As it turns out, what we don’t know can hurt us.

Perfluorooctanesulfonic acid or perfluorooctane sulfonate (PFOS) is quite the mouthful and while, like me, you may have difficulty pronouncing it, chances are you, along with almost all of your surrounding aquatic environments, are home to these chemicals.  A potential problem considering that recent research has a number of scientists concerned about the prevelance, persistence and toxicity of PFOS in our ecosystems.

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Chemical model of PFOS. Source: http://en.wikipedia.org/wiki/Fluorosurfactant

PFOS were most famously used as a key ingredient in Scotchgard and other products that put the unique property of repelling both water and oil to use (other stain repellents, surface protectors in carpets, leather, paper, food containers, fabric, upholstery, fire-fighting foams, floor polishes, shampoos, adhesives, paints, pesticides, etc.).  Manufactured largely by a company called 3M since 1956, production stopped in 2002 after scientists found that PFOS were accumulating in water, wildlife and people.

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3M Company has switched from PFOS and PFOA to other perfluorinated compounds in its products. Source: http://sierravoices.com/2014/10/fish-still-contaminated-with-phased-out-scotchgard-chemical/

To demonstrate just how persistent and widespread PFOS are in our aquatic environments a recent study by the United States Environmental Protection Agency found PFOS in all 157 fish of various species sampled in five of the Great Lakes (that’s 100%) and 73% of fish from 162 rivers.  This comes 12 years after these chemicals were largely discontinued in the United States.  The primary reason for the widespread and persistent nature of PFOS is that these chemicals do not seem to degrade or break-down in the environment.

Perfluorochemical-Testing

Fire fighting foams were and still are a source of PFOS in some places Source: http://www.caslab.com/PFOA-PFOS/

While we are just beginning to understand how PFOS affect aquatic species, results so far suggest a range of negative consequences. Some scientists have found that short-term exposure to PFOS can lead to higher energy use in goldfish and carp.  This result may seem minor but when energy is being used to deal with the internal stress that PFOS cause, that energy cannot be used for growth or survival.

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Smallmouth bass are one of the many fish contaminated by PFOS in US rivers and the Great Lakes. Source: http://www.environmentalhealthnews.org/ehs/news/2014/sep/pfos-in-waters

PFOS have also been seen to weaken the immune system of fish larvae, increasing their susceptibility to infectious disease. More seriously, a study examining the effects of long-term PFOS exposure found that female fish exposed to the highest concentration of PFOS had offspring that were severely deformed and resulted in 100% mortality.

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Because PFOS are bioaccumulative (or are transferred through diet and increases up the food web), eating contaminated fish are likely a source of PFOS in people. Also, while the USEPA has not established a ‘safe dose’ of PFOS, Minnesota health officials have set consumption recommendations and issued consumption advisories. Source: http://www.environmentalhealthnews.org/ehs/news/2014/sep/pfos-in-waters

Research on mammals have also related PFOS to a litany of wildlife and human health concerns (reduced immune system function, kidney disease, preeclampsia, low birth weights, and others).  As such, PFOS were added to the Stockholm Convention on Persistent Organic Pollutants, an international treaty to restrict or eliminate the use of particular chemicals, in 2009.

PFOS are a testament to the importance of truly understanding the toxicity and impact of a manufactured chemical before its widespread use.  After all, ‘an once of prevention is worth a pound of cure’; although here ‘a pound of cure’ may not seem like a sufficient description for the costly damage PFOS have and will likely cause to ourselves and our aquatic ecosystems.

By: Dana Sackett

References and additional material:

Anoop S, Xiao J, Ducatman A (2011) Perfluoroalkyl chemicals and chronic kidney disease in US adults.  American Journal of Epidemiology 174: 893–900.

Fang C, Huang Q, Ye T, Chen Y, Liu L, et al. Embryonic exposure to PFOS induces immunosuppression in the fish larvae of marine medaka. Ecotoxicology and environmental safety 92: 104-111.

Hagenaars A, Knapen D, Meyer IJ, van der Ven K, De Coen W. (2008) Toxicity evaluation of perfluorooctane sulfonate (PFOS) in the liver of common carp (Cyrinus carpio). Aquatic Toxicology 88: 155-163.

Hu J, Yu J, Tanaka S, Fujii S. (2011) Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) in Water Environment of Singapore. Water Air Soil Pollut 216:179–191

Taniyasu S , Kannan K, Horri Y, Hanari N, Yamashita N. (2003) Survey of Perfluorooctane Sulfonate and Related Perfluorinated Organic Compounds in Water, Fish, Birds, and Humans from Japan. Environ. Sci. Technol. 37: 2634-2639.

Wang M, Chen J, Lin K, Chen Y, Hu W, Tanguay R, Huang C, Dong Q. (2011) Chronic Zebrafish PFOS Exposure alters sex ratio and maternal related effects in F1 offspring. Environmental Toxicology and Chemistry 30: 2073–2080.

Xia J, Fu S, Cao Z, Peng J, Peng J, Dai T, Cheng L. (2013) Ecotoxicological effects of waterborne PFOS exposure on swimming performance and energy expenditure in juvenile goldfish (Carassius auratus).  Journal of Environmental Sciences 25: 1672–1679.

http://www.sciencedaily.com/releases/2008/04/080430203049.htm

http://www.ourstolenfuture.org/newscience/oncompounds/pfos/2001-04pfosproblems.htm

http://www.environmentalhealthnews.org/ehs/news/2014/sep/pfos-in-waters

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