Health officials held a press conference Tuesday afternoon to discuss the implications of the new national guidelines for arsenic in drinking water.

Arsenic is naturally occurring within drinking water, and comes from minerals within the earth's surface. It gets into drinking water when ground water dissolves minerals that contain arsenic. Because of the highly mineralized soil that is found in the Yukon, it's not surprising that arsenic is found in the territory's drinking water, according to Environmental Health Services.

The Guidelines for Canadian Drinking Water Quality had previously stated that the acceptable amount of arsenic in drinking water was 0.025 mg/L. With new developments in measurement technology and treatment processes, the new guideline for arsenic in drinking water has been limited to 0.010 mg/L.

Of the 16 communities or subdivisions in the Yukon that have their own water supplies, five of them slightly exceed these new guidelines: Ross River, Teslin, Carcross-Tagish First Nations, the Takhini River Subdivision, and Haines Junction. The range of arsenic levels in those communities is between 0.011 and 0.015 mg/L.

'Keeping in mind that a kilogram is 1000 grams, and this is one one-hundredth of a gram, you can all appreciate that this is a very small amount,' said Bryce Larke, medical officer of health for the Yukon. 'These amounts are on a borderline level. They are very low.

'Anybody who's ever read a mystery novel knows that arsenic is not good; it's used as a favourite in poisoning. But we are all exposed to arsenic at small levels.'

Arsenic comes in many forms, some of which are capable of causing cancer. However, the amount and risk is extremely low.

Environmental Health statistics indicate that in a community of 385,000 people, which is approximately 12.5 times the amount of the Yukon's population, if every person were to drink one and a half litres of water everyday for 70 years at the new guidelines, there would only be one additional case of cancer that could be attributed to that exposure to arsenic.

'The level is low, but it is certainly not zero,' Larke said.

While some carcinogens pose an increased risk for pregnant women and young children, arsenic does not have the same effect. Arsenic also cannot enter the body through the skin when people bathe or shower.

Environmental health officer Pat Brooke said Environmental Health Services is currently addressing the problems within the five affected communities, although it could take a while for it to be completely remedied due to the complexity of the problem.

'There are many factors impacting drinking water which make treatment a complex process, such as PH levels, water demand, and the varying levels of water quality,' Brooke said. 'We're allowing for five years to address these issues, and we're looking towards everyone meeting these new guidelines by July 30, 2011.

'That should give everyone enough time to research options, look at water quality, do testing, have Environmental Health Services follow through on their plans, and secure funding to get the appropriate system in place.

'We're comfortable with that five-year plan because we feel that the health impact is very minimal.'

Handouts have been developed and will be distributed to everyone drawing on the affected water supplies. Another pamphlet has been developed for homeowners who have their own water supplies such as wells.

There are no laboratories in the Yukon which test for arsenic in drinking water, but homeowners can send samples Outside to be tested. They will have to pay $48 for their water to be tested for arsenic, although Brooke said the Yukon Government will pay the shipping costs.

Brooke said they have received data on over 100 wells which have already been tested, and only a very low percentage exceed the new guidelines.

She added that the affected water supplies could be treated through filtration or chemical treatment, depending on the water quality.

'For small systems or private wells, it could be as simple as placing a reverse osmosis unit on the tap,' Brooke said. 'It all depends on a number of factors.'

'Things such as boiling water have no impact on these chemicals,' Larke said. 'The same goes for Brita filters. They have no impact whatsoever on reducing arsenic. So some of the ways that people may think they are purifying their water, won't help them at all.'