Perfluorooctane Sulfonate, or PFOS is a synthetically produced organic molecule used in many household products including lubricants, polishes, adhesives, paints, fire fighting foams, and many more. This molecule is highly fluorinated, leading to its persistence once it is introduced into the environment. This becomes a problem to both terrestrial and marine species as PFOS is carried by wind and may find it self in even the most remote places in the world (Some Alaskan coastal waters). This brings me to a current study that measured amounts of PFOS in marine mammals.
The scientists wanted to measure PFOS concentrations in marine mammals from many different bodies of water in an effort to gauge its distribution. 247 tissue samples from 15 different species of marine mammals were collected. Locations included the coastal waters of Florida, California, and Alaska, as well as the Northern Baltic Sea and the Arctic. The species analyzed included a pygmy sperm whale, four species of dolphins, two species of sea lions, six species of seals, polar bear, and the only freshwater species being a southern sea otter. Tissue samples were taken from the liver and the blood in marine species and were acquired from State agencies or university laboratories. The scientists didn’t test marine mammal blubber because PFOS is expected to repel oils/fats so it shouldn’t be found in the fat reserves. It was previously known that concentrations of PCB’s were found in seals in California coastal waters, so scientists expected to find concentrations of PFOS in animal tissue at this same location.
The scientists found that PFOS was in the liver and blood of marine mammals from most the locations. The greatest concentration of PFOS was in a bottlenose dolphin from Sarasota Bay, Fl. (1520 ng/g wet weight). The second highest concentration was found in a ringed seal from the Northern Baltic Sea (475 ng/ml wet weight). This result was unexpected as scientists thought pinnipeds (true seals) would have the lowest concentrations. This is because seals molt annually, which may eliminate compounds binding to structural proteins.
Overall, the results showed that even in the most remote areas (arctic), PFOS is showing its persistence. PFOS is a wind spread and wide spread chemical pollutant that scientists don't know much about. Although it is structurally similar to other fluorinated compounds, its effects have not been studied on wildlife. Future studies are needed in order to measure the effect this compound has on wildlife.
REFERENCE:
Kannon, K., Koistinen, J., Beckman, K., & Evans, T. (2001). Accumulation of perofluorooctane
sulfonate in marine mammals. Env. Science Technology, 35(8), 1593-1598. doi: 10.1021/es001873w
I find it really interesting that this compound would be found in the blood and not other hydrophobic parts of the animal's body. Looking up more info, it said that PFOS is repelled by both polar and non-polar materials, and the log Kow can't be measured. Looks like there needs to be more research on PFOS!
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