The decay and distribution of bacterial pathogens in water is an important information for the health risk assessment to guide water safety management, and suspended algae might affect bacterial pathogens in water. Th...The decay and distribution of bacterial pathogens in water is an important information for the health risk assessment to guide water safety management, and suspended algae might affect bacterial pathogens in water. This study established microcosms to investigate the effects of algae-related factors on the representative indicators and opportunistic pathogen species in water. We found that suspended algae increased the persistence of targeted species by 1-2 orders of magnitude of concentrations compared to microcosms without algae;and the effect of algae on microbial survival was affected by water nutrient levels(i.e., carbon, nitrogen and phosphorus), as the increased microbial persistence were correlated to the increased algae concentrations with more nutrient supplies. Moreover, decay and distribution profiles of representative species were determined. The three opportunistic pathogen species( Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus aureus) showed lower decay rates(0.82–0.98/day, 0.76–0.98/day, 0.63–0.87/day) largely affected by algae-related factors, while the enteric species( Escherichia coli and Enterococcus faecalis) had higher decay rates(0.94–1.31/day, 0.89–1.21/day) with little association with algae, indicating the propensity for attachment to algae is an important parameter in microbial fate. Together results suggest suspended algae played an evident role in the decay and distribution of bacterial pathogens, providing important implications regarding microbial safety in recreational water.展开更多
The microbial quality of urban recreational water is of great concern to public health.The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify mic...The microbial quality of urban recreational water is of great concern to public health.The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks.To assess the levels of bacterial pathogens and health risks in urban recreational water,we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year.The pathogen diversity revealed by 16 S r RNA gene targeted next-generation sequencing（NGS） showed that 16 of 40 genera and 13 of 76 reference species were present.The most abundant species were Acinetobacter johnsonii,Mycobacterium avium and Aeromonas spp.Quantitative polymerase chain reaction（q PCR） of Escherichia coli（uid A）,Aeromonas（aer A）,M.avium（16S r RNA）,Pseudomonas aeruginosa（oaa） and Salmonella（inv A） showed that the aer A genes were the most abundant,occurring in all samples with concentrations of 10^（4–6） genome copies/100 m L,followed by oaa,inv A and M.avium.In total,34.8% of the samples harbored all genes,indicating the prevalence of these pathogens in this recreational waterbody.Based on the q PCR results,a quantitative microbial risk assessment（QMRA） showed that the annual infection risks of Salmonella,M.avium and P.aeruginosa in five activities were mostly greater than the U.S.EPA risk limit for recreational contacts,and children playing with water may be exposed to the greatest infection risk.Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and q PCR.展开更多
Study on eco-landscape attraction focuses on the congregate effect of production factors, but the spatial alienation of the congregate factors is an academic blind zone. This paper takes urban eco-water recreation spa...Study on eco-landscape attraction focuses on the congregate effect of production factors, but the spatial alienation of the congregate factors is an academic blind zone. This paper takes urban eco-water recreation space as the experiment object, explores the spatial alienation process of eco-landscape attraction, i.e., the homogeneous landscapes' attraction prefers alienation after factor magnetic field's differentiation, and then the attraction spaces of similar landscape areas are apt to alienation, finally leading to another new eco-landscape attraction's spatial structure of "homogeneous landscapes repel each other, heterogeneous landscapes attract" and the construction of eco-recreation alternating buffer model. In addition, this research proposes the testing procedures and evaluation method of that model, ensuring the structural innovation and application universality of the new urban recreation space planning.展开更多
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No.2017ZX07202002).
文摘The decay and distribution of bacterial pathogens in water is an important information for the health risk assessment to guide water safety management, and suspended algae might affect bacterial pathogens in water. This study established microcosms to investigate the effects of algae-related factors on the representative indicators and opportunistic pathogen species in water. We found that suspended algae increased the persistence of targeted species by 1-2 orders of magnitude of concentrations compared to microcosms without algae;and the effect of algae on microbial survival was affected by water nutrient levels(i.e., carbon, nitrogen and phosphorus), as the increased microbial persistence were correlated to the increased algae concentrations with more nutrient supplies. Moreover, decay and distribution profiles of representative species were determined. The three opportunistic pathogen species( Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus aureus) showed lower decay rates(0.82–0.98/day, 0.76–0.98/day, 0.63–0.87/day) largely affected by algae-related factors, while the enteric species( Escherichia coli and Enterococcus faecalis) had higher decay rates(0.94–1.31/day, 0.89–1.21/day) with little association with algae, indicating the propensity for attachment to algae is an important parameter in microbial fate. Together results suggest suspended algae played an evident role in the decay and distribution of bacterial pathogens, providing important implications regarding microbial safety in recreational water.
基金supported by the Key Program of the National Natural Science Foundation of China(No.51138006)the National Key Research on Water Environment Pollution Control in China(No.2012ZX07301-001)
文摘The microbial quality of urban recreational water is of great concern to public health.The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks.To assess the levels of bacterial pathogens and health risks in urban recreational water,we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year.The pathogen diversity revealed by 16 S r RNA gene targeted next-generation sequencing（NGS） showed that 16 of 40 genera and 13 of 76 reference species were present.The most abundant species were Acinetobacter johnsonii,Mycobacterium avium and Aeromonas spp.Quantitative polymerase chain reaction（q PCR） of Escherichia coli（uid A）,Aeromonas（aer A）,M.avium（16S r RNA）,Pseudomonas aeruginosa（oaa） and Salmonella（inv A） showed that the aer A genes were the most abundant,occurring in all samples with concentrations of 10^（4–6） genome copies/100 m L,followed by oaa,inv A and M.avium.In total,34.8% of the samples harbored all genes,indicating the prevalence of these pathogens in this recreational waterbody.Based on the q PCR results,a quantitative microbial risk assessment（QMRA） showed that the annual infection risks of Salmonella,M.avium and P.aeruginosa in five activities were mostly greater than the U.S.EPA risk limit for recreational contacts,and children playing with water may be exposed to the greatest infection risk.Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and q PCR.
基金Sponsored by 2014 Key Program of Jiangsu Provincial Applied Social Science Researches(14SWC-018)Key Program of Youth Foundation of Nanjing Institute of Tourism&Hospitality(2013NLY001)
文摘Study on eco-landscape attraction focuses on the congregate effect of production factors, but the spatial alienation of the congregate factors is an academic blind zone. This paper takes urban eco-water recreation space as the experiment object, explores the spatial alienation process of eco-landscape attraction, i.e., the homogeneous landscapes' attraction prefers alienation after factor magnetic field's differentiation, and then the attraction spaces of similar landscape areas are apt to alienation, finally leading to another new eco-landscape attraction's spatial structure of "homogeneous landscapes repel each other, heterogeneous landscapes attract" and the construction of eco-recreation alternating buffer model. In addition, this research proposes the testing procedures and evaluation method of that model, ensuring the structural innovation and application universality of the new urban recreation space planning.
