Supplementary data

Dietary exposure to perfluoroalkyl acids for the Swedish population in 1999, 2005 and 2010

Robin Vestergren†*, Urs Berger†, Anders Glynn‡ and Ian T. Cousins†

† Department of Applied Environmental Science (ITM), Stockholm University, SE-106 91 Stockholm, Sweden.

‡ Swedish National Food Administration, Research and Development Department, P.O. Box 622, SE-751 26, Sweden.

* Corresponding author email: .

Chemicals and standards

All native and stable isotope labeled PFAAs were provided by Wellington Laboratories in 50 µg mL-1 solutions or in 2 µg mL-1 mixture solutions. The 11 target analytes were perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS). Internal standards were13C2-PFHxA, 13C4-PFOA, 13C5-PFNA, 13C2-PFDA, 13C2-PFUnDA, 13C2-PFDoDA, 18O2-PFHxS and 13C4-PFOS. 13C8-PFOA and 13C8-PFOS were used as volumetric standards in the calculation of the internal standard recoveries. All isotope labeled standards were certified to contain <0.5% of their native analogues.

All chemicals were analytical reagent grade. Tetra butyl ammonium hydrogen sulfate (TBA) (MERCK), sodium hydroxide (Akzo Nobel) sodium carbonate (Riedel de Haen), sodium hydrogen carbonate (KEBO), ammonium acetate (KEBO) and anhydrous granulated sodium sulfate (Scharlau) were used. Florisil sorbent (60/100 mesh) and Supelclean graphitized carbon (ENVI-carb) were purchased from SUPELCO. The water used in the method was HPLC grade (PROLABO Chromanorm) and was passed through a mixed mode C8 plus quaternary amine (CUQAX) solid phase extraction (SPE) cartridge supplied by UCT to remove any residual PFAAs. Methyl tert-butyl ether (MTBE) (Rathburn chemicals) was passed through a column packed with Florisil sorbent to remove any residual PFCAs and PFSAs. Methanol (LiChrosolv grade) was supplied by MERCK and used without further purification. All laboratory disposables (polypropylene or glass) were rinsed with methanol before usage.

Analytical method

Quantitative analysis of the 11 target analytes was performed using a recently developed method that had been optimized to achieve low method detection limits in a wide range of food matrices. A detailed description of this method is given elsewhere (Vestergren et al., 2012). In brief, 200 pg of isotope labeled internal standards were spiked to 2-10 g wet weight of food sample in a 50 mL polypropylene tube and left to equilibrate with the food material overnight. Prior to extraction, the food samples were vortex mixed with 1.5 mL of aqueous NaOH (400 mM) and left to soak for 30 min to allow release of aged PFCA and PFSA residues. Extraction was carried out by ion-pair extraction into 5 mL of MTBE using TBA reagent and basic pH buffer solution. The extraction was repeated twice and the MTBE fractions were combined in a 15mL tube and evaporated to a final volume of approximately 3 mL under a gentle stream of dry nitrogen gas. Solid phase extraction (SPE) was performed using a hand-packed cartridge filled with Florisil (1.5 g) sorbent mixed with ENVI-carb (25 mg). Prior to loading the sample the SPE cartridge was washed with 5 mL of MeOH and conditioned with 5 mL of MTBE. After applying the sample the cartridge was washed with 10 mL of MTBE (discarded) and the target compounds were eluted with 6 mL of a 30/70 MeOH/MTBE mixture (vol/vol). The purified extract was evaporated to ~100 µL and the final volume was adjusted to ~250 µL by addition of volumetric standard (100 pg total spike) and 100 µL aqueous ammonium acetate (4 mM). The extracts were frozen and centrifuged before an aliquot of the clear supernatant was transferred to an LC auto injector vial for instrumental analysis.

Table S1. Description of food groups and weight of the homogenate as consumed by the average Swedish population.

Food group / 1% of annual average consumption (g) / Description
1999 / 2005 / 2010
Dairy products / 1685 / 1758 / 1557 / Milk, sour milk, yogurt, cream, hard cheese, processed cheese, cottage cheese
Meat products / 567 / 744 / 759 / Beef, pork, lamb, poultry, cured/processed meats, sausages
Fats / 175 / 140 / 135 / Butter, margarine, cooking oil, mayonnaise,
Pastries / 137 / 191 / 185 / Biscuits, buns, cakes
Fish products / 133 / 167 / 172 / Fresh and frozen fillets of fish, canned fish products, shellfish
Egg / 92 / 81 / 84 / Hen eggs
Cereal products / 694 / 911 / 844 / Flour, grain, corn flakes, pasta, bread including whole meal bread
Vegetables, including root vegetables / 548 / 636 / 704 / fresh and frozen vegetables, canned vegetable products
Fruit / 641 / 683 / 867 / Fresh and frozen fruit, canned fruit products
Potatoes / 514 / 443 / 458 / Fresh potatoes, French-fries, crisps
Sugar and sweets / 286 / 318 / 453 / Sugar, chocolate, sugar sweets, sauces (e. g. ketchup)
Soft drinks, lemonade / 1188 / 1267 / 1205 / Soft drinks, mineral water, light lager, medium-strong beer

Table S2. Method detection limit (MDL) and method limit of quantification (MLQ) in pg g-1 wet weight for PFCAs and PFSAs in the different food matrices.

PFHxA / PFHpA / PFOA / PFNA / PFDA / PFUnDA / PFDoDA / PFTrDA / PFTeDA / PFHxS / PFOS
Dairy products
MDL / 4.5 / 2.7 / 6.2 / 3.4 / 4.1 / 2.7 / 2.7 / 2.7 / 2.7 / 2.7 / 3.0
MLQ / 9.1 / 8.0 / 9.6 / 8.5 / 8.5 / 8.1 / 8.0 / 8.0 / 8.0 / 8.0 / 8.0
Meat products
MDL / 3.3 / 1.9 / 4.5 / 2.5 / 3.0 / 2.0 / 1.9 / 1.9 / 1.9 / 1.9 / 2.2
MLQ / 6.6 / 5.8 / 7.0 / 6.2 / 6.2 / 5.9 / 5.8 / 5.8 / 5.8 / 5.8 / 5.9
Fats
MDL / 3.9 / 2.3 / 5.4 / 3.0 / 3.6 / 2.4 / 2.3 / 2.3 / 2.3 / 2.3 / 2.6
MLQ / 8.0 / 7.0 / 8.4 / 7.4 / 7.5 / 7.1 / 7.0 / 7.0 / 7.0 / 7.0 / 7.0
Pastries
MDL / 1.7 / 1.0 / 2.3 / 1.3 / 1.5 / 1.0 / 1.0 / 1.0 / 1.0 / 1.0 / 1.1
MLQ / 3.4 / 3.0 / 3.6 / 3.1 / 3.2 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0
Fish products
MDL / 3.3 / 2.0 / 4.6 / 2.5 / 3.1 / 2.0 / 2.0 / 2.0 / 2.0 / 2.0 / 2.2
MLQ / 6.7 / 5.9 / 7.1 / 6.3 / 6.3 / 6.0 / 5.9 / 5.9 / 5.9 / 5.9 / 5.9
Egg
MDL / 3.3 / 1.9 / 4.5 / 2.5 / 3.0 / 2.0 / 1.9 / 1.9 / 1.9 / 1.9 / 2.2
MLQ / 6.6 / 5.8 / 7.0 / 6.2 / 6.2 / 5.9 / 5.8 / 5.8 / 5.8 / 5.8 / 5.8
Cereal products
MDL / 3.3 / 2.0 / 4.6 / 2.6 / 3.1 / 2.0 / 2.0 / 2.0 / 2.0 / 2.0 / 2.2
MLQ / 6.7 / 5.9 / 7.1 / 6.3 / 6.3 / 6.0 / 5.9 / 5.9 / 5.9 / 5.9 / 6.0
Vegetables. including root vegetables
MDL / 1.7 / 1.0 / 2.3 / 1.3 / 1.5 / 1.0 / 1.0 / 1.0 / 1.0 / 1.0 / 1.1
MLQ / 3.4 / 2.9 / 3.6 / 3.1 / 3.2 / 3.0 / 2.9 / 2.9 / 2.9 / 2.9 / 3.0
Fruit
MDL / 1.7 / 1.0 / 2.3 / 1.3 / 1.6 / 1.0 / 1.0 / 1.0 / 1.0 / 1.0 / 1.1
MLQ / 3.4 / 3.0 / 3.6 / 3.2 / 3.2 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0
Potatoes
MDL / 1.7 / 1.0 / 2.3 / 1.3 / 1.5 / 1.0 / 1.0 / 1.0 / 1.0 / 1.0 / 1.1
MLQ / 3.4 / 3.0 / 3.6 / 3.2 / 3.2 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0
Sugar and sweets
MDL / 1.7 / 1.0 / 2.3 / 1.3 / 1.5 / 1.0 / 1.0 / 1.0 / 1.0 / 1.0 / 1.1
MLQ / 3.4 / 3.0 / 3.6 / 3.1 / 3.2 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0 / 3.0
Soft drinks. lemonade
MDL / 0.8 / 0.5 / 1.2 / 0.6 / 0.8 / 0.5 / 0.5 / 0.5 / 0.5 / 0.5 / 0.6
MLQ / 1.7 / 1.5 / 1.8 / 1.6 / 1.6 / 1.5 / 1.5 / 1.5 / 1.5 / 1.5 / 1.5

Table S3. Total method recoveries (%) for the internal standards spiked to the food matrices expressed as a mean of three replicates.

Mean method recovery (%)
13C2-PFHxA / 13C4-PFOA / 13C5-PFNA / 13C2-PFDA / 13C2-PFUnDA / 13C2-PFDoDA / 18O2-PFHxS / 13C4-PFOS
Dairy products
64 / 59 / 52 / 66 / 61 / 50 / 67 / 69
Meat products
64 / 62 / 63 / 62 / 67 / 76 / 67 / 70
Fats
62 / 65 / 69 / 80 / 86 / 91 / 79 / 84
Pastries
59 / 57 / 58 / 55 / 70 / 75 / 71 / 72
Fish products
71 / 59 / 51 / 52 / 57 / 49 / 81 / 69
Egg
89 / 78 / 75 / 74 / 62 / 72 / 90 / 86
Cereal products
56 / 48 / 49 / 54 / 49 / 52 / 58 / 60
Vegetables and root vegetables
73 / 72 / 73 / 70 / 70 / 78 / 77 / 74
Fruit
65 / 73 / 71 / 49 / 71 / 61 / 77 / 66
Potatoes
63 / 56 / 52 / 53 / 48 / 63 / 64 / 55
Sugar and sweets
80 / 84 / 85 / 63 / 116 / 114 / 102 / 104
Soft drinks, lemonade
95 / 52 / 68 / 93 / 98 / 104 / 54 / 96

Figure S1. Average body weight normalized dietary exposure (pg kg-1 day-1) to PFCAs and PFSAs in 1999, 2005 and 2010 in the upper bound exposure scenario.

Figure S2. Contribution of various food groups to the total exposure of PFCAs and PFSAs in the lower bound scenario in 1999.

Figure S3. Contribution of various food groups to the total exposure of PFCAs and PFSAs in the lower bound scenario in 2005.

Figure S4. Contribution of various food groups to the total exposure of PFCAs and PFSAs in the upper bound scenario in 1999.

Figure S5. Contribution of various food groups to the total exposure of PFCAs and PFSAs in the upper bound scenario in 2005.

Figure S6. Contribution of various food groups to the total exposure of PFCAs and PFSAs in the upper bound scenario in 2010.

S2