Scenario-based assessment of fecal pathogen sources affecting bathing water quality: novel treatment options to reduce norovirus and Campylobacter infection risks

Wastewater discharge and runoff waters are significant sources of human and animal fecal microbes in surface waters. Human-derived fecal contamination of water is generally estimated to pose a greater risk to human health than animal fecal contamination, but animals may serve as reservoirs of zoonotic pathogens. In this study, quantitative microbial risk assessment (QMRA) tools were used to evaluate the hygienic impact of sewage effluents and runoff water from municipalities and animal farms on surface and bathing waters. The human-specific microbial source tracking (MST) marker HF183 was used to evaluate the dilution of fecal pathogens originating from the sewage effluent discharge to the downstream watershed. As novel risk management options, the efficiency of UV-LED disinfection and wetland treatment as well as biochar filtration was tested on-site for the contamination sources. According to the dilution pattern of the MST marker HF183, microbes from wastewater were diluted (2.3–3.7 log10) in the receiving waters. The scenario-based QMRA revealed, that the health risks posed by exposure to human-specific norovirus GII and zoonotic Campylobacter jejuni during the bathing events were evaluated. The risk for gastroenteritis was found to be elevated during wastewater contamination events, where especially norovirus GII infection risk increased (1–15 cases per day among 50 bathers) compared with the business as usual (BAU) situation (1 case per day). The noted C. jejuni infection risk was associated with animal farm contamination (1 case per day, versus 0.2–0.6 cases during BAU). Tertiary treatment of wastewater with wetland treatment and UV-LED disinfection effectively reduced the waterborne gastroenteritis risks associated with bathing. Based on the experiences from this study, a QMRA-based approach for health risk evaluations at bathing sites can be useful and is recommended for bathing site risk assessments in the future. In case of low pathogen numbers at the exposure sites, the MST marker HF183 could be used as a pathogen dilution coefficient for the watershed under evaluation. The full-scale implementation of novel tertiary treatment options at wastewater treatment plants (WWTPs) as well as on-site runoff water treatment options should be considered for infection risk management at locations where scenario-based QMRA implies elevated infection risks

Sää- ja ilmastoriskeihin varautumisopas

Ilmastonmuutoksen myötä sään ääri-ilmiöiden (rankkasateet, tulvat, helteet, kuivuus) arvioidaan lisääntyvän ja voimistuvan. Tämän seurauksena esimerkiksi myrskyvahingot, helteestä aiheutuvat terveyshaitat ja kaivovesien kuivuminen saattavat lisääntyä. Tämän oppaan ohjeilla osaat varautua yleisimpiin ilmastonmuutoksen aiheuttamiin sää- ja ilmastoriskeihin. Oppaan on tuottanut HÄMEEN ILMASTOTURVA -hanke (2022-2023), jossa kartoitettiin Hämeen maaseudulle kohdistuvia ilmastoriskejä. Hanke toteutettiin Maaseuturahaston tuella

Sää- ja ilmastoriskeihin varautumisohjeita Hämeen maaseudun asukkaille

Tähän raporttiin on koottu ilmastonmuutoksesta ja muuttuvista sään ääri-ilmiöistä Kanta- ja Päijät-Hämeen maaseudulle aiheutuvia riskejä, ohjeita asukkaille niiden ennaltaehkäisyyn ja varautumiseen sekä katsaus muihin, pidemmän aikavälin ilmastoriskeihin. Raportti on kirjoitettu osana Ilmastoturvallisuuden parantaminen Hämeen maaseudulla -projektia (2022-2023), joka kohdistui ilmastonmuutokseen sopeutumisen suoriin vaikutuksiin. Suorat turvallisuusriskit tässä hankkeessa tarkoittivat ilmastonmuutokseen ja muuttuviin sään ääri-ilmiöihin liittyviä välittömiä riskejä infrastruktuurille ja energiajärjestelmille, logistiselle järjestelmälle, terveydelle ja ruokaturvalle. Hankkeessa käsiteltävät riskit on valittu valtioneuvoston tuottamien raporttien tietojen ja hankkeen asiantuntijatyöpajassa saatujen näkemysten perusteella

Valumavesien hygieenisen laadun parantamiseen liittyvät ratkaisut

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Data_Sheet_1_Scenario-based assessment of fecal pathogen sources affecting bathing water quality: novel treatment options to reduce norovirus and Campylobacter infection risks.docx

Wastewater discharge and runoff waters are significant sources of human and animal fecal microbes in surface waters. Human-derived fecal contamination of water is generally estimated to pose a greater risk to human health than animal fecal contamination, but animals may serve as reservoirs of zoonotic pathogens. In this study, quantitative microbial risk assessment (QMRA) tools were used to evaluate the hygienic impact of sewage effluents and runoff water from municipalities and animal farms on surface and bathing waters. The human-specific microbial source tracking (MST) marker HF183 was used to evaluate the dilution of fecal pathogens originating from the sewage effluent discharge to the downstream watershed. As novel risk management options, the efficiency of UV-LED disinfection and wetland treatment as well as biochar filtration was tested on-site for the contamination sources. According to the dilution pattern of the MST marker HF183, microbes from wastewater were diluted (2.3–3.7 log10) in the receiving waters. The scenario-based QMRA revealed, that the health risks posed by exposure to human-specific norovirus GII and zoonotic Campylobacter jejuni during the bathing events were evaluated. The risk for gastroenteritis was found to be elevated during wastewater contamination events, where especially norovirus GII infection risk increased (1–15 cases per day among 50 bathers) compared with the business as usual (BAU) situation (1 case per day). The noted C. jejuni infection risk was associated with animal farm contamination (1 case per day, versus 0.2–0.6 cases during BAU). Tertiary treatment of wastewater with wetland treatment and UV-LED disinfection effectively reduced the waterborne gastroenteritis risks associated with bathing. Based on the experiences from this study, a QMRA-based approach for health risk evaluations at bathing sites can be useful and is recommended for bathing site risk assessments in the future. In case of low pathogen numbers at the exposure sites, the MST marker HF183 could be used as a pathogen dilution coefficient for the watershed under evaluation. The full-scale implementation of novel tertiary treatment options at wastewater treatment plants (WWTPs) as well as on-site runoff water treatment options should be considered for infection risk management at locations where scenario-based QMRA implies elevated infection risks.</p