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Результаты 2321-2330 из 4,042
Effects of 4-methylbenzylidene camphor (4-MBC) on neuronal and muscular development in zebrafish (Danio rerio) embryos Полный текст
2016
Li, Vincent Wai Tsun | Tsui, Mei Po Mirabelle | Chen, Xueping | Hui, Michelle Nga Yu | Jin, Ling | Lam, Raymond H. W. | Yu, Richard Man Kit | Murphy, Margaret B. | Cheng Jinping, | Lam, Paul Kwan Sing | Cheng, Shuk Han
The negative effects of overexposure to ultraviolet (UV) radiation in humans, including sunburn and light-induced cellular injury, are of increasing public concern. 4-Methylbenzylidene camphor (4-MBC), an organic chemical UV filter, is an active ingredient in sunscreen products. To date, little information is available about its neurotoxicity during early vertebrate development. Zebrafish embryos were exposed to various concentrations of 4-MBC in embryo medium for 3 days. In this study, a high concentration of 4-MBC, which is not being expected at the current environmental concentrations in the environment, was used for the purpose of phenotypic screening. Embryos exposed to 15 μM of 4-MBC displayed abnormal axial curvature and exhibited impaired motility. Exposure effects were found to be greatest during the segmentation period, when somite formation and innervation occur. Immunostaining of the muscle and axon markers F59, znp1, and zn5 revealed that 4-MBC exposure leads to a disorganized pattern of slow muscle fibers and axon pathfinding errors during the innervation of both primary and secondary motor neurons. Our results also showed reduction in AChE activity upon 4-MBC exposure both in vivo in the embryos (15 μM) and in vitro in mammalian Neuro-2A cells (0.1 μM), providing a possible mechanism for 4-MBC-induced muscular and neuronal defects. Taken together, our results have shown that 4-MBC is a teratogen and influences muscular and neuronal development, which may result in developmental defects.
Показать больше [+] Меньше [-]A trench study to assess transfer of pesticides in subsurface lateral flow for a soil with contrasting texture on a sloping vineyard in Beaujolais Полный текст
2016
Peyrard, X. | Liger, L. | Guillemain, C. | Gouy, V.
A trench study to assess transfer of pesticides in subsurface lateral flow for a soil with contrasting texture on a sloping vineyard in Beaujolais Полный текст
2016
Peyrard, X. | Liger, L. | Guillemain, C. | Gouy, V.
Subsurface lateral flow in both texture-contrast soils and catchments with shallow bedrock is suspected to be a non-point source of contamination of watercourses by pesticides used in agriculture. As a case study, the north of the Beaujolais region (eastern France) provides a favorable environment for such contamination due to its agro-pedo-climatic conditions. Environments seen in the Beaujolais region include intense viticulture, permeable and shallow soils, steep hillslopes, and storms that occur during the periods of pesticide application. Watercourse contamination by pesticides has been widely observed in this region, and offsite pesticide transport by subsurface lateral flow is suspected to be involved in diffuse and chronic presence of pesticides in surface water. In order to confirm and quantify the potential role of such processes in pesticide transfer, an automated trench system has been designed. The trench was set up on a steep farmed hillslope in a texture-contrast soil. It was equipped with a tipping bucket flow meter and an automatic sampler to monitor pesticide concentrations in lateral flow at fine resolution, by means of a flow-dependent sampling strategy. Four pesticides currently used in vine growing were studied to provide a range of mobility properties: one insecticide (chlorpyrifos-methyl) and three fungicides (spiroxamine, tebuconazole, and dimethomorph). With this system, it was possible to study pesticide concentration dynamics in the subsurface lateral flow, generated by substantial rainfall events following pesticide applications. The experimental design ascertained to be a suitable method in which to monitor subsurface lateral flow and related transfer of pesticides.
Показать больше [+] Меньше [-]A trench study to assess transfer of pesticides in subsurface lateral flow for a soil with contrasting texture on a sloping vineyard in Beaujolais | Utilisation d'une tranchée pour l'évaluation des transferts latéraux de pesticides en subsurface dans un sol à rupture texturale de perméabilité, dans le Beaujolais de coteaux Полный текст
2016
Peyrard, X. | Liger, L. | Guillemain, C. | Gouy, V. | Milieux aquatiques, écologie et pollutions (UR MALY) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU | International audience | Subsurface lateral flow in both texture-contrast soils and catchments with shallow bedrock is suspected to be a non-point source of contamination of watercourses by pesticides used in agriculture. As a case study, the north of the Beaujolais region (eastern France) provides a favorable environment for such contamination due to its agro-pedoclimatic conditions. Environments seen in the Beaujolais region include intense viticulture, permeable and shallow soils, steep hillslopes, and storms that occur during the periods of pesticide application. Watercourse contamination by pesticides has been widely observed in this region, and offsite pesticide transport by subsurface lateral flow is suspected to be involved in diffuse and chronic presence of pesticides in surface water. In order to confirm and quantify the potential role of such processes in pesticide transfer, an automated trench system has been designed. The trench was set up on a steep farmed hillslope in a texture-contrast soil. It was equipped with a tipping bucket flow meter and an automatic sampler to monitor pesticide concentrations in lateral flow at fine resolution, by means of a flow-dependent sampling strategy. Four pesticides currently used in vine growing were studied to provide a range of mobility properties: one insecticide (chlorpyrifos-methyl) and three fungicides (spiroxamine, tebuconazole, and dimethomorph). With this system, it was possible to study pesticide concentration dynamics in the subsurface lateral flow, generated by substantial rainfall events following pesticide applications. The experimental design ascertained to be a suitable method in which to monitor subsurface lateral flow and related transfer of pesticides.
Показать больше [+] Меньше [-]Bioenergetic trade-offs in the sea cucumber Apostichopus japonicus (Echinodermata: Holothuroidea) in response to CO2-driven ocean acidification Полный текст
2016
Yuan, Xiutang | Shao, Senlin | Yang, Xiaolong | Yang, Dazuo | Xu, Qinzeng | Zong, Humin | Liu, Shilin
Bioenergetic trade-offs in the sea cucumber Apostichopus japonicus (Echinodermata: Holothuroidea) in response to CO2-driven ocean acidification Полный текст
2016
Yuan, Xiutang | Shao, Senlin | Yang, Xiaolong | Yang, Dazuo | Xu, Qinzeng | Zong, Humin | Liu, Shilin
Ocean acidification (OA) caused by excessive CO₂ is a potential ecological threat to marine organisms. The impacts of OA on echinoderms are well-documented, but there has been a strong bias towards sea urchins, and limited information is available on sea cucumbers. This work examined the effect of medium-term (60 days) exposure to three pH levels (pH 8.06, 7.72, and 7.41, covering present and future pH variability) on the bioenergetic responses of the sea cucumber, Apostichopus japonicus, an ecologically and economically important holothurian in Asian coasts. Results showed that the measured specific growth rate linearly decreased with decreased pH, leading to a 0.42 %·day⁻¹ decrease at pH 7.41 compared with that at pH 8.06. The impacts of pH on physiological energetics were variable: measured energy consumption and defecation rates linearly decreased with decreased pH, whereas maintenance energy in calculated respiration and excretion were not significantly affected. No shift in energy allocation pattern was observed in A. japonicus upon exposure to pH 7.72 compared with pH 8.06. However, a significant shift in energy budget occurred upon exposure to pH 7.41, leading to decreased energy intake and increased percentage of energy that was lost in feces, thereby resulting in a significantly lowered allocation into somatic growth. These findings indicate that adult A. japonicus is resilient to the OA scenario at the end of the twenty-first century, but further acidification may negatively influence the grazing capability and growth, thereby influencing its ecological functioning as an “ecosystem engineer” and potentially harming its culture output.
Показать больше [+] Меньше [-]Bioenergetic trade-offs in the sea cucumber Apostichopus japonicus (Echinodermata: Holothuroidea) in response to CO2-driven ocean acidification Полный текст
2016
Yuan, Xiutang | Shao, Senlin | Yang, Xiaolong | Yang, Dazuo | Xu, Qinzeng | Zong, Humin | Liu, Shilin
Ocean acidification (OA) caused by excessive CO2 is a potential ecological threat to marine organisms. The impacts of OA on echinoderms are well-documented, but there has been a strong bias towards sea urchins, and limited information is available on sea cucumbers. This work examined the effect of medium-term (60 days) exposure to three pH levels (pH 8.06, 7.72, and 7.41, covering present and future pH variability) on the bioenergetic responses of the sea cucumber, Apostichopus japonicus, an ecologically and economically important holothurian in Asian coasts. Results showed that the measured specific growth rate linearly decreased with decreased pH, leading to a 0.42 %/day decrease at pH 7.41 compared with that at pH 8.06. The impacts of pH on physiological energetics were variable: measured energy consumption and defecation rates linearly decreased with decreased pH, whereas maintenance energy in calculated respiration and excretion were not significantly affected. No shift in energy allocation pattern was observed in A. japonicus upon exposure to pH 7.72 compared with pH 8.06. However, a significant shift in energy budget occurred upon exposure to pH 7.41, leading to decreased energy intake and increased percentage of energy that was lost in feces, thereby resulting in a significantly lowered allocation into somatic growth. These findings indicate that adult A. japonicus is resilient to the OA scenario at the end of the twenty-first century, but further acidification may negatively influence the grazing capability and growth, thereby influencing its ecological functioning as an "ecosystem engineer" and potentially harming its culture output.
Показать больше [+] Меньше [-]Influence of preozonation on the adsorptivity of humic substances onto activated carbon Полный текст
2016
Rodríguez, Francisco J. | García-Valverde, María
This research aims to study the influence of preozonation on the adsorptivity of humic substances onto activated carbon, which are usual stages in drinking water treatment. Three different types of humic substances were used in this study: natural fulvic and humic acids extracted from the Úzquiza Reservoir (Burgos, Spain) and a commercially supplied humic acid. The fractionation of the humic substances by ultrafiltration showed a very different molecular weight (MW) distribution for them: the lowest fraction of <1 kDa comprises the vast majority of the fulvic acids (around 86 %), whereas the main fraction for the commercial humic acids was the highest one of >30 kDa (around 40 %). The natural humic acids show an intermediate distribution between the two aforementioned humic substances. The 1–5-kDa fraction turned out to be the most reactive toward trihalomethane formation for the commercial humic acids. The adsorptive capacity of activated carbon for the humic substances was in the following order: natural fulvic acids > natural humic acids > commercial humic acids. The most adsorbable fraction was that of <1 kDa for the fulvic acids, whereas the 5–10-kDa fraction was the most adsorbable for both humic acids. Preozonation changes the MW distribution of the humic substances, decreasing the abundance of the high MW fractions and generating smaller molecules within the low to medium MW range. Adsorption isotherms show that preozonation has a beneficial effect on the adsorptivity of the commercial humic acids onto activated carbon, whereas no appreciable effect was observed for the case of the fulvic acids.
Показать больше [+] Меньше [-]Use of mechanistic data in the IARC evaluations of the carcinogenicity of polychlorinated biphenyls and related compounds Полный текст
2016
Lauby-Secretan, Béatrice | Loomis, Dana | Baan, Robert | El Ghissassi, Fatiha | Bouvard, Véronique | Benbrahim-Tallaa, Lamia | Guha, Neela | Grosse, Yann | Straif, Kurt
The IARC Monographs are a series of scientific reviews that identify environmental factors that can increase the risk of cancer in humans. In its first part, the principles and procedures of the IARC Monographs evaluations are summarized. In a second part, we present the most recent IARC evaluation of polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs), performed in February 2013: PCBs and dioxin-like PCBs were both classified into group 1 “carcinogens,” while PBBs were evaluated as “probably carcinogenic to humans” (group 2A). Noteworthy is that the relative contributions of different PCB congeners to the carcinogenicity of PCB mixtures are not known. The use of mechanistic data for the classification into a higher category is discussed in the context of the history of the consecutive evaluations of several related polychlorinated compounds.
Показать больше [+] Меньше [-]Environmental PCBs in Guánica Bay, Puerto Rico: implications for community health Полный текст
2016
Kumar, Naresh | Ramirez-Ortiz, Daisy | Solo-Gabriele, Helena M. | Treaster, Joseph B. | Carrasquillo, Olveen | Toborek, Michal | Deo, Sapna | Klaus, Jim | Bachas, Leonidas G. | Whitall, David | Daunert, Sylvia | Szapocznik, José
Guánica Bay, located in southwestern Puerto Rico, has suffered oil spills and other pollution discharges since the 1960s. Previous research showed elevated concentrations of polychlorinated biphenyls (PCBs) in coral reef and sediment. This research examined PCB concentrations in sediment and fish. Sediment and fish sampling in the bay was facilitated by community members. This study identified the second highest reported PCB level (129,300 ng/g) in sediment in the USA. Fish samples also showed elevated concentrations (1623 to 3768 ng/g), which were higher than the thresholds of safe levels of PCBs in fish for human consumption. The alarmingly high concentration of PCBs calls for proactive community engagement to bring awareness about contamination of the bay and more extensive sampling to test for the concentration of PCBs in seafood and the people of Guánica. This study also underscores the value of the involvement of local communities during sampling design aimed at identifying hot spots of contaminants.
Показать больше [+] Меньше [-]Impact of methionine on a partial-nitritation biofilter Полный текст
2016
Gonzalez-Martinez, Alejandro | Rodriguez-Sanchez, Alejandro | Garcia-Ruiz, Maria Jesus | Osorio, Francisco | Gonzalez-López, Jesús
It has been demonstrated that an anaerobic digestion process cannot attain an efficient removal of several amino acids, with methionine being one of the most persistent of these. Thus, the effect that methionine amino acid has over the partial-nitritation process with fixed-biofilm configuration in terms of performance and bacterial community dynamics has been investigated. With respect to the performance with no addition, 100 mg/L methionine loading decreased ammonium oxidation efficiency in 60 % and 100 % at concentrations of 300 and 500 mg/L methionine, respectively. Bacterial biomass sharply increased by 30, 65, and 230 % with the addition of 100, 300, and 500 mg/L methionine, respectively. Bacterial community analysis showed that methionine addition supported the proliferation of a diversity of heterotrophic genera, such as Lysobacter and Micavibrio, and reduced the relative abundance of ammonium oxidizing genus Nitrosomonas. This research shows that the addition of methionine affects the performance of the partial-nitritation process. In this sense, amino acids can pose a threat for the of partial-nitritation process treating anaerobic digester supernatant at full-scale implementation.
Показать больше [+] Меньше [-]Red cabbage yield, heavy metal content, water use and soil chemical characteristics under wastewater irrigation Полный текст
2016
Tunc, Talip | Sahin, Ustun
The objective of this 2-year field study was to evaluate the effects of drip irrigation with urban wastewaters reclaimed using primary (filtration) and secondary (filtration and aeration) processes on red cabbage growth and fresh yield, heavy metal content, water use and efficiency and soil chemical properties. Filtered wastewater (WW1), filtered and aerated wastewater (WW2), freshwater and filtered wastewater mix (1:1 by volume) (WW3) and freshwater (FW) were investigated as irrigation water treatments. Crop evapotranspiration decreased significantly, while water use efficiency increased under wastewater treatments compared to FW. WW1 treatment had the lowest value (474.2 mm), while FW treatments had the highest value (556.7 mm). The highest water use efficiency was found in the WW1 treatment as 8.41 kg m⁻³, and there was a twofold increase with regard to the FW. Wastewater irrigation increased soil fertility and therefore red cabbage yield. WW2 treatment produced the highest total fresh yield (40.02 Mg ha⁻¹). However, wastewater irrigation increased the heavy metal content in crops and soil. Cd content in red cabbage heads was above the safe limit, and WW1 treatment had the highest value (0.168 mg kg⁻¹). WW3 treatment among wastewater treatments is less risky in terms of soil and crop heavy metal pollution and faecal coliform contamination. Therefore, WW3 wastewater irrigation for red cabbage could be recommended for higher yield and water efficiency with regard to freshwater irrigation.
Показать больше [+] Меньше [-]Assessment of relevant fungal species in clinical solid wastes Полный текст
2016
Noman, Efaq Ali | Al-Gheethi, AA | Norulaini Nik Ab. Rahman, | Nagao, H | Ab. Kadir, MO
The study aimed to determine the fungal diversity in clinical waste samples from a healthcare facility in Penang Malaysia. Different fungi species were detected in 83.75 % of the 92 clinical waste samples that were screened from different sections of the healthcare facility. One hundred fifty fungal isolates comprising of 8 genera and 36 species were obtained. They were purified by using single spore isolation technique. Subsequently, the isolates were identified by phenotypic method based on morphological and culture characteristics on different culture media. Among all fungal isolates, Aspergillus spp. in section Nigri 10.2 %, Aspergillus niger 9.5 %, Aspergillus fumigatus 8.8 %, Penicillium. simplicissium 8 %, Aspergillus tubingensis 7.3 %, Aspergillus terreus var. terreus 6.6 %, Penicillium waksmanii 5.9 % and Curvularia lunata 6.5 % were the most frequent. Among five sections of the Wellness Centre, the clinical wastes collected from the diagnostic labs of haematology section had the highest numbers of fungal species (29 species). Glove wastes had the highest numbers of fungal species (19 species) among 17 types of clinical wastes screened. Among all fungal species, Aspergillus spp. exhibited higher growth at 37 °C than at 28 °C, indicating the potential of these opportunistic fungi to cause diseases in human. These results indicated the potential of hospital wastes as reservoirs for fungal species.
Показать больше [+] Меньше [-]Release of soluble elements from biochars derived from various biomass feedstocks Полный текст
2016
Wu, Hailu | Che, Xiaodong | Ding, Zhuhong | Hu, Xin | Creamer, Anne Elise | Chen, Hao | Gao, Bin
Biochar as soil amendment can increase soil carbon (C) sequestration and mineral nutrients; however, some of its soluble elements may also be unintentionally released during the application. In this work, eight types of biochars were derived from herbaceous, woody, and waste (tailing, manure, sludge) biomass feedstocks through slow pyrolysis at 600 °C in N₂. The elemental composition, specific surface area, morphology, crystalline phases, thermal stability, surface functional groups, and pH of the point of zero charge of the biochars were determined using various methods. These properties varied significantly among the tested biochars, suggesting that feedstock type played an important role in controlling their properties. Laboratory release and toxicity characteristic leaching procedure extraction experiments were conducted to evaluate the potential release of nutritious and toxic element from biochars. Results showed that all the biochars released nutritious elements and thus, may be beneficial to plants when amended in soils. In general, biochars produced from herbaceous and woody biomass feedstocks showed low risks of releasing toxic elements. Biochar derived from sludge, however, might present ecotoxicological challenges for its environmental applications due to the release of toxic elements, such as heavy metals.
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