应用定量微生物风险评估海水浴场人体健康风险

Assessment of human health risks from marine bathing beach:based on quantitative microbial risk assessment

【背景】定量微生物风险评估作为定量评估游泳人群暴露于病原微生物后健康风险的方法,在国外已得到广泛应用,但目前国内的应用处于起步阶段且缺乏所需的游泳人群暴露数据。【目的】收集游泳人群暴露数据,并在海水浴场中进行应用,评估粪大肠菌群作为风险评估指标的可行性。【方法】通过对6个典型海水浴场的水质状况、粪大肠菌群浓度与环境因子的相关性进行分析,并发放调查问卷收集国内游泳人群的暴露数据,进而应用定量微生物风险评估方法,得出各个海水浴场的胃肠道疾病患病风险。【结果】6个海水浴场中粪大肠菌群浓度均与水温、气温及总云量具有显著相关性(P<0.01)。位于南方的海水浴场粪便污染情况较北方严重,粪大肠菌群浓度第95百分位数远高于国内“差”类水质标准的阈值。儿童、成年男性、成年女性单次沐浴事件吞下海水的体积分别为35.1 mL(95%置信区间为32.4−37.8,α=0.578,β=0.016),45.0 mL(95%置信区间为31.1−59.3,α=0.532,β=0.012),35.7 mL(95%置信区间为29.7−41.8,α=0.753,β=0.032)。6个海水浴场患胃肠道疾病的风险均远低于美国环保署规定的安全阈值。【结论】粪大肠菌群虽然对粪便污染具有良好的指示作用,但不适用作为评估海水浴场人体健康风险的指标,建议选取肠球菌与人源拟杆菌作为指示微生物。

[Background]Quantitative microbial risk assessment(QMRA),a valuable tool for estimating the burden of disease due to the exposure to pathogenic microorganisms,has been widely used abroad.However,the application in China is in its infancy and there is a lack of data on human exposure in marine bathing beaches.[Objective]To collect exposure data of swimming populations and apply them in marine bathing beaches to assess the feasibility of fecal coliform as a risk assessment indicator.[Methods]The correlation of water quality and fecal coliform concentration in six marine bathing beaches with environmental factors was analyzed,and the exposure data of domestic swimming populations were collected based on questionnaire survey.Then QMRA was employed to evaluate the risk of gastrointestinal diseases from each marine bathing area.[Results]Fecal coliform concentration in the six bathing areas was significantly correlated(P<0.01)with water temperature,air temperature,and total cloud cover.The fecal contamination in the southern bathing areas was more serious than that in the northern bathing areas,and the 95th percentile of fecal coliform concentration was much higher than the threshold of the domestic“poor”water quality standard.The volume of seawater swallowed by children,male adults,and female adults in a single bathing event was 35.1 mL(95%confidence interval=32.4–37.8,α=0.578,β=0.016),45 mL(95%confidence interval=31.1–59.3,α=0.532,β=0.012),and 35.7 mL(95%confidence interval=29.7–41.8,α=0.753,β=0.032),respectively.The risk of gastrointestinal diseases from all six marine bathing sites was well below the safety threshold set by the US Environmental Protection Agency.[Conclusion]It is recommended Enterococcus and human Bacteroides,rather than fecal coliform which can reflects fecal contamination,be used as indicators of human health risk from marine bathing sites.