Environmental Occurrence of Perfluoroalkyl Acids and Novel

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Environmental occurrence of perfluoroalkyl acids and novel fluorotelomer surfactants in the freshwater fish Catostomus commersonii and sediments following firefighting foam deployment at the Lac-Mégantic railway accident Gabriel Munoz, Mélanie Desrosiers, Sung Vo Duy, Pierre Labadie, Helene Budzinski, Jinxia Liu, and Sébastien Sauvé Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b05432 • Publication Date (Web): 06 Jan 2017 Downloaded from http://pubs.acs.org on January 6, 2017

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Environmental Science & Technology

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Environmental occurrence of perfluoroalkyl acids and novel fluorotelomer

2

surfactants in the freshwater fish Catostomus commersonii and sediments

3

following firefighting foam deployment at the Lac-Mégantic railway accident

4 5

Gabriel Munoza,b, Mélanie Desrosiersc, Sung Vo Duyb, Pierre Labadiea,d, Hélène Budzinskia,d,

6

Jinxia Liue, Sébastien Sauvéb,*

7 8

a

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Libération, F-33400 Talence, France.

: Université de Bordeaux, EPOC, UMR 5805, LPTC Research Group, 351 Cours de la

10

b

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Montréal, QC, Canada, H3C 3J7.

12

c

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développement durable, de l’environnement et de la lutte contre les changements climatiques,

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2700 Einstein Street, Quebec City, QC, Canada, G1P 3W8.

15

d

16

Talence, France.

17

e

18

Canada, H3A 0C3.

: Department of Chemistry, Université de Montréal, C.P. 6128, Succursale Centre-Ville,

: Centre d’expertise en analyse environnementale du Québec (CEAEQ), Ministère du

: CNRS, EPOC, UMR 5805, LPTC Research Group, 351 Cours de la Libération, F-33400

: McGill University, Department of Civil Engineering, 817 Sherbrooke Street West, Montreal, QC,

19 20

*Corresponding Author. Contact: [email protected]

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1 ACS Paragon Plus Environment


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Word Count

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Main text = 6100 w.

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Tables = 2 x 300 w.

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Figures = 2 x 300 w.

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GRAPHICAL ABSTRACT

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30 31 32

ABSTRACT

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On July 6th 2013, an unmanned train laden with almost 8 million liters of crude oil careened off

34

the rails downtown Lac-Mégantic (Québec, Canada). In the aftermath of the derailment accident,

35

the emergency response entailed the deployment of 33,000 L of aqueous film forming foam

36

(AFFF) concentrate that contained proprietary fluorosurfactants. The present study examines the

37

environmental occurrence of perfluoroalkyl acids (PFAAs) and newly-identified per and

38

polyfluoroalkyl substances (PFASs) in the benthic fish white sucker (Catostomus commersonii)

39

and sediments from Lake Mégantic and Chaudière River. In sediments, PFAAs displayed

40

relatively low concentrations (∑PFAAs = 0.06–0.5 ng g-1 dw) while the sum of fluorotelomer-

41

based PFASs was in the range 400 mm), collected

137

in 2011 in Lake Mégantic, were used as a reference prior to the accident. Following the accident,

138

white suckers were collected in Lake Mégantic as well as in the Chaudière River downstream

139

from the AFFF-impacted site, from the Lac-Mégantic dam where the Chaudière River takes its

140

source (kilometric point KP-0) down to KP-92, after its confluence with Rivière-du-Loup (Fig.1).

141

White sucker samples were collected from the Chaudière River KP-0 to KP-1 section in July 2013

142

(n = 3), October 2013 (n = 6) and November 2014 (n = 2), KP-15 to KP-18 section in August 2013

143

(n = 6) and August 2014 (n = 6), and KP-93 in July 2013 only (n = 3) (size > 300 mm). White

144

suckers were also collected from Lake Mégantic in September 2013 (n = 3) close to the Lac-

145

Mégantic dam. For all the aforementioned samples, a transverse slice of 2-3 cm (from the first

146

dorsal fin toward the fish head) was carefully cut off and the fish muscle was retrieved. In

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addition, white sucker juveniles were collected in summer 2014 at seven sampling points

148

following a longitudinal gradient (KP-8.8 to KP-92.5). At each sampling location, the catch


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(comprising between 2–134 juvenile individuals) was pooled. Note that in the present survey,

150

PFASs were analyzed in muscle tissue for adult fish (individual samples) while juveniles were

151

treated as whole-body homogenates (pooled samples at each sampling location).

152 153 154

Fig.1. Map showing the general setting of the Chaudière River watershed and location of the AFFF-impacted site (town of Lac-Mégantic).

155 156

Only a limited number of fish individuals could be sampled for some time points and locations;

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hence, it was deemed beyond the scope of the present survey to perform a detailed temporal

158

trend analysis of the collated fish data.

159

Sediment samples (n = 13) were collected in August–September 2014 in the Lake Mégantic and

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along a longitudinal gradient in the Chaudière River (KP-0.6 to KP-92) (SI Fig.S1). Fish tissue

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and sediment samples were freeze-dried (> 72 h) and ground prior to analysis. The percentage of

162

total organic carbon (TOC) in sediment samples was determined by titration with potassium

163

dichromate and sulphuric acid, with a detection limit of 0.05% (CEAEQ, method MA. 405-C1.1).

164 165

2.3. Chemicals and standards



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Native anionic or neutral PFASs were purchased from Wellington Laboratories, Inc (ON, Canada)

167

or donated by DuPont USA (Wilmington, DE, USA) (see Fig.S2 of the SI for details on chemical

168

structures). 6:2-FTAB was acquired from Shanghai Kingpont Industrial Company, Ltd. Seven

169

cationic or zwitterionic PFASs were custom-synthesized at the Peking Surfactant Institute

170

(Peking, China) to provide additional model analytes for method validation and semi-

171

quantification purposes (SI Fig.S2). Details on solvents and reagents, analyte names, chemical

172

formula, theoretical and measured exact mass and corresponding isotope-labelled internal

173

standards (ISs) (Table S2), as well as a brief description of the synthesis of model cationic or

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zwitterionic PFASs, are all supplied in the SI.

175 176

2.4. PFAS analyses

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A full description of the preparation procedure of samples, procedural blanks, and fortification

178

experiments has been enclosed in the SI. Briefly, sediment samples (1 g dry weight (dw))

179

underwent two ultrasonic extraction cycles with 5 mL of basic methanol (MeOH containing 20 mM

180

sodium hydroxide) and subsequent purification on ENVI-Carb cartridges [31]. Extracts were

181

concentrated to a final volume of 500 µL and neutralized, after which isotope-labeled ISs (2.5 ng

182

each) were added. Fish tissues (0.25 g dw) were extracted by two ultrasonic extraction cycles

183

using 5 mL of MeOH containing 0.1 % (v/v) of ammonium hydroxide. The purification of fish

184

extracts was then performed on Strata X-AW cartridges (Phenomenex, 200 mg/6 mL) and

185

subsequent graphite clean-up (Envi-Carb, 250 mg/6 mL). Following extract blow-down to 500 µL,

186

isotope-labeled ISs (2.5 ng each) were added. Although the analytical workflow was originally

187

developed for anionic and neutral PFASs only, the method could be used to investigate some

188

cationic and zwitterionic PFASs as well, the mixed-mode sorbent allowing satisfactory recovery

189

for the 8 model positive mode PFAS analytes (see also Section 2.6).

190

Instrumental analysis was performed by ultra-high performance liquid chromatography coupled to

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a Q-Exactive Orbitrap mass spectrometer through a polarity switching electrospray ionization

192

source (Thermo Fisher Scientific, Waltham, MA, USA), a 150–1000 m/z mass scan range being

193

applied in full scan MS mode. Orbitrap parameters were set as follows: maximum injection time

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and AGC target were set at 50 ms and 5 x 106, respectively, and resolution at 70,000 FWHM at

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200 m/z [37]. Full details on instrumental operating conditions are provided in the SI.

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2.5. Quality control and LOD/LOQ determination

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Background PFAS contamination originating from the LC system tubing was reduced with a trap

199

column positioned immediately after the aqueous and organic LC mobile phases mixing point but

200

before the injector. The difference in sorbent nature between the trap column (Thermo Hypercarb,

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20 x 2.1 mm, 7 µm) and analytical column (Thermo Hypersil Gold aQ, 100 x 2.1 mm, 1.9 µm)

202

allowed for sufficient delay of PFASs of 6 or more perfluoroalkyl carbon atoms through increased

203

retention in the trap column, while the instrumental contribution of less hydrophobic PFASs

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(namely, PFBA, PFPeA and PFHxA) could not be entirely remediated.

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Procedural blanks were included in each extraction batch and showed low and reproducible

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PFAS levels for both the sediment (n = 6) and biota (n = 6) procedures (SI Table S4). When

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applicable, data were therefore corrected by subtracting the mean blank contribution. Cationic

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and amphoteric suspect-target PFASs were not observed in any procedural blanks or injection

209

blanks.

210

The method detection limits (LODs) for the sediment and fish matrixes were derived from their

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respective matrix-matched calibration curves [38]. Since the levels of the calibration curve were

212

submitted to the preparation process (see also Section 2.6), this approach would allow to

213

integrate potential recovery losses and matrix effects into the LOD determination. In-matrix LODs

214

were in the range 0.008–0.15 ng g-1 dw and 0.005–0.18 ng g-1 ww in sediment and fish muscle,

215

respectively. The limits of quantification (LOQs) were then set at 3 x LOD. Full details on LODs

216

and LOQs for the sediment and fish matrix are reported in the SI (Table S5).

217 218

2.6. Quantification strategy and method performance

219

Pooled sediment samples from the St Lawrence River were used to provide a sediment matrix

220

with low initial PFAS levels for sediment matrix-based fortification experiments. Likewise, white

221

sucker muscle subsamples were pooled to constitute a representative material for fish matrix-

222

based fortification experiments.

223

Whole method recovery was determined as described hereafter [37] (Equation 1):

224

= 100 ∗

Equation 1



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225

Where SB is the analyte to IS response ratio of the sample spiked at the start of the preparation

226

procedure with native analytes, SA is the analyte to IS response ratio of the sample spiked at the

227

end of the preparation procedure with native analytes, and NS is the analyte to IS response ratio

228

of the reference (non-spiked sample). In all three cases, internal standards were added at the

229

end of the preparation procedure.

230

For the sediment analytical procedure, whole-method recovery (n = 3) ranged from 76 to 95 % for

231

the model compounds considered with relative standard deviations (RSDs) in the range 1–25 %

232

(SI Table S6). For the biota analytical procedure, whole-method recovery was in the range 74–

233

101 % except for PFTeDA (41 %), and RSDs remained < 13 % for all model analytes (SI Table

234

S6).

235

Although the spiked sediment matrix was thoroughly vortexed and the residual organic solvent

236

(resulting from spiking the native standards to the sediment matrix) was left to dry before

237

extraction, it should be borne in mind that this methodology may not be entirely representative of

238

the actual system (i.e., sorption/desorption of PFASs in natural sediments in contact to overlying

239

surface water). The actual recoveries from equilibrated sediment samples may be somewhat

240

lower than what our methanolic standard spikes suggest, especially for cationic and zwitterionic

241

PFASs for which strong ionic interactions at the sediment surface might be expected.

242

Similarly, spiking analytes to the fish matrix may poorly reflect the interactions of naturally-

243

assimilated PFASs (i.e. intracellularly bound to the matrix). However, reference samples are now

244

available for PFAS analysis in fish muscle, and may be used to evaluate method trueness, also

245

tantamount to the actual extraction efficiency. In the present study, method trueness was

246

evaluated through the analysis of NIST SRM 1947 Lake Trout reference samples (multi-batch

247

replicate measurements, n = 5). The PFAA concentrations determined in the present method

248

compared favorably with the previously published literature [39,40] (see SI Table S7).

249

Instrumental matrix effects were evaluated by comparing solvent-based analyte to internal

250

standard area ratios (S) to those of sediment or fish muscle extracts spiked post-extraction (M),

251

corrected by the non-spiked sample initial contribution (Ref), as described hereafter [37]

252

(Equation 2):

253

= 100 ∗ 1 −

Equation 2


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Matrix effects were low to moderate when suitable mass-labeled ISs were available, such as for

255

n:2-FTSAs and most PFAAs (SI Table S8). Non-negligible matrix effects were however reported

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for PFTeDA, FOSA, n:3-FTCAs and cationic or amphoteric analytes in the fish muscle, as well as

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for PFOANO and PFOSNO in the sediment. This signaled that matrix-effects were particularly

258

prevalent for analytes without well-matched ISs, advocating in favor of matrix-matched calibration

259

curves for analyte quantitation.

260

Matrix-based calibration curves were designed as follows: incremental levels of PFAS analytes

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(spanning at least 2 orders of magnitude) were added to the sediment and fish matrices at the

262

start of the preparation procedure. The spiked standards were allowed to equilibrate overnight

263

with the sample material, after which the samples underwent their respective extraction and

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clean-up procedures. Isotope-labelled ISs were added to the extracts at the end of the

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preparation procedure for a final concentration of 5 ng mL-1. 6-point matrix-based calibration

266

curves were subsequently built using inverse weighted (1/x) linear regression over 0.1–25 ng mL-

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1

268

Whole-method accuracy and intermediate (intraday/interday) precision were determined at a

269

medium calibration level of 5 ng mL-1 that was not previously included in the calibration curve

270

regression. For these tests, native analytes were spiked to sediment and fish matrix at the

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beginning of the preparation procedure while isotope-labelled ISs were added post-preparation.

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Whole method accuracy ranged between 86–111 % and 78–122 % in the sediment and fish

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matrices, respectively (SI Tables S9-S10). Intra-day precision, representing the RSD of five

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whole method accuracy prepared and analyzed during a single work day, ranged between 2–13

275

% and 1–16 % for the sediment and fish matrix, respectively. Whole method accuracy samples

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were newly prepared and analyzed on a second (n = 5) and third work day (n = 5), and the inter-

277

day precision, derived from the overall RSD (n = 15), remained < 20% for the 30 model PFAS

278

analytes considered (SI Tables S9-S10).

or 0.5– 25 ng mL-1 for all target analytes.

279 280

2.7. Confidence levels in analyte identification and quantification

281

In addition to target PFASs, suspect screening in full scan MS mode was conducted on 23

282

families of infrequently reported anionic, cationic and zwitterionic PFASs, based on the previously

283

published literature [22,23,26,41,42] (see Fig.S3 and Table S3 of the SI for the list of suspect-

284

target analytes). Full-Scan MS chromatograms and interpreted t-MS2 spectra for the major PFAS

285

families identified in the present survey have been enclosed in the SI (Fig.S4-S12). Full-Scan MS



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chromatographic peaks with absolute heights lower than 104 were not considered, and the

287

accurate mass tolerance was set at -5 ppm < δ < +5 ppm. Confidence levels in the identification

288

of target and suspect-target analytes were established following the conventions from

289

Schymanski et al. [34]. Level 1 (confirmed structure) corresponded to analytes for which

290

matching accurate mass, matching MS/MS spectra, and matching retention time with a reference

291

standard were observed (e.g.: PFUnA, PFOS, see SI Fig S5-S6). When confirmation with a

292

reference standard was not possible, analytes were assigned the probable structure confidence if

293

accurate exact mass, plausible MS/MS fragments, and experimental data (e.g., increase of

294

concentrations after the AFFF spill) were simultaneously obtained (Level 2b). When an

295

unambiguous match also existed between the MS/MS fragments observed and PFAS literature

296

spectrum data [22,23], the identification confidence was raised to Level 2a [34] (see

297

Fig.S7,S9,S11,S12 of the SI). In the case of PFASs, the observation of retention time patterns

298

within homologous series with increasing fluoroalkyl chain length could also help in the

299

identification of suspect-target analytes [25,31]. When such patterns were observed within

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families, or when the retention time interval with a related reference compound was in

301

accordance with the expected elution order, this was signaled with a (*) in the confidence level.

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Level 3 (tentative candidate) was assigned when specific MS/MS fragments were obtained

303

concomitantly with high abundance (> 10%) instrumental artifacts, possibly due to matrix co-

304

eluting peaks [43] (see Fig.S10 of the SI for an illustrative example). The lowest level of

305

confidence was Level 4 for which no MS/MS spectra could be generated.

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Analytes were also classified according to the degree of confidence in their quantification,

307

following the previous literature [27,44]. Analytes for which native analytes and suitable

308

corresponding isotope-labelled ISs were available were classified as quantitative (Qn). Native

309

positive mode analytes (PFOAAmS, PFOSAmS, PFOAB, PFOSB, PFOANO, PFOSNO,

310

PFOSAm and 6:2-FTAB) were quantified against

311

semi-quantitative (sQ). Qn and sQ analytes were used as model compounds to evaluate

312

instrumental matrix effects, whole method recovery, whole method accuracy, and precision (see

313

also Section 2.6). In addition, the 150-1000 m/z full scan MS acquisition mode enabled for the

314

screening of other anionic, cationic and zwitterionic suspect-target analytes (SI Fig.S3) (see also

315

SI Table S3). A more detailed description of the quantification strategy for analytes for which

316

authentic standards were not available is enclosed in the SI. Suspect-target analytes for which a

317

similar native compound could be used for quantification were classified as qualitative (Ql). For

318

instance, 8:2-FTAB, 10:2-FTAB and 12:2-FTAB were quantified using the matrix-matched

13

C4-PFOS and were therefore classified as


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calibration curve of the shorter chain fluorotelomer sulfonamide betaine analogue (6:2-FTAB),

320

and n:2 fluorotelomer sulfonamide amines (namely, 6:2-, 8:2- and 10:2-FTA) using that of the

321

perfluoroalkyl sulfonamide amine analogue (PFOSAm). Analytes for which no similar reference

322

standard were available were assigned screen (Sc) data quality level [44]. To illustrate,

323

fluorotelomer betaines (n:3-FTBs and n:1:2-FTBs) concentrations were tentatively estimated

324

using the matrix-matched calibration curve of 6:2-FTAB. Although FTABs and FTBs are both

325

betaine-based PFASs, FTBs lack the sulfonamide group following the fluorotelomer chain and the

326

instrumental sensitivity of FTBs may therefore be very different from that of 6:2-FTAB. Since

327

whole-method accuracy and recovery could not be determined for Ql and Sc analytes,

328

concentration estimates derived for these analytes should therefore be viewed as indicative only.

329

Moreover, we must reiterate that non-detection of suspect-target PFASs would not necessarily

330

equate with the compounds not being present in the samples, especially for Ql and Sc analytes

331

for which no certified standards were available.

332 333

3. Results and Discussion

334 335

3.1. Occurrence, levels and composition profiles of perfluoroalkyl acids (PFAAs)

336

In sediments from Lake Mégantic (n = 5) and Chaudière River (n = 8), up to 6 PFAAs were

337

detected (see Table S11 of the SI for detailed results for each sampling site). Total PFCA

338

concentrations (ΣPFCA) varied between 0.06 and 0.5 ng g-1 dw, a low burden compared to

339

sediments from urban environments in Canada [45] and Europe [46,47] but similar to

340

observations from some remote Canadian Arctic lakes (e.g., North Lake, Nunavut) [40]. PFOS, in

341

contrast, remained systematically below the reported LOD of 0.044 ng g-1 dw. This is in line with

342

composition profiles reported by Lescord et al. [40] who observed relatively high proportions of

343

ΣPFCA in sediments from atmospherically-supplied lakes from the Canadian High Arctic, while

344

those of more locally-contaminated lakes were rather dominated by PFOS.

345

Apart from PFBA and PFOA, other PFAAs generally remained < LOD (SI Table S11), except in

346

the Chaudière River close to the accident site (KP-0.6) where other short-chain PFCAs such as

347

PFPeA, PFHxA and PFHpA were also reported (0.06–0.11 ng g-1 dw). It would seem unlikely that

348

the PFAA profile observed at KP-0.6 arises from impurities in the actual AFFF formulations [27].

349

Alternatively, the high proportion of short-chain PFCAs observed could result from the

350

environmental degradation of fluorotelomer-based PFASs. For instance, Weiner et al. [48]



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screened for fluorosurfactants in AFFF formulations from Ontario, Canada; the authors evidenced

352

significant microbial degradation of 6:2 fluorotelomer mercaptoalkyl amido sulfonate (6:2-FTSAS),

353

which resulted in the formation of short-chain PFCAs (PFPeA, PFHxA and PFHpA). Harding-

354

Marjanovic et al. [49] investigated the aerobic biotransformation of a suite of n:2-FTSASs in

355

AFFF-amended microcosms, also pointing to the significant formation of short-chain PFCAs

356

(PFBA, PFPeA and PFHxA) in live microcosms compared to autoclaved sterile controls. In the

357

present survey, although 6:2-FTSAS could not be detected in sediment samples, we can surmise

358

that short-chain PFCAs originate from the environmental biodegradation of fluorotelomer-based

359

PFASs, either via diffuse sources (such as atmospheric deposition of volatile precursors and

360

subsequent degradation) [50,51] or direct sources (such as AFFF application at the railway

361

accident site and subsequent environmental degradation of the fluorotelomers originally

362

dispersed) [48,49].

363

In adult fish muscle (n = 36), PFOS and long-chain PFCAs (C10–C13) were found systematically,

364

and high detection frequencies were also reported for PFNA and PFTeDA (Table 1). In contrast,

365

short-chain PFCAs (C5-C8) were less recurrent, and PFBS not detected at all. This agrees well

366

with observations that PFAAs of short perfluoroalkyl chain length are less bioaccumulative than

367

their longer chain analogs [46,52]. On the overall dataset (n = 36), ΣPFAA was 3.9 ± 1.8 ng g-1

368

ww on average (median: 3.4 ng g-1 ww; range: 0.9–8.8 ng g-1 ww), nearly 100-fold lower than

369

levels previously reported for bullhead catfish (Ameiurus spp.) or European perch (Perca

370

fluviatilis) near other AFFF-impacted sites [17,19]. With an average contribution of ~ 32 % of

371

ΣPFAA (range: 16–49 %), PFOS was the predominant PFAA in nearly all fish muscle samples. It

372

was followed by PFUnDA (~ 19 % of ΣPFAA), PFTrDA (~ 13 %), PFDA (~ 11 %), PFDoDA (~ 9

373

%), and PFNA (~ 6 %). On average, PFOS levels remained at around 1.2 ng g-1 ww over the

374

period covered by this study (2011–2014; N = 36) (Table 1). This strongly suggests that the

375

AFFFs utilized at Lac-Mégantic derailment site were not PFOS-based. PFOS levels in fish muscle

376

remained ~ 2–40 times lower than the current guideline from the European Union (9.1 ng g-1 ww)

377

or Environment Canada (4.6 or 8.2 ng g-1 ww) for the protection of piscivorous mammals or birds

378

[53,54], and ~ 4000–30000 times lower than that of Environment Canada (8300 ng g-1 ww) for

379

the protection of fish itself [54].

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381 382 383 384


Table 1. Detection frequency and concentration range (min–max) of PFAAs and FOSA in adult white sucker muscle samples from the Lake Mégantic and Chaudière River, arranged according to sampling year. Concentrations are expressed in ng g-1 wet weight (ww) and were blankcorrected when applicable.

385 Detection Frequency (%)

-1

Concentration Range (ng g ww)

2011

2013

2014

2011

2013

2014

(n = 8)

(n = 20)

(n = 8)

(n = 8)

(n = 20)

(n = 8)

PFBA

12.5

30

25

Environmental Occurrence of Perfluoroalkyl Acids and Novel

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