Adsorptive removal of a synthetic textile dye using cocoa pod husks

The adsorption of a synthetic textile dye (Remazol Brilliant Black Reactive) on cocoa pod husk-based activated carbon was investigated in batch process. The adsorbent prepared was characterized by gas adsorption surface analysis (Brunauer Emmett Teller, BET), scanning electron microscopy, and Fourier transform infrared spectroscopy. The effects of initial dye concentration, contact time, solution temperature, and solution pH were evaluated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models, the first being the best with maximum monolayer coverage of 111?mg?g^?1. Kinetic data were fitted into pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models; the pseudo second-order model provided the best correlation. Maximum adsorption was observed at pH 7. Standard free energy, standard enthalpy, and standard entropy were also calculated. The adsorption interaction was found to be endothermic and spontaneous. Both the mean free energy of adsorption and the activation energy show that the mechanism is by physisorption.     

Induction of micronuclei in bone marrow cells and hepatotoxicity of one of the most common over-the-counter pyrethroid insecticide products in Nigeria

Increasing environmental pollution in the tropics is creating a breeding ground for mosquitoes, leading to increasingly frequent use of insecticides to combat home infestation of mosquitoes, the vector of malarial parasites. Household members are therefore more prone to aerosol exposure and subsequent health effects. We assessed the hepatotoxic and clastogenic effects in rats exposed to different levels of aerosols of one of the insecticides most commonly in used in Nigeria. There were significant (p?2 in the groups of rats exposed to the aerosols when compared with the control group. In addition, rats exposed to the insecticide aerosols have elevated activities of serum enzymes: γ-glutamyl transferase, aspartate amino transferase and alanine amino transferase, as well as number of micronuclei scored in the bone marrow, at levels that are significantly (p?相似文献   

Adsorption of methylene blue onto activated carbon derived from periwinkle shells: kinetics and equilibrium studies

Periwinkle shell, an abundant and inexpensive natural resource, was used to prepare activated carbon by physicochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO₂) as the activating agents at 850 °C for 2 h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 25 °C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 500.00 mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue on activated carbon derived from periwinkle shell could best be described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.     

Risks to the stratospheric ozone shield in the Anthropocene: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Ozone Layer

Crutzen (1974) and Crutzen and Ehhalt (1977) presented two key papers in Ambio that in Ambioexemplify how science first revealed to humankind the potential for damage to our ozone shield in the Anthropocene. Crutzen’s (1974) review is a sweeping summary of the risks to the ozone layer from supersonic aircraft, chlorofluorocarbons, as well as nuclear weapons testing and nuclear war. Crutzen and Ehhalt (1977) described how the nitrous oxide produced from fertilizers could pose another threat to the stability of the stratospheric ozone layer. The two papers are part of a body of influential scientific work that led to the pioneering Montreal Protocol to Protect the Earth’s Ozone Layer to phase out production of chlorofluorocarbons (in 1987), as well as national decisions that slowed or stopped production of supersonic planes (in the 1970s). They remain guideposts today for ongoing international negotiations regarding reducing emissions from fertilizer and limiting nuclear testing.     

A 2.5‐million‐year perspective on coarse‐filter strategies for conserving nature's stage

Climate change will require novel conservation strategies. One such tactic is a coarse‐filter approach that focuses on conserving nature's stage (CNS) rather than the actors (individual species). However, there is a temporal mismatch between the long‐term goals of conservation and the short‐term nature of most ecological studies, which leaves many assumptions untested. Paleoecology provides a valuable perspective on coarse‐filter strategies by marshaling the natural experiments of the past to contextualize extinction risk due to the emerging impacts of climate change and anthropogenic threats. We reviewed examples from the paleoecological record that highlight the strengths, opportunities, and caveats of a CNS approach. We focused on the near‐time geological past of the Quaternary, during which species were subjected to widespread changes in climate and concomitant changes in the physical environment in general. Species experienced a range of individualistic responses to these changes, including community turnover and novel associations, extinction and speciation, range shifts, changes in local richness and evenness, and both equilibrium and disequilibrium responses. Due to the dynamic nature of species responses to Quaternary climate change, a coarse‐filter strategy may be appropriate for many taxa because it can accommodate dynamic processes. However, conservationists should also consider that the persistence of landforms varies across space and time, which could have potential long‐term consequences for geodiversity and thus biodiversity.     

多种聚氧乙烯牛脂胺混合物MON 0818的水生环境危害评估：实验室急性暴露实验基础上的物种敏感度分布

本实验利用标准短期(48- 96 h)实验室测试测定了包括初级生产者，底栖无脊椎动物，水蚤类动物，软体动物和鱼类在内的15种水生生物对于MON 0818的敏感性。MON 0818是一种商业表面活性剂，由多种聚氧乙烯牛脂胺混合而成。此外本实验使用模糊网纹蚤(Ceriodaphnia dubia)潜在的长期(8 d)毒性，确定了暴露浓度。长期毒性测试中未在任何终端指标中发现显著效果。利用得出的数据和文献记载得到物种敏感度在4种暴露条件下的分布，通过对比物种敏感度分布进行了tier-1危害评估。评估显示在本研究规划下(以综述为原型，研究林业除草剂；12 L标准每公顷，等于4.27 kg每公顷) 最差的情况(无意中以最大标签使用速率直接过量喷洒到15 cm深的水体中)会造成中等危害(43.1%的物种处于暴露中，高于中位有效浓度水平)。在更多以最大使用速率使用的典型情况下，受到损害的物种降至20.9%(6 L标准每公顷，相当于2.14 kg每公顷)，在更频繁的雇佣施用速率(2.5 L标准每公顷，相当于0.89 kg每公顷)下，受损物种比例降至6.9%。通过草甘膦在环境中的最大测定浓度计算得到MON 0818的浓度，最终受损物种比例(3.8%)则小于此浓度下受损物种比例(5%)。
精选自Jose L. Rodriguez-Gil, Ryan Prosser, David Poirier, Linda Lissemore, Dean Thompson, Mark Hanson, Keith R. Solomon. Aquatic hazard assessment of MON 0818, a commercial mixture of alkylamine ethoxylates commonly used in glyphosate-containing herbicide formulations. Part 1: Species sensitivity distribution from laboratory acute exposures. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 501–511, July 2017. DOI: 10.1002/etc.3559
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3559/full
     

An in-depth human health risk assessment of potentially toxic elements in highly polluted riverine soils,Příbram (Czech Republic)

Environmental Geochemistry and Health - Environmental pollution by potentially toxic element (PTE) and the associated health risks in humans are increasingly becoming a global challenge. The...     

Impact of economic policy uncertainty,energy intensity,technological innovation and R&D on CO2 emissions: evidence from a panel of 18 developed economies

Environmental Science and Pollution Research - This study examines the impact of economic policy uncertainty (EPU) and ecological innovation on carbon (CO2) emissions in a panel of 18...     

An exposure assessment for selected pharmaceuticals within a watershed in Southern Ontario

Recent studies from a number of countries have shown that measurable concentrations of both human and veterinary pharmaceuticals can be found in a variety of environmental matrices such as surface and ground water, soils, and sediments. Few data are available that characterize the sources, exposure and effects of pharmaceuticals in the environment and there is clearly a need to define these parameters within a Canadian context. We present in this paper the first report in southern Ontario, Canada on the geographic and temporal distribution of pharmaceuticals detected within seven tributaries receiving primarily agricultural inputs in a typical watershed. Of the 28 pharmaceuticals surveyed, 14 were detected in the streams sampled (n=125). Temporal trends in concentration for five frequently detected pharmaceuticals show pulses occurring between May and November of 2003 at similar but varying times over the seasons, depending on the pharmaceuticals, flow rate, and precipitation. Fluctuations in concentration of ions indicative of agricultural run off, such as nitrate and phosphate, were not found to be useful predictors of changes in pharmaceutical concentration (P>0.4), however a significant correlation between dissolved organic carbon and monensin and carbamazepine concentrations were observed (P<0.013). Exposure profiles illustrating concentration distributions for three of the more prevalent pharmaceuticals detected, including lincomycin, monensin and carbamazepine, showed a log normal distribution, useful for calculating centiles of environmental concentrations. While distributions of estimated total potency of pharmaceuticals detected in the surface waters suggested small risks of environmental effects of mixtures to daphnia, green algae, Lemna gibba, and fish, the significance of non-target effects and impacts due to chronic low level exposures to chemical mixtures remains unclear.