•Artificial sweeteners (ASs) were widely detected in pig feed and manure.•ASs can enter soil via application of treated pig manure and urine in huge quantities.•Plants (vegetables) can take up ASs markedly when the ASs concentrations were high in soil.•Dissipation of ASs in field soil were quick with half-lives of several days.Pig farm is an important potential source for artificial sweeteners (ASs) in the environment due to their wide use as additives in pig feed. The objective of this study was to evaluate the fate of typical ASs in pig farm and neighboring farmland. For this purpose, the levels of four typical artificial ASs, i.e. saccharin (SAC), cyclamate (CYC), acesulfame (ACE) and sucralose (SUC), in pig feed and manure from a pig farm and water samples from an on-farm wastewater treatment plant (WWTP) in Tianjin, China were measured and the mass loadings and removal efficiencies were assessed. Moreover, the levels of ASs in different layers of soil and vegetables in neighboring farmland that received manure fertilizers and wastewater from the farm were consecutively monitored for 60–80 days. The SAC, CYC and ACE were widely determined in all kinds of the samples, while SUC was only found in few soil samples. The mass loadings of the ASs in pig feed were estimated up to 311 kg/year for SAC, 59.1 kg/year for CYC, and 17.1 kg/year for ACE, respectively. The fractions of the total mass of ASs excreted via manure were estimated to be 36.0% for SAC, 59.4% for CYC, and 36.7% for ACE as compared to those in pig feed. High removal efficiencies (> 90%) of ASs in the on-farm WWTP was achieved. In greenhouse soils, CYC, SAC, ACE, and SUC were degraded quickly, with half-lives of 4.3–5.9 d, 2.7–4.2 d, 8.4–12.3 d, and 7.3–10.8 d, respectively. Lower levels of ASs were found in deeper soil layer (20–30 cm). The ASs were considerably absorbed by plants when the ASs' concentrations were high in soil. This study presents the first comprehensive overview of ASs fate from a pig farm to the neighboring agricultural ecosystem.Download high-res image (96KB)Download full-size image

•HBCDs were not homogeneously distributed within earthworms.•The concentrations of HBCDs followed the order of gut>body fluid>body wall.•The bioisomerization occurred in all fractions except for the cytosol fraction.•The enantioselectivity in each fraction was the same with that in whole earthworm.In this study, earthworms Eisenia fetida (E. fetida) were exposed to a soil artificially contaminated with individual hexabromocyclododecane (HBCD) diastereoisomers (α-, β- and γ-HBCDs) to investigate the distribution, isomerization and enantiomer selectivity of HBCDs at tissue and subcellular levels. At the tissue level, the concentrations of HBCDs all followed the order of gut>bodyfluid>body wall, which suggested that earthworms accumulated HBCDs mainly via ingesting soil particles. At the subcellular level, the concentrations of HBCDs in an extracellular fraction consisting of granules, tissue fragment, cell membrane and intact cells (fraction A) were higher than those in an intracellular fractions consisting of the microsomal and cytosol (fraction B+C). This confirmed the passive diffusion during the distribution of HBCDs into the intracellular compartment. The distribution proportions of HBCDs varied among different tissue and subcellular fractions, and all changed over time within 14 days. The variable distributions of HBCDs in different fractions were a result of the comprehensive effects of dynamics and thermodynamics processes. The β- and γ-HBCDs were isomerized to α-HBCD in all tissue and subcellular fractions except for fraction C, and the isomerization ratios varied a lot, which seemed to be related to HBCDs residence time. The selective enrichment of (−) α-, (−) β and (−) γ-HBCDs was found in all fractions and this is consistent with that in the whole earthworm. Besides, the extents of enantio-selectivity did not change significantly among different tissue and subcellular fractions.

•HBCDDs could be absorbed by ryegrass from soil but mainly accumulated at roots.•The accumulation of HBCDDs by ryegrass was diastereoisomer- and enantiomer-specific.•The β- and γ-HBCDDs could be transformed to α-HBCDD in ryegrass tissues.•Hydroxy-HBCDDs were for the first time reported as HBCDDs metabolites in plant.This study explored the fate and adverse effects of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDDs) in a soil pot system planted with ryegrass (Lolium perenne L.) using a short-term (8 weeks) experiment. At the end of the experiment, soil urease activity in planted spiked soil increased and catalase activity decreased; while there was no obvious change in sucrase and peroxidase activities. HBCDDs mainly accumulated in the root of ryegrass, with root concentration factors (RCF) in the range of 1.46–4.43 and only a small part was transferred to the stem (SCF: 0.198–0.305) and leaf (LCF: 0.042–0.062). The concentration factors varied for different HBCDD diastereoisomers, being in the order of α- > β- > γ-HBCDD for all tissues, indicating preferential accumulation of α-HBCDD in ryegrass tissues. Moreover, the enantiomeric analysis revealed an enrichment of (+)-α-, (−)-β- and (+)-γ-HBCDD enantiomers in ryegrass tissues. β- and γ-HBCDDs (up to 1.90% and 4.11%, respectively) were transformed to aα-HBCDD in ryegrass, while no isomerization product from α-HBCDD was found. Hydroxylated HBCDDs metabolites, such as monoOHHBCDDs and diOHHBCDDs were found in ryegrass tissues for the first time.Download high-res image (301KB)Download full-size image

•OH and NO2 enhanced naphthalene substituents sorption on low-temperature biochar.•Hydrophobicity and molecular volume determined the sorption on high-temperature biochar.•The ion-pair reaction increased the sorption of anionic 4-nitro-1-naphthol.•pH changed sorption mechanisms in both single-solute and bi-solute systems.The sorption of naphthalene and its hydroxyl-substituted compounds onto two biochars that were produced at different temperatures was studied. The influences of propranolol as a co-solute and solution pH on the sorption were investigated. The sorption capacities of 1-naphthol and 4-nitro-1-naphthol on the biochar with a pyrolytic temperature of 200 °C (BC200) were greater compared to naphthalene. This occurred because the substitution of hydroxyl- and nitro-groups on the aromatic ring enhanced surface adsorption, e.g. hydrogen bond and π-π electron donor-acceptor interaction, while the hydroxyl in 1-naphthalenemethanol did not show the promoting effect. The sorption on the biochar with a pyrolytic temperature of 700 °C (BC700) followed a different sequence of 4-nitro-1-naphthol < 1-naphthalenemethanol < 1-naphthol < naphthalene, which was determined by the hydrophobicity and molecular volume of the sorbates, indicating the dominance of hydrophobic partition and pore-filling in the adsorption on BC700. The co-existence of propranolol promoted the surface hydrophobicity of BC200, which led to an enhancement in the sorption of naphthalene and 1-naphthalenemethanol. Propranolol prohibited the sorption of 1-naphthol by competing for the mutual available surface adsorption sites. The ion-pair reaction between anionic 4-nitro-1-naphthol and cationic propranolol increased the sorption of 4-nitro-1-naphthol. On BC700, propranolol generally prohibited the sorption of the tested sorbates mainly due to competition and pore-blocking. The influence of pH was complicated in both single-solute and bi-solute systems. It simultaneously affected the surface charge of biochars and the form of the tested compounds, which led to the shifting of sorption mechanisms. The finding will shed light on the suitable application of biochar technology.Download high-res image (170KB)Download full-size image

•Molecularly imprinted polymers (MIPs) were synthesized using binary functional monomers.•The prepared MIPs are potential adsorbents for selective removal of PFOA and PFOS.•The adsorption capacities of MIPs for PFOA and PFOS are 6.42 and 6.27 mg/g, respectively.•Selectivity and real application experiments were conducted by the binding of PFOA, PFOS and their analogue.This work describes a novel method for the synthesis of molecularly imprinted polymers (MIPs) using 2-(trifluoromethyl) acrylic acid (TFMAA) and 4-vinyl pyridine (4-Vpy) as binary functional monomers, perfluorooctanoic acid (PFOA) as template, and ethyleneglycol dimethacrylate (EGDMA) as cross-linker in the presence of azobisisobutyronitrile (AIBN). The binary functional monomer MIPs were applied to selective recognition for PFOA and perfluorooctanesulfonic acid (PFOS) from aqueous environment. The MIPs were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and microscopic electrophoresis. Thereafter, the adsorption capacity and selectivity of the synthesized MIPs for PFOA and PFOS were evaluated by batch adsorption experiments. The maximum adsorption capacities of the MIPs for PFOA and PFOS were 6.42 and 6.27 mg/g, respectively. It was also found that the adsorption capacities remained constant with increasing the solution pH in the range of 2.0-5.0, and then decreased when the pH was further increased. Finally, the novel MIPs can be reused after five cycles of adsorption-desorption-adsorption with no significant decrease of removal rate and have an effective performance in selective removal of PFOA and PFOS in real lake water samples. All the results indicate that the binary functional monomer MIPs have great potential to remove PFOA and PFOS in aqueous environment.

•Urinary mPAEs are positively associated with oxidative stress.•Urinary mMP concentrations are negatively related to adiponectin, and positively associated with inflammatory cytokines.•Urinary ∑ DEHP levels are negatively associated with adiponectin in the larger BMI subgroup.•Urinary ∑ DEHP and mEHP levels are positively related to inflammatory cytokines in the larger BMI subgroup.Epidemiologic studies have revealed higher concentrations of the metabolites of phthalic acid esters (mPAEs) in patients with type 2 diabetes. On the other hand, oxidative stress, adiponectin, and inflammatory cytokines play important roles in the pathogenesis of diabetes and its complications. However, little information is known about the association between exposure to PAEs and these physiological parameters. Hence, paired urine and blood samples were collected from a total of 329 volunteers, and 11 main mPAEs and malondialdehyde (MDA), as a biomarker of oxidative stress, were measured in the urine samples. Serum adiponectin and tumor necrosis factor-α (TNF-α), a biomarker of inflammation, were also measured. Multivariable linear regression was used to assess the association between urinary mPAEs and these physiological parameters in the total subjects and subjects stratified by age, sex, and body mass index (BMI) to elucidate their possible interactions. All 11 mPAEs were detected in the urine with detection rates of 42.9%–100% and geometric means of 0.30–54.52 ng/mL (0.44–79.93 μg/g creatinine). The mPAEs were all positively associated with MDA levels. There were significant positive associations between monomethyl phthalate (mMP) and TNF-α, and inverse associations between mMP and adiponectin levels. In the stratified analysis, there were age-, sex-, and BMI–specific differences for these associations. The positive associations between mPAEs and MDA were insignificant in some subgroups, especially in the larger age group. However, in the larger BMI group, summed metabolites of di-(2-ethylhexyl) phthalate (∑ DEHP) and mono(2-ethylhexyl) phthalate were positively associated with TNF-α, and the concentrations of ∑ DEHP were negatively associated with adiponectin. Our findings suggested that PAE exposure is associated with oxidative stress, adiponectin, and inflammatory cytokines in diabetic patients; further studies on toxicology and a comparison with general population are needed.

•Polar functional groups on low-temperature biochar enhanced propranolol sorption.•Humic acid generally inhibited the sorption of organic pollutants onto biochars.•The bridge effect of heavy metals between 4-nitro-1-naphtol and biochars changed its sorption.•The presence of organic pollutants increased the sorption of highly polarizable Ag+ onto biochars.The effects of humic acid (HA) and heavy metals (Cu2+ and Ag+) on the sorption of polar and apolar organic pollutants onto biochars that were produced at temperatures of 200 °C (BC200) and 700 °C (BC700) were studied. Due to the plentiful polar functional groups on BC200, cationic propranolol exhibited higher levels of sorption than naphthalene on BC200 while naphthalene and propranolol showed similar sorption capacities on BC700. HA changed the characteristics of biochars and generally inhibited the sorption of target organic pollutants on biochars; however, enhancement occurred in some cases depending on the pollutants involved and their concentrations, biochars used and the addition sequences and concentrations of HA. On BC200, HA modifications mainly influenced sorption by decreasing its polarity and increasing its aromaticity, while on BC700, the surface area and pore volume greatly decreased due to the pore-blocking effects of HA. Residue dissolved HA in solution may also contribute to sorption inhibition. Complexation between polar functional groups on BC200 and heavy metals slightly enhanced the sorption of neutral naphthalene and significantly enhanced that of anionic 4-nitro-1-naphtol, while limited the sorption of cationic propranolol. Heavy metals together with their associated water molecules decreased the sorption of target chemicals on BC700 via pore-filling or pore-mouth-covering. Inhibition of heavy metals for 4-nitro-1-naphthol was found to be the weakest due to the bridge effects of heavy metals between 4-nitro-1-naphtol and BC700. The higher polarizability of Ag+ led to the increase of its sorption on biochars in the presence of organic aromatic pollutants. The results of the present study shed light on the sorption mechanisms of bi-solute systems and enable us to select suitable biochar sorbents when chemicals co-exist.Download high-res image (410KB)Download full-size image

•Both neutral and ionic PFASs can be transported to an isolated island via atmosphere.•Particulate matter is an important carrier of PFASs during atmospheric transport.•Ionic PFASs were found at substantial levels both in gas and particle phases.•The temperature-dependent partitioning of FTOHs to particles was significant in winter.•DiPAPs were detected only in particle phase with a low level range of 0.02–6.72 pg m−3.Air samples were collected using high-volume samplers at two coastal towns on the Bohai Sea in China, 320 km apart, and at a background site (North Huangcheng Island) in the Bohai Sea, 50 km from the coast. A suite of neutral and ionic per- and poly-fluoroalkyl substances (PFASs) was investigated. Urban activity was related to high levels of neutral PFASs at Tianjin while perfluorooctanoic carboxylic acid (PFOA) was dominant in the atmosphere at Weifang, possibly due to industrial sources. Polyfluoroalkyl phosphoric acid diesters (diPAPs) occurred in the particle phase only, with a total concentration range of 0.02–6.72 pg m−3. The dominant homologue was 6:2 diPAP. PFASs profiles at NHI suggested direct atmospheric transport of neutral and ionic PFASs from source regions. Temperature-dependent partitioning of fluorotelomer alcohols (FTOHs) was observed in winter, when total concentrations and particle-phase fractions of FTOHs were significantly higher as compared to those in summer. Correlation analyses suggested more active gas-phase degradation of FTOHs in summer and likely heterogeneous degradation in both seasons. Overall, it is necessary to account for ionic PFASs in both gas and particle phases and particulate matter was important for atmospheric transport and for determining the fate of PFASs, especially in areas close to a source region.Download high-res image (298KB)Download full-size image

To study the uptake pathways of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDs) in wheat, four closed chambers were designed to expose wheat to HBCDs via air and/or soil for 4 weeks. The results showed that HBCDs could be absorbed by wheat both via root from soil and via leaf from air. The Rt values (ratio of HBCDs from root-to-leaf translocation to the total accumulation in leaves) ranging from 14.4 to 29.8% suggested that acropetal translocation within wheat was limited. A negative linear relationship was found between log Rt and log Kow of the HBCD diastereoisomers (p < 0.05). The bioconcentration factors (BCFs, (μg/g wheat tissues)/(μg/g soil)) were in the order α- > β- > γ-HBCD in wheat roots and stems, being negatively related to their Kow values. No such correlation was found in leaves, where the HBCDs came mainly from air distribution. The results of enantiomeric fractions indicated that the (−)-enantiomer of α- and γ-HBCDs and the (+)-β-enantiomer were selectively accumulated. Furthermore, β- and γ-HBCDs were transformed to α-HBCD in the wheat, with 0.309–4.80% and 0.920–8.40% bioisomerization efficiencies at the end of the experiment, respectively, being the highest in leaves. Additionally, no isomerization product from α-HBCD was found.

From eastern to western areas, per- and polyfluoroalkyl substances (PFASs) were detected at substantial levels in the outdoor dust across mainland China. Urban samples generally showed higher levels compared with those of rural samples. Compared with neutral PFASs, ionizable PFASs (C4–C12 perfluoroalkyl carboxylic acids and C4/C8 perfluoroalkyl sulfonic acids) were more abundant, with the highest total concentration up to 1.6 × 102 ng/g and perfluorooctanoic acid (PFOA) being a predominant analogue. Fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphoric acid diesters (DiPAPs) were both detected in most samples with total concentrations of 0.12–32 and 0.030–20 ng/g, respectively. Perfluorooctane sulfonamidoethanols/sulfonamides (FOSE/As) were detected at low frequencies (<30%). In addition to partitioning to organic moiety, specific adsorption onto mineral particles can be important for PFASs to bind onto outdoor dust, especially for short-chain ionizable PFASs. The eastern plain areas were characterized by a higher contribution of long-chain ionizable PFASs; whereas the western high plateau areas were characterized by the dominating contribution of short-chain analogues. The difference suggests that the long-range atmospheric transport potential of PFASs from source regions to the inland is probably limited by the increase in altitude, and different sources from adjacent regions may influence the western border area of China.

Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon (PAH), which has carcinogenic potency, is highly recalcitrant and resistant to microbial degradation. A novel fungus, Lasiodiplodia theobromae (L. theobromae), which can degrade BaP as a sole carbon source in liquid, was isolated in our laboratory. To prompt the further application of L. theobromae in remediation of sites polluted by BaP and other PAHs, the present study was targeted toward the removal of BaP and PAHs from soil by L. theobromae. The degradation of BaP by L. theobromae was studied using a soil spiked with 50 mg/kg BaP. L. theobromae could remove 32.1 % of the BaP after 35 days of cultivation. Phenanthrene (PHE) inhibited BaP degradation as a competitive substrate. The tested surfactants enhanced BaP degradation in soil by different extents, and a removal rate of 92.1 % was achieved at a Tween-80 (TW-80) concentration of 5 g/kg. It was revealed that TW-80 could not only enhance BaP bioavailability by increasing its aqueous solubility and decreasing the size of its colloid particles but also increase enzyme secretion from L. theobromae and the population of L. theobromae. Moreover, ergosterol content together with the biomass C indicated the increase in L. theobromae biomass during the BaP biodegradation process in soils. Finally, a soil from a historically PAH-contaminated field at Beijing Coking Plant in China was tested to assess the feasibility of applying L. theobromae in the remediation of polluted sites. The total removal rate of PAHs by L. theobromae was 53.3 %, which is 13.1 % higher than that by Phanerochaete chrysosporium (P. chrysosporium), an effective PAH degrader. The addition of TW-80 to the field soil further enhanced PAH degradation to 73.2 %. Hence, L. theobromae is a promising novel strain to be implemented in the remediation of soil polluted by PAHs.

Although levels of poly- and perfluoroalkyl substances (PFASs) in human maternal and neonatal blood have been widely reported in the literature, relationship of maternal–fetal transmission of PFASs with carbon chain length is presently not well understood. In this study, 11 PFASs were analyzed in matched samples, including not only maternal blood (MB, n = 31) and cord blood (CB, n = 30), but also placenta (n = 29) and amniotic fluid (AF, n = 29). Except for perfluorohexanoic acid (PFHxA), the detection frequencies of PFASs were similar among placenta, MB, and CB (>80% for 8 PFASs, nondetectable for 2 PFASs). Though only perfluorooctanoic acid (PFOA) was frequently detected (>90%) in AF, with a median concentration of 0.043 ng/mL, other 5 PFASs were also detectable in AF samples with low concentrations (mean: 0.013–0.191 ng/mL). This suggests that in addition to blood-borne in utero exposure, the fetus is also exposed to low levels of PFASs through AF. Concentrations of PFOA in AF were positively correlated with those in MB (r = 0.738, p < 0.01) and CB (r = 0.683, p < 0.001), suggesting that AF concentration could reflect fetal PFOA exposure during pregnancy and can be used as a biomarker. To clarify the effects of carbon chain length on maternal transfer of PFASs, we calculated maternal transfer efficiencies of PFASs from MB to CB (TMB-CB). A U-shaped trend in TMB-CB of C7–C12 perfluoroalkyl carboxylic acids (PFCAs) with increasing carbon chain length was found in this study for the first time. The U-shaped TMB-CB of PFCAs with carbon chain length is an integrated result of opposite trend of the ratios between MB/placenta and placenta/CB based on carbon chain length. This is the first study to report the occurrence of PFASs in human placenta. The results reported here enable better understanding of the maternal–fetal transmission of PFASs.

A highly sensitive method for the simultaneous trace (ng/L) quantification of seven commonly used artificial sweeteners in a variety of water samples using solid-phase extraction and ion-pair high-performance liquid chromatography (HPLC) triple quadrupole mass spectrometer with an electrospray ionization source (ESI-MS) in negative ion multiple reaction monitoring mode was developed. Ten solid phase extraction (SPE) cartridges were tested to evaluate their applicability for the pre-concentration of the analytes, and their loading and eluting parameters were optimized. Satisfactory recoveries (77–99%) of all of the studied sweeteners were obtained using a Poly-Sery PWAX cartridge with 25 mM sodium acetate solution (pH 4) as wash buffer and methanol containing 1 mM tris (hydroxymethyl) amino methane (TRIS) as eluent. The method is sound and does not require pH adjustment or buffering of water samples. The HPLC separation was performed on an Athena C18-WP column with water and acetonitrile, both containing 5 mM ammonium acetate and 1 mM TRIS as mobile phases, in gradient elution mode. The linearity, precision, and accuracy of the method were evaluated, and good reproducibility was obtained. Method quantification limits varied between 0.4 and 7.5 ng/L for different water samples. The post-extraction spike method was applied to assess matrix effects, and quantification was achieved using internal standard calibration to overcome the unavoidable matrix effects during ESI-MS analysis. The method was applied to the analysis of thirteen water samples from Tianjin, China, including wastewater, tap water, surface water, and groundwater. The method described here is time-saving, accurate and precise, and is suitable for monitoring artificial sweeteners in different water matrices.Highlights► A novel SPE procedure for the extraction of artificial sweeteners was developed. ► Satisfactory recoveries were obtained without pH adjustment of the samples. ► A sensitive method for the quantification of artificial sweeteners was developed. ► The method was applied for the analysis of thirteen water samples from China. ► Artificial sweeteners occurred ubiquitously in the investigated samples.

Twenty-three polychlorinated and perfluorinated compounds (PFCs) were investigated in water phase and particulate matters of 19 precipitation samples (18 snow samples and 1 rain sample) from different cities across eastern and central China collected in February 2010. The PFCs in samples of 9e precipitation events during more than half a year at 1 site in Tianjin and 6 successive samples during 1 precipitation event were measured to elucidate the change of PFC in precipitation. In addition, PFCs in 3 runoffs at different kinds of sites in Tianjin were compared with those in the corresponding precipitation. The results showed that the particulate matters separated from the precipitation contained undetectable PFCs. The total PFC concentration ranged between 4.7 and 152 ng L−1 in water phase of the precipitation samples, with perfluorooctanoic acid (PFOA) being detected at all of the sampling sites and the dominant PFC at most of the sampling sites. Some potential precursors of environmentally concerned PFCs and their degradation intermediates were measured simultaneously, among which 6:2 fluorotelomer unsaturated carboxylic acid (6:2 FTUCA), 8:2 FTUCA, and  × (3, 4, 5, 7):3 acid [F(CF2)xCH2CH2COOH] were measured for the first time in Chinese precipitations; however, their concentrations were all lower than the limits of detection except that 6:2 FTUCA and 8:2 FTUCA could be detected in 3 and 8 precipitation samples, respectively. No clear seasonal variation in PFC concentrations in precipitation was observed during half a year; however, a relatively greater average concentration of total PFCs was observed during winter and summer compared with spring. The concentration of individual PFCs showed an obvious descending trend in the successive samples of the precipitation event. PFOA and perfluorononanoic acid in runoffs collected from different sites showed the following similar pattern—gas station > highway > university campus—whereas the other detected PFCs had no concurrent trend.

The impacts on the sorption of phenanthrene (PHE) onto single-walled carbon nanotubes (SCNT) by loading of dissolved organic matter (DOM) fractions with different molecular weights (MWs) were studied. Moreover, the influence of contact time on the sorption capacity of DOM-modified SCNT was evaluated for the first time. Preloading of DOM on SCNT for 2 days led to a reduction in PHE sorption and the nonlinearity of the sorption isotherm; however further increasing the contact time between the DOM and SCNT from 2 days to 20 days enhanced the sorption capacity, and the sorption nonlinearity increased also. This is due to the transferring of DOM molecules from the external surface to interstitial channels trapped in SCNT particles, restoring the sorption sites. The loading of DOM fraction with MWs larger than 14000 Da (DOM>14000) brought a stronger suppression of PHE sorption by SCNT compared to smaller ones (DOM<1000 and DOM1000–14000), with the Freundlich nonlinear index n increasing from 0.236 to 1.093 and the Freundlich affinity coefficient log KF decreasing from to 7.34 to 4.57. These are similar to the sorption characteristics of DOM>14000, suggesting a complete coverage of the SCNT by DOM>14000 molecules. Though the loading of DOM fractions with smaller MWs made SCNT more polar, the reduction in PHE sorption on DOM-preloaded SCNT was limited due to their lesser sorbed amount and smaller molecular size.

Perfluorinated compounds (PFCs) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. Wastewater treatment plants (WWTPs) are fundamental utilities in cities, playing an important role in preventing water pollution by lowering pollution load in waste waters. However, some of the emerging organic pollutants, like PFCs cannot be efficiently removed by traditional biological technologies in WWTPs, and some even increase in effluents compared to influents due to the incomplete degradation of precursors. Hence, WWTPs are considered to be a main point source in cities for PFCs that enter the aquatic environment. However, the mass flow of PFCs from WWTPs has seldom been analyzed for a whole city. Hence, in the present study, 11 PFCs including series of perfluoroalkyl carboxylic acids (PFCAs, C4–C12) and two perfluoroalkyl sulfonates (PFASs, C6 and C8) were measured in WWTP influents and effluents and sludge samples from six municipal WWTPs in Tianjin, China. Generation and dissipation of the target PFCs during wastewater treatment process and their mass flow in effluents were discussed.All the target PFCs were detected in the six WWTPs, and the total PFC concentration in different WWTPs was highly influenced by the population density and commercial activities of the corresponding catchments. Perfluorooctanoic acid (PFOA) was the predominant PFC in water phase, with concentrations ranging from 20 to 170 ng/L in influents and from 30 to 145 ng/L in effluents. Concentrations of perfluoroalkyl sulfonates decreased substantially in the effluent compared to the influent, which could be attributed to the sorption onto sludge, whereas concentrations of PFOA and some other PFCAs increased in the effluent in some WWTPs due to their weaker sorption onto solids and the incomplete degradation of precursors. Perfluorooctane sulfonic acid (PFOS) was the predominant PFC in sludge samples followed by PFOA, and their concentrations ranged from 42 to 169 g/kg and from 12 to 68 g/kg, respectively. Sludge-wastewater distribution coefficients (log Kd) ranged from 0.62 to 3.87 L/kg, increasing with carbon chain length of the homologues. The mass flow of some PFCs in the effluent was calculated, and the total mass flow from all the six municipal WWTPs in Tianjin was 26, 47, and 3.5 kg/year for perfluorohexanoic acid, PFOA, and PFOS, respectively.

Despite the growing public interest in perfluorinated compounds (PFCs), very few studies have reported the sources and pathways of human exposure to these compounds in China. In this study, concentrations of 10 PFCs were measured in human blood, water (tap water and surface water), freshwater fish, and seafood samples collected from China. On the basis of the data, we calculated daily intakes of PFCs, regional differences in human exposures, and potential risks associated with ingestion of PFCs from diet, drinking water, and indoor dust for the Chinese population. Perfluorooctane sulfonate (PFOS) was the most predominant PFC found with a mean concentration of 12.5 ng/mL in human blood from Tianjin and 0.92 ng/g wet wt in freshwater fish and seafood; perfluorooctanoic acid (PFOA) was the major PFC found in drinking water at a concentration range of 0.10 to 0.92 ng/L. The estimated daily intake of PFOS and PFOA via fish and seafood consumption (EDIfish&seafood) ranged from 0.10 to 2.51 and 0.13 to 0.38 ng/kg bw/day, respectively, for different age groups (i.e., toddlers, adolescents and children, and adults) from selected locations (i.e., Tianjin, Nanchang, Wuhan, and Shenyang). The EDIfish&seafood of PFCs decreased (p < 0.05) with age. The estimated daily intake of PFOS and PFOA via drinking water consumption (EDIdrinking water) ranged from 0.006 to 0.014 and 0.010 to 0.159 ng/kg bw/day, respectively. Comparison of EDIfish&seafood and EDIdrinking water values with those of the modeled total dietary intake (TDI) of PFCs by adults from Tianjin, Nanchang, Wuhan, and Shenyang showed that contributions of fish and seafood to TDI of PFOS varied depending on the location. Fish and seafood accounted for 7%, 24%, 80%, and 84% of PFOS intake in Nanchang, Shenyang, Wuhan, and Tianjin, respectively, suggesting regional differences in human exposure to PFOS. Drinking water was a minor source of PFOS (<1%) exposure in adults from all the study locations.

In this study, 10 perfluorochemicals (PFCs) were measured in meat, meat products, and eggs, and in indoor dust, collected in China. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were the most frequently detected PFCs in these samples. Mean concentrations of PFOS and PFOA in foodstuffs were in the range of 0.05−1.99 ng/g fresh wt and 0.06−12.5 ng/g fresh wt, respectively. The mean concentrations of PFOA, perfluoroheptanoic acid (PFHpA), and PFOS in indoor dust were 205, 14.0, and 4.86 ng/g, dry wt, respectively. The estimated daily intake of PFOS and PFOA from meat, meat products and eggs (EDImeat&eggs) ranged from 6.00 to 9.64 ng/d and from 254 to 576 ng/d, respectively, when the values below the limit of quantitation (LOQ) were assigned as 0, and from 8.80 to 15.0 ng/d and from 255 to 577 ng/d, respectively, when the values below the LOQ were set at 1/2LOQ. The EDImeat&eggs of PFOS and PFOA increased with increasing family income. The estimated daily intake of PFOS and PFOA through inhalation of dust (EDIdust) ranged from 0.23 to 0.31 ng/d and from 9.68 to 13.4 ng/d, respectively. The daily intakes of PFOS and PFOA from the consumption of meat, meat products, and eggs, and from dust ingestion, as calculated from our samples in this study, were compared with estimated daily intake of PFCs reported from the concentrations in drinking water, fish and seafood from China. Our calculations indicate that dietary sources (EDIdietary) account for the overwhelming proportion of (>99% for PFOS and 98% for PFOA) total daily intake (TDI) in adults. The analyzed foodstuffs (meat, meat products, and eggs) were not the major contributors to dietary exposure to PFOS, whereas, meat was the primary contributor to dietary exposure to PFOA.

Two hundred and forty five human blood (whole blood) samples from Chinese donors aged from 0 to 90 yrs were analyzed for 10 perfluorinated compounds (PFCs). Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the most abundant PFCs found in blood. The median concentration of PFOS was lower in nonadults (i.e., infants, toddlers, children, and adolescents) (2.52−5.55 ng/mL) than in adults (8.07 ng/mL). However, median concentration of PFOA in nonadults (1.23−2.42 ng/mL) was higher than that found in adults (1.01 ng/mL). A significant increase in PFOS (r = 0.468, p < 0.01) and perfluorohexane sulfonate (PFHxS) (r = 0.357, p < 0.01) concentrations with age was found, while PFOA concentrations (r = −0.344, p < 0.01) were negatively correlated with age. No significant gender-related differences in PFC concentrations were found across all ages. The composition profiles of PFCs, as identified by principal component analysis, varied for each age group; this suggested differences in sources and pathways of exposure to PFCs for different age groups. Based on the blood PFC concentration, we estimated the daily intake of PFOS by adults using a one-compartment toxicokinetic model. The modeled daily intake of PFOS agreed well with the calculated daily intake via diet and indoor dust (0.74 vs 1.19 ng/kg b.w. for males, 1.20 vs 1.15 ng/kg b.w. for females) suggesting that dietary intake and dust ingestion are the major exposure routes to PFOS exposure in China. This is the first comprehensive study on PFCs in human blood from infants, toddlers, children, and adolescents in China. The data are valuable for understanding the sources and pathways of human exposure to PFCs for different age groups.

A rapid and reliable analytical method, based on ion-pair extraction, clean-up on Envicarb cartridge and detection by liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for determination of 17 per- and polyfluorinated chemicals (PFCs) in digested sewage sludge. Envicarb cartridge and six labeled internal standards were selected for the elimination/reduction and correction of matrix effects, respectively. As a result, the matrix effect for perfluorooctane sulfonamides (FOSAs) and perfluorocarboxylic acids (PFCAs) with carbon chain length from C6 to C14 was lowered to a range of −14% to +28%. However, the matrix effect for other analytes was still great mainly due to the absence of appropriate internal standard. Mean recoveries of the target analytes based on matrix spikes, at different spike levels (10–300 ng/g), ranged from 70% to 169%. Relative standard deviations (RSDs) were in the range of 2–20% at different spike levels. The limit of quantification (LOQ) ranged between 0.6 and 30 ng/g. The method was successfully applied to several sewage sludge samples from wastewater treatment plants nearby Zürich, Switzerland. In addition, by comparing the accuracy and precision of ion-pair extraction method and methanol extraction method, we further demonstrated that the ion-pair extraction method can be used for the analysis of PFCs in sludge samples. To our knowledge, this is the first study to extract the PFCs in sewage sludge with ion-pair method and to find unsaturated fluorotelomer carboxylic acids (FTUCAs) in sewage sludge.

Nonylphenol polyethoxylates (NPnEO) and nonylphenol (NP) have drawn much environmental concern because of their weak estrogenic activities. The present study focused on the spatial distribution of NPnEO and NP in surface sediments and their corresponding porewaters along Lanzhou Reach of Yellow River, China. Long EO chain NPnEO analogs with n > 2 were not measurable in most sediment and porewater samples, so only NP, nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) were discussed in this study. Concentrations of NP, NP1EO, and NP2EO in the sediments ranged from 61.3 to 113.9, 31.1 to 55.9, and 47.9 to 74.1 ng/g dry weight, respectively. A significant correlation (R2 = 0.56, p < 0.01) was observed between NP levels and organic carbon content of the sediments, whereas no correlation was found for the more hydrophilic NP1EO and NP2EO. The concentrations of NP, NP1EO, and NP2EO in the porewaters ranged from 0.35 to 1.95, 0.06 to 0.63, and 0.08 to 0.38 μg/L. The mean in situ log Koc values (n = 13, S1 excluded) of NP, NP1EO, and NP2EO were 4.48, 4.94, and 5.06, respectively, which were lower than those measured in batch adsorption experiments.

The purpose of this study is to estimate the removal efficiency of As and Cr (VI) by one kind of industrial waste — iron chips, as well as to estimate the effects of typical inorganic anions (sulfate, phosphate, and nitrate), and typical organic anions (citrate, oxalate, and humate) on As or Cr (VI) removal. The results showed that 98% of As (V) and 92% of As (III) could be removed from aqueous phase by the iron chips within 60 min. Compared with As species, Cr (VI) was removed much more rapidly and efficiently with 97% of Cr (VI) being removed within 25 min. The removal efficiency for arsenic was in the order: As (III) (sulfate), As (III) (nitrate) or As (III), As (III) (humate), As (III) (oxalate), As (III) (citrate), As (III) (phosphate), and for chromate was in the order: Cr (VI) (sulfate), Cr (VI) (phosphate) or Cr (VI) (nitrate) or Cr (VI) (oxalate), Cr (VI), Cr (VI) (citrate), Cr (VI) (humate). In all the treatments, pH level increased with time except for As (III), the removal of which was either without anions or in the presence of humate or nitrate.

The concentration and distribution of nonylphenol polyethoxylates (NPEOs represents the mixture, and NPnEO represents the monomer) and its metabolites in the influent and effluent of four municipal sewage treatment plants (STPs) in the north of China were measured. Moreover, the concentration and distribution of the above chemicals in the sludge of two STPs were also determined, and the transfer and fate of NPEOs in the sewage treatment process were discussed primarily by analyzing the distribution of the products in the effluent and the sludge. The results showed that NPEOs and its metabolites existed in all the samples of the influent, effluent, and sludge. NPEOs were degraded in the sewage treatment process with the removal efficiency in the range of 23.38%–77.11%, or an average of 52.86%. However, the large analogs of NPnEO were only degraded to small ones, whose degradation rate was rather slow, and consequently the degradation was not complete. Hence, the concentrations of some small metabolites, such as nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) were elevated in the effluent. These small metabolites are more toxic than the large NPnEO analogs, and some of them were reported to exhibit environmental endocrine disrupting activity. From this point of view, the process of sewage treatment does not reduce but elevate the risk of NPEOs, which becomes the main source of these small NPnEO in the environment. The sludge exhibited good adsorption ability for NPEOs, especially for the small analogs, which led to the high level of NPEOs in the sludge. Hence, reasonable disposal of the surplus sludge to avoid re-pollution is very important.

•Bioaugmentation assisted by biostimulation (BAB) is a promising remediation approach.•The morphology of the B38, a UV-mutant species changed after mutation.•More functional groups were found in B38, leading to its high Cd fixing capacity.•The positive effect of B38 could exhibit only in BAB technology.•BAB technology could enhance the growth of both exotic B38 and native microbes.To develop an efficient bio-immobilization technology for the remediation of heavy metals in soil, a mutant species of Bacillus subtilis (B38) was acquired by UV irradiation and selection under high concentration of cadmium (Cd) in a previous study. Immobilization of Cd in soil has been achieved and reported earlier by a technology of bioaugmentation of B38 assisted by biostimulation (BAB) using a bio-waste (NovoGro) from an enzyme company. In the present study, B38 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR). The results proved that the cell morphology and functional groups on the cell surface of B. subtilis changed after the mutation and interaction with Cd. The applicability of BAB as a practicable bioremediation technology was evaluated by checking the inhibition on Cd bioaccumulation by carrots (Daucus carota), the enhancement on carrot biomass, and the change of Cd speciation in soil. The BAB technology reduced Cd contents in carrot shoots and roots by 16% and 55%, respectively. Simultaneously, the exchangeable fraction of Cd in soil under BAB treatment decreased significantly. Furthermore, a PCR-DGGE-based experiment was performed to evaluate the effect of BAB technology on soil microbial communities. The BAB technology could enhance the proliferation of both exotic B38 and native microbes.

•A point source of HBCDs brought extensive impacts on the vicinal environment.•An increasing temporal trend of HBCDs in the sediment was noted.•HBCDs could be biomagnified along with food chain in the Bohai Bay.•α-HBCD was preferentially enriched in organisms especially in marine species.•Enantiomer fractions of HBCDs in collected samples were reported.To investigate the environmental fate of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDs), samples from various environmental media, including outdoor settled dust, soil, sediment, plant tissues (holly, cypress and pine) and marine species (shrimp, crab and fish) were obtained around an expanded polystyrene material manufacturing plant in Tianjin, China. The 3 main HBCD diastereoisomers were detected with the total concentrations ranging from 328 to 31,752 ng/g dry weight (dw), 2.91–1730 ng/g dw, 23.5–716 ng/g dw, 3.45–2494 ng/g dw, and 0.878–44.8 ng/g dw in the dust, soil, sediment, plant tissues, and marine species, respectively. This indicated that a point source of HBCDs could bring wide impact on its vicinal environment. A significant increasing trend of HBCDs concentrations was noted, as indicated by 12.9–41.6% of increasing rates in total concentrations of HBCDs at four sediment sites in the past five years. The diastereoisomer profiles were sorted into 3 groups: dust, soil and sediment, which had no statistical difference from commercial EPS-products (p > 0.05); plant tissues, which showed a moderate increase of α-isomer (22.9 ± 3.3%); and marine species, which were dominated by α-isomer (62.6 ± 2.8%). For α- and β-isomers, the results of enantiomeric analysis showed a preferential accumulation of the (+)-enantiomer in part of plant tissues and all marine organisms (p < 0.05). However, there was no enantioselectivity of the 3 isomers in dust, soil, and sediment samples (p > 0.05). Besides, marine food web magnification is observed for HBCDs, with trophic magnification factors close to 2. The daily intakes of HBCDs were estimated to be 0.058–5.84 ng/kg-bw/day for local residents through dust and soil ingestion and 0.048–8.43 ng/kg-bw/day for Tianjin citizens through seafood consumption.Download high-res image (306KB)Download full-size image

•Biochar and CNT amendment reduced the bioavailability of HBCDs to earthworms.•The reduction in HBCD bioaccumulation was greater in E. fetida than M. guillelmi.•The amendments did not alter the isomer selectivity in HBCD bioaccumulation.•HBCDs in soils resisted desorption, with Frap < Fslow.•24 h-desorption is a good proxy for the bioavailability of HBCDs to earthworms.Biochar is a promising material used in soil amendment and carbon nanotubes may enter soil due to its increasing application. These carbonaceous materials may change the bioavailability of pollutants in soil. In this concern, 0.5% w/w multi-walled carbon nanotubes (MWCNTs) and 3 corn-straw biochars acquired at different pyrolyzing temperatures were used in soil amendment and their influences on the bioavailability of hexabromocyclododecanes (HBCDs), a brominated flame retardant, to 2 ecologically different earthworm species were studied. The amendment of 4 carbonaceous materials all reduced the bioaccumulation of HBCDs in earthworms by 18.2%–67.3%, which varied depending on the type of carbonaceous materials and the pyrolyzing temperature of biochars. The reduction in HBCDs uptake by Eisenia fetida (an epigeic species) was greater than by Metaphire guillelmi (an anecic species). The 2 earthworm species both showed bioaccumulative selectivity on certain HBCD diastereoisomer and enantiomer in the amended soils, which was similar to that in the control soil. Moreover, Tenax-assisted HBCDs desorption test was carried out for the simulation of their bioavailability. The rapid desorption fraction (Frap), total desorption (15 d), and 24 h desorption all correlated well with the uptake of HBCDs in the earthworms, suggesting that the 24 h-desorption, due to its easy availability, can be a good proxy to predict the bioavailability of HBCDs to earthworms in soil.Download high-res image (245KB)Download full-size image

•Salt stress reduced the removal efficiencies of nitrogen (N) and phosphorus (P) by duckweed (Lemna minor).•Salt stress inhibited duckweed growth and chlorophyll synthesis.•Severe salt stress induced negative removal of N and P by duckweed.•Duckweed with long-term cultivation suffered more injury under severe salt stress.•L. minor is suitable for N and P removal in water with salinities below 50 mM NaCl or equivalent salt stress.Duckweed plays a major role in the removal of nitrogen (N) and phosphorus (P) from water. To determine the effect of salt stress on the removal of N and P by duckweed, we cultured Lemna minor, a common species of duckweed, in N and P-rich water with NaCl concentrations ranging from 0 to 100 mM for 24 h and 72 h, respectively. The results show that the removal capacity of duckweed for N and P was reduced by salt stress. Higher salt stress with longer cultivation period exerts more injury to duckweed and greater inhibition of N and P removal. Severe salt stress (100 mM NaCl) induced duckweed to release N and P and even resulted in negative removal efficiencies. The results indicate that L. minor should be used to remove N and P from water with salinities below 75 mM NaCl, or equivalent salt stress.Download high-res image (137KB)Download full-size image

In this study, acesulfame (ACE), saccharin (SAC) and cyclamate (CYC) were found in all paired urine and blood samples collected from healthy adults, with mean values of 4070, 918 and 628 ng mL−1, respectively, in urine and 9.03, 20.4 and 0.72 ng mL−1, respectively, in blood. SAC (mean: 84.4 ng g−1) and CYC (4.29 ng g−1) were detectable in all liver samples collected from liver cancer patients, while ACE was less frequently detected. Aspartame (ASP) was not found in any analyzed human sample, which can be explained by the fact that this chemical metabolized rapidly in the human body. Among all adults, significantly positive correlations between SAC and CYC levels were observed (p < 0.001), regardless of human matrices. Nevertheless, no significant correlations between concentrations of SAC (or CYC) and ACE were found in any of the human matrices. Our results suggest that human exposure to SAC and CYC is related, whereas ACE originates from a discrete source. Females (or young adults) were exposed to higher levels of SAC and CYC than males (or elderly). The mean renal clearance of SAC was 730 mL per day per kg in adults, which was significantly (p < 0.001) lower than those for CYC (10800 mL per day per kg) and ACE (10300 mL per day per kg). The average total daily intake of SAC and ACE was 9.27 and 33.8 μg per kg bw per day, respectively.

The impacts on the sorption of phenanthrene (PHE) onto single-walled carbon nanotubes (SCNT) by loading of dissolved organic matter (DOM) fractions with different molecular weights (MWs) were studied. Moreover, the influence of contact time on the sorption capacity of DOM-modified SCNT was evaluated for the first time. Preloading of DOM on SCNT for 2 days led to a reduction in PHE sorption and the nonlinearity of the sorption isotherm; however further increasing the contact time between the DOM and SCNT from 2 days to 20 days enhanced the sorption capacity, and the sorption nonlinearity increased also. This is due to the transferring of DOM molecules from the external surface to interstitial channels trapped in SCNT particles, restoring the sorption sites. The loading of DOM fraction with MWs larger than 14000 Da (DOM>14000) brought a stronger suppression of PHE sorption by SCNT compared to smaller ones (DOM<1000 and DOM1000–14000), with the Freundlich nonlinear index n increasing from 0.236 to 1.093 and the Freundlich affinity coefficient log KF decreasing from to 7.34 to 4.57. These are similar to the sorption characteristics of DOM>14000, suggesting a complete coverage of the SCNT by DOM>14000 molecules. Though the loading of DOM fractions with smaller MWs made SCNT more polar, the reduction in PHE sorption on DOM-preloaded SCNT was limited due to their lesser sorbed amount and smaller molecular size.