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Legislative Council - Fifty-Third Parliament, Second Session (53-2)
2016-12-06 Daily Xml
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Water Quality

The Hon. M.C. PARNELL (14:57): I seek leave to make a brief explanation before asking the Minister for Water and the River Murray another question about water quality and, in particular, the presence of trihalomethanes in Adelaide's drinking water.

Leave granted.

The Hon. M.C. PARNELL: The issue of trihalomethanes in drinking water has arisen most recently during debate over the expansion of Adelaide Hills townships and extra residential development in the Mount Lofty Ranges water protection area. Trihalomethanes are compounds that can occur in chlorinated water supplies as a by-product of organic materials present in the water reacting with the chlorine.

One of the submissions to the Adelaide Hills Council's public consultation on increasing development in the Adelaide Hills refers to this problem and suggests that, as the amount of housing increases, the quality of water will decrease and the amount of chlorine required to treat Adelaide's water supply will increase. The submission goes on to say that they believe that Adelaide has one of the highest levels of THM (trihalomethanes) of any city in the developed world.

A quick look at the SA Water Drinking Water Quality Report 2014-15 shows that, of all the different pollutants in our water that we measure, the only one that failed across the metropolitan area was trihalomethanes. I also note that the health level that it failed to meet is actually three times the US level. We already have, it seems, on the government's own data a problem with this pollutant in our drinking water.

My question to the minister is: what steps is he taking to ensure that the quality and safety of drinking water in Adelaide will not be compromised by increased development in the Mount Lofty Ranges water protection area?

The Hon. I.K. HUNTER (Minister for Sustainability, Environment and Conservation, Minister for Water and the River Murray, Minister for Climate Change) (14:59): I am not exactly sure what the honourable member is referring to in terms of increased development. Is he suggesting perhaps (and I do this by way of a hypothetical because I know that he can't respond, and undertake to check this out for him) that further housing development in the Adelaide Hills area—for example, Mount Barker, Murray Bridge or other areas—will put increased pressure on the water supply and therefore increase interactions between organic matter that is in the water system currently with chlorine, resulting in chloramines, which is the chlorine smell people have coming out of their taps; or is he saying that in fact increased development means more run-off into the water supply reservoirs?

The Hon. M.C. Parnell interjecting:

The Hon. I.K. HUNTER: He is nodding and saying that's exactly what he means. Indeed, we have a big problem in the Adelaide Hills in particular, but in South Australia I suppose, in terms of our water storages because they are very close indeed to developed areas and agricultural and farming areas. If you fly over Victoria or New South Wales, for example, and glance out of the plane as you do, you will see that most of those large water storages—which hold water at great depth and in great quantity and provide those cities with water security for a period of years compared to our storages, which provide storage security for a period of months—are in fact often surrounded by vast areas of either commercial forest or natural native vegetation.

That is not the situation with us. We have to work with what we've got—low hills, essentially with country towns or hills-based towns and, cheek by jowl, you will find agricultural production. So, you get all these effects that you get from town run-off, road run-off and agricultural production in terms of, for example, manure and urine run-off, and chemicals of course used for agricultural production. These are all issues that challenge our water supply system, not the least of those being town run-off as well, but these are areas in which SA Water has great expertise in managing.

We have dosing stations at most of our storages that supply water to actually do what we need to do: to decrease the amounts of chemicals that are coming into the system, usually by treating them with other chemicals and floating them out of the system or some other method perhaps using membranes, and additionally to treat it with levels of chlorine which will make it safe, and particularly with agricultural practices, you have to worry about cryptosporidium, which is one of the obvious ones. These are things that SA Water has great expertise in. They have great expertise in this in terms of the metropolitan area and also our storages in the Hills, and I have no reason to suspect that they won't be able to manage this into the future.

The PRESIDENT: The Hon. Mr Parnell, supplementary.

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