314
Long-Range Atmospheric and Marine Transport
A number of monitoring studies in the world have found the occurrence of PFASs
in water, air, biota, and soil in far-flung areas, e.g. the Arctic [146]. Long-range
transport of ionic PFASs, for example, the sulfonic and carboxylic acids (PFSAs
and PFCAs), occurs most of the time through the aquatic environment, and sometimes via oceanic currents. Whereas the long-range transport of neutral PFASs, for
example, the precursors called fluorotelomer alcohols (FTOHs), happens through
the atmospheric route [147]. They possess properties helping in long-range transport by allowing enough residence time in the atmosphere and simultaneously they
are so reactive that they are easily convertible into carboxylic acids and other products such as fluorotelomer species by undergoing oxidative reactions [147].
A study performed on the marine samples taken from the east coast of Greenland
demonstrated the presence of PFAS concentration in 150–250 pg/L range. The most
important single constituent of total PFAS was found to be PFOA with other shortchain PFAS, for example, PFBS, PFHxA, and PFHxS also being found. Short-chain
PFASs accounting for about 50% of the total amount of PFAS were found in samples taken from closer to the coast. In contrast to this, PFOS was found abundant in
samples taken from distant to sea. So, short-chain PFSAs can have long-range transport to distant areas via water. However, the sub-component of the study performed
along the Atlantic transect showed continuously decreasing the concentration of
PFAS in the water samples moving in southern direction from English Channel
(>500 pg/L) towards the Equator (<100 pg/L). In the south of the equator, minimal
PFASs were detected in the samples [148]. A recent review by ENVIRON in 2014,
comprising of several monitoring studies showed the presence of 6:2 FTOH in distant areas. A transformation product of 6:2 FTOH, namely PFHxA was found in far
environments that showed its capability of long-range transportation [149].
Conclusion
Perfluoroalkyl substances (PFAS) comprise a group of extremely fluorinated aliphatic chemicals that contain one or more C atoms on which all the hydrogen substituents have been exchanged by F atoms. PFASs are commonly used in several
consumer and industrial goods. They are found everywhere, i.e. soil, air, and water.
PFASs have drawn much attention and certain PFASs are regulated or voluntarily
limited owing to bioaccumulation potential and their omnipresence in human blood.
Numerous experimental studies have suggested that PFAS are linked with metabolic disorders including obesity and insulin resistance. Their chronic exposure may
impair lipids and carbohydrates homeostasis, change in the composition of fatty
acid, and alter adipocyte differentiation and adipokine secretion. Additionally, they
also disturb thyroid hormone balance and show the estrogenic properties. These
hazardous effects are partially due to increased oxidative stress induced by
S. G. Niazi et al.
Long-Range Atmospheric and Marine Transport
A number of monitoring studies in the world have found the occurrence of PFASs
in water, air, biota, and soil in far-flung areas, e.g. the Arctic [146]. Long-range
transport of ionic PFASs, for example, the sulfonic and carboxylic acids (PFSAs
and PFCAs), occurs most of the time through the aquatic environment, and sometimes via oceanic currents. Whereas the long-range transport of neutral PFASs, for
example, the precursors called fluorotelomer alcohols (FTOHs), happens through
the atmospheric route [147]. They possess properties helping in long-range transport by allowing enough residence time in the atmosphere and simultaneously they
are so reactive that they are easily convertible into carboxylic acids and other products such as fluorotelomer species by undergoing oxidative reactions [147].
A study performed on the marine samples taken from the east coast of Greenland
demonstrated the presence of PFAS concentration in 150–250 pg/L range. The most
important single constituent of total PFAS was found to be PFOA with other shortchain PFAS, for example, PFBS, PFHxA, and PFHxS also being found. Short-chain
PFASs accounting for about 50% of the total amount of PFAS were found in samples taken from closer to the coast. In contrast to this, PFOS was found abundant in
samples taken from distant to sea. So, short-chain PFSAs can have long-range transport to distant areas via water. However, the sub-component of the study performed
along the Atlantic transect showed continuously decreasing the concentration of
PFAS in the water samples moving in southern direction from English Channel
(>500 pg/L) towards the Equator (<100 pg/L). In the south of the equator, minimal
PFASs were detected in the samples [148]. A recent review by ENVIRON in 2014,
comprising of several monitoring studies showed the presence of 6:2 FTOH in distant areas. A transformation product of 6:2 FTOH, namely PFHxA was found in far
environments that showed its capability of long-range transportation [149].
Conclusion
Perfluoroalkyl substances (PFAS) comprise a group of extremely fluorinated aliphatic chemicals that contain one or more C atoms on which all the hydrogen substituents have been exchanged by F atoms. PFASs are commonly used in several
consumer and industrial goods. They are found everywhere, i.e. soil, air, and water.
PFASs have drawn much attention and certain PFASs are regulated or voluntarily
limited owing to bioaccumulation potential and their omnipresence in human blood.
Numerous experimental studies have suggested that PFAS are linked with metabolic disorders including obesity and insulin resistance. Their chronic exposure may
impair lipids and carbohydrates homeostasis, change in the composition of fatty
acid, and alter adipocyte differentiation and adipokine secretion. Additionally, they
also disturb thyroid hormone balance and show the estrogenic properties. These
hazardous effects are partially due to increased oxidative stress induced by
S. G. Niazi et al.