The Effect Of Perfluorooctane Sulfonate On The Environment

Perfluorooctane sulfonate (C8F17SO3) also known as PFOS has become an increasing concern in the environment due to its unique physical, chemical and biological properties. (Kunacehva et al. 2014) PFOS belongs to a class of organic compounds known as Persistent organic pollutants (POPs) that are responsible for being bio-accumulated and toxic not only to wildlife but humans as well. (Xiao et al. 2015) These distinctive properties of organofluorine molecule arise from its carbon-fluorine bond; fluorine being the most electronegative element, attracts electrons towards itself conferring a highly stable chemical bond. (Kunacehva et al. 2014) PFOS is seen around the world in industrial and commercial applications to produce everyday household items such as carpets, paper packaging, textile, cleaning products, insecticides, and a major product being Scotch Guard. (Kunacheva et al. 2014). This paper will summarize the lecture given by John P. Giesy at UOIT on the effect of PFOS in the environment.

Perfluorooctane sulfonate (PFOS) is a growing concern in today's society. (Giesy and Kurunthachalam 2002). It is occurring globally, environmentally persistent, bioaccumulative and can be potentially detrimental. (Xiao et al. 2015; Wang 2016). Just like DDT, PCBs, and Chloro-fluorocarbons, PFOS was once invented for safety and thought to be very useful at one point in time, but is now considered to be a terminal degradation product of a number of chemicals. (2014 lecture by J. Geisy from UOIT; unreferenced). This compound has a special amphiphilic property making it very useful in many of the products we still use today, such as the paper coating of microwavable popcorn, surface treatment, and hamburger wrappers that are all permeated with chemicals that could be degraded to PFOS. (2014 lecture by J. Geisy from UOIT; unreferenced) Two important factors with PFOS is that it is very water soluble and not very volatile. (2014 lecture by J. Geisy from UOIT; unreferenced). PFOS is fundamentally different from all organochlorines that we know about. (2014 lecture by J. Geisy from UOIT; unreferenced). They are very thermally stable, resistant to hydrolysis, photolysis and don’t degrade in the environment rendering them environmentally persistent. (Giesy and Kurunthachalam 2002). But this is one of the reasons that make them useful.

They don't partition into fat as DDT does. (2014 lecture by J. Geisy from UOIT; unreferenced). PFOS can get into the environment in two ways. One way being PFOS was always put into products linked to something else. (2014 lecture by J. Geisy from UOIT; unreferenced) The PFOS moiety is incorporated in a wide variety of compounds that have the possibility to degrade back into PFOS in the environment. (2014 lecture by J. Geisy from UOIT; unreferenced). But due to the Toxic substance control act (TCSA), the polymer exclusion clause stated that if certain perfluoroalkyl moieties are long-chain polymers, they’re considered inert and can’t get inside animals or people so they’re exempt from a lot of environmental testing. (2014 lecture by J. Geisy from UOIT; unreferenced). So, for example, when you put a carpet into a new house 1-3% of the polymer is not bound, and can be volatized out and in fact, move around the globe. (2014 lecture by J. Geisy from UOIT; unreferenced) Some of the highest concentrations of PFOS are seen in polar bear (>4000 ng/g) and seals (37 ng/g) in the artic where PFOS can move by long-range atmospheric transport and once it gets into an animal can metabolize very quickly back into PFOS and excreted as urine and feces which is soluble in water and therefore bioaccumulate. (2014 lecture by J. Geisy from UOIT; unreferenced)

The other way PFOS can get into the environment is by the release of the materials while they’re being manufactured before their applied in their final applications. (2014 lecture by J. Geisy from UOIT; unreferenced) Now in Canada, 87 different chemicals containing PFOS have now been band resulting in a significant decrease in the concentrations of PFOS in the environment. (2014 lecture by J. Geisy from UOIT; unreferenced). In conclusion, once always thought to be an inert chemical, according to the lecture and study done by Giesy (2014), PFOS is ubiquitous in the global environment, accumulates into human and wildlife tissues, is seen in a wide variety of products and due to its unique physical, biological and chemical properties may be entering the environment either by degradation of its moieties or while it's being manufactured. This may result in having potentially immediate or long-term harmful effects that may be toxic to invertebrates and vertebrates as they can travel over a long range of atmospheric transport and bioaccumulate.