SASKATOON — Floods are becoming increasingly common and intensifying across the globe.
Just recently, the world watched as many people were injured and dozens died after a torrential flood swept through a Texas town early in July.
While the immediate impact of these dangerous events is top of mind, University of Saskatchewan (USask) researcher Dr. Markus Brinkmann (PhD) is raising awareness about the environmental and health concerns that persist after flood waters recede.
“There are many things that occur during a flood event. You have those direct impacts of flooding like loss of life and property damage, but there is a lot occurring beyond that, which you can’t really see,” said Brinkmann. “You have wastewater treatment plants overflow which can release pathogens and microbes, but you also have chemical contaminants that are contained in river sediments that suddenly are disturbed and redistributed across the environment.”
The remobilization of chemicals is a topic of interest in this year’s United Nations Environment Programme (UNEP) Frontiers Report, The Weight of Time- Facing a new age of challenges for people and ecosystems. The biennial report delves into topics of emerging environmental concern, bringing attention to global environmental challenges.
Brinkmann, an ecotoxicologist and director of USask’s Toxicology Centre, said the contaminants found at the bottom riverbeds in layers known as sediments, are often chemicals that we stopped using decades ago due to toxicological concerns because of their links to illness, cancer and birth defects. But when disturbed by floods, these chemicals can find their way into fields and even into our food system again.
“We are looking at what we call persistent organic pollutants, ones we’ve used in the past that were intentionally produced or are a byproduct of industrial activity. They are persistent because they stay in the environment for a long time and don’t degrade,” said Brinkmann.
Current flood management strategies emphasize the need for areas known as floodplains, where flood waters can be contained — minimizing damage to cities and infrastructure. Brinkmann said that in some instances floodplains include grazing areas for livestock like cattle, meaning that remobilized chemicals can be deposited in these fields during a flooding event.
“If you get a flood wave rushing through, you get deposition of harmful chemicals. Afterwards, cows will eat the grass, and these chemicals can make their way into our milk and sometimes meat as well. It’s these not-so-obvious interactions that one needs to be concerned about,” said Brinkmann. “The idea is that if you open up the floodplain, you’ll be fine from a flood control perspective, but if you look at contamination issues it’s counterproductive and you’re causing more land contamination.”
The research has brought some interesting solutions to the table and illustrates the need for national and international level collaboration. Brinkmann said since removing chemical pollutants once they are in the environment is difficult, if not impossible, solutions for mitigating chemical contamination from flooding have to come from a strategic level.
“We see that pieces of legislation need to be working together and that the flood protection and chemical management frameworks and guidelines need to take into account the whole picture,” said Brinkmann.
This chapter on chemical remobilization was Brinkmann’s first contribution to the UNEP Frontiers Report, an experience Brinkmann describes as very positive.
“These reports are really meant to start new thinking and get everyone to understand the concerns that are not necessarily top of mind. It was really nice to work with my team of co-authors and UNEP and it was a great experience.”
