[Distribution Characteristics and Risk Assessment of 209 Polychlorinated Biphenyls in Dongting Lake and the Inflow Rivers].

In order to fully understand the pollution of polychlorinated biphenyls (PCBs) in Dongting Lake, 209 PCB congeners were quantitatively detected and analyzed by isotope-dilution high-resolution mass spectrometry in 21 surface water sampling sites of Dongting Lake and the inflow rivers of the lake. The results showed that a total of 50 PCB congeners were detected in the study area. The ρ(ΣPCBs) ranged from 0.077 to 10 ng·L-1, with an average concentration of 2.7 ng·L-1 and a median concentration of 1.9 ng·L-1. The order of contamination concentrations were as follows:the inflow rivers of the lake > lake region > outlet. Compared with the reports of domestic and foreign studies, PCB pollution in Dongting Lake is at a low level. The main pollutants in the surface water were dichlorobiphenyls and tri- and tetrachlorobiphenyls, with relative abundances of 67%, 14%, and 16%, respectively. PCB11, PCB17, PCB18, PCB20+33, PCB28, PCB47+75, PCB52, and PCB68 were the most widely distributed and detected in more than 80% of samples. Among them, ρ(PCB11) was the highest, with an average concentration of 1.6 ng·L-1, accounting for 59% of ρ(ΣPCBs), from the domestic organic pigment production process of unintentional emissions. Atmospheric transport deposition and historical residue were the main sources of PCBs in water. According to the toxicity equivalent factor method, the ecological toxicity risk of the study area was evaluated, and the results showed that the TEQ in the water was far lower than the relevant standard limit, indicating that the pollution of PCBs in the surface water of Dongting Lake and the inflow rivers would not cause harm to exposed organisms.

Risk assessment of malignancy in solitary pulmonary nodules in lung computed tomography: a multivariable predictive model study.

BACKGROUND: Computed tomography images are easy to misjudge because of their complexity, especially images of solitary pulmonary nodules, of which diagnosis as benign or malignant is extremely important in lung cancer treatment. Therefore, there is an urgent need for a more effective strategy in lung cancer diagnosis. In our study, we aimed to externally validate and revise the Mayo model, and a new model was established. METHODS: A total of 1450 patients from three centers with solitary pulmonary nodules who underwent surgery were included in the study and were divided into training, internal validation, and external validation sets (n = 849, 365, and 236, respectively). External verification and recalibration of the Mayo model and establishment of new logistic regression model were performed on the training set. Overall performance of each model was evaluated using area under receiver operating characteristic curve (AUC). Finally, the model validation was completed on the validation data set. RESULTS: The AUC of the Mayo model on the training set was 0.653 (95% confidence interval [CI]: 0.613-0.694). After re-estimation of the coefficients of all covariates included in the original Mayo model, the revised Mayo model achieved an AUC of 0.671 (95% CI: 0.635-0.706). We then developed a new model that achieved a higher AUC of 0.891 (95% CI: 0.865-0.917). It had an AUC of 0.888 (95% CI: 0.842-0.934) on the internal validation set, which was significantly higher than that of the revised Mayo model (AUC: 0.577, 95% CI: 0.509-0.646) and the Mayo model (AUC: 0.609, 95% CI, 0.544-0.675) (P < 0.001). The AUC of the new model was 0.876 (95% CI: 0.831-0.920) on the external verification set, which was higher than the corresponding value of the Mayo model (AUC: 0.705, 95% CI: 0.639-0.772) and revised Mayo model (AUC: 0.706, 95% CI: 0.640-0.772) (P < 0.001). Then the prediction model was presented as a nomogram, which is easier to generalize. CONCLUSIONS: After external verification and recalibration of the Mayo model, the results show that they are not suitable for the prediction of malignant pulmonary nodules in the Chinese population. Therefore, a new model was established by a backward stepwise process. The new model was constructed to rapidly discriminate benign from malignant pulmonary nodules, which could achieve accurate diagnosis of potential patients with lung cancer.

[Distribution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Water of Yuqiao Reservoir Watershed During the Water Delivery Period].

In order to understand the pollution status of polycyclic aromatic hydrocarbons (PAHs) in the groundwater of Yuqiao Reservoir Watershed, the 16 US EPA priority control PAHs in the groundwater of this region were analyzed by gas chromatography-mass spectrometry. Not only the distribution characteristics and sources of PAHs, but also the potential probabilistic carcinogenic risk through drinking water and the ecological risk were assessed in this study. The results showed that PAHs could be detected in all the 18 samples. The results showed that the contents and concentration of PAHs were different between the upstream river and Yuqiao Reservoir. For the upstream river, the concentrations of ∑PAHs ranged from 13.7 ng·L-1 to 104.1 ng·L-1, and the low-ring number PAHs was dominant except the site of Sahe river bridge, and 2-3 ring number PAHs accounted for about 86%-95% of the ∑PAHs. The heavier contaminant level was monitored among the intensive fishery breeding areas located in Dahei river reservoir. For the Yuqiao Reservoir, the mass of 2-3 ring and 4-6 ring number PAHs was similar and the concentration of ∑PAHs ranged from 1.6 ng·L-1 to 3512.5 ng·L-1. The highest ∑PAHs was measured at the sampling sites located in the north of reservoir. The resource pollution of PAHs in this region was appointed by the molecular ratio of Flu/Pyr and Fla/(Fla+Pyr) and it showed that the combustion of coal and biomass was predominant during the sampling campaign. The health risk of drinking water in the study area was evaluated using the recommended method by US EPA and the cancer risk exceeded 10-6. The ecological risk was assessed by the value of risk quotient (RQ) adopted by Kalf and the RQs of B[a]A, B[k]F and BaP were all higher than 1. The above results indicated that the government should pay enough attention to the health risk and ecological risk of PAHs in the water of reservoir.

[Distribution Characteristics and Pollution Status of Phthalate Esters in the Groundwater of Hutuo River Pluvial Fan].

A total of 51 groundwater samples were collected from Hutuo River Pluvial Fan in September, 2014, and 6 phthalate esters (PAEs) were analyzed by gas chromatography-mass spectrometry. The distribution characteristics and health risk assessment were investigated in the present study. The results showed that the PAEs could not be detected in only one sample site. The concentration of the six total PAEs ranged between not detectable and 28873.1 ng·L-1, and the PAEs pollution level of the this research area was higher than other regions reported in China. There was obvious difference in the characteristics of space distribution of PAEs constitutes among the three groundwater units. The concentration of PAEs was sequenced from large to small as follows: Gangnan reservoir valley fracture pore water unit (G1)> the pore water unit of the top of Hutuo River Pluvial fan (G2)> the shallow pore water unit of the middle part of Hutuo River Pluvial fan (G3). The results showed that the DMP was dominant in 23 sample sites among all the 39 samples within the G2 and G3 groundwater units, while the concentration of PAEs was relatively higher in the other sample points and the DEHP, DBP were the predominant components, which should be attributed to the industrial point pollution or the pollution originated from surface runoff around the sample sites. The health risk of drinking groundwater polluted by PAEs in the study area was evaluated by the recommended method by US EPA. The non-cancer risk index and the cancer risk index was lower than 1.1×10-2 and 1.2×10-6, respectively, which was both lower than the risk level recommended by US EPA.

[Study on the ecological risk of wild veined rapa whelk (Rapana venosa) exposured to organotin compounds in Bohai Bay, China].

The present study evaluated the potential ecological risk of organotin compounds (OTs) to wild veined rapa whelk (Rapana Venosa) population in Bohai Bay. The results showed that the imposex rate was 12.5% and 6.48% in Dashentang and Nanpaihe coastal areas, with relative penis size index of 9.61 and 12.45, respectively. The concentrations of butyltin compounds and phenyltin compounds were 39.04 ng x g(-1) dw and 46.48 ng x g(-1) dw in muscle tissues, and 32.09 ng x g(-1) dw and 109.03 ng x g(-1) dw in digest gland, respectively. Based on TBT levels in the muscles of all samples, a risk quotient of 0.024 was derived, indicating certain risk of OTs at current levels to wild veined rapa whelk populations in Bohai Bay.

Imposex effects on the veined rapa whelk (Rapana venosa) in Bohai Bay, China.

Environmentally relevant concentrations of organotin compounds (OTs) may trigger sex changes in marine invertebrates and pose a threat to the marine ecosystem. In this study, we investigated organotin levels and the biological responses of wild veined rapa whelk (Rapana venosa) from Lüjuhe district (LJH), Dashentang district (DST), and Nanpaihe district (NPH) in Bohai Bay, China. We found that 11.11 and 22.95 % of the veined rapa whelks from DST and NPH exhibited imposex characteristics with a relative penis size index (RPSI) of 12.50 and 12.31, respectively. The RNA/DNA ratio was significantly lower in females from DST than those from LJH (p < 0.05), and a slight increase in DNA damage was observed in females and imposex individuals compared to males. Moreover, less genetic distance occurred between LJH and NPH (0.016) than between LJH and DST (0.028), although they belonged to the same regional population. OTs analysis showed that triphenyltin chloride concentrations (41.45 ng/g dried weight) were significantly higher than tributyltin concentrations (9.51 ng/g dried weight) in tissues (p < 0.05), but no significant differences were observed in sediments (p > 0.05). In conclusion, the occurrence of imposex individuals and biological responses of the wild veined rapa whelk from Bohai Bay suggest that the marine ecosystem might be at risk.

[Characteristics of heavy metal pollution in Daninghe River and Modaoxi River of Three Gorges Reservoir areas].

In order to explore the potential ecological risk of heavy metals in Three Gorges Reservoir areas, the present study analyzed the heavy metals in sediments and wild crucain carp from Daning River and Modaoxi River which are two typical tributaries, and then the potential risk was evaluated using potential ecological risk index for sediments and comprehensive pollution index for fish, respectively. The results showed that concentrations of Zn and Cr were higher (Daning River: 78.31 and 83.98 mg x kg(-1); Modaoxi River: 99.03 and 94.20 mg x kg(-1)), while Cd was the lowest (Daning River: 0.62 mg x kg(-1); Modaoxi River: 0.75 mg x kg(-1)). Moreover, an obvious increasing trend of these elements was observed in these tributaries from upstream to downstream. For the wild crucain carp, the lowest concentrations of these elements were detected in muscles, and the highest concentrations were in the intestinal. However, no obvious increasing trend of these elements was observed from upstream to downstream. The potential ecological risk in sediments showed a high risk, while no risk was observed in fish.

Construction and characterization of a normalized cDNA library from the river snail Bellamya aeruginosa after exposure to copper.

The construction of a normalized cDNA library is a popular tool for identifying novel biomarkers for monitoring environmental pollution. In the present study, a normalized cDNA library was constructed from the river snail Bellamya aeruginosa after exposure to Cu(2+) by using the SMART technique. The titer of the cDNA library was 1.78 × 10(6) pfu/ml, with a recombinant efficiency of 95.8%. In addition, from 6,000 randomly selected and sequenced clones, 5,473 high-quality ESTs were identified. After processing the sequences, 3,961 unigenes representing 897 contigs and 3,064 singlets were obtained with 27.6% redundancy. Analysis of expressed sequenced tags using COG and GO annotation and KEGG pathway data showed that a large group of genes related to growth and development, signal transduction, and defense mechanisms were present in the cDNA library. Based on our findings, this normalized cDNA library will provide a valuable resource for further research on functional genes and ecotoxicology in B. aeruginosa.

Biomarker responses and genotoxicity in the mud snail (Bullacta exarata) as indicators of coastal contamination.

In the present study different biomarker responses and genotoxicity were determined in wild mud snails (Bullacta exarata) collected from 3 sampling sites in Bohai Bay in northeastern China, which is a region that is under considerable anthropogenic influence. Significant spatial variability of superoxide dismutase (SOD) and metallothionein (MT)-like proteins were recorded, while glutathione transferase (GST), catalase (CAT), and vitellin-like proteins (Vn's) were not observed. Furthermore, genomic DNA that was amplified with 4 fluorescence-labeled primer pairs showed variable genetic distances among the 3 wild mud snail populations found in Bohai Bay, which may be correlated with differences in the types of environmental genotoxicants, such as heavy metals and polycyclic aromatic hydrocarbons. This multi-biomarker approach provided an improved understanding of the potential toxicological impact of contaminated sediments on benthic organisms.

Special distribution of polybrominated diphenyl ethers in brain tissues of free-range domestic hens and ducks from a village near an electronic waste recycling site in South China.

The rural village, Taizhou of Zhejiang Province, had been exposed to e-waste recycling for years, the polybrominated diphenyl ether (PBDE) levels in hens and ducks were high. The concentration of ∑PBDEs in the brain was the lowest among tissues of individual hens and ducks after correction for the respective lipid content. Also, the concentration ratio of BDE-153 versus BDE-154 (153/154) of brain was the highest among tissues of individual hens and ducks. Our results indicate that the hindrance of blood-brain barrier to compounds, such as high molecular weight and non-planar conformation (steric hindrance), contributed to the low concentration of PBDEs in the brain tissue of hens and ducks, especially in cases exposed to high levels of PBDE.

Dual body burdens of polychlorinated biphenyls and polybrominated diphenyl ethers among local residents in an e-waste recycling region in Southeast China.

E-waste recycling resulted in serious pollution of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Taizhou of Zhejiang Province, China. The aims of this study were to assess dual body burdens of the two pollutants and potential health risk for local residents. Blood samples were collected from two e-waste recycling sites, Luqiao (where PCBs-containing e-wastes were recycled) and Wenling (where PBDEs-containing e-wastes were recycled). The mean summation SigmaPCBs (CB-105, 118, 153, 183, and 180) and summation SigmaPBDEs (BDE-28, 47, 99, 100, 153, 154, 180, and 209) were 204.20 and 117.58 ng g(-1) lipid in the blood from Luqiao, respectively, while they were 83.80 and 357.44 ng g(-1) lipid from Wenling, respectively. The PCBs levels among Luqiao residents were comparable to the values reported for US populations, while the PBDEs levels among two study populations were higher than the values from US populations. This is the first report to present dual body burdens of PCBs and PBDEs at so high levels. Based on previous epidemiologic data, it is suggested that dual burdens of PCBs and PBDEs at so high levels might pose health risk for local residents. In addition, no correlation between PCBs or PBDEs concentrations and the ages of the volunteers was observed in the two populations, which was explained by similar exposure time. No correlation of PBDEs with PCBs concentrations suggested different pathways of human exposures to PCBs and PBDEs. Our findings have raised concern about human health risk of dual exposure to PCBs and PBDEs resulting from e-waste recycling.

[Sorption and desorption behaviors of phenanthrene on sediments from the rivers and estuaries flowing into sea around Bohai Bay].

Batch experiments were employed to investigate the sorption and desorption procedures of phenanthrene (Phe) on the river and estuarine sediments. The relationships between sorption parameters and organic matter properties were also discussed. The results indicated that the data on Phe sorption and desorption by different river and estuarine sediments could be fitted well by the linear partitioning and Freundlich model. The linear distribution coefficients (KD) (v) aried from 58 to 743 L x kg(-1). The Freundlich parameters (K(F) and K(FOC)) varied from 75 microg(1-N) x kg(-1) x L(N) to 367 micro(1-N) x kg(-1) x L(N) and from 2253 microg(1-N) x kg(-1) x L(N) to 34743 microg(1-N) x kg(-1) x L(N), respectively. There were significantly positive correlations between K(D) and TOC, TN, DOC, Phe, C/N, DOC/TOC. However, a negative correlation occurred between K(F), K(FOC) values and DOC/TOC ratios. The data on Phe desorption could be better fitted by the Freundlich model than that by linear partitioning model. Except for S1, S8 and S9 samples, the others exhibited obvious sorption and desorption hysteresis. Contents and properties of organic matter were significant as the major factors controlling Phe sorption and desorption to and from the sediments. Considering the frequent impacts of anthropogenic sources on the river and estuarine sediments, the effects of dissolved organic matter on Phe sorption and desorption were perceived to be more important.

[Distribution characteristics of the typical persistent organic pollutants (POPs) in Suaeda heteroptera].

The Suaeda heteroptera are widely distributed in intertidal zone, in order to investigate its function in preventing the transfer of the contaminants from land to sea, the levels and the distribution characteristics of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), decabromodiphenyl ether (BDE209), and polychlorinated biphenyls (PCBs) in Suaeda heteroptera and their associated soils were studied with GC-MS. The results indicated that the levels of these pollutants in Suaeda heteroptera were in the following order: sigma PAHs > OCPs > BDE209 > sigma PCBs (96-1 506 ng/g, 14-577 ng/g, 1.8-33 ng/g, and 399-2 161 pg/g, respectively). The levels of OCPs, PAHs, and PCBs in sediments from Yingkou intertidal zone were higher than that from Donying intertidal zone, however, these pollutants in Suaeda heteroptera leaves were approximately equal, respectively. The distribution of OCPs in Suaeda heteroptera appeared in the following order: stem > root > leaf, and the distribution of PAHs and PCBs in Suaeda heteroptera from Dongying intertidal zone were different from Yingkou intertidal zone, due to the difference of the organic matter content in sediments. The level of BDE209 in sediment from Dongying intertidal zone (19.7 ng/g) was higher than that from Yingkou intertidal zone (2.36 ng/g), and appeared different distribution in Suaeda heteroptera from the two intertidal zones.

Levels and distribution of polybrominated diphenyl ethers in various tissues of foraging hens from an electronic waste recycling area in South China.

Levels and distribution of polybrominated diphenyl ethers (PBDEs) in various tissues of hens foraging near an electronic wastes stack spot in Taizhou, China, were studied. With high-resolution gas chromatography/negative chemical ionization mass spectrometry analysis, 37 PBDE congeners from di- to hepta-brominated and BDE 209 were identified and quantified in the liver, heart, skin, fat, intestine, muscle, blood, oviduct, ovum, gizzard, spleen, and kidney tissues of hens. Based on lipid weight in all analyzed tissues, muscle exhibited the highest PBDE concentrations (17,977 ng/g lipid wt), BDE 209 was the dominant congener, and the sum of quantified PBDEs followed the order muscle > fat > intestine > heart > liver > oviduct > gizzard > blood > skin > ovum. Principal component analysis results indicated that the hen muscle tissue was characterized by BDE 32, 209, 28, and 75 congeners; hen intestine, heart, and blood tissues were characterized by BDE 153, 99, 183, 138, 154, 47, and 100 congeners; and hen skin, liver, oviduct, ovum, gizzard, spleen, kidney, and fat tissues had a similar PBDE congener profile. The present study also indicated that the PBDE congeners were persistent enough to accumulate through the human food chain and that deca-BDE might be potential risk to ecoenvironment.

Feminizing/demasculinizing effects of polychlorinated biphenyls on the secondary sexual development of Xenopus laevis.

We have previously demonstrated that polychlorinated biphenyls (PCBs) have caused phenotypic feminization/demasculinization of gonadal development in Xenopus laevis. Whether PCBs affect secondary sexual development has remained unknown. In this study, X. laevis tadpoles were exposed to Aroclor1254 and PCB(3) from stage 46/47 (system of Nieuwkoop and Faber) for up to 1 month postmetamorphosis. After 24 months postmetamorphosis, the degree of secondary sexual development was examined. Male oviducts were observed in some of the PCB-exposed male frogs, but not in control males. These male oviducts had not completely developed in histological structure when compared with mature female oviducts. Larynx weight and width of PCB-exposed males were significantly less than those of control males. Laryngeal histology showed that PCBs inhibited cartilaginous and muscular development of male frogs, i.e. elastic cartilages had not completely developed and laryngeal muscle fibers were smaller. In a further study on adult male frogs, a decrease in serum testosterone level was found in PCB-exposed frogs compared with controls, but serum estradiol level was not significantly affected. Our study suggests that PCBs can cause phenotypic feminization/demasculinization of male genital ducts and larynges, and these effects may, in part, result from the decrease in serum testosterone level in X. laevis.

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.

Estimation of OCDD degradation rate in soil.

The current concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soils contaminated with Chinese technical product sodium pentachlorophenate (Na-PCP). The estimated half-life of octachlorodioxin (OCDD) was about 14 years in contaminated soils based on the local historical record and mass balance calculation during the past 43 years (1960-2003). The isomer profiles remained the same regardless of paddy field soil or riverbank soil. The results indicated that the congener-specific information was efficient in estimating the PCDD/Fs fate in contaminated soils.