Environmental Engineering Reference
In-Depth Information
stances, although at high concentrations, they have been associated with a wasting syn-
drome that disrupts lipid metabolism and enlarges the liver. Because PFAS do not parti-
tion into fatty tissue, it was not expected that they would be capable of biomagnification.
However, the AMAP 2009 assessment team reported that some studies do suggest a degree
of biomagnification in the Arctic, leading up to fish-eating whales and seabirds. Müller and
colleagues have provided a recent example. They measured the biomagnification of PFAS
in the lichen-caribou-wolf food chain involving the Porcupine and Bathurst caribou herds
of western Arctic Canada. The lowest concentrations were found in vegetation and the
highest in the wolf population. Biomagnification factors were highly tissue and substance
specific.Therefore,individualwholebodyconcentrationswerecalculatedandusedforbio-
magnification and trophic magnification assessment. Trophic magnification factors varied
but were highest for PFAS that contained 9-11 carbon atoms. Finally, we find that PFAS
are also present in Inuit. A study published in 2012 by Lindh and colleagues found that
blood serum levels of seven types of PFAS in Greenland Inuit were amongst the highest
found in a general population anywhere in the world.
Incidentally, we should not have been surprised that brominated and fluorinated sub-
stances behave in such a similar way to organochlorines. Fluorine, chlorine and bromine sit
together in the same group in the Periodic Table. You will probably have already noticed
that some lessons were learned here. According to our understanding of POPs when the
CLRTAP POPs protocol and the Stockholm Convention were being negotiated, the PFAS
family shouldnothavecreated anyenvironmental problems.Theprocedureforaddingnew
substances to the two agreements was based largely on two notions. First is the idea that to
be a global problem, a substance should be able to enter the atmosphere at warm temperat-
ures and to leave it at cold temperatures. In other words, a substance must be semivolatile.
Second, for the substance to reach toxic levels in biota far from source, it would have to
be capable of biomagnification, a process that depends (or so we thought) on the substance
being fat soluble. Therefore, you could use predictive criteria for volatility and fat solubil-
ity to ascertain whether a substance qualified as a POP without waiting for the substance to
accumulate in remote cold areas. The PFAS family failed both of the predictive criteria but
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