Non-Target Mass Spectrometry Reveals New Perfluoroalkyl

1 hour ago - ... testing should be a priority for understanding the health risks posed to people and wildlife exposed to these substances. View: PDF |...
1 downloads 6 Views 868KB Size
Subscriber access provided by Universitaetsbibliothek | Johann Christian Senckenberg

Environmental Measurements Methods

Non-Target Mass Spectrometry Reveals New Perfluoroalkyl Substances in Fish from the Yangtze River and Tangxun Lake, China Yanna Liu, Manli Qian, Xinxin Ma, Lingyan Zhu, and Jonathan W. Martin Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b00779 • Publication Date (Web): 16 Apr 2018 Downloaded from http://pubs.acs.org on April 16, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 36

Environmental Science & Technology

1

Non-Target Mass Spectrometry Reveals New Perfluoroalkyl Substances

2

in Fish from the Yangtze River and Tangxun Lake, China

3

Yanna Liu,1 Manli Qian,2 Xinxin Ma,3 Lingyan Zhu,3 Jonathan W. Martin1,4*

4

1

5

Pathology, University of Alberta, Edmonton, AB, Canada, T6G 2G3

6

2

Analytical Chemistry Laboratory, Wuxi AppTec, Suzhou, China, 215104

7

3

Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education,

8

College of Environmental Science and Engineering, Nankai University, Tianjin, China, 300071

9

4

10

Division of Analytical and Environmental Toxicity, Department of Laboratory Medicine and

Science for Life Laboratory, Department of Environmental Science and Analytical Chemistry,

Stockholm University, Stockholm, Sweden, 10691

ACS Paragon Plus Environment

1

Environmental Science & Technology

11

Page 2 of 36

ABSTRACT

12

Non-target high resolution mass spectrometry (Nt-HRMS) has proven useful for

13

identification of unknown poly- and perfluoroalkyl substances (PFASs) in commercial products

14

and water, but applications to biological samples are limited. China is the major PFAS

15

manufacturing nation, thus here we adapted our Nt-HRMS methods to fish collected from

16

Yangtze River and Tangxun Lake to discover potentially bioaccumulative PFASs in aquatic

17

organisms destined for human consumption. In addition to traditional PFASs, over 330 other

18

fluorinated analytes belonging to 10 classes of PFASs were detected among the pooled fish

19

livers, including 6 sulfonate classes, 2 amine classes, 1 carboxylate class, and 1 N-heterocycle

20

class. One class was detected in samples from both locations, 8 classes were detected exclusively

21

in Tangxun Lake fish, and 1 class was detected exclusively in Yangtze River fish – 10 km

22

downstream of a fluorochemical manufacturing site where we first reported these substances in

23

wastewater three years ago. Four of the PFAS classes (>165 analytes) are reported for the first

24

time here. Wider monitoring and toxicological testing should be a priority for understanding the

25

health

risks

posed

to

people

and

wildlife

exposed

ACS Paragon Plus Environment

to

these

substances.

2

Page 3 of 36

26

Environmental Science & Technology

INTRODUCTION

27

Many long chain poly- and perfluoroalkyl substances (PFASs) are now globally

28

distributed as environmental contaminants.1, 2 Since their first discovery in the environment 18

29

years ago,1 voluntary industrial phase-outs3-5 and domestic or international restrictions and

30

regulations4-11 have been introduced to limit future emissions. However, there has been a global

31

geographic shift of PFAS manufacturing to countries with fewer restrictions, and a simultaneous

32

shift towards alternative PFASs12-14 with uncertain toxicity and environmental fate. Owing to the

33

environmental persistence of many perfluorinated compounds, there is little evidence that

34

environmental concentrations of legacy PFASs are yet declining,15 thus it is important to identify

35

and prevent new alternative PFASs from spreading globally.

36

After the 3M Company phased out its C8 production in North America and Europe

37

between 2000 and 2002, developing countries (e.g. China) increased their PFAS production,16

38

and contamination of local environments17,

39

between a contaminated environment and local people is well described for fisheries around

40

Tangxun Lake in China.18 Here, wastewater from an industrial region is known to have

41

contaminated the lake water, such that it now contains very high concentrations of long chain

42

PFASs, including perfluorooctanesulfonate (PFOS, 73-1700 ng/L) and perfluorooctanoate

43

(PFOA, 71-1400 ng/L) as well as known alternative-PFASs such as perfluorobutanesulfonate

44

(PFBS, 2200-4500 ng/L) and perfluorobutanoate (PFBA, 1800-6300 ng/L). In blood of fishery

45

employees who live around this lake, and who also likely consume the fish, serum PFOS

46

concentrations were extremely high, up to 31,000 ng/mL.20 Moreover, use of PFASs in China

47

may have global consequences, as shown for F-53B (ClC6F12OC2F4SO3K, CAS No. 73606-19-6),

48

a metal plating mist suppressant chemical used only in China since the 1970s.21-23 F-53B is

18

and of human serum19 has followed. The link

ACS Paragon Plus Environment

3

Environmental Science & Technology

Page 4 of 36

49

detectable in Chinese environmental22-24 and biological samples,24-27 but was also recently

50

detected in Greenland ringed seals and polar bears.28

51

Shorter-chain PFASs and structurally modified long-chain perfluorinated acids, such as

52

those with ether bonds or non-fluorinated carbons, are two broad categories of known

53

alternative-PFASs.13 Manufacturers claim that such alternatives are less bioaccumulative and

54

“safe for their intended use”,29,

55

environmental fate data for these. In many cases the alternative-PFASs, or their predicted

56

breakdown products, do not avoid the problem of environmental persistence. For example,

57

trifluoroacetic acid and PFBS were similarly resistant to microbial degradation as PFOS,31, 32 and

58

perfluoroether chains were as resistant as perfluoroalkyl chains to abiotic and biotic

59

degradation.33 Moreover, shorter-chain alternatives do not necessarily avoid unwanted

60

bioaccumulative properties. Perfluorobutanesulfonamide (a PFBS precursor) was recently

61

detected at 80 ng/g in fish in the Netherlands,34 suggestive of its bioaccumulation potential.

30

but there are few publicly available toxicity studies nor

62

Another concern is that unknown PFASs are now being intentionally manufactured as

63

alternatives or unintentionally produced as byproducts, and that these may already be adding to

64

environmental contamination. At a fluorochemical manufacturing site on the Yangtze River in

65

China, our previous work by non-target high-resolution mass spectrometry (Nt-HRMS) revealed

66

36 new PFASs in wastewater,35 including three PFAS classes that had not previously been

67

reported. Moreover, it is generally reported that >90% of the total mass balance of organic

68

fluorine in environmental36, 37 and biological samples27, 38, 39 is from unknown compounds. These

69

unknowns may be attributable to unidentified legacy PFASs, or to contemporary alternative-

70

PFASs, and it is important to identify these unknowns to evaluate or mitigate risks of PFAS

71

exposure.

ACS Paragon Plus Environment

4

Page 5 of 36

Environmental Science & Technology

72

Nt-HRMS techniques are valuable tools for chemical discovery owing to their high mass

73

spectral resolving power, which reduce interferences, and their high mass accuracy which

74

enables accurate empirical formula prediction. Their successful application to PFAS discovery in

75

water

76

HRMS method for PFAS discovery in water35 to the discovery of potentially bioaccumulative

77

PFASs in fish tissue collected at two commercial fishery locations in China. Details of each

78

chemical discovery and of related environmental and toxicological significance are discussed.

35, 40-42

or in firefighters’ serum43 are already demonstrated. Here we adapted our Nt-

79 80

MATERIALS AND METHODS

81

Samples Collection

82

In October 2015, a commercial fisherman was recruited at each location (Figure S1) to

83

collect fish on their regular routes. One location was on the Yangtze River, in a region

84

approximately 10 km downstream of a wastewater treatment plant (WWTP) that services a major

85

fluorochemical manufacturing park in Changshu, Jiangsu.35 We previously identified new PFASs

86

in influent to this WWTP, and the effluent is known to be released to the Yangtze River.44 The

87

other location was in Tangxun Lake in Wuhan, Hubei. This lake receives discharge from a

88

WWTP that processes both domestic and industrial wastewater and has been identified as a

89

contaminated water body.18

90

Three fish species were obtained at the Yangtze River site, including common carp

91

(Cyprinus carpio), silver carp (Hypophthaimichthys molitrix) and bighead carp (Aristichthys

92

nobilis). The same three species were obtained at Tangxun Lake, as well as a fourth species,

93

white Amur bream (Parabramis pekinensis). Between 3 and 7 individual whole fish were

94

obtained and weighed (whole-fish wet weight) for each species at each location. Whole liver was

ACS Paragon Plus Environment

5

Environmental Science & Technology

Page 6 of 36

95

collected from each individual fish, weighed (wet liver weight), and placed into a clean

96

polyethylene bag with changing of gloves between fish to avoid cross-contamination. Livers

97

were shipped overnight in an ice box to Nankai University (Tianjin, China) where all liver

98

samples, and 10 g potassium chloride granules, as quality control for possible laboratory

99

contamination, were freeze dried, weighed (dry liver weight, Table S1) and shipped to the

100

University of Alberta for analysis.

101

Sample Extraction and Nt-HRMS Analysis

102

The same number of freeze-dried individual livers from the same species at each location

103

were pooled, resulting in 7 fish samples (3 for the Yangtze River and 4 for Tangxun Lake, Table

104

S1). All fish samples (one pooled sample per species at each site) with the procedural blank salts

105

were extracted with acidified acetonitrile and purified with weak anion exchange cartridges

106

(detailed in SI). After successively washing with 2% formic acid, water and methanol, the

107

cartridges were eluted with 1% NH4OH in methanol, and the eluents were subjected to a

108

previously developed non-target HPLC-Orbitrap Nt-HRMS method for PFAS discovery.35

109

Briefly, a combination of in-source fragmentation flagging scan, full-scan and MSn experiments

110

were used to detect and characterize unknown PFASs. Fluorinated fragment ions (e.g. [C2F5]-)

111

detected by in-source fragmentation flagging were used to flag retention times of PFAS

112

molecular ions in full-scan mode. Exact masses (±5 ppm) of the molecular ions, isotopic patterns

113

and in-source fragments were used to assign empirical formulae.

114

For each non-target class of PFAS homologues discovered, plausible structures were

115

proposed based on MSn analyses, and confidence levels (CL=1-4) were assigned according to

116

established criteria.45 Briefly, CL=1 represents confirmed structures by match to reference

117

standards, CL= 2 represents probable structures by comparing to library spectra or by diagnostic

ACS Paragon Plus Environment

6

Page 7 of 36

Environmental Science & Technology

118

evidence, CL=3 represents tentative candidates whose possible structure can be proposed but

119

lack sufficient information to assign an exact structure (e.g. position of a chlorine atom on an

120

aromatic ring), and CL=4 is used when the unknown analyte ion can be assigned an

121

unambiguous formula, but no structural information is available.45

122

Quality Control and Quantification

123

Procedural blanks were injected between samples to check for background responses.

124

Instrumental quantification limits (IQLs), method quantification limits (MQLs), absolute

125

recoveries, absolute matrix effects and absolute total extraction efficiencies were evaluated with

126

a mixed fish liver matrix containing equal amounts of the 7 pooled fish liver samples (detailed in

127

SI). Legacy PFASs were quantified using authentic standards, and non-target PFASs were semi-

128

quantified against structurally similar authentic standards as described in SI and in Table S3.

129 130

RESULTS AND DISCUSSION

131

Method Performance

132

Absolute recoveries of the solid phase extraction method for model mass-labeled PFASs

133

were