Exploring the fate, transport and risk of Perfluorooctane Sulfonate (PFOS) in a coastal region of China using a multimedia model

Abstract

Perfluorooctane Sulfonate (PFOS) and related substances have been widely applied in both industrial processes and domestic products in China. Exploring the environmental fate and transport of PFOS using modeling methods provides an important link between emission and multimedia diffusion which forms a vital part in the human health risk assessment and chemical management for these substances. In this study, the gridded fugacity based BETR model was modified to make it more suitable to model transfer processes of PFOS in a coastal region, including changes to PFOS partition coefficients to reflect the influence of water salinity on its sorption behavior. The fate and transport of PFOS in the Bohai coastal region of China were simulated under steady state with the modified version of the model. Spatially distributed emissions of PFOS and related substances in 2010 were estimated and used in these simulations. Four different emission scenarios were investigated, in which a range of half-lives for PFOS related substances were considered. Concentrations of PFOS in air, vegetation, soil, fresh water, fresh water sediment and coastal water were derived from the model under the steady-state assumption. The median modeled PFOS concentrations in fresh water, fresh water sediment and soil were 7.20 ng/L, 0.39 ng/g and 0.21 ng/g, respectively, under Emission Scenario 2 (which assumed all PFOS related substances immediately degrade to PFOS) for the whole region, while the maximum concentrations were 47.10 ng/L, 4.98 ng/g and 2.49 ng/g, respectively. Measured concentration data for PFOS in the Bohai coastal region around the year of 2010 were collected from the literature. The reliability of the model results was evaluated by comparing the range of modeled concentrations with the measured data, which generally matched well for the main compartments. Fate and transfer fluxes were derived from the model based on the calculated inventory within the compartments, transfer fluxes between compartments and advection fluxes between sub-regions. It showed that soil and costal water were likely to be the most important sinks of PFOS in the Bohai costal region, in which more than 90% of PFOS was stored. Flows of fresh water were the driving force for spatial transport of PFOS in this region. Influences of the seasonal change of fresh water fluxes on the model results were also analyzed. When only seasonal changes of the fresh water flow rates were considered, concentrations of PFOS in winter and spring were predicted to be higher than that under annual average conditions, while the concentrations in summer and autumn were lower. For PFOS fluxes entering the sea, opposite conclusions were drawn compared to the concentrations. Environmental risks from the presence of PFOS in fresh water were assessed for this region through comparison with available water quality criteria values. The predicted concentrations of PFOS in the Bohai coastal region provided by the model were lower than the water quality criteria published by the United States ...

Property Estimation of Per‐ and Polyfluoroalkyl Substances: A Comparative Assessment of Estimation Methods

“…For the purposes of environmental remediation and risk assessment, environmental fate modeling has proved to be a useful tool to examine the distribution of these chemicals within the environment (Armitage et al 2009; Wang et al 2012; Liu et al 2015; Kong et al 2018). An important requirement for accurately modeling chemical fate is the availability of reliable physicochemical property data for the chemicals of interest.…”

Risk assessment and source identification of perfluoroalkyl acids in surface and ground water: Spatial distribution around a mega-fluorochemical industrial park, China

“…However, concerns have been raised due to the environmental persistence, toxicity, long-range transport and bioaccumulation properties of PFAAs (Lescord et al, 2015;Liu et al, 2015;Wang et al, 2015). Continuous release of these substances from various products and applications has made them ubiquitous in environments, such as air (Taniyasu et al, 2013a), water (Wang et al, 2012), sediment (Yeung et al, 2013), wildlife (Persson et al, 2013) and even the human body (Kannan et al, 2004).…”

Directional electron transfer mechanisms with graphene quantum dots as the electron donor for photodecomposition of perfluorooctane sulfonate

“…The widespread uses have resulted in the global occurrence of PFOS and related derivatives either from direct use of PFOS, as well as from indirect sources like degradation of perfluorooctane sulfonate precursors (PreFOS) [2,3]. The concentration of PFOS ranges from several to dozens of ng L -1 levels in natural waters, and the concentration can be as high as 120 μg L -1 (ground water) and 2210 μg L -1 (surface water) in airports or other polluted areas [4][5][6]. PFOS has developmental toxicity, immunotoxicity, and hepatotoxicity and can be bio-accumulated in the human body and wildlife tissues, posing potential health risks [7,8].…”

“…According to the previous researches, PFOS decomposition started with the cleavage of -F 2 C-SO 3 H bond, thus the focus of PFOS decomposition was how to realize initial activation of sulfonate group [13,14]. Sulfonate group in PFOS is 4 recalcitrant to traditional advanced oxidation processes (AOPs), while the hydrated electron (e aq -) induced reduction has been recently demonstrated to be effective to activate the sulfonate group [15,16]. However, due to the high reactivity of e aq with other coexistent oxidative species in solution, a large amount of chemical agent (molar concentration, I -: PFOS = 500 : 1) that can promote the e aq production was necessary to ensure fast decomposition kinetics [16].…”

“…Mass Balance of Sulfur and Fluorine ElementsTo further analyze PFOS decomposition process, the mass balance of sulfur and fluorine elements were investigated in this work. The concentrations of Fand SO4 2in the solution were zeroed at 0 h to avoid the influence of original impurity in technical-PFOS. The contents of three main isomers in technical-PFOS from Matrix Scientific were as follows: linear-PFOS, 62.3%；…”