North

Arsenic update: N.W.T health officials share info about arsenic levels in 3 more lakes

The N.W.T.’s chief public health officer has issued an updated public health advisory on arsenic levels in lakes around Yellowknife.

Updated health advisory includes Niven Lake, Fiddlers Lake and Range Lake

This map shows the concentration of arsenic in lakes around Yellowknife. (N.W.T. Department of Health and Social Services )

The N.W.T.'s chief public health officer has issued an updated public health advisory on arsenic levels in lakes around Yellowknife.

The advisory includes information about a number of additional small lakes — Niven Lake, Range Lake and Fiddler's Lake — as well as information about consuming things like mushrooms.

A map provided by the Health Department indicates the level of arsenic concentration in lakes around the city by using coloured dots.

The map provided with the advisory marks Niven Lake with a yellow dot, meaning it has a concentration of 10 to 51.9 parts per billion of dissolved arsenic. Fiddler's Lake and Range Lake are also marked with a yellow dot.

Health Canada's guidelines dictate that water is safe for drinking if it has a concentration of less than 10 parts per billion of dissolved arsenic.

However, officials warn people they shouldn't be swimming in or harvesting berries and edible plants around Niven Lake, which is a former sewage lagoon.

Officials said current information indicates occasionally eating berries or wild plants won't cause harm, but they still advise people to avoid doing so within city limits, because of its industrial history.

Mushrooms picked within 10 to 25 kilometres of Giant Mine pose a low health risk, the advisory states. However, mushrooms shouldn't be eaten within 10 kilometres of Giant Mine, it says.

Officials said mushrooms in the tricholomataceae family — including tricholoma, clitocybe and white matsutake mushrooms — are more likely to accumulate higher arsenic levels and those within 25 kilometres of Giant Mine shouldn't be eaten.

It is still safe to swim in Long Lake and to drink tap water in Yellowknife, according to the health advisory. It is also safe to swim along the shores of N'dilo and Latham Island.