Multimedia Distribution and Transfer of Per- and Polyfluoroalkyl

Jun 27, 2018 - MOE Key Laboratory of Pollution Processes and Environmental ... Wadsworth Center, New York State Department of Health, and ... acids (P...
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Environmental Processes

Multi-media Distribution and Transfer of Per- and Polyfluoroalkyl Substances (PFASs) Surrounding Two Fluorochemical Manufacturing Facilities in Fuxin, China Hao Chen, Yiming Yao, Zhen Zhao, Yu Wang, Qi Wang, Chao Ren, Bin Wang, Hongwen Sun, Alfredo C. Alder, and Kurunthachalam Kannan Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b00544 • Publication Date (Web): 27 Jun 2018 Downloaded from http://pubs.acs.org on June 29, 2018

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Multi-media Distribution and Transfer of Perand Polyfluoroalkyl Substances (PFASs) Surrounding Two Fluorochemical Manufacturing Facilities in Fuxin, China

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Hao Chen,a Yiming Yao,a Zhen Zhao,*,a Yu Wang,a Qi Wang,a Chao Ren,a Bin Wang,a

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Hongwen Sun,*,a Alfredo C. Alder, a Kurunthachalam Kannanb

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a

MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China

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Wadsworth Center, New York State Department of Health, and Department of

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Environmental Health Sciences, School of Public Health, State University of New York

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at Albany, Albany, New York 12201, United States

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*Corresponding author: Zhen Zhao ([email protected]),

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Hongwen Sun ([email protected])

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Nankai University

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38 Tongyan Road, Jinnan District, Tianjin 300350, China

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Phone: 86-22-23509241

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ABSTRACT

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Industrial facilities can be point sources of per- and polyfluoroalkyl substances (PFASs)

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emission to the surrounding environment. In this study, twenty-five neutral and ionizable

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PFASs were analyzed in 94 multi-media samples including air, rain, outdoor settled dust,

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soil, plant leaves, river water, surface sediment, and shallow groundwater from two

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fluorochemical manufacturing parks (FMPs) in Fuxin, China, to elucidate the

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multi-media distribution and transfer pattern of PFASs from a point source. The

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concentrations of individual PFASs in air, outdoor settled dust, and surface river water

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decreased exponentially as the distance increases from the FMPs, whereas the

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concentrations of short-chain (C2-C4) perfluoroalkyl carboxylic acids (PFCAs) remained

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high (3000 ng/L) in the surface water 38 km away. At FMPs, air concentrations of

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fluorotelomer alcohols and iodides were found dominant with levels of up to 7900 pg/m3

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and 920 pg/m3, respectively. Trifluoroacetic acid was directly released from FMPs and

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occurred in all the environmental matrices at levels 1-2 orders of magnitude higher than

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other PFCAs. Higher air-water concentration ratios of short-chain PFCAs (C2-C4)

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suggested their transfer tendency from air to water. Both short-chain (C2) and long-chain

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(> C6) PFCAs have greater sediment-water distribution coefficients and deposit dust-air

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coefficients, which have great influences on the long-range transport potential of different

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analogues. 2

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Keywords PFASs; TFA; Fluorochemical industry; Multi-media distribution; Source analyses; Transfer

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1. INTRODUCTION

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As a class of surfactants with good performance, per- and polyfluoroalkyl substances

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(PFASs) have been widely used in numerous industrial and household products.1,2 Due to

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their widespread use, two major sub-categories of PFASs, including ionizable PFASs

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(i-PFASs) like perfluoroalkyl sulfonic acids (PFSAs) and carboxylic acids (PFCAs), and

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to a less extent neutral PFASs (n-PFASs) like fluorotelomer alcohols (FTOHs), have

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been extensively detected in various environmental matrices and attracted more and more

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public attention recently.3-7 Due to the high bioaccumulation potential and toxicity of

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long-chain PFSAs (CnF2n+1SO3H, n≥6) and PFCAs (CnF2n+1COOH, n≥7),8 regulatory

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measures have been proposed. In 2009, perfluorooctane sulfonic acid (PFOS) and its salts

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were added to Annex B of the Stockholm Convention, whereas perfluorooctanoic acid

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(PFOA) has been regulated in many countries and is currently a candidate for listing

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under the Stockholm Convention. The long-chain PFASs have been gradually replaced

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by short-chain analogues,9 and the manufacture of C8 analogues shifted to China.1,10

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Due to the varied properties of different PFASs, PFASs have been detected in multiple

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environmental media, including surface water, sediment, soil, atmosphere, and

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precipitation.3-7 However, till now, majority of the investigation has been focused on only

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one or two media, which is not propitious for accurate assessment on the source, phase

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distribution and primary transfer pathway of PFASs in a specific environment

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surrounding a point source.

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In aquatic environment, sediment is a sink for many contaminants, and associations of

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PFASs with sediment compromise their long-range transport along the current.5 Previous

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literature revealed that long-chain PFASs are strongly associated to sediment due to the

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hydrophobicity of their per- or polyfluoroalkyl chains.11 With the phase-out of long-chain

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PFASs and the substitution with short-chain analogues, it brings concerns that short-chain

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PFASs are more water soluble and have higher long-range transport potential, which also

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leads to higher risk of groundwater contamination.12

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Volatile n-PFASs, once released to the atmosphere, can undergo long-range

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atmospheric transport (LRAT)13 and subsequent photochemical degradation. This process

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for FTOHs constitutes a main source of PFCAs in the atmosphere.14, 15 More recently, it

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was reported that perfluoroalkyl acids (PFAAs) can be directly released into the

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atmosphere and undergo atmospheric transport in a form of aerosols.16-18 PFASs can be

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further associated with larger particles through aging processes, which is more readily

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removed via dry and wet deposition.3 These processes contribute to a great portion of

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PFASs sources in the surface environment, especially for remote areas. To complete the

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cycle, thermodynamic distribution characteristics of PFASs between the atmosphere and

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land surface around a point source is yet to be clarified. 5

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Pot and hydroponic studies have confirmed that i-PFASs especially the short-chain

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analogues can be taken up by plant roots and transferred to plant leaves.19,20 However,

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this process is less efficient for long-chain i-PFASs.19,21 This highlights that high levels of

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some i-PFASs in plant leaves around point sources cannot be solely explained by root

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uptake due to their low soil concentrations.22 Plant leaves may also take up PFASs

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directly from the atmosphere and the process can be more significant around point

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sources.22,23 Multi-media investigations on the distribution and transfer of PFASs in

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plants may provide further field evidences in elucidating the origin of PFASs in leaves.

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Fluorochemical industry parks (FMPs) are important point sources of PFASs to their

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surrounding environment, and even farther areas as a result of transport.22,24,25 Fuxin,

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Liaoning province, is one of the most important fluorochemical industrial centers in

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China.26 Both electrochemical fluorination (ECF) and telomerization techniques are used

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to produce PFASs at FMPs in Fuxin. From several field studies conducted in Fuxin,26-29

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levels of PFAAs were up to several μg/L in surface water, indicating that Fuxin is

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severely impacted by the industrial activities at FMPs. However, majority of the

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investigations above in Fuxin only reported on aquatic environment and only one study

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was about soil, which was not enough to understand the occurrence, phase distribution,

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and transport behaviors of various PFASs surrounding a point source, thus compromises

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proper pollution control strategies to a larger scale. 6

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Currently, the commonly investigated PFASs only contribute to a minor portion of the

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total organofluorine (