News & Events

Health risks of nitrates in drinking water

19 October 2017

Water pouring from a tap into a glass.Nitrate (NO3) is a compound that is formed when nitrogen combines with oxygen. Sometimes high amounts of nitrate get into drinking water. Typical sources of nitrate include:

  • fertilisers,
  • animal wastes, particularly in areas of intensified farming,
  • unreticulated sewage disposal systems, and
  • industrial and food processing waste.

Nitrate is highly soluble in water, making it readily transported through the soil to groundwater.

Negative health effects of nitrates in drinking water

High levels of nitrate can pose a risk to babies less than six months who are formula fed and the unborn foetus of pregnant women. Adults with specific rare metabolic disorders may also be at risk.

Nitrate is converted into nitrite by bacteria in the gut. This nitrite combines with foetal haemoglobin in the foetus or infant less than 6 months old, preventing oxygen from binding and being distributed around the body. Symptoms include blueness around the mouth, hands and feet – hence the name ‘blue baby’ syndrome. In severe cases it can affect breathing and be life-threatening.

Fully breastfed infants are not affected as nitrites do not enter the breast-milk. Very few cases of ‘blue baby’ syndrome have been reported in New Zealand, though nitrates in groundwater have been rising in the last twenty years.

Nitrate levels in your drinking water

Council water supplies in Canterbury currently have safe nitrate levels.

Many rural drinking water bores in Canterbury are at risk of elevated nitrate levels. Some private bores exceeding the recommended safe level of nitrates. Environment Canterbury (ECan) has produced maps identifying where nitrate levels in drinking water may be a concern – last updated in 2015.

The maps identify green, yellow and red areas:

  • Green areas are where nitrate concentrations in groundwater are always below the Maximum Acceptable Level (MAV) and the water is therefore safe to drink.
  • Red areas are where nitrate concentrations in groundwater are above the MAV most or all of the time. Alternative water sources should be used for drinking in these areas.
  • Yellow areas are where it is not known if a sample collected from a well will have nitrate concentrations exceeding the MAV. Testing is recommended in these areas.

Get your bore water tested for nitrates

The drinking water consumed by pregnant women, or formula fed babies under 6 months coming from a private bore in a medium to high risk area should be tested for nitrates.

Testing is the only way to detect nitrate as it is tasteless, odourless and colourless. There are several laboratories that are able to test for nitrate.

Drinking Water Standards for New Zealand set a Maximum Acceptable Level (MAV) of 50mg/L for nitrate, which is equivalent to 11.3mg/l nitrate-nitrogen. Some laboratories report nitrate levels whereas other report nitrate-nitrogen. Ensure that you are aware which they are reporting if you are getting your water tested.

What do if your drinking water has high nitrate levels

If tests show that nitrate levels are above or close to the MAV then pregnant women and formula-fed infants less than 6 months should use an alternative water source for drinking or making up formula.

If tests reveal that nitrate levels are above half the MAV then the water is safe to drink. However the water should be tested monthly to ensure that it does not increase over the MAV.

Nitrate levels do vary over the year. Often results are highest in spring (following rain and snow melt). High nitrate levels have been found in late summer in areas where there is extensive irrigation.

October is the start of Legionnaires’ season

3 October 2017

Man with mask potting plants in soil.

It’s gardening season so it’s time to reach for the spade, the wheelbarrow, the gloves, and the face mask!

Canterbury has the country’s highest incidence rates of potentially-fatal Legionnaire’s disease, while New Zealand has the highest reported incidence of the disease in the world.

Legionnaire’s disease causes a form of pneumonia. Contact with compost and potting mix is a main contributor as that’s where the Legionella longbeachae bacteria can lurk.

Gardeners are encouraged to wear a mask to prevent inhaling the dust. Even using unwashed hands to remove a mask can be enough to become infected.

“It’s a timely reminder to our community that hand washing immediately after gardening is very important in protecting against Legionnaire’s disease,” says Canterbury Medical Officer of Health Dr Ramon Pink. “Reducing the risk of becoming infected is vital as more of us get out into our gardens with the longer days and warmer weather”.

A recent CDHB-funded study of the disease by University of Otago researchers found that gardeners washing their hands immediately after use protected against the disease, by minimising exposure of the bacteria to the face. The report also recommends long term smokers and those with cardiac or respiratory conditions take particular care of their hygiene during and after gardening.

271 cases have been notified nationwide in the last 12 months – 49 of those in Canterbury. 30 percent of patients hospitalised with the disease require time in the intensive care unit.

Five simple steps to avoid Legionnaire’s disease from potting mix or compost

It is important that gardeners follow these five simple steps to avoid catching Legionnaires’ disease from potting mix or compost:

  1. Open potting mix bags carefully using scissors, rather than ripping them.
  2. Wear a disposable face mask and gloves and open the bag away from your face.
  3. Do your potting in a well-ventilated area outside.
  4. Dampen down the potting mix or compost with a sprinkle of water to stop the bacteria from becoming airborne.
  5. Wash your hands thoroughly after handling potting mix and doing any gardening.

Symptoms of Legionnaire’s disease to look out for

Symptoms of the disease may include:

  • dry coughing
  • high fever
  • chills
  • diarrhoea
  • shortness of breath
  • chest pains
  • headaches
  • excessive sweating
  • nausea
  • vomiting, and
  • abdominal pain.

Anyone who gets these symptoms should see their general practice team immediately, and let them know they have been handling potting mix or compost recently.

Source: Canterbury DHB media release (3rd October 2017).

Boil water notices still in place for many Kaikoura residents

18 August 2017

Last updated: 20th September 2017

People in the Kaikoura and Hurunui Districts are being reminded that boil water notices remain in place at several locations – over nine months on from the November 2016 earthquake.

Canterbury Medical Officer of Health Dr Alistair Humphrey says boil water notices are in place at water supplies in the Kaikoura and Hurunui Districts.

“These warnings remain in place because these supplies are not secure and remain at risk of bacterial contamination. Drinking the water without boiling it first could make you very sick,” says Dr Humphrey.

The boil water notice applies to water used for:

  • drinking,
  • cooking and food preparation,
  • washing dishes,
  • brushing teeth, and
  • making ice.

People living in or visiting the following areas need to boil their water:

  • Kaikoura Suburban – approximately 25 residents.
  • East Coast Rural – approximately 150 residents.

Several other rural Hurunui water supplies remain on a permanent boil water notice:

  • Blythe Rural water – approximately 40 residents.
  • Hurunui No 1 Rural water – approximately 680 residents.
  • Kaiwara Rural water – approximately 130 residents.
  • Lower Waitohi Rural water – approximately 315 residents.
  • Parnassus Rural water – approximately 210 residents.
  • Peaks Rural water – approximately 85 residents.
  • Waiau Rural water – approximately 500 residents.

Dr Humphrey is also reminding people to test their own private water supplies quarterly, as well as after heavy rainfall, and following any significant earthquakes.

Other ways to prevent gastro bugs in the Kaikoura region

Kaikoura residents should remain vigilant in preventing gastro bugs, with the risk from damaged water infrastructure still affecting many in the district.

People are also encouraged wash their hands and keep out of any contaminated waterways.

Dr Humphrey says that everyone should always remain vigilant about hand washing too. “It’s important to wash your hands thoroughly to prevent gastro infections such as Norovirus, which can spread quickly across a community.”

Dr Humphrey also warns people to not swim, surf or consume seafood and shellfish collected in the area where Lyell Creek discharges into the ocean.

“Advice from the Kaikoura District Council on the state of wastewater infrastructure indicates people should stay away from the Lyell Creek area until further notice.”

Source: Canterbury District Health Board media releases (8th February, 11th May and 15th June 2017) and Kaikoura and Hurunui District Council websites.

Sparklers: Helping tamariki live brighter

16 June 2017

Canterbury’s had more than its fair share of challenges over the past six and a half years. The impact has also been felt strongly for many young Cantabrians who have lived through the quakes.

Two primary-school aged boys dressed as pirates with eye-patches and moustaches.The Canterbury DHB’s School-Based Mental Health Team (SBMHT) and the Health Promoting Schools staff from Community and Public Health were often being asked for tools to help schools support the anxiety and mental health issues many students were facing.

So they put their heads together with the All Right? campaign to come up with something that would help schools better support the wellbeing of their students. The result is Sparklers – an online wellbeing toolkit full of activities proven to help young people be calmer and ready to learn.

The 36 activities take between 10 minutes and one hour, and cover topics such as tummy breathing, managing worries and kindness.

Sparklers also includes six parenting guides containing information on how parents can support child wellbeing at home, as well as parenting courses and other support available.

All Right? Manager Sue Turner says Sparklers pulls together wellbeing activities that are simple and easy to implement in the classroom and proven to work.

“The activities help young people discover ways to be calmer, more empathic, and more aware of their emotions. Sparklers helps tamariki build positive mental health and cope with life’s challenges by teaching skills that help them to look after their own wellbeing,” says Sue.

Sparklers has been extensively piloted in Canterbury schools and the feedback has been overwhelmingly positive. Pilot participant and teacher Vicki McKenzie used Sparklers with the 116 tamariki (children) and five kaiako (teachers) in her Pegasus Bay School learning community.

“We loved the activities we tried and will continue to use them next term. I tried the My Amazing Brain activity and the tamariki were really engaged and loved learning about their brain and how they have the power to change it!” says Vicki.

Sue Turner says that Sparklers is relevant to tamariki throughout New Zealand. “We think of Sparklers as a kind of gift to the nation. It’s a really positive thing that’s come out of the greater Christchurch earthquakes, and its benefits will extend far beyond Canterbury,” says Sue.

Find out more about the Sparklers online wellbeing tool.

Sparklers has been made possible thanks to funding from the Canterbury Earthquake Appeal Trust and the Canterbury DHB.

Source: Canterbury DHB Well Now (Winter 2017).

Some emergency kits a recipe for disaster

2 May 2017

Example of a homemade emergency survival kit.It could be the little box that saves your life, which is why authorities are warning Kiwis to be wary of pre-made emergency survival kits after our consumer watchdog found some lacking.

Consumer NZ released a report on 28th April 2017 saying that some pre-made survival kits on the market they tested were more of a “recipe for disaster” than life-savers.

Consumer NZ chief executive Sue Chetwin says while there are a couple of pre-made emergency kits worth considering, you’re generally better off building your own.

“We put together a grab bag with 3 days’ rations and all the key items you’d need to see you through for $150 – considerably less than you would pay for many of the commercial kits,” Ms Chetwin says.

“It’s also likely you could put together your own kit for less than what we paid as most households are likely to have some of the items, such as a spare backpack or water bottles.”

Example of a getaway kit if you need to leave home or work in a hurry.However, taking the first steps to emergency-preparedness is far more important than compiling the perfect getaway kit, Ms Chetwin said. Your emergency planning should cover where you will meet if you can’t get home and a backup plan if you can’t pick up the kids, as well as:

  • The name and contact details of someone who lives out of town that your family knows to contact in case the phones go down;
  • A list of family and friends who may require your assistance;
  • Plans for if you’re stuck at home, including 3 days’ worth of food and water;
  • Plans for how you’ll stay warm at night and cook food if there’s no power; and
  • Getaway kits if you need to leave in a hurry.


Source: Consumer NZ media release (28th April 2017).

Page last updated: 23/02/2016

Copyright © 2017, Community & Public Health, Site by Wired