Canadian biologists have developed a device to rapidly identify genetic changes induced by oil spills or other chemical exposures in wildlife in the Far North, a valuable tool in responding to environmental disasters.
The team from Carleton University and Environment and Climate Change Canada spent several years building and perfecting the device called the ToxChip.
It is a small plate that allows the laboratory to measure the expression of thirty genes, in this case of seabirds, which are associated with chemical disorders caused by environmental pollution.
It allows gains in efficiency and offers more specificity compared to traditional detection methods, because it can be adapted to the species under study and the type of contaminant in the natural environment, say the researchers.
Populations at risk during spills
With increased shipping traffic expected in the Canadian Arctic and increased exploration for oil and gas, the risks of petroleum product spills are increasing, the researchers note, in a recent study. Cargo shipping in the Arctic has already tripled in the last 25 years, with receding ice allowing for a longer shipping season.
In this context, it is important to be able to monitor and intervene with animals in danger of extinction in the event of contamination of the natural environment. Especially since Arctic communities live from hunting, fishing or the tourism industry and can be exposed to pollutants through the food chain.
The team led by Jennifer Provencher of Environment Canada chose two species of seabirds, the gramBrunnich’s guillemot and black guillemot, to test his device.
Seabirds are good indicators of pollution of the natural environment because they occupy a fairly high place in the food chain and accumulate chemical compounds in their bodies. These compounds are particularly visible in the liver in the days after exposure, as the liver detoxifies the body’s blood, says Yasmeen Zahaby, a biology master’s student at Carleton University. The compounds then accumulate in the fatty tissues of the bird.
Polycyclic aromatic compounds are the main contaminants found in petroleum products. In particular, they cause cancer in birds when ingested. Seabirds that become contaminated through food or covered in oil during a spill can no longer move properly or reproduce. Entire colonies can thus be threatened, the researchers explain.
Seabirds of Nunavut
The biologists traveled to Akpait National Wildlife Area and Qaqulluit Preserve, off the east coast of Baffin Island, Nunavut, to collect liver samples from about 30 individuals of each species, in order to establish a baseline for a healthy population and, therefore, uncontaminated. When contamination occurs (spill or not), investigators will have a point of comparison.
Yasmeen Zahaby explains that the liver samples from the birds being studied are quickly analyzed in the laboratory. Firstly, we measured the chemical compounds present in liver tissues and then the expression levels of the genes of interest that react to contamination (these may be genes involved in metabolism, the immune system or liver repair). DNA, for example). example).
In this way it can be determined how and to what extent the birds have been affected.
“Traditional tests were developed for laboratory animals, such as chickens. However, chickens have different tolerance levels and react differently to chemicals compared to wild species. We couldn’t make valid comparisons,” says Ms. Zahaby. That’s why we had to develop a way to deal with wild animals.
“The other advantage is chemical specificity. Traditional tests can only be done on one chemical at a time, but most contaminants, like petroleum, are mixtures of hundreds of different chemicals. So this tool allows us to see the effect of pollutants as they are in the real world,” he continues.
“This tool is also cheaper to use, gives results in less time, and the process requires far fewer animals. »
The ToxChip can be adapted to detect the effects of a forest fire, plastic pollution or pesticides, and this on different animal species, the researchers point out, which opens up a field of possibilities.
“I am currently working on developing a Toxchip for the common eider, a species of duck found throughout Canada,” says Ms Zahaby. This will allow us to examine the effect of chemicals not only in the Arctic, but wherever this species is found. »
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