Bioremediation model for atrazine contaminated agricultural soils using phytoremediation (using Phaseolus vulgaris L.) and a locally adapted microbial consortium

The objective of the present study was to examine a biological model under greenhouse conditions for the bioremediation of atrazine contaminated soils. The model consisted in a combination of phytoremediation (using Phaseolus vulgaris L.) and rhizopheric bio-augmentation using native Trichoderma sp., and Rhizobium sp. microorganisms that showed no inhibitory growth at 10,000 mg L^?1 of herbicide concentration. 33.3 mg of atrazine 50 g^?1 of soil of initial concentration was used and an initial inoculation of 1 × 10⁹ UFC mL^?1 of Rhizobium sp. and 1 × 10⁵ conidia mL^?1 of Trichoderma sp. were set. Four treatments were arranged: Bean + Trichoderma sp. (B+T); Bean + Rhizobium sp. (BR); Bean + Rhizobium sp. + Trichoderma sp. (B+R+T) and Bean (B). 25.51 mg of atrazine 50 g^?1 of soil (76.63%) was removed by the B+T treatment in 40 days (a = 0.050, Tukey). This last indicate that the proposed biological model and methodology developed is useful for atrazine contaminated bioremediation agricultural soils, which can contribute to reduce the effects of agrochemical abuse.     

Determination of glyoxal and methylglyoxal in atmospheric particulate matter by 2,4-dinitrophenylhydrazine derivatisation

A simple and rapid method has been optimised to determine glyoxal and methylglyoxal in atmospheric particulate matter by extraction and derivatisation with 2,4-dinitrophenylhydrazine solutions. Minimal sample preparation was required by mixing a portion of filter charged with atmospheric particulate matter with 5?mL of a saturated solution of 2,4-dinitrophenylhydrazine (1.6?g?L^?1) in acetonitrile and acidified by H₂SO₄ (50?µL?L^?1). Chromatographic analyses were carried out 1?h after derivatisation solution was mixed. Finally, the proposed method was applied to quantify these dicarbonyls in atmospheric particulate matter samples, which were obtained as part of a large field study to characterise atmospheric aerosol from a rural area of Madrid. Glyoxal concentrations averaged 0.24?ng?m^?3, whereas mean values of methyl glyoxal were around 0.95?ng?m^?3. Methyl glyoxal levels showed a clear relationship with the particulate matter levels, whereas glyoxal data did not show such a correlation. This could indicate that both dicarbonyls come from different sources.     

Differential activity of non-fluorinated and fluorinated analogues of the European corn borer pheromone

Summary.  The differing antagonist activity of (Z)-13-hexadecen-2-one (Z11 – 14 :MK, 1) and its 1,1,1-trifluoro derivative (Z11 –14 :TFMK, 2), two closely related analogues of the European corn borer pheromone Ostrinia nubilalis (Z strain), and their rationale is reported. Both chemicals exhibited some electrophysiological activity, and topical application of 10 pg of pheromone analogue on male antennae was sufficient to induce significantly lower depolarization responses to the pheromone versus untreated insects. In a wind tunnel, the number of European corn borer males attracted to sources containing mixtures of 1 + pheromone in ratios ≥ 1 :1 was significantly lower than the number attracted to a source containing pheromone alone. Source contact behaviour was dramatically impaired when the 1 + pheromone blend reached a ratio of 10 :1, in which only 2% of males displayed source contact in the presence of antagonist. When compound 1 was present at the source, males usually flew upwind with occasional downwind reversals; when compound 2 was present at the lure, males performed wider crosswind reversals, with little progress toward the source. In the field, traps baited with mixtures of both compounds with the pheromone in ratios of 5 :1 and 10 :1 elicited a significantly decreased number of male catches. In esterase inhibition assays, compound 2 was a potent inhibitor (IC₅₀ = 70 nM), whereas the non-fluorinated compound 1 was not. The different activity of both compounds is presumed to be due to different mechanisms of action; considerations for using methyl ketone analogues as new behavioural antagonists of the pheromone are outlined.     

Disposable diapers biodegradation by the fungus Pleurotus ostreatus

This research assesses the feasibility of degrading used disposable diapers, an important component (5-15% in weight) of urban solid waste in Mexico, by the activity of the fungus Pleurotus ostreatus, also known as oyster mushroom. Disposable diapers contain polyethylene, polypropylene and a super absorbent polymer. Nevertheless, its main component is cellulose, which degrades slowly. P. ostreatus has been utilized extensively to degrade cellulosic materials of agroindustrial sources, using in situ techniques. The practice has been extended to the commercial farming of the mushroom. This degradation capacity was assayed to reduce mass and volume of used disposable diapers. Pilot laboratory assays were performed to estimate the usefulness of the following variables on conditioning of used diapers before they act as substrate for P. ostreatus: (1) permanence vs removal of plastic cover; (2) shredding vs grinding; (3) addition of grape wastes to improve structure, nitrogen and trace elements content. Wheat straw was used as a positive control. After 68 days, decrease of the mass of diapers and productivity of fungus was measured. Weight and volume of degradable materials was reduced up to 90%. Cellulose content was diminished in 50% and lignine content in 47%. The highest efficiency for degradation of cellulosic materials corresponded to the substrates that showed highest biological efficiency, which varied from 0% to 34%. Harvested mushrooms had good appearance and protein content and were free of human disease pathogens. This research indicates that growing P. ostreatus on disposable diapers could be a good alternative for two current problems: reduction of urban solid waste and availability of high protein food sources.     

Distribution of volatile organic compounds in Madrid (Spain)

From November 1995 to October 1996, airborne concentrations of VOCs were measured in the Madrid area to study the organic pollution in general, and the correlation between different pollutants in relation to such parameters as location and season. Mean concentrations for up to 90 compounds were measured at four test sites, including both urban and suburban areas. At the urban sites, maximum concentrations occurred in the autumn and winter, whereas minimum concentrations were reached in summer and spring. Similar changes were obtained for the lesscontaminated site located in the SE of the city, whereas a different pattern was found at the site in the NW of the city due to meteorological aspects. Mean levels of hydrocarbons in Madrid were quite similar to those found in other European cities. Chemometrical techniques were applied to the set of data in order to assess the influence of such factors as traffic, temperature and seasonal variations on the VOC levels.     

SOIL ZINC CONTAMINATION FROM CORROSION OF GALVANIZED STRUCTURES

The present work relates to galvanized structures with several years of time life subjected to atmospheric corrosion, like galvanized high tension steel pylons. The mass and fate of zinc released is evaluated both via empirical and experimental procedures. The corrosion rate determination requested atmospheric condition characterization, especially for SO 2 concentration and experimental activities focused on soil sampling around pylons. The soil zinc content, total and exchangeable, is determinates by different analytical procedures. The zinc diffusion in environment and the zinc extension under the top soil is evaluated using 1-dimensional mathematical model for miscible species in porous soil.     

Assessing the effects of pseudo-absences on predictive distribution model performance

Modelling species distributions with presence data from atlases, museum collections and databases is challenging. In this paper, we compare seven procedures to generate pseudo-absence data, which in turn are used to generate GLM-logistic regressed models when reliable absence data are not available. We use pseudo-absences selected randomly or by means of presence-only methods (ENFA and MDE) to model the distribution of a threatened endemic Iberian moth species (Graellsia isabelae). The results show that the pseudo-absence selection method greatly influences the percentage of explained variability, the scores of the accuracy measures and, most importantly, the degree of constraint in the distribution estimated. As we extract pseudo-absences from environmental regions further from the optimum established by presence data, the models generated obtain better accuracy scores, and over-prediction increases. When variables other than environmental ones influence the distribution of the species (i.e., non-equilibrium state) and precise information on absences is non-existent, the random selection of pseudo-absences or their selection from environmental localities similar to those of species presence data generates the most constrained predictive distribution maps, because pseudo-absences can be located within environmentally suitable areas. This study shows that if we do not have reliable absence data, the method of pseudo-absence selection strongly conditions the obtained model, generating different model predictions in the gradient between potential and realized distributions.     

Trace element biomonitoring using mosses in urban areas affected by mud volcanoes around Mt. Etna. The case of the Salinelle, Italy

Trace element impact was assessed using mosses in a densely inhabited area affected by mud volcanoes. Such volcanoes, locally called Salinelle, are phenomena that occur around Mt. Etna (Sicily, Italy) and are interpreted as the surface outflow of a hydrothermal system located below Mt. Etna, releasing sedimentary fluids (hydrocarbons and NaCl brines) along with magmatic gases (mainly CO(2) and He). To date, scarce data are available about the presence of trace elements, and no biomonitoring campaigns are reported about the cumulative effects of such emissions. In this study, concentrations of Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn were detected in the moss Bryum argenteum, in soil and water. Results showed that the trace element contribution of the Salinelle to the general pollution was significant for Al, Mn, Ni, and Zn. The comparison of trace concentrations in mosses from Salinelle and Etna showed that the mud volcanoes release a greater amount of Al and Mn, whereas similar values of Ni were found. Natural emissions of trace elements could be hazardous in human settlements, in particular, the Salinelle seem to play an important role in environmental pollution.     

Emission factors of atmospheric and climatic pollutants from crop residues burning

Biomass burning is a common agricultural practice, because it allows elimination of postharvesting residues; nevertheless, it involves an inefficient combustion process that generates atmospheric pollutants emission, which has implications on health and climate change. This work focuses on the estimation of emission factors (EFs) of PM_2.5, PM₁₀, organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), carbon dioxide (CO₂), and methane (CH₄) of residues from burning alfalfa, barley, beans, cotton, maize, rice, sorghum, and wheat in Mexico. Chemical characteristics of the residues were determined to establish their relationship with EFs, as well as with the modified combustion efficiency (MCE). Essays were carried out in an open combustion chamber with isokinetic sampling, following modified EPA 201-A method. EFs did not present statistical differences among different varieties of the same crop, but were statistically different among different crops, showing that generic values of EFs for all the agricultural residues can introduce significant uncertainties when used for climatic and atmospheric pollutant inventories. EFs of PM_2.5 ranged from 1.19 to 11.30 g kg^?1, and of PM₁₀ from 1.77 to 21.56 g kg^?1. EFs of EC correlated with lignin content, whereas EFs of OC correlated inversely with carbon content. EFs of EC and OC in PM_2.5 ranged from 0.15 to 0.41 g kg^?1 and from 0.33 to 5.29 g kg^?1, respectively, and in PM₁₀, from 0.17 to 0.43 g kg^?1 and from 0.54 to 11.06 g kg^?1. CO₂ represented the largest gaseous emissions volume with 1053.35–1850.82 g kg^?1, whereas the lowest was CH₄ with 1.61–5.59 g kg^?1. CO ranged from 28.85 to 155.71 g kg^?1, correlating inversely with carbon content and MCE. EFs were used to calculate emissions from eight agricultural residues burning in the country during 2016, to know the potential mitigation of climatic and atmospheric pollutants, provided this practice was banned.

Implications: The emission factors of particles, short-lived climatic pollutants, and atmospheric pollutants from the crop residues burning of eight agricultural wastes crops, determined in this study using a standardized method, provides better knowledge of the emissions of those species in Latin America and other developing countries, and can be used as inputs in air quality models and climatic studies. The EFs will allow the development of more accurate inventories of aerosols and gaseous pollutants, which will lead to the design of effective mitigation strategies and planning processes for sustainable agriculture.