Did you know that mercury is 1 of the top 10 chemicals of major public health concern, according to the World Health Organization?

Mercury is poisonous not only to humans, but to animals as well.

It can harm the brain, heart, kidneys, lungs and the immune system in excessive quantities.

Photo by: S. Nelson

There have been famous case studies where mercury has polluted water bodies – both nationally in Canada (e.g. Grassy Narrows) and internationally (e.g. Minamata, Japan). Mercury pollution is a global problem.

Sarah Nelson, a MSc student in Environmental and Life Sciences at Trent University, is studying lake chemistry – with a particular focus on mercury.

Sarah working on a project for the Norwegian Institute for Water Research (Photo by: C. Gundersen)

Sarah’s goal is to better understand how different variables, both external and internal, can influence lake chemistry.

Studying mercury pollution is more than just studying how it enters the environment.

It also includes how different chemical variables can influence how long mercury stays, as well as how it moves, within ecosystems.

Although mercury does occur naturally in lake environments, human activities, like industrial spills or coal burning, can cause unnatural increases in the amount of mercury present.  Mercury can also be transported in the air so even the most remote water bodies can have higher levels of unwanted mercury.

Sarah’s research consisted on taking water samples from a series of small remote high elevation lakes in Ireland. 

Photo by: K. Wilkins

She chose these water bodies specifically, because:

  • Ireland sits on the Western periphery of Europe, mostly receiving air masses from over the Atlantic Ocean.
  • The lakes are far away from human-caused pollution or significant influence.
  • They are isolated from any significant sources of mercury pollution – except for small amounts by long-range (transboundary) air pollution.
  • The lakes are NOT influenced by water coming from other water sources with different water chemistry (i.e. no rivers leading into the lakes).

69 Lakes were sampled during the 2 sampling periods – in the spring and summer of 2017 and 2018. The water samples were analyzed for chemical variables, such as pH, alkalinity, conductivity, dissolved organic carbon, and total mercury.

Photo by: H. Cathcart

Sarah’s research is still underway, but she has found:

  1. Mercury concentration in the study lakes is relatively low, as expected, but higher in lakes with high organic matter in the water. This is because mercury binds itself to organic material.
  2. Previous mercury data for these lakes in 2008 suggests that these lakes have higher mercury concentrations now than compared to 10 years ago, despite a decrease in atmospheric mercury pollution.
  3. Chemical interactions in the environment are important when studying mercury concentrations

Political action globally, like the Minamata Convention, has resulted in mercury pollution control by many countries. This could be a reason that atmospheric measurements of mercury on the west coast of Ireland have been decreasing.

Photo by: S. Nelson

However, just because pollution has gone down, this doesn’t necessarily mean the pollutant concentrations in a water body will decrease immediately – mercury will have long lasting effects.

We know that water is a vital resource for life. Protecting natural water resources and understanding what controls toxins in water is a shared global issue.

Other toxic trace metals like lead and cadmium each have their own relationship in water chemistry. It is important to increase our understanding of highly complex water chemical relationships – like the one that mercury plays.

Dramatic changes to our water bodies are happening at more rapid paces. With industrial mining, agriculture, and urban development taking place – we need to pay close attention to keeping them as healthy as possible.

Thank you to Sarah for submitting your research!

Here is what she has to say about her research experience:

I’ve had a wonderful experience with research at Trent University. I first got involved with this project during my BSc and it’s been an excellent learning experience. Trent also has many fantastic connections with other environmental research institutions that have provided me additional opportunities in my field. This past summer I participated in two aquatic research projects run by the Norwegian Institute for Water Research. Additionally, Trent is one of the founding members of the International Institute for Environmental Studies, and participating in their events has allowed me the opportunity to connect with fellow students and learn from professors from universities around the world. I’m very thankful for all the incredible global opportunities that have been available to me during my time at Trent.