One researcher is trying to get to the bottom of the great ‘invisible’ polluter

22 May 2019

Hayley Hung. Image: Environment and Climate Change Canada

Hayley Hung, a research scientist at Environment and Climate Change Canada, is leading a team to investigate air pollutants in the Arctic.

Environmental research is considered more important than ever as climate change takes its grip on the world. One researcher working in northern Canada and the Arctic to better understand one of its less-obvious problems is Hayley Hung, a research scientist at Environment and Climate Change Canada.

What inspired you to become a researcher?

I grew up in Hong Kong, a crowded and congested city. However, beyond the crazy traffic and super-high rise, the island actually has a lush tropical forest and the ocean is in close proximity. We swam in the ocean and picked out critters from the beaches and rocks.

With the juxtaposition of the city and nature so close to each other, it has always intrigued me how strong nature can be despite all the pressures that an urban city puts on it. At the same time, I worry about how human activities have impacted Mother Nature, which supports all lives.

At the University of Toronto, I studied under Prof Don Mackay, a world-leading scientist in environmental chemistry. It was through Mackay that I learnt about how synthetic chemicals – although invisible to the naked eye – can be carried by air and ocean currents. These can contaminate the environment, bioaccumulate in the food chain, and put wildlife and human health at risk.

This knowledge made me rethink our daily actions and the chemicals that we use all the time without thinking twice (eg pesticides, oil and gas) and how, due to our ignorance, such actions are affecting nature as well as our own being.

Can you tell us about the research you’re currently working on?

I lead the air monitoring programmes for persistent organic pollutants (POPs). Through these programmes, my team conducts research on the movement of toxic contaminants carried by air currents to remote locations in the Arctic and the Great Lakes. The fastest route for contaminants to move around the globe is through the atmosphere.

When these contaminants deposit to the ground and the water, they can enter the food chain and accumulate in wildlife and eventually in people, posing a risk to their health. Being the world’s longest-operating air monitoring programmes for organic contaminants, they provide us with valuable information regarding how contaminant levels have changed over time.

For POPs, such as polychlorinated biphenyls that have been banned for several decades now, the concentrations have been going down in air over time in the Arctic and the Great Lakes, and some of them have now reached very low levels.

This is very good news because it shows that chemical control initiatives have been effective in reducing the levels of these contaminants in the environment. However, for some newer contaminants such as flame retardants and chemicals used as water- and oil-repellent (such as those applied to hamburger wrappers), the air concentrations are not changing and some are even increasing.

In your opinion, why is your research important?

Our study gives us information on where toxic organic contaminants have come from, how much from which region, and what climate conditions influence their movement to the Arctic and the Great Lakes. Continuous measurements over time would give us information on how the behaviour of these contaminants will be affected by climate change.

The time trends derived from our programmes are used for evaluation of domestic and international chemical control initiatives. Canada is a member country of the global agreement of the Stockholm Convention on POPs, which was put in place to control the emission, production and usage of chemicals that were found to be problematic. We hope that when a contaminant is subject to global chemical control, such as banning or restricted use, the air concentrations will go down in Arctic and Great Lake air.

What are some of the biggest challenges you face as a researcher in your field?

One of the biggest challenges is the large amount of chemicals being used and developed for commercial use every day. How chemicals move around in the environment depends on their physical and chemical properties, which are also unknown for many of these chemicals.

The emission rates of these chemicals are uncertain and difficult to estimate. Once they are released into the environment, they may transform or degrade to different chemicals with unknown chemical structures, and there are cases where the degradation products are more toxic than their parent chemicals.

It is impossible to look for all the chemicals that can potentially show up in air at remote locations such as the Arctic and the Great Lakes. The environmental circulation and exposure risk to complex chemical mixtures and cocktail effects is one of the greatest challenges.

Are there any common misconceptions about this area of research?

As contaminants in air are invisible and there are no immediate health effects by breathing in atmospheric contaminants, research in this area is often regarded as unimportant. Although communities in northern Canada understand that the atmosphere is an input pathway for the contaminants in country foods, the question always comes down to: ‘Can we eat the fish?’

How does one translate air concentrations of contaminants to concentrations in wildlife? I think the key to addressing this issue is through outreach and community engagement. Such efforts are fruitful; they help us in building trust and allow us to learn what kind of research is important to Northerners.

What are some of the areas of research you’d like to see tackled in the years ahead?

Climate change’s effects on contaminant transport pathways, and identification of emerging chemical concerns in air through a combination of non-targeted and targeted screening methods are some of the things I’d like to see tackled in the years ahead.

Are you a researcher with an interesting project to share? Let us know by emailing with the subject line ‘Science Uncovered’.