Water

I grew up in Havelock North, a place we called “the village”, a special little town nestled into the Te Mata peak foothills with an abundance of trees, green space, and a small river. It’s still a great place to grow up.

Earlier this year more than 5000 people in Havelock North developed gastroenteritis, a result of contaminated water supply. Two died and many ended up in hospital; some are still dealing with the paralysing disorder Guillian Barre syndrome as result. This event represents a spectacular failure of central and local government to provide a basic requirement of any town – safe drinking water.

The one good thing about this event is that it focussed New Zealanders on the deteriorating water quality throughout the country. While it was proven that the contamination came from a ruminant animal such as a cow, it is still not clear if this is from a faulty well or contamination of the aquifer. It is a moot point. The people seriously affected by this outbreak just know they were sick and that those charged with protecting them had failed.

sean-elias-cattle-in-lake
Cattle in Lake Taylor

This outbreak comes at a time when the government is re-setting standards for fresh water in New Zealand. Terms like swimmable and wadeable are being bandied about, but what do these terms actually mean?

If we swim in water that is contaminated by human or animal faeces, we run the risk of getting many illnesses – including vomiting and diarrhoea – from organisms such as campylobacter, cryptosporidium, and giardia. There is also a risk of ear infections and Hepatitis A. Safe drinking water must have less than 1 E Coli bacteria per 100ml or be chlorinated. To be considered swimmable, the E Coli count should be below 540 per ml. A count below this level does not guarantee you will not get sick but the risk is considered low. Of course these levels fluctuate and are worse after heavy rain. More than 540 per ml is considered “wadeable”, whereas above 1000 is considered unsafe for wading or boating. The government is advocating a bottom line of wadeable. Many people feel that swimmable is a better target.

Along with increased E Coli levels, nitrogen levels are rising in our rivers. Nitrogen leaches from cow urine into ground water and then into rivers and aquifers. High nitrogen levels can cause “blue baby syndrome” in bottle fed babies. In some locations in Canterbury nitrogen levels are now so high that the water is unsafe for babies to drink.

nelsonlakesrjnov09-44
Pure Water in Nelson Lakes National Park

What has this to do with nature? The combination of mud, faeces, nitrogen and phosphorus pollution in rivers is directly toxic to fish. These pollutants also cause a decline in insects that fish depend upon for their food source. The macroinvertebrate community index (MCI) measures the presence of various insect species which are variably sensitive to pollution. When the river water is polluted, the more sensitive ones are the first to disappear. The higher the MCI (range 0-200), the healthier the water. Anything over about 120 is considered healthy. The MCI in the Karamu River that flows through Havelock North has been measured as low as 60, one of the lowest levels of MCI ever recorded.

Healthy nature means healthy people. Our livelihood depends on a healthy environment. A healthy environment means healthy nature. As a nation we urgently need to address the slow train wreck of declining water quality. Forest & Bird is doing this by agitating, educating and, where necessary, litigating – in other words we are “giving nature a voice”.

 

Richard Hursthouse

http://www.mfe.govt.nz/sites/default/files/media/Environmental%20reporting/environment-aotearoa.pdf

http://www.radionz.co.nz/national/programmes/checkpoint/audio/201813133/fresh-water-results-worst-ecology-professor-has-seen

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