Water and sediment quality of rain watertanks

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Abstract

In the last decade, there has been a rise in urban rainwater harvesting and its use as a drinking water supply even though a reticulated water system exists. Rainwater is not endorsed for drinking by health authorities due to the variability in quality when compared with the reticulated supply. This variability in rainwater quality is partly due to the ingress of contaminants that accumulate in the sediment layer of the tank. The objective of the current study was to assess the metal composition and determine the presence of specific microorganisms of interest in water and sediment samples from household rainwater tanks in metropolitan Adelaide. The microbial results were negative for Salmonella spp. and Giardia spp., with one rainwater sample being positive for Cryptosporidium spp., although not C. parvum. Metal levels were generally low in the rainwater samples; however, the levels in the sediment samples were high. Copper, lead and zinc exceeded South Australian guideline values for fill waste, with some tanks having sediment with zinc levels exceeding that for industrial waste. This is the first study investigating the microbiological contamination of the sediment layer, and while its findings are limited by the small sample size (n = 19), they also give an indication of the effects of tank characteristics, maintenance and management practices on the metal levels in rainwater systems.
Original languageEnglish
Pages (from-to)83 - 87
Number of pages5
JournalWater
Volume39
Issue number1
Publication statusPublished - 2012

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