Päivi Kärkkäinen

National Institute for Health and Welfare, Finland, Helsinki, Province of Southern Finland, Finland

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Publications (4)7.42 Total impact

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    ABSTRACT: Microbial particles can readily be released into the air from different types of man-made sources such as waste operations. Microbiological emissions from different biological sources and their dispersion may be an issue of concern for area planning and for nearby residents. This study was designed to determine the concentrations and diversity of microbiological emissions from four different man-made source environments: waste center with composting windrows, sewage treatment plant, farming environment, and cattle manure spreading. Samples of airborne particles were collected onto polyvinyl chloride filters at three distances along the prevailing downwind direction, from each source environment during a period of approximately 1 week. These samples were analyzed for 13 species or assay groups of fungi, bacterial genus Streptomyces, and Gram-positive and -negative bacteria using quantitative polymerase chain reaction (PCR). Samples for determining the concentrations of viable fungi and bacteria were collected from all environments using a six-stage impactor. The results show that there were variations in the microbial diversity between the source environments. Specifically, composting was a major source for the fungal genera Aspergillus and Penicillium, particularly for Aspergillus fumigatus, and for the bacterial genus Streptomyces. Although the microbial concentrations in the sewage treatment plant area were significantly higher than those at 50 or 200 m distance from the plant area, in the farming environment or cattle manure spreading area, no significant difference was observed between different distances from the source. In summary, elevated concentrations of microbes that differ from background can only be detected within a few hundred meters from the source. This finding, reported earlier for culturable bacteria and fungi, could thus be confirmed using molecular methods that cover both culturable and nonculturable microbial material.
    Journal of the Air & Waste Management Association (1995) 12/2011; 61(12):1382-92. · 1.20 Impact Factor
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    ABSTRACT: In this study, we developed two novel qPCR-assays for the detection of bacteria in house dust; one that determines the total bacterial amount and another that detects Gram-positive and Gram-negative bacteria separately. The methods were tested in silico and in vitro with microbial strains and vacuum cleaner dust samples, and validated in relation to culture and chemical marker analysis. We also compared the results of these three types of methods (qPCR, culture and chemical marker analysis) in 211 house dust samples from farming and non-farming environments. Microbial concentrations determined by the new qPCR assays (median 7.2 x 10(5) cell equivalents mg(-1)) were about two orders of magnitude higher than concentrations obtained by culture (median 6.7 x 10(3) cfu mg(-1)). The median concentration of muramic acid was 25.67 ng mg(-1) and that of 3-hydroxy fatty acids, expressed as LPS(10-16) was 26.14 pg mg(-1). Correlations between qPCR and chemical markers were moderate, while correlations between culture and qPCR and chemical markers were low to moderate. All the methods used in this study showed that the microbial concentrations are statistically significantly higher (p < 0.001, Mann-Whitney) in farming than non-farming environments.As a conclusion, all tested methods can be used for determining the bacterial load in dust samples, but none of the methods was superior to the others. The results obtained with these methods represent different aspects of bacterial exposure and therefore the results are not expected to be identical with each other.
    Journal of Environmental Monitoring 03/2010; 12(3):759-68. · 2.09 Impact Factor
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    ABSTRACT: Microbes are present everywhere in outdoor air. However, the general characterization of outdoor air mycobiota and bacterial flora is incomplete. In this study, seasonal variations in outdoor air microbial concentrations and differences between a landfill, urban and rural sites were compared. Samples were collected monthly for a period of one year. Airborne dust samples were collected onto polyvinyl chloride filters. Filter samples were analyzed for ergosterol, and 14 species or assay groups of fungi and for the bacterial genus Streptomyces by using quantitative PCR. Viable bacteria and fungi were collected with a cascade impactor twice each month from the three sampling sites. The concentrations in the different sampling sites varied depending on the species. The concentrations of Penicillium and Aspergillus species were significantly higher in the waste center compared with the other sites, while the concentration of Cladosporium spp. was highest in the rural area. The highest concentrations of Streptomyces and Cladosporium species were observed in warmer weather periods. Similar observations were made for ergosterol. Group and species seasonal variation was less distinct for Penicillium and Aspergillus. According to the present results, both season and environment are determinants of microbial communities in outdoor air.
    CLEAN - Soil Air Water 07/2008; 36(7):556 - 563. · 2.05 Impact Factor
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    ABSTRACT: Prolonged moisture on building materials can lead to microbial growth on them. Microbes can emit spores, metabolites and structural parts into the indoor air and thus, cause adverse health effects of people living and working in these buildings. So far, culture methods have been used for assessment of microbial contamination of building materials. In this work, we used quantitative PCR (qPCR) for the detection of selected fungal and bacterial groups in 184 building materials of different types and compared the results with culture-based analysis. Nine either commonly found species, genera or groups of fungi, or those considered as moisture damage indicators, and one bacterial genus, Streptomyces, were determined using qPCR. Fungi and mesophilic actinomycetes were also cultivated using standard media and conditions of the routine analysis. The bacterial genus Streptomyces and the fungal group Penicillium/Aspergillus/Paecilomyces were the most prevalent microbial groups in all building material types, followed by Stachybotrys chartarum and Trichoderma viride/atroviride/koningii. The highest prevalences, concentrations and species diversity was observed on wooden materials. In general, the results of the two methods did not correlate well, since concentrations of fungi and streptomycetes were higher and their occurrence more prevalent when determined by qPCR compared to culture-based results. However, with increasing concentrations, the correlation generally increased. The qPCR assay did not detect Aspergillus versicolor and Acremonium strictum as often as culture.
    Journal of Environmental Monitoring 06/2008; 10(5):655-63. · 2.09 Impact Factor

Publication Stats

39 Citations
7.42 Total Impact Points

Institutions

  • 2010–2011
    • National Institute for Health and Welfare, Finland
      • Department of Environmental Health
      Helsinki, Province of Southern Finland, Finland
  • 2008
    • National Public Health Institute
      Helsinki, Southern Finland Province, Finland
    • University of Kuopio
      Kuopio, Eastern Finland Province, Finland