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Table 4: Summary of the information on alternatives to the use of PFOS

Use

Use status

Alternatives used

Impregnation of textiles, leather and carpets

PFOS-related substances have been phased out in most OECD countries.

Other fluorinated compounds, like C6-fluorotelomers and PFBS, silicone-based products, stearamidomethyl pyridine chloride

Impregnation of paper and cardboard

PFOS-related substances have been phased out in most OECD countries.

Fluorotelomer-based substances and phosphates, mechanical processes

Cleaning agents, waxes and polishes for cars and floors

PFOS-related substances have been phased out in most OECD countries.

Fluorotelomer-based substances, fluorinated polyethers, C4-perfluorinated compounds

Surface coatings, paint and varnish

PFOS-related substances have been phased out in most OECD countries.

Telomer-based compounds, fluorinated polyethers, PFBS, propylated aromatics, silicone surfactants, sulfosuccinates, polypropylene glycol ethers

Oil production and mining

PFOS derivatives may occasionally be used as surfactants in the oil and mining industries.

PFBS, telomer-based fluorosurfactants, perfluoroalkyl-substituted amines, acids, amino acids and thioether acids

Photographic industry

A shift to digital techniques has reduced the use drastically.

Telomer-based surfactant products, hydrocarbon surfactants, silicone products, C3-C4-fluorinated chemicals

Electrical and electronic parts

PFOS-based chemicals are or have been used in the manufacture of digital cameras, mobile phones, printers, scanners, satellite communication, radar systems, etc.

For most of these uses, alternatives are available or are being developed.

Semiconductor industry

PFOS is still used but in lower concentrations.

No substitutes with comparable effectiveness have been identified, and doing so may take up to 5 years, according to the industry. It should be possible to use PFBS, fluorinated polyethers or telomers.

Aviation hydraulic oils

PFOS-related compounds may still be used.

Other fluorinated substances and phosphate compounds could be used.

Pesticides

Sulfluramid is used in some countries as an active substance and surfactant in pesticide products for termites, cockroaches and other insects. Other fluorosurfactants may be used as inert surfactants in other pesticide products.

Synthetic piperonyl compounds such as S Methoprene, Pyriproxyfen, Fipronil and Chlorpyrifos are alternative active substances, sometimes used in combination.

Alternative surfactants may exist.



Medical devices

Old video endoscopes at hospitals contain a CCD colour filter that contains a small amount of PFOS.

PFOS is also used as an effective dispersant for contrast agents in radio-opaque catheters.



Repairing such video endoscopes requires a CCD colour filter containing PFOS. New CCD filters are PFOS-free. For radio-opaque ethylene tetrafluoroethylene, PFBS can replace PFOS.

Metal plating

PFOS-compounds are still used in hard chrome plating.

Cr-III has replaced Cr-VI in decorative chrome plating.



Some non-fluorinated alternatives are marketed but they are not considered equally effective in hard chrome plating. A C6-fluortelomer is used as a substitute and may be effective. PFBS derivatives may also be used. Physical barriers may also be used.

Fire-fighting foams

The use of PFOS-related substances in new products has been phased out in most OECD countries. Stocks are still being used up.

C6– fluorotelomers are used as substitutes in new products; fluorine-free alternatives are used for training exercises and possibly in other settings than offshore.

IV. Properties of alternative substances and hazard assessment

A. Overview



  1. This chapter contains a brief description of the environmental, safety and health properties of PFOS alternatives. For some of these alternatives, a general discussion of properties might be all that is possible owing to a lack of specific information. For each of the chemical groups discussed, a more comprehensive compilation of information would have been possible but was beyond the scope of the present study.

  2. The key to the performance of fluorosurfactants is extremely low surface tension. Currently, no other surfactant can match the low surface tension of PFOS. Because of environmental and health concerns and the often high prices of fluorosurfactants, however, other surfactants should be used as alternatives where very low surface tension levels are not needed.

  3. When production of PFOS ceased in the United States in 2002, other chemicals took their place. They were mainly derivatives of perfluoroalkyl sulfonates with a shorter alkyl chain and C8 based fluorotelomers. Since 2006, the major manufacturers of C8-based telomers have been working towards the elimination of C8-based and longer-chain-based PFCs by 2015, in accordance with the United States Environmental Protection Agency’s 2010/2015 PFOA Stewardship Program.62 Thus, C6 fluorotelomers now dominate the trade. Thus far it has been difficult for non-fluorinated alternatives to gain a firm foothold in the market, partly because of established supplier relationships.

  4. Table 5 gives a brief overview of groups of alternatives to PFOS.

Table 5: Overview of main alternatives to PFOS compounds

Alternative compound

Product trade name

Company

Uses

Perfluorobutane sulfonate (PFBS) derivatives or other alternatives based on various C4-perfluorocompounds

Novec™
Scotchgard™

3M

Paint and coatings industry, electronic coatings, industrial and commercial cleaning, stain protectors for carpets and leather, furniture, automotive uses, hard surfaces and other apparels, catalysts, flame retardants, additives in plastics, industrial coatings, mist suppression, rubber moulding defoamers in electroplating, etc.

Perfluorobutyl methyl ethers

NovecTM

3M

Industrial cleaning

Dodecafluoro-2-methylpentan-3-one

Novec™ 1230

3M

Fire-fighting foams

Polyfluorodialkyl ether sulfonates

FC-53

-

Mist suppressant hard chrome plating

Potassium perfluoroethyl cyclohexyl sulfonate

FC-98

3M

Hydraulic fluids

Fluorotelomer alcohols

and esters



Zonyl®

Capstone®



DuPont

Surfactants, coatings, printing, textile and chemical industries, chrome plating

C6 fluorotelomer sulfonamide compounds

Forafac™ 1157, 1183

DuPont

Fire-fighting foams

Fluorinated co-polymers

Foraperle® 225, etc.

DuPont

Impregnation of leather and indoor car upholstery

CF3 or C2F5 fluoroalkyl polyethers

PolyFox™

OMNOVA Solutions Inc.

Surfactant and wetting additives for coating formulations and floor polish

Propylated naphthalenes

or biphenyls



Ruetasolv™

Rütgers Kureha Solvents

Water-repelling agents for rust protection systems, marine paints, coatings, etc.

Sulfosuccinate


Lutensit™

BASF

Levelling and wetting agents

Edaplan™ LA 451

Münzing Chemie

Paint and coating industry: wetting and dispersing agents for water-based applications such as wood primers

Hydropalat™ 875

Cognis

Siloxanes and silicone polymers

WorléeAdd™

Worlée-Chemie

Wetting agents in the paint and ink industry

AdvantexTM

Bluestar Silicones

Impregnation of all-weather textiles. Also related products for car polish, cleaners, anti-foaming agents, car waxes

Polypropylene glycol ethers

Emulphor™

Enthone


BASF

Cookson Electronics



Levelling and wetting agents

Decorative chrome plating, etc.



B. Shorter-chain perfluoroalkyl sulfonates

  1. After the phase-out of PFOS, 3M introduced a new generation of polymeric anionic fluorinated surfactants (ScotchgardTM and Novec™ products), which are based on perfluorobutane sulfonates (PFBS; C4-chemistry):




  1. These compounds are claimed to have a low dynamic surface tension or rather a rapid surface migration, which is important in high-speed coating processes and low-viscosity systems. Generally these surfactants have a lower surface tension than hydrocarbon and silicone surfactants. They can also be used in smaller amounts than hydrocarbon surfactants. The compounds are said to influence the adhesion of the second-layer coating less than silicon or conventional fluorinated surfactants.

  2. These short-chain alternatives should be useful as surfactants in the paint and coatings industry; for stain-repellent impregnation of textiles, leather and carpets; in electronic coating; in industrial commercial cleaning; and in cleaners for solder flux residue.

  3. According to information from the 2006 OECD survey, 50–160 tonnes of potassium perfluorobutane sulfonate and 40–60 tonnes of perfluorobutane sulfonyl fluoride were produced in 2005 as intermediates for the production of catalysts, flame retardants, additives in plastics, industrial coatings, mist suppression systems, rubber molding defoamers for electroplating and the like.

Health effects of shorter-chain perfluoroalkyl sulfonates

  1. No information is available about the specific chemicals in use; only information about PFBS and its potassium salt (PFBSK) from unpublished laboratory test reports is available. In the Australian assessment those reports are reviewed and evaluated. The following is based on that review.

  2. The body half-life of PFBSK in intravenously exposed monkeys is 4 days. No degradation was detected and urinary excretion of the chemical by the monkeys was a major route of elimination. High levels of binding of perfluorobutane sulfonate to human albumin occurred in the blood. The acute toxicity was low; in rats the oral and skin LD 50 (doses that killed 50%) were more than 2,000 milligrams per kilogram of body weight. The test material was irritating to the eyes and fulfilled the criteria for classification as irritating to eyes (R36). The chemical did not, however, cause skin irritation or sensitization. In oral rat studies NOAEL (no observed adverse effects level) values of 100–300 milligrams per kilogram of body weight per day were detected. The test material was not mutagenic in the applied bacteria tests.

  3. It has been claimed that PFBS does not have the particularly serious toxic effects associated with PFOS and other long-chain analogues but data published in peer-reviewed literature are lacking.

Environmental effects of shorter-chain perfluoroalkyl sulfonates

  1. PFBS is a strongly acidic and highly water-soluble substance which has a low vapour pressure and is poorly adsorbed to soils and sediments, and is therefore expected to remain in the water compartment on release into the environment. PFBS is as persistent in the environment as other perfluorinated compounds and is being detected in increasing concentrations in some water bodies, including the North Sea; bioaccumulation in wildlife and humans, however, seems to be much lower than for PFOS. PFBS stays mostly in the water column as its water solubility is much higher than that of higher homologues. In a laboratory fish test the bioaccumulation potential for PFBS was low.

  2. The Australian report mentioned earlier concludes that as use of PFBS – for example, as a substitute for PFOS – increases, levels of PFBS may build up and be distributed widely in the environment, given that its precursors are likely to be more volatile, yet structurally very similar, to PFOS.

  3. A range of unpublished tests show that PFBS has low toxicity for birds, algae, aquatic invertebrates, fishes or sewage micro-organisms. In a quail reproduction study the dietary NOAEC (no observed adverse effects concentration) was 900 milligrams of PFBS per kilogram of wet weight feed.63 However, PFBS was not tested in the chironomid Chironomus tentans, which has been shown to be two to three orders of magnitude more sensitive to the effects of PFOS than other aquatic organisms. Whether Chironomus tentans would be similarly sensitive to PFBS is unclear.

C. Shorter-chain perfluoroalkyl ketones and ethers

  1. According to 3M’s website, a C6-fluorinated compound, Novec 1230, is used in a fire protection fluid produced by that company. The compound is dodecafluoro-2-methylpentan-3-one (CAS no. 756-13-8):

Dodecafluoro-2-methylpentan-3-one



  1. 3M also markets some C4-perfluorinated compounds for commercial and industrial cleaning under the trademark Novec, such as methyl nonafluorobutyl ether (CAS no. 163702-07-6) and methyl nonafluoroisobutyl ether (CAS no. 163702-08-7). Here the methyl group is not fluorinated.

Methyl nonafluorobutyl ether



Health effects of shorter-chain perfluoroalkyl ketones and ethers

  1. Published peer-reviewed data are lacking.

Environmental effects of shorter-chain perfluoroalkyl ketones and ethers

  1. Published peer-reviewed data are lacking.

D. Polyfluorodialkyl ether sulfonates

  1. In China FC-53 (potassium 1,1,2,2-tetrafluoro-2-(perfluorohexyloxy)ethane sulfonate) and FC 53B (potassium 2-(6-chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyloxy)-1,1,2,2-tetrafluoroethane sulfonate) are available as PFOS alternatives for chrome plating.64 The structure formulas of FC-53 and FC-53B are, respectively:





Health effects of polyfluorodialkyl ether sulfonates

  1. No data are available.

Environmental effects of polyfluorodialkyl ether sulfonates

  1. No data exist other than Chinese QSAR model results for persistence (half-lives) in water, sediment, soil and air, bioconcentration factors (BCFs) and toxicity to fish showing less hazardous potential than PFOS.

E. Fluorotelomers and fluorophosphates

  1. In general, fluorotelomers have been the most common alternatives to PFOS compounds. They are not fully fluorinated but contain more reactive hydrocarbon parts and functional groups. The perfluorinated tail, however, is similar to the tail of PFOS and is as persistent, and these chemicals are precursors of perfluorinated carboxylic acids (PFCAs). According to information from the 2006 OECD survey, more than 5,000 tonnes of PFCA precursors were produced and used in 2005.

  2. One of the basic structures is 8:2 fluorotelomer alcohol (8:2 FTOH), also named 1H,1H,2H,2H-perfluorodecanol; it has a C8-perfluorinated tail:



  1. DuPont specializes in fluorotelomers and markets a wide range of Zonyl® products, generally associated with 8-2 alcohol-based products, and CapstoneTM products, generally associated with 6:2 fluorotelomer-based products.

  2. An acrylate of fluorotelomer with the name of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl acrylate (CAS no. 27905-45-9) has been marketed by DuPont as a telomer intermediate under the trade name of Zonyl® TA-N:



  1. These fluorotelomers are covered by the United States Environmental Protection Agency’s 2015 phase out. While the shorter- and longer-chain telomers are not subject to the phase out, they are covered by the recent United States Environmental Protection Agency action plan for long-chain PFCs.65

  2. DuPont manufactures a range of fluorotelomers called DuPontTM Forafac products, with 65–95% C6-fluorinated amphoteric telomers based on perfluorohexyl ethyl sulfonamide, which are used in fire-fighting foam formulations .66 A possible structure formula for an amphoteric compound 1H, 1H, 2H, 2H-perfluorooctane sulfonamidopropyl carboxybetaine, which now replaces the analogous fully fluorinated perfluorooctane compound, is:



  1. The polyfluoroalkyl phosphonic acids and phosphoric acids and their diesters (PAPs and diPAPs), used mainly in food packaging, have recently been discovered in the environment and in people.67 Here are examples of structure formulas:

Perfluorooctyl phosphonate 8:2 PAP



8:2 diPAP



  1. DuPont markets more Zonyl products in this group, such as Zonyl® 9027, a spot and dirt repellent, which is a telomer B phosphate diethanolamine (CAS no. 65530-63-4). Again, these chemicals are based on C8-fluorine chemistry and are to be phased out based on a global agreement with most producing companies by December 31, 2015. Similar chemicals with shorter chain lengths may still be used.

  2. The C8-telomer-based materials are disappearing in favour of C6-based materials. C6 based materials are inherently more expensive (by a substantial amount) than C8- or telomer-based materials.68

Health effects of fluorotelomers and fluorophosphates

  1. There is a lack of health data for the many specific and complex chemicals fluorotelemers and fluorophosphates used in practice. Some data exist on adverse effects seen in experimental animals and laboratory tests of precursors and the final degradation products: perfluorocarboxylic acids/salts (PFCAs) such as perfluorooctanoate (PFOA). Some PFCAs have well-known adverse health impacts. For example, PFOA has been shown to be tumorigenic and immunotoxic in laboratory animals. Little toxicological or ecotoxicological information is available for the other PFCAs, however, although they have been regularly detected in human blood, umbilical cord blood and breast milk. The toxicity of the degradation products increases with fluorinated chain length.

Environmental effects of fluorotelomers and fluorophosphates

  1. There is also a lack of environmental data on the fluorotelemers and fluorophosphates used in practice. Some are volatile and may undergo long-range air transportation. They degrade to perfluorinated carboxylic acids, such as perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), in organisms and in nature. These perfluorinated acids have been widely detected in the environment and wildlife. The environmental hazard, including tendency to bioaccumulation, increases with chain length, and all perfluorinated alkyl chains are completely persistent in nature.

F. Fluorinated co-polymers

  1. DuPont markets many Zonyl® co-polymers for various purposes, such as Zonyl® G Fabric Protector for textiles, which consists of 2-methyl-2-propenoic acid dodecyl ester polymer with 10 15% -fluoro--[2-[(2-methyl-1-oxo-2-propenyl)oxy]ethyl poly(difluoromethylene) (CAS no. 65605 58 5).

  2. Foraperle® 225 (DuPont) is an acrylic fluorinated co-polymer (25%) in a solvent medium (75% butyl acetate) used for finishing and protection of leathers and car upholstery through water and oil repellence. It contains the compound 2-propenoic acid, 2-methyl-, hexadecyl ester (hexadecyl methacrylate), polymers with 2-hydroxyethyl methacrylate, --perfluoro-C10-C16-alkyl acrylate and stearyl methacrylate (CAS no. 203743-03-7). Another acrylic fluorinated co-polymer is dodecyl methacrylate polymer with α-fluoro--[2-[(1-oxooctadecyl)oxy]ethyl]-poly(difluoromethylene) (CAS no. 65530-65-6), which is used in a concentration of 0.085–0.45%.

  3. The substance 2-propenoic acid, 2-methyl-, hexadecyl ester (hexadecyl methacrylate), polymers with 2-hydroxyethyl methacrylate, ---perfluoro-C10-C16-alkyl acrylate and stearyl methacrylate (CAS no. 203743-03-7) has been prohibited for manufacture, use, import, sale or offer for sale in Canada as it is a precursor to long-chain PFCAs. The following substances are also prohibited:

  • Hexane,1,6-diisocyanato-, homopolymer, reaction products with α-fluoro-ω-2-hydroxyethyl-poly(difluoromethylene), C16-20-branched alcohols and 1-octadecanol

  • 2-propenoic acid, 2-methyl-, 2-methylpropyl ester, polymer with butyl 2-propenoate and 2,5 furandione, γ-ω-perfluoro-C8-14-alkyl esters, tert-Butyl benzenecarboperoxoate-initiated

  • 2-propen-1-ol, reaction products with pentafluoroiodoethane tetrafluoroethylene telomer, dehydroiodinated, reaction products with epichlorohydrin and triethylene tetramine.

  1. In most instances the exact composition of the products and their active substances are trade secrets and have not been disclosed by the suppliers.
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