•The KOA values for 14 OPFRs were determined by GC retention time method.•Substitution pattern and VM were found to be capable of influencing log KOA-GC values of OPFRs.•Log KOA-GC values of the remaining OPFRs can be predicted by using their RRTs.Organophosphate flame retardants (OPFRs) have attracted wide concerns due to their toxicities and ubiquitous occurrence in the environment. In this work, Octanol-air partition coefficient (KOA) for 14 OPFRs including 4 halogenated alkyl-, 5 aryl- and 5 alkyl-OPFRs, were estimated as a function of temperature using a gas chromatographic retention time (GC-RT) method. Their log KOA-GC values and internal energies of phase transfer (ΔOAU/kJ mol−1) ranged from 8.03 to 13.0 and from 69.7 to 149, respectively. Substitution pattern and molar volume (VM) were found to be capable of influencing log KOA-GC values of OPFRs. The halogenated alkyl-OPFRs had higher log KOA-GC values than aryl- or alkyl-OPFRs. The bigger the molar volume was, the greater the log KOA-GC values increased. In addition, a predicted model of log KOA-GC versus different relative retention times (RRTs) was developed with a high cross-validated value (Q2(cum)) of 0.951, indicating a good predictive ability and stability. Therefore, the log KOA-GC values of the remaining OPFRs can be predicted by using their RRTs on different GC columns.

•Photo-active species generated from three metal oxide–silica nanocomposites suspension were investigated.•The amount of active species (OH, O2−, 1O2 and e−) varied with different nanocomposites.•CuO–SiO2 exhibited most obviously photocatalytic activity toward degradation of bisphenol A, and followed by Fe2O3–SiO2 and ZnO–SiO2.Metal oxide nanocomposites with photocatalytic activity have the potential for many applications in environmental remediation and biomedicine. In this study, we investigated the formation and stabilization of electrons/holes from three metal oxide–silica nanocomposites (CuO–SiO2, Fe2O3–SiO2 and ZnO–SiO2) under irradiation by electron paramagnetic resonance (EPR) technology. The characteristic EPR signals with g = 2.00070–2.00105, ΔHp-p = 2.17–2.37 G were determined, which corresponded to lattice-trapped electrons. Moreover, the generation of active species from CuO–SiO2, Fe2O3–SiO2 and ZnO–SiO2 in aqueous solution under irradiation was also systematically studied. The results showed that all the three nanocomposites could generate hydroxyl radical, singlet oxygen and electron. CuO–SiO2 was more effective than Fe2O3–SiO2 and ZnO–SiO2 in producing hydroxyl radical and electrons, while ZnO–SiO2 was the most efficient in generating singlet oxygen. In addition, CuO–SiO2 exhibited most obviously photocatalytic activity toward degradation of bisphenol A, followed by Fe2O3–SiO2 and ZnO–SiO2. These findings will provide vital insights into photocatalytic mechanisms and potentially photoinduced toxicity of metal oxide–silica nanocomposites.

Little information is available about the bioaccumulation and biomagnification of antibiotics in marine food webs. Here, we investigate the levels and trophic transfer of 9 sulfonamide (SA), 5 fluoroquinolone (FQ), and 4 macrolide (ML) antibiotics, as well as trimethoprim in nine invertebrate and ten fish species collected from a marine food web in Laizhou Bay, North China in 2014 and 2015. All the antibiotics were detected in the marine organisms, with SAs and FQs being the most abundant antibiotics. Benthic fish accumulated more SAs than invertebrates and pelagic fish, while invertebrates exhibited higher FQ levels than fish. Generally, SAs and trimethoprim biomagnified in the food web, while the FQs and MLs were biodiluted. Trophic magnification factors (TMF) were 1.2–3.9 for SAs and trimethoprim, 0.3–1.0 for FQs and MLs. Limited biotransformation and relatively high assimilation efficiencies are the likely reasons for the biomagnification of SAs. The pH dependent distribution coefficients (log D) but not the lipophilicity (log KOW) of SAs and FQs had a significant correlation (r = 0.73; p < 0.05) with their TMFs. Although the calculated estimated daily intakes (EDI) for antibiotics suggest that consumption of seafood from Laizhou Bay is not associated with significant human health risks, this study provides important insights into the guidance of risk management of antibiotics.

In this study, the occurrence and removal efficiencies of 31 antibiotics, including 11 sulfonamides (SAs), five fluoroquinolones (FQs), four macrolides (MLs), four tetracyclines (TCs), three chloramphenicols (CAPs), and four other antibiotics (Others), were investigated in 12 municipal wastewater treatment plants (WWTPs) in Dalian, China. A total of 29 antibiotics were detected in wastewater samples with the concentration ranging from 63.6 to 5404.6 ng/L. FQs and SAs were the most abundant antibiotic classes in most wastewater samples, accounting for 42.2 and 23.9% of total antibiotic concentrations, respectively, followed by TCs (16.0%) and MLs (14.8%). Sulfamethoxazole, erythromycin, clarithromycin, azithromycin, ofloxacin, and norfloxacin were the most frequently detected antibiotics; of these, the concentration of ofloxacin was the highest in most of influent (average concentration = 609.8 ng/L) and effluent (average concentration = 253.4 ng/L) samples. The removal efficiencies varied among WWTPs in the range of −189.9% (clarithromycin) to 100% (enoxacin, doxycycline, etc), and more than 50% of antibiotics could not be efficiently removed with the removal efficiency less than 65%. An environmental risk assessment was also performed in the WWTP effluents by calculating the risk quotient (RQ), and high RQ values (>1) indicated erythromycin and clarithromycin might cause the ecological risk on organisms in surrounding water near discharge point of WWTPs in this area, which warrants further attention.

•The serum levels of 7 PBDEs, 11 OH-PBDEs, and thyroid function were examined.•BDE-47, 6-OH-BDE-47, and 3-OH-BDE-47 were the predominant congeners.•The associations between PBDEs and thyroid function were not significant.•3-OH-BDE-47 was inversely correlated with FT4.•4'-OH-BDE-49 and ΣOH-PBDEs were significantly and positively associated with TSH.Polybrominated diphenylethers (PBDE) have been demonstrated to be associated with significant alterations in hormone levels in humans. However, yet few epidemiological human evidence has associated thyroid function with hydroxylated polybrominated diphenylethers (OH-PBDEs), which may be more potent in disrupting thyroid hormone homeostasis. In the present study, the body burdens of 7 PBDEs and 11 OH-PBDEs as well as the serum thyroid status were examined in a cohort of 33 thyroid cancer patients. The levels of ∑PBDEs and ∑OH-PBDEs ranged from 1.07 to 39 ng/g lipid, and 0.01–0.46 ng/g lipid, respectively. BDE-47, 6-OH-BDE-47 and 3-OH-BDE-47 were the predominant congeners. The associations between these PBDE congeners and thyroid function were not significant after controlling for sociodemographic characteristics, as well as the associations between OH-PBDEs and free T3. There were an inverse association between lg3-OH-BDE-47 and lgFT4 (free T4) but a positive association between lg4'-OH-BDE-49 and TSH. Both lgΣ5OH-PBDEs (the sum of HO-tetra-BDEs) and lgΣOH-PBDEs were significantly and positively associated with lgTSH. Our results are consistent with most human studies, suggesting that OH-PBDEs can alter thyroid function by enhancing the elimination of serum FT4 with elevated TSH levels. To our knowledge, this is the first study to examine and report associations between OH-PBDEs and thyroid function in a cancer population.

•Serum levels of 40 antibiotics were determined in 107 normal adults.•28 antibiotics were detected and 5 were above 1000 ng/mL in 3.7% of the samples.•Males had higher levels of the veterinary antibiotics than females (p < 0.05).•There were significant BMI-related and age-related differences for sulfonamides.•No health risks occurred except for azithromycin in one sample.Recently, increasing regulatory and public attention has been paid to the exposure risks of antibiotics due to their occurrence and antibiotic resistance worldwide. However, limited information on antibiotic levels in general populations is available. Forty antibiotics, including 9 sulfonamides, 5 fluoroquinolones, 4 macrolides, 4 tetracyclines, 3 chloramphenicols, 12 β-lactams and 3 others, were analyzed in 107 serum samples of normal adults collected from a hospital in Dalian, North China, between 2015 and 2016 using solid-phase extraction (SPE) coupled with HPLC-MS/MS. The results clearly showed that antibiotics were present in the serum of these adults. Specifically, 28 antibiotics were detected in the samples, with detection frequencies ranging from 0.9% to 17.8%. The total antibiotic concentrations in 26.2% of the serum samples were between the LOD and 20.0 ng/mL. Importantly, the maximum concentrations of 5 antibiotics (trimethoprim, ciprofloxacin, cefaclor, lincomycin and erythromycin) were above 1000 ng/mL in 3.7% of the samples. Furthermore, the detection frequencies of 5 veterinary antibiotics, 7 human antibiotics and 16 human/veterinary antibiotics in the serum samples were 23.4%, 17.8% and 29.0%, respectively. Significant differences of the veterinary antibiotics between female and male adults and of the sulfonamides between different BMI (body mass index) groups were observed (p < 0.05). The concentrations of sulfonamides in elderly individuals were significantly higher (p < 0.05) than those in young people. Finally, our results showed that almost all of the adults had no health risks related to exposure to antibiotics at such levels despite the high effect ratio (ER = 1.74) for azithromycin in one sample. This study is the first to report the current status of antibiotics in human blood, which can help in better understanding the long-term effects of antibiotics on general populations and in identifying susceptible populations that are at high risk to antibiotic exposure.Download high-res image (87KB)Download full-size image

Hydroxylated polybromodiphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are emerging organic pollutants. Supercooled liquid vapor pressures (pL) and enthalpies of vaporization (∆vapH) for seventeen OH-PBDEs and eleven MeO-PBDEs were determined by a gas chromatographic technique. pL at 298 K ranged from 0.0173 Pa for 2′-OH-BDE3 to 2.32 × 10−7 Pa for 3′-OH-BDE154 and they are approximately one order of magnitude smaller than those determined for the counterpart polybrominated diphenyl ethers (PBDEs). ∆vapH was in the range of 76–121 kJ/mol. The temperature dependence of pL was measured by fitting the experimental data with the log(pL/Pa) = a/(T/K) + b equation, and this corresponds to a 50–265 times higher pL value at 0 versus 30°C. Using fundamental quantum chemical descriptors, two quantitative structure–property relationship models (Qcum > 0.935) were developed to estimate pL at any temperature for the additional OH- and MeO-PBDE congeners.

Hydroxylated polybromodiphenyl ethers (OH-PBDEs) are emerging aquatic pollutants, but their origins in the environment are not fully understood. There is evidence that OH-PBDEs are formed from bromophenols, but the underlying transformation processes remain unknown. Here, we investigate if the photoformation of OH-PBDEs from 2,6-dibromophenol in aqueous solution involves 2,6-bromophenoxyl radicals. After the UV irradiation of an aqueous 2,6-dibromophenol solution, HPLC–LTQ-Orbitrap MS and GC–MS analysis revealed the formation of a OH-PBDE and a dihydroxylated polybrominated biphenyl (di-OH-PBB). Both dimeric photoproducts were tentatively identified as 4′-OH-BDE73 and 4,4′-di-OH-PBB80. In addition, three debromination products (4-OH-BDE34, 4′-OH-BDE27, and 4,4′-di-OH-PBBs) were observed. Electron paramagnetic resonance spectroscopy revealed the presence of a 2,6-dibromophenoxyl radical with a six-line spectrum (aH (2 meta) = 3.45 G, aH (1 para) = 1.04 G, g = 2.0046) during irradiation of a 2,6-dibromophenol solution in water. The 2,6-dibromophenoxyl radical had a relatively long half-life (122 ± 5 μs) according to laser flash photolysis experiments. The para–para C–C and O–para-C couplings of these 2,6-dibromophenoxyl radicals are consistent with the observed formation of both dimeric OH-PBDE and di-OH-PBB photoproducts. These findings show that bromophenoxyl radical-mediated phototransformation of bromophenols is a source of OH-PBDEs and di-OH-PBBs in aqueous environments that requires further attention.

•7 PBDEs and 11 OH-BDEs were examined in 32 female serum samples from Dalian, China.•BDE-47 and 3-HO-BDE-47 were their corresponding predominant congeners.•Significant relationships were found between BDE-47 and its three metabolites.Seven polybrominated diphenyl ethers (PBDEs) and eleven hydroxylated PBDEs (OH-PBDEs) were selected to investigate their contamination status in 32 female serum samples from Dalian, China. These studied PBDEs and OH-PBDEs were found in most of the serum samples with the concentrations of ΣPBDEs and ΣOH-PBDEs ranging from 1.07 to 38.7 ng/g lipid (median: 5.56 ng/g lipid) and from 0.011 to 0.436 ng/g lipid (median: 0.069 ng/g lipid), respectively. More impressively, BDE-47 and OH-BDE-47 were the predominant congeners in female serum, accounting for 52% of ΣPBDEs and 46% of ΣOH-PBDEs, respectively. Correspondence analysis indicated that significant (p < 0.05) positive correlations were observed between BDE-47 and its metabolites such as 6-OH-BDE-47, 3-OH-BDE-47 and 4′-OH-BDE-49. In addition, the positive significant (p < 0.05) correlation was shown between ∑PBDEs and lipid contents but between concentrations of ∑PBDEs and ages or BMIs, as well as for ∑OH-PBDEs.

The octanol–air partition coefficient (KOA) of 19 hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and 10 methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were measured as a function of temperature using a gas chromatographic retention time technique. At room temperature (298.15 K), log KOA ranged from 8.30 for monobrominated OH/MeO-PBDEs to 13.29 for hexabrominated OH/MeO-PBDEs. The internal energies of phase change from octanol to air (ΔOAU) for 29 OH/MeO-PBDE congeners ranged from 72 to 126 kJ mol−1. Using partial least-squares (PLS) analysis, a statistically quantitative structure–property relationship (QSPR) model for log KOA of OH/MeO-PBDE congeners was developed based on the 16 fundamental quantum chemical descriptors computed by PM3 Hamiltonian, for which the Qcum2 was about 0.937. The molecular weight (Mw) and energy of the lowest unoccupied molecular orbital (ELUMO) were found to be main factors governing the log KOA.

•Twenty-five antibiotics in the coastal water of Yancheng were measured.•Antibiotics were widely present with the highest level up to 1349.2 ng/L.•DOC, salinity and distance were important in the fate and residues of antibiotics.•The attenuation of antibiotics was faster in this region than in Bohai Sea.•Individual antibiotic could pose low risk, while the mixture might pose high risk.The occurrence and distribution of 25 antibiotics from 5 categories in Yancheng coastal area of the South Yellow Sea were investigated using solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry. Results showed that these antibiotics were widely present in this region with the total concentration up to 1349.2 ng/L. Fluoroquinolones and sulfonamides were the most abundant categories contributing 46.5%, and 21.4% to the total antibiotics burden. Trimethoprim was the antibiotic detected in all the samples. The detection rates of erythromycin-H2O, sulfamethoxazole and florfenicol were 70.0%, 56.7% and 53.4%, respectively. The distribution of antibiotics demonstrated a seaward decreasing trend with the attenuation rate ranging from 0.07 to 0.19 km− 1 in this region. Log total antibiotic concentrations was significantly correlated with DOC (dissolved organic carbon) contents, salinity and distance from the coast (p < 0.05), which indicated the vital effect of these factors on the transport and fate of antibiotics. Risk assessment revealed that individual antibiotic could mainly pose a low to medium ecological risk, while the risk of antibiotic mixture on aquatic organisms needed further investigation.Download high-res image (223KB)Download full-size image

•Twenty-five antibiotics in the coastal water of Yancheng were measured.•Antibiotics were widely present with the highest level up to 1349.2 ng/L.•DOC, salinity and distance were important in the fate and residues of antibiotics.•The attenuation of antibiotics was faster in this region than in Bohai Sea.•Individual antibiotic could pose low risk, while the mixture might pose high risk.The occurrence and distribution of 25 antibiotics from 5 categories in Yancheng coastal area of the South Yellow Sea were investigated using solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry. Results showed that these antibiotics were widely present in this region with the total concentration up to 1349.2 ng/L. Fluoroquinolones and sulfonamides were the most abundant categories contributing 46.5%, and 21.4% to the total antibiotics burden. Trimethoprim was the antibiotic detected in all the samples. The detection rates of erythromycin-H2O, sulfamethoxazole and florfenicol were 70.0%, 56.7% and 53.4%, respectively. The distribution of antibiotics demonstrated a seaward decreasing trend with the attenuation rate ranging from 0.07 to 0.19 km− 1 in this region. Log total antibiotic concentrations was significantly correlated with DOC (dissolved organic carbon) contents, salinity and distance from the coast (p < 0.05), which indicated the vital effect of these factors on the transport and fate of antibiotics. Risk assessment revealed that individual antibiotic could mainly pose a low to medium ecological risk, while the risk of antibiotic mixture on aquatic organisms needed further investigation.Download high-res image (223KB)Download full-size image