خيارات البحث
النتائج 401 - 410 من 4,929
Phthalate exposure increases subclinical atherosclerosis in young population
2019
Su, Ta-Chen | Hwang, Jing-Shiang | Torng, Pao-Ling | Wu, Charlene | Lin, Chien-Yu | Sung, Fung-Chang
The link between phthalate exposure and the risk of subclinical atherosclerosis in young population remains unclear. This study investigated the association between phthalate exposure and subclinical atherosclerosis, in terms of carotid intima-media thickness (CIMT), in young population. From a nationwide mass urine screening for renal health, conducted in 1992–2000 among school children 6–18 years of age in Taiwan, we recruited 789 subjects to participate in the cardiovascular health examination in 2006–2008. Among them, 787 received measurements of 7 urinary phthalate metabolites and CIMT. Results showed both mean and maximal values of CIMT at all segments of carotid arteries significantly increased with the urinary mono-2-ethylhexyl phthalate (MEHP), ∑ di-(2-ethylhexyl) phthalate (DEHP), and mono-n-butyl phthalate (MnBP) in a dose-response relationship after adjustment for multiple linear regression models. Multivariate logistic regression analysis showed that higher quartiles of urinary concentrations of MEHP, ∑DEHP, and MnBP were associated with a higher risk of thicker CIMT. Compared to subjects with the lowest quartile (Q1) of urinary MEHP, the adjusted odds ratios (95% confidence interval) for thicker CIMT among subjects with higher urinary MEHP were 2.13 (1.18–3.84) at Q2, 4.02 (2.26–7.15) at Q3 and 7.39 (4.16–13.12) at the highest Q4. In conclusion, urinary phthalate metabolites of MEHP, ∑DEHP, and MnBP are strongly associated with CIMT in adolescents and young adults in Taiwan.
اظهر المزيد [+] اقل [-]Bioturbation effects on metal release from contaminated sediments are metal-dependent
2019
Xie, Minwei | Simpson, Stuart L. | Wang, Wen-Xiong
Metal flux measurements inform the mobility, potential bioavailability and risk of toxicity for metals in contaminated sediments and therefore is an important approach for sediment quality assessment. The binding and release of metals that contribute to the net flux is strongly influenced by the presence and behaviors of benthic organisms. Here we studied the effects of bioturbation on the mobility and efflux of metals from multi-metal contaminated sediments that inhabited by oligochaete worms or both worms and bivalves. Presence of bivalves enhanced the release of Mn, Co, Ni and Zn but not for copper and chromium, which is likely due to the high affinities of copper and chromium for the solid phase. Metals in the overlying water were primarily associated with fractions smaller than 10 kDa, and the fractionation of all metals were not affected by the presence of the bivalve. Metal fluxes attributed to different processes were also distinguished, and the bioturbation induced effluxes were substantially higher than the diffusive effluxes. Temporal variabilities in the total net effluxes of Mn, Co, Ni and Zn were also observed and were attributed to the biological activities of the bivalves. Overall, the present study demonstrated that the response of different metals to the same bioturbation behavior was different, resulting in distinct mobility and fate of the metal contaminants.
اظهر المزيد [+] اقل [-]Congener-specific C10C13 and C14C17 chlorinated paraffins in Chinese agricultural soils: Spatio-vertical distribution, homologue pattern and environmental behavior
2019
Aamir, Muhammad | Yin, Shanshan | Zhou, Yuting | Xu, Chenye | Liu, Kai | Liu, Weiping
A comprehensive spatio-vertical survey of short-chain (SCCPs, C10-13) and medium-chain (MCCPs, C14-17) chlorinated paraffins (CPs) was performed in surface and core soils from Chinese nation-wide agricultural lands in 2016, and a total of 48 congener groups were measured. The shorter carbon chain C10-11 in SCCP and C14-15 in MCCP homologue groups, and the lower chlorinated congeners (Cl5-7) for both CP groups were predominant. The ∑SCCP and ∑MCCP concentrations in surface soils ranged from 39 to 1609 ng/g and 127–1969 ng/g, dry weight (dw), respectively. The spatial distribution trend showed that SCCP congener groups with relatively low octanol-water partition coefficient (KOW) and octanol-air partition coefficient (KOA) are uniformly distributed across surface soils compared to MCCP congener groups. Significant relationships were observed between the spatial variation of SCCP concentrations and the driving factors responsible for dispersion and deposition. The distribution behavior of SCCPs and MCCPs in highland and plain surface soils showed an increasing trend of MCCP concentrations with elevation, indicating the “mountain cold-trapping effect”. Vertical distribution profile revealed similar homologue group composition patterns of SCCP and MCCP congener groups as those of surface soils. Furthermore, the penetration potential ratios (r) of chlorine and carbon atoms of CPs demonstrated that the lower chlorinated (Cl5-7) and the shorter carbon chain (C10-13) congener groups are more prone to vertical movement into deeper soil layers compared to the longer carbon chain (C14-17) and highly chlorinated (Cl8-10) congener groups.
اظهر المزيد [+] اقل [-]Depositional input of hydrocarbons recorded in sedimentary cores from Deception and Penguin Islands (South Shetland Archipelago, Antarctica)
2019
Sutilli, Marina | Ferreira, Paulo A.L. | Figueira, Rubens C.L. | Martins, César C.
Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs), including petroleum biomarkers, were studied in four sediment cores collected around Deception and Penguin Islands, Antarctica. Total PAHs in Deception Island (DCP) samples ranged from 2.0 to 26.8 ng g⁻¹, and in Penguin Island (PGI) varied between 13.2 and 60.3 ng g⁻¹. Multiple sources of PAHs were verified in DCP, with petrogenic-derived compounds being predominant over the last 10 years. In PGI, PAHs related to natural contributions from the erosion of coal deposits were reported. Total AHs in DCP ranged from 4.5 to 19 μg g⁻¹ and in PGI varied between 5.3 and 21.9 μg g⁻¹. In DCP, the n-alkanes distribution pattern showed the presence of petroleum residues in the top sections and both terpanes and hopanes were detected, related to the use of fossil fuels for power generation and in different types of vessels. In PGI, the main source of n-alkanes was marine inputs and only terpanes were detected. The slight increase in hydrocarbon levels observed from 1980 onward in DCP was assumed to be due to the development of tourism in the region and to the scientific station activities. In PGI, anthropogenic-related hydrocarbons were detected in the recent sections and were linked to the development of tourism near the island, scientific activities and the increase in vessel traffic. In general, the concentrations of hydrocarbons found around both islands were comparable to those found in uncontaminated Antarctic regions.
اظهر المزيد [+] اقل [-]Recent findings of halogenated flame retardants (HFR) in the German and Polar environment
2019
Dreyer, Annekatrin | Neugebauer, Frank | Lohmann, Nina | Rüdel, Heinz | Teubner, Diana | Grotti, Marco | Rauert, Caren | Koschorreck, Jan
To get an overview about distribution, levels and temporal trends of polybrominated diphenyl ethers (PBDE) and halogenated flame retardants (HFR) of emerging concern, different types of environmental samples archived in the German Environment Specimen Bank as well as fish filet samples from the Arctic (n = 13) and Antarctica (n = 5) were analysed for 43 substances (24 PBDE, 19 HFR) using a multi-column clean-up and GC-API-MS/MS or GC-MS. Sample types were herring gull egg (n = 3), blue mussel (n = 3) and eelpout filet (n = 3) from the German North- and Baltic Sea, bream filet (n = 7), zebra mussel (n = 6) and suspended particulate matter (SPM, n = 7) from German freshwater ecosystems as well as tree leaves (n = 9)/shoots (n = 10), soil (n = 4), earthworm (n = 4) and deer liver (n = 7) as representatives of German terrestrial ecosystems. PBDE and emerging HFR were present in each investigated matrices from Germany and Polar regions showing their widespread distribution. The presence in Arctic and Antarctic fish samples confirms their long-range transport potential. Average concentrations of total emerging HFR were highest in SPM (26 ng g⁻¹ dry weight (dw)), zebra mussel (10 ng g⁻¹ dw) and herring gull egg (2.6 ng g⁻¹ dw). Lowest levels were measured in fish filet samples from Antarctica (0.02 ng g⁻¹ dw). Average total PBDE concentrations were highest in bream filet (154 ng g⁻¹), herring gull egg (61 ng g⁻¹ dw), SPM (21 ng g⁻¹ dw), and zebra mussel 18 (ng g⁻¹) and lowest in deer liver (0.04 ng g⁻¹ dw). The patterns of non-fauna terrestrial samples (leaves, shoots, soil) as well as SPM were dominated by DBDPE and BDE209. Elevated proportions of DPTE and in most cases the absence of DBDPE characterized all fauna samples with the exception of Polar samples. Overall, emerging HFR appeared to be less bioaccumulative than PBDE. Temporal trends were generally decreasing with few exceptions such as DBDPE.
اظهر المزيد [+] اقل [-]Effects of di-n-butyl phthalate on photosynthetic performance and oxidative damage in different growth stages of wheat in cinnamon soils
2019
Gao, Minling | Guo, Zeyang | Dong, Youming | Song, Zhengguo
Herein, we investigated the effects of di-n-butyl phthalate (DBP) on photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) content, oxidative damage, and biomass accumulation of different tissues in wheat (Triticum aestivum L) planted in cinnamon soils. The photosynthetic or fluorescence parameters (except for the intercellular carbon dioxide concentration), chlorophyll content, RuBisCO content, and biomass of roots, stems, and leaves decreased at the seedling, jointing, and booting stages under the stress of DBP. Compared with the control, the content of superoxide anions and hydrogen peroxide in the roots, stems, and leaves increased with increasing DBP concentrations at the seedling, jointing, and booting stages. The activities of superoxide dismutase (SOD) and catalase (CAT) in the roots, stems, and leaves increased under the 10 and 20 mg kg−1 DBP treatments; however, no significant changes were observed under the 40 mg kg−1 DBP treatment at the seedling stage (except for the SOD activity in roots). The increase in SOD and CAT activities in the roots, stems, and leaves with increasing DBP concentration at the jointing and booting stages suggested that an increase in the activities of these antioxidant enzymes may play an important role in defending against excess reactive oxygen species under DBP stress. The biomass of wheat roots, stems, and leaves decreased with an increase in DBP concentration, which was presumably caused by a decrease in photosynthesis and RuBisCO. The effect of DBP on wheat roots, stems, and leaves decreased with wheat growth.
اظهر المزيد [+] اقل [-]Nanotoxicity of different sizes of graphene (G) and graphene oxide (GO) in vitro and in vivo
2019
Jia, Pan-Pan | Sun, Tai | Junaid, Muhammad | Yang, Li | Ma, Yan-Bo | Cui, Zhi-Song | Wei, Da-Peng | Shi, Hao-Fei | Pei, De-Sheng
Graphene family nanomaterials (GFNs) have attracted significant attention due to their unique characteristics and applications in the fields of biomedicine and nanotechnology. However, previous studies highlighted the in vitro and in vivo toxicity of GFNs with size and oxidation state differences are still elusive. Therefore, we prepared graphene (G) and graphene oxide (GO) of three different sizes (S-small, M-medium, and L-large), and characterized them using multiple surface-sensitive analytical techniques. In vitro assays using HEK 293T cells revealed that the small and large sizes of G and GO significantly reduced the cell viability and increased DNA damage, accompanying with activated reactive oxygen species (ROS) generation and induced various expressions of associated critical genetic markers. Moreover, the bacterial assays highlighted that G and GO caused strong acute toxicity on Tox2 bacteria. Effects of G were higher than GO and showed size dependent effect: L > M > S, while the medium size of GO induced mild genetic toxicity on RecA bacteria. In vivo assays revealed that exposure to G and GO caused the developmental toxicity, induced ROS generation, and activated related pathways (specifically GO) in zebrafish. Taken together, G showed stronger ability to decrease the survival rate and induce the acute toxicity, while GO showed obvious toxicity in terms of DNA damages, ROS generation, and abnormal gene expressions. Our findings highlighted that G and GO differentially induced toxicity based on their varying physical characteristics, especially sizes and oxidation state, and exposure concentrations and sensitivity of the employed in vitro and in vivo models. In short, this study provided deep insights on the negative effects of GFNs exposure.
اظهر المزيد [+] اقل [-]Microplastic ingestion by the farmed sea cucumber Apostichopus japonicus in China
2019
Mohsen, Mohamed | Wang, Qing | Zhang, Libin | Sun, Lina | Lin, Chenggang | Yang, Hongsheng
Microplastic ingestion by the farmed sea cucumber is undocumented. Microplastics were isolated from the sea cucumber Apostichopus japonicus that was collected from eight farms along the Bohai Sea and the Yellow Sea in China. To examine microplastic ingestion, the intestines were isolated, digested and then subjected to the floatation test. The microplastic abundance in the sediment ranged from 20 to 1040 particles kg−1 of dry sediment, while the ingested microplastics ranged from 0 to 30 particles intestine−1. After filtering the coelomic fluid, the extracted microplastics from the coelomic fluid ranged from 0 to 19 particles animal−1. Thus, we speculated that microplastics may transfer to the coelomic fluid of sea cucumber. The ingested microplastics did not correlate with the animal body weight but was site dependent, suggesting that sea cucumber may serve as sentinel for microplastic pollution monitoring in the sediment. The microplastics were identified by Fourier transform infrared micro spectroscopy, and the polymer types were mainly cellophane, polyester, and polyethylene terephthalate. This study revealed that, microplastics widely existed in sea cucumber farms, and that sea cucumbers ingest microplastics as suitable with their mouth open. Moreover, the microplastics might transfer to the coelomic fluid of the sea cucumber. Further investigations are needed to assess the chronic effect of the microplastics on the growth and physiological status of the sea cucumber.
اظهر المزيد [+] اقل [-]A potential source for PM2.5: Analysis of fine particle generation mechanism in Wet Flue Gas Desulfurization System by modeling drying and breakage of slurry droplet
2019
Jiang, Binfan | Xie, Yulei | Xia, Dehong | Liu, Xiangjun
Aerosol particulate matter with dynamic diameter smaller than 2.5 μm (PM₂.₅) is the main cause for haze pollution in China. As a dominant precursor of PM₂.₅, SO₂ emitted from industrial process is now strictly controlled by using limestone/gypsum Wet Flue Gas Desulfurization (WFGD) system in China. However, a phenomenon that fine particle derived from WFGD is recently addressed, and is suggested to be a potential source of primary PM₂.₅. Herein, a first investigation into the particle generation mechanism in WFGD system is conducted with a novel droplet (containing particles) drying and breakage model. The proposed model considers a random and porous crust instead of the previous regular crust assumption, and is verified by comparing the modeling results with measurements. An orthogonal test with four factors and three levels is carried out through modeling calculation, and flue gas temperature (Tg) in the inlet is found to be a governing parameter for PM₂.₅ yields in WFGD. With Tg in range of 120–160 °C, PM₂.₅ yields in desulfurizing tower can reach a maximum value at ∼2 × 10⁸ cm⁻³ under typical WFGD condition. To avoid this situation and reduce the PM₂.₅ generation, Tg is suggested to be lower than 120 °C. Additionally, a new insight of the elimination effect of gas-gas heater (GGH) on “gypsum rain” in WFGD system is provided.
اظهر المزيد [+] اقل [-]Supported-liquid phase extraction in combination with isotope-dilution gas chromatography triple quadrupole tandem mass spectrometry for high-throughput quantitative analysis of polycyclic aromatic hydrocarbon metabolites in urine
2019
Jiang, Jie | Ip, Ho Sai Simon | Zhou, Junqiang | Guan, Yufeng | Zhang, Jianqing | Liu, Guihua | Garrotto, Natalia | Lu, Yifu | DeGuzman, Josephine | She, Jianwen
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants with a number of them being carcinogenic. One of the approaches to assess human exposure to PAHs is to measure their urinary metabolites, monohydroxyl polycyclic aromatic hydrocarbons (OH-PAHs), with a method allowing for high throughput and short turn-around time. We developed a method to quantify nine urinary OH-PAHs by using supported liquid phase extraction (SLE) and isotope dilution gas chromatography tandem mass spectrometry (GC-MS/MS). SLE demonstrated advantages over the traditionally used liquid-liquid extraction techniques. The target analytes with spiked deuterated and ¹³C-labeled internal standards were extracted from urine by SLE after enzymatic cleavage of the glucuronide and sulfate conjugates. The extracted analytes were then derivatized with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and analyzed by GC-MS/MS. Six solvent mixtures were evaluated as the SLE extraction solvent, and pentane:chloroform (7:3, v/v) was selected due to its best overall analytical performance. Method detection limits for the 9 analytes ranged from 2.3 to 13.8 pg/mL. Precision and accuracy were satisfactory. SLE and internal isotope labeled standard combination reduced matrix effect effectively. This new method using SLE sample preparation techniques coupled with GC-MS/MS proves applicable to urinary measurements for PAH exposure studies for general population.
اظهر المزيد [+] اقل [-]