Supplementary material
Biotransfer of perfluoroalkyl acids in dairy cows in a naturally contaminated environment
Robin Vestergren1*, Francis Orata1,2, Urs Berger1, Ian T. Cousins1
1
Department of Applied Environmental Science (ITM), Stockholm University, SE-106 91
Stockholm, Sweden.
2
Pure and Applied Chemistry Department, Masinde Muliro University, Kenya (present
affiliation)
*Corresponding author
Chemicals and reagents
All native and isotope labeled PFCA and PFSA standard compounds were purchased from
Wellington Laboratories (Guelph, ON, Canada) in 2 µg mL-1 solution mixtures. The 9 target
analytes were perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA),
perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA),
perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorohexane
sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS). Internal standards were 13C2PFHxA, 13C4-PFOA, 13C5-PFNA, 13C2-PFDA, 13C2-PFUnDA, 13C2-PFDoDA, 18O2-PFHxS and
13
C4-PFOS. 13C8-PFOA and 13C8-PFOS were used as volumetric standards in the calculation of
total method recovery of the internal standards. All isotope labeled standards were certified to
contain <0.5% of their native analogues.
All reagents were analytical reagent grade. Tetrabutyl ammonium hydrogen sulfate (TBA) was
purchased from MERCK, sodium hydroxide (NaOH) from Akzo Nobel, sodium carbonate
(Na2CO3) from Riedel-de Haën, sodium hydrogen carbonate (NaHCO3) and ammonium acetate
(CH3COONH4) from KEBO, formic acid (CH2O2) from Fluka, potassium hydroxide (KOH) from
BDH, ammonium sulfate ((NH4)2SO4) from Sigma-Aldrich, and anhydrous granulated sodium
sulfate (Na2SO4) from Scharlau. Florisil sorbent (60/100 mesh) and Supelclean graphitized
carbon (ENVI-carb) were obtained from SUPELCO. The water used in the method was HPLC
grade (PROLABO Chromanorm). Acetonitrile (Chromasolv grade) was purchased from Riedelde Haën. Methyl tert-butyl ether (MTBE) was purchased from Rathburn chemicals. Methanol
(MeOH, LiChrosolv grade) was supplied by MERCK.
Table S1. Method detection limits (MDLs) in ng kg-1 or ng L-1for PFAAs in the different intake
media, cow tissues and excretion media.
Sample medium
Intake media
PFOA
PFNA
PFDA
PFUnDA
PFDoDA
PFOS
Water (ng L-1)
Silage (ng kg-1)
Barley (ng kg-1)
Supplements (ng kg-1)
Cow tissues
Liver (ng kg-1)
Blood (ng kg-1)
Muscle (ng kg-1)
Excretion media
Urine (ng L-1)
Feces (ng kg-1)
Milk (ng L-1)
0.071
6.3
6.1
5.8
0.025
1.5
1.8
2.5
0.015
1.8
1.6
3.1
0.014
1.6
1.9
3.1
0.011
1.0
0.5
3.5
0.020
2.0
1.9
2.2
6.6
6.8
5.3
2.3
2.0
1.3
3.0
2.9
1.3
2.6
2.6
0.8
1.0
1.2
0.5
1.7
1.9
1.6
3.3
6.4
3.7
0.9
2.9
1.2
0.7
3.1
1.0
1.3
2.0
1.5
0.5
2.0
0.7
0.8
6.1
3.3
Table S2. Average total method recoveries (%) for the internal standards spiked at approximately
100 ng kg-1 to the different matrices except drinking water where a spike concentration of 1 ng L1
was used.
Sample medium
Intake media
Water
Silage
Barley
Supplements
Cow tissues
Liver
Blood
Muscle
Excretion media
Urine
Feces
Milk
13
C4-PFOA
13
C5-PFNA
13
C2-PFDA
13
C2-PFUnDA
13
C2-PFDoDA
13
C4-PFOS
90
62
61
53
82
53
56
52
65
55
53
50
59
49
52
49
58
51
49
52
73
67
68
65
68
64
80
71
73
75
60
57
58
53
55
60
50
50
53
64
62
78
70
58
78
68
53
72
65
50
71
58
51
68
59
49
63
74
55
80
10
Concentration (ng L-1)
8
6
Individual samples
Pooled sample
4
2
0
PFOA
PFOS
PFNA
PFDA
Figure S1. Measured concentrations of PFAAs in milk samples from 6 individual cows that were
milked by hand (arithmetic mean±1 standard error) and one pooled milk sample taken from the
milk tank.
12
Concentration (ng L-1)
10
8
PFOA
PFOS
6
PFNA
4
PFDA
2
0
Nov
Dec
Jan
Feb
Mar
Apr
Figure S2. Measured concentrations of PFAAs in pooled milk samples over the sampling
campaign November 2010 to April 2011.