Canadian biologists have developed a device to quickly identify genetic changes caused by oil spills or other chemical exposures in wildlife in the far north, a valuable tool for responding to environmental disasters.
Carleton University and the Environment and Climate Change Canada team spent several years building and perfecting the device called ToxChip.
This is a small plate that allows the laboratory to measure the expression of about thirty genes, in this case in seabirds, which are associated with chemical upheavals caused by pollution in the surrounding environment.
It allows for a gain in efficiency and offers more specificity compared to traditional detection methods because it can be adapted to the species being studied and the type of pollution in the natural environment, the researchers say.
Populations at risk during discharge
With the expected increase in shipping traffic in the Canadian Arctic and increased oil and gas exploration, the risk of spills of oil products is increasing, the researchers note, in a recent study. Already, Arctic freight transport has tripled in the last 25 years, with declining ice allowing for a longer shipping season.
In this context, it is important to be able to monitor and intervene against endangered animals in the event of pollution of the natural environment. Especially since communities in the Arctic live off hunting, fishing or the tourism industry and may themselves be exposed to pollutants through the food chain.
The team led by Jennifer Provencher from Environment Canada selected two species of seabirds, namely gBrunnich’s guillemot and black guillemot, to test its device.
Seabirds are good indicators of pollution of the natural environment because they are quite high 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 this body detoxifies blood from the body, says Yasmeen Zahaby, a master’s student in biology at Carleton University. The compounds then accumulate in the adipose tissue of the bird.
Polycyclic aromatic compounds are the major pollutants found in oil products. They especially cause cancer in birds when ingested. Seabirds that become contaminated through food or that are coated with oil during a spill can no longer move properly and multiply. Entire colonies may thus be threatened, the researchers explain.
Biologists traveled to the Akpait National Wildlife Area and the Qaqulluit Preserve, off the east coast of Baffin Island, Nunavut, to collect liver samples from about 30 individuals of each species to establish a reference for a healthy and therefore unpolluted population. Therefore, when pollution (waste or otherwise) occurs, researchers will have a point of comparison.
Yasmeen Zahaby explains that the liver samples from the birds being examined are quickly analyzed in the laboratory. We first measure the chemical compounds present in the liver tissue and then the expression levels of the genes of interest that respond to the contamination (these may be genes involved in metabolism, in the immune system or in DNA repair, e.g.).
In this way, it can be determined how and to what extent the birds have been affected.
“Traditional tests were developed for experimental animals, such as chickens. However, chickens have different tolerance levels and react differently to chemicals compared to wild species. We could not make valid comparisons, ”says Ms Zahaby. Therefore, we had to develop a way of dealing with wild animals.
“The second benefit is the chemical specificity. Traditional testing can only be performed on one chemical at a time, but most pollutants, such as 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, ”she 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 that on different animal species, the researchers clarify, which opens up the possibilities.
“I am currently working on the development of a Toxchip for the eider, a duck species found throughout Canada,” Ms Zahaby said. This will allow us to study the effects of chemicals not only in the Arctic, but wherever this species is found. »