Application of Quantitative Microbiological Risk Assessment in Beach Hygiene Evaluation:a Case Study of Three Beaches in Hainan
In this study,Escherichia coli and Enterococcus were detected in the intertidal zone and supratidal zone of three different beaches in Hainan Province by selecting culture medium,and analyzed by Kruskal-Wallish test method and Spearman related non parametric test method.Among them,40 sand samples were collected from beaches A and B in the north of Hainan,and 16 samples were collected from beach in the East.And then the infection rate of diseases caused by microorganisms in beach sands was quantitatively evaluated by the framework method of quantitative microbiological risk assessment(QMRA)and Monte Carlo simulation(MCS).The concentration of Escherichia coli in the intertidal zone is higher than that in the supratidal zone,and the former is more than 2.875 times that of the latter;Except for the concentration difference between the intertidal zone and the supratidal zone in the eastern beach,the other two beaches showed that the concentration of Enterococcus in the intertidal zone was higher than that in the supratidal zone(P<0.05),and the former was more than 3.0 times that of the latter.There was a positive correlation between the levels of Escherichia coli and Enterococcus in beach sand(rs=0.586,P<0.01).Through the simulation of the parameters of pathogenic Escherichia coli(EPEC),it is concluded that the health risk caused by Escherichia coli in sand is far less than the acceptable threshold of 0.019 of the United States EPA,while the simulation with the parameters of Escherichia coli O157 : H7 shows that the infection rate caused by skin contact of adults who bury part of their bodies in sand is as high as 0.57.Quantitative microbial risk assessment based on Monte Carlo simulation can be used for the health risk assessment of beaches.However,the final assessment results are different due to the differences in the exposure mode of the population and the indicator of microbial species,which should be used according to the actual situation.The microbial pollution in the intertidal zone in the sand is more serious than that in the supraptidal zone,which may cause health risks to high-risk groups through skin exposure.It is necessary to strengthen the assessment of the health risk of beaches including sand and establish relevant standards for supervision.
quantitative microbiological risk assessmentescherichia colienterococcusbeachMonte Carlo simulation
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