•MIL-53(Fe) is successfully synthesized as a novel photocatalytic adsorbent.•MIL-53(Fe) shows high adsorption capacities for CA and CBZ.•Photodegradation efficiencies for CA and CBZ reach 90% in MIL-53(Fe)/H2O2/vis system.•MIL-53(Fe) can be recycled and applied in real wastewater treatment.The development of efficient materials for removing pharmaceuticals from water has been a matter of great concern. As a new class of porous materials, metal-organic frameworks (MOFs) have attracted considerable attention in the field of environmental remediation. In this article, a photocatalytic adsorbent MIL-53(Fe) was successfully prepared by solvothermal method and used for the removal of two typical pharmaceuticals clofibric acid (CA) and carbamazepine (CBZ) from water. MIL-53(Fe) exhibited good adsorption performance and the maximum adsorption capacities of CA and CBZ are about 0.80 mmol/g and 0.57 mmol/g, respectively. The adsorption mechanisms of CA and CBZ are mainly due to electrostatic interaction and π-π interaction, respectively. Further, MIL-53(Fe) exhibited high photocatalytic activity and stability under visible light. The photocatalytic efficiency could be improved significantly with the addition of a small amount of H2O2, and the corresponding photodegradation efficiencies for CA and CBZ both reached up to 90%, which are higher than those of Fe(II)/H2O2 and TiO2 under visible light. The photocatalytic performance was strongly dependent on the solution pH. The Fenton-like reaction, charge carriers directly generated in the photo-excited MIL-53(Fe) and the synergistic effect of H2O2 were the main mechanisms. The formation of humic acids-like and fulvic acids-like organic matter in the degradation process was detected by 3D EMMs. MIL-53(Fe) also revealed excellent performance for the removal of CA and CBZ from real municipal wastewater and river water. Therefore, MIL-53(Fe) may be used as a promising photocatalytic adsorbent for wastewater purification.Download high-res image (124KB)Download full-size image

Bezafibrate (BF), a frequently detected pharmaceutical in the aquatic environment, could be effectively removed by ozonation. However, the toxicity of treated water increased, suggesting the generation of toxic oxidation products (OPs). In this study, eight OPs of BF ozonation were identified using a LTQ Orbitrap hybrid mass spectrometer coupled with HPLC, and six of them have not been previously reported during BF ozonation. Based on the abundant fragments and high assurance of accurate molar mass, structure elucidation was comprehensively performed and discussed. Hydroxylation, loss of methyl propionic acid group, and Crigée mechanism were observed as the oxidation mechanisms of BF ozonation. The toxicity of identified OPs calculated by quantitative structure activity relationship indicated that three OPs were probably more toxic than the precursor compound BF. This result together with the evolution of identified OPs in the treated solutions, indicated that two OPs, namely N-(3,4-dihydroxyphenethyl)-4-chlorobenzamide and N-(2,4-dihydroxyphenethyl)-4-chlorobenzamide, were the potential toxicity-causing OPs during BF ozonation. To the best of our knowledge, this is the first attempt to identify toxicity-causing OPs during the BF ozonation.

•An in silico method was developed to assess ozonation pathways and products.•The method is mechanism based, easy operating and suitable for programming.•Ozonation pathways and products of sulfamethoxazole were assessed as a case.•Predicted intermediate products were verified by experimental observations.•The method predicts minor pathways or products difficultly observed by experiments.Ozonation is widely used in wastewater treatment plants to remove diverse organic micropollutants. As molecular structures of organic micropollutants contain multiple ozone-preferred reaction sites, and moreover intermediate products can react with ozone again, ozonation mechanism is complex. A fast increasing number of organic micropollutants and a great demand of ecological risk assessments call for an in silico method to provide insights into the ozonation mechanism of organic micropollutants. Here, an in silico model was developed to unveil ozonation mechanisms of organic micropollutants. Sulfamethoxazole was taken as a case. The model enumerates elementary reactions following well-accepted ozonation patterns and secondary transformation reactions established for intermediates by experiments. Density functional theory (DFT) calculations were employed for evaluating thermodynamic feasibilities of reaction pathways. By calculating Gibbs free energies, ozonation products of SMX were predicted. The predicted products are consistent with those detected in experiments. This method is advanced in revealing all possible reaction pathways including minor pathways that produce toxic byproducts but are difficult to be observed by experiments. Accordingly, water treatment engineers can setup necessary treatment technology to ensure water safety.Download high-res image (184KB)Download full-size image

Promising applications of metal–organic frameworks (MOFs) in various fields have raised concern over their environmental fate and safety upon inevitable discharge into aqueous environments. Currently, no information regarding the transformation processes of MOFs is available. Due to the presence of repetitive π-bond structure and semiconductive property, photochemical transformations are an important fate process that affects the performance of MOFs in practical applications. In the current study, the generation of reactive oxygen species (ROS) in isoreticular MIL-53s was studied. Scavengers were employed to probe the production of 1O2, O2•–, and •OH, respectively. In general, MIL-53(Cr) and MIL-53(Fe) are dominated by type I and II photosensitization reactions, respectively, and MIL-53(Al) appears to be less photoreactive. The generation of ROS in MIL-53(Fe) may be underestimated due to dismutation. Further investigation of MIL-53(Fe) encapsulated diclofenac transformation revealed that diclofenac can be easily transformed by MIL-53(Fe) generated ROS. However, the cytotoxicity results implied that the ROS generated from MIL-53s have little effect on the viability of the human hepatocyte (HepG2) cell line. These results suggest that the photogeneration of ROS by MOFs may be metal-node dependent, and the application of MIL-53s as drug carriers needs to be carefully considered due to their high photoreactivity.

To examine the effects of different functionalization methods on adsorption behavior, anionic-exchange MIL-101(Cr) metal–organic frameworks (MOFs) were synthesized using preassembled modification (PAM) and postsynthetic modification (PSM) methods. Perfluorooctanoic acid (PFOA) adsorption results indicated that the maximum PFOA adsorption capacity was 1.19 and 1.89 mmol g–1 for anionic-exchange MIL-101(Cr) prepared by PAM and PSM, respectively. The sorption equilibrium was rapidly reached within 60 min. Our results indicated that PSM is a better modification technique for introducing functional groups onto MOFs for adsorptive removal because PAM places functional groups onto the aperture of the nanopore, which hinders the entrance of organic contaminants. Our experimental results and the results of complementary density functional theory calculations revealed that in addition to the anion-exchange mechanism, the major PFOA adsorption mechanism is a combination of Lewis acid/base complexation between PFOA and Cr(III) and electrostatic interaction between PFOA and the protonated carboxyl groups of the bdc (terephthalic acid) linker.

Homolog and congener profiles of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in commercial PCBs formulations are useful information for the source appointment of PCBs contamination as well as the risk assessment caused by potential exposure. Dielectric oil (ASKAREL Nr 1740) in an imported transformer found in China was sampled and analyzed by isotope dilution technology using high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS). The detailed homolog and congener profiles of PCBs obtained were compared with those of known Aroclor formulations. High similarity in the homolog profile between the oil sample and Aroclor 1260 was found, with the hexachlorinated and heptachlorinated biphenyls accounting for more than 80.2% of the total PCBs concentration. Severn indicator PCBs contribute about 30%, while 12 PCB congeners (i.e., #153, #143, #168, #180, #149, #165, #138, #170, #190, #187, #174, #181) account for more than 50% of the total PCB concentrations. Total concentration of PCDDs, PCDFs and dioxin-like PCBs (DL-PCBs) was found to be 740 ng TEQ/g, of which 620 ng TEQ/g came from DL-PCBs. The contribution of PCDDs to the total TEQ was neglectable. The concentration of PCDFs homologs follows the order of OCDF>HxCDFs>HpCDFs>PeCDFs>TeCDFs, which is in consistence with the previous study on Aroclor 1260. Three DL-PCBs congeners (i.e., #118, #156, #157) accounted for 77% of the total concentration of DL-PCBs, also they contribute 72% in the TEQ caused by DL-PCBs.

The application of appropriate advanced treatment process in the municipal wastewater treatment plants (WWTPs) has become an important issue considering the elimination of emerging contaminants, such as pharmaceutical and personal care products (PPCPs). In the present study, the removal of 13 PPCPs belonging to different therapeutic classes by the sequential ultraviolet (UV) and ozonation process in a full-scale WWTP in Beijing was investigated over the course of ten months. Most of the target PPCPs were effectively removed, and the median removal efficiencies of individual PPCPs, ranging from − 13% to 89%, were dependent on their reaction rate constants with molecular ozone. Noticeable fluctuation in the removal efficiencies of the same PPCPs was observed in different sampling campaigns. Nevertheless, the sequential UV and ozonation process still made a significant contribution to the total elimination of most PPCPs in the full-scale WWTP, by compensating for the poor or fluctuant removal performance of PPCPs by biologic treatment process.

Perfluorinated compounds (PFCs) are persistent in environments due to the high energy of CF bond. Electrochemical oxidation of seven PFCs in aqueous solution on a boron doped diamond (BDD) anode was studied in this study. The kinetics results show that the pseudo-first order kinetic constants of perfluoroalkyl carboxyates and sulfonates increased with the increase of carbon chain length. PFCs decomposition began with a direct one electron transfer from carboxyl or sulfonate group to BDD, and the formed PFCs radicals were decarboxylated or desulfonated to yield the perfluoroalkyl radical which permitted a defluorination reaction between perfluoroalkyl radical and hydroxyl radical. The effects of potential, current density, initial pH, and perfluorooctanoate (PFOA) concentration on the removal of PFOA were investigated. The anodic potential played an important role in the decomposition, and the oxidation potential of PFOA was 2.76 vs. SCE/V (saturated calomel electrode). When the current density increased slightly from 0.12 to 0.59 mA cm−2, PFOA removal was greatly enhanced from 0 to 97.48%. PFOA decomposition was higher in acidic solution compared to that in the alkaline solution. The pseudo-first order kinetic constants of PFOA decomposition increased with the increase of initial concentration.Highlights► The first order kinetic constants of PFCs depend on chain length. ► BDD has good electrochemical performances and high current efficiency at 0.59 mA cm−2. ► The intermediate products of PFCs decomposition were short chain PFCAs.

The Stockholm Convention on persistent organic pollutants (POPs) was adopted in 2001. This year is the 10th anniversary of the adoption of the Convention. Until now, 22 chemicals or chemical categories have been listed as POPs in the Stockholm Convention. The POPs Research Center was established in Tsinghua University in the same year when the Convention was adopted. In the last ten years, much work has been done by Chinese researchers to understand the environmental risk of POPs in China. This article aims to review the recent research progress of our POPs Research Center and some other Chinese researchers’ studies in addressing the environmental risk of POPs, including the priority screening and inventory study of POPs, monitoring and modeling of POPs pollution and exposure, and environmental risk assessment and modeling of POPs. Although great advances in addressing the environmental risk of POPs have been made in recent years, we are still facing quite a few problems, such as data scarcity and uncertainty in environmental risk assessment of POPs. The study on the effect of POPs mixtures is in its infancy and currently POPs are usually assessed from legal perspective by risk assessment of single chemicals. These problems should be well addressed by further efforts. Further studies should also be taken in future to study environment risk of POPs by considering aspects of coupled dynamics between climate processes and POPs. Such sound scientific, riskbased information can support decision-making aiming to effectively minimize the risk level of POPs.

The occurrence of 12 pharmaceuticals and personal care products (PPCPs) in two wastewater treatment plants in Beijing was studied monthly over the course of one year. The removal of PPCPs by three biological treatment processes including conventional activated sludge (CAS), biological nutrient removal (BNR), and membrane bioreactor (MBR) was compared during different seasons. Seasonal variations of PPCPs in the wastewater influent were discrepant, while in the wastewater effluent, most PPCPs had lower concentrations in the summer than in the winter. For the easily biodegradable PPCPs, the performance of MBR was demonstrated to be more stable than CAS or BNR especially during winter months. Diclofenac, trimethoprim, metoprolol, and gemfibrozil could be moderately removed by MBR, while their removal by CAS and BNR was much lower or even negligible. Nevertheless, no removal was achieved regardless of the season or the treatment processes for the recalcitrant PPCPs. Studies on the contribution of each tank of the MBR process to the total removal of four biodegradable PPCPs indicated the oxic tank was the most important unit, whereas membrane filtration made a negligible contribution to their elimination.

The electrochemical decomposition of persistent perfluorooctanoate (PFOA) with a Ti/SnO2-Sb-Bi electrode was demonstrated in this study. After 2 h electrolysis, over 99% of PFOA (25 mL of 50 mg·L−1) was degraded with a first-order kinetic constant of 1.93 h−1. The intermediate products including short-chain perfluorocarboxyl anions (CF3COO−, C2F5COO−, C3F7COO−, C4F9COO−, C5F11COO−, and C6F13COO−) and F− were detected in the aqueous solution. The electrochemical oxidation mechanism was revealed, that PFOA decomposition first occurred through a direct one electron transfer from the carboxyl group in PFOA to the anode at the potential of 3.37 V (vs saturated calomel electrode, SCE). After that, the PFOA radical was decarboxylated to form perfluoroheptyl radical which allowed a defluorination reaction between perfluoroheptyl radical and hydroxyl radical/O2. Electrospray ionization (ESI) mass spectrum further confirmed that the oxidation of PFOA on the Ti/SnO2-Sb-Bi electrode proceeded from the carboxyl group in PFOA rather than C−C cleavage, and the decomposition processes followed the CF2 unzipping cycle. The electrochemical technique with the Ti/SnO2-Sb-Bi electrode provided a potential method for PFOA degradation in the aqueous solution.

Palladized foam nickel (Pd/Ni) catalyst was prepared by replacement deposition and employed to hydrodechlorinate 4-chlorophenol (4-CP) with formic acid (FA). 4-CP was rapidly transformed to phenol by means of hydrogenolysis. Major factors that may influence the 4-CP conversion rate, including the Pd loading amount, FA dosage, and solution pH value, were investigated. A moderate Pd loading amount (1.0 wt %), an excess of FA dosage (FA/4-CP ratio of 51.4:1), and a relatively low pH (4.0) were found to be the optimal operational conditions under which 4-CP was degraded up to 96.2% within 2 h and the catalytic activity of Pd/Ni reduced negligibly after three recycles. The dechlorination pathway is postulated as follows: (1) HCOOH (or HCOO−) decomposed on Pd particles with atomic hydrogen ([H]) generated; (2) [H] served as the direct reducing agent in the hydrodechlorination of 4-CP adsorbed on both Pd particles and Ni substrate, through the radical mechanism. Pd/Ni is found to be a promising catalyst in the elimination of organochlorines.

Eleven chlorobenzenes (CBs) in surface water and sediments of Tonghui River, a main urban drainage river of Beijing in China, were determined in October 2003, January 2004, and April 2006. CBs were widely detected and the ∑CB concentrations in water ranged from 89.9 to 6638.0 ng/L, with average values of 1902.8 ng/L in 2003, 2084.0 ng/L in 2004, and 1281.2 ng/L in 2006, respectively. The ∑CB concentrations in surficial sediments varied from 18.2 to 1827.7 ng/g dry weight (dw), with average values of 897.4 ng/g dw in 2003, 653.4 ng/g dw in 2004, and 562.6 ng/g dw in 2006, respectively. Nonparametric statistical analysis (Mann–Whitney U test) showed that there were no statistically significant changes in ∑CB concentrations in either surface water or sediments over the period 2003–2006. The distribution pattern of CBs in the Tonghui River indicates that further effort is warranted in reducing local sources of contaminants. Additionally, the ∑CB levels in sediment samples were found to be dependent on total organic carbon contents.

Perfluorooctane sulfonate (PFOS), as a potential persistent organic pollutant, has been widely detected in water environments, and has become a great concern in recent years. PFOS is very stable and difficult to decompose using conventional techniques. Sorption may be an attractive method to remove it from water. In this study, the molecularly imprinted polymer (MIP) adsorbents were prepared through the polymerization of 4-vinylpyridine under different preparation conditions in order to remove perfluorooctane sulfonate (PFOS) from water. The MIP adsorbents using perfluorooctanoic acid (PFOA) as the template had good imprinting effects and could selectively remove PFOS from aqueous solution. The sorption behaviors including sorption kinetics, isotherms, and effect of pH, salt, and competitive anions were investigated. Experimental results showed that the sorption of PFOS on the MIP adsorbents was very fast, pH-dependent, and highly selective. The achieved fast sorption equilibrium within 1 h was attributed to the surface sorption on the fine adsorbents. The sorption isotherms showed that the sorption selectivity of PFOS on the MIP adsorbents decreased at high PFOS concentrations, which may be due to the double-layer sorption and the formation of PFOS micelles on the sorbent surface. The sorption of PFOS on the MIP adsorbents was mainly dominated by the electrostatic interaction between the protonated vinylpyridine on the adsorbent surface and the anionic PFOS. The prepared MIP adsorbents can potentially be applied in water and wastewater treatment for selective removal of PFOS.

A new analytical method utilizing ultra-performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) has been developed to determine 16 pharmaceuticals from 8 therapeutic classes in wastewater: bezafibrate, clofibric acid, carbamazepine, caffeine, chloramphenicol, diclofenac, gemfibrozil, indomethacin, ketoprofen, mefenamic acid, metoprolol, nalidixic acid, N,N-diethyl-meta- toluamide, propranolol, sulpiride and trimethoprim. Key parameters of MS/MS, UPLC and solid phase extraction (SPE) were optimized. In general, recovery of target pharmaceuticals was over 70% for the wastewater effluent samples and 50% for the influent samples. The effects of matrix suppression, loss during the pretreatment as well as instrument variability were successfully corrected by two internal standards, and acceptable relative recovery was obtained. Target compounds were quantitatively analyzed using multiple reaction monitoring (MRM) mode, and the detection limits ranged from 0.3 to 20 ng/L. A detailed study, matrix effect in effluent wastewater was also present. The method was applied to detecting pharmaceuticals in the wastewater from three wastewater treatment plants (WWTPs) in Beijing, China and the results demonstrated that most target compounds were detectable in both the influent and effluent, with the mean concentrations ranging from 20.5 to 5775.6 ng/L and 4.6 to 418.6 ng/L, respectively.

A tiered approach consisting of several probabilistic options was used to refine aquatic ecological risk assessment (ERA) of individuals and mixture of various Organochlorine Pesticides (OCPs) detected in Jiangsu reach of Huaihe River, China. The tiered approach ranged from determined Hazard Quotient (HQ) to Joint Probability Curve and Monte Carlo simulation based HQ-distribution. The results from all levels of ERA methods in the tiered framework are consistent with each other. The results show that Endrin, o,p’-Dichloro-Diphenyl-Trichloroethane (DDT), α-Endosulfan and β-Endosulfan posed clear ecological risk; p,p’-DDT, p,p’-DDD, Aldrin, Heptachlorepoxide and Methoxychlor posed potential risk; while Hexachlorocyclohexanes, Heptachlor, Dieldrin and Hexachlorobenzene posed negligible risk. Further, based on the concept of total equivalent concentration, combined ecological risk caused by the mixture of all detected OCPs was calculated, and it proved to be significantly higher than the risk caused by any individual OCP. Despite inevitable uncertainties in current ERA, a comprehensive tiered approach can help to get a more credible result of risks of individuals and mixture of hazardous pollutants and screen the major risk pollutants contributing to the combined ecological risk.

In order to evaluate the electrocatalytic reduction performance of the refractory chlorinated organics in pure aqueous solution on palladium-modified electrode, this work studied several experimental variables of 2-chlorobiphenyl (2-ClBP) degradation on Pd/Ni foam electrode. The effects of monochlorobiphenyl congeners, the applied current densities, the pH, and the inorganic anions in the solution on the electrocatalytic reduction of 2-ClBP were investigated. 2-ClBP (or 3-ClBP) was more difficult to be reduced than 4-ClBP due to the effect of steric hindrance on Cl position at benzene ring. The optimized results showed that at an applied current density of 1.5 mA cm−2 and a weak acid condition of pH 5.6, 2-ClBP in water was reduced from 18.4 to 1.14 μM after 30 min electrolysis with consecutive hydrogenation. Biphenyl was the intermediate and cyclohexylbenzene was the final product with the concentration of 7.27 μM. On the basis of the XRD analysis and multiple electrolysis results, no significant change of the catalytic activity for 2-ClBP conversion on Pd/Ni foam electrode was observed. Additionally, inorganic anions such as SO42−, NO3−, and CO32− in water were able to slightly decrease the 2-ClBP conversion during multiple reactions, which are due to the redox sensitive characteristics of these anions. S2− ion in water was found to make the electrode deactivated due to the very weak adsorption of 2-ClBP on sulfided Pd electrode surface.

Quantitative structure–property relationship (QSPR) models were developed for soot–water partition coefficient (KSC) values of selected persistent organic pollutants (POPs), i.e. 10 polychlorinated dibenzo-p  -dioxins and dibenzofurans, nine polychlorinated biphenyls, four polycyclic aromatic hydrocarbons and two polybrominated diphenyl ethers, using partial least squares (PLS) regression. Quantum chemical descriptors computed by parameterized model revision 3 Hamiltonian method were used as predictor variables. The cross-validated Qcum2 value for the optimal QSPR model is 0.844, indicating a good predictive capability for the log KSC values of these chemicals. The QSPR results showed that average molecular polarizability (α), standard heat of formation (ΔHf) and energy of the lowest unoccupied molecular orbital (ELUMO) have dominant effects on KSC of POPs. The results suggested that log KSC values of POPs increase with the increase of α. Contrarily, log KSC values decrease with the increase of ELUMO and ΔHf of POPs.

Eighteen organochlorine pesticides (OCPs) were studied to develop species sensitivity distributions (SSDs) and calculate hazardous concentration thresholds for 5% of species (HC5), using both parametric (log-normal and log-logistic) and nonparametric bootstrap methods. In order to avoid picking repetitive values in each resample when performing bootstrap, and to determine the influence of fluctuation of toxicity data of single species on the SSDs and HC5, a modified bootstrap method was introduced, which can generate unrepetitive sampling data other than original elements in datasets. This method can enlarge a dataset without any assumption of a special distribution. Combined with parametric methods, modified bootstrap was also used to develop SSDs and determine HC5. The HC5 estimated by five approaches coincide well with each other with good positive correlation. Even if there is intra-species variation in a certain range of toxicity data; SSDs and HC5 are not very sensitive to the local fluctuation of toxicity of single species. The studied OCPs were classified according to their estimated HC5. A lower HC5 indicates higher ecological toxicity potentials. Endrin, DDTs and Endosulfan are OCPs with very high ecological toxicity potential. α-HCH has the lowest ecological toxicity potential in the studied OCPs. For OCPs with high ecological potential, more attention should be paid to their ecological risk.

As a party of the Stockholm Convention on Persistent Organic Pollutants, China must submit its national implementation plan (NIP) for this convention. The strategy and action plan for reducing the release of dioxins in China are the most important components of the NIP. Three problems are key points for developing such strategy and action plan—what are the key sources for applying the best available technology/best environmental practice (BAT/BEP) to reduce the release of dioxins? How about the capacity for reducing the dioxins release from the key sources? Where are the areas of priority for applying BAT/BEP? This paper shows the efforts towards the solution of these problems. The list of key sources covering about half of the total dioxins release was determined considering four criteria. The capacity of key sources were estimated based on the difference between the emission factor corresponding to the actual situation in 2004 and that corresponding to the scenario that all key sources have been applied BAT/BEP to reduce the dioxins release. The priority analysis using the geographical information system (GIS) tool has revealed that castern provinces should be of high priority in the future reduction activities of dioxins release in China.

A negligible depletion-solid phase microextraction (nd-SPME) method is developed to measure free concentrations of two alkyl phenols (4-t-octylphenol, nonylphenol) and bisphenol A in activated sludge, with which aerobic biodegradation kinetics of three pollutants was determined. For the degradation of octylphenol, nonylphenol and bisphenol A, the apparent rate constant based on total concentration is 0.02, 0.01 and 0.03 h−1, respectively; with the half life being 34.9, 54.3 and 22.3 h correspondingly. Meanwhile, real rate constants based on free concentration are 0.74, 0.60 and 1.03 h−1, respectively; with the half life being 0.9, 1.2 and 0.7 h accordingly. Differences between two constants revealed that desorption of targeted pollutants from activated sludge should be the rate-limiting step. Compared to the rapid biodegradation of alkyl phenols and bisphenol A in free state, the desorption of pollutants from the sludge is relatively slow, which made the apparent biodegradation rate constants much lower.

16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in water samples from the Jinsha River (Panzhihua part), Southwest China. Total dissolved PAH concentrations varied from 21.89 µg l−1 to 382.8 µg l−1. It was found that the concentration of PAHs decreased along the flow direction due to the higher density distribution of coal chemical industry in the upstream of our study rivers. The pollution levels in our study area are significantly higher than previously reported values in other waters both in China and other countries. The predominance of benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene was clearly observed in all water samples. On average these two compounds accounted for 98.3% of the total dissolved PAH concentration in water. The results showed the positive correlations among total dissolved PAHs, benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene, which suggested that these two predominant PAHs have similar source and environmental behaviors in our study area. When compared with the survey results of organic micropollutants two decades ago, it was found that hydrocarbon pollution both predominated and even increased with the development of coal chemical industry in this area during the past 20 years. The results therefore provide important information on the current contamination status of a key industrial city in China, and points to the need for urgent action to investigate the relationship between the PAH composition and concentration in water from the Jinsha River and the wastewater discharge from coal chemical industry, and to identify the source, transport pathway and fate of PAHs in the area. It should then be necessary to adopt appropriate and instant measures to control the pollution around this area.

Chemical’s persistence is known to be an important parameter applied for decades to identify persistent organic pollutants in hazard and/or risk assessments. Nevertheless it is greatly challenged in the case of emerging contaminants such as pharmaceuticals because the persistence of these chemicals could be more affected by environmental conditions. This fact brings more challenges to the current system for evaluating the persistence of chemical contaminants. In this paper, challenges in assessing the persistence of pharmaceuticals were identified, and more importantly research needs were addressed based on the existing data and knowledge.

This study mainly focused on the occurrence of pharmaceutical and personal care products (PPCPs) in sewage dewatered sludge and their discharges through sludge disposal from wastewater treatment plants (WWTPs). The data were obtained and calculated from seven PPCPs in dewatered sludge collected from 12 WWTPs in two typical cities, Beijing and Shenzhen in China. Four of seven PPCPs, diclofenac acid, carbamazepine, mefenamic acid and N,N-diethyl-m-toluamide were detectable in dewatered sludge from Beijing and Shenzhen with concentration up to 4240, 11,060, 92 and 219 μg/kg respectively. While, the other three compounds, trimethoprim, chloramphenicol and bezafibrate were not detected in collected samples from these two cities. The highest discharge of diclofenac acid and carbamazepine were 1023 g/d and 494 g/d respectively. In addition, the total discharge of these four detected PPCPs from each plant ranged from 5 to 1092 g/d in Beijing and 4–497 g/d in Shenzhen. Thus, PPCP discharge through sludge disposal cannot be neglected, and further research on transfer of PPCPs during sludge disposal onto agriculture land and influence of sludge application is required and essential.

The photodegradation of six individual PBDE congeners (BDE-28, 47, 99, 100, 153, 183) in hexane was investigated under UV light in the sunlight region, employing a mercury lamp filtered with Pyrex glass. All photodegradation reactions followed the pseudo-first-order kinetics, with the half-lives ranging from 0.26 h for BDE-183 to 6.46 h for BDE-100. The photochemical reaction rates of PBDEs decreased with decreasing number of bromine substituents in the molecule, also in some cases were influenced by the PBDE substitution pattern. Principal photoproducts detected were less brominated PBDEs, and no PBDE-solvent adducts were found. Consecutive reductive debromination was confirmed as the main mechanism for the photodegradation of PBDEs in hexane. In general, debromination firstly occurred on the more substituted rings, when the numbers of bromine atoms on the two phenyl rings were unequal. For less brominated PBDEs, the photoreactivity of bromines at various positions of phenyl rings decreased in the order: ortho > para; while for higher brominated PBDEs, the difference became not significant.

•We modeled biomonitoring data for PCBs and OCPs in the Australian population.•Reconstructed PCB intakes are lower and falling more rapidly in Australia than in the UK.•Intrinsic human elimination half-lives of PCBs and OCPs are 6.4 to 30 years.Quantifying the competing rates of intake and elimination of persistent organic pollutants (POPs) in the human body is necessary to understand the levels and trends of POPs at a population level. In this paper we reconstruct the historical intake and elimination of ten polychlorinated biphenyls (PCBs) and five organochlorine pesticides (OCPs) from Australian biomonitoring data by fitting a population-level pharmacokinetic (PK) model. Our analysis exploits two sets of cross-sectional biomonitoring data for PCBs and OCPs in pooled blood serum samples from the Australian population that were collected in 2003 and 2009. The modeled adult reference intakes in 1975 for PCB congeners ranged from 0.89 to 24.5 ng/kg bw/day, lower than the daily intakes of OCPs ranging from 73 to 970 ng/kg bw/day. Modeled intake rates are declining with half-times from 1.1 to 1.3 years for PCB congeners and 0.83 to 0.97 years for OCPs. The shortest modeled intrinsic human elimination half-life among the compounds studied here is 6.4 years for hexachlorobenzene, and the longest is 30 years for PCB-74. Our results indicate that it is feasible to reconstruct intakes and to estimate intrinsic human elimination half-lives using the population-level PK model and biomonitoring data only. Our modeled intrinsic human elimination half-lives are in good agreement with values from a similar study carried out for the population of the United Kingdom, and are generally longer than reported values from other industrialized countries in the Northern Hemisphere.Download full-size image

•F-53B and PFOS are synchronously used as mist suppressant in chrome plating industry.•IRA67 shows higher adsorption velocity and capacity for PFOS than F-53B.•IRA67 shows high adsorption capacities of F-53B and PFOS at low pH.•IRA67 is successfully regenerated by NaOH/NaCl and CH3OH mixed solution.•IRA67 can remove F-53B and PFOS in wastewater without obvious preference.Chrome plating is an important emission source of perfluorinated compounds (PFCs) industrial uses in China, where two commercial products potassium 2-(6-chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyloxy) (F-53B) and perfluorooctane sulfonate (PFOS) are applied as mist suppressant, causing non-negligible environmental risk. In this paper, anion-exchange resin IRA67 was evaluated for F-53B and PFOS removal from simulated and actual wastewater. Adsorption kinetics exhibited higher adsorption velocity and capacity of IRA67 for PFOS than F-53B due to their difference in molecular structures. Adsorption isotherms demonstrated the adsorption capacity of F-53B and PFOS on IRA67 was 4.2 mmol/g and 5.5 mmol/g, respectively. Because of the deprotonating of amine groups, solution pH had significant effect on IRA67 at pH > 10. The results indicated that besides anion exchange other interactions including hydrophobic interaction and the formation of micelles or hemi-micelles were all involved in adsorption process. Coexisting sulfate and chromate in wastewater decreased adsorption capacities of F-53B and PFOS. The spent resin could be regenerated by the NaCl/NaOH and methanol mixed solution. In the mixed system and actual wastewater IRA67 can simultaneously remove F-53B and PFOS without obvious preference but the removal percent can be affected by competitive effect.Download high-res image (108KB)Download full-size image

The photolysis of 16 poly chlorinated biphenyls (PCBs) (including mono-through deca-chlorinated) in “-hexane was investigated under ultraviolet irradiation using a 500-W high-pressure mercury lamp. Photolysis of PCBs follows pseudo-first-order reaction kinetics, with photolysis rate constants ranging between 0.0011 s−1 for PCB-52 and 0.0574 s−1 for PCB-118. The degradation rates of PCBs by high-pressure mercury lamp irradiation were remarkably independent with respect to the degree of chlorination. Furthermore, partial least squares (PLS) models were developed to provide insight into which aspect of the molecular structure influenced PCB photolysis rate constants. It was found that the photolysis rates of PCBs increased with an increase in the net charge on the carbon atom (qc), (Elumo-Ehomo)2, and the Y-axis dipole moment (μy) values, or the decrease in the energy of the second highest occupied molecular orbital (Ehomo-1), energy of the lowest unoccupied molecular orbital (Elumo), Elumo + Ehomo, Elumo - Ehomo, most positive atomic charge (q+), and the twist angle of the chlorine atom (TA) values.