The effects of Ag-NPs and AgNO3 on the isopod Porcellionides pruinosus were determined upon soil and dietary exposures. Isopods avoided Ag in soil, with EC50 values of ~16.0 and 14.0 mg Ag/kg for Ag-NPs and AgNO3, respectively. Feeding inhibition tests in soil showed EC50s for effects on consumption ratio of 127 and 56.7 mg Ag/kg, respectively. Although similar EC50s for effects on biomass were observed for nanoparticulate and ionic Ag (114 and 120 mg Ag/kg dry soil, respectively), at higher concentrations greater biomass loss was found for AgNO3. Upon dietary exposure, AgNO3 was more toxic, with EC50 for effects on biomass change being >1500 and 233 mg Ag/kg for Ag-NPs and AgNO3, respectively. The difference in toxicity between Ag-NPs and AgNO3 could not be explained from Ag body concentrations. This suggests that the relation between toxicity and bioavailability of Ag-NPs differs from that of ionic Ag in soils.

Bottom bed waste (BBW) from combustion of forest biomass residues was characterized aiming its use as partial substitute of fresh bed sand (FBS) in industrial bubbling fluidized bed combustors (BFBC). BBW partide size distribution, elemental composition (mainly Si, Ca, Al, Na, K, P and Mg) and mineralogy were evaluated considering also the influence of the characteristics of the biomass used as fuel. Biomass combustion experiments were developed using a pilot-scale bubbling fluidized bed combustor. The operating conditions during the experiments were monitored, namely the flue gas composition (CO2, O-2 and CO), temperature and pressure, and compared with data collected from BFBC located in two industrial biomass thermal power plants. Physical, chemical and mineralogical characteristics of the FBS and BBW revealed that practices related with biomass handling at the forest strongly influence the BBW properties, in terms of not only coarse soil particle addition (>1.0 mm) but also mineralogically. However, the results obtained here indicate that by sieving of BBW it is possible to recover almost 60% of the original BBW particles (size between 0.3 and 1.0 mm), which have properties that allow its reuse as substitute of FBS for bed make-up in industrial BFBC.

Most studies in soil ecotoxicology are designed to assess the effects of individual chemicals on individual test species, using a reference soil (e.g. LUFA 2.2, OECD soil). There is therefore an urgent need for a more comprehensive and integrated approach in order to assess the impact of chemical pollutants on soil ecosystems. In this study, a more realistic scenario in ecotoxicity evaluation was achieved through the use of microcosm-based experiments, using a small-scale terrestrial ecosystem ("STEM") containing Mediterranean agricultural soil. Earthworms (Eisenia andrei) and turnip seeds (Brassica rapa) were introduced into the microcosms, in order to examine the effects of the acaricide spirodiclofen and the insecticide dimethoate, both in single and binary combination exposures. Results showed that for plants and earthworms the recommended application dose of both pesticides did not cause impairment of growth, although increasing concentrations resulted in a biomass decrease for both species. Earthworms were found to alter their depth distribution as a response to the combined application of the two pesticides, with this parameter being more sensitive than body mass. The various binary mixtures tested resulted in antagonistic effects on B. rapa shoot length and fresh weight. Regarding the depth distribution of earthworms, antagonism was observed at field dose, as well as at five times the field dose for both pesticides, while synergism occurred at ten times the field dose. (C) 2011 Elsevier B.V. All rights reserved.

For several years now, forest fires have been known to increase overland flow and soil erosion. However, mitigation of these effects has been little studied, especially outside the USA. This study aimed to quantify the effectiveness of two so-called emergency treatments to reduce post-fire runoff and soil losses at the microplot scale in a eucalyptus plantation in north-central Portugal. The treatments involved the application of chopped eucalyptus bark mulch at a rate of 10–12 Mg ha−1 , and surface application of a dry, granular, anionic polyacrylamide (PAM) at a rate of 50 kg ha−1 . During the first year after a wildfire in 2010, 1419 mm of rainfall produced, on average, 785 mm of overland flow in the untreated plots and 8.4 Mg ha−1 of soil losses. Mulching reduced these two figures significantly, by an average 52 and 93%, respectively. In contrast, the PAM-treated plots did not differ from the control plots, despite slightly lower runoff but higher soil erosion figures. When compared to the control plots, mean key factors for runoff and soil erosion were different in the case of the mulched but not the PAM plots. Notably, the plots on the lower half of the slope registered bigger runoff and erosion figures than those on the upper half of the slope. This could be explained by differences in fire intensity and, ultimately, in pre- fire standing biomass.

Studying tolerance limits in organisms exposed to climatic variations is key to understanding effects on behaviour and physiology. The presence of pollutants may influence these tolerance limits, by altering the toxicity or bioavailability of the chemical. In this work, the plant species Brassica rapa and Triticum aestivum and the earthworm Eisenia andrei were exposed to different levels of soil moisture and carbaryl, as natural and chemical stressors, respectively. Both stress factors were tested individually, as well as in combination. Acute and chronic tests were performed and results were discussed in order to evaluate the responses of organisms to the combination of stressors. When possible, data was fitted to widely employed models for describing chemical mixture responses. Synergistic interactions were observed in earthworms exposed to carbaryl and drought conditions, while antagonistic interactions were more representative for plants, especially in relation to biomass loss under flood-simulation conditions. (C) 2011 Elsevier Ltd. All rights reserved.

Biochar, i.e. pyrolysed biomass, as a soil conditioner is gaining increasing attention in research and industry, with guidelines and certifications being developed for biochar production, storage and handling, as well as for application to soils. Adding water to biochar aims to reduce its susceptibility to become airborne during and after the application to soils, thereby preventing, amongst others, human health issues from inhalation. The Bagnold model has previously been modified to explain the threshold friction velocity of coal particles at different moisture contents, by adding an adhesive effect. However, it is unknown if this model also works for biochar particles. We measured the threshold friction velocities of a range of biochar particles (woody feedstock) under a range of moisture contents by using a wind tunnel, and tested the performance of the modified Bagnold model. Results showed that the threshold friction velocity can be significantly increased by keeping the gravimetric moisture content at or above 15% to promote adhesive effects between the small particles. For the specific biochar of this study, the modified Bagnold model accurately estimated threshold friction velocities of biochar particles up to moisture contents of 10%.

Bottom and fly ashes streams collected along a year in several biomass thermal plants were studied. The bulk composition of ashes and other chemical characteristics that may impact soil application showed a high variability depending on the ash stream, combustion technology and ash management practice at the power plants. The acid neutralization capacity (ANC) and metal’s availability for leaching at fixed pH 7 and 4 was performed according with EA NEN 7371, as a quick evaluation method to provide information on the long-term behavior of ashes, regarding heavy metals and also plant nutrients release. Also the pH dependence leachability study was performed according to CEN/TS 14429 for predicting the leaching behavior under different scenarios. Leachability profiles were established between pH 3 and 12, allowing to distinguish different solubility control phenomena of toxic heavy metals (Cu, Cr, Mn, Ni, Zn, Pb) as well as other salts (Ca, K, Mg, Na, Cl). The ANC of fly ashes at pH 4 (3.6–9.6 molH+/kg) were higher than that observed for the bottom ashes (1.2–2.1 molH+/kg). Ashes were also characterized for persistent organic pollutants (POP), such as polycyclic aromatic hydrocarbons (PAH) and paradibenzodioxines and furanes (PCDD/F). Contents were found to be much higher in fly ash than in bottom ash streams. None of the PAH levels did reach the current national limit value of sewage sludge application in soils or the guide value for ash in north European countries. However, PCDD/F contents, which are not regulated, varied from non-detectable levels to high amounts, regardless the level of loss on ignition (LOI) or unburned carbon content in fly ashes. Given the current ash management practices and possible use of blends of bottom and fly ash streams as soil conditioners resembles clear the urgent need to regulate ash utilization in soils, incorporating limit values both for heavy metals, PAH and PCDD/F.

Mestrado em Poluição Atmosférica | Com o presente trabalho “Inventário de Emissões de Compostos orgânicos Voláteis Biogénicos (COVBs) com apoio em SIG’s”, desenvolveu-se um método de cálculo que nos permite quantificar e prever os valores de emissão de monoterpenos, isopreno e OCOVs, para o coberto vegetal em Portugal Continental. Para a quantificação das emissões de COVs biogénicos foi necessário recorrer a um conjunto de dados (ocupação do solo, temperatura, radiação, coeficiente de biomassa e factores de emissão) cuja resolução espacial/temporal são determinantes nos erros associados à sua estimativa. A partir das cartas de uso de solo, em formato SIG (ano de 1995), dados de temperatura e radiação solar (ano de 2000), factores de emissão assim como coeficientes de biomassa obtidos da bibliografia foram efectuados cálculos, com recurso à Programação em Pascal e Software Excel e Arcview. As emissões de COVs foram calculadas com uma resolução espacial de 100? 100 m2 e resolução temporal horária, sem perder a georeferenciação dos dados de entrada. Por conseguinte é sempre possível aglutinar informação quer em termos espaciais quer temporais, assim como por espécie vegetal e/ou composto (monoterpenos, isopreno e OCOVs). Foram realizados testes de sensibilidade para avaliar os erros de quantificação associados às variáveis temperatura e radiação solar que controlam os fluxos de emissão. Os dados de emissão estimados de monoterpenos, isopreno e OCOVs são apresentados em formato SIG para Portugal Continental, a título de exemplo, para emissões totais (monoterpenos, isopreno e OCOVs) e por espécie (pinheiro bravo, eucalipto, sobreiro e azinheira) para os meses de Janeiro (valores de emissão mínimos) e Agosto (valores de emissão máximos). Em gráficos e tabelas são apresentados os dados de emissão de COVs mensais por espécie e por composto. | With the present essay, “ Inventory of Biogenic Volatile Organic Compounds (COVB’s) Emissions With support on GIS” it has been created a calculation method in order to allow us to quantify and forsee emission values of isoprene and monoterpenes and OVOC’s to the existing vegetation in the continental part of Portugal. For this quantification of biogenc VOC’s emissions it’s necessary to use a whole group of data (soil occupation, temperature, solar radiation, biomass coeficient and emission factors), whose time/space resolution are determinant in relation to errors associated to their calculation. Based on soil use maps in GIS format (year 1995), solar radiation and temperature (2000), emissions factors and biomass coeficients obtained from the recommended list of books, there have been made several calculations using Pascal Programation Language, ArcView and Excel Software. The VOC’s emissions have been calculated with support on a space resolution of 100? 100 m2 and time resolution of an hour, not forgeting the georeferenciation of entry data. In consequence, it’s always possible to gather information not only in terms of time and space but also in terms of vegetal specie and/or compound (monoterpene, isoprene and OVOC’s). There have been made sensitivity tests in order to evaluate the quantification errors associated with temperature’s variations and solar radiation wich control the emissions flows. The estimate monoterpene, isoprene and OVOC’s, emissions data are going to be present for the continental part of Portugal in GIS format, as an example, by total emissions (monoterpenes, isoprene and OVOC’s) and by species (maritime pine, eucalyptus, cork oak, holm oak) for January (minimum of emissions values) and for August (maximum of emissions values). Tables and charts present the monthly VOC’s emissions by specie and by compound.

Supplementary data to this article can be found online at https://doi.org/10.1016/j.envpol.2021.118088. | The commercial use and spread of silver nanoparticles (AgNPs) in freshwaters have greatly increased over the last decade. Both AgNPs and ionic silver (Ag+) released from nanoparticles are toxic to organisms and compromise ecosystem processes such as leaf litter decomposition. Yet little is known about how AgNPs affect multitrophic systems of interacting species. Furthermore, past work has focused on waterborne exposure with scarce attention given to effects mediated by the consumption of contaminated food. We assessed the importance of direct (via water) and indirect (via diet) AgNP exposure to a processing chain comprising leaf litter, fungi, a shredder (Gammarus pulex) and a collector (Habroleptoides confusa) in microcosms. Direct exposure to contaminated water for 15 days impaired microbial leaf decomposition by similar to 50% and leaf-associated fungal biomass by 10%. Leaf consumption was reduced by similar to 20% but only when G. pulex was exposed to silver via contaminated leaves. There was no effect on FPOM production. Ag+ could impose oxidative stress on the shredders and collectors independent of exposure route, as indicated by increased catalase and glutathione S-transferase activities and decreased superoxide dismutase activity. The activity of a neuronal enzyme (cholinesterase) in collectors, but not shredders, also decreased by almost 50% when the animals were indirectly exposed to AgNP. Our results show that AgNPs and Ag+ may disrupt detrital processing chains through direct and indirect exposure routes, even at low concentrations. This highlights the importance of AgNP exposure pathways to interconnected stream biota and ecosystem processes for realistic assessments of risks to freshwater ecosystems. | - We are grateful to Claudia Kuntz at the Chair of Soil Science of TU Berlin for Ag analyses and to Monika Degebrodt and Uta Mallok for assistance during the experiment and nutrient analyses, respectively. This work was supported by the Swiss National Science Foundation (SNF, 200020_134750/1) as part of the National Research Programme NRP 64 on Opportunities and Risks of Nanomaterials, the German Ac-ademic Exchange Service (DAAD, 57036658) , FEDER-POFC-COMPETE, the Portuguese Foundation for Science and Technology (PTDC/BIA-BMA/30922/2017, FCT-DAAD 2013-2014) , and a PhD fellowship to D. Batista (SFRH/BD/88181/2012) .