coli concentrations and 24-h mean air temperature. Salmonella spp. concentrations were positively associated with 30-day mean air temperature. The occurrence of E. coli O157:H7 was positively associated with previous 30-day cumulative precipitation.
本研究旨在评估加利福尼亚州中部受欢迎的休闲游泳场所的微生物安全性。在连续两个游泳季节（2012-2013 年），从两个流域下游的 11 个监测点采集水样，并测定指示菌和病原菌微生物的水平。收集有关环境天气和水化学的数据，以分析它们与水中微生物的关系。所有水样均呈大肠杆菌指示菌阳性，2012 年每个监测点的平均浓度范围为 3.07 至 216.11 MPN/100ml，2013 年为 13.4 至 226.97 MPN/100ml。2012 年和 2013 年，分别有 27%和 36%的采样点的大肠杆菌浓度超过 EPA 2012 年休闲水质量标准推荐的大肠杆菌平均浓度≤126 CFU/100ml。所有水样均检测到隐孢子虫属卵囊，总流行率为 50%，2012 年和 2013 年的平均浓度分别为 0.08 个卵囊/L 和 0.19 个卵囊/L。2012 年和 2013 年，在 8 个采样点均检测到贾第虫属包囊，总流行率分别为 28.8%和 2 个卵囊/L。在显微镜下，大多数检测到的隐孢子虫属卵囊和贾第虫属包囊均呈受损状态。9%的水样中检测到大肠杆菌 O157：H7，阳性样本仅限于 3 个采样点。沙门氏菌在这两年的所有采样点均有检出，但有一个采样点除外，2012 年和 2013 年的平均浓度分别为 0.94 MPN/L 和 1.85 MPN/L。隐孢子虫属卵囊浓度与 30 天平均风速、累积降水量和水中溶解氧呈负相关。贾第虫属包囊浓度与水的浊度和 pH 值呈正相关，与大肠杆菌浓度和 24 小时平均空气温度呈负相关。沙门氏菌浓度与 30 天平均空气温度呈正相关。大肠杆菌 O157：H7 的发生与前 30 天的累积降水量呈正相关。
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