De invloed van weersomstandigheden op demicrobiologische kwaliteit van hemelwater toegepast voor toiletspoeling en schoonmaken

摘要

A 2006 study of the microbiological quality of rainwater collected inreservoirs demonstrated that this water was fecally contaminated at allinstances and sometimes contained pathogenic micro-organisms such asCampylobacter, Legionella, Cryptosporidium or Giardia. The amount ofrainfall and rainfall intensity influenced the level of faecalcontamination of the water.The study reported here - a follow up to a pilot study on themicrobiological quality of collected rainwater carried out in 2005 -dealt specifically with the effect of environmental conditions on themicrobiological quality of collected rainwater. Samples were taken fromthree reservoirs at various environmental conditions to study the effectof drought, heavy and normal rainfall (whether or not after a period ofdrought) and temperature. The presence of Campylobacter, Salmonella,Vibrio, Legionella, Cryptosporidium, Giardia and enteroviruses wasdetermined.The number of faecal indicator bacteria in the reservoirs increased withhigh rainfall intensity, especially after a period of drought, andpathogenic micro-organisms such as Campylobacter were detected. Considering the high numbers of Campylobacter found in the reservoirs dueto the runoff of bird faeces from roofs, it is conceivable that therequirement of one infection in 10,000 persons per year, as outlined inthe Dutch Drinking Water Act, will not be met.