Per- and Polyfluoroalkyl Substances in Surface Water of Fuyang River (Handan Section): Occurrence, Source Apportionment, and Risk Assessment

Abstract

Perfluorinated and polyfluoroalkyl substances (PFASs), as an emerging type of pollutant, always pollute water quality to a certain extent. The occurrence, source, and risk of PFASs in the Fuyang River are not well understood. For the first time, the state of PFASs in the upper Fuyang River (Handan section) was investigated. The results showed that there were 10 types of PFASs with concentrations higher than the limit of quantitation in the surface water of the Fuyang River. The surface water $\rho$ (∑PFASs) ranges from 13.80 to 22.88 $\mathrm{ng}·{\mathrm{L}}^{-1}$. The highest quality score is perfluorooctane sulfonate (PFOS), which is 59.40%. PFASs are mainly composed of long-chain substances. PFASs generally show a trend of gradually increasing downstream. PFASs have the same source, mainly from industrial activities around rivers and rainfall inputs. Principal component analysis shows that PFASs mainly come from the leather and textile manufacturing industries, fluoropolymer production, and electroplating metal industries. The concentration of PFASs in the Fuyang River has not yet affected ecology and health.

1. Introduction

Per- and polyfluoroalkyl substances (PFASs) are a new type of artificially synthesized organic environmental pollutant. In their molecular structure, fluoride ions partially or completely replace hydrogen atoms connected to carbon atoms on the base chain. PFAS molecules must contain ${\mathrm{C}}_{\mathrm{n}}{\mathrm{F}}_{2\mathrm{n}+1}$ structures, and their ends contain hydrophilic functional groups [1]. They can be divided into two categories based on their functional groups. They are perfluoroalkyl sulfonic acid (PFSA) and perfluoroalkyl carboxylic acid (PFCA), respectively. Fluoride ions have strong electronegativity. The electrical energy of the C-F bond can reach 485 $\mathrm{kJ}/\mathrm{mol}$. This gives the compound high chemical stability and high resistance to biodegradation processes [2,3,4]. Meanwhile, PFASs have special physicochemical properties such as good surface activity, oil repellency, hydrophobicity, acid resistance, and high temperature resistance [5,6]. Their products have opened up markets in the fields of industry, daily life, and agriculture [7]. The main application pathways of PFASs can be divided into three types. Firstly, they are used as a surfactant to improve the waterproof and oil-resistant properties of clothing, decoration, indoor textiles, and leather. Secondly, they are used as a protective agent and added during the loading and molding process to improve the waterproof properties of the material. Thirdly, they are used as a functional chemical and are used in the production of lubricants, coatings, fire extinguishers, cleaning agents, and pesticide additives. PFASs are widely used, making them detectable in various environmental media, such as the atmosphere [8,9], water bodies [10,11], sediments [2,12], and organisms [13,14,15]. PFASs not only have persistence in environmental media but also pose significant risks to human health. PFASs can induce respiratory [16], thyroid [17], renal [18], and reproductive [19] system diseases. Currently, the persistence, toxicity, and bioaccumulation of PFASs have received attention. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were added to the Stockholm Convention as persistent organic pollutants (POPs) in 2009 and 2019 [20,21], respectively. In 2022, the General Office of the State Council of China released the Action Plan for the Control of Emerging Contaminants. It comprehensively deploys the treatment of Emerging Contaminants, including PFASs. Although PFASs are increasingly being regulated by more and more countries, in recent years, they have been detected to be distributed in water sources around the world, such as in Australia, the United States, Japan, and China [22,23,24,25].

China is the world’s largest producer of PFASs [26]. Water bodies are important gathering places for various sources of pollution [27]. For PFASs with certain solubility, they are more likely to adhere to surface water bodies [28]. Due to frequent industrial and urban activities, PFASs in water bodies are also released again through pathways [29]. Currently, research on the occurrence, source apportionment, and risk assessment of PFASs in water bodies is mostly focused on coastal waters [30,31] and economically developed areas [32,33]. However, there is relatively little research on the rivers in the Haihe River Basin located in inland China. As a tributary of the Ziya River in the Haihe River Basin, the Fuyang River plays an important role in local flood control, irrigation, drainage, and economic and ecological development. At present, there are many studies on nitrogen and phosphorus [34], heavy metals [35], and other pollutants in the Fuyang River. However, there is relatively little research on PFASs. This paper investigated 24 PFASs in the surface water of the Fuyang River (Handan section). We analyzed the occurrence state of PAFSs and evaluated their pollution situation. At the same time, we analyzed the pollution sources of PFASs and evaluated their risks. This paper aims to provide a decision-making basis and theoretical support for the future research and control of PFASs in the Fuyang River and similar water bodies.

2. Materials and Methods

2.1. Experimental Reagents and Instruments

The target compounds of this article are shown in

Table 1. List of target compounds.

Target Compounds		Target Compounds
PFBA	perfluorobutanoic acid	PFPeA	perfluoropentanoic acid
PFHxA	perfluorohexanoic acid	PFHpA	perfluoroheptanoic acid
PFOA	perfluorooctanoic acid	PFNA	perfluorononanoic acid
PFDA	perfluorodecanoic acid	PFUnDA	perfluoroundecanoic acid
PFDoDA	perfluorododecanoic acid	PFTrDA	perfluorododecanoic acid
PFTeDA	perfluorotetradecanoic acid	PFHxDA	perfluoropalmitic acid
PFODA	perfluorooctadecanoic acid	PFBS	perfluorobutane sulfonate
PFHxS	perfluorohexane sulfonate	PFOS	perfluorooctane sulfonate
PFDS	perfluorooctanesulfonate	PF-3,7-DMOA	perfluoro-3,7-dimethyloctanoic acid
PFPeS	perfliuoropentane sulfonate	8-2FTS	1H,1H,2H,2H-perfluorodecane sulfonate
PFHpS	perfluoroheptane sulfonate	PFNS	perfluorononane sulfonate
4-2FTS	1H,1H,2H,2H-perfluorohexane sulfonate	6-2FTS	1H,1H,2H,2H-perfluorooctane sulfonate

. All standard products were purchased from Alta Technology Limited Company (Tianjin, China). Reagents and experimental materials information can be found in

Table 2. List of reagents and experimental materials.

Reagents and Experimental Materials	Grade/Purity	Manufacturer and Producing Area
Methanol	LC-MS grade	MREDA, America
Formic acid	LC-MS grade	Aladdin Reagent, China
Acetonitrile	LC-MS grade	MREDA, America
Ammonium acetate	HPLC grade	GENERAL-REAGENT, China
Ammonia	LC-MS grade	Aladdin Reagent, China

. Equipment and instruments information can be found in

Table 3. List of equipment and instruments.

Instrument	Type Specification	Manufacturer
Liquid chromatography triple quadrupole mass spectrometer	A/B SCIEX 5500+	A/B SCIEX, USA
Chromatographic column	${\mathrm{ACQUITYUPLC}}^{\circledR }\mathrm{HSS} \mathrm{T}3 1.8 \mathsf{\mu }\mathrm{m}$	Waters, China
Solid-phase extraction	CNW16 Solid Phase Extraction Vacuum Device	Anpel, China
Solid-phase extraction column	HLB	Waters, China
Filter membrane	$0.22 \mu \mathrm{L}$	Anpel, China
Electronic analytical balance	SQP	Sartorius, Germany
Pure water filter	Milli-Q Direct16	Millipore, USA

.

2.2. Sample Collection and Preservation

The sampling area is located in the Fuyang River Basin of Handan City, Hebei Province, China. Five sampling points (S1–S5) are located in Fengfeng Mining Area, Cixian County, Hanshan District, Congtai District, and Yongnian District, respectively. The sampling sites are near a representative hydrological station in the hydrological station network of Handan City. S1 is the source of the Fuyang River and also the source of drinking water for Handan. S2 is the source of drinking water in Handan. S3 and S4 are, respectively, the entrance and exit points of the Handan section of the Fuyang River. S5 is a concentrated area for agricultural planting. The existing sampling points have covered different counties and districts in Handan City, so they have certain representativeness in revealing the characteristics of emerging pollutants in the surface water of the Fuyang River. The sampling point information is shown in

Table 4. Information on the sampling sites in the Fuyang River, Handan.

Sampling Points	Longitude (°E)	Latitude (°N)	Elevation
S1	114.2077	36.4234	144
S2	114.3210	36.3982	96
S3	114.4852	36.5647	56
S4	114.5259	36.6958	55
S5	114.7659	36.6826	48

, and the layout diagram of the sampling points is shown in Figure 1. The sampling work was carried out on 29 March 2024. The sampling point for sample collection is located in the center of the river, 0.5–1.0 $\mathrm{m}$ below the water surface. Collect 1L water samples using an oxidation-resisting steel bucket pre-washed three times. Put them into a polypropylene bottle and label the sampling location and time. The collected samples are stored at low temperature in a refrigerated box. And promptly transport them back to the laboratory. Perform subsequent pretreatment and analysis under 4 °C storage conditions.

2.3. Sample Extraction

Firstly, install the solid-phase extraction column on the device. And sequentially add 4$\mathrm{mL}$ of 0.1% ammonia/methanol solution, 4$\mathrm{mL}$ of methanol, and 4$\mathrm{mL}$ of pure water for activation. Always keep the stigma moist. Secondly, connect the upper end of the solid-phase extraction column to a universal adapter. Absorb the sample through a pipeline under negative pressure and control the flow rate to 1 drop/second. Again, rinse the solid-phase extraction column with 4$\mathrm{mL}$ 25$\mathrm{mmol}/\mathrm{L}$ ammonium acetate aqueous solution (5.2 $\mathrm{g}$). At this point, 24 perfluorinated compounds were fixed on the solid-phase extraction column, while the previous samples and eluents were discarded. From then on, rinse sequentially with 4$\mathrm{mL}$ of methanol and 4$\mathrm{mL}$ of ammonia/methanol solution, collect the eluent, and concentrate it using a nitrogen blower. Finally, dilute it to 1 $\mathrm{mL}$ using methanol and transfer it through a 0.22$\mathsf{\mu }\mathrm{m}$ filter membrane to a 1.5$\mathrm{mL}$ brown injection bottle. Subsequently, LC-MS/MS analysis was performed.

2.4. Instrument Analysis

The detection instrument used is a liquid chromatography triple quadrupole mass spectrometer. The ion source is electro spray ion negative ion scanning and multiple reaction monitoring mode analysis. The injection volume is 2 $\mathsf{\mu }\mathrm{L}$ and separation is carried out using an Acquity UPLC^®HSS T3 chromatography column. The mobile phase includes two phases, A and B, as shown in

Table 5. LC-MS/MS instrument parameters for the quantification of target PFASs.

Instrument Model	Acquity UPLC ® HSS T3 chromatographic column
Column temperature	40 °C
Mobile phase	5 mmol/L ammonium acetate aqueous solution PH = 7 (A) acetonitrile (B)
Gradient	Time $\left(\min \right)$	Velocity of flow $(\mathrm{mL}/\min )$		$\mathrm{A} (\%$)	$\mathrm{B} (\%$)
	Initial time	0.3		80	20
	14	0.3		10	90
	16	0.3		10	90
	16.01	0.3		80	20
	20	0.3		80	20
Mass spectrometry parameters	Capillary voltage		4500 V
	Desolvation temperature		500 °C
	Desolvation gas flow		50 mL/min
	Cone gas flow		50 mL/min

. The monitoring ions and mass spectrometry parameters of the target compound are shown in

Table 6. List of target perfluorinated compounds in the present study and the optimized LC-MS/MS parameters.

Substance	Mother Ion/Daughter Ion	Cone Voltage (V)	Collision Energy (V)
PFBA	213/169	40	13
PFPeA	263/219	40	10
PFHxA	313/269	45	13
PFHpA	363/319	30	14
PFOA	413/369	40	14
PFNA	463/419	35	16
PFDA	513/469	40	18
PFUnDA	563/519	70	16
PFDoDA	619/569	70	18
PFTrDA	663/619	65	20
PFTeDA	713/669	85	20
PFHxDA	813/769	90	18
PFODA	913/869	40	25
PFBS	299/80	90	90
PFHxS	399/80	90	90
PFOS	499/80	105	110
PFDS	599/80	120	124
PF-3,7-DMOA	513/469	50	16
PFPeS	349/80	120	72
PFHpS	449/80	150	106
PFNS	549/80	170	120
8-2FTS	527/507	75	28
4-2FTS	327/307	115	34
6-2FTS	427/407	145	40

. The data analysis was conducted using Masslynx v3.3 software.

2.5. Risk Assessment

Risk quotient (RQ) is the most commonly used and widely used method for risk assessment [36]. It is related to the measured environmental concentration (MEC) and the predicted no-effect concentration (PNEC). RQ is specifically expressed as the ratio of the MEC to the PNEC [37], as shown in Equation (1).

$$\mathrm{RQ}={\displaystyle \frac{\mathrm{MEC}}{\mathrm{PNEC}}}$$

(1)

At present, there are not many toxicological data reports on PFASs, especially the lack of clear regulations on environmental benchmark concentrations. Therefore, this study mainly used the PNEC as the environmental baseline concentration for the ecological risk assessment of PFOA, PFOS, PFHxA, and PFNA. There are different discussion results regarding PNEC values in relevant reports. After integrating the relevant literature, the PNEC values of PFOA, PFOS, PFHxA, and PFNA in water were set to 570,000, 1000, 97,000, and 100,000 $\mathrm{ng}·{\mathrm{L}}^{-1}$, respectively [38,39,40]. Risk assessment can be divided into four levels, as shown in

Table 7. The level of risk assessment.

RQ	Grade
RQ < 0.01	Minimal risk
0.01 ≤ RQ < 0.1	Low risk
0.1 ≤ RQ < 1	Medium risk
RQ ≥ 1	High risk

[41].

Health risk quotient (HQ) can assess the potential risks of PFASs to human health. Estimate the health risks of different age and gender groups using the measured environmental concentrations (MECs) and drinking water equivalent level (DWEL) of target compounds in drinking water. Here, people’s ages are divided into 7 categories. They are 3–6, 7–11, 12–16, 17–19, 20–24, 25–29, and >60 years old. In order to reduce the uncertainty of HQ and the possibility of HQ values exceeding 1, this paper establishes a high exposure scenario based on the 95% data of the concentration range [42]. HQ represents the level of human health risk [43], as shown in Equations (2) and (3).

$$\mathrm{HQ}={\displaystyle \frac{\mathrm{MEC}}{\mathrm{DWEL}}}$$

(2)

$$D\mathrm{WEL}={\displaystyle \frac{\mathrm{P}\times \mathrm{ADI}\times \mathrm{BW}}{\mathrm{DWI}\times \mathrm{AB}\times \mathrm{FOE}}}$$

(3)

where P is the proportion coefficient of PFASs ingested through drinking water, taken as 0.2 [44]. ADI refers to the accepted daily intake. The ADIs for PFBS, PFHxA, PFHxS, PFHpA, PFOA, PFOS, and PFNA are 500, 100, 5, 100, 0.2, 0.15, and 4.15 $\mathsf{\mu }\mathrm{g}·{\left(\mathrm{kg}·\mathrm{d}\right)}^{-1}$, respectively [45,46] (Riva et al. 2018). BW represents body weight ($\mathrm{kg}$), DWI represents drinking water intake ($\mathrm{L}·{\mathrm{d}}^{-1}$); specific reference values are shown in

Table 8. Mean body weight ($\mathrm{BW}$) and quantity of drinking water intake ($\mathrm{DWI}$) for different age/gender groups in China.

		Age	3–6	7–11	12–16	17–19	20–24	25–59	>60	Reference
	Sexual Distinction
$\mathrm{BW}$$/\mathrm{kg}$	Male		19.63	33.84	55.16	63.43	67.2	70.77	67.1	[48]
	Female		18.65	31.94	49.44	52.67	53.8	58.37	59.45
$\mathrm{DWI}$$/(\mathrm{L}$$/\mathrm{d}$)			1.08	1.24	1.73	2.26	2.81	2.81	2.81	[49]

. AB is the gastrointestinal absorption rate, taken as 1 [46]. FOE is the exposure rate, taken as 0.96 [47]. PFASs typically appear in the form of mixtures in aquatic environments. In order to evaluate the harm of PFASs to human health, it is necessary to consider the cumulative toxicity of PFASs. According to the funnel hypothesis theory, the HQ equation of PFASs is shown in Equation (4).

$${\mathrm{HQ}}_{\mathrm{mix}}=\sum _{i=1}^{\mathrm{n}}{\mathrm{HQ}}_i=\sum _{i=1}^{\mathrm{n}}{\displaystyle \frac{{\mathrm{MEC}}_i}{{\mathrm{DWEL}}_i}}$$

(4)

where ${\mathrm{HQ}}_{\mathrm{mix}}$ is the cumulative health risk value of PFASs. ${\mathrm{HQ}}_i$, ${\mathrm{MEC}}_i$, and ${\mathrm{DWEL}}_i$ are the $\mathrm{HQ}$, $\mathrm{MEC},$ and $\mathrm{DWEL}$ of the i-th PFAS, respectively.

At present, there is a lack of health risk assessment parameters for PFASs. This paper only conducted health risk assessments on PFBS, PFHxA, PFHxS, PFHpA, PFOA, PFOS, and PFNA. This paper draws on the research of Thomaidi et al. [42] to classify health risk assessment into three levels. They are, respectively, $\mathrm{HQ} \ge$ 1 (PFASs have an undeniable adverse impact on human health), 0.2 $\le \mathrm{HQ} <$ 1 (there is an uncertain risk of PFASs), and $\mathrm{HQ} <$ 0.2 (the health risks caused by PFASs to human health can be negligible) [42,47].

3. Results and Discussion

3.1. Occurrence Characteristics and Composition Structure

This paper detected a total of 24 target compounds in the surface water. Among them, there were 10 compounds with concentrations higher than the limit of quantitation (LOQ) of the method. At least seven types of PFAS were detected at each point, as shown in

Table 9. Concentration ($\mathrm{ng}·{\mathrm{L}}^{-1}$) and detection frequencies ($\%$) of PFASs in the samples.

		Concentration
	Compound	$\mathbf{Min}$	$\mathbf{Max}$	$\mathbf{Mean}$	DF
Short-chain PFASs	PFBA	<LOQ	0.819	0.164	20
	PFHxA	0.297	2.199	0.996	100
	PFHpA	<LOQ	0.428	0.234	80
	PFBS	0.385	2.157	1.000	100
	PFHxS	1.288	7.582	3.142	100
	PFPeS	<LOQ	0.114	0.023	20
Long-chain PFASs	PFOA	0.302	2.849	1.630	100
	PFNA	0.149	0.352	0.215	80
	PFODA	<LOQ	0.294	0.114	60
	PFOS	7.135	11.281	10.758	100
Total PFASs	Short-chain PFASs	2.677	10.150	5.559	70
	Long-chain PFASs	7.731	19.255	12.717	85
	∑24PFASs	13.797	22.880	18.275	76

Note: LOQ: Limit of quantitation (0.4 $\mathrm{ng}·{\mathrm{L}}^{-1}$). LOD: Limit of detection (0.1 $\mathrm{ng}·{\mathrm{L}}^{-1}$).

and Figure 2. This indicates that PFASs are widely present in the Fuyang River. Among the 10 PFASs detected in the surface water, the detection frequencies (DFs) of PFHxA, PFBS, PFHxS, PFOA, and PFOS were 100%, indicating that they were detected at all sampling points. The DFs of PFHpA and PFNA were 80%, and the DF of PFODA was 60%. The minimum DFs for PFBA and PFPeS were 20%.

The concentration of PFASs is shown in Table 9. In the surface water of the Fuyang River, $\rho$(∑PFASs) is 13.797–22.880 $\mathrm{ng}·{\mathrm{L}}^{-1}$ (average value is 18.275 $\mathrm{ng}·{\mathrm{L}}^{-1}$). The highest point is located in S3 (Zhangzhuang Bridge, Hanshan District), and the lowest point is located in S4 (Suli Floodgate, Congtai District). PFCAs are mainly composed of PFOA and PFHxA, with concentrations ranging from 0.302–2.849 $\mathrm{ng}·{\mathrm{L}}^{-1}$ and 0.297–2.119 $\mathrm{ng}·{\mathrm{L}}^{-1}$, respectively. The average concentrations are 1.630 $\mathrm{ng}·{\mathrm{L}}^{-1}$ and 0.996 $\mathrm{ng}·{\mathrm{L}}^{-1}$, respectively. The highest concentrations of PFOA and PFHxA appeared at point S5 (Lianhuakou, Yongnian District). The sampling point was surrounded by villages with dense farming, and the collected surface water flow rate was extremely low. It is possible that rural domestic sewage and other wastewater are directly discharged into the environment without treatment. Subsequently, they flow into the surrounding surface water through surface runoff [50], resulting in a higher concentration. PFSAs are mainly PFOS, with a concentration range of 7.135–16.618 $\mathrm{ng}·{\mathrm{L}}^{-1}$ and an average concentration of 10.758 $\mathrm{ng}·{\mathrm{L}}^{-1}$. The highest concentration of PFOS occurs at point S4 (Suli Floodgate, Congtai District).

Table 9 summarizes the DFs of 10 PFASs in the surface water of the Fuyang River. According to the OECD definition [51], PFCAs with a carbon chain length $\ge$ 7 and PFSAs with a carbon chain length $\ge$ 6 are long-chain PFASs. Among the 10 compounds with concentrations higher than the LOQ of the method, 6 are short-chain PFASs and 4 are long-chain PFASs. Table 9 shows that the DFs of the short- and long-chain PFASs in the surface water are 70% and 85%. PFHxA, PFBS, and PFHxS account for 71.43% of the DFs of short-chain PFASs. Similarly, PFOA and PFOS also account for 58.82% of long-chain PFASs’ DFs. This indicates that PFASs with carbon chain lengths of 6 and 8 (C6-PFAS and C8-PFAS) dominate in short- and long-chain PFASs, with significant advantages in DFs. With the deepening understanding of the hazards of long-chain PFASs in academia, the prohibition and substitution of such substances by short chains have become inevitable [52]. This prohibition and substitution will ultimately affect the occurrence status of such pollutants in the medium. However, according to Figure 2, the mass fraction of long-chain PFASs in the surface water of the Fuyang River is much higher than that of short-chain PFASs, accounting for 70.21% of PFASs. It can be seen that the pollution of long-chain substances in the surface water of the Fuyang River is severe, with PFOS accounting for 59.40% of the total mass of PFASs.

From the detection of PFASs in the surface water, it can be seen that the content of PFOS is the highest (10.758 $\mathrm{ng}·{\mathrm{L}}^{-1}$), followed by PFHxS (3.142 $\mathrm{ng}·{\mathrm{L}}^{-1}$) and PFOA (1.630 $\mathrm{ng}·{\mathrm{L}}^{-1}$). Based on this, the concentration characteristics of PFASs in some important rivers and lakes in China are summarized, as shown in

Table 10. Comparison of PFASs in surface water of different regions.

Study Area	Sample Time	Number of PFASs	Concentration				Reference
			$\sum$PFASs	PFOS	PFHxS	PFOA
Fuyang River	2024	10	13.8–22.9	7.1–16.6	1.3–7.6	0.3–2.9	This paper
Yangtze River	2013	18	2.2–74.6	N.D.–3.1	N.D.–4.5	0.5–18.0	[53]
Pearl River	2012	13	3.0–52.0	0.5–11.0	N.D.–1.0	0.7–8.7	[54]
Songhua River	2017	15	6.4–32.0	N.D.	N.D.–1.1	N.D.–1.7	[55]
Yalu River	2017	15	6.3–28.0	N.D.	N.D.	N.D.–2.2	[55]
Haihe River	2010	9	12.0–74.0	2.0–17.6	N.D.	14.4–42.1	[56]
Liaohe river	2012	11	44.4–781.0	0.1–9.5	N.D.	0.7–61.6	[57]
Qinglong Lake	2021	12	3.6–467.0	N.D.–5.0	N.D.–6.0	N.D.–342.0	[41]
Tai Lake	2009	10	10.6–36.7	10.6–36.7	N.D.–6.5	10.6–36.7	[58]
Baiyang Lake	2016	10	140.5–1828.5	N.D.–12.7	2.1–1688.0	13.6–441.0	[59]
Qiandao Lake	2017	5	1.7–6.2	N.D.	N.D.	0.5–3.6	[60]

Note: N.D.: Not Detected.

. The detection concentration of $\sum$PFASs is equivalent to that of the Taihu Lake. $\sum$PFASs concentrations are significantly higher than the Qiandao Lake and lower than other regions, indicating a lower concentration level, perhaps because the research area is located in the upper reaches of the Fuyang River, and the route area is mainly urban, without passing through the industrial concentration area. The main source of PFASs pollution is human emissions. The detection concentration of PFOS is comparable to that of Baiyangdian and Haihe. The PFOS concentration was significantly lower than that of the Taihu Lake, higher than that of other regions, and was at a lower concentration level. The detection concentration of PFOA, which is also a long chain, is comparable to that of the Qiandao Lake, Songhua River, and Yalu River, lower than other regions, and at a lower concentration level. The detection concentration of short-chain PFHxS is equivalent to that of the Qinglong Lake and the Taihu Lake. It is significantly lower than Baiyangdian and higher than other regions, at a moderate concentration level. The pollution of long-chain PFASs in this study area is still at a relatively high level compared to short chains, indicating that the substitution effect of short chains in the study area is still not significant.

3.2. Spatial Distribution and Source Analysis

According to Figure 3a, there are significant spatial differences in the concentration of PFASs in the Fuyang River. The concentration of ∑PFASs in the downstream of the Handan section of the Fuyang River is generally high. The lowest point is located in Hanshan District (S3), and the highest point is located in Congtai District (S4). The overall trend of ∑PFASs in the study area is gradually increasing downstream. According to Figure 3b, the individual PFASs in the surface water of the Fuyang River can be determined. It is not difficult to see that PFOS is the main pollutant in the surface water of the Fuyang River, with Congtai District (S4) having the highest pollution concentration. PFHxS has the highest pollutant concentration at the Fengfeng mining area (S1). PFOA has the highest concentration of pollutants at sampling point S5 in Yongnian District.

Source analysis can provide an important theoretical basis for the treatment of persistent organic pollutants [61]. It is also necessary to analyze the source of PFASs, but the source of PFASs in the Fuyang River is still unclear. Current research has shown that correlation analysis between PFASs can effectively infer their potential sources [62]. After excluding PFASs with a detection rate of less than or equal to 20%, a 5 × 8 matrix sequence is introduced into the model to analyze the potential sources of PFASs in the surface water of the Fuyang River. The Spearman correlation analysis between various PFASs in the water body is shown in Figure 4. PFHxA is significantly positively correlated with PFHpA and PFOA (p < 0.01). PFHpA is significantly positively correlated with PFHxA (p < 0.01). PFNA is significantly positively correlated with PFHxA, PFHpA, and PFOA (p < 0.05). The above results indicate that they may have the same source.

The ratio method is also an important method for studying the source of PFASs, tracing the source by analyzing the PFHpA/PFOA and PFOA/PFNA values in surface water. According to reports [63], atmospheric deposition is the main source of surface water PFHpA, and the main source of PFOA is surface water. Therefore, PFHpA/PFOA can serve as an effective tracer for atmospheric deposition. A PFHpA/PFOA value greater than 1 indicates the presence of atmospheric deposition, while a PFHpA/PFOA value less than 1 indicates that atmospheric deposition is not the main source of pollution [64]. In this paper, the values of PFHpA/PFOA were all less than 0.22, indicating that atmospheric deposition may not be the main source of PFASs in the surface water of the Fuyang River. When determining the source of PAFSs based on the PFOA/PFNA values, PFOA/PFNA < 7 indicates that PFASs come from atmospheric transportation, 7 < PFOA/PFNA < 15 indicates that PFASs are directly discharged from factories, and PFOA/PFNA > 15 indicates that PFASs are precursor degradation [65,66]. In this paper, the PFOA/PFNA of Ci Country (S2) and Hanshan District (S3) was less than 7, while the PFOA/PFNA of Congtai District (S4) and Yongnian District (S5) was greater than 7 and less than 15. This indicates that there are differences in the sources of PFASs in the upstream and downstream of the Fuyang River. Upstream PFASs may originate from atmospheric transportation, while downstream PFASs may be direct emissions from factories. Combining two ratios, the main sources of PFASs in the Fuyang River are industrial activities and rainfall inputs around the river.

Principal component analysis (PCA) can provide a clearer understanding of the potential sources of pollutants in the environment. Therefore, it is widely used in the analysis of environmental pollutant sources [67]. The KMO and Barrett tests indicate that the KMO value of surface water PFASs in the study area is 0.632 (>0.5), and the P-value of sphericity test is 0.00 (<0.05). This indicates that the data in this paper meet the conditions for PCA analysis. PCA analysis was performed on PFASs content data with a detection rate of over 20% in the surface water at five locations. The principal component loading plot is shown in Figure 5. Among the principal component factors, the first factor accounts for 81.97%, the second factor accounts for 10.06%, and the third factor accounts for 7.41%, which can explain 99.44% of PFASs in the surface water. The PFASs of the study area are mainly derived from three different types of pollution sources, similar to the sources of compounds. PFHpA, PFOA, PFNA, and PFHxA in PC1 have higher loads. PFHpA and PFHxA are substitutes for long-chain PFASs [68]. PFHpA is the decomposition product of anti-fouling and anti-fat coatings on sofas and carpets [69]. PFHxA is the final product in the production process of C6 fluoropolymer acrylic polymers [70]. PFNA salt compounds are used as basic processing aids in fluoride production processes [71]. PFOA is the most commonly used PFAS in industry, mainly derived from the emulsification of rubber products, food packaging processes, paper processing, and flame retardancy of textiles [72]. Therefore, PC1 can be interpreted as the production of leather, textile manufacturing, and fluorinated polymers. PFBS and PFHxA in PC2 have higher loads. PFBS in surface water may originate from atmospheric deposition and may be related to the degradation products of NMeFBSE [73]. Therefore, PC2 can be explained as related to the production and degradation process of fluorinated compounds. PFOS in PC3 has a higher load. The existence of PFOS can be attributed to industrial emissions from electroplating and petrochemical industries [74]. Therefore, PC3 can explain the impact of the metal electroplating industry.

3.3. Risk Assessment

The Fuyang River is the only river with a base flow in Handan City and is the “mother river” of the people of Handan [75,76]. Water quality is closely related to human health; therefore, RQ and health HQ are conducted on PFASs in water bodies.

Due to the current lack of risk assessment parameters for PFASs, ecological risk quotients are only conducted on PFOA, PFOS, PFHxA, and PFNA. According to Equation (1), the RQ values of four PFASs in the Fuyang River can be obtained, as shown in Figure 6. It can be seen that the RQ values of PFOA, PFHxA, and PFNA at different points in the Fuyang River are all less than 0.01, indicating a relatively low risk. The RQ value of PFOS in the surface water at points S1, S2, and S3 is less than 0.01, indicating a relatively low risk. The RQ value of PFOS in the surface water at the S4 and S5 points is greater than 0.01 but less than 0.1, indicating low risk. Overall, the concentration of PFASs in the Fuyang River does not pose ecological risks to aquatic organisms (fish).

Due to the lack of relevant toxicological data [42], this paper only evaluated the health risks of seven PFASs, as shown in Figure 7. As shown in Figure 7a, the HQ values of PFASs (0.0003–0.1846) are all below 0.2 in high exposure background scenarios, with the highest HQ value of PFHxS (0.1846). We found that S1 and S2 serve as drinking water sources in Handan, and the risks posed by each PFAS to human health can be negligible. As shown in Figure 7b, in males, the HQ_mix value of PFASs in the 3–6-year-old group is 0.2471, ranging from 0.2 to 1. Among females, the HQ_mix of PFASs in the age groups of 3–6 (0.2601), 20–24 (0.2346), 25–59 (0.2162), and >60 (0.2123) ranges from 0.2 to 1. PFASs pose uncertain risks to the health of the five groups mentioned above, while the health risks to other groups can be ignored. Overall, the populations aged 3–6 (0.2471–0.2601), 20–24 (0.1878–0.2346), and >60 (0.1881–0.2123) have higher HQ_mix values, indicating a relatively high susceptibility to PFASs. This is because individuals aged 3–6 have a lower body mass. However, under the same daily water consumption conditions, the body weight of the age groups of 20–24 and >60 is lower than that of other age groups. For different PFAS monomers, the HQ value of females (0.0003–0.1846) is slightly higher than that of males (0.0003–0.1753), but there is no significant difference. For various PFASs, there is a trend in all age groups where the HQ_mix values of females (0.1572–0.2601) are higher than those of males (0.1409–0.2471). This indicates that compared to males, the cumulative toxicity of PFASs poses a greater risk to females, and their potential health risks cannot be ignored. This is consistent with the conclusion of reference [77].

The methods used for risk assessment and health risk assessment above are relatively simple. And due to data scarcity, it was not possible to evaluate all PFASs, nor did it consider the potential compound risks that all PFASs may bring. From the results of this paper, it can be seen that the overall health risk of the Fuyang River is relatively low. However, the biological accumulation caused by long-term intake of PFASs in drinking water still poses significant health risks to local residents [42].

4. Conclusions

This study detected the concentration of PFASs in the surface water of the Fuyang River and analyzed their occurrence status. At the same time, the sources of such substances were analyzed, and their potential risks were analyzed. Thus, the following conclusions can be drawn:

(1)

There are 10 types of PFASs higher than the limit of quantitation in the surface water of the Fuyang River, with at least 7 types at each point. The surface water $\rho$(∑PFASs) ranges from 13.797 to 22.880 $\mathrm{ng}·{\mathrm{L}}^{-1}$. PFCAs are mainly composed of PFOA and PFHxA. PFSAs are mainly based on PFOS. The main component in the surface water is PFOS (mass fraction of 59.40%). The main pollutants in the surface water are long-chain PFASs. The short-chain substitution effect is not significant. The surface water PFASs of the Fuyang River are at a low-concentration pollution level.

(2)

The overall PFASs in the downstream of the Handan section of the Fuyang River are relatively high, and the PFASs show a gradually increasing trend in the downstream. Spearman correlation analysis suggests that the PFASs in the Fuyang River may have the same source. By combining the ratios of PFHxA/PFOA and PFOA/PFNA, it can be concluded that the main sources of PFASs in the Fuyang River are industrial activities and rainfall inputs around the river. Through principal component analysis, it was found that the main sources of PFASs in the Fuyang River are leather, textile manufacturing, fluorinated compound production, and electroplating metal industries.

(3)

The RQ values of four PFASs in the Fuyang River are all less than 0.1, indicating that the concentration of PFASs has not yet reached the level that may pose ecological risks. Similarly, under a high exposure background, the HQ values of seven PFASs in the Fuyang River did not reach the threshold for health risk assessment, indicating that the PFASs in the Fuyang River are at a low health risk level. However, the age groups of 3–6, 20–24, and over 60 years old are more susceptible to PFASs, and the cumulative toxicity of PFASs poses a greater risk to females.

This study has to some extent filled the gap in the investigation of PFAS pollution in the Fuyang River (Handan section). It provides further data support for water pollution assessment. It provides a data basis for further exploration of the cumulative load transported by the river’s flow along its course.