title: Microbial contamination of groundwater at small community water supplies in Finland.
abstract: The raw water quality and associations between the factors considered as threats to water safety were studied in 20 groundwater supplies in central Finland in 2002-2004. Faecal contaminations indicated by the appearance of Escherichia coli or intestinal enterococci were present in five small community water supplies, all these managed by local water cooperatives. Elevated concentrations of nutrients in raw water were linked with the presence of faecal bacteria. The presence of on-site technical hazards to water safety, such as inadequate well construction and maintenance enabling surface water to enter into the well and the insufficient depth of protective soil layers above the groundwater table, showed the vulnerability of the quality of groundwater used for drinking purposes. To minimize the risk of waterborne illnesses, the vulnerable water supplies need to be identified and appropriate prevention measures such as disinfection should be applied.
authors.affiliation: Department of Environmental Health, Water and Health Unit of National Institute for Health and Welfare, Kuopio, Finland. tarja.pitkanen@thl.fi
authors.forename: Tarja
authors.initials: T
authors.lastname: Pitkänen
authors.forename: Päivi
authors.initials: P
authors.lastname: Karinen
authors.forename: Ilkka T
authors.initials: IT
authors.lastname: Miettinen
authors.forename: Heidi
authors.initials: H
authors.lastname: Lettojärvi
authors.forename: Annika
authors.initials: A
authors.lastname: Heikkilä
authors.forename: Reetta
authors.initials: R
authors.lastname: Maunula
authors.forename: Vesa
authors.initials: V
authors.lastname: Aula
authors.forename: Henry
authors.initials: H
authors.lastname: Kuronen
authors.forename: Asko
authors.initials: A
authors.lastname: Vepsäläinen
authors.forename: Liina-Lotta
authors.initials: LL
authors.lastname: Nousiainen
authors.forename: Sinikka
authors.initials: S
authors.lastname: Pelkonen
authors.forename: Helvi
authors.initials: H
authors.lastname: Heinonen-Tanski
mesh_terms: D004203:Disinfection; D016983:Enterococcus / Q000302:isolation & purification*; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D004926:Escherichia coli / Q000302:isolation & purification*; D005387:Finland; D018709:Statistics, Nonparametric; D014871:Water Microbiology; D018508:Water Purification; D014881:Water Supply / Q000706:statistics & numerical data*