Polychlorinated biphenyls in the atmosphere of Taizhou,a major e-waste dismantling area in China

PM2.5, total suspended particles （TSP） and gas phase samples were collected at two sites of Talzhou, a major e-waste dismantling area in China. Concentrations, seasonal variations, congener profiles, gas-particle partitioning and size distribution of the atmospheric polychlorinated biphenyls （PCBs） were studied to assess the current state of atmospheric PCBs after the phase out of massive historical dismantling of PCBs containing e-wastes. The average ∑38PCBs concentration in the ambient air （TSP plus gas phase） near the e-waste dismantling area was （12,407 ± 9592） pg/m^3 in winter, which was substantially lower than that found one decade ago. However, the atmospheric PCBs level near the e-waste dismantling area was 54 times of the reference urban site, indicating that the impact of the historical dismantling of PCBs containing e-wastes was still significant. Tri-Penta-CBs were dominant homologues, consisting with their dominant global production. Size distribution of particle-bound PCBs showed that higher chlorinated CBs tended to partition more to the fine particles, facilitating its long range air transportation.

Levels and distributions of polychlorinated biphenyls in sewage sludge of urban wastewater treatment plants

Concentrations of polychlorinated biphenyls （PCBs） have been measured in sewage sludge samples from 8 urban wastewater treatment plants in Beijing, China. The PCB congeners were analyzed by isotope dilution high resolution gas chromatography/high resolution mass spectrometry method. The concentration of PCBs ranged from 65.6 to 157 ng/g dry weight （dw）, with a mean value of 101 ng/g dw. The dioxin-like PCB WHO-TEQs （World Health Organization-Toxic Equivalents） of the sludge were lower than 1 pg /g dw. Consequently, all the concentrations of PCBs in sludge samples were below the upper limit for land application according to the Chinese legislation law for agriculture use. The PCB homologue profiles in sludge samples were dominated by tri-CBs and tetra- CBs. Similar distributions have been found in one of the Chinese PCB commercial products. The patterns of dioxin-like and indicator congeners observed in this study were quite similar in all samples. The predominant congener for dioxin-like and indicator PCBs were PCB-118 and PCB-28, respectively, while PCB-126 had the highest TEQ value.

A QSRR Study on the Chromatographic Retention Indices of Hydroxylated Polychlorinated Biphenyls

Hydroxylated Polychlorinated Biphenyls （HO-PCBs） are the metabolite of polychlorinated biphenyls and have drawn much attention because they have hazard on human health and ecosystems. Molecular connectivity index calculation has been performed for 19 HO-PCB compounds. A number of statistically based parameters have been extracted. Linear relationship between chromatographic retention index （RI） and the molecular connectivity index of 15 compounds in the training set has been established by multiple linear regression method. The other 4 HO-PCBs are used as the external test set. The result shows that the parameters can be well used to express the quantitative structure-retention relationship （QSRR） of HO-PCBs. Good stability and predictive ability have been demonstrated by leave-one-out cross-validation and the external test set.

Surface Electrostatic Potentials of Polychlorinated Dibenzo-p-dioxins and Their Applications in the Quantitative Structure-properties Relationships

Polychlorinated dibenzo-p-dioxins（PCDDs） are a group of important persistent organic pollutants.They are highly toxic and persistent in environment.In the present study,geometrical optimization and electrostatic potential calculations have been performed for 75 PCDD congeners and dibenzo-p-dioxin（DD） at the HF/6-31G＊ level of theory.A number of statistically based parameters have been extracted.Linear relationships between vapor pressures（logpL）,aqueous solubilities（logSw）,n-octanol/water partition coefficients（logKow） of PCDDs and structural descriptors have been established by stepwise linear regression analysis.The result shows that the quantities derived from the surface electrostatic potentials Vmin,Π,and Vs,av＋,together with Vmc（the molecular volume） and ELUMO（the energy of the lowest unoccupied molecular orbital） can be well used to express the quantitative structure-property relationships of PCDDs.Predictive capabilities of the models have also been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient（Rcv） above 0.97.Based on these QSPR models,the predicted values have been presented for those PCDD congeners whose experimentally determined physicochemical properties are unavailable.

Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Fluorenes

Geometric structures of 135 polychlorinated fluorene （PCFR） molecules were optimized using density functional theory （DFT） at the B3LYP/6-311G＊＊ level and their thermodynamic properties in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCFR congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation （Δr,fGθ）. The results show that the geometric configuration of PCFR isomers is determined by the position of chlorine atoms. There exist two types of intramolecular weak interactions, i.e., C–H···Cl and Cl···Cl interactions in PCFR molecules. The change of ΔfHθ and ΔfGθ of most stable PCFR isomers with increasing the number of chlorine atoms is different from that in most unstable PCFR congeners. The values of ΔfHθ and ΔfGθ for PCFR isomers with the same number of chlorine atoms strongly depend on the position of chlorine atoms and the relative stability of PCFR congeners is mainly determined by intramolecular delocalized π bond and Cl···Cl nuclear repulsive interaction.

Development and characterization of new polyclonal antibodies specific for three polychlorinated biphenyls

Three polychlorinated biphenyls （PCBs） congeners and their corresponding haptens bearing four carbon length carboxylic groups that can be linked to a protein for raising antibodies were synthesized. The three resultant immunogens were fabricated and used to stimulate immune responses in rabbits to survey the characteristics of the haptens. Three of the resultant polyclonal antibodies （Pabs） were obtained. The antiserum exhibited relatively high antibody titres （1：32-64） in double agar diffusion.

Estimation of Aqueous Solubility (-lgS_w) of All Polychlorinated Biphenyl (PCB) Congeners by Density Functional Theory and Position of Cl Substitution (NPCS) Method

Optimization calculations of 209 polychlorinated biphenyls （PCBs） were carried out at the B3LYP/6-31G^＊ level. It was found that there is significant correlation between the Cl substitution position and some structural parameters. Consequently, Cl substitution positions were taken as theoretical descriptors to establish a novel QSPR model for predicting –lgSw of all PCB congeners. The model achieved in this work contains four variables, of which r^2 = 0.9527, q^2 = 0.9490 and SD = 0.25 with large t values. In addition, the variation inflation factors （VIFs） of variables in this model are all less than 5.0, suggesting high accuracy of the –lgSw predicting model. And the results of cross-validation test and method validation also show that the model exhibits optimum stability and better predictive capability than that from the AM1 method.

Levels of polychlorinated biphenyls in 1,4-dichlorobenzene mothballs

Although polychlorinated biphenyls(PCBs) are globally recognized pollutant, an understanding of their resources as by products in chemical industry is poorly investigated. This paper presents data from a study that was conducted in order to determine the extent of PCBs in 1,4 dichlorobenzene( p DCB) mothballs. Total PCBs and dioxin like PCBs were detected in five mothball samples. Total PCB concentrations ranged from 328 ng/g to 1798 ng/g, while the levels of WHO TEQ were between 0 16 pg/g and 13 pg/g. Mean concentrations of total PCBs and WHO TEQ in the samples were 724 ng/g and 3.2 pg/g, respectively. The highest level of PCB congeners was that of trichlorinated biphenyls(537 ng/g), which maybe due to the relatively low chlorination in the process of p DCB production. A mechanism of the formation of PCBs from polychlorinated benzene in the presence of chlorine is also suggested. The results suggested that re estimation on the risk of p DCB products, especially the products for daily use such as mothballs, is expected.

Effect of polychlorinated biphenyls on spermatogenesis and testosterone secretion in adult cocks

The effects ofpolychlorinated biphenyls (PCBs) on reproduction of adult cocks were studied by gavaging peanut oil or PCBs (Aroclor 1254, 50 mg/kg) once a week for six consecutive weeks. Physiological parameters were recorded and gonads were removed at the end of experiment for histological examination. The results showed that there was no significant difference between the control and treatment group in body weight, respiration rate, heart rate, body temperature, and the numbers of red and white blood cells. However, there was a marked decrease in the testicular weight and serum testosterone level after PCB treatment. Morphological studies manifested severe damage of the seminiferous tubules by PCB. The number of the germ cells at the different developmental stages was decreased and condensed nuclei were observed in most of these cells. This study revealed that the reproductive function of the adult cocks is sensitive to PCBs, which inhibited mainly spermatogenesis and testosterone secretion.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in flue gas emissions from municipal solid waste incinerators in China

Polychlorinated dibenzo-p-dioxins and furans （PCDD/Fs） emissions in flue gas from two types of municipal solid waste incinerators （MSWIs） most commonly used in China were investigated in this study. The selected incinerators include two grate-type MSWIs： MSWI-A （350 t/d） and MSWI-B 050 t/d）, and two fluidized bed MSWIs： MSWI-C （400 t/d） and MSWI-D （400 t/d）, which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber （WS） as air pollutant control device （APCD）. Results indicated that the emission concentration and the international toxic equivalents （I-TEQs） of the PCDD/Fs from the stacks were in the range of 1.210-10.273 ng/Nm^3 and 0.019-0.201 ng I-TEQ/Nm^3, respectively. They were greatly lower than the emission regulation standard of PCDD/Fs in China （1.0 ng I-TEQ/Nm^3）. However, only the PCDD/Fs emission level from MSWI-C was below 0.1 ng I-TEQ/Nm^3. Although the homologue profiles were distinct, the contributions of the 2,3,7,8-subsituted congeners to the total I-TEQ were similar among all the investigated MSWIs. Two major 2,3,7,8-substituted congeners, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD, account for 47% and 9% （average values） of the total I-TEQ values, respectively. The correlation between PCDD/Fs levels and composition of flue gas was also discussed.

Spatial Distribution of Polychlorinated Biphenyls(PCBs)Contaminants in the Tidal-flat Sediments of Yangtze Estuary

PCBs pollutants are measured on tidal-flat sediments of Yangtze estuary by a high resolution capillary column gas chromatography ( HP6890 ) equipped with an 63Ni electron capture detector ( ECD ). The concentration tendency of PCBs is Phragmites zone > Scirpus zone > bare mudflats. There are linear relations between PCBs and TOC and > 63μm grain size percentage ( in volume ). The low chlorinated congeners may be more important than the high chlorinated congeners in this area. PCBs prefer to accumulate in the sediments near sewage outlets and Phragmites zone. The sediments’ PCBs pollution ( 10.7 ~ 28.6 ng/g, dry weight ) in the Yangtze estuary tidal-flat is less serious than that of the most of other areas in the world .But the detected ratio is 100%, even the Jiuduansha shoal has detected PCBs, so much attention should be paid to this area for PCBs.

Three-dimensional Holographic Vector of Atomic Interaction Field(3D-HoVAIF) for the QSPR/QSAR of Polychlorinated Naphthalenes

Three-dimensional holographic vector of atomic interaction field（3D-HoVAIF） is used to describe the chemical structures of polychlorinated naphthalenes（PCNs）.After variable screening by stepwise multiple regression（SMR） technique,the liner relationships between gas-chromatographic relative retention time（RRT）,298 K supercooled liquid pressures（logPL）,n-octanol/air partition coefficient（logKOA）,n-octanol/water partition coefficient（logKOW）,aqueous solubilities（logSW）,relative in vitro potency values（-logEROD） of PCNs and 3D-HoVAIF descriptors have been established by partial least-square（PLS） regression.The result shows that the 3D-HoVAIF descriptors can be well used to express the quantitative structure-property（activity） relationships of PCNs.Predictive capability of the models has also been demonstrated by leave-one-out cross-validation.Moreover,the predicted values have been presented for those PCNs which are lack of experimentally physico-chemical properties and biological activity by the optimum models.

Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Acenaphthylenes

Geometric structures of 135 polychlorinated acenaphthylene （PCAC） molecules were optimized using density functional theory （DFT） at the B3LYP/6-311G^＊＊ level and some thermodynamic properties of them in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCAC congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation （△r,fGθ）. The results show that all PCAC isomers have planar geometric configuration. There exists intramolecular Cl···Cl weak interaction in some PCAC molecules. The change of △fHθ and fGθ of most stable PCAC isomers with increasing the number of chlorine atoms is different from that in the least stable PCAC congeners. The values of fHθ and fGθ for PCAC isomers with the same number of chlorine atoms show a strong dependence on the position of chlorine atoms and the relative stability of PCAC congeners has close relation with the intramolecular Cl···Cl nuclear repulsive interaction.

Prediction of the Aqueous Solubilities of Polychlorinated Biphenyls

Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the aqueous solubilities of polychlorinated biphenyls (PCBs) were predicted. A three-variable regression equation with correlation coefficient of 0.9739 and the root mean square errors of 0.26 was developed. The descriptors included in the equation represent three interactions between three pairs of atomic types, i.e., atom -C= and >C=, -C= and -Cl, and -Cl and -Cl. It has been proved that the aqueous solubilities of 137 PCB congeners can be accurately predicted as long as there are more than 65 calibration compounds.

Prediction of Aqueous Solubility for 209 Polychlorinated Diphenyl Ethers from Molecular Structural Parameters by DFT Method

Optimized calculations of 209 polychlorinated diphenyl ethers （PCDEs） and diphenyl ethers were carried out at the B3LYP/6-31G^＊ level with the Gaussian 98 program. Based on the theoretical linear solvation energy relationship （TLSER） model, the obtained structural parameters were taken as theoretical descriptors to establish the novel QSPR model for predicting aqueous solubility （-lgSw） of PCDEs. The model obtained in this work contains two variables： mean molecular polarizability （a） and the most positive partial charge on a hydrogen atom （qH^＋）, of which RE = 0.9606 and SD = 0.32. And the results of cross-validation test also show that the model exhibits optimum stability and better predictive power. Moreover, the predictive power of the new model is better than that of MCIs method.

Polychlorinated Biphenyls Contamination of Sludge in India

Polychlorinated Biphenyls (PCBs) exist in all compartments of the ecosystem due to wide industrial applications and production during burning processes. The PCBs congeners were quantified in the industrial, municipal and agricultural wastes of the most industrialized area of the country, Raipur city, India. The concentration of ΣPCBs in the sludge, sewage and agriculture wastes (n = 4) was ranged from 497 - 800 μg/kg with mean value of 634 ± 146 μg/kg. The PCBs congeners detected in the waste materials were ranged from 56 - 85 with mean value of 75 ± 13. The highest number of congeners was quantified in the sludge materials due to the existence of the heavy PCBs. The PCBs congeners were found to decrease vertically due to the adsorption by the geo-media. The distribution, sources and toxicities of PCBs congeners in the waste materials are discussed.

Polystyrene nanoplastics aggravated ecotoxicological effects of polychlorinated biphenyls in on zebrafish(Danio rerio)embryos

In view of the accumulation of nanoplastics(NPs)in the food chain of environment and animals,and the good adsorption properties of nano-plastics to toxic substances,it is necessary to explore the influence of NPs in living organisms.In this study,single and joint toxicological effects of polystyrene nanoplastics(PS-NPs,size 80 nm)and polychlorinated biphenyls(PCBs),were explored in freshwater aquatic animal model zebrafish(Danio rerio).Our study found that exposure to single PS-NPs induced mild acute toxicity,albeit the combined exposure of PS-NPs and polychlorinated biphenyls aggravated the toxicity of PCBs in a dose-dependent manner.Results from gene expression profiling showed that NPs exposure could activate detoxification process,resulting in a slight up-regulation of antioxidant genes(sod1,gstp1),bone development genes(bmp2,bmp4)and cardiac gene(tbx20);while PCBs suppressed the detoxification through down-regulation of these genes,and the addition of NPs will exacerbate the impact of PCBs on gene suppression.Importantly,the results of in vivo purification experiments found that NPs showed prolonged retention in liver,intestine and gills of zebrafish and they might have crossed biological barrier and accumulate in lipid-rich tissues and excretion does not appear as the significant pathway for their elimination.In conclusion,the toxic effects of polychlorinated biphenyls on chorionic protected embryos were not significant as zebrafish chorion plays an important role in resisting the invasion of pollutants;PCBs can seriously damage the bone and heart development of zebrafish,while the presence of NPs significantly enhanced the toxicity of PCBs in zebrafish,which is an alarming concern for growing NPs levels and ecological safety in aquatic environment.

Studies of Structural and Thermodynamic Properties for Polychlorinated Thianthrenes by Density Functional Theory

The structural and thermodynamic （PCTAs） in the ideal gas state at 298.15 K and 1.013 properties of 75 polychlorinated thianthrenes ×10^5 Pa have been calculated at the B3LYP/6- 31G＊ level using Gaussian 98 program. Based on the output data of Gaussian, the isodesmic reactions were designed to calculate standard enthalpy of formation （△fH^θ） and standard free energy of formation （△fH^θ） of PCTAs congeners. The relations of these thermodynamic parameters with the number and position of C1 atom substitution （Npcs） were discussed, and it was found that there exists high correlation between thermodynamic parameters （total energy （TE）, zero-point vibrational energy （ZPE）, thermal correction to energy （Eth）, heat capacity at constant volume （Cv^θ）, entropy （S^θ）, enthalpy （H^θ）, free energy （G^θ）, standard enthalpies of formation （△fH^θ） and standard Gibbs energies of formation （△fG^θ）） and Npcs. On the basis of the relative magnitude of their △fG^θ, the order of relative stability of PCTA congeners was theoretically proposed. In addition, the correlations between structural parameters and Npcs were also discussed. The good correlations were found between molecular average polarizability （α）, energy of the highest occupied molecular orbital （EHOMO）, molecular volume （Vm） and Npcs, and all R^2 values are larger than 0.95. Moreover, it was supposed that the isomer groups with higher toxicity should be Tri-CTA and TCTA.

MEDV-13 for QSRR of 62 Polychlorinated Naphthalenes

A molecular electronegativity distance vector based on 13 atomic types (MEDV-13) is used to describe the structures of 62 polychlorinated naphthalene (PCN) congeners and related to the gas chromatographic relative retention indices (RIs) of PCNs. Using multiple linear regression, a 4-variable quantitative structure-retention relationship (QSRR) with the correlation coefficient of estimations (r) being 0.9912 and the root mean square error of estimations (RMSEE) being 31.4 and the correlation coefficient of predictions (q) and the root mean square error of predictions (RMSEP) in the leave-one-out procedure are 0.9898 and 33.76, respectively.

Attenuating effect of daidzein on polychlorinated biphenyls-induced oxidative toxicity in mouse testicular cells

The attenuating effect of daidzein (DAI) on oxidative toxicity induced by Aroclor 1254 (A1254) was investigated in mouse testicular cells. Cells were exposed to A1254 alone or with DAI. The oxidative damage was estimated by measuring malondialdehyde (MDA) formation, superoxide dismutase (SOD) activity and glutathione (GSH) content. Results show that A1254 induced a decrease of germ cell number, an elevation in thiobarbituric acid reactive substances (TBARS) but a decrease in SOD activity and GSH content. However, simultaneous supplementation with DAI decreased TBARS level and increased SOD activity and GSH content. Consequently, dietary DAI may restore the intracellular antioxidant system to attenuate the oxidative toxicity of A1254 in testicular cells.