Province Releases Second Set of THM Results

The Department of the Environment released the second set of test results today that chart trihalomethane, or THM, levels in municipal water supplies. The department carried out the tests as part of its mandate to ensure the safety of drinking water.

Water supplies in 20 municipal areas were tested in January. Test areas were selected based on previous results that were above the Canadian drinking water guideline. Of the 20 tested, nine communities are below and 11 have THM levels that are above the guideline.

The province's chief medical officer, Dr. Jeff Scott, said the results were encouraging, but he recognized residents in areas with elevated THM levels may still be concerned.

"The risk in communities where there are high levels of THM is very small," said Dr. Scott. "Still, whenever there is a risk, no matter how small, we should be working to reduce it."

He underlined these are results for the second test and that four tests are needed to get an accurate reading.

Health Canada advises that a person would have to be exposed to high THM levels for at least 25 years or more to increase the risk of bladder cancer. The average male has about a one per cent chance of developing bladder cancer. With prolonged exposure to high levels of THM, the risk would increase to about 1.3 per cent. In women, the risk is less.

In the meantime, Dr. Scott said people can easily reduce THMs from drinking water by using certified water treatment devices for THM removal or by using bottled water. The devices must be properly maintained to reduce THMs.

At the briefing, Department of the Environment systems manager Dave Wigmore announced the formation of a working committee comprising government officials and municipal members identified by the Union of Nova Scotia Municipalities. The committee will address long-term solutions.

As well, Mr. Wigmore said the department is already offering operational advice to municipalities in an effort to lower readings. Three utilities have already lowered their levels through on-going assistance from department staff. Four of the municipalities with excessive levels are also currently upgrading water treatment systems.

Mr. Wigmore added high THMs are a nationwide problem occurring in hundreds of municipalities across Canada.

THMs are created when surface water containing organics is chlorinated for drinking water.

In 1993, the Canadian drinking water quality guideline for THMs was reduced from 350 parts per billion to 100 parts per billion. The guidelines say water systems do not have to comply with the guideline immediately but over time compliance should be achieved when the systems are expanded or upgraded.

NOTE TO EDITORS: Below are THM survey results.

THM Survey Results, Feb. 8, 2000 (All results in parts per billion; Canadian drinking water guideline = 100 parts per billion)

Municipality September 1999 January 2000

Judique 453 100.1

Hayden Lake 391 193

Liverpool 390 205.9

Coxheath 309 135.5

Shelburne 299.3 55.9

Cornwallis 263 51.8

Bridgewater 252 459.9

Dingwall 238.1 74.9

New Glasgow 222 136.4

Antigonish 160 32.7

Windsor 159 194.1

Yarmouth 137.3 153

Mulgrave 121 62.3

Elmsdale 109 70.6

Mahone Bay 107.8 117.5

Kentville 103.7 39.2

Baddeck 103.3 30.6

Stewiacke 101 25.8

Glace Bay 84.9 189.6

Arichat 8.2 107.2