Draft Ecological Screening Assessment Report Long-Chain (C9–C20) Perfluorocarboxylic Acids, their Salts and their Precursors

Under the Canadian Environmental Protection Act, 1999, the Ministers of the Environment and of Health conducted an ecological screening assessment of Long-Chain (C9-C20) Perfluorocarboxylic Acids, their Salts, and their Precursors which were identified as emerging chemicals of concern. Empirical evidence demonstrated that some perfluorocarboxylic acids are bioaccumulative, persistent, subject to long-range transport (via precursors), widespread and showing a trend toward increasing concentrations in Arctic wildlife. The fact that some of the precursors to the long-chain (C9-C20) perfluorocarboxylic acids are also structurally similar to the four fluorotelomer-based substances prohibited by the Minister of the Environment under the authority of section 84 of the Canadian Environmental Protection Act, 1999 has contributed to the decision to undertake this ecological screening assessment of the long-chain (C9-C20) perfluorocarboxylic acids. As well, fourteen precursors (listed in Appendix I) were deemed to meet the categorization criteria under Section 73 of the Act.

This ecological assessment focuses on the perfluorocarboxylic acids with carbon chain lengths from 9 to 20 inclusive, their salts and their precursors. Precursors, i.e., substances that could transform or degrade to long-chain (C9-C20) perfluorocarboxylic acids, were considered on the basis of their contribution to the total presence of long-chain (C9-C20) perfluorocarboxylic acids in the environment. This assessment defines precursors as any substances where the perfluorinated alkyl moiety has the formula C_nF_2n+1 (where 8=n=20) and is directly bonded to any chemical moiety other than a fluorine, chlorine or bromine atom.

The presence of long-chain perfluorocarboxylic acids, their salts and their precursors result from anthropogenic activity. In 2000 and 2004, industry surveys by Environment Canada under the authority of section 71 of the Canadian Environmental Protection Act, 1999 found that long-chain (C9-C20) perfluorocarboxylic acids were not reported to be manufactured or imported into Canada. However, in both surveys, several precursors to the long-chain (C9-C20) perfluorocarboxylic acids were reported to be imported into Canada.

In traditional toxicity studies, long-chain (C9-C20) perfluorocarboxylic acids were found to be low to moderately toxic, with acute toxicity values ranging from 8.8 to 285 mg/L. There are two studies on the toxicity of long-chain (C9-C20) perfluorocarboxylic acids in terrestrial species. In one study, no adverse effects were observed up to 1.0 mg/kg body weight for male chickens dosed with C10 perfluorocarboxylic acid. In another study, a soil-dwelling nematode showed acute lethality at 306 mg/L and multi-generation effects (decreased fecundity) at 0.000464 mg/L when exposed to C9 perfluorocarboxylic acid.

There are other studies showing the potential for long-chain (C9-C20) perfluorocarboxylic acids to cause other types of effects. For example, although a direct causal relationship has not been demonstrated, liver lesions have been observed in wild polar bears cumulatively exposed to several long-chain perfluorocarboxylic acids. C9 and C10 perfluorocarboxylic acids have been shown to affect the multi-xenobiotic resistance mechanism in marine mussels at concentrations ranging from 2.23 to 3.65 mg/L. C9 to C12 perfluorocarboxylic acids induced vitellogenesis in rainbow trout at 2.56 x 10^-5 to 2 mg/g diet. C9 perfluorocarboxylic acid may cause oxidative stress in the common cormorant. C9 to C11 perfluorcarboxylic acids activated the mammalian peroxisome proliferator–activated receptor a (PPARa) in the livers of Baikal seals. PPARa plays a critical physiological role as a lipid sensor and a regulator of lipid metabolism. C9-C10 PFCAs are also chemical sensitizers for the marine mussel, Mytilus californianus, by allowing normally excluded toxic substances to accumulate in the marine mussel. C12 and C14 PFCAs increased the mitochondrial membrane potential in the freshwater alga, Scenedesmus obliquus, indicating damage to the mitochondrial function.

There are no experimental persistence data, under environmentally relevant conditions, available for the long-chain (C9-C20) perfluorocarboxylic acids. However, the carbon-fluorine bond is one of the strongest in nature, making the structure extremely stable and resistant to degradation. The perfluorinated chain provides exceptional resistance to thermal and chemical attack. Thus, due to the strength of the carbon-fluorine bond, it is expected that long-chain (C9-C20) perfluorocarboxylic acids would be persistent. Furthermore, long-chain perfluorocarboxylic acids have been detected in remote areas (e.g., the Canadian Arctic). While mechanisms of transport are not fully understood, certain precursors may undergo long-range transport to remote areas, where subsequent degradation can result in the formation of long-chain (C9-C20) perfluorocarboxylic acids.

A bioaccumulation factor (BAF) or bioconcentration factor (BCF) > 5000 has been demonstrated for C11, C12 and C14 perfluorocarboxylic acids. For C11, C12, and C14 perfluorocarboxylic acids, there is the potential for bioconcentration in fish (BCF > 5000) and some potential for biomagnification in fish and marine mammals. However, there remains a significant potential for biomagnification and/or trophic magnification in water-breathing and air-breathing organisms for all long-chain (C9-C20) perfluorocarboxylic acids. There are no experimental or predicted bioaccumulation data available for long-chain perfluorocarboxylic acids greater than C14, nevertheless, there is the potential that these longer chains could bioaccumulate or biomagnify in marine and/or terrestrial species based on chemical conformations. In addition, C15 perfluorocarboxylic acids have been measured in fish, invertebrates and polar bears.

C9 to C15 perfluorocarboxylic acids were measured in the liver of seals, foxes, fish, polar bears, Greenland shark, narwhals, beluga whales and birds either in the Canadian Arctic or the Great Lakes region. Concentrations ranged from below detection levels to 180 ng/g liver wet weight, with concentrations greatest for polar bears followed by Greenland shark, narwhals and beluga whales. Worldwide, C9 to C15 have been reported in ringed, fur and harbour seals, dolphins (i.e., white-sided, bottlenose, white-beaked, Franciscana, humpback), finless porpoises, glaucous gulls, sperm whale, beavers, Amur tigers, wild rats and several species of birds (little egret, little ringed plover, parrotbills, black-crowned herons). Concentrations ranged from below detection levels to 480 ng/g wet weight, with concentrations highest in the white-beaked dolphin.

From 1980 to 2000, levels of long-chain perfluorocarboxylic acids in ringed seal livers from Greenland increased 3.3 and 6.8% per year for C10 and C11, respectively. From 1992 to 2005, the mean concentrations of C9 and C10 PFCA in the livers of Baikal seals were 1.2 to 1.7-fold higher. From 1972 to 2002, mean doubling times for concentrations in polar bear livers from the Arctic ranged from 5.8 to 9.1 years for C9 to C11. From 1993 to 2004, concentrations in ringed seal liver samples increased, with a doubling time of 4 to 10 years for C9 to C12. In northern fulmar liver samples, C9 to C15 levels increased from 1987 to 1993 and remained steady from 1993 to 2003. Thick-billed murre liver samples showed an increase in C9 to C15 concentrations from 1975 to 2004. Concentrations of C9 to C13 increased significantly in whole eggs of herring gulls in Norway from 1983 to 1993. Male beluga whales from Nunavut showed an annual liver increase of 1.8 ng/g-ww for C9-C12 from 1980-2010.

Long chain (C9-C20) perfluorocarboxylic acids are persistent in the environment and can bioaccumulate and biomagnify in terrestrial and marine mammals. Given these inherent properties, together with environmental concentrations that may approach effect levels (including for vitellogenin induction), increasing temporal trends for several Arctic species (i.e., the polar bear, seals and Arctic birds), their widespread occurrence in biota likely due to the long-range atmospheric or oceanic transport of volatile precursors and/or the acids themselves, and the fact that other perfluorinated compounds and precursors to long-chain perfluorocarboxylic acids may contribute to the overall additive or synergistic impact of long-chain (C9-C20) perfluorocarboxylic acids in biota, it is proposed that long-chain (C9-C20) perfluorocarboxylic acids, their salts and their precursors are entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity.

It is proposed to conclude that long-chain (C9-C20) perfluorocarboxylic acids, their salts, and their precursors meet one or more of the criteria in section 64 of the Canadian Environmental Protection Act, 1999.

The presence of long-chain (C9-C20) perfluorocarboxylic acids and their salts results from human activity. In addition, long-chain (C9-C20) perfluorocarboxylic acids and their salts meet the criteria for persistence as set out in the Persistence and Bioaccumulation Regulations. While there is scientific evidence that long-chain (C9-C20) perfluorocarboxylic acids and their salts can accumulate and biomagnify in terrestrial and marine mammals, only C11, C12 and C14 perfluorocarboxylic acids and their salts meet the criteria for bioaccumulation as defined in the Persistence and Bioaccumulation Regulations.

Where relevant, research and monitoring will support verification of assumptions used during the screening assessment and, where appropriate, the performance of potential control measures identified during the risk management phase.