Perfluorinated Chemicals in Drinking and ... - ACS Publications

Chapter 13

Downloaded by COLUMBIA UNIV on June 26, 2012 | http://pubs.acs.org Publication Date (Web): November 2, 2010 | doi: 10.1021/bk-2010-1048.ch013

Perfluorinated Chemicals in Drinking and Environmental Waters Paul C. Rumsby,* Wendy F. Young, Tom Hall, and Clare L. McLaughlin National Centre for Environmental Toxicology, WRc plc, Frankland Road, Swindon SN5 8YF, UK *[email protected]

Perfluorinated chemicals (PFCs) have been used for many years as surfactants in a variety of industrial and consumer products with the main ones being perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA). However, owing to their persistent, bioaccumulative and toxic (PBT) characteristics, PFOS has been phased out by its principal producer and the use of PFOA has been severely reduced. In their place, a number of newer PFCs are being introduced and, while they appear to have a shorter persistence in humans and the environment, their toxicity is at present uncertain and further studies are required. Recent monitoring studies suggest that these other newer PFCs and previously unmonitored breakdown products, are detected in environmental waters, in some cases at levels similar to those of PFOS and PFOA. Some new data are described which indicate that PFOS, PFOA and other PFCs can be removed by granular activated carbon absorption, such as that seen in advanced drinking water treatment, under appropriate controlled conditions, although these conditions vary with different PFCs. The data suggest that the toxicology of PFCs is complex with PFOS and PFOA having different effects at varying concentrations in different species. Cancer, developmental delays, endocrine disruption, immunotoxicity and neonatal mortality are all potential toxic endpoints. Contamination and occupational exposure have led to a number of ongoing epidemiological studies in populations exposed to high levels © 2010 American Chemical Society In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

of PFOS or PFOA, as well as on those with background exposure. Many of these studies are examining reproductive and developmental endpoints. The work is ongoing but at present, the results are inconsistent with only small effects, if any, being observed in populations exposed to high levels of PFOA. Monitoring suggests that, although PFOS and PFOA are persistent, controls on their manufacture and use since 2000 have led to a decrease in their presence in the human population and the environment.


Manufacture and Usage Perfluorooctane sulphonate (PFOS; Figure 1) perfluorooctanoic acid (PFOA; Figure 1) and related compounds are members of a large family of perfluorinated chemicals (PFCs) that have been produced for at least 50 years. These PFCs have been increasingly used as surfactants in a number of industrial and consumer products, mainly to repel dirt, water and oils (1). Their use has included performance chemicals such as photographic film, surfactant in fire-fighting foams, surfactant for alkaline cleaners, emulsifiers in floor polish, mist suppressant for metal plating baths, surfactant for etching acids for circuit boards, pesticides, and dirt repellent treatments for textiles (e.g. carpets, home furnishings and leather) and paper (e.g. food containers and masking tape). PFOS-related chemicals are manufactured from a precursor material known as perfluorooctanesulphonyl fluoride (POSF). It has been estimated that the total global production/use (from 1970-2002) has been 96 000 tonnes of POSF with total global emissions being 650-2600 tonnes of POSF and 6.5-130 tonnes of PFOS. Most of the environmental release is to water (98%) and the remainder to air (2). They are immobile in soil and are non-biodegradable in, for example, activated sewage sludge (1). PFOS is actually a degradation product of perfluorooctane sulphonamide derivatives (such as perfluoroalkyl sulphonamidoethanols; Figure 1), components of the original stain protection product Scotchguard, made by 3M (3). In the year 2000, between 3665 and 4500 tonnes of POSF were produced globally, and 3M was the dominant producer. In that year, 3M announced that they would phase out the use of POSF after data revealed that PFCs are extremely persistent in the environment, are bioaccumulative, and pose a risk to the environment and human health. Global production and use by 3M ceased in 2001. 3M also phased out production of PFOS, PFOA and related chemicals by 2002. However, other manufacturers have filled the deficit of 300 tonnes/year production of the ammonium salt of PFOA. In 2006, the European Union announced severe restriction on the use of PFOS, with member states adopting national measures by June 2008. PFOS cannot be placed on the market or used as a substance or constituent of preparations in a concentration equal to or higher than 0.005% by mass, or 0.1% in semi-finished articles or preparations, or 1 µg/m2 in textiles and coated material (4). Exemptions to this restriction include its use in anti-reflective coatings for photolithography, 276 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.


Figure 1. Structure of some PFCs mist suppressants for non-decorative hard chromium (VI) plating and hydraulic fuels for aviation. However, any PFOS-containing fire-fighting foams in existence are still permitted for use until mid-2011. 277 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

PFOA has been a component in surfactants used in the production of DuPont’s Teflon and is also a degradation product of long chain fluorotelomer alcohols (such as 8:2 fluorotelomer alcohol; Figure 1; (3)).


Persistence, Bioaccumulation and Toxicity It has become clear in the last few years that PFCs are very persistent in the environment. The chemical nature of fluorine means that the carbon-fluoride bond is the strongest found in nature, making fluorinated compounds resistant to chemical and biochemical reactions. Fluorinated compounds are stable against many degradation processes found in the environment such as hydrolysis, photolysis, acid and basic attacks, oxidising and reducing agents, and biodegradation (5). PFCs have been shown to bioaccumulate in animals, including humans. Traces of PFCs are found in blood (where they bind to serum proteins) and organs such as liver and kidneys, as well as in muscle tissue. This is in contrast to other persistent organic pollutants (e.g. polychlorinated biphenols), which are lipophilic and tend to accumulate in the fatty tissues. PFCs have been detected globally in the environment, having been found in polar bears in Greenland, giant pandas in China and albatrosses in the middle of the Pacific Ocean (6). This suggests atmospheric transport of these compounds, although their potential to volatilise is low. However, PFOS and PFOA seem more prevalent in the more industrial areas such as the Baltic Sea, The Mediterranean, the Great Lakes and along Asian coasts (5). There is some evidence that in humans, blood concentrations of PFOS and, to a lesser extent, PFOA, have declined from 2000. Olsen et al. (7) using plasma samples from Minnesota American Red Cross blood donors have shown, in a small sample, that PFOS levels have decreased from 2000 (33.1 ng/l geometric mean) to 2005 (15.1 ng/ml). The geometric mean for PFOA was 4.5 ng/ml in 2000 and 2.2 ng/ml in 2005. The decline in PFOS and PFOA levels may be due to the phase-out of POSF by the principal global manufacturer, 3M, in 2000-2002 and the reduction in the use of PFOA. Although the acute toxicity of PFCs is moderate, its persistence in the body (average half-life for PFOA in humans of 3.5 years and up to 8.7 years has been determined in retired production workers) has led to increasing concerns over long-term effects. The toxicity of PFOS and PFOA is not clearly understood at present (reviewed in (6, 8)). Different animal species appear to have different sensitivities to these compounds which make interpretation of experiments difficult, (e.g. Rhesus monkeys are more sensitive to PFOS than rats, while mice are the least sensitive). The species variability may be due to the different handling of these compounds in the body. At present, it is unclear whether PFOS and PFOA act by the same mechanisms, and high and low doses may differ in their toxic endpoints and effects. High dose studies on animals have indicated that cancer, developmental delays, endocrine disruption, immunotoxicity and neonatal mortality are potential toxic endpoints. Recent research has also suggested that receptor binding may be an important general mechanism. PFOS and PFOA both 278 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

bind to peroxisomal proliferator-activated receptor (PPAR). Activation of such receptors may alter fatty acid metabolism and play a role in cancer, foetal growth, and hormone and immune functions (reviewed in (6, 8, 9)). There have recently been a number of human studies published looking at toxicological endpoints in populations exposed to both background and increased levels of PFCs, particularly of PFOA. The increased exposure is mainly in workers involved in the manufacture of PFCs and neighbouring populations to plants where contamination incidents have occurred (see below).


Contamination Incidents The presence of PFCs and in particular PFOS and PFOA in environmental waters has been the subject of much interest in recent years. Important information has emerged following contamination incidents: in the USA, Germany and the UK.

USA Little Hocking, West Virginia PFOA has been detected in the drinking water supply of Little Hocking near Washington, West Virginia, USA (10, 11). This village is across the Ohio River from and downwind of the Dupont fluoropolymer manufacturing facility. The extent of exposure to residents of the village was assessed by questionnaire and measuring PFOA in blood samples. Levels of PFOA in drinking water averaged 3.55 µg/l during 2002-2005. The blood PFOA levels were 60-75 times higher than in the general population. Serum PFOA was particularly high in individuals who consumed more home-grown fruit and vegetables. It is unclear whether PFOA was present in the produce itself or in water used for cooking. A further study on the exposure of residents living near this facility (11) used historical emission records for 52 years to estimate the potential intake of 50 000 residents. PFOA detected in groundwater was deemed to have originated by particulate deposition from air emissions to the soil and then transfer to the water. Maximum concentrations were estimated to occur at up to one mile from the site, with maximum air, surface soil and drinking water levels estimated to be 200 ng/m3, 11 µg/kg and 4 µg/l, respectively. An independent team of scientists, C8 Assessment of Toxicity Team (CATT), has been assembled to conducted human health and ecological risk assessments and communicate health risk information to the public. Their preliminary risk assessment concluded that average daily intakes of PFOA within 5 miles of the plant over a 50 year time span was 10 000 less than an intake that was not considered a risk to human health (11). The contaminated population in this area has been further assessed in a number of ongoing epidemiological studies, the results of some of which have recently been published. 279 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.


Nolan et al. (12) compared birth weights and gestational ages of neonates born to mothers residing in zip codes with water supplies provided completely, partially or not at all by the Little Hocking Water Association (LHWA) The incidence of low birth weight, preterm birth, mean birth weight and mean gestational age of neonates did not significantly differ among water service categories. The authors concluded that markedly elevated PFOA exposure was not associated with any increased risk of lowered birth weight or gestational age. Stein et al. (13) examined the association of serum PFOA and PFOS with self-reported pregnancy outcome in a similar population highly exposed to PFOA. Data on birth outcomes were compared to serum PFOA and PFOS levels for 1845 and 5262 pregnancies, respectively. Neither serum PFOA nor PFOS showed any association with miscarriage or preterm birth. There was a modest association of serum PFOA with preeclampsia and birth defects, and of serum PFOS with preeclampsia and low birth weight. However, associations were small, limited in precision, and based solely on self-reported health outcomes and so, while there was an association, no firm conclusion could be drawn. Nolan et al. (14) examined the associations between PFOA exposure, congenital anomalies, labour and delivery complications, and maternal risk factors in neonates and their mothers exposed to PFOA-contaminated residential drinking water from the Little Hocking Water Association (LHWA). Increased PFOA exposure was not associated with an overall increase in the likelihood of congenital anomalies nor any specific diagnosis and delivery complications and maternal risk factors. Therefore it appears that any effects on reproduction and development from increased exposure to PFOA are very small. Olsen et al. (15) recently qualitatively reviewed the published epidemiologic literature as to the potential association of exposure to PFOS and PFOA with human foetal development. The published research has focused on birth weight and other measurements that reflect human foetal development. A total of eight epidemiologic studies were reviewed that focused on six general (non-occupational) and two occupational populations. Of the six general population studies, five examined associations between birth weight and other anthropometric measurements in relation to maternal blood and/or umbilical cord concentrations of PFOS and PFOA. In the sixth study, three geographical areas in Washington County, Ohio (Little Hocking), were categorized by their public drinking water sources that contained PFOA and which had resulted in higher serum concentrations than observed in other general population studies. The occupational studies focused on another perfluorochemical manufacturing site (Decatur, Alabama, see below), with exposure categorized from work history and biomonitoring data. There were inconsistent associations reported for several different birth outcomes, including birth weight, birth length, head circumference, and ponderal index, among the five general population studies that measured PFOS and PFOA in the study subjects (16, 17). No association with birth weight or gestational age was reported in the community drinking water study (see above; (12)). Only one general population study examined infant Apgar scores and developmental milestones at 6 and 18 months of age, with no associations reported. No association with self-reported 280 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.


birth weight and occupational exposure to PFOS materials was observed among female perfluorochemical production workers. There have also been two Danish epidemiological studies (18, 19) investigating the association between plasma levels of PFOS and PFOA in pregnant women and motor and mental developmental milestones of their children and time to pregnancy (fecundity). The authors found no convincing associations between developmental milestones in early childhood and levels of PFOA or PFOS as measured in maternal plasma early in pregnancy, but did find some reduction in fecundity at levels of plasma PFOS and PFOA seen in the general population in developed countries. There has also been a further small Danish study which found that high serum PFOS and PFOA levels were associated with fewer normal sperm, although the authors indicated that their findings would need to be corroborated in larger studies (20). There is a further ongoing study in residents of Little Hocking (21). It is investigating the relationship between serum PFOA and PFOS concentrations and total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), the ratio of total cholesterol to HDL, and triglycerides. In multivariate models adjusting for other factors, all lipid outcomes except HDL were higher when serum PFOA and PFOS were higher. The odds ratio for high cholesterol (defined by ≥ 240 mg/dl), by increasing quartile of serum PFOA concentration, were 1, 1.21, 1.33 and 1.4, respectively. The corresponding adjusted odds ratio by quartile of PFOS, were 1, 1.13, 1.28 and 1.51, respectively. These odd ratios indicated that those with serum levels in the top 25% of the two chemicals had a 40-50% increased risk of having high cholesterol compared to those in the lowest 25%. The C8 Science Panel will only assess if a probable link to the disease exists when all the relevant data have been collected and analysed, which is expected to be completed in 2011. A recent paper, using data from the US Health and Nutrition Examination Survey (NHANES), found an association between the highest levels of PFOS and PFOA in the general population and current thyroid disease (22). Effects on the thyroid have been observed in animal studies on PFOS and PFOA. This endpoint is also being examined in the Little Hocking population exposed to much higher concentrations of PFOA and the results of this study will clarify this finding.

Cottage Grove, Minnesota 3M produced PFCs at a site in Cottage Grove, Minnesota, from the late 1940s until 2002 (23). During this time, there were air emissions of PFCs, waste from production was deposited in an on-site pit, and wastewater treatment plant effluent containing PFCs was discharged into the nearby Mississippi River. There was also a fire-training area on site where PFC-containing foams were used. Monitoring indicates that groundwater beneath the site was contaminated with PFOS and PFOA at significant levels (PFOS and PFOA concentrations up to 120 µg/l and 105 µg/l, respectively). Much of this contaminated groundwater was then processed through the wastewater plant on site which was unable to remove PFCs. However, more recently (approximately 2004 onwards), the addition of a 281 In Contaminants of Emerging Concern in the Environment: Ecological and Human Health Considerations; Halden, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

large granular activated carbon (GAC) system has eliminated PFC discharge into the Mississippi River.


Decatur, Alabama A further 3M PFC production plant is situated in Decatur, Alabama. Monitoring of the nearby Tennessee River upstream and downstream of this plant showed PFOS present throughout the 80-mile stretch of the river studied, with levels of 32+/-11 ng/l upstream of the facility and 114+/-19 ng/l downstream. Concentrations of PFOA were below the level of detection upstream, but 394+/-128 ng/l downstream (24)(Hansen et al., 2004). Workers at this plant have also been the subject of epidemiological studies on reproductive and developmental outcomes (reviewed by Olsen et al. (15); see above). Germany In the summer of 2006, 12 perfluorinated surfactants were sampled in various surface water and drinking waters in Germany (25). Surface water sampled included the rivers Rhine, Ruhr and Moehne as well as some of their tributaries, whilst the drinking water samples were from public buildings in the Rhine-Ruhr area. The sum of the seven compounds most frequently found in the River Rhine and its tributaries was

Perfluorinated Chemicals in Drinking and ... - ACS Publications

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