Agricultural activities impact on soil and sediment fluorine and perfluorinated compounds in an endemic fluorosis area
Graphical abstract
Introduction
Perfluorinated compounds (PFCs) are anthropogenic organic pollutants which have been widely used in industrial and commercial applications such as surfactants, lubricants, fire retardants, wetting agents and polymer additives (Xu et al., 2020). Currently, PFCs are ubiquitously detected in various environmental compartments and biological samples, including surface water (Pan et al., 2018), groundwater (Bräunig et al., 2017), sediment (Lin et al., 2020), soil (Brusseau et al., 2020), atmosphere (Zhao et al., 2020), as well as wildlife (Jouanneau et al., 2020) and human body (Kim et al., 2020). Due to the chemical inertness and resistance to hydrolysis, enzymatic degradation, and oxidation processes of PFCs in natural environments, they may produce long-term and extensive harm to human health and the environment, which have received considerable scientific and public attention in recent years (Du et al., 2014; Lu et al., 2014). Environment studies about PFCs mainly concentrated on low-molecular-weight surfactants perfluoroalkylcarboxylic acids (PFCAs) and perfluoroalkylsulfonic acids (PFSAs), in which all the carbons are bonded to fluorine atoms, and composing of homologous series of molecules with varied length of carbon chain (Castiglioni et al., 2015). In particular, great attention has been given to the long-chain PFCAs and PFSAs, which are highly persistent and capable of bio-accumulation and biomagnification through the food chain, exerting adverse consequences on animals and humans (Jin et al., 2015; Shi et al., 2018; Li et al., 2019).
As an essential component of terrestrial ecosystems, soil has become a prominent sink for PFCs (Cai et al., 2019; Lan et al., 2020). So far, most of the existing researches on soil PFCs mainly conducted in the soils affected by nearby point sources, such as fluorochemical manufacturing park (Liu et al., 2019; Fang et al., 2020), wastewater treatment plants (Washington et al., 2010; Shigei et al., 2020), and firefighting training ground (McGuire et al., 2014; Baduel et al., 2015). Different with point source contaminated soils, the soils in remote areas are also susceptible to the effects of non-point sources of PFCs, such as agriculture land uses where pesticides have been used or recycled wastewater has been applied for irrigation (Li et al., 2018). The application of biosolids in agricultural practices is a critical way for PFCs to enter the soil (Chen et al., 2020). Greater levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were observed in samples collected near areas of intensive agricultural activities where a large amount of pesticides are applied every year (Wang et al., 2011). Besides, the employment of sewage sludge as manure in some agriculture areas can be a direct source of PFCs contamination in soils (Castiglioni et al., 2015). The PFCs in farmland soils can migrate from soil to crops through roots and to invertebrates by direct contact, posing a serious environmental threat to wildlife and humans (Cai et al., 2019; Liu et al., 2019). Therefore, it is critical and valuable to investigate the PFCs concentrations in farmland soils for health risk control.
Exposure to high levels of fluorine can cause health impacts called fluorosis, which remains a prominent problem in many regions such as Afghanistan, Japan, Iraq, Turkey and India (Singh et al., 2018). China is also a high incidence area of endemic fluorosis, with more than 200 million people being currently threatened by fluorosis (Wang et al., 2019a; Gan et al., 2021). It has been reported that high fluorine regions in southwestern China overlap with phosphorus-containing strata regions (Liu et al., 2020b). As a consequence of phosphate rocks extraction, the fluorine content in the local environment is relatively high. Moreover, the volatilization and transfer of fluorine in thriving phosphate chemical production process often lead to a high level of fluorine in the final produced fertilizers (Yu et al., 2020).The utilization of these fluorine-enriched fertilizers in endemic fluorosis areas significantly increased the fluorine levels in surface soil (Wang et al., 2019b). Therefore, the fluorine contamination in soils is co-affected by natural and anthropogenic sources. Unlike soil fluorine, PFCs are a family of synthetic compounds, which mainly derive from anthropogenic factors in various consumer products during industrial and agricultural processes. Previous studies focused merely on the distribution of inorganic fluorine response to agricultural activities in endemic fluorosis areas, including the total fluorine and water-soluble fluorine (Wang et al., 2019c; Yang et al., 2020), but did not identify whether the use of the high fluorine-enriched fertilizers and other agricultural practices would lead to the occurrence of PFCs in farmland soil. Therefore, a deeper insight into the distribution of the PFCs in soils under the influence of agricultural activities in endemic fluorosis area is necessary. In addition, we are urgently want to know whether there is a correlation between the concentrations of total fluorine and PFCs in soil media.
The present study investigated the contamination of fluorine and 21 kinds of PFCs in agricultural soils and sediments near farmland in an endemic fluorosis area in southwest China. The objectives were to (1) determine the levels and distribution of total fluorine and water-soluble fluorine in soils and sediments under the influence of agricultural activities; (2) characterize the composition and distribution of PFCs in farmland soils as well as sediments; and (3) analyse the correlation among surface soil pH, organic matter (OM), total fluorine, water-soluble fluorine and PFCs. The results of our study might be used to determine potential sources of fluorion in soil and provide references for further management and remediation of contaminated soil in endemic fluorosis areas.
Section snippets
Study area and sample collection
The study area, Shifang City, is located in Sichuan Province, Southwestern China (Fig. 1). The average annual temperature and rainfall of Shifang are 16.8 °C and 338 mm in 2018, respectively, and 77% of the rainfall is in summer (SMPG, 2019). Soils in Shifang City are mainly classified as alluvial soil according to Chinese Soil Genetic Classification System, and there are calcareous alluvial soil, gray-brown alluvial soil and purple alluvial soil in this region. The dominant texture of the
Fluorine in soils
In uncultivated soils, the total fluorine concentration ranged from 416 to 731 mg kg−1, with arithmetic mean and median values of 542 and 538 mg kg−1 (Fig. 2a). The total fluorine concentration in cultivated soils was in range of 360–2001 mg kg−1, with arithmetic mean and median values of 729 and 621 mg kg−1, respectively, showing greater variation of total fluorine concentration in cultivated soils than uncultivated ones, though no statistically significant difference (p > 0.05) was observed
Conclusions
The occurrence of total fluorine, water-soluble fluorine and PFCs in soils and sediments was investigated in an endemic fluorosis area of southwestern China. The level of soil water-soluble fluorine appeared significantly higher in cultivated soils than that in uncultivated soils, suggesting that agricultural activities had a remarkable impact on bioavailable fluorine in farmland. The application of phosphate fertilizer or phosphorous compound fertilizer with high fluorine content was an
CRediT authorship contribution statement
Chun-dan Gan: Conceptualization, Investigation, Methodology, Validation, Writing – original draft, Writing – review & editing. Zhi-wei Gan: Conceptualization, Methodology, Writing – review & editing, Resources, Supervision. Si-fan Cui: Investigation, Resources, Methodology, Supervision. Rui-jun Fan: Investigation, Methodology, Validation. Yuan-zhou Fu: Investigation, Resources, Supervision. Mu-yi Peng: Data curation, Investigation, Resources. Jin-yan Yang: Investigation, Methodology,
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This work was supported by the Strategic Cooperation Project Between Sichuan University and Yibin Municipal Government [2019CDYB-19] and the Chengdu Science and Technology Project [2018-YF05-00760-SN].
References (58)
- et al.
Per- and polyfluoroalkyl substances in soil and sediments: occurrence, fate, remediation and future outlook
Sci. Total Environ.
(2020) - et al.
Perfluoroalkyl substances in a firefighting training ground (FTG), distribution and potential future release
J. Hazard. Mater.
(2015) - et al.
Fate and redistribution of perfluoroalkyl acids through AFFF-impacted groundwater
Sci. Total Environ.
(2017) - et al.
PFAS concentrations in soils: background levels versus contaminated sites
Sci. Total Environ.
(2020) - et al.
Toxicity of perfluorinated compounds to soil microbial activity: effect of carbon chain length, functional group and soil properties
Sci. Total Environ.
(2019) - et al.
Occurrence, sources and health risk of polyfluoroalkyl substances (PFASs) in soil, water and sediment from a drinking water source area
Ecotoxicol. Environ. Saf.
(2019) - et al.
Sources and fate of perfluorinated compounds in the aqueous environment and in drinking water of a highly urbanized and industrialized area in Italy
J. Hazard. Mater.
(2015) - et al.
Perfluorinated compounds in soil, surface water, and groundwater from rural areas in eastern China
Environ. Pollut.
(2016) - et al.
Effect of perfluorooctanoic acid on microbial activity in wheat soil under different fertilization conditions
Environ. Pollut.
(2020) - et al.
Provenance and geochemical behavior of fluorine in the soils of an endemic fluorosis belt, central Iran
J. Afr. Earth Sci.
(2017)
Adsorption behavior and mechanism of perfluorinated compounds on various adsorbents—a review
J. Hazard. Mater.
Environment occurrence of perfluoroalkyl acids and associated human health risks near a major fluorochemical manufacturing park in southwest of China
J. Hazard. Mater.
Remediation of fluoride contaminated soil with nano-hydroxyapatite amendment: response of soil fluoride bioavailability and microbial communities
J. Hazard. Mater.
Occurrence and fate of perfluoroalkyl substances in marine sediments from the Chinese Bohai Sea, Yellow Sea, and East China Sea
Environ. Pollut.
Influence of soil physicochemical properties on the depth profiles of perfluoroalkylated acids (PFAAs) in soil along a distance gradient from a fluorochemical plant and associations with soil microbial parameters
Chemosphere
Per- and poly-fluoroalkyl substances (PFASs) in follicular fluid from women experiencing infertility in Australia
Environ. Res.
Novel and legacy per- and polyfluoroalkyl substances (PFASs) in a farmland environment: soil distribution and biomonitoring with plant leaves and locusts
Environ. Pollut.
Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in Shanghai, China
Sci. Total Environ.
A critical analysis of published data to discern the role of soil and sediment properties in determining sorption of per and polyfluoroalkyl substances (PFASs)
Sci. Total Environ.
Perfluoroalkyl acids in drinking water of China in 2017: distribution characteristics, influencing factors and potential risks
Environ. Int.
Legacy per- and polyfluoroalkyl substances (PFASs) and alternatives (short-chain analogues, F-53B, GenX and FC-98) in residential soils of China: present implications of replacing legacy PFASs
Environ. Int.
Perfluoroalkyl substances in sediments from the Bering Sea to the western Arctic: source and pathway analysis
Environ. Int.
Multiple crop bioaccumulation and human exposure of perfluoroalkyl substances around a mega fluorochemical industrial park, China: implication for planting optimization and food safety
Environ. Int.
Continental-scale distribution and source identification of fluorine geochemical provinces in drainage catchment sediment and alluvial soil of China
J. Geochem. Explor.
Perfluorinated compounds in blood of textile workers and barbers
Chin. Chem. Lett.
Are levels of perfluoroalkyl substances in soil related to urbanization in rapidly developing coastal areas in North China?
Environ. Pollut.
Adsorption of perfluorooctane sulfonate on soils: effects of soil characteristics and phosphate competition
Chemosphere
Concentration profiles and spatial distribution of perfluoroalkyl substances in an industrial center with condensed fluorochemical facilities
Sci. Total Environ.
Per- and polyfluoroalkyl substances in water and soil in wastewater-irrigated farmland in Jordan
Sci. Total Environ.
Cited by (12)
Associations between serum per- and polyfluoroalkyl substances as mixtures and lipid levels: A cross-sectional study in Jinan
2024, Science of the Total EnvironmentRemoval of F<sup>−</sup> from water by magnetic floriform magnesium zirconium hydrotalcite-like material doped with Fe<inf>2</inf>O<inf>3</inf> and ZrO<inf>2</inf>
2022, DesalinationCitation Excerpt :At present, environmental waters are full of various harmful substances due to industrial activities, among which the harm of excessive fluorine in the environment is extremely concerned by environmental science and health science [1–4]. Appropriate amount of fluorine is necessary for the growth of plants and animals, but overmuch fluorine will seriously affect their growth and activity [5–7]. The World Health Organization (WHO) has specified drinking water with a fluorine content exceeding 1.5 mg·L−1 is high fluoride water [8,9].
Concentration and distribution of metals, total fluorine, per- and poly-fluoroalkyl substances (PFAS) in vertical soil profiles in industrialized areas
2022, ChemosphereCitation Excerpt :Depending on the number of carbon atoms, different classes of PFAS may behave similarly in the environment, therefore PFAS can be classified as short-chain or long-chain (Lee et al., 2020). The long-chain PFAS (≥C6 for PFSAs, ≥ C8 for PFCAs) are highly persistent and have the tendency to bioaccumulate in organisms and to biomagnify along the food chain, exerting adverse consequences on the ecosystem and human health (Barhoumi et al., 2022; Gan et al., 2021a). Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) belong to the long-chain PFCAs and PFSAs, respectively.
Thermal assisted heterogeneous activation of peroxymonosulfate by activated carbon to degrade perfluorooctanoic acid in soil
2022, Journal of Environmental Chemical EngineeringCitation Excerpt :In Japan, Ahrens et al. [10] detected that ∑PFCAs (Perfluorocarboxylic Acids) ranged from 0.29 to 0.36 ng/g dry weight in surface sediment and groundwater within landfill leachate from Tokyo, among which plume-L-PFOA recorded 1.8 μg/L. In China, Yan et al. [11] found that PFOA ranged from 23.2 to 298 ng/g dry weight in sewage sludge in Shanghai, and Gan et al. [12] reported that concentrations of Σ PFCAs in soils, that were greatly dominated by PFOA, ranged from 0.508 to 6.83 ng/g, with an average of 2.81 ng/g in agriculture areas in Sichuan. Soil is what links the atmosphere and the hydrosphere, and holds a major role in the conversion and build-up of contaminants in both land-based and aquatic environments.
Fluoride sources, toxicity and fluorosis management techniques – A brief review
2021, Journal of Hazardous Materials LettersCitation Excerpt :Regular and proper use of these products does not cause fluorosis associated diseases. A few decades ago, pesticides and fertilizers were considered as means of F− exposure to humans as they contained high amounts of F− (Patil et al., 2018; Dey Bhowmik and Chattopadhyay, 2019; Gan et al., 2021). Presently, these products are banned and do not account for F− exposure to humans (Kabir et al., 2020).