IFE Foam Conference: Foam Under Fire!

Transcription

1 DuPont Fluorotelomer AFFF Update Presented at IFE Foam Conference: Foam Under Fire! 20 December 2004 Manchester, UK Dr. Stephen Korzeniowski

2 Presentation Agenda Function of Fluorosurfactants in AFFF Telomer Chemistry AFFF Beliefs - Fact or Fiction AFFF Surfactant Toxicology Degradation Studies Discussion

3 Why are we using Fluorotelomer Surfactants in FFF? SHK 20 Dec 2004 Fluorotelomer Surfactants (FT) in AFFF have a proven trackrecord of superior performance on Class B fires Lower Critical Application Rate Faster Knockdown Superior Burnback Resistance Provide significantly higher level of fire suppression capability than any other foam agent currently available Responsible for saving numerous lives and billions of dollars worth of plant and equipment over the past 35 years

4 Why are we using Fluorotelomer Surfactants in FFF? FT enable water to float onto the hydrocarbon s surface Vapors emission is stopped FT help make the foam oil (hydrocarbon) repellent Foam can be used on direct application and remain efficient FT limits the foam contamination The foam blanket gives the best resistance to burn back and re-ignition Technologies other than FT have important limitations: Lower efficiency on direct application Lower burn back resistance Require a higher application rate SHK 20 Dec 2004

5 Different Process and Chemistry SHK 20 Dec 2004 Telomerization vs. ECF Products Telomerization (Fluorotelomers) CF 2 =CF 2 (TFE) ECF (ElectroChemical Fluorination, 3M) C C 8 H 17 SH 7 H 15 CO 2 H F(CF 2 CF 2 ) n I (Telomer A) n = 2-8 n = 4 [O] C 7 F 15 CO 2 H (PFOA) F(CF 2 CF 2 ) n CH 2 CH 2 I (Telomer B) C 8 H 17 SO 2 Cl C 8 F 17 SO 2 F (POSF) C 7 F 15 COF [HF, e - ] C 7 F 15 CO 2 H (PFOA*) C 8 F 17 SO 3 X (PFOS*) C 8 F 17 SO 2 N(C 2 H 5 )CH 2 CH 2 OH 30% Branched Alkyl (N-EtFOSE) F(CF 2 CF 2 ) n CH 2 CH 2 OH (Telomer BA) Straight Chain Alkyl Sales Products (proposed degradation path ) Sales Products Linear Branched PFBS-Based C 4 F 9 SO 2 N(C 2 H 5 )CH 2 CH 2 OH Fingerprint: Linear vs. Branched *Note : ECF produced materials are approximately 30% branched at the fluorinated chain end and contain, 5,6,7,8 and 9 carbon chain length material

6 AFFF Beliefs: Sources Belief: Fluototelomer-based AFFF fluorosurfactants are a primary source of PFCAs, perfluorocarboxylic acids, in the environment True or False False There are many potential major and direct sources of PFCAs in the environment. In any discussion the larger picture needs to be considered

7 Potential PFCA Sources : F(CF 2 ) n COO - SHK 20 Dec s - present Direct Sources Fluoropolymer Manufacture F(CF 2 ) 7 COO - NH4 + Fluoropolymer Dispersions F(CF 2 ) n COO - NH4 + Fluoropolymer Manufacture F(CF 2 ) n COO - NH4 + n = 6-12 Consumer Products and Sales of APFO APFO Manufacture 1950 s - present PFCA s in the Environment ECF AFFF Agents PFCA-based 1960 s-70 s Indirect Sources AFFF Agents C-6 Telomer-based 1970 s - present Telomer Manufacture, Industrial & Consumer Use Potential Degradation 1970 s - present APFN Manufacture 1960 s - present AFFF agents PFOS-based 1970 s - present PFCA Impurities in POSF Materials 1950 s - present POSF Materials - Potential Breakdown to PFCA s 1950 s - present SHK 20 Dec 2004

8 AFFF Beliefs: Manufacture Belief: AFFF fluorosurfactants are primarily made from the Telomer alcohols such as F(CF 2 CF 2 ) n CH 2 CH 2 OH True or False False Most AFFF fluorosurfactant agents are actually made from Telomer B Iodide F(CF 2 CF 2 ) n CH 2 CH 2 I not the alcohols

9 AFFF Beliefs: Manufacture Belief: AFFF fluorosurfactants are made largely from eight (8) fluorinated carbons such as F(CF 2 ) 8 CH 2 CH 2 I True or False False Most AFFF fluorosurfactant agents are actually made mostly from six (6)( ) fluorinated carbons such as F(CF 2 ) 6 CH 2 CH 2 I This was clearly shown by the work of Dr. Jennifer Field, Oregon State University

10 Telomer-based AFFF Surfactants Telomer-based AFFF agents contain predominantly C 6 fluorinated surfactants as the key active ingredient that contributes to film formation verified with direct manufacturers Telomer-based AFFF agents are not made with and do not contain or degrade into PFOS Telomer-based AFFF agents are not made with PFOA and no PFOA-based products are added

11 AFFF Beliefs: Manufacture Belief: AFFF fluorosurfactant manufacturers changed their manufacturing practices as a result of the EPA ECA actions and changed their products from 8 carbons to six over the past 5 years F(CF 2 ) 8 CH 2 CH 2 X F(CF 2 ) 6 CH 2 CH 2 X True or False False F(CF 2 ) 8 CH 2 CH 2 X Most AFFF fluorosurfactant agents are actually made from largely six (6)( ) fluorinated carbon backbones and have been for decades F(CF 2 ) 6 CH 2 CH 2 X

12 J. Field Report Findings SHK 20 Dec 2004 Composition of Telomer Sulfonates Tyndall Wurtsmith (500m) % :2 % : :2 40 8: :2 FtS 6:2 FtS 8:2 FtS :2 FtS 6:2 FtS 8:2 FtS 2.6 Wurtsmith (20m) % :2 8: :2 FtS 6:2 FtS 8:2 FtS The report confirms that telomer-based AFFF agents are predominantly C 6 -based These sulfonates were not found at Fallon!! Examples: 6:2 FtS = C 6 F 13 CH 2 CH 2 SO - 3

13 AFFF Beliefs: Surfactant Breakdown SHK 20 Dec 2004 Belief: AFFF fluorosurfactants are known to breakdown into perfluorocarboxylic acids like PFOA since these acids are sometimes found where AFFF agents were previously used True or False False There is no known evidence that the Fluorotelomer based sulfonate-type surfactants, such as those found by Dr. Field in the Air Force base studies, degrade in the environment to PFOA or related acids No correlation appears to exist between the occurrence and concentration of telomer sulfonates and perfluoroalkyl carboxylates in the groundwater sample set

14 J. Field Report Findings SHK 20 Dec 2004 Composition of Perfluoroalkyl Sulfonates Fallon Wurtsmith (20m) % C4 C5 C6 PFBS PFPS PFHxS PFHpS PFOS C8 % C C8 0 PFHxS PFOS Tyndall Wurtsmith (500m) % C4 C5 PFBS PFPS PFHxS PFHpS PFOS C6 C8 Example: PFOS = C 8 F 17 SO % C6 PFHxS 30.6 C8 PFOS ECF-based Agents contained a range of chain lengths

15 J. Field Report Findings SHK 20 Dec 2004 Composition of Perfluoroalkyl Carboxylates (PFCAs) Fallon Wurtsmith (20m) % C Tyndall C C8 PFHxA PFHpA PFOA No Telomer sulfonates found here % C6 C PFHxA PFHpA PFOA Wurtsmith (500m) % C C7 C8 PFHxA PFHpA PFOA % C8 C6 0 0 PFHxA PFHpA PFOA Example: PFOA = C 7 F 15 COO - Note: likely source of PFCAs - as an additive to or as a contaminant in the POSF-based foam surfactants

16 General Conclusions SHK 20 Dec 2004 Telomer fluorosurfactants in AFFF sold to the military: Precursor - C 6 F 13 CH 2 CH 2 SX from C 6 F 13 CH 2 CH 2 I Type of telomer surfactants - contain group C 6 F 13 CH 2 CH 2 SCH 2 CH~ Degradation product found in groundwater - C 6 F 13 CH 2 CH 2 SO - 3 6:2 telomer sulfonate C 6 F 13 CH 2 CH 2 SX --> C 6 F 13 CH 2 CH 2 SCH 2 CH~ --> C 6 F 13 CH 2 CH 2 SO 3-6:2 Telomer sulfonate is the likely biodegradation product of the C 6 telomer fluorosurfactants contained in milspec AFFF Additional laboratory studies underway

17 AFFF Beliefs: Surfactants as Pollutants Belief: AFFF fluorosurfactants are an extreme pollutant ; IFJ, Sept 2004 True or False False It is known these surfactants and likely degradation products are persistent in the environment Persistence alone does not make them extreme pollutants; it does make them persistent compounds and reinforces need to use these products judiciously Hazard or toxicology needs to be considered in any comprehensive risk assessment

18 AFFF Beliefs: Surfactants as Hazardous Chemicals Belief: AFFF and other related fluorotelomers are generally hazardous chemicals and suspect genotoxins True or False False In general, AFFF and related fluorotelomer products are not genotoxins i.e. not mutagenetic materials In general, AFFF and related fluorotelomer products are not viewed as significant environmental toxins

19 Fluorotelomer Genotoxicity SHK 20 Dec 2004 Telomer Product Examples Acrylic Polymers for textiles 2 products Urethane Polymer for carpets Acrylic Polymer for Stone & Tile Forafac 1157 AFFF Fluorosurfactant Ethoxylate Fluorosurfactant Genetic Test In vitro mammalian chromosome aberration test Salmonella typhimurium reverse mutation assay In vitro mammalian chromosome aberration test Salmonella typhimurium reverse mutation assay Reverse mutation assay with S. typhimurium and E. coli Reverse mutation assay with S. typhimurium and E. coli and Chromosomal abberation test with Chinese Hamster cells Reverse mutation assay with S. typhimurium and E. coli Result Negative Negative Negative Negative Negative Phosphate Fluorosurfactant In vitro mammalian chromosome aberration test Salmonella typhimurium reverse mutation assay Negative Conclusion: As a class of compounds the fluorotelomers are neither genotoxic nor mutagenetic

20 Forafac 1157 Surfactant Toxicity SHK 20 Dec 2004 Test Description Results Comment 28-day Subchronic Oral Toxicity in Rats Developmental Toxicity Bioconcentration in Carp, Cyprinus carpio, via OECD 305 NOEL for M/F rats is 200 mg/kg/day; NOAEL for F rats was 1000 mg/kg/day PILOT: Reduced maternal weight, no fetal effects For main active ingredient >97.5% of substance: At 5 ug/l, BCF = < 5.1 At 50 ug/l, BCF = < 51 Doses were 0, 10, 40, 200, and 1000 mg/kg/day. No mortality seen; no effects on hematology and in urinary tests Main study in progress: 0, 25, 150, 1000 mg/kg/day Whole fish test Forafac 1157 backbone is F(CF 2 CF 2 ) n CH 2 CH 2 SO 2 Y, where n = 3 predominantly, and Y are various organic functional groups or appendages

21 Forafac 1157 Surfactant Ecotoxicity Test Description Results Comment Acute fish toxicity with killifish, Oryzias latipes Invertebrates toxicity with Daphnia magna Bacterial toxicity with Pseudomonas putida 96-hour LC 50 > 35mg/L 24-hour EC 50 = g/l 16-hour EC 50 = mg/l No greater than lowmoderate toxicity Low toxicity Low-moderate toxicity Forafac 1157 backbone is F(CF 2 CF 2 ) n CH 2 CH 2 SO 2 Y, where n = 3 predominantly, and Y are various organic functional groups or appendages

22 Zonyl Sulfonates Toxicity Examples Test Description For Zonyl FS-62 Developmental Toxicity in Rats via Inhalation 28-day Subchronic Oral Toxicity in Rats Results NOEL for rats is 25 ppm NOEL for M/F rats is 15 mg/kg/day Acute Toxicity in Rats ALD = 2300 mg/kg in male rats Comment Inhalation concentrations were 0, 25, 125, and 600 ppm. No fetal resorptions or external malformations at any dose Doses up to 150 mg/kg/day. No mortality seen; target: kidney Considered slightly toxic; doses up to 3400 mg/kg Zonyl FS-62 is largely F(CF 2 CF 2 ) n CH 2 CH 2 SO 3 X, where n = 3, and X is a counterion

23 Zonyl Sulfonates Ecotoxicity Examples Test Description for Zonyl FS-62 Acute fish toxicity with fathead minnow, Pimephales promelas Acute fish toxicity with rainbow trout, Oncorhychus mykiss Invertebrates toxicity with Daphnia magna Green Algae toxicity with Seleanstrum capricornutum Results 96-hour LC 50 = 316mg/L 96-hour LC 50 > 94.1 mg/l 48-hour EC 50 > 85.9 mg/l 72-hour E b C 50 and E r C 50 > 199 mg/l Comment Slight toxicity Slight toxicity Slight toxicity Slight toxicity Zonyl FS-62 is largely F(CF 2 CF 2 ) n CH 2 CH 2 SO 3 X, where n = 3, and X is a counterion

24 DuPont Telomer-based Surfactants & Polymers Biodegradation Studies Respiration Inhibition Test Studies Underway Ready Biodegradation Screening Studies Ethoxylate and Phosphate Surfactants (OECD 301B/D, 28 days) Screening Studies Forafac 1157 Surfactants (OECD 301B/D, 28 days) Ready Biodegradation Screening Studies Acrylate and Urethane polymers (OECD 301B/D, 28 days) Yes Assess Ready Biodegradability No No further Test Needed Soil and Sediment Studies OECD 307 and months Modified Inherent Biodegradation (Modified OECD 302B; days)

25 Presentation Conclusions The importance of understanding the facts around Telomer chemistry origins and fate cannot be overemphasized what to believe or not to believe The AFFF surfactants as described here are not judged as substantial toxicological hazards, albeit they are persistent The J. Field study provides no evidence that telomer sulfonates break down in the environment into PFOA or other perfluoroalkyl carboxylates additional definitive degradation studies are underway The report confirms that telomer-based AFFF agents are largely C 6 - based predominant manufacture is via the Telomer iodides

26 Discussion and Questions