Baseline Results

WHAT GUIDELINES DO WE COMPARE OUR RESULTS TO?

The Canadian Health Measures Survey (CHMS) represents the Canadian population. It has similar ages, gender, and participant numbers.

The reference level set by the CHMS is 21 µg/L inorganic arsenic in urine. 

HOW MUCH IS THAT? 21 drops of water in a 10,000-gallon swimming pool.

YKHEMP uses the reference levels to compare Yellowknife area populations to other Canadians. A higher result does not mean your health is at risk.

Phase One: Establishing Baseline Levels

Dr. Laurie Chan and his team from the University of Ottawa are pleased to announce that the first phase of the Yellowknife Health Effects Monitoring Program (YKHEMP) is complete, giving local residents a comprehensive baseline picture of the level of arsenic exposure and other metals for the first time. The results of the study demonstrate that, overall, residents of Yellowknife, Ndılǫ, and Dettah are within a similar range of exposure to arsenic to the rest of Canada,” explained Dr. Chan.

Having achieved this primary goal, the YKHEMP team will help ensure the Giant Mine Remediation Project does not negatively affect the health of the communities in the course of its activities.

During their study, Dr. Chan and his team measured arsenic concentrations in urine and toenail samples collected from participants. Lead and cadmium concentrations were also measured in the urine samples. With over 2000 participants, the results obtained by Dr. Chan’s team allow a direct comparison with the Canadian general population results collected in the Canadian Health Measures Survey.

The study also looked to establish a baseline level of exposure using toenail samples, which allow for a longer point-in-time comparison than urine sampling can establish. As there are currently no guidelines for arsenic in toenails, increased support is offered to the individuals who had higher levels of arsenic in their toenail samples, based on the recommendations of the NWT’s Chief Public Health Officer. The Chief Public Health Officer, as well as other health advisors from the Government of the Northwest Territories Department of Health and Social Services and from Health Canada, have been actively involved on the study’s Advisory Committee since it was launched in 2017.

Establishing this baseline was crucial to the accurate monitoring of contaminant exposure in the years to come. Arsenic occurs naturally in the Yellowknife area because of the local geological formations, and this means the YKHEMP study currently cannot distinguish whether recent arsenic exposures come from natural sources, dietary sources, or from the former mines. The study will be repeated every five years to follow the trend of exposure and investigate the potential association with general population health.

The summary results were shared with the public during three community meetings with three different population groups (Yellowknife general population, North Slave Métis Alliance and Yellowknives Dene First Nation) between May 14th and June 8th, 2019.

“The results of the study demonstrate that, overall, residents of Yellowknife, Ndılǫ, and Dettah are within a similar range of exposure to arsenic to the rest of Canada,” explained Dr. Chan. 

The study also looked to establish baseline level of exposure using toenail samples, which allow for a longer point-in-time comparison than urine sampling can establish. As there are currently no guidelines for arsenic in toenails, increased support is offered to the individuals who had higher levels of arsenic in their toenail samples, based on the recommendations of the NWT’s Chief Public Health Officer. The Chief Public Health Officer, as well as other health advisors from the Government of the Northwest Territories’ Department of Health and Social Services and from Health Canada, have been actively involved on the study’s Advisory Committee since it was launched in 2017.

Establishing this baseline was crucial to the accurate monitoring of contaminant exposure in the years to come. Arsenic occurs naturally in the Yellowknife area because of the local geological formations, and this means the YKHEMP study currently cannot distinguish whether recent arsenic exposures come from natural sources, dietary sources, or from the former mines. The study will be repeated every five years to follow the trend of exposure and investigate the potential association with general population health.

Inorganic Arsenic found in Urine compared to the Canadian Average of 5.4 µg/L

urine results-01

Some children from the Yellowknife population and the Yellowknives Dene First Nation have slightly higher average inorganic arsenic compared to adults in the study and other Canadian children of 5.4 µg/L. However, all averages are still well below the 21 µg/L reference level.

For adults and children with higher inorganic arsenic levels, we found that they ate store-bought seafood and rice more often.

Cadmium in Urine: All Populations

cadmium results-01

Cadmium levels well below 0.41 for adults and 0.26 for CHMS children. Higher levels in our study were mostly found in adults, most of whom smoked.

Lead in Urine: All Populations

lead results-01

Higher lead levels were confirmed with a more accurate blood test. Most tests came back low.

The CHMS does not have any reference for Toenail Samples

We compared our study data with old mining towns in Arizona, Australia and the United Kingdom.

toenail results-01
  • 158 people (72 adults, 86 children) out of 1,872 had arsenic levels above the set reference level in toenails.
  • We found that some children may be exposed to higher levels of arsenic. We found 2 possible reasons for this:
    1. Children have smaller bodies and as a result have a higher intake of arsenic per body weight, and/or

    2. Children spend more time outdoors, not wash their hands, and put dirt or dirty hands into their mouths.

At present, we saw no evidence that people’s health is at risk at the arsenic levels we are seeing in the Yellowknife area, including those above the reference level. However, this is a long-term study and we will continue to look at health effects in future testing.

Anyone above the reference level for arsenic, cadmium or lead is asked to:

FOLLOW-UP WITH OUR NURSE PRACTITIONER TO ANSWER ADDITIONAL QUESTIONS ABOUT DIET AND LIFESTYLE, PROVIDE ADDITIONAL BIOLOGICAL SAMPLES AND RECEIVE UPDATED RESULTS.

THE HIGHER RESULT DOES NOT MEAN THAT YOUR HEALTH IS AT RISK, IT JUST MEANS WE WANT TO FOLLOW-UP WITH YOU AS A PRECAUTION.

Follow-up appointments with a Nurse Practitioner can be scheduled by phone at 1.867.445.1574 or by emailing ykhemp@uottawa.ca (currently postponed due to COVID-19 restrictions)

What’s next?

Baseline Study Results for Individual Groups (2019)

Preliminary Summary Results for Individual Groups (2018)