After floods, oil slicks, human and animal waste

Oil slicks, human and animal waste, dead animals and garbage. All of this and more have been seen floating in the water by volunteers working to rescue British Columbia homes and communities flooded after the recent catastrophic storm.

New information on water content is coming out, with the Abbotsford News reporting Friday that asbestos fibers are likely in the floodwaters in the Fraser Valley. Toxic wastes like that will affect the habitat of aquatic and plant life, pollution experts say.

There is the issue of raw sewage, as in Merritt, where the failure of the city’s sewage treatment plant caused thousands to evacuate, which John Richardson, a professor in the department of forest and conservation sciences at the University of British Columbia, said may be less of a problem than other pollutants for wildlife. However, its failure means that the drinking water supply of the entire community is contaminated.

Freshwater systems can break down organic materials, but non-organic pollution can be especially damaging. Richardson is most concerned about the fuel and manure storage tanks in the Abbotsford farmland area. The floodwaters have likely washed them away, he said. “That will include fertilizers, gasoline and other petroleum products. It will probably include a lot of pesticides because a lot of these farms still use a good amount of pesticides, fungicides or herbicides and things like that. “

As a consequence, there will probably be quite high concentrations of those kinds of things, Richardson added, who said they will be dangerous to fish and the thousands of organisms they feed on.

Although the effects will not be known until a proper evaluation is done, keep your fingers crossed that high volumes of water will dilute toxins.

Turbidity of the water, the cloudiness caused by sediment, is also a concern for drinking water and ecosystems alike, he said. Sediments can settle on salmon eggs, enter their gills, and alter their habitat.

What people are reading

Although all flood events are unique, some aspects of the British Columbia disaster can be compared to others in Canada, said Tim Gray, executive director of Environmental Defense.

“Whenever these things happen, you get things like these big animal farming facilities … you end up with all the manure from those huge ponds going to the streams, to the … lakes here,” he said.

“For example, the same [with] the big floods that have been happening in Manitoba, those sewage ponds that go to the Red River. “

To 2018 study Conducted by academics, including McGill’s Elena Bennett, on flooding around the world, said the effects of flooding on freshwater aquatic ecosystems can be difficult to assess and often go unaddressed.

The study looked at the effects that smaller floods (with a 10-year recurrence rate) and extreme floods (a 100-year occurrence rate) had on ecosystems. Although severe flooding is expected to become more intense with climate change, Environment Canada called the British Columbia event a one-in-100-year event.

“Extreme floods caused losses in almost all the ecosystem services considered in this study. However, small floods had neutral or positive effects on half of the ecosystem services we consider, ”the report reads, noting that water regulation and recreation opportunities may increase after smaller floods.

“For example, small floods caused increases in primary production, water regulation, and recreation and tourism. Decision making that preserves small floods while reducing the impacts of extreme floods can increase the provision of ecosystem services and minimize losses ”.

As BC continues to assess flood damage, Gray says the best way to preserve extreme weather habitats is prevention. That includes restoring forest cover and other flood management practices, he said.

“… You really have to think about redoing all the flood mapping and being very aware of what you’re building in places that are within that 100 year floodplain because the floodplain is probably a one in five floodplain. years now, “he said.

Facilities like chemical plants have no place in a flood zone, he noted. “It is necessary to take them to a place where there are no violations of those facilities.”