Darfield water contamination report released
Animal effluent in the water supply has been pinpointed in a Canterbury District Health Board report released yesterday as the cause of the gastroenteritis outbreak in Darfield last year .
The Community and Public Health division report last year said it was the result of animal effluent entering a well which was not adequately treated, and made a number of recommendations to the Selwyn District Council, among them the need for an alternative water source.
Darfield Medical Centre notified the CDHB of 13 cases of gastroenteritis on August 22 and an outbreak investigation was started .
Twenty nine people tested positive for Campylobacter, a bacterial cause of gastroenteritis with 109 people defined as having probable Campylobacteriosis.
Canterbury Medical Officer of Health Dr Ramon Pink, said when heavy rain caused the contamination it was left untreated as it travelled to the tap.
‘‘The best approach to prevent contamination is to have several barriers in place between potential infection and water related illness,’’ Dr Pink said.
‘‘In this case there were no additional barriers in place,’’ he said.
Recommendations to the council to ensure further waterborne outbreaks do not occur included the need for an alternative ground water source for Darfield, and a multi-barrier approach to drinking water supplies involving protection, monitoring and maintenance of the source.
If the Waimakariri River was to be used as a future water source chlorination needed to continue and it needed to be included in a comprehensive risk management plan covering all weather events.
Selwyn District Council asset manager for water services Murray England, said the council accepted the report recommendations and had begun implementing them as a priority.
‘‘A month before the outbreak council was forced to revert back to the river supply because of problems with our deep bore system. These problems have now been fixed and this has allowed us to return to our deep bore. Repeated testing has found water from this source to be free of microorganisms, meaning it is safe to drink,’’ Mr England said.
‘‘We were very concerned by the contamination that occurred in Darfield and will be continuing to upgrade our water supplies to ensure residents have access to safe drinking water.’’
The construction of a second deep bore water source for Darfield is planned to start in April