Semifield assessment of the runoff potential and environmental risk of the parasiticide drug ivermectin under Mediterranean conditions

Introduction  

The antiparasitic ivermectin is of particular concern to regulatory agencies. Ivermectin can reach the environment through the direct emission of dung from livestock on pasture and via manure application on agricultural lands.     

Enhancing p-cresol extraction from soil

Soil washing is a potential technology for rapid removal of organic hydrocarbons sorbed to soils. In this work, p-cresol desorption with different non-ionic surfactants (Tween 80, Brij 30 and Triton X-100) was compared to cyclodextrine and citrate as solubilizer. A series of batch extraction experiments were conducted at 20 °C using the field soil with different extracting solutions at various concentrations to investigate the removal efficiency and to optimize the concentration of the extractant. The use of the different extracting agents was very selective to p-cresol extraction, minimizing soil organic matter releasing and maintaining the natural pH of the soil. The highest asymptotic values of desorption percentages were obtained for Tween 80 and Brij 30 at 48 h. However, Brij 30 ecotoxicity (EC₅₀ = 0.5 mg L⁻¹) is in the same order of that obtained for p-cresol, being this surfactant clearly ruled out. Liquid to solid ratio of 2.5 mL g⁻¹ presented the best extraction results, while concentrations higher than 1 g L⁻¹ for Tween 80 and Citrate did not produce any significant effect on the desorption efficiency. p-Cresol extraction efficiencies higher than 70% and 60% for Tween 80 and Citrate, respectively.     

Performance evaluation of a biotrickling filter treating a mixture of oxygenated VOCs during intermittent loading

Laboratory scale-studies on the biodegradation of a 1:1:1 weight mixture of three oxygenated volatile organic compounds (VOCs), ethanol, ethyl acetate, and methyl-ethyl ketone (MEK) in a biotrickling filter (BTF) were carried out using two identically sized columns, filled with different polypropylene rings. The performance of the BTFs was examined for a period of 10 months applying several operational strategies. Similar performance was obtained for both supports. Intermittent flow rate of trickling liquid was shown beneficial to improve the removal efficiency (RE). Continuous feeding of VOC resulted in an excessive accumulation of biomass so high pressure drop was developed in less than 20-30 d of operation. Intermittent VOC loading with night and weekend feed cut-off periods passing dry air, but without addition of water, was shown as a successful operational mode to control the thickness of the biofilm. In this case, operation at high inlet loads (ILs) was extended for more than 75 d maintaining high REs and low pressure drops. Outlet emission concentrations lower than 100 mg Cm(-3) were obtained for ILs up to 100 g Cm(-3)h(-1) working at 15s of empty bed residence time. The most easily biodegradable compounds ethanol and ethyl acetate were used primarily than MEK. After a 3-wk-starvation period, the system performance was almost restored since the first d of operation, being the removal of the less biodegradable compound, MEK, partially deteriorated.     

Effect of Decalin Solvent on the Thermal Degradation of HDPE

The thermal cracking of HDPE in presence of different amounts of decalin was studied and compared with the reaction carried out in the absence of solvent. The decalin favours the mass and heat transfer during the reaction. In addition, it modifies the thermal degradation mechanism, which facilitates the formation of specific products. The use of decalin substantially increases the C₅–C₃₂ yield in comparison with the solventless reaction. In all cases, linear hydrocarbons such as n-paraffins, α-olefins and α,ω-dienes were detected. Increasing the decalin/plastic ratio led to enhanced α-olefin and n-paraffins yields, but the increase was more significant in the case of α-olefins, which are valuable compounds useful as raw chemicals. A reaction mechanism was proposed to explain the results obtained in presence of decalin. In these reactions, intramolecular radical transfer, secondary radical β-scission and hydrogen transfer from both decalin to intermediate radicals and from the polymer chain to regenerate the decalin play a significant role in determining the plastic conversion and the relative amounts of each product.     

Exploring adaptation choices for grapevine regions in Spain

Our aim was to explore the adaptation choices to climate change in the grapevine regions of Spain from two points of view. First, what are the main reasons for concern? Second, how large is the adaptation effort in each region? We address the first question by measuring sensitivity to climate change with Huglin, Cold Night and Dryness Indices over the entire territory, providing information on the adaptation type (e.g. varieties, zoning, water allocation). We then estimate probabilistic projections across scenario, zone and sensitivity indices in the 56 Protected Designation of Origin areas to inform on the magnitude of the adaptation effort. Second, we propose an adaptation effort measure that is framed according to the local environmental context. Results suggest that most areas urgently need an adaptation plan due to the deterioration of production and quality indices as a result of climate change. Potential opportunities in many climate regions might be limited by current policy. The production objectives of quality and quantity trade-offs will probably need to be revised by analysing the sustainability of grapevine production.     

Influence of americium-241 on the microbial population and biodegradation of organic waste

The present study investigated the influence of ²⁴¹Am on microbial growth and the degradation of organic waste. Leachate samples collected in a lysimeter were periodically analyzed for bacterial growth, under both aerobic and anaerobic conditions. ²⁴¹Am inhibited bacterial growth, and the degradation of organic matter was delayed in comparison with the control. Minimal inhibitory concentration assays and survival curves revealed that it inhibits the growth of Pseudomonas putida F1. The assay also revealed that ²⁴¹Am is more toxic than ²³⁸U, Zn²⁺ and Cd²⁺. This study further led to the finding of four new radionuclide-tolerant bacterial strains: Flavobacterium spp., Pseudomonas gladioli, Chryseobacterium indologenes and Ochrobactrum anthropi. The survival curves of P. gladioli, C. indologenes revealed that these bacteria are resistant to metal as consortia.     

Loft features reveal the functioning of the young pigeon’s navigational system

It is thought that young homing pigeons are able to use information acquired en route for their initial homeward orientation. However, the cues involved and mechanisms utilised are under discussion. Blocking light-dependent route-specific information during the first leg of an outward journey detour, together with analysis of pigeons that were raised under different loft conditions, allowed us to correctly evaluate the functioning of this mechanism and, more generally, the navigational map of birds. Pigeons from the same stock were raised and kept in two different lofts. The birds in the experimental groups were transported to the release sites via detours, and light-dependent information was denied during the first half of the outward journey (no compass information was available). Control birds were transported by the most direct route and had access to all available information. In general, the results showed that the low-loft birds preferred to use magnetic compass cues, whereas the high-loft birds preferred to use navigational map cues to collect information of the first part of the outward journey. The impairments observed in the homing performances of the experimental groups highlight the reliability of information collected inside the map area. Relevant to an understanding of the route-reversal mechanism was the evidence that this mechanism is able to function in the absence of compass information (birds raised in a wind-exposed loft show a detour effect). In systems where directional information could be provided by multiple sources, processing and extracting accurate course trajectories through a common mechanism may prove more efficient and reliable.     

Sex,age, spleen size,and kidney fat of red deer relative to infection intensities of the lungworm <Emphasis Type="Italic">Elaphostrongylus cervi</Emphasis>

We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode Elaphostrongylus cervi in red deer (Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and spleen size were positively correlated in subadults (2–3 years old) and adults (>3 years old), but not in calves (<1 year old) or yearlings (1–2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial energy drain in this age–sex class, as they compete to hold females during the mating season. Body condition related negatively to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth, and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal ecology.     

New epizooic symbioses between sponges of the genera Plakortis and Xestospongia in cryptic habitats of the Caribbean

Three new cases of sponge symbiosis between species of Plakortis and Xestospongia were found in reef caves and mesophotic reef habitats of the Caribbean. Plakortis sp. 1 from the Bahamas associates exclusively with Xestospongia deweerdtae which was originally described living freely on the deep fore-reef and caves of Jamaica. In addition, we found Plakortis sp. 2 from Puerto Rico which associates with both X. deweerdtae and a different Xestospongia sp. Sponge specimens were identified using cytochrome oxidase subunit 1, 28S rRNA and 18S rRNA gene sequence fragments, spicule analysis, and histological sections with SEM. Unlike previous sponge pairs, Xestospongia spp. not only grew as a thin veneer of tissue over the Plakortis host sponge but through the mesohyl, forming inner channels (0.1–1 cm) that may provide a benefit by facilitating more efficient water transport through the dense Plakortis tissue. Symbioses with both Plakortis spp. were documented from an early recruit stage through adulthood. Spicule measurements conducted on symbiotic versus free-living X. deweerdtae revealed significantly smaller spicule sizes for symbiotic individuals, suggesting a cost in terms of silicon availability, or a benefit in terms of a lower investment in skeleton synthesis for support. This study reveals new specialized symbiotic associations between distantly related sponge genera that likely represent an alternative strategy of adaptation for life in reef caves and mesophotic reefs.     

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...