Australian study finds no difference between filtered and unfiltered r
Updated
Drinking waster is obtained from many sources in the Pacific. In a recent survey done in mainly micronesian countries by the Southwest States Regional Water Drinking Program, 60 per cent of people said they got their drinking water from bottled or rain water, but only 55 percent questioned felt their drinking water was safe to drink. Now, a new study by researchers at Melbourne's Monash University and Water Quality Research Australia has looked at whether filtering rain water can make a difference.
Presenter: Geraldine Coutts
Speaker: Associate Professor Karin Leder, Monash University in Melbourne, Australia
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LEDER: I was interested in your opening saying that our study found that it was safe to drink. It's not quite the interpretation of the study actually. The reason we did the study is we do realise that many people in Australia and in the other parts of the world do use rainwater as their main source of drinking water and do not have an alternate water supply. But in areas of Australia where there is also a tap water supply, our health authorities have been reluctant to endorse the use of rainwater for many household purposes, including drinking water, because of a lack of scientific evidence about its safety and because there is significant data that shows that the microbial quality, in otherwords the amount of bugs in rainwater is quite variable and usually much higher than a tap water supply.
COUTTS: Well more than one in ten according to the study of Australian households currently drink rainwater.
LEDER: Yeah, that's true and clearly we are not aware of major health problems amongst the people who are using rainwater for drinking. But without doing systematic unbiased studies to actually compare people who are drinking rainwater versus tap water. It's impossible to say whether there is any contribution of drinking rainwater to health. And in our study, and the reason why I corrected you from the beginning, in our study we compared people who were drinking filtered versus unfiltered rainwater and we didn't find any health difference amongst people who were drinking either the filtered or unfiltered water. It suggests that for the people who enrolled in our study, they were either maintaining their tanks well enough that there wasn't significant contamination or perhaps they were immune to any bugs in the rainwater or perhaps there really is no problems with drinking untreated rainwater. But we can't completely conclude that it is safe compared to a tape water supply when that is available, because that was beyond what our study looked at.
COUTTS: Did did you look at rural versus urban supplies of water, drinking water?
LEDER: We did our study amongst 300 households in metropolitan Adelaide, in South Australia. None of the households are in a particularly industrialised part of the country, but they were also relatively urbanised, not completely rural. We were focusing on potential health risks from microbes, from bugs in the water, than on the potential for chemical risks. And what we did in the study was we provided each of the 300 households that agreed to participate in the study and all of these households were already drinking rainwater as their main water supply. We provided them either with a real or a dummy or sham filter to pass their rainwater through, their rainwater that they were going to be using for drinking or cooking purposes and we did this over a 12 month period, they needed to pass the water through this filter. Neither they nor us, the researchers, knew which households had been given a real filter that actually could remove any bugs that were in the water versus the dummy or sham filter and we asked the householders to record their health on a health diary, particularly focusing on gastroenteritis and so on, diarrhoea and nausea and vomiting over the 12 month period and we found no difference in symptom rates between the two groups.
COUTTS: Just very briefly, because we are out of time. Did the drought situation or after heavy rains make any difference to the quality of water?
LEDER: Actually we did look at water quality over a period of time in a subset of the households and it did seem there was variability within tanks even in the single household and there did seem to be more bugs after a rainfall event, yes.
