Efforts to Improve Water Quality Show Results

Efforts by the province to lower high trihalomethane, or THM, levels in drinking water are improving water quality in many municipalities.

The fourth round of test results, carried out by the Department of the Environment and released today, have been added to the other quarterly results to determine an annual average for 20 municipal water supplies. The Department carried out the tests as part of its mandate to ensure the safety of drinking water.

Overall, the annual average results establish that seven communities fall within the Canadian drinking water quality guidelines of 100 parts per billion. Thirteen still have THM levels that are above.

Dave Wigmore, systems manager at the Department of the Environment, said over the past year, since THM information was first made available, many water suppliers have been controlling THMs and improving overall water treatment.

Mr. Wigmore added he expects to see continued improvements in the coming year. Some of the techniques being used are filters, different disinfection methods and the building or upgrading of water treatment facilities.

Dr. Jeff Scott, Nova Scotia's chief medical officer, said it is reassuring to see the constant progress being made to decrease THM levels.

However, Dr. Scott said that THMs are a byproduct of chlorination. He added while THM should be controlled, chlorination is essential to avoid situations like Walkerton.

"Disinfection is key to preventing illness. If water suppliers are using chlorination to disinfect their water and THMs are created then they need to be managed," Dr. Scott said. "But we must make sure our water is throughly disinfected."

Dr. Scott also said as a Nova Scotian, he personally has never felt uncomfortable drinking the water anywhere in the province.

Mr. Wigmore said the next step is to continue quarterly testing, continue checking and auditing test results, and continue to partner with municipalities to make sure improvements are made in the future. The departments of Health and Environment will continue to monitor the results.

Three other utilities have already lowered their levels through on-going assistance from Department staff. As well, four municipalities with excessive levels are also currently upgrading water treatment systems.

The greatest improvement to date is in Judique. It measured the highest in the first round of testing and is now the lowest. A modified treatment technique that does not create THMs is being credited with the improvement.

Mr. Wigmore said meetings with a working committee of local water utility representatives, municipal members identified by the Union of Nova Scotia Municipalities and government officials will continue and will address both short- and long-term solutions.

Dr. Scott said even though the risk of developing bladder cancer is small, people can reduce THMs by using certified water treatment devices for THM removal or by using bottled water. The devices must be properly maintained to reduce THMs.

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 1993, the Canadian drinking water quality guideline for THMs was made more stringent by lowering it from 350 parts-per-billion to 100 parts-per-billion.

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

NOTE TO EDITORS: Following are the THM survey results for the 20 communities in Nova Scotia.

THM Survey Results, Summer 2000 and Annual Average (All results are in parts per billion; Canadian drinking water guideline = 100 parts per billion)

MUNICIPALITY Sep./99 Jan./00 Mar./00 June/00 Average

Bridgewater 252.0 459.9 338.7 308.9 339.9 Liverpool 390.0 205.9 184.1 179.0 239.8 Hayden 391.0 193.0 82.8 206.0 218.2 Lake Yarmouth 137.3 153.0 184.0 330.0 201.1 Coxheath/ 309.0 135.5 106.4 192.0 185.7 Westmount Glace Bay 84.9 189.6 243.0 216.0 183.4 Windsor 159.0 194.1 143.7 146.5 160.8 New Glasgow 222.0 136.4 100.5 149.0 152.0 Judique 453.0 100.1 < 1 < 1 138.3 Dingwall 238.1 74.9 100.4 135.0 137.1 Mahone Bay 107.8 117.5 137.0 96.4 114.7

Shelburne 299.3 55.9 35.0 41.0 107.8 Cornwallis 263.0 51.8 49.3 59.3 105.8 East Hants 109.0 70.6 42.5 102.1 81.1

REGIONAL
Mulgrave 121.0 62.3 45.8 56.6 71.4 Antigonish 160.0 32.7 41.1 39.4 68.3 Baddeck 103.3 30.6 30.8 82.2 61.7 Stewiacke 101.0 25.8 31.5 87.0 61.3 Arichat 8.2 107.2 55.4 48.0 54.7 Kentville 103.7 39.2 16.9 34.9 48.7