Уточнить поиск
Результаты 451-460 из 4,309
Sensitivity of eastern oyster (Crassostrea virginica) spermatozoa and oocytes to dispersed oil: Cellular responses and impacts on fertilization and embryogenesis Полный текст
2017
Vignier, J. | Volety, A.K. | Rolton, A. | Le Goïc, N. | Chu, F.-L.E. | Robert, R. | Soudant, P.
Sensitivity of eastern oyster (Crassostrea virginica) spermatozoa and oocytes to dispersed oil: Cellular responses and impacts on fertilization and embryogenesis Полный текст
2017
Vignier, J. | Volety, A.K. | Rolton, A. | Le Goïc, N. | Chu, F.-L.E. | Robert, R. | Soudant, P.
The 2010 Deepwater Horizon (DWH) oil spill released millions of barrels of oil and dispersant into the Gulf of Mexico. The timing of the spill coincided with the spawning season of Crassostrea virginica. Consequently, gametes released in the water were likely exposed to oil and dispersant. This study aimed to (i) evaluate the cellular effects of acute exposure of spermatozoa and oocytes to surface slick oil, dispersed mechanically (HEWAF) and chemically (CEWAF), using flow-cytometric (FCM) analyses, and (ii) determine whether the observed cellular effects relate to impairments of fertilization and embryogenesis of gametes exposed to the same concentrations of CEWAF and HEWAF. Following a 30-min exposure, the number of spermatozoa and their viability were reduced due to a physical action of oil droplets (HEWAF) and a toxic action of CEWAF respectively. Additionally, reactive oxygen species (ROS) production in exposed oocytes tended to increase with increasing oil concentrations suggesting that exposure to dispersed oil resulted in an oxidative stress. The decrease in fertilization success (1-h), larval survival (24-h) and increase in abnormalities (6-h and 24-h) may be partly related to altered cellular characteristics. FCM assays are a good predictor of sublethal effects especially on fertilization success. These data suggest that oil/dispersant are cytotoxic to gametes, which may affect negatively the reproduction success and early development of oysters.
Показать больше [+] Меньше [-]Sensitivity of eastern oyster ( Crassostrea virginica) spermatozoa and oocytes to dispersed oil: Cellular responses and impacts on fertilization and embryogenesis Полный текст
2017
Vignier, J. | Volety, A. K. | Rolton, A. | Le Goic, N. | Chu, F. -l. E. | Robert, Rene | Soudant, P.
The 2010 Deepwater Horizon (DWH) oil spill released millions of barrels of oil and dispersant into the Gulf of Mexico. The timing of the spill coincided with the spawning season of Crassostrea virginica. Consequently, gametes released in the water were likely exposed to oil and dispersant. This study aimed to (i) evaluate the cellular effects of acute exposure of spermatozoa and oocytes to surface slick oil, dispersed mechanically (HEWAF) and chemically (CEWAF), using flow-cytometric (FCM) analyses, and (ii) determine whether the observed cellular effects relate to impairments of fertilization and embryogenesis of gametes exposed to the same concentrations of CEWAF and HEWAF. Following a 30-min exposure, the number of spermatozoa and their viability were reduced due to a physical action of oil droplets (HEWAF) and a toxic action of CEWAF respectively. Additionally, reactive oxygen species (ROS) production in exposed oocytes tended to increase with increasing oil concentrations suggesting that exposure to dispersed oil resulted in an oxidative stress. The decrease in fertilization success (1-h), larval survival (24-h) and increase in abnormalities (6-h and 24-h) may be partly related to altered cellular characteristics. FCM assays are a good predictor of sublethal effects especially on fertilization success. These data suggest that oil/dispersant are cytotoxic to gametes, which may affect negatively the reproduction success and early development of oysters.
Показать больше [+] Меньше [-]The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons Полный текст
2017
Hang, Jian | Luo, Zhiwen | Wang, Xuemei | He, Lejian | Wang, Baomin | Zhu, Wei
The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons Полный текст
2017
Hang, Jian | Luo, Zhiwen | Wang, Xuemei | He, Lejian | Wang, Baomin | Zhu, Wei
Environmental concerns have been raised on the adverse health effects of vehicle emissions in micro-scale traffic-crowded street canyons, especially for pedestrians and residents living in near-road buildings. Viaduct design is sometimes used to improve transportation efficiency but possibly affects urban airflow and the resultant exposure risk, which have been rarely investigated so far. The personal intake fraction (P_IF) is defined as the average fraction of total emissions that is inhaled by each person of a population (1 ppm = 1 × 10⁻⁶), and the daily carbon monoxide (CO) pollutant exposure (Et) is estimated by multiplying the average concentration of a specific micro-environment within one day. As a novelty, by considering time activity patterns and breathing rates in various micro-environments for three age groups, this paper introduces IF and Et into computational fluid dynamic (CFD) simulation to quantify the impacts of street layouts (street width/building height W/H = 1, 1.5, 2), source location, viaduct settings and noise barriers on the source-exposure correlation when realistic CO sources are defined. Narrower streets experience larger P_IF (1.51–5.21 ppm) and CO exposure, and leeward-side buildings always attain higher vehicular pollutant exposure than windward-side. Cases with a viaduct experience smaller P_IF (3.25–1.46 ppm) than cases without a viaduct (P_IF = 5.21–2.23 ppm) if the single ground-level CO source is elevated onto the viaduct. With two CO sources (both ground-level and viaduct-level), daily CO exposure rises 2.80–3.33 times but P_IF only change slightly. Noise barriers above a viaduct raise concentration between barriers, but slightly reduce vehicular exposure in near-road buildings. Because people spend most of their time indoors, vehicular pollutant exposure within near-road buildings can be 6–9 times that at pedestrian level. Although further studies are still required to provide practical guidelines, this paper provides effective methodologies to quantify the impacts of street/viaduct configurations on human exposure for urban design purpose.
Показать больше [+] Меньше [-]The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons Полный текст
2017
Hang, Jian | Luo, Zhiwen | Wang, Xuemei | He, Lejian | Wang, Baoming | Zhu, Wei
Environmental concerns have been raised on the adverse health effects of vehicle emissions in micro-scale traffic-crowded street canyons, especially for pedestrians and residents living in near-road buildings. Viaduct design is sometimes used to improve transportation efficiency but possibly affects urban airflow and the resultant exposure risk, which have been rarely investigated so far. The personal intake fraction (P_IF) is defined as the average fraction of total emissions that is inhaled by each person of a population (1ppm=1×10-6), and the daily carbon monoxide (CO ) pollutant exposure (Et) is estimated by multiplying the average concentration of a specific micro-environment within one day. As a novelty, by considering time activity patterns and breathing rates in various micro-environments for three age groups, this paper introduces IF and Et into computational fluid dynamic (CFD) simulation to quantify the impacts of street layouts (street width/ building height W/H=1, 1.5, 2), source location, viaduct settings and noise barriers on the source-exposure correlation when realistic CO sources are defined. Narrower streets experience larger P_IF (1.51-5.21 ppm) and CO exposure, and leeward-side buildings always attain higher vehicular pollutant exposure than windward-side. Cases with a viaduct experience smaller P_IF (3.25-1.46 ppm) than cases without a viaduct (P_IF=5.21-2.23 ppm) if the single ground-level CO source is elevated onto the viaduct. With two CO sources (both ground-level and viaduct-level), daily CO exposure rises 2.80-3.33 times but P_IF only change slightly. Noise barriers above a viaduct raise concentration between barriers, but slightly reduce vehicular exposure in near-road buildings. Because people spend most of their time indoors, vehicular pollutant exposure within near-road buildings can be 6-9 times that at pedestrian level. Although further studies are still required to provide practical guidelines, this paper provides effective methodologies to quantify the impacts of street/viaduct configurations on human exposure for urban design purpose.
Показать больше [+] Меньше [-]Acute water quality criteria for polycyclic aromatic hydrocarbons, pesticides, plastic additives, and 4-Nonylphenol in seawater Полный текст
2017
Durán, I. | Beiras, R.
Probabilistic environmental quality criteria for Naphthalene (Nap), Phenanthrene (Phe), Fluoranthene (Flu), Pyrene (Pyr), Triclosan (TCS), Tributyltin (TBT), Chlorpyrifos (CPY), Diuron (DUR), γ-Hexaclorocyclohexane (γ-HCH), Bisphenol A (BPA) and 4-Nonylphenol (4-NP) were derived from acute toxicity data using saltwater species representative of marine ecosystems, including algae, mollusks, crustaceans, echinoderms and chordates. Preferably, data concerns sublethal endpoints and early life stages from bioassays conducted in our laboratory, but the data set was completed with a broad literature survey. The Water Quality Criteria (WQC) obtained for TBT (7.1·10⁻³ μg L⁻¹) and CPY (6.6· 10⁻³ μg L⁻¹) were orders of magnitude lower than those obtained for PAHs (ranging from 3.75 to 45.2 μg L⁻¹), BPA (27.7 μg L⁻¹), TCS (8.66 μg L⁻¹) and 4-NP (1.52 μg L⁻¹). Critical values for DUR and HCH were 0.1 and 0.057 μg L⁻¹ respectively. Within this context, non-selective toxicants could be quantitatively defined as those showing a maximum variability in toxicity thresholds (TT) of 3 orders of magnitude across the whole range of marine diversity, and a cumulative distribution of the TT fitting to a single log-logistic curve, while for selective toxicants variability was consistently found to span 5 orders of magnitude and the TT distribution showed a bimodal pattern. For the latter, protective WQC must be derived taking into account the SSD of the sensitive taxa only.
Показать больше [+] Меньше [-]Multiple mechanisms of heavy metal tolerance are differentially expressed in ecotypes of Artemisia fragrans Полный текст
2017
Alirzayeva, Esmira | Neumann, Günter | Horst, Walter | Allahverdiyeva, Yagut | Specht, Andre | Alizade, Valida
Artemisia fragrans is a plant species with ability of growing on heavy metal-polluted soils. Ecotypes of this species naturally growing in polluted areas can accumulate and tolerate different amounts of heavy metals (HM), depending on soil contamination level at their origin. Heavy metal tolerance of various ecotypes collected from contaminated (AP, SP) and non-contaminated (BG) sites was compared by cultivation on a highly HM-contaminated river sediment and a non-contaminated agricultural control soil.Tissue-specific HM distribution was analyzed by laser ablation-inductively-coupled plasma-mass spectroscopy (LA-ICP-MS) and photosynthetic activity by non-invasive monitoring of chlorophyll fluorescence.Plant-mineral analysis did not reveal ecotype-differences in concentrations of Cd, Zn, Cu in shoots of Artemisia plants, suggesting no differential expression of root uptake or root to shoot translocation of HM. There was also no detectable rhizosphere effect on HM concentrations on the contaminated soil. However, despite high soil contaminations, all ecotypes accumulated Zn only in the concentration range of generally reported for normal growth of plants, while Cu and Cd concentrations were close to or even higher than the toxicity level for most plants. As a visible symptom of differences in HM tolerance, only the AP ecotype was able to enter the generative phase to complete its life cycle. Analysis of tissue-specific metal distribution revealed significantly lower concentrations of Cd in the leaf mesophyll of this ecotype, accumulating Cd mainly in the leaf petioles. A similar mesophyll exclusion was detectable also for Cu, although not associated with preferential accumulation in the leaf petioles. However, high mesophyll concentrations of Cd and Cu in the SP and BG ecotypes were associated with disturbances of the photosynthetic activity.The findings demonstrate differential expression of HM exclusion strategies in Artemisia ecotypes and suggest Cd and Cu exclusion from the photosynthetically active tissues as a major tolerance mechanism of the AP ecotype.
Показать больше [+] Меньше [-]Development and application of a quantification method for water soluble organosulfates in atmospheric aerosols Полный текст
2017
Cao, Gang | Zhao, Xiaopei | Hu, Di | Zhu, Rongshu | Ouyang, Feng
In recent years, organosulfates have been found as a significant component of secondary organic aerosols from both smog chamber experiments and field measurements. In this study, an indirect method was developed to estimate organosulfates in aerosol particles as a whole based on their sulfate functional group. A series of experiments were conducted to optimize and validate the method, and it was then applied to quantify organosulfates in the aerosol samples collected at three sampling characteristic sites in Shenzhen, with one close to a power plant (PP), one at a heavy traffic intersection (HTI), and one on the campus of Harbin Institute of Technology Shenzhen graduate school (HITSZ). On average, the mass concentrations of organic sulfur (Sorg) were 1.98, 1.11, 0.25 μgS m−3 in PP, HTI and HITSZ respectively. The lower bounds of mass concentrations of organosuflates (OMs-related) were 6.86, 3.85 and 0.86 μg m−3 and the upper bounds of mass concentrations of organosulfates were 23.05, 12.93 and 2.90 μg m−3 in PP, HTI and HITSZ respectively. This indicates that primary emissions from coal burning and automobile exhaust can promote the secondary formation of organosulfates in the atmosphere. Overall, the mass concentrations observed in this work were higher than those reported by previous studies.
Показать больше [+] Меньше [-]Cumulative risk assessment of phthalates associated with birth outcomes in pregnant Chinese women: A prospective cohort study Полный текст
2017
Gao, Hui | Xu, Yuan-yuan | Huang, Kun | Ge, Xing | Zhang, Yun-wei | Yao, Hui-yuan | Xu, Ye-qing | Yan, Shuang-qin | Jin, Zhong-xiu | Sheng, Jie | Zhu, Peng | Hao, Jia-hu | Tao, Fang-biao
A prospective cohort study of a Chinese population of mother–neonate pairs (n = 3103) was conducted to investigate the relationship between the cumulative hazard index (HI) of combined diethyl phthalate (DEP), dibutyl phthalate (DBP), dibenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) exposure and birth outcomes. The estimated HI for phthalates was based on phthalate metabolite concentrations in urine collected between 5th and 14th gestational weeks. The median HI values according to the European Food Safety Authority tolerable daily intake (HITDI) and U.S. Environmental Protection Agency reference dose (HIRfD) were 0.358 and 0.187, respectively. A total of 16.3% and 1.9% of the women exhibited HITDI and HIRfD exceeding the value of one, respectively. In unadjusted models, the categories (low < P25, median P25–P50, high > P75) of HITDI were associated with decreased birth weight (β = −26.34 g, p = 0.021) and head circumference (β = −0.09 cm, p = 0.029), whereas those for HIRfD were negatively associated with birth weight (β = −31.74 g, p = 0.005), birth length (β = −0.11 cm, p = 0.032), head circumference (β = −0.13 cm, p = 0.003) and chest circumference (β = −0.10 cm, p = 0.021) in all neonates. Adjustment for potential confounders revealed that HIRfD was inversely associated with head circumference (β = −0.10 cm, p = 0.020). Stratification by gender indicated that HIRfD was associated with decreased birth length (β = −0.17 cm, p = 0.041) in infant boys and HITDI was associated with decreased birth weight (β = −33.12 g, p = 0.036) and head circumference (β = −0.13 cm, p = 0.027) in girls. This is the first study on the cumulative risk assessment of phthalate exposures in pregnant Chinese women. We found that the HI values of multiple phthalate co-exposure were sex-specifically related to birth outcomes.
Показать больше [+] Меньше [-]Chlorpyrifos-induced oxidative damage is reduced under warming and predation risk: Explaining antagonistic interactions with a pesticide Полный текст
2017
Janssens, Lizanne | Stoks, Robby
Interactions with pollutants and environmental factors are poorly studied for physiological traits. Yet physiological traits are important for explaining and predicting interactions at higher levels of organization. We investigated the single and combined impact of the pesticide chlorpyrifos, predation risk and warming on endpoints related to oxidative stress in the damselfly Enallagma cyathigerum. We thereby integrated information on reactive oxygen species (ROS), antioxidant enzymes and oxidative damage. All three treatments impacted the oxidative stress levels and for most traits the pesticide interacted antagonistically with warming or predation risk. Chlorpyrifos exposure resulted in increased ROS levels, decreased antioxidant defence and increased oxidative damage compared to the control situation. Under warming, the pesticide-induced increase in oxidative stress was less strong and the investment in antioxidant defence higher. Although both the pesticide and predation risk increased oxidative damage, the effects of the pesticide on oxidative damage were less strong in the presence of predator cues (at 20 °C). Despite the weaker pesticide-induced effects under predation risk, the combination of the pesticide and predator cues consistently caused the highest ROS levels, the lowest antioxidant defence and the highest oxidative damage, indicating the importance of cumulative stressor effects for impairing fitness. Our results provide the first evidence for antagonistic interactions of warming and predation risk with a pollutant for physiological traits. We identified two general mechanisms that may generate antagonistic interactions for oxidative stress: cross-tolerance and the maximum cumulative levels of damage.
Показать больше [+] Меньше [-]Mercury risk in poultry in the Wanshan Mercury Mine, China Полный текст
2017
Yin, Runsheng | Zhang, Wei | Sun, Guangyi | Feng, Zhaohui | Hurley, James P. | Yang, Liyuan | Shang, Lihai | Feng, Xinbin
In this study, total mercury (THg) and methylmercury (MeHg) concentrations in muscles (leg and breast), organs (intestine, heart, stomach, liver) and blood were investigated for backyard chickens, ducks and geese of the Wanshan Mercury Mine, China. THg in poultry meat products range from 7.9 to 3917.1 ng/g, most of which exceeded the Chinese national standard limit for THg in meat (50 ng/g). Elevated MeHg concentrations (0.4–62.8 ng/g) were also observed in meat products, suggesting that poultry meat can be an important human MeHg exposure source. Ducks and geese showed higher Hg levels than chickens. For all poultry species, the highest Hg concentrations were observed in liver (THg: 23.2–3917.1 ng/g; MeHg: 7.1–62.8 ng/g) and blood (THg: 12.3–338.0 ng/g; MeHg: 1.4–17.6 ng/g). We estimated the Hg burdens in chickens (THg: 15.3–238.1 μg; MeHg: 2.2–15.6 μg), ducks (THg: 15.3–238.1 μg; MeHg: 3.5–14.7 μg) and geese (THg: 83.8–93.4 μg; MeHg: 15.4–29.7 μg). To not exceed the daily intake limit for THg (34.2 μg/day) and MeHg (6 μg/day), we suggested that the maximum amount (g) for chicken leg, breast, heart, stomach, intestine, liver, and blood should be 1384, 1498, 2315, 1214, 1081, 257, and 717, respectively; the maximum amount (g) for duck leg, breast, heart, stomach, intestine, liver, and blood should be 750, 1041, 986, 858, 752, 134, and 573, respectively; and the maximum amount (g) for goose leg, breast, heart, stomach, intestine, liver, and blood should be 941, 1051, 1040, 1131, 964, 137, and 562, respectively.
Показать больше [+] Меньше [-]Baseline tissue concentrations of metal in aquatic oligochaetes: Field and laboratory approaches Полный текст
2017
Méndez-Fernández, Leire | Martinez-Madrid, Maite | Pardo, Isabel | Rodríguez, Pilar
Metal tissue residue evaluation in benthic macroinvertebrates is an important component of an integrated approach to ecological risk assessment of metals and metalloids in the Nalón River basin (North Spain), where historic mining activities took place. The purpose of this study was to know the baseline tissue concentration of 7 metals (Cd, Cu, Cr, Hg, Ni, Pb, and Zn) and one metalloid (As) in aquatic oligochaetes, sediment burrower organisms, representative of the collector-gatherer functional feeding group in the macroinvertebrate community. Metal concentration was measured in sediment and field aquatic oligochaetes at several reference (minimally disturbed) sites of the Nalón River basin, selected following Water Framework Directive criteria. Metal tissue residues were measured separately in field microdriles and lumbricids and compared with tissue concentrations measured in the aquatic oligochaete Tubifex tubifex exposed to reference sediments from the Nalón and other Cantabrian River basins in 28-d chronic laboratory bioassays. Metal tissue residues in bioassay organisms attained usually higher levels than in field worms, in special for As, Cu, Hg and Zn, although metal levels were within the same order of magnitude. The baseline values for metals were calculated from 90th percentile (P90) values in field aquatic oligochaetes (microdriles and lumbricids). The P90 for Hg, As and Zn could efficiently discriminate Toxic and Non-Toxic sites, while baseline values calculated for the other metals deserve further research due either to the low range of values found in the present study, or to the regulation of the metal body concentration, as in the case of Cu.
Показать больше [+] Меньше [-]The influence of e-waste recycling on the molecular ecological network of soil microbial communities in Pakistan and China Полный текст
2017
Jiang, Longfei | Cheng, Zhineng | Zhang, Dayi | Song, Mengke | Wang, Yujie | Luo, Chunling | Yin, Hua | Li, Jun | Zhang, Gan
Primitive electronic waste (e-waste) recycling releases large amounts of organic pollutants and heavy metals into the environment. As crucial moderators of geochemical cycling processes and pollutant remediation, soil microbes may be affected by these contaminants. We collected soil samples heavily contaminated by e-waste recycling in China and Pakistan, and analyzed the indigenous microbial communities. The results of this work revealed that the microbial community composition and diversity, at both whole and core community levels, were affected significantly by polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and heavy metals (e.g., Cu, Zn, and Pb). The geographical distance showed limited impacts on microbial communities compared with geochemical factors. The constructed ecological network of soil microbial communities illustrated microbial co-occurrence, competition and antagonism across soils, revealing the response of microbes to soil properties and pollutants. Two of the three main modules constructed with core operational taxonomic units (OTUs) were sensitive to nutrition (total organic carbon and total nitrogen) and pollutants. Five key OTUs assigned to Acidobacteria, Proteobacteria, and Nitrospirae in ecological network were identified. This is the first study to report the effects of e-waste pollutants on soil microbial network, providing a deeper understanding of the ecological influence of crude e-waste recycling activities on soil ecological functions.
Показать больше [+] Меньше [-]