Carbon and nitrogen stocks and nitrogen mineralization in organically managed soils amended with composted manures

The use of composted manures and of legumes in crop rotations may control the quality and quantity of soil organic matter and may affect nutrient retention and recycling. We studied soil organic C and N stocks and N mineralization in organically and conventionally managed dryland arable soils. We selected 13 extensive organic fields managed organically for 10 yr or more as well as adjacent fields managed conventionally. Organic farmers applied composted manures ranging from 0 to 1380 kg C ha yr and incorporated legumes in crop rotations. In contrast, conventional farmers applied fresh manures combined with slurries and/or mineral fertilizers ranging from 200 to 1900 kg C ha yr and practiced a cereal monoculture. Despite the fact that the application of organic C was similar in both farming systems, organically managed soils showed higher C and similar N content and lower bulk density than conventionally managed soils. Moreover, organic C stocks responded to the inputs of organic C in manures and to the presence of legumes only in organically managed soils. In contrast, stocks of organic N increased with the inputs of N or C in both farming systems. In organically managed soils, organic N stocks were less mineralizable than in conventional soils. However, N mineralization in organic soils was sensitive to the N fixation rates of legumes and to application rate and C/N ratio of the organic fertilizers.     

Electrochemical incineration of indigo. A comparative study between 2D (plate) and 3D (mesh) BDD anodes fitted into a filter-press reactor

This paper compares the performance of 2D (plate) and 3D (mesh) boron-doped diamond (BDD) electrodes, fitted into a filter-press reactor, during the electrochemical incineration of indigo textile dye as a model organic compound in chloride medium. The electrolyses were carried out in the FM01-LC reactor at mean fluid velocities between 0.9?≤?u?≤?10.4 and 1.2?≤?u?≤?13.9 cm s^?1 for the 2D BDD and the 3D BDD electrodes, respectively, at current densities of 5.63 and 15 mA cm^?2. The oxidation of the organic matter was promoted, on the one hand, via the physisorbed hydroxyl radicals (BDD(^●OH)) formed from water oxidation at the BDD surface and, on the other hand, via active chlorine formed from the oxidation of chloride ions on BDD. The performance of 2D BDD and 3D BDD electrodes in terms of current efficiency, energy consumption, and charge passage during the treatments is discussed.     

Characterization of complex lipid mixtures in contaminant exposed JEG-3 cells using liquid chromatography and high-resolution mass spectrometry

The aim of this study was to develop a method based on ultra high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS) for lipid profiling in human placental choriocarcinoma (JEG-3) cells. Lipids were solid–liquid extracted from JEG-3 cells using a solution of chloroform/methanol (2:1, v/v) in a simple procedure requiring minimal sample alteration. Simultaneous separation of complex lipid mixtures in their major classes was achieved with a reversed-phase (C₈) UHPLC column and a mobile phase containing methanol with 1 mM ammonium formate and 0.2 % formic acid (A)/water with 2 mM ammonium formate and 0.2 % formic acid (B). Lipids were characterized using time-of-flight (TOF) and Orbitrap under full scan and positive electrospray ionization mode with both analyzers. A total of 178 species of lipids, including 37 phosphatidylcholines (PC), 32 plasmalogen PC, 9 lyso PC, 4 lyso plasmalogen PC, 30 triacylglycerols, 22 diacylglycerols, 7 cholesterol esters, 25 phosphatidylethanolamines, and 12 sphingomyelins, were identified using TOF and Orbitrap. The identification of all lipid classes was based on exact mass characterization with an error < 5 ppm. The developed methodology was applied to study lipid alterations in human placental cells against the exposure to perfluorinated chemicals (PFCs) and tributyltin (TBT).     

Food sources of arsenic in pregnant Mediterranean women with high urine concentrations of this metalloid

Seafood consumption provides a significant amount of arsenic, although in its organic, nontoxic forms. Mediterranean populations may incorporate high levels of this metalloid as a consequence of seafood consumption. In the present study, the significance of this input among pregnant women from a Mediterranean city (Sabadell, Catalonia, Spain) is assessed. Total urinary arsenic was analyzed in 489 pairs of urine samples, corresponding to the 12th and 32th weeks of pregnancy. Association of arsenic content with seafood and other dietary items were studied. Geometric mean concentrations were 34 and 37 μg/g creatinine during the first and third trimesters, respectively. The observed concentrations were similar to those reported in studies from other Mediterranean countries. The differences between both periods were not statistically significant. The only dietary factor significantly and positively associated with total urinary arsenic in both series of samples was seafood, particularly lean fish. Moreover, lean fish consumption during both periods was found to be the main determinant for differences in levels of arsenic between the first and third trimesters, which confirms the association between high levels of total urinary arsenic and seafood consumption.     

Biological sweetening of energy gases mimics in biotrickling filters

Removal of hydrogen sulfide from waste and energy-rich gases is required, not only because of environmental health and safety reasons, but also because of operational reasons if such gases have to be used for energy generation. A biotrickling filter for the removal of ultra-high concentrations of H2S from oxygen-poor gases is proposed and studied in this work. Two laboratory-scale biotrickling filters were used to study the startup period and to determine the long-term performance of the gas sweetening process. The inlet H2S concentration ranged from 900 to 12000ppmv and two different packing materials were investigated. There was no toxicity effect observed even at a the highest H2S concentration, and maximum elimination capacities of 280 and 250g H2Sm(-3)h(-1) were obtained at gas contact times of 167 and 180s, respectively. Elemental sulfur and sulfate were found to be the most abundant end-products of the biological oxidation of sulfide when operated under microaerophilic conditions. The biotrickling filter was able to quickly recover its nominal performance after different load increases and system shutdowns simulating field operation. The results reported here show that biotreatment can be an interesting alternative to conventional gas sweetening systems normally used for such applications.     

Potential use of feebate systems to foster environmentally sound urban waste management

Waste treatment facilities are often shared among different municipalities as a means of managing wastes more efficiently. Usually, management costs are assigned to each municipality depending on the size of the population or total amount of waste produced, regardless of important environmental aspects such as per capita waste generation or achievements in composting or recycling. This paper presents a feebate (fee+rebate) system aimed to foster urban waste reduction and recovery. The proposal suggests that municipalities achieving better results in their waste management performance (from an ecological viewpoint) be recompensated with a rebate obtained from a fee charged to those municipalities that are less environmentally sound. This is a dynamic and flexible instrument that would positively encourage municipalities to reduce waste whilst increasing the recycling.     

The use of a high-FeO olivine rock as a redox buffer in a nuclear waste repository

Due to the higher stability of the spent nuclear fuel (mainly composed of UO2) under reducing conditions, and in order to enhance the retention/retardation of some key radionuclides, the olivine rock from the Lovasj?rvi intrusion has been proposed as a potential redox-active backfill-additive in deep high-level nuclear waste (HLNW) repositories. In this work, two different approaches have been undertaken in order to establish the redox buffer capacity of olivine rock: (1) The capacity of the rock to respond to changes in pH or pe has been demonstrated and the final (pH, pe) coordinates agree with the control exerted by the system Fe(II)/Fe(III). (2) The rate of consumption of oxygen has been determined at different pH values. These rates are higher than the ones reported in the literature for other solids, what would point to the possibility of using this rock as an additive to the backfill material in a HLNW.