In an ongoing effort to address a technological problem, the National Research Council of Canada (NRC) has been working in partnership with the Department of National Defence (DND) for the past 20 years to determine the effect of munitions on the environment. NRC has been conducting ecotoxicological testing to find out how contaminants are impacting earthworms, microbes and plants in DND practice sites.
Through this research, DND is hoping to learn which chemicals are harming the environment, and what kind of alterations it can apply to its munitions to make them more ecologically friendly.
Geoffrey Sunahara, leader of the Applied Ecotoxicology Group at NRC, is responsible for conducting this research. He has been with the team throughout the 20 years and has witnessed the evolution of the goals and scientific processes that are such a crucial part of his team’s research.
“Twenty years ago, ecotoxicology was a very young science,” said Sunahara. “Environmental criteria were mainly chemically-based. And the problem is that, as the chemistry got better and better and better, the limits of detection got lower and lower. They were not, at that time, able to relate a chemical concentration with an effect.”
As a result, NRC has since moved on to biological methods of testing the soil. The team uses microbes, earthworms and plants as biological signalling devices in dose-response relationship testing processes. Essentially, the team observes the effects of contaminants on the ecosystem at varying exposure levels to determine which chemicals have an adverse effect and what contamination levels are safe.
Sunahara stressed that while NRC has not been preoccupied with developing new technologies as of late, they are more than ever in the business of seeking knowledge. To gain that knowledge, researchers use several scientific testing processes. One such process is the core sample technique, which they use to determine whether any particular sampling of soil is contaminated with chemicals that might affect the ecosystem.
This is how it works: researchers remove a large cube of soil from a contaminated site, place a velcro bag into the empty space, then place the cube back in the hole after introducing earthworms to the soil. The velcro bag has small perforations in it which allow rainwater to get in, but discourage earthworms from getting out. Using this method, the researchers can leave the earthworms in the cube for a month or so, and then at the end of that period, they can remove the cube, bring it back to the lab, and study the earthworms to see how they’re reacting to the chemicals in the soil.
“You can put these cubes in areas which you think are toxic and in areas where you don’t think are toxic,” Sunahara explained, “and you try to make that relationship between the effects on the organisms…versus the concentration of the contaminant in that cube.”
Sunahara stressed that testing for lethal levels of chemicals is not the only thing on the agenda; he and his team are also trying to determine the effect of contaminants on other functions, such as on the reproductive cycle of earthworms. Low earthworm populations can have a detrimental effect on the ecosystem, as the worms are needed to move microbes around in the soil – and if the contaminants are affecting earthworms in adverse, unseen ways, then it stands to reason that other parts of the ecosystem are being affected as well.
In addition to this, they are trying to understand how contaminants can show no ill effects on microbes, for instance, but nevertheless show a very drastic negative effect on earthworms. This process is called bioaccumulation: even if microbes thrive on the chemicals in some contaminants, the earthworms must eat the microbes, and can therefore be affected by the contaminants absorbed by those microbes.
“Once [the munitions] started to degrade, it became a very good nitrogen source for microbes,” said Sunahara, citing a study his team conducted on a chemical called CL-20. “In other words, the microbes thrived on it. It was like a very expensive fertilizer. The microbes liked it, the plants liked it because the microbes liked it. But to the earthworms, it was really, really not good.”
Based on the research NRC has done, DND is currently working on developing green insensitive munitions.
Amy Allen is a staff writer with Vanguard’s sister magazine, Canadian Government Executive.
