While PFC toxicology studies have not yet been conducted on turtles, the levels of the compounds seen in all five species approach the amounts known to cause adverse health effects in other animals.
PFCs are man-made compounds that have many uses including stain-resistant coatings, fire-fighting foams and emulsifiers in plastics manufacturing. They have become widespread pollutants, are detectable in human and wildlife samples worldwide, infiltrate food chains, and have been shown in laboratory animals—rats, mice and fish—to be toxic to the liver, the thyroid, neurobehavioral function and the immune system. The PFCs most commonly found in the environment are perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Located in Charleston, S.C., the HML is a collaboration of the National Institute of Standards and Technology (NIST), the National Oceanic and Atmospheric Administration (NOAA), the South Carolina Department of Natural Resources, the College of Charleston and the Medical University of South Carolina.
"In our experiment, we wanted to accomplish two goals," says NIST research biologist and study lead Jennifer Keller. "We wanted to get the first accurate measurements of the plasma blood concentrations of PFCs in five sea turtle species across different trophic [food chain] levels, and then compare those concentrations to ones known to cause toxic effects in laboratory animals. That way, we could estimate the potential health risks from PFC exposure for all five turtles."
The five sea turtle species studied were the green, hawksbill, leatherback, loggerhead and Kemp's ridley. Their preferred diets range up the food chain from the green's sea grasses and algae to the crabs favored by the Kemp's ridley. The researchers expected that the PFC concentrations would be higher in species that fed farther up the food chain, since their prey's tissues would probably concentrate the pollutants.
This was generally the case. Plant-eating green turtles had the lowest plasma concentrations for the majority of PFCs examined, especially PFOS. As expected, leatherbacks, loggerheads and Kemp's ridleys had progressively higher PFOS concentrations. Surprisingly, however, hawksbills—who browse low on the food chain, primarily on sponges—recorded the second-highest average concentration of PFOS and were the only species to have a detectable PFOA level. The researchers surmise that this may relate to the locations where the hawksbills forage, or it may suggest that sponges have unusually high concentrations of PFOS and PFOA.
In the second part of the study, Keller and her colleagues compared the plasma concentrations of PFOS that they found in the five sea turtle species with previously reported concentrations that were shown to have adverse health effects in laboratory animals. The results showed that hawksbills, loggerheads and Kemp's ridleys had PFOS concentrations approaching those linked to liver and neurobehavioral toxicity in other animals; levels in loggerheads and Kemp's ridleys approached those linked to thyroid disruption in other animals; and all five species had levels that approached those linked to suppressed immunity in other animals.
"Better understanding the threat of PFCs, especially PFOS, to sea turtles can help wildlife managers and others develop strategies to deal with potential health problems," Keller says. "Our study provides the first baseline data in this area but more research is needed—especially for hawksbills after seeing their unexpectedly high PFC exposure."
Researchers from the College of Charleston's Grice Marine Laboratory, NOAA's National Marine Fisheries Service and the Loggerhead Marinelife Center also contributed to the study.
* J.M. Keller, L. Ngai, J.B. McNeill, L.D. Wood, K.R. Stewart, S.G. O'Connell and J.R. Kucklick. Perfluoroakyl contaminants in plasma of five sea turtle species: Comparisons in concentration and potential health risks. Environmental Toxicology and Chemistry, Vol. 31, No. 6, pp. 1223-1230 (June 2012). DOI: 10.1002/etc.1818
Michael E. Newman | EurekAlert!
Innovative grilling technique improves air quality
01.07.2020 | Fraunhofer Institute for Building Physics IBP
Traffic density, wind and air stratification influence the load of the air pollutant nitrogen dioxide
26.06.2020 | Leibniz-Institut für Troposphärenforschung e. V.
Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.
Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....
Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.
Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...
A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...
Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"
The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...
With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.
Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...
02.07.2020 | Event News
19.05.2020 | Event News
07.04.2020 | Event News
03.07.2020 | Life Sciences
03.07.2020 | Studies and Analyses
03.07.2020 | Power and Electrical Engineering