Abstract

The potential negative effects of perfluoroalkyl substances (PFASs) discharged into aquatic environments are drawing increasing attention. However, little research has been undertaken on PFASs in wastewater from electroplating industrial parks. In this study, the concentration profiles and geographical distribution of 11 PFASs were analyzed in water samples collected from different production workshops and an artificial landscaped lake. The total concentrations of PFASs (Σ11PFASs) at various points in the production drainage system range from 229.5 to 5410.6 ng/L, and are mainly contributed by nickel plating, pickling, and the cyanide bright silver plating procedure, which correspond to cyanide-containing and acid-alkali wastewater conditioning tanks. Wastewater treatment by oxidation and precipitation removed 52.6% and 20% of PFASs, respectively. Σ11PFASs in effluents is about 538 ng/L, which consists of perfluorooctanoic acid (PFOA, 430.5 ng/L), followed by perfluorooctane sulfonate (PFOS, 35.27 ng/L), perfluorohexane sulfonate (PFHxS, 28.05 ng/L), and perfluorohexanoic acid (PFHxA, 18.3 ng/L). Principal component analysis suggests that the Σ11PFASs in electroplating wastewater is very high and short-chain (C4–C8) PFASs have high detection and contribution rates. As a result, much attention should be paid to the increase in short-chain substitution effects and pollution around the factory area.

INTRODUCTION

Perfluoroalkyl substances (PFASs) are artificial organofluorine chemicals in which all hydrogen atoms on a carbon chain are replaced by fluorine atoms, resulting in thermal and chemical inertness (Yeung et al. 2017; Groffen et al. 2018). Because of their stable nature and hydrophobic characteristics, they are widely used in various industries and consumer products, such as surface protectors in carpets, lubricants, pesticides, surfactants, fire extinguishing foam, textile coatings, non-stick coatings, food packaging, and cosmetics (Borg et al. 2013; Hanssen et al. 2013; Rahman et al. 2014). PFASs are a group of emerging and ubiquitous organic pollutants that have potential toxicity to humans and organisms in the environment. In particular, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been repeatedly recorded at higher concentrations in urban wastewater and are detected in almost all environmental media, including sediment, landfill leachates, surface water, marine water, and even drinking water (Stahl et al. 2011; Lu et al. 2015; Wluka et al. 2017). For instance, PFOA was detected at relatively high concentrations of 500 ng/L near fluorochemical manufacturing facilities in the Tennessee River and 520 ng/L in drinking water in Germany (Veronika et al. 2015; Pan et al. 2016; He et al. 2018). Zhou et al. (2017) analyzed 10 WWTPs effluents from Wuhan, China, and found that the short-chain homologs like perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) had become the dominant PFCs in wastewater and surface water samples. Besides, in the influent and effluent of 10 WWTPs from the USA, PFOS concentrations were in the range of 1.1–130 ng/L, while PFOA concentrations varied from 2.5 to 97 ng/L (Chen et al. 2016).

Although PFASs are widely detected in environmental media, including wastewater treatment plants (WWTPs), rivers, and lakes, there are few studies on the pollution level and characteristics of PFASs in chemical industrial parks, especially for characteristic industrial wastewater. The literature covers the presence of PFASs in the environment to key industry emissions and concerns about impacts on the surrounding environment and human health. Electroplating, an important processing industry in developed areas of China, uses a fluorine-containing surfactant in the process of wax removal before electroplating in chemical and electrolytic deoiling processes. Most treatment of electroplating wastewater is for heavy metal ions, so the effectiveness of persistent pollutant removal is not clear.

In view of the potential toxicity of PFASs, this study assesses the concentration characteristics of wastewater produced from various sections and treatment units in order to understand the environmental fate and migration of PFASs in aqueous solution, as well as to provide data for environmental management and environmental risk assessments.

MATERIALS AND METHODS

Chemicals and reagents

The main chemicals include: methanol (GR), methyl tert butyl ether (MTBE, 99%), tetrabutylammonium hydrogen sulfate (TBA, 97%), ammonium acetate (chromatographic purity), glacial acetic acid (GR, >99.8%) and ammonia (GR, 50% v/v).

The main reagents include perfluorobutyric acid (PFBA), perfluorovalerate (PFPeA), perfluoroheptanoic acid (PFHpA), perfluoroproxic acid (PFOA), perfluorononylic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoate (PFDoDA) and perfluorooctyl sulfonic acid (PFOS), perfluorohexanic acid (PFHxA), perfluorohexanoic acid (PFUnDA), and perfluorotridecanoic acid (PFTrDA), perfluorobutyl sulfonic acid (PFBS) and perfluorohexyl sulfonic acid (PFHxS), perfluorooctyl sulfonamide (FOSA), quantitative mixed standard PFAC-MXB, internal standard 13C4-PFOS, internal standard 13C4-PFOA, internal standard 13C4-PFBA, and internal standard 13C2-PFDoDA.

Deionized water was provided by the Milli-Q Advantage A 10 system (USA, Millipore) at a resistivity of 18.2 M · Ω. The filter membrane (0.45 µm, 47 mm i.d. glass fibre filter) was purchased from Sartorius Stedim Biotech company. The Oasis WAX 6 cc (150 mg) pre-processing column was purchased from Waters company. The chromatographic system is the UltiMate 3,000 liquid chromatograph, with UltiMate 3,000 automatic injector and Chromeleon 6.70 chromatography workstation (Dionex, USA); analysis column is Acclaim 120 C18 column (4.6 × 150 mm, 5 µm, Dionex, USA). The mass spectrometry system was a API 3200 three heavy four stage tandem mass spectrometry system (AB, USA), equipped with an electrospray ionization (ESI) ion source and Analyst 1.4.1 workstation.

Water samples collection

A total of 32 water samples include 20 samples in production workshops, three samples in treatment units and nine samples from a landscape lake near the factory were collected in an electroplating industrial park (Guangzhou, China). In this factory area, the 1st workshop was old premises on a smaller scale that used electrolytic degreasing as pretreatment, whereas the 5th workshop was a new large scale factory building using chemical degreasing methods. Each workshop has collection pools for various types of wastewaters, such as acid-base pools, copper-plated pickling pools, etc. After the wastewaters flowed through the regulating tanks, the electroplating wastewater was treated by physicochemical method include three processes which are alkali + oxidant (calcium hypochlorite), adding PAC and PAM, severally. All the wastewater samples in the three processes were also collected by using polyethylene sample bottles and then stored at 4 °C until samples were processed and analyzed. The specific collection information is presented in Figure 1 and Table 1.

Table 1

Information of sampling point

Number Position Number Position 
1st workshop (Ni+11 Nickel regulating pool (surface) 
1st workshop (Cu2+12 Copper regulating pool (surface) 
1st workshop (mixture) 13 Mixed regulation pool (surface) 
1st workshop ((CN)214 Cyanide regulating pool (surface) 
1st workshop (acid-base) 15 Acid-base regulating pool (surface) 
5th workshop (Ni+16 Nickel regulating pool (bottom) 
5th workshop (Cu2+17 Copper regulating pool (bottom) 
5th workshop (mixture) 18 Mixed regulation pool (bottom) 
5th workshop ((CN)219 Cyanide regulating pool (bottom) 
10 5th workshop (acid-base) 20 Acid-base regulating pool (bottom) 
Control point (underground water: 15 km in the southwest part of the factory) Landscape lake, Southeast of factory area, 15 ± 1 km. 
Landscape lake, southeast 16 km Landscape lake, southeast 16 km 
Landscape lake, southeast 20 km Landscape lake, southeast 23 km 
Landscape lake, southeast 22 km Landscape lake, southeast 28 km 
Landscape lake, southeast 27 km 21 Oxidation pool 
22 PAC pool 23 PAM pool 
Number Position Number Position 
1st workshop (Ni+11 Nickel regulating pool (surface) 
1st workshop (Cu2+12 Copper regulating pool (surface) 
1st workshop (mixture) 13 Mixed regulation pool (surface) 
1st workshop ((CN)214 Cyanide regulating pool (surface) 
1st workshop (acid-base) 15 Acid-base regulating pool (surface) 
5th workshop (Ni+16 Nickel regulating pool (bottom) 
5th workshop (Cu2+17 Copper regulating pool (bottom) 
5th workshop (mixture) 18 Mixed regulation pool (bottom) 
5th workshop ((CN)219 Cyanide regulating pool (bottom) 
10 5th workshop (acid-base) 20 Acid-base regulating pool (bottom) 
Control point (underground water: 15 km in the southwest part of the factory) Landscape lake, Southeast of factory area, 15 ± 1 km. 
Landscape lake, southeast 16 km Landscape lake, southeast 16 km 
Landscape lake, southeast 20 km Landscape lake, southeast 23 km 
Landscape lake, southeast 22 km Landscape lake, southeast 28 km 
Landscape lake, southeast 27 km 21 Oxidation pool 
22 PAC pool 23 PAM pool 
Figure 1

Production process flow chart of electroplating park.

Figure 1

Production process flow chart of electroplating park.

Sample treatment

The supernatant was filtered through 0.45 μm glass fiber membrane to remove suspended particulates firstly, 2 ng 13C4-PFOA and 13C4-PFOS standard samples were added to 200 mL of water samples evenly aimed to enrich and purify by WAX columella, which had been activated via 4 mL, 0.1% of NH3·H2O-CH3OH, 4 mL of CH3OH solution and 8 mL of ultra-pure water. The flow rate was controlled at about 1 drop/second during sampling, and the WAX column was washed sequentially with 4 mL of 25 mmol/L acetate buffer and 4 mL of water. The samples were then processed in subsequent steps such as elution with methanol and nitrogen volume and analyzed after being vortexed and centrifuged. Afterwards, the instrumental separation and quantification of PFASs was performed using high performance liquid chromatography (HPLC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS), which followed previously developed methods by Shi et al. (2015).

Instrumental analysis

The column of C18 reversed phase chromatography was selected to analyse which was washed by using methanol and 50 mM acetic acid as mobile phase and gradient elution. Specific chromatographic conditions include that the chromatography column was an Acclaim 120 C18 (4.6 × 150 mm, 5 m), mobile phase A was methanol, mobile phase B was 50 mM ammonium acetate solution, the sample volume was 10 µL with the 1 mL/min of flow rate. Otherwise, the optimized mass spectrometry conditions were as follows: 0.24 MPa of air curtain gas, 0.021 MPa of collision gas, 2,000 V of ion spray voltage at 400 °C temperature.

Quality assurance and quality control (QA/QC)

In accordance with the above sample pretreatment and analytical method as well as the chromatography-mass spectrometry conditions, the water samples were taken to investigate the recovery and reproducibility of the method. The two internal standards including 2 ng 13C4-PFOA and 2 ng 13C4-PFOS mixed with other standard solution were added to the samples before extraction. The recoveries and reproducibility of PFASs in water samples are shown in Table 2. The coefficients of determination (r2) of calibration curves for target analytes were all higher than 0.995. The limit of detection (LOD) was defined as the concentration that yielded a signal-to-noise (S/N) ratio of 3, while the limit of quantification (LOQ) was defined as the concentration that yielded a S/N ratio of 10.

Table 2

The recovery rate of PFASs in water and sediment

PFASs Water samples
 
Recovery rate
 
Relative standard deviation
 
2 ppb 20 ppb 2 ppb 20 ppb 
PFBA 104% 102% 6% 6% 
PFPeA 121% 120% 1% 7% 
PFHxA 94% 115% 1% 5% 
PFHpA 108% 121% 1% 4% 
PFOA 98% 114% 4% 6% 
PFNA 103% 118% 2% 4% 
PFDA 107% 109% 1% 11% 
PFUdA 127% 117% 4% 15% 
PFBS 90% 104% 1% 6% 
PFHxS 106% 113% 2% 1% 
PFOS 112% 100% 6% 4% 
PFASs Water samples
 
Recovery rate
 
Relative standard deviation
 
2 ppb 20 ppb 2 ppb 20 ppb 
PFBA 104% 102% 6% 6% 
PFPeA 121% 120% 1% 7% 
PFHxA 94% 115% 1% 5% 
PFHpA 108% 121% 1% 4% 
PFOA 98% 114% 4% 6% 
PFNA 103% 118% 2% 4% 
PFDA 107% 109% 1% 11% 
PFUdA 127% 117% 4% 15% 
PFBS 90% 104% 1% 6% 
PFHxS 106% 113% 2% 1% 
PFOS 112% 100% 6% 4% 

RESULTS AND DISCUSSION

Spatial distribution and composition profiles of PFASs

The electroplating industrial plant wastewater was divided into two workspaces that include the 1st workshop and 5th workshop, which were numbered No. 1–5 and No. 5–10, respectively. Test results showed that the total concentrations of 11 PFASs (∑11PFASs) ranged from 7.26 ng/L to 6,709.41 ng/L, and the average value was 780 ng/L. The detection rate of all 11 PFASs in 10 sampling sites was as high as 93%, each substance occupies proportion is shown in Figure 2. It can be seen that PFHxS, PFHxA, PFBA and PFBS are the substances with the highest content in the 1st workshop that used electrolytic degreasing technique. The results of sampling sites 6–10 reveal that the dominant substances were PFOA, PFHxA and PFOS. Obviously, PFASs in regulation pools is relatively similar, that mainly based on PFOA and PFOS, which accounted for 92.8% and 94.4% of the total PFASs of the surface and the bottom of tanks, respectively.

Figure 2

Pollution level of each component of PFASs from 20 sampling points.

Figure 2

Pollution level of each component of PFASs from 20 sampling points.

The concentration distributions of each PFAS in different process regulating pools' samples are shown in Figure 3. The PFASs concentration in the five collecting areas exceeded 800 ng/L, reaching 6,709, 1,230, 5,410, 1,837 and 8,129 ng/L, which was in the fifth acid-alkali wastewater collecting pool, nickel-containing regulating pool and acid-alkali regulating pool, severally.

Figure 3

Pollution level of each component of PFASs in the park from the 1st and 5th workshops. The composition of the 11 types of PFASs pollutants at each sampling point is shown above.

Figure 3

Pollution level of each component of PFASs in the park from the 1st and 5th workshops. The composition of the 11 types of PFASs pollutants at each sampling point is shown above.

According to the different production processes, the PFASs concentration varies greatly. The lowest total concentrations of the Σ11PFASs were in the 1st workshop, where the means of Σ11PFASs were 83 ng/L. For the production processes, the nickel-containing conditioning tool and the acid-base conditioning tool are the two accumulation areas with the highest PFASs content. The concentration means of Σ11PFASs in regulating pools from sample sites 11–20 ranged from 1.3–1,674 ng/L, among which the highest concentration mean of Σ11PFASs was for the acid-base pool (mean 6,770 ng/L), followed by the nickel pool (mean 1,533 ng/L), the copper pool (mean 700 ng/L), the cyanide pool (mean 347 ng/L) and the mixed pool (mean 227 ng/L).

Furthermore, wastewater samples from the surface and bottom of five large regulating ponds were also collected and analyzed (Figure 4) in order to investigate the partition behavior of PFASs in the dissolved water phase. The results show that there are obvious differences in pollution concentration between the bottom of the pond and the surface of the pond.

Figure 4

11PFASs concentration in the surface and bottom from different regulating pool units. The water samples in the five process regulation tanks including the surface and the bottom of these pools were collected and detected, where the light gray data represent the pool surface. The top two sector areas are the proportions of the 11 components of the PFASs in the pool bottom and surface pools, respectively.

Figure 4

11PFASs concentration in the surface and bottom from different regulating pool units. The water samples in the five process regulation tanks including the surface and the bottom of these pools were collected and detected, where the light gray data represent the pool surface. The top two sector areas are the proportions of the 11 components of the PFASs in the pool bottom and surface pools, respectively.

The wastewater from each production process was gathered back to the regulating pool. ∑11PFASs in the surface (0.1 m below the surface of the water) was 7,991 ng/L, lower than the bottom (2.4 m below the surface of the water), of 11,166 ng/L. PFOA accounts for the highest proportion of ∑11PFASs in both the surface (86.6%) and bottom (88%) of the regulating pool, and its proportion in the 1st workshop and 5th workshop was relatively high, at approximately 56% and 24%. Such ultra-high concentrations of PFOA may be attributed to the convergence of the 5th workshop with the drainage from other workshops. In addition, this section needs many cleaning agents, flux, and lubricants, leading to a large volume of such pollutants. PFASs in the regulating pool shows a tendency for the concentration of the bottom to be higher than the supernatant. And after mixing the production process wastewater of each regulation pool, the concentration of PFASs was evenly distributed with a high level.

The ∑11PFASs concentrations were generally higher than those of other industrial wastewaters. In addition to PFOA and PFOS, PFHxS, PFHpA and PFBA accounted for the highest proportion of PFASs in both the production workshop drainage and the wastewater regulating pool, which indicates that short-chain PFASs have become the main constituent of PFASs in the study area.

Evaluation and distribution on PFASs remove

The wastewater was mixed and precipitated in the regulation basin, then entered into the oxidation tank and coagulatory settler. Figure 5 depicts the change of ∑11PFASs in the different treatment units. The results show that the concentrations of PFASs in the oxidation, PAC and PAM sedimentation tanks were 908.2, 683.9 and 537.6 ng/L respectively, which indicated that the oxidant has a positive removal effect for PFASs, with the opposite side being the coagulants have hardly played a role.

Figure 5

Degradation on PFASs in different processing units. PFOA was used as an example to describe the process of oxidation and precipitation.

Figure 5

Degradation on PFASs in different processing units. PFOA was used as an example to describe the process of oxidation and precipitation.

Different from other related studies on PFASs removal in the laboratory, in this study, a large number of calcium hypochlorite oxidizers were added to pretreat various pollutants in the actual treatment process to track the PFASs change. All 11 PFASs removed in the three treatment process ranged from 22% to 100% (Figure 6). Among these the highest removal efficiency was PFUdA (100%, C11), followed by PFOA (74.3%, C8), PFOS (71.2%, C8), PFHpA (67.6%, C7), PFDA (67.2%, C10), PFNA (61.8%, C9), PFBS (57.3%, C7), PFBA (55.6%, C4), PFPeA (40%, C5), PFHxA (35%, C6) and PFHxS (21.9%, C6). Obviously, the long-chain (>C8) PFASs have a higher removal rate; however, the short-chain PFASs where there are fewer than eight carbon atoms were hard to degrade. These PFASs were the main residual pollutants in the dissolved water phase as the high energy of the C-F covalent bonds make PFASs thermally and chemically stable and resistant to biodegradation. Similar to the other related research results, the advanced oxidation technologies (AOPs) have a certain removal effect on PFASs, while the conventional physical pretreatment process achieved little in the removal of such micro pollutants (Zhang et al. 2016).

Figure 6

11PFASs removal efficiencies in different processing units.

Figure 6

11PFASs removal efficiencies in different processing units.

Distribution on surface waters around factory

The wastewater from the workshop drainage was mixed with the domestic wastewater of the plant and incorporated into the municipal sewage pipeline after the above treatments. The approximate location and test results of the sampling are shown below.

Figure 7 shows that although the level of groundwater contamination is low, it is mainly composed of PFOA and PFOS. Previous studies have reported that PFASs in groundwater may come mainly from domestic sewage. Atmospheric deposition studies on pollution pathways and estimates of PFOS release in China have found that industrial wastewater is the dominant pollution source of PFOS in groundwater, contributing 50.5% (Ding et al. 2018). In this study, pollution of surface lakes is evident, with average ∑11PFASs ranging between 13.2 ng/L and 34.6 ng/L. The ∑11PFASs in the lake were slightly higher than elsewhere. As the artificial lake is closer to the plant area, the higher PFAS pollution levels in the lake may be due to an effect of the electroplating industrial park.

Figure 7

PFASs distribution in the lake around the factory area. The histogram represents the distance from the sampling point to the factory while the van diagram represents the pollution concentration at the sampled sites.

Figure 7

PFASs distribution in the lake around the factory area. The histogram represents the distance from the sampling point to the factory while the van diagram represents the pollution concentration at the sampled sites.

Discussion on PFASs pollution results

Previous epidemiologic work has shown that the predominant PFASs in each wastewater dissolved phase of the electroplating park are PFOA, PFOS, PFHxS, and PFHxA. Short-chain PFASs are becoming major pollutants in the water phase, as C4 and C7 PFASs are replacing C8 and greater chain-length homologues in most processes. Findings of studies on PFASs concentrations in oceans, rivers, groundwater, and sewage treatment plants can be summarized as follows:

By comparing the water pollution status in different environmental media and regions (Table 3), it clearly indicates that pollution of the ocean and groundwater is relatively negligible, whereas it is of greater concern in the surface water system. The results of most surface water studies show that the concentration of PFASs is much lower than that of the wastewater from the electroplating park. In particular, PFBA and PFBS appear more frequently on the list, such as in Sweden, which is accompanied by a higher level of existence. As one of the short-chain PFASs, PFBS is often used as an alternative for the long-chain PFOS, which, with the mass production and broad applications of PFBS, could contribute to the relatively high concentrations in the water environment. Additionally, the Kd value (the equilibrium dissociation constant) of PFBS is lower than that of PFOS and PFOA, which makes PFBS more mobile in aqueous solution, and leads to the higher concentration of PFBS in groundwater as a result.

Table 3

Concentration comparison of PFASs in the typical region

Environmental medium Sampling area Main compounds and their concentration range (ng/L) References 
Seas and oceans Western Pacific Ocean PFOA: 0.136 ∼ 0.142; PFOS: 0.054 ∼ 0.078 Yamashita et al. (2005)  
North Atlantic Ocean PFOA: 0.160 ∼ 0.338; PFOS: 8.60 × 10−3 ∼ 0.036 Yamashita et al. (2005)  
South China Sea PFOA: 30.80 × 10−3 ∼ 1.15; PFOS: 17.30 × 10−3 ∼ 1.64 Kwok et al. (2015)  
Rivers The River Rhine (upstream) PFHxS: <5.10 ∼ 14.50; PFPeA: <0.66 ∼ 9.99 Möller et al. (2010)  
The River Rhine (downstream) PFBA: 75.5 ∼ 188; PFBS: 15 ∼ 118 Möller et al. (2010)  
The Yangtze River (estuary) PFOA: 0.98 ∼ 6.9; PFHxA: 0.2 ∼ 1.4 Zhao et al. (2017)  
Groundwater Tokyo (Japan) PFOS: 0.28 ∼ 133; PFNA: 0.1 ∼ 94 Murakami et al. (2009)  
Mainland France PFOS: 4 ∼ 50; PFPeA: 5 ∼ 40 Boiteux et al. (2012)  
Overseas France PFPeA: 0.27 ∼ 213; PFHxA: 0.1 ∼ 158 Munoz et al. (2017)  
Effluents of wastewater treatment plants Henriksdal WWTP, Sweden PFBA: 5.5 ∼ 12.3; PFHxA: 5.5 ∼ 7.3 Eriksson et al. (2017)  
The Umeå WWTP, Sweden PFBA: <3.4 ∼ 30.1; PFHxA: 6.8 ∼ 16.8 Eriksson et al. (2017)  
The Gässlösa WWTP, Sweden PFBA: <3.4 ∼ 8.2; PFHxA: 3.2 ∼ 5.0 Eriksson et al. (2017)  
WWTP in Wuhan, China PFBA: 7.4 ∼ 1,870; PFHxA: 3.7 ∼ 367; PFOA: 4.6 ∼ 270; PFDA: <0.5 ∼ 5.2; PFHxS: 1.04 ∼ 92.8; PFOS:1.1 ∼ 1,072 Zhou et al. (2017)  
Fluorochemical manufacturing facility The north of France 6:2FTAB: 4 × 106 ∼ 45.5 × 106; M4: 8.6 × 105 ∼ 5.7 × 106; 6:2FTSA: 4.4 × 105 ∼ 4.4 × 106 Dauchy et al. (2017)  
Fluorochemical industrial park The south of China PFOA: 64.3 ∼ 1,503; PFHxA: 28.1 ∼ 230 Wei et al. (2013)  
Electroplating factory Guangzhou, China PFHxA: 1.67 ∼ 179.2; PFHpA: 0 ∼ 784; PFOA: 206 ∼ 2.5 × 104; PFNA: 2.4 ∼ 714.5; PFOS: 87 ∼ 259; PFDA: 2.95–364.5 This study 
Environmental medium Sampling area Main compounds and their concentration range (ng/L) References 
Seas and oceans Western Pacific Ocean PFOA: 0.136 ∼ 0.142; PFOS: 0.054 ∼ 0.078 Yamashita et al. (2005)  
North Atlantic Ocean PFOA: 0.160 ∼ 0.338; PFOS: 8.60 × 10−3 ∼ 0.036 Yamashita et al. (2005)  
South China Sea PFOA: 30.80 × 10−3 ∼ 1.15; PFOS: 17.30 × 10−3 ∼ 1.64 Kwok et al. (2015)  
Rivers The River Rhine (upstream) PFHxS: <5.10 ∼ 14.50; PFPeA: <0.66 ∼ 9.99 Möller et al. (2010)  
The River Rhine (downstream) PFBA: 75.5 ∼ 188; PFBS: 15 ∼ 118 Möller et al. (2010)  
The Yangtze River (estuary) PFOA: 0.98 ∼ 6.9; PFHxA: 0.2 ∼ 1.4 Zhao et al. (2017)  
Groundwater Tokyo (Japan) PFOS: 0.28 ∼ 133; PFNA: 0.1 ∼ 94 Murakami et al. (2009)  
Mainland France PFOS: 4 ∼ 50; PFPeA: 5 ∼ 40 Boiteux et al. (2012)  
Overseas France PFPeA: 0.27 ∼ 213; PFHxA: 0.1 ∼ 158 Munoz et al. (2017)  
Effluents of wastewater treatment plants Henriksdal WWTP, Sweden PFBA: 5.5 ∼ 12.3; PFHxA: 5.5 ∼ 7.3 Eriksson et al. (2017)  
The Umeå WWTP, Sweden PFBA: <3.4 ∼ 30.1; PFHxA: 6.8 ∼ 16.8 Eriksson et al. (2017)  
The Gässlösa WWTP, Sweden PFBA: <3.4 ∼ 8.2; PFHxA: 3.2 ∼ 5.0 Eriksson et al. (2017)  
WWTP in Wuhan, China PFBA: 7.4 ∼ 1,870; PFHxA: 3.7 ∼ 367; PFOA: 4.6 ∼ 270; PFDA: <0.5 ∼ 5.2; PFHxS: 1.04 ∼ 92.8; PFOS:1.1 ∼ 1,072 Zhou et al. (2017)  
Fluorochemical manufacturing facility The north of France 6:2FTAB: 4 × 106 ∼ 45.5 × 106; M4: 8.6 × 105 ∼ 5.7 × 106; 6:2FTSA: 4.4 × 105 ∼ 4.4 × 106 Dauchy et al. (2017)  
Fluorochemical industrial park The south of China PFOA: 64.3 ∼ 1,503; PFHxA: 28.1 ∼ 230 Wei et al. (2013)  
Electroplating factory Guangzhou, China PFHxA: 1.67 ∼ 179.2; PFHpA: 0 ∼ 784; PFOA: 206 ∼ 2.5 × 104; PFNA: 2.4 ∼ 714.5; PFOS: 87 ∼ 259; PFDA: 2.95–364.5 This study 

The electroplating factory studied in this study is similar to fluorine chemical production parks, which are the main source of PFASs emissions and have higher concentrations of complex PFASs, especially short-chain homologues, which further highlights the emergence of the short-chain substitution effect in the chemical industry. Given this widespread contamination, concerns have been raised about adverse biological and human health effects related to their potential toxicity. And epidemiological researches have revealed that exposure to PFASs may be associated with biochemical or physiological alterations in human populations (Steenland et al. 2010). Progressively, the US Environmental Protection Agency (USEPA) has set a ‘provisional health advisory’ of 0.4 ppb for PFOA and 0.2 μg/L for PFOS as the safe level in drinking water. Therefore, the PFASs study on electroplating industrial areas aims to highlight the importance of their work regarding the lack of information about these compounds that exists in the world.

CONCLUSION

PFASs were widely detected in workshop production wastewater from electroplating industrial areas in Guangzhou province, China. It was shown that ∑11PFASs exist at high pollution levels in each production process. In terms of the spatial distribution, from high to low, in the acid-base regulating pool > nickel containing regulating pool > copper containing regulating pool > cyanide regulating pool > mixing and regulating pool. Based on the different production stages in the workshop, PFOA, PFOS, PFHxA, and PFHxS are the most abundant pollutants, with concentrations up to 4,565.5 ng/L, 109.4 ng/L, 177 ng/L, and 55.4 ng/L, respectively. The mixed regulating wastewaters were treated in sewage treatment facilities by adding oxidants and coagulants, and the process of oxidation can remove 48.4% of PFASs, whereas the PAC and PAM flocculation settling tanks could remove 12% and 8% of PFASs. Field test results for the landscaped lakes and underground water samples around the factory area reveal that the factory has a potential effect on the concentration of PFASs in the surrounding surface water.

ACKNOWLEDGEMENTS

We gratefully acknowledge the financial support provided by the National Key R & D plan for High-efficiency Utilization Technology and Demonstration of Large Coal Mines and Non-ferrous Mines (No. 2018YFC0406403).

REFERENCES

REFERENCES
Boiteux
V.
,
Dauchy
X.
,
Rosin
C.
&
Munoz
J. F.
2012
National screening study on 10 perfluorinated compounds in raw and treated tap water in France
.
Archives of Environmental Contamination & Toxicology
63
(
1
),
1
12
.
Borg
D.
,
Lund
B. O.
,
Lindquist
N. G.
&
Håkansson
H.
2013
Cumulative health risk assessment of 17 perfluoroalkylated and polyfluoroalkylated substances (PFASs) in the Swedish population
.
Environment International
59
(
59C
),
112
123
.
Chen
H.
,
Reinhard
M.
,
Nguyen
V. T.
&
Gin
K. Y.
2016
Reversible and irreversible sorption of perfluorinated compounds (PFCs) by sediments of an urban reservoir
.
Chemosphere
144
,
1747
1753
.
Dauchy
X.
,
Boiteux
V.
,
Bach
C.
,
Colin
A.
,
Hemard
J.
,
Rosin
C.
&
Munoz
J. F.
2017
Mass flows and fate of per- and polyfluoroalkyl substances (PFASs) in the wastewater treatment plant of a fluorochemical manufacturing facility
.
Science of the Total Environment
576
,
549
558
.
Ding
G.
,
Xue
H.
,
Zhang
J.
,
Cui
F.
&
He
X.
2018
Occurrence and distribution of perfluoroalkyl substances (PFASs) in sediments of the Dalian Bay, China
.
Marine Pollution Bulletin
127
,
285
288
.
Eriksson
U.
,
Haglund
P.
&
Kärrman
A.
2017
Contribution of precursor compounds to the release of per-and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs)
.
Journal of Environmental Sciences 2017
61
(
11
),
80
90
.
Groffen
T.
,
Wepener
V.
,
Malherbe
W.
&
Bervoets
L.
2018
Distribution of perfluorinated compounds (PFASs) in the aquatic environment of the industrially polluted Vaal River, South Africa
.
Science of the Total Environment
627
,
1334
1344
.
Hanssen
L.
,
Dudarev
A. A.
,
Huber
S.
,
Nieboer
E.
&
Sandanger
T. M.
2013
Partition of perfluoroalkyl substances (PFASs) in whole blood and plasma, assessed in maternal and umbilical cord samples from inhabitants of Arctic Russia and Uzbekistan
.
Science of the Total Environment
447
(
1
),
430
437
.
He
X.
,
Ding
L.
,
Su
W.
,
Ma
H.
,
Huang
H.
&
Wang
Y.
2018
Distribution of endotoxins in full scale pharmaceutical wastewater treatment plants and its relationship with microbial community structure
.
Water Science & Technology
77
(
10
),
2397
.
Kwok
K. Y.
,
Wang
X. H.
,
Ya
M.
,
Li
Y.
,
Zhang
X. H.
,
Lam
J. C.
&
Lam
P. K.
2015
Occurrence and distribution of conventional and new classes of per- and polyfluoroalkyl substances (PFASs) in the South China Sea
.
Journal of Hazardous Materials
285
,
389
397
.
Lu
Z.
,
Song
L.
,
Zhao
Z.
,
Ma
Y.
,
Wang
J.
,
Yang
H.
,
Ma
H.
&
Cai
M.
2015
Occurrence and trends in concentrations of perfluoroalkyl substances (PFASs) in surface waters of eastern China
.
Chemosphere
119
,
820
827
.
Möller
A.
,
Ahrens
L.
,
Surm
R.
,
Westerveld
J.
,
Vander
W. F.
&
Ebinghaus
R.
2010
Distribution and sources of polyfluoroalkyl substances (PFAS) in the River Rhine watershed
.
Environmental Pollution
158
(
10
),
3243
3250
.
Munoz
G.
,
Labadie
P.
,
Botta
F.
,
Lestremau
F.
,
Lopez
B.
&
Geneste
E.
2017
Occurrence survey and spatial distribution of perfluoroalkyl and polyfluoroalkyl surfactants in groundwater, surface water, and sediments from tropical environments
.
Science of the Total Environment
243
,
607
608
.
Murakami
M.
,
Kuroda
K.
,
Sato
N.
,
Fukushi
T.
,
Takizawa
S.
&
Takada
H.
2009
Groundwater pollution by perfluorinated surfactants in Tokyo
.
Environmental Science & Technology
43
(
10
),
3480
3486
.
Rahman
M. F.
,
Peldszus
S.
&
Anderson
W. B.
2014
Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: a review
.
Water Research
50
(
1
),
318
340
.
Shi
Y.
,
Vestergren
R.
,
Xu
L.
,
Song
X.
,
Niu
X.
,
Zhang
C.
&
Cai
Y.
2015
Characterizing direct emissions of perfluoroalkyl substances from ongoing fluoropolymer production sources: a spatial trend study of Xiaoqing river, China
.
Environmental Pollution
206
(
1
),
104
112
.
Stahl
T.
,
Riebe
R. A.
,
Falk
S.
,
Failing
K.
&
Brunn
H.
2011
Long-term lysimeter experiment to investigate the leaching of perfluoroalkyl substances (PFASs) and the carry-over from soil to plants: results of a pilot study
.
Journal of Agricultural & Food Chemistry
61
(
8
),
1784
1793
.
Steenland
K.
,
Fletcher
T.
&
Savitz
D. A.
2010
Epidemiologic evidence on the health effects of perfluorooctanoic acid (PFOA)
.
Environmental Health Perspectives
118
(
8
),
1100
1108
.
Veronika
S.
,
Darina
L.
,
Jan
P.
,
Monika
T.
,
Jana
H.
&
Jana
P.
2015
Perfluoroalkyl substances (PFASs) and other halogenated compounds in fish from the upper Labe river basin
.
Chemosphere
129
,
170
178
.
Wei
M. C.
,
Zhong
W. J.
&
Zhao
L. X.
2013
Distribution and profile of perfluorinated compounds in the environment around a fluorine chemistry industrial park in South China
.
Acta Scientiae Circumstantiae
33
(
7
),
1989
1995
.
Wluka
A. K.
,
Coenen
L.
&
Schwarzbauer
J.
2017
Screening of organic pollutants in urban wastewater treatment plants and corresponding receiving waters
.
Water Science & Technology
76
(
3–4
),
832
846
.
Yamashita
N.
,
Kannan
K.
,
Taniyasu
S.
,
Horii
Y.
,
Petrick
G.
&
Gamo
T.
2005
A global survey of perfluorinated acids in oceans
.
Marine Pollution Bulletin
51
(
8
),
658
668
.
Yeung
W. Y.
,
Dassuncao
C.
,
Mabury
S. A.
,
Sunderland
E. M.
,
Zhang
X.
&
Lohmann
R.
2017
Vertical profiles, sources and transport of pfass in the Arctic ocean
.
Environmental Science & Technology
51
(
12
),
6735
6744
.
Zhang
C. H.
,
Tang
J. W.
,
Peng
C.
&
Jin
M. Y.
2016
Degradation of perfluorinated compounds in wastewater treatment plant effluents by electrochemical oxidation with Nano-ZnO coated electrodes
.
Journal of Molecular Liquids
221
,
1145
1150
.
Zhao
Z.
,
Tang
J.
,
Mi
L.
,
Tian
C.
,
Zhong
G.
&
Zhang
G.
2017
Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary
.
Science of the Total Environment
114
,
599
600
.
Zhou
Z.
,
Hu
Y. N.
,
Shi
Y. L.
&
Cai
Y. Q.
2017
Occurrence and distribution of per- and polyfluoroalkyl substances in waste water and surface water samples in Wuhan
.
Asian Journal of Ecotoxicology
12
(
3
),
425
433
.