Arsenic Concentrations

What you need to know

The Regional Council, based on advice from HB District Health Board, encourages everyone with their own bores to have them tested, to be sure that arsenic levels are within safe limits.

Water sampling for arsenic typically costs less than $100 - refer to the list of sampling agencies below. Long term consumption of water with arsenic concentrations greater than 0.01 mg/L can cause adverse health effects, even increasing the risk of cancer. Boiling water for drinking does nothing to reduce the potential effects of arsenic in water, rather it increases the concentration.

Owners of private bores used for drinking water supply are responsible for maintaining, monitoring and treating their own supply. Water is considered acceptable to drink if it meets limits set for certain materials covered in the Drinking Water Standards for New Zealand – DWSNZ.

Unless specifically testing for levels of arsenic, anyone who has recently conducted a water quality test will not know whether higher than acceptable levels of arsenic are present. Most testing of the groundwater by the Regional Council and Napier City and Hastings District Councils has not found any issue with arsenic levels in groundwater.

The release of arsenic from surrounding materials is local to specific bores. It does not occur consistently throughout aquifer systems. Elevated arsenic levels are naturally occurring in groundwater, due to the presence of specific materials in the aquifer.

The presence of naturally-occurring arsenic in groundwater is not unique to Hawke’s Bay. It also occurs in other areas of New Zealand, such as Waikato, Manawatu, Marlborough, Canterbury, and many other places worldwide.

Exposure, Symptoms and Signs

If your drinking water has been shown to have high levels of arsenic, stop drinking the water. Contact the Health Protection Team at Hawke’s Bay District Health Board for further advice - 06 878 8109. For example, depending on levels detected, you may still be able to use the water for washing, showering and bathing - there is only limited absorption through the skin.  Similarly water may still be suitable for some garden use.

Symptoms and signs of arsenic exposure include:

• Changes to skin - thickening of palms or soles of feet and/or speckling/ pigmentation
• Gastrointestinal symptoms - anorexia, weight loss, nausea, alternating diarrhoea and constipation, and abdominal colic
• Feeling weak, giddy or headaches.

People wanting health advice or who have specific health concerns should talk to their GP. For information on what test results might mean in terms of risk to health, call the on-call Health Protection Office on 06 878 8109.

Water Sampling

Information on water sampling is available from laboratories who can perform analysis. These include:

• Hill Laboratories – Hamilton 0508 44 555 22
• Analytical Research Laboratories – Napier +6468359222
• Water Testing Hawke’s Bay – Hastings +6468706449.