Nova Scotia Health says it will pause testing water for chemicals in the province's central zone beginning Monday due to a worldwide shortage of an unnamed chemical component used in the testing.

The health authority said it will reassess the situation in three to four weeks.

According to the province, more than 40 per cent of Nova Scotia households get their drinking water from wells. It encourages regular testing.

The testing provided by the health authority's environmental laboratory services is for municipal, registered and private water supply owners. Testing for bacteria will still be offered.

Linda Campbell, a Saint Mary's University professor who formerly served as the Canada Research Chair in Aquatic Ecosystem Health at Queen's University, said the testing is especially important in Nova Scotia because arsenic occurs naturally in the province's geology.

"Groundwater often becomes elevated in arsenic," she said in an email. "It is a health issue because arsenic is carcinogenic."

She said the use of lead pipes and lead connections is another reason why testing is critical.

Campbell wasn't surprised the reason for the temporary shutdown was the shortage of a chemical. She said her research laboratory has been struggling to obtain the components and chemicals it needs at affordable prices.

"This is a common experience for all analytical laboratories," she said.

Nova Scotia Health provided a list of alternative facilities for water testing, but noted those facilities may be having similar difficulties.