Preliminary Study Of Human Health Risk Assessment For Typical Bacteria On Marine Bathing Beach

Withtheimprovementof people’s living standard, more and more people choose to do recreational activities on marine bathing beaches during hot climate. Industrial and agricultural wastewater, urban garbage to coastal waters increasing, microbiological quality of the marine recreational water was extremely impaired, the quality of marine recreational water meets a great challenge.Most common recreational waterillnesscaused by fecal pollution is gastrointestinal disease.Bathers can also get acute febrile respiratory disease. Over the past 30 years, many countries such as America, England, Canada, Australia, Japan and some world wide organization such as WHO and EU, have been working on human health risk assessment on marine recreational water. But there was rarely study reports in China. Using bacteria assess human health on bathing beaches hasn’t seen before.Our country has a long coastline, and there are many coastal cities,it is quite necessary to estimate human public health risk during recreational activities on marine bathing beaches.Quantitative microbial risk assessment(QMRA) method has been widely used to analyze health risk for recreational activities at bathing beaches in western countries. However, the application of QMRA in assessing health risk of bacterial index in China is still scarce.This research monitored Dalian Xinghai bathingbeachand Fujiazhuangbathingbeachduring the summer of 2014 and 2015. Xinghai bathing beach and Fujiazhuang bathing beach are two of four major bathing beaches in Dalian, and summer is Dalian’s bathing season. We collected a total of 138 marine water samples, and monitored enterococcus(ENT), fecalcoliform(FC), staphylococcus aureus, human-specific Bacteroidetes and 3 species of Vibrio(Vibrio parahaemolyticus, Vibrio choleraeand Vibrio vulnificus).The researchpreliminary evaluated human healthriskof swimming in marine bathing beaches in Dalian and 23 typical bathing beaches nation wide by models for fecal coliform, enterococcus, and staphylococcus aureus utilizing quantitative microbial risk assessment method.The results were as following:1. From August to September, 2014, the concentrationof ENT at Dalian Xinghai bathing beach was 7.00 ×101 CFU/L~5.00×104 CFU/L, and was 3.30×101CFU/L~5.54×104CFU/L at Fujiazhuang bathing beach. From 31 th, July, 2015 to 16 th Aug, 2015, the concentration of ENT at Fujiazhuang bathing beach varied from 4.30×102 CFU/L~1.17×104 CFU/L. According to Recreational Water Quality Criteriasetby US EPA, the qualifiedrateswere 23.33%(Fujiazhuang) and 20.37%(Xinghai) in 2014. The qualified rete at Fujiazhuang bathing beach during 2015 was 0%.The concentrationof ENT 12 hoursafterrainfallwassignificant higherthanthatatsunnydays(P<0.001). Besides rainfall, bather number, tide condition also affected bacteria concentration.2. Our research evaluated human health risk by using enterococcus at bathing beaches in Dalian, China. Results showed that the average risk probabilities for men, women and children were 24.09‰, 17.46‰ and 29.76‰ respectively during tour season in Dalian, 2014. Recreational risk of men and children has exceeded the acceptable threshold set by EPA(i.e. 19‰).In 2015, the risk probabilities of GI associated with ENT for men, women and children in Fujiazhuang bathing beach were 1.78‰~43.31‰, 1.19‰~30.03‰ and 2.37‰~55.55‰. The risk probabilities of GI associated with FC were 0.02‰~8.34‰, 0.01‰~5.59‰ and 0.03‰~11.08‰.In 2015, the infect probabilities associated with S.aureusfor men, women and children in Fujiazhuang bathing beach were 0.05‰~5.46‰, 0.04‰~3.64‰ and 0.07‰~7.27‰.Data obtained in this study indicated that rainfall,high bather density and tidal condition were 3 major contributing factors that could increase health risk. According to the results, using ENT to evaluate human health risk at bathing beaches seemed much safer than FC.3. Utilizing QMRA method, we evaluated human health risk at 23 typical marine bathing beaches nation wide from 2003 to 2014. Results showed that at most bathing beaches, bathers’ health risk associated with FC were below 6‰, and there was no such difference between north and south, which tested and verified that QMRA for FC may get low health risk result.4. This study monitored 3 vibrio species in 2014 using PCR method. The detection rate of Vibrio cholerae was7.14%.The detection rate oftotal Vibrio parahaemolyticus(tlh) was 84.52% and pathogenic Vibrio parahaemolyticus(trh) was 34.52%. The detection rate of Vibrio vulnificuswas 16.67%. This study also monitored Human-specific Bacteroidetesin 2015 using real-time q PCR method.Vibrio is veryimportant marine pathogen, and many species can cause human diseases. It is quite necessary to establish a suitable modelfor estimating vibrio-relatedhumanhealth risk in future studies. Human-specific Bacteroidetes had strong correlation with FC, ENT and S.aureus. Both vibrio and Human-specific Bacteroidetes haveprospectsin the study of marine recreational water health risk.This researchput bothindicator bacteriaandpathogenicbacteriaintousetoevaluate water quality of marine bathing beaches. Results implied that rainfall, high bather density and tide could make water quality worse and increase public health risk. This research screened out human health risk assessment index—enterococcus. The study tested and verified the feasibilityofhuman-specific Bacteroidetes as indicatorbacteriain China’s marine bathing beaches. This studyprovided research foundation for heath risk assessment and prediction at marine bathing beaches, and offered instructive advices on reducing gastrointestinal infections and enhancing beach management in the future.