The proton binding properties of biosorbents

Environmental Chemistry Letters - A broad variety of materials of biological origin have been successfully used in recent decades for the removal of pollutants from waters. These biosorbents...     

Ecotoxicological assessment and evaluation of a pine bark biosorbent treatment of five landfill leachates

When selecting a landfill leachate treatment method the contaminant composition of the leachate should be considered in order to obtain the most cost-effective treatment option. In this study the filter material pine bark was evaluated as a treatment for five landfill leachates originating from different cells of the same landfill in Sweden. The objective of the study was to determine the uptake, or release, of metals and dissolved organic carbon (DOC) during a leaching test using the pine bark filter material with the five different landfill leachates. Furthermore the change of toxicity after treatment was studied using a battery of aquatic bioassays assessing luminescent bacteria (Vibrio fischeri) acute toxicity (30-min Microtox®), immobility of the crustacean Daphnia magna, growth inhibition of the algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor; and genotoxicity with the bacterial Umu-C assay. The results from the toxicity tests and the chemical analysis were analyzed in a Principal Component Analysis and the toxicity of the samples before and after treatment was evaluated in a toxicity classification. The pine bark filter material reduced the concentrations of metal contaminants from the landfill leachates in the study, with some exceptions for Cu and Cd. The Zn uptake of the filter was high for heavily contaminated leachates (≥73%), although some desorption of zinc occurred in less contaminated waters. Some of the leachates may require further treatment due to discharge into a natural recipient in order to reduce the risk of possible biological effects. The difference in pH changes between the different leachates was probably due to variations in buffering capacity, affected by physicochemical properties of the leachate. The greatest desorption of phenol during filtration occurred in leachates with high conductivity or elevated levels of metals or salts. Generally, the toxicity classification of the leachates implies that although filter treatment with pine bark removes metal contaminants from the leachates effectively, it does not alter leachate toxicity noticeably. The leachates with the highest conductivity, pH and metal concentrations are most strongly correlated with an increased toxic response in the score plots of both untreated and treated leachates. This is in line with the toxicity classification of the leachate samples. The results from this study highlight the importance of evaluating treatment efficiency from the perspective of potential recipient effects, rather than in terms of residual concentrations of individual contaminants when treating waters with a complex contamination matrix, such as landfill leachates.     

Anaerobic digestion of chicken feather with swine manure or slaughterhouse sludge for biogas production

Biogas production from anaerobic digestion of chicken feathers with swine manure or slaughterhouse sludge was assessed in two separate experiments. Ground feathers without any pre-treatment were added to 42-L digesters inoculated with swine manure or slaughterhouse sludge, representing 37% and 23% of total solids, respectively and incubated at 25 °C in batch mode. Compared to the control without feather addition, total CH₄ production increased by 130% (P < 0.001) and 110% (P = 0.09) in the swine manure and the slaughterhouse sludge digesters, respectively. Mixed liquor NH₄N concentration increased (P < 0.001) from 4.8 and 3.1 g/L at the beginning of the digestion to 6.9 and 3.5 g/L at the end of digestion in the swine manure and the slaughterhouse sludge digesters, respectively. The fraction of proteolytic microorganisms increased (P < 0.001) during the digestion from 12.5% to 14.5% and 11.3% to 13.0% in the swine manure and the slaughterhouse sludge digesters with feather addition, respectively, but decreased in the controls. These results are reflective of feather digestion. Feather addition did not affect CH₄ yields of the swine manure digesters (P = 0.082) and the slaughterhouse sludge digesters (P = 0.21), indicating that feathers can be digested together with swine manure or slaughterhouse sludge without negatively affecting the digestion of swine manure and slaughterhouse sludge.     

Risk level of chemical cues determines retention of recognition of new predators in Iberian green frog tadpoles

In aquatic environments, many prey rely on chemosensory information from injured (alarm cues) or stressed conspecifics (disturbance cues) to assess predation risk. Alarm cues are considered as a sign of higher risk than disturbance cues. These cues could be used by prey to learn potential new predators. In this study, we tested whether Iberian green frog tadpoles (Pelophylax perezi) exhibited antipredator responses to alarm and disturbance cues of conspecifics and whether tadpoles could associate new predators with alarm or disturbance cues. Tadpoles reduced their activity in the presence of disturbance cues, but only weakly when compared with their response to alarm cues. Also, tadpoles learned to recognize new predators from association with alarm or disturbance cues. However, the period of retention of the learned association was shorter for disturbance than alarm cues. Our results indicate that tadpoles are able to modify their antipredatory behavior according to (1) the degree of risk implied by the experimental cues (2) their previous experience of chemical cues of the predator.     

Pilot study of personal, indoor and outdoor exposure to benzene, formaldehyde and acetaldehyde

There is a lack of data for health risk assessment of long term personal exposure to certain ubiquitous air pollutants present particularly in urban atmospheres. The relationship between ambient background concentrations and personal exposure is often unknown. A pilot campaign to measure indoor concentrations, outdoor concentrations and personal exposure to benzene, formaldehyde and acetaldehyde was conducted in a medium sized French town. A strong contribution to total personal exposure was observed from indoor sources, especially for formaldehyde and acetaldehyde, suggesting that indoor sources are dominant for these compounds. For benzene, the average personal exposure exceeded a 10 μgm^?3 limit value, although this was not the case for the ambient background concentration. For formaldehyde, the limit level was also exceeded. Observations suggest that true personal exposure cannot be determined directly from measurements pertaining from fixed ambient background monitoring stations. It is hoped that this will be taken into consideration by the bodies responsible for monitoring air pollution and the future European Air Quality Directive.     

A roadmap for the conservation of freshwater mussels in Europe

Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other groups remain largely off the public and scientific radar. Freshwater mussels (Bivalvia, Unionida) are an alarming example of this conservation bias and here we point out six conceptual areas that need immediate and long-term attention: knowledge, threats, socioeconomics, conservation, governance and education. The proposed roadmap aims to advance research, policy and education by identifying the most pressing priorities for the short- and long-term conservation of freshwater mussels across Europe.     

Carbon dioxide separation and capture by adsorption: a review

Environmental Chemistry Letters - Rising adverse impact of climate change caused by&nbsp;anthropogenic activities is calling for advanced methods to reduce carbon dioxide emissions. Here, we...     

ARX modeling approach to leak detection and diagnosis

This work presents a time series strategy for detection, location and quantification of leaks in large pipeline systems. The technology has two active components, which operate sequentially: the Detector and the Localizer. The Detector continuously screens real-time data, searching for any anomalies such as leaks, which are detected (or not) depending on their size and position. The Detector is based on auto-regressive multi-input/multi-output (MIMO) ARX predictors with one input filter. Subsequent to successful leak detection, the Localizer is launched to diagnose the leak via estimation of its parameters – diameter and location – using recorded data on a Search Time Window that includes information in the neighborhood of the instant of detection. The Localizer is also an ARX predictor, but with two input processors, the first is a filter for dynamic plant inputs and the second filter processes “parameter signals” of active leaks. The Localizer is developed beforehand via model identification with plant data under the action of known, artificially simulated, leaks. It is, therefore, able to recognize an active pattern of leak parameters, by maximizing the adherence of its predictions to data in the Search Time Window. The proposed detection and location methods were successfully tested in simulated leak scenarios for an industrial naphtha pipeline.     

西安夏季大气亚微米颗粒物化学组成与来源的在线观测研究

西安作为汾渭平原地区最大的城市,大气颗粒物污染形势严峻.2017年夏季期间,在西安市浐灞生态园区运用气溶胶化学组分监测仪,对大气亚微米颗粒物中的非难挥发性组分(NR-PM1)进行了在线监测.观测期间NR-PM1的平均质量浓度为(30.1?±?15.4)μg???m?3.其中有机物含量最高,占NR-PM1总质量浓度的63...     

Do tailings from the Mariana,MG (Brazil), disaster affect the initial development of millet,maize, and sorghum?

Environmental Science and Pollution Research - The collapse of the Fundão dam in Mariana, MG, in 2015 resulted in the overflow of more than 50 million m3 of mud containing mine tailings,...