The molecular composition of humic substances extracted from green composts and their potential for soil remediation

Humic substances play empirically several essential functions in biogeochemical cycles such as storage of carbon, pollutants, nutrients and water, yet the underlying mechanisms remain poorly known because their precise molecular structure is largely unknown so far. Here, we extracted humic substances from biomass waste of bell pepper, fennel, artichoke, coffee ground, coffee husks, and nursery residues. We analyzed humic extracts by ultra-high resolution Orbitrap Fusion Lumos Tribrid 1 M mass spectrometry, using both positive photoionization and negative electrospray ionization modes, and by ¹³C cross polarization/magic angle spinning nuclear magnetic resonance spectroscopy. We identified 5000–7000 unique organic compounds in humic substances by integrating photoionization with electrospray ionization. The chemical distribution of all components was depicted by nuclear magnetic resonance. Humic substances from green composts are composed by a wide variety of hydrophilic and hydrophobic moieties, thus providing the required biosurfactant properties for effective soil washing capacities, with carboxyl-rich alicyclic molecules, fatty acids, and phenolic acids as major constituents. Overall, our findings provide a major insight in the molecular structure of humic substances, thus opening research on mechanisms ruling the origin, fate and behavior of humic substances.

     

Polycyclic aromatic hydrocarbons in Mullus surmuletus from the Catania Gulf (Sicily,Italy): distribution and potential health risks

Environmental Science and Pollution Research - Different specimens of Mullus surmuletus from the Catania Gulf (Sicily) were sampled and analysed for the quantification of 16 priority polycyclic...     

FT-IR spectra of humic substances extracted with dipolar aprotic solvents

Dipolar aprotic solvents (DMSO, DMF and Acetone) in mixtures with dilute HCl extract humic substances by an intermolecular H-bonds disruption mechanism. FT-IR spectra of extracts and difference spectra of unpurified and purified material and thermogravimetric analysis showed that dipolar aprotic solvents produce humic substances with low contents of inorganic impurities and structurally different from common extractants. DMSO and Acetone extract humus particurally rich in aliphatic and proteinaceous components as compared to common extractant.     

Increased Sequestration of Organic Carbon in Soil by Hydrophobic Protection

 The impact of soil organic carbon dynamics on the global carbon cycle is still largely uncertain despite studies of agricultural activities and control emissions of greenhouse gases to the earth's atmosphere. Improved knowledge of organic matter dynamics should lead to reduction in CO₂ emissions. We used stable carbon isotope analysis to detect small changes in organic carbon storage and turnover upon soil treatments with a ¹³C-labeled aliphatic alcohol previously partitioned into soluble humic substances of varying hydrophobicity. We found that labeled organic carbon is increasingly protected from mineralization with increased hydrophobic character of humic matter. The stabilization of organic carbon by hydrophobic protection significantly reduced decomposition during incubation time in soil. Hydrophobic protection can become an useful tool to limit decomposition of fresh organic matter in soil and thus reduce CO₂ emission from agricultural soils on a global scale. Received: 1 March 1999 / Accepted in revised form: 16 June 1999     

Toward a high-rate enhanced biological phosphorus removal process in a membrane-assisted bioreactor.

A membrane enhanced biological phosphorus removal (MEBPR) process was studied to determine the impact of hydraulic retention time (HRT) and solids retention time (SRT) on the removal of chemical oxygen demand (COD), nitrogen, and phosphorus from municipal wastewater. The MEBPR process was capable of delivering complete nitrification independent of the prevailing operating conditions, whereas a significant improvement in COD removal efficiency was observed at longer SRTs. In the absence of carbon-limiting conditions, the MEBPR process was able to achieve low phosphorus concentrations in the effluent at increasingly higher hydraulic loads, with the lowest HRT being 5 hours. The MEBPR process was also able to maintain optimal phosphorus removal when the SRT was increased from 12 to 20 days. However, at higher suspended solids concentrations, a substantial increase was observed in carbon utilization per unit mass of phosphorus removed from the influent. These results offer critical insights to the application of membrane technology for biological nutrient removal systems.     

Prenatal detection of monosomy 21 mosaicism

We report a case of chromosomal mosaicism for monosomy 21 revealed in amniotic fluid cell culture. Ultrasound examination at 19 weeks' gestation showed in utero growth retardation and a complex cardiac malformation. A repeated amniocentesis confirmed the presence of monosomy 21 mosaicism. In view of the sonographically detected fetal abnormalities, termination of pregnancy was elected.     

Evaluation of mercury biogeochemical cycling at the sediment–water interface in anthropogenically modified lagoon environments

The Marano and Grado Lagoon is well known for being contaminated by mercury(Hg) from the Idrija mine(Slovenia) and the decommissioned chlor-alkali plant of Torviscosa(Italy).Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments(up to 6.81 μg/g)showed a slight variability with depth, whereas the highest methylmercury(MeHg) values(up to 10 ng/g) were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally(from 0.1 and 17% of dissolved Hg(DHg)) with the highest concentrations in summer. DHg diffusive effluxes higher(up to 444 ng/m~2/day) than those reported in the open lagoon(~ 95 ng/m~2/day), whereas DMeHg showed influxes in the fish farm(up to-156 ng/m~2/day). The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.     

Early detection and evaluation of waste through sensorized containers for a collection monitoring application

The present study describes a novel application for use in the monitoring of municipal solid waste, based on distributed sensor technology and geographical information systems. Original field testing and evaluation of the application were carried out in Pudong, Shanghai (PR China).The local waste management system in Pudong features particular requirements related to the rapidly increasing rate of waste production. In view of the fact that collected waste is currently deployed to landfills or to incineration plants within the context investigated, the key aspects to be taken into account in waste collection procedures include monitoring of the overall amount of waste produced, quantitative measurement of the waste present at each collection point and identification of classes of material present in the collected waste. The case study described herein focuses particularly on the above mentioned aspects, proposing the implementation of a network of sensorized waste containers linked to a data management system.Containers used were equipped with a set of sensors mounted onto standard waste bins. The design, implementation and validation procedures applied are subsequently described. The main aim to be achieved by data collection and evaluation was to provide for feasibility analysis of the final device. Data pertaining to the content of waste containers, sampled and processed by means of devices validated on two purpose-designed prototypes, were therefore uploaded to a central monitoring server using GPRS connection. The data monitoring and management modules are integrated into an existing application used by local municipal authorities.A field test campaign was performed in the Pudong area. The system was evaluated in terms of real data flow from the network nodes (containers) as well as in terms of optimization functions, such as collection vehicle routing and scheduling. The most important outcomes obtained were related to calculations of waste weight and volume. The latter data were subsequently used as parameters for the routing optimization of collection trucks and material density evaluation.     

The free energy and information embodied in the amino acid chains of organisms

It is generally accepted as a useful and workable hypothesis that when an ecosystem receives an inflow of exergy (energy that can do work) it will utilize this flow of exergy to move as far away from thermodynamic equilibrium as possible after the exergy (energy) for maintenance has been covered. If more combinations of system components including organisms are offered, the combination of components and processes that will bring the system most away from thermodynamic equilibrium will win.The amino acid sequences of the proteins e.g. enzymes determine and control the life processes of the organisms and may be viewed as information sensu lato. The free energy of oxidation of the amino acids and the peptide bonds of the cell enzymes expresses therefore the exergy content, eco-exergy or work capacity that the information contributes to “moving further away from thermodynamic equilibrium”. In this paper eco-exergy is calculated and plotted versus the β-values (a measure of the information contained in the genome) for different organisms. The eco-exergy density was previously (see [J?rgensen et al., 1995] and [J?rgensen et al., 2005]) proposed to be calculated as the summation of the product of the β-values representing the information of the genome multiplied by the concentrations of the respective ecosystem components. This analysis shows a strong correlation between the β-values and free energy released when oxidizing the enzymes. The β-values can therefore be assumed to represent the free energy that the organisms have invested in genetic information.