Crawfish can accumulate lithium, an environmental contaminant that is expected to increase as battery use grows, and that could affect the people who eat them. Credit: Javian Ervin
Key points:
- Researchers examined a common Southern crustacean to determine if lithium is on the verge of becoming a significant environmental contaminant.
- The team found crawfish take up lithium in their GI tract, gills, hepatopancreas and abdominal muscle in the tail.
- The lithium can then be transferred to predators of crawfish, including humans.
The increase in technology and electronics over the past decade-plus has been paralleled by an increase in lithium-ion batteries to power these devices. But when these batteries are not disposed of correctly, lithium can accumulate in the environment, with potential implications for public health.
Researchers at Mississippi College recently turned to a common Southern crustacean to help determine if lithium is on the verge of becoming a significant environmental contaminant.
As fully aquatic organisms that spend their lives within a relatively small area, crawfish (Procambarus clarkii) reflect local lithium contamination, making them a suited model. The lithium they contain could be passed through the food chain to predators, including humans, either directly or indirectly through crawfish-eating fish that people consume.
For their research, presented at the at the spring meeting of the American Chemical Society, researchers added ionic lithium to food for five crawfish, while giving another five lithium-free food. They then examined the amount of lithium present in four organs after one week. On average, the team detected the most lithium in the gastrointestinal (GI) tract, followed by the gills, the hepatopancreas and, finally, the abdominal muscle in the tail.
The researchers think the GI tract likely contained the highest level because the lithium-spiked food remains there during digestion. Meanwhile, the gills and the hepatopancreas both pick it up while removing it from the body. Humans predominantly eat crawfish tail, which appears to take up lithium, but not as readily as the other body parts studied.
Study author Andrew Doubert also found that 27.5% of the lithium fed to crawfish passed from the animals’ GI tracts into other tissues. Animals further up the food chain can accumulate higher levels of toxic substances if they eat contaminated prey, so lithium will likely become more concentrated in the predators of crawfish. The researchers expect the high rate of absorption Doubert saw to exacerbate this accumulation in both humans and other animals that eat crawfish.
Doubert also found that water temperature affects lithium uptake for crawfish. Crawfish were placed in tanks kept at temperatures from 50 to 90◦ F, with a consistent concentration of ionic lithium added to the water. After five days, researchers found that lithium uptake by the abdominal muscle and the animals’ exoskeleton increased in the warmest tank. These results suggest that the animals may contain the most lithium during the warm months.
“A lot of people think the use of lithium-ion batteries is a good thing right now, but it is important to explore the effects that may be coming down the road,” said Doubert.