Evolution of biodegradation of deinking by-products used as alternative cover material

Deinking by-products (DBP) have been used as alternative cover material for landfills and mine tailings. Since DBP is biodegradable because of its high cellulose and hemicellulose content, a laboratory experimental program was performed to monitor the evolution of biodegradation and changes in the physico-chemical and geotechnical properties of DBP samples submitted to accelerated biodegradation for 1460 days at 38 degrees C. The evolution of gas and leachate production was monitored in terms of both quality and quantity, which allowed for the calculation of mass loss with time. Under the conditions of the tests (no load applied), 19.6% of the mass was lost as gas, whereas 6.1% was leached out. The results show that biodegradation did not significantly alter the compaction behavior of DBP. The void ratio and water content increased significantly, while the volume of the samples slightly decreased. This seem to indicate that the porous structure of the samples was no longer the same after 1460 d of accelerated biodegradation. A slight increase in the relative density indicates that the organic/inorganic matter ratio increased. The results of permeability tests performed with samples at various stages of biodegradation and at various confining stresses show that the saturated hydraulic conductivity of recompacted biodegraded DBP decreased from 7 x 10(-7)cm/s to approximately 2 x 10(-7)cm/s, as biodegradation advanced.     

PBDEs in serum and blubber of harbor, grey and harp seal pups from Eastern Canada

Serum and blubber of pup harbor (Phoca vitulina), grey (Halichoerus grypus) and harp (Phoca groenlandica) seals from the Estuary and the Gulf of St. Lawrence were analyzed for polybrominated diphenyl ethers (PBDEs). Concentrations of ∑PBDEs (on lipid weight basis) in tissues of harbor seal pups inhabiting the St. Lawrence Estuary were about five times higher than in those from a colony located in the northern Gulf. Harp seal pups have the lowest levels of ∑PBDEs among the seal species born in the Gulf of St. Lawrence. Lipid normalized concentrations of ∑PBDEs in serum and blubber were strongly correlated, suggesting that the blood collection as a less invasive method could be used to monitor ∑PBDEs in pups. This study shows that fluvial inputs of PBDEs are important to the St. Lawrence marine ecosystem and that inhabiting harbor seal pups have a substantial exposure to PBDEs at a critical developmental stage. In addition, the observed difference in PBDE levels between harp and grey or harbor seal pups from the Gulf of St. Lawrence is explained by the difference in diets of their mothers which is linked with their residency time in the Gulf and their seasonal migration pattern.     

Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber

The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4 h whereas its lifetime with respect to the photolysis is higher than 1 d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol.     

Effects of traffic noise on tree frog stress levels,immunity, and color signaling

During the last decade, many studies have focused on the detrimental effects of noise pollution on acoustic communication. Surprisingly, although it is known that noise exposure strongly influences health in humans, studies on wildlife remain scarce. In order to gain insight into the consequences of traffic noise exposure, we experimentally manipulated traffic noise exposure as well as the endocrine status of animals to investigate physiological and phenotypic consequences of noise pollution in an anuran species. We showed that noise exposure increased stress hormone level and induced an immunosuppressive effect. In addition, both traffic noise exposure and stress hormone application negatively impacted H. arborea vocal sac coloration. Moreover, our results suggest profound changes in sexual selection processes because the best quality males with initial attractive vocal sac coloration were the most impacted by noise. Hence, our study suggests that the recent increases in anthropogenic noise worldwide might affect a broader range of animal species than previously thought, because of alteration of visual signals and immunity. Generalizing these results to other taxa is crucial for the conservation of biodiversity in an increasingly noisy world.     

Assessment of nitrogen oxides and ground-level ozone behavior in a dense air quality station network: Case study in the Lesser Antilles Arc

ABSTRACT

This paper presents a study on ground-level ozone (O₃), nitrogen oxides (NO_x = NO + NO₂) concentrations, and their variabilities in the ambient air of three sites of a tropical archipelago that is moderately urbanized. Statistical analysis was performed on a quite complete (>80%) set of 5 years of measurements (2008–2012). There are few studies on those pollutants and their seasonal behavior in the Caribbean area, where pollution level and cities configuration are different from megacities. Analyses are focused on pollutant variations at the scale of the day, the week, and the seasons, using hourly data. The observations show that NO_x concentrations are more elevated during the wet season, whereas O₃ concentrations are higher in the dry season. Amplitudes of ozone cycles are strongly influenced by meteorological conditions (temperature, global radiation, and wind speed) and prevailing levels of NO_x. An ozone weekend effect is detected with the highest amplitude in the city, where anthropogenic activity is the lowest during the weekend. Due to the nature and the origin of pollutants, NO_x shows higher variability than O₃ in the time series. Our results evince the need for continuous measurements of volatile organic compounds (VOCs) in order to better quantify their contribution in O₃ formation in an insular context where numerous natural sources have been identified.

Implications: Statistical analyses of observed NO_x and O₃ concentrations for 5 years for a typical low industrialized site of the Caribbean area have been done. Air quality for those components is correct based on the standards of the World Health Orgaization, pollutant source spatial distributions, and level of industrialization. Observations show the same patterns as in megacities but also a strong impact of weather conditions and road traffic. Behaviors of O₃ cannot be fully explained without VOCs monitoring. Localization and type of AQS should be reconsidered to improve the accuracy of concentrations of the pollutant and better understand their behaviors.     

Periphyton as a bioindicator of mercury pollution in a temperate torrential river ecosystem

Mercury presents a potential risk to the environment and humans, especially in its methylated form. It is among the highest priority environmental pollutants. River Idrijca (Slovenia) is highly contaminated with mercury due to past mercury mining. The aim of this work was to investigate whether the periphyton community in rivers such as Idrijca is a suitable indicator of Hg pollution and of changes in mercury methylation and could serve as an early warning system of increased input of MeHg in the food chain. Periphyton is the only site of primary production in temperate torrential rivers such as Idrijca and is therefore an important link in the food chain. It is also a potential site of Hg accumulation and its introduction to higher trophic levels. Our aim was to assess the response of the periphyton to seasonal and spatial variations in mercury levels and to evaluate its potential as an early warning system of changes in mercury reactivity and mobilization The results indicate that periphyton in a torrential river is too complex and unpredictable to be used as a sole indicator of mercury concentrations and changes in the river. Nevertheless, it can complement environmental measurements due to its importance in the riverine food web.     

Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers

In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas (n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones (n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25–35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.