A comparative study of the properties of industrially produced humic substances

Humic substances (HSs) are produced industrially in large quantities from low rank coal, weathered coal, peat, also from soils, composts and other sources. Considering that the applications of industrially produced HSs also include food, pharmaceutical applications and environmental technologies, it is important to evaluate their composition and quality and to identify their sources. The aim of the present study is to compare the properties of industrially produced HS samples. HSs were characterised using spectroscopic and other methods. For the identification of origin of HSs, different methods can be used, such as elemental analysis and ratios of light stable isotopes. The results of the study indicate that many industrially produced HSs are of poor quality (low concentration of basic substance, admixture of undesirable substances, pollutants, no quality indications). In this situation, rigorous quality control should be implemented, providing detailed characteristics of the product. The composition of materials suggested for agricultural applications has not been analysed much. Most of the studied materials were designated as HAs, followed by fulvic acids (FAs) and HSs. However, an analysis of the humic matter types indicates that the majority of substances offered on the market are in fact mixtures of HAs and FAs; so, it would be more appropriate to designate them as HSs or their salts. This study identifies the main quality problems of industrially produced humic substances: 1) lack of strict quality indicators, 2) absence of indication of source materials/origins of HSs

Characterization of Coal Particles in the Soil of a Former Rail Yard and Urban Brownfield: Liberty State Park, Jersey City (NJ), USA

From the 1850\u27s until the 1960\u27s, the Central Railroad of New Jersey was among several major railways shipping anthracite and bituminous coal to the New York City area, transferring coal from railcar to barge at its extensive rail yard and port facility in Jersey City. The 490 ha Liberty State Park was developed on the site after the rail yard closed, but a ca. 100 ha brownfield zone within the park remains off limits to visitors pending future remediation. As part of an environmental forensic and industrial archeological investigation of this zone, the present study characterizes anthracite and bituminous coal particles present in abundance in the soil by scanning electron microscopy (SEM) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). A simple pretreatment procedure employing density separation improved the analytical results. This detailed information about the nature of contaminants at the site will help to inform the remediation effort in the public interest

Plant–soil feedbacks of exotic plant species across life forms: a meta-analysis

Invasive exotic plant species effects on soil biota and processes in their new range can promote or counteract invasions via changed plant–soil feedback interactions to themselves or to native plant species. Recent meta-analyses reveale that soil influenced by native and exotic plant species is affecting growth and performance of natives more strongly than exotics. However, the question is how uniform these responses are across contrasting life forms. Here, we test the hypothesis that life form matters for effects on soil and plant–soil feedback. In a meta-analysis we show that exotics enhanced C cycling, numbers of meso-invertebrates and nematodes, while having variable effects on other soil biota and processes. Plant effects on soil biota and processes were not dependent on life form, but patterns in feedback effects of natives and exotics were dependent on life form. Native grasses and forbs caused changes in soil that subsequently negatively affected their biomass, whereas native trees caused changes in soil that subsequently positively affected their biomass. Most exotics had neutral feedback effects, although exotic forbs had positive feedback effects. Effects of exotics on natives differed among plant life forms. Native trees were inhibited in soils conditioned by exotics, whereas native grasses were positively influenced in soil conditioned by exotics. We conclude that plant life form matters when comparing plant–soil feedback effects both within and between natives and exotics. We propose that impact analyses of exotic plant species on the performance of native plant species can be improved by comparing responses within plant life form

Environmental Forensic Characterization of Former Rail Yard Soils Located Adjacent to the Statue of Liberty in the New York/New Jersey Harbor

Identifying inorganic and organic soil contaminants in urban brownfields can give insights into the adverse effects of industrial activities on soil function, ecological health, and environmental quality. Liberty State Park in Jersey City (N.J., USA) once supported a major rail yard that had dock facilities for both cargo and passenger service; a portion remains closed to the public, and a forest developed and spread in this area. The objectives of this study were to: 1) characterize the organic and inorganic compounds in Liberty State Park soils and compare the findings to an uncontaminated reference site (Hutcheson Memorial Forest); and 2) identify differences between the barren low-functioning areas and the forested high-functioning areas of the brownfield. Soil samples were solvent-extracted, fractionated, and analyzed by gas chromatography–mass spectrometry and subjected to loss-on-ignition, pyrolysis-gas chromatography–mass spectrometry, inductively-coupled-plasma mass spectrometry, and optical microscopy analyses. Compared to soil from the reference site, the forested soils in Liberty State Park contained elevated percentages of organic matter (30–45%) and more contaminants, such as fossil-fuel-derived hydrocarbons and coal particles. Microscopy revealed bituminous and anthracite coal, coke, tar/pitch, and ash particles. Barren and low-functioning site 25R had a similar organic contaminant profile but contained a higher metal load than other Liberty State Park sites and also lacked higher plant indicators. These can obscure the signatures of contaminants, and data from adjacent barren and vegetated sites are valuable references for soils studies. A deeper understanding of the chemistry, biochemistry, and ecology of barren soils can be leveraged to prevent land degradation and to restore dysfunctional and phytotoxic soils

Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity

The Sudbury Neutrino Observatory (SNO) has precisely determined the total active (nu_x) 8B solar neutrino flux without assumptions about the energy dependence of the nu_e survival probability. The measurements were made with dissolved NaCl in the heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27 (stat) +/- 0.38 (syst) x10^6 cm^{-2}s^{-1}, in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Delta m^{2} = 7.1^{+1.2}_{-0.6}x10^{-5} ev^2 and theta = 32.5^{+2.4}_{-2.3} degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.Comment: Submitted to Phys. Rev. Let

Electron Antineutrino Search at the Sudbury Neutrino Observatory

Upper limits on the \nuebar flux at the Sudbury Neutrino Observatory have been set based on the \nuebar charged-current reaction on deuterium. The reaction produces a positron and two neutrons in coincidence. This distinctive signature allows a search with very low background for \nuebar's from the Sun and other potential sources. Both differential and integral limits on the \nuebar flux have been placed in the energy range from 4 -- 14.8 MeV. For an energy-independent \nu_e --> \nuebar conversion mechanism, the integral limit on the flux of solar \nuebar's in the energy range from 4 -- 14.8 MeV is found to be \Phi_\nuebar <= 3.4 x 10^4 cm^{-2} s^{-1} (90% C.L.), which corresponds to 0.81% of the standard solar model 8B \nu_e flux of 5.05 x 10^6 cm^{-2} s^{-1}, and is consistent with the more sensitive limit from KamLAND in the 8.3 -- 14.8 MeV range of 3.7 x 10^2 cm^{-2} s^{-1} (90% C.L.). In the energy range from 4 -- 8 MeV, a search for \nuebar's is conducted using coincidences in which only the two neutrons are detected. Assuming a \nuebar spectrum for the neutron induced fission of naturally occurring elements, a flux limit of Phi_\nuebar <= 2.0 x 10^6 cm^{-2} s^{-1}(90% C.L.) is obtained.Comment: submitted to Phys. Rev.

Constraints on Nucleon Decay via "Invisible" Modes from the Sudbury Neutrino Observatory

Data from the Sudbury Neutrino Observatory have been used to constrain the lifetime for nucleon decay to ``invisible'' modes, such as n -> 3 nu. The analysis was based on a search for gamma-rays from the de-excitation of the residual nucleus that would result from the disappearance of either a proton or neutron from O16. A limit of tau_inv > 2 x 10^{29} years is obtained at 90% confidence for either neutron or proton decay modes. This is about an order of magnitude more stringent than previous constraints on invisible proton decay modes and 400 times more stringent than similar neutron modes.Comment: Update includes missing efficiency factor (limits change by factor of 2) Submitted to Physical Review Letter

2‐Methyltetrahydrofuran (2‐MeTHF) as a versatile green solvent for the synthesis of amphiphilic copolymers via ROP, FRP, and RAFT tandem polymerizations

2‐methyltetrahydrofuran (2‐MeTHF) is a readily available, inexpensive, neoteric, bio‐based solvent. It has been adopted across a wide range of chemical processes including the batch manufacture of fine chemicals, enzymatic polycondensations and ring opening polymerizations. To reduce the environmental burden related to the synthesis of pharmaceutical‐grade polymers based on lactide and caprolactone, we envisaged the use of 2‐MeTHF. For the first time, we combined a series of metal‐free and enzymatic ROPs with free radical and controlled RAFT polymerizations (carried out separately and in tandem) in 2‐MeTHF, in order to easily tune the chemistry and the architecture of the final polymers. After a simple purification, the amphiphilic polymers were formulated into nanoparticles and tested for their cytocompatibility in three model cell lines, to assess their application as potential polymeric excipients for nanomedicines

A ‘greener’ one-pot synthesis of monoterpene-functionalised lactide oligomers

© 2020 Elsevier Ltd In this work we aimed to achieve a totally sustainable Ring Opening Polymerisation (ROP) process, by harmonising the use of naturally occurring or derivable initiators and the green solvent 2-Methyltetrahydrofuran (2-MeTHF). First, a library of novel monoterpene-alcohols and existing terpenoids was used to provide renewably sourced initiators for a metal-free ROP synthetic step. A number of these initiators are derived from waste materials, further improving their sustainability. Secondly, we selected lactide (LA) as a monomer, because not only is it derived from biomass, but its resultant polymers are biocompatible and biodegradable. Interestingly, these new polymers self-assembled in water producing well defined, biocompatible nanoparticles (NPs) via direct nanoprecipitation without the use of additional stabilisers. We have highlighted a novel and promising (ROP) approach to produce biodegradable, amphiphilic ester-based macromolecules, based on lactide and terpenes (as initiators) in a green solvent, 2-MeTHF thus reducing solvent toxicity in an efficient, simple and sustainable new synthesis. The monoterpenes may provide a highly functionalisable and bio-renewable toolbox for a new generation of ROP initiators