Transcript

ELEANOR HALL: A crop of wilting lettuce in the Victorian town of Werribee is raising questions about the use of recycled effluent in Australia, at a time when it's being proposed for drinking water across the country.

Vegetable growers in the area started using recycled effluent on their crops in January last year.

Since then the result has included stunted, discoloured, or non-existent plants.

So far testing has failed to identify the cause of the problem and the situation has been referred to Victoria's Chief Health Officer.

Alison Caldwell reports.

ALISON CALDWELL: Werribee in Melbourne's south-west provides up to 70 per cent of Australia's lettuces.

Since January last year, vegetable growers in Werribee have been using recycled effluent on their crops to address water shortages caused by Victoria's drought.

Since September though, growers have begun to notice problems with their lettuce... unusually slow crop development, leaf discolouration and in some cases no growth whatsoever.

So far tests have failed to identify a cause, but management at the local water authority admits the recycled effluent could be the source of the problem.

Clinton Rodda is the General Manager of Water Supply with Southern Rural Water.

CLINTON RODDA: The concern relates to some problems that we had with a limited number of customers who had issues with lettuces planted after the 15th of September.

That seems there was a three or four week period where the lettuce just simply didn't take off, didn't grow anywhere near as well as they would have normally, and for that period of time, most of those crops haven't proceeded through to their full size to being harvested.

So, there's been a period of time when customers haven't been able to grow their lettuces in the way they'd like. It's about 12 customers in the irrigation district.

ALISON CALDWELL: What sort of standard of treatment does the water receive that is used by these vegetable growers?

CLINTON RODDA: Melbourne Water treat the water to Class A standards as defined by the Department of Health Services, and all the deliveries during that period have certainly been to that Class A standard.

ALISON CALDWELL: It's a bit of a concern isn't it, given that authorities are hoping that one day in the not-too-distant future, people might actually be confident about actually drinking recycled water, if something like this is going on with vegetables.

CLINTON RODDA: I think we need to make a distinction between the use of it for irrigation purposes and the use of it for drinking water purposes.

ALISON CALDWELL: Problems have also been reported in some of Werribee's cauliflower and broccoli crops.

Victoria's Chief Health Officer Dr Robert Hall has been notified. He's reportedly confident there's no immediate danger to people eating produce.

Southern Rural Water's Clinton Rodda believes the problem is an isolated one.

CLINTON RODDA: The product had been growing well on recycled water up to that period of time, and certainly subsequent crops that have been harvested at the moment have been growing very well.

I mean, the problem it being isolated to about two per cent of the overall district, so it's certainly not universal across recycled water use.

ALISON CALDWELL: What about the concern that some growers have that they're just not receiving anywhere near enough water, even recycled water?

CLINTON RODDA: I think this is an extremely legitimate concern. In Werribee South, we've got a 10 per cent allocation and it's simply because we've had no rainfall over the last, well certainly the last six months.

Really, the recycled water scheme has been the main source of water for the district for this season, and without recycled water, there would be very limited crops growing in the district at the moment.

ELEANOR HALL: Clinton Rodda is the General Manager of Water Supply with Southern Rural Water, and he was speaking to Alison Caldwell.