خيارات البحث
النتائج 871 - 880 من 5,098
Distribution, bioaccumulation and trophic transfer of chlorinated polyfluoroalkyl ether sulfonic acids in the marine food web of Bohai, China
2018
Chen, Hong | Han, Jianbo | Cheng, Jiayi | Sun, Ruijun | Wang, Xiaomeng | Han, Gengchen | Yang, Wenchao | He, Xin
Chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) caused great concerns recently as novel fluorinated alternatives. However, information on their bioconcentration, bioaccumulation and biomagnification in marine ecosystems is limited. In this study, 152 biological samples including invertebrates, fishes, seabirds and mammals collected from Bohai Sea of China were analyzed to investigate the residual level, spatial distribution, bioaccumulation and biomagnification of Cl-PFESAs. 6:2 Cl-PFESA was found in concentrations ranging from <MDL (method detection limit) to 3.84 ng/g ww and it is the dominant congener when compared with concentrations of 8:2 Cl-PFESA. Compared with other bays and regions, levels of 6:2 Cl-PFESA are relatively high in bivalves and fishes from Liaodong Bay. These levels were also found to tend to increase as compared with those in 2010–2014. Logarithm bioaccumulation factors (BAFs) for 6:2 Cl-PFESA ranged from 2.23 to 4.21, implying the bioaccumulation of this compound. The trophic magnification factor (BMF) for 6:2 Cl-PFESA was determined to be 3.37 in the marine food web, indicating biomagnification potential along the marine food chain.
اظهر المزيد [+] اقل [-]Pollution status of marine protected areas worldwide and the consequent toxic effects are unknown
2018
Abessa, Denis M.S. | Albuquerque, Heitor C. | Morais, Lucas G. | Araújo, Giuliana S. | Fonseca, Tainá G. | Cruz, Ana C.F. | Campos, Bruno G. | Camargo, Julia B.D.A. | Gusso-Choueri, Paloma K. | Perina, Fernando C. | Choueri, Rodrigo B. | Buruaem, Lucas M.
Chemical pollution is considered a factor that may threaten marine protected areas (MPAs), and recent studies have found contamination and associated biological effects in some MPAs. However, organized data on this topic are lacking. This study reviewed the literature on pollution in MPAs in order to compile data, determine whether MPAs are influenced by pollution and, whenever possible, describe how they are being affected by contaminants. The results show that the pollution status is unknown in most MPAs worldwide. When any information is available, it is often insufficient to diagnose the threats to biodiversity or to support further actions. More robust and extensive information is available on a small number of MPAs, and much less information is available regarding the negative effects of pollution. More than 80% of the areas studied exhibited evidence of contamination at potentially toxic concentrations or were found to have a status that produced toxic effects on the biota. The scientific community is encouraged to study pollution in MPAs worldwide.
اظهر المزيد [+] اقل [-]In-situ examination of graphene and graphene oxide impact on the depuration of phenanthrene and fluoranthene adsorbed onto spinach (Spinacia oleracea L.) leaf surfaces
2018
Sun, Haifeng | Feng, Ruijie | Nan, Yanli | Chen, Zhang | Sang, Nan
To further assess the human being's exposure to polycyclic aromatic hydrocarbons (PAHs) through the dietary pathway, understanding the partitioning of these chemicals co-existed with nanomaterials in edible vegetable systems deserves specific consideration. In this study, the fiber-optic fluorimetry was applied to in situ examine the effects of graphene (GNS) and graphene oxide (GO) nanosheets on the quantification and depuration of three-ringed phenanthrene (Phe) and four-ringed fluoranthene (Fla) adsorbed individually onto the living spinach (Spinacia oleracea L.) surfaces. When the GNS and GO dosages separately increased to the maximum values: a respective red-shift of 4–5 nm and blue-shift of 2–3 nm occurred for the optimal detection emission wavelengths (λem) of the two PAHs, indicating that individual GNS and GO resulted in different changes to the epicuticular wax (ECW) polarity; GNS-inducing fluorescence quenching for the PAHs was about two times greater than GO, owing to the stronger π-π interactions between PAH molecules and GNS relative to GO; the volatilization coefficients (kC1) were reduced by 31.1% versus 26.7% for Phe, and 51.6% versus 34.4% for Fla, mainly via providing an additional adsorbent and promoting the accessibility of the leaf cuticle; respective photolysis coefficients (kP2) of Phe and Fla decreased by 42.9% and 50.0% with GNS, primarily owing to the enhancement of the ECW light-adsorption capacity, but increased by 33.3% and 40.0% with GO due to its photocatalytic activities; overall, total depuration coefficients (kT1, kT2) of the two PAHs decreased by 11.1–55.6%. These findings demonstrate that GNS and GO significantly alter the depuration behavior of PAHs in vegetable systems, potentially posing a threat to the safety of edible vegetables.
اظهر المزيد [+] اقل [-]Responses of reef building corals to microplastic exposure
2018
Reichert, Jessica | Schellenberg, Johannes | Schubert, Patrick | Wilke, Thomas
Pollution of marine environments with microplastic particles (i.e. plastic fragments <5 mm) has increased rapidly during the last decades. As these particles are mainly of terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened. Recent studies revealed that microplastic ingestion can have adverse effects on marine invertebrates. However, little is known about its effects on small-polyp stony corals that are the main framework builders in coral reefs. The goal of this study is to characterise how different coral species I) respond to microplastic particles and whether the exposure might II) lead to health effects. Therefore, six small-polyp stony coral species belonging to the genera Acropora, Pocillopora, and Porites were exposed to microplastics (polyethylene, size 37–163 μm, concentration ca. 4000 particles L−1) over four weeks, and responses and effects on health were documented.The study showed that the corals responded differentially to microplastics. Cleaning mechanisms (direct interaction, mucus production) but also feeding interactions (i.e. interaction with mesenterial filaments, ingestion, and egestion) were observed. Additionally, passive contact through overgrowth was documented. In five of the six studied species, negative effects on health (i.e. bleaching and tissue necrosis) were reported.We here provide preliminary knowledge about coral-microplastic-interactions. The results call for further investigations of the effects of realistic microplastic concentrations on growth, reproduction, and survival of stony corals. This might lead to a better understanding of resilience capacities in coral reef ecosystems.
اظهر المزيد [+] اقل [-]Source apportionment of aerosol particles at a European air pollution hot spot using particle number size distributions and chemical composition
2018
Leoni, Cecilia | Pokorná, Petra | Hovorka, Jan | Masiol, Mauro | Topinka, Jan | Zhao, Yongjing | Křůmal, Kamil | Cliff, Steven | Mikuška, Pavel | Hopke, Philip K.
Ostrava in the Moravian-Silesian region (Czech Republic) is a European air pollution hot spot for airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and ultrafine particles (UFPs). Air pollution source apportionment is essential for implementation of successful abatement strategies. UFPs or nanoparticles of diameter <100 nm exhibit the highest deposition efficiency in human lungs. To permit apportionment of PM sources at the hot-spot including nanoparticles, Positive Matrix Factorization (PMF) was applied to highly time resolved particle number size distributions (NSD, 14 nm-10 μm) and PM₀.₀₉₋₁.₁₅ chemical composition. Diurnal patterns, meteorological variables, gaseous pollutants, organic markers, and associations between the NSD factors and chemical composition factors were used to identify the pollution sources. The PMF on the NSD reveals two factors in the ultrafine size range: industrial UFPs (28%, number mode diameter - NMD 45 nm), industrial/fresh road traffic nanoparticles (26%, NMD 26 nm); three factors in the accumulation size range: urban background (24%, NMD 93 nm), coal burning (14%, volume mode diameter - VMD 0.5 μm), regional pollution (3%, VMD 0.8 μm) and one factor in the coarse size range: industrial coarse particles/road dust (2%, VMD 5 μm). The PMF analysis of PM₀.₀₉₋₁.₁₅ revealed four factors: SIA/CC/BB (52%), road dust (18%), sinter/steel (16%), iron production (16%). The factors in the ultrafine size range resolved with NSD have a positive correlation with sinter/steel production and iron production factors resolved with chemical composition. Coal combustion factor resolved with NSD has moderate correlation with SIA/CC/BB factor. The organic markers homohopanes correlate with coal combustion and the levoglucosan correlates with urban background. The PMF applications to NSD and chemical composition datasets are complementary. PAHs in PM₁ were found to be associated with coal combustion factor.
اظهر المزيد [+] اقل [-]TERT regulates telomere-related senescence and apoptosis through DNA damage response in male germ cells exposed to BPDE in vitro and to B[a]P in vivo
2018
Ling, Xi | Yang, Wang | Zou, Peng | Zhang, Guowei | Wang, Zhi | Zhang, Xi | Chen, Hongqiang | Peng, Kaige | Han, Fei | Liu, Jinyi | Cao, Jia | Ao, Lin
Increasing evidence shows that impaired telomere function is associated with male infertility, and various environmental factors are believed to play a pivotal role in telomerase deficiency and telomere shortening. Benzo[a]pyrene (B[a]P), a ubiquitous pollutant of polycyclic aromatic hydrocarbons (PAHs), can act as a reproductive toxicant; however, the adverse effect of B[a]P on telomeres in male reproductive cells has never been studied, and the related mechanisms remain unclear. In this study, we explored the effects of benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), the active metabolite of B[a]P, on telomere dysfunction in mouse spermatocyte-derived cells (GC-2) and also the potential role of telomerase in BPDE-induced spermatogenic cell damage. The results showed that BPDE induced cell viability inhibition, senescence, and apoptosis in GC-2 cells in a dose-dependent manner. Shortened telomeres, telomere-associated DNA damage, reduced telomerase activity, and TERT expression were also observed in BPDE-treated cells, accompanied with the activation of DNA damage response pathway (ATM/Chk1/p53/p21). Moreover, by establishing the TERT knockdown and re-expression cell models, we found that TERT regulated telomere length and the expression of DNA damage response-related proteins to influence senescence and apoptosis in GC-2 cells. These in vitro findings were further confirmed in vivo in the testicular cells of rats orally administrated with B[a]P for 7 days. B[a]P treatment resulted in histological lesions, apoptosis, and senescence in the testes of rats, which were accompanied by shortened telomeres, reduced levels of TERT protein, and increased expression of DNA damage response-related proteins. In conclusion, it can be concluded that TERT-mediated telomere dysfunction contributes to B[a]P- and BPDE-induced senescence and apoptosis through DNA damage response in male reproductive cells.
اظهر المزيد [+] اقل [-]Experimental manipulation of dietary arsenic levels in great tit nestlings: Accumulation pattern and effects on growth, survival and plasma biochemistry
2018
Sánchez-Virosta, Pablo | Espín, Silvia | Ruiz, Sandra | Salminen, Juha-Pekka | García-Fernández, Antonio J. | Eeva, Tapio
Arsenic (As) is a ubiquitous metalloid classified as one of the most hazardous substances, but information about its exposure and effects in free-living passerines is lacking. The aim of this study is to elucidate the effect of an As manipulation experiment on survival, growth and physiology of great tits (Parus major). Wild P. major nestlings inhabiting an unpolluted area were dosed with water, 0.2 or 1 μg g⁻¹ d⁻¹ of sodium arsenite (Control, Low and High As groups), whereas those living in a metal-polluted area were dosed with water (Smelter group). Birds accumulated As in tissues (liver, bone and feathers) in a dose-dependent way. Nestlings exposed to 1 μg g⁻¹ d⁻¹ of sodium arsenite showed reduced number of fledglings per successful nest, and those exposed to 0.2 μg g⁻¹ d⁻¹ had reduced wing growth, which could have post-fledging consequences such as increased predation risk. These results suggest that the LOAEL for effects on nestling survival and development in great tits is likely equal to or below 1 μg g⁻¹ d⁻¹. However, limited effects on the biochemical parameters evaluated were found. It has been shown that As may produce oxidative stress and tissue damage, so further research exploring this issue will be carried out in a future study.
اظهر المزيد [+] اقل [-]Concentrations of selected heavy metals in placental tissues and risk for neonatal orofacial clefts
2018
Pi, Xin | Qiao, Yiran | Wei, Yihui | Jin, Lei | Li, Zhiwen | Liu, Jufen | Zhang, Yali | Wang, Linlin | Liu, Yaqiong | Xie, Qing | Ren, Aiguo
Orofacial clefts (OFCs) have multifactorial etiologies. Prenatal exposure to heavy metals can induce OFCs in animal models, but evidence from studies of human subjects is scarce. We examined whether concentrations of mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) in placental tissues are associated with risk for OFCs in offspring. This population-based case-control study included 103 newborns affected by OFCs with available placental tissues and 206 controls randomly selected from 509 non-malformed newborns with available placenta samples, recruited in five rural counties in northern China. Sociodemographic information was collected using a structured questionnaire in face-to-face interviews. The concentrations of Hg, Cd, Pb, and As in placental tissues were analyzed using an inductively coupled plasma-mass spectrometry in helium mode. The median concentrations of Hg (7.4 ng/g), Cd (57.1 ng/g), and Pb (96.1 ng/g) were all statistically significantly higher in OFC cases than in controls (Hg 5.5 ng/g, Cd 38.6 ng/g, and Pb 67.9 ng/g, respectively); no differences were observed between the two groups in median concentrations of As. Concentrations above the median for all subjects were associated with a 2.33-fold (95% confidence interval [CI] 1.33–2.09) increased OFC risk for Cd and a 3.08-fold (95% CI 1.74–5.47) increased risk for Pb. The risk for OFCs increased with concentration tertiles, with an adjusted odds ratio of 3.06 (95% CI 1.36–6.88) for the second tertile and 8.18 (95% CI 6.64–18.37) for the highest tertile of Cd, and 3.88 (95% CI 1.78–8.42) for the second tertile and 5.17 (95% CI 2.37–11.29) for the highest tertile of Pb. The association between Hg concentration and OFC risk was borderline nonsignificant after adjusting for confounding factors. Prenatal exposure to Cd and Pb, as reflected by their concentrations in placental tissues, is associated with an increased risk for neonatal OFCs.
اظهر المزيد [+] اقل [-]European seabass respond more strongly to noise exposure at night and habituate over repeated trials of sound exposure
2018
Neo, Y.Y. | Hubert, J. | Bolle, L.J. | Winter, H.V. | Slabbekoorn, H.
Aquatic animals live in an acoustic world, prone to pollution by globally increasing noise levels. Noisy human activities at sea have become widespread and continue day and night. The potential effects of this anthropogenic noise may be context-dependent and vary with the time of the day, depending on diel cycles in animal physiology and behaviour. Most studies to date have investigated behavioural changes within a single sound exposure session while the effects of, and habituation to, repeated exposures remain largely unknown. Here, we exposed groups of European seabass (Dicentrarchus labrax) in an outdoor pen to a series of eight repeated impulsive sound exposures over the course of two days at variable times of day/night. The baseline behaviour before sound exposure was different between day and night; with slower swimming and looser group cohesion observed at night. In response to sound exposures, groups increased their swimming speed, depth, and cohesion; with a greater effect during the night. Furthermore, groups also showed inter-trial habituation with respect to swimming depth. Our findings suggest that the impact of impulsive anthropogenic noise may be stronger at night than during the day for some fishes. Moreover, our results also suggest that habituation should be taken into account for sound impact assessments and potential mitigating measures.
اظهر المزيد [+] اقل [-]Occurrence, elimination, enantiomeric distribution and intra-day variations of chiral pharmaceuticals in major wastewater treatment plants in Beijing, China
2018
Duan, Lei | Zhang, Yizhe | Wang, Bin | Deng, Shubo | Huang, Jun | Wang, Yujue | Yu, Gang
The occurrence, eliminations, enantiomeric distribution and intra-day variations of five chiral pharmaceuticals (three beta-blockers and two antidepressants) were investigated in eight major WWTPs in Beijing, China. The results revealed that metoprolol (MTP) and venlafaxine (VFX) were of the highest concentrations among the five determined pharmaceuticals with mean concentrations of 803 ng L⁻¹ and 408 ng L⁻¹, respectively in influents, and 354 ng L⁻¹ and 165 ng L⁻¹ in effluents, respectively. Their removal efficiencies, intra-day concentration changes and enantiomeric profiles during wastewater treatment were further analyzed. Loads of these two chiral pharmaceuticals were also studied to reveal drug use pattern. A/A/O+MBR (anaerobic/anoxic/oxic + membrane bio-reactor) followed by joint disinfection treatment process exhibited the high removal efficiencies. No or weak enantioselectivity was observed in most WWTPs. However, obvious enantiomeric fraction (EF) changing of MTP was observed in WWTP3 employing A/A/O+MBR. Intra-day concentration fluctuations of MTP were smaller than VFX. A quick response to sudden rise influent concentration of MTP was observed in WWTP1 effluent but EF response lagged behind. Similar bihourly EF variations in influents and effluents were also observed in most WWTPs for MTP and VFX in consideration of hydraulic residence time (HRT).
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