Unraveling the Mystery of Forever Chemicals: A Journey through the Food Web
The Hidden Dangers of Isomers: Unequal Distribution Revealed
In the complex world of chemistry, not all molecules are created equal, and this inequality extends to the distribution of isomers across our food web. Advanced separation techniques, like cyclic ion mobility spectrometry, are shedding light on this intriguing phenomenon.
Imagine two sheets of paper, one flat and the other crumpled. Despite being made of the same material and weighing the same, the crumpled sheet will hit the ground first. This simple analogy illustrates the concept of shape differences influencing movement, which is key to understanding isomer separation.
The Power of Cyclic Ion Mobility Spectrometry
This advanced analytical technique separates isomers based on their unique shapes. By passing these molecules through a tube filled with gas, such as nitrogen, their movement time, or drift time, is measured. Branched isomers, with their compact, spherical shapes, move faster than elongated linear isomers, revealing a fascinating distinction.
Unraveling PFAS in Fish
Researchers at the RENEW Institute, with support from the UB Office of the Senior Vice President for Research, Innovation and Economic Development, analyzed PFAS in supermarket fish samples. They studied both benthic fish, like blue catfish and cod, and pelagic fish, such as rainbow trout and salmon.
The results, published in the American Chemical Society's Journal of Agriculture and Food Chemistry, showed a higher presence of branched PFOS isomers in benthic fish. Additionally, these fish contained two unique branched PFOS isomers not found in pelagic samples. This led to a significantly higher total PFOS concentration in benthic fish, which also had higher proportions of longer-chain PFAS.
The Impact on Consumers
Mindula Wijayahena, a PhD student and first author of the study, highlights the potential impact on consumers: "These results suggest that consumers who frequently eat bottom-dwelling species may have a higher exposure to PFAS."
A Surprising Twist in Bird Eggs
In a separate study published in the Journal of the American Society for Mass Spectrometry, researchers analyzed PFOS isomers in wastewater and bird eggs. While wastewater samples showed a majority of branched PFOS, the egg yolks of double-crested cormorants, an aquatic bird, contained nearly 90% linear PFOS.
Jenise Paddayuman, a PhD student and first author of this study, raises an intriguing question: "Although we know linear isomers tend to accumulate more in tissue, the reason for this heavy skew towards linear in the eggs warrants further investigation."
The Future of PFAS Regulation
With the ability to distinguish PFAS isomers, researchers are now considering the differences in their toxicological effects. Diana Aga suggests that it may be time to examine these differences, which could lead to the need for different regulatory approaches. She proposes, "If the evidence continues to show that branched isomers don't bioaccumulate as much as linear, we could start designing molecules with branched structures."
Conclusion
The journey through the food web, from fish to birds, highlights the complex distribution of PFAS isomers. As we continue to unravel these mysteries, the potential for regulatory changes and innovative molecular design becomes increasingly apparent. The implications of these findings are far-reaching and deserve further exploration and discussion.
