Cation exchange capacity of biochar: An urgent method modification.

Biochar, produced through pyrolysis of organic matter, is negatively charged, thus contributing to electrostatic adsorption of cations. However, due to its porous structure and contents of alkaline ashes, the determination of the cation exchange capacity (CEC) is challenging. Literature values for the CEC of biochar are surprisingly variable and are often poorly reproducible, suggesting methodological problems.

Multi-year double cropping biochar field trials in Nepal: Finding the optimal biochar dose through agronomic trials and cost-benefit analysis.

Poor water and nutrient retention are the major soil fertility limitations in the low productivity agricultural soils of Nepal. The addition of biochar to these soils is one way these hindrances can be overcome. In the present study, six different biochar doses (control, 5 t ha, 10 t ha, 15 t ha, 25 t ha and 40 t ha) were applied to a moderately acidic silty loam soil from Rasuwa, Nepal and the effects on soil physicochemical properties and maize and mustard yield over three years (i.

The potential of biochar in improving drainage, aeration and maize yields in heavy clay soils.

Heavy clay soils are globally widespread but their poor drainage and poor aeration limit their use for agriculture. This study was designed to test the effect of the amendment of biochar (BC) from woody shrubs on drainage/saturated hydraulic conductivity (Ksat), soil aeration/air capacity, available water capacity and biomass and grain yields of maize. In a field experiment, BC from Gliricidia sepium was applied in planting basins or rip lines at 2.

Fading positive effect of biochar on crop yield and soil acidity during five growth seasons in an Indonesian Ultisol.

Low fertility limits crop production on acidic soils dominating much of the humid tropics. Biochar may be used as a soil enhancer, but little consensus exists on its effect on crop yield. Here we use a controlled, replicated and long-term field study in Sumatra, Indonesia, to investigate the longevity and mechanism of the effects of two contrasting biochars (produced from rice husk and cacao shell, and applied at dosages of 5 and 15tha) on maize production in a highly acidic Ultisol (pH3.

Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison.

This work presents the results of an international interlaboratory comparison on ex situ passive sampling in sediments. The main objectives were to map the state of the science in passively sampling sediments, identify sources of variability, provide recommendations and practical guidance for standardized passive sampling, and advance the use of passive sampling in regulatory decision making by increasing confidence in the use of the technique. The study was performed by a consortium of 11 laboratories and included experiments with 14 passive sampling formats on 3 sediments for 25 target chemicals (PAHs and PCBs).

Limited mobility of dioxins near San Jacinto super fund site (waste pit) in the Houston Ship Channel, Texas due to strong sediment sorption.

Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal.

The presence and partitioning behavior of flame retardants in waste, leachate, and air particles from Norwegian waste-handling facilities.

Flame retardants in commercial products eventually make their way into the waste stream. Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment (WEEE), vehicles, digestate, glass, combustibles, bottom ash and fly ash.

Sorption, bioavailability and ecotoxic effects of hydrophobic organic compounds in biochar amended soils.

This work addresses the effect of biochar amendment to soil on contaminant sorption, bioavailability, and ecotoxicity. A distinction between positive primary amendment effects caused by reduced toxicity resulting from contaminant sorption, and negative secondary amendment effects of the biochars themselves was seen. Two biochars (one from high technology and one from low technology production processes) representing real world biochars were tested for the adsorption of pyrene, polychlorinated biphenyl (PCB) 52), and dichlorodiphenyldichloroethylene (p,p'-DDE).

Sequestration of Antimony on Calcite Observed by Time-Resolved Nanoscale Imaging.

Antimony, which has damaging effects on the human body and the ecosystem, can be released into soils, ground-, and surface waters either from ore minerals that weather in near surface environments, or due to anthropogenic releases from waste rich in antimony, a component used in batteries, electronics, ammunitions, plastics, and many other industrial applications. Here, we show that dissolved Sb can interact with calcite, a widespread carbonate mineral, through a coupled dissolution-precipitation mechanism. The process is imaged in situ, at room temperature, at the nanometer scale by using an atomic force microscope equipped with a flow-through cell.

Sulfur-modified rice husk biochar: A green method for the remediation of mercury contaminated soil.

Mercury (Hg) contamination of surface soils has increased by ~86Giga grams due to anthropogenic activities. There is an urgent need to find new, effective and preferably 'green' remediation technologies to protect human health and the environment. Sulfur-modification of sorbents can greatly enhance Hg sorption capacity - by forming low solubility HgS (cinnabar).

In situ benthic flow-through chambers to determine sediment-to-water fluxes of legacy hydrophobic organic contaminants.

Contaminated sediment can release hydrophobic organic contaminants (HOCs) and thereby act as a secondary source of primarily legacy hazardous substances to the water column. There is therefore a need for assessments of the release of HOCs from contaminated sediment for prioritization of management actions. In situ assessment of HOC sediment-to-water flux is currently done with (closed) benthic flux chambers, which have a sampling time exceeding one month.

The influence of permanently submerged macrophytes on sediment mercury distribution, mobility and methylation potential in a brackish Norwegian fjord.

Macrophytes are shown to affect the microbial activity in different aqueous environments, with an altering of the sediment cycling of mercury (Hg) as a potential effect. Here, we investigated how a meadow with permanently submerged macrophytes in a contaminated brackish fjord in southern Norway influenced the conditions for sulfate reducing microbial activity, the methyl-Hg (MeHg) production and the availability of MeHg. Historically discharged Hg from a chlor-alkali plant (60-80tons, 1947-1987) was evident through high Hg concentrations (491mgTot-Hgkg, 268μgMeHgkg) in intermediate sediment depths (10-20cm) outside of the meadow, with reduced concentrations within the meadow.

Laboratory versus field soil aging: Impact on DDE bioavailability and sorption.

Solid-phase microextraction (SPME), XAD, and the sequential supercritical fluid extraction (SFE) were used to assess the influence of aging of p,p'-DDE in a laboratory contaminated soil for up to 730 days. The end points determined were the freely dissolved concentration (C) using SPME, the potentially bioaccessible fraction (F, %) and the distribution of p,p'-DDE among fast, moderate, and slow desorbing soil sites determined by three sequentially stronger SFE conditions. C and F decreased during the first 35 days of aging by up to 40%.

A Constitutive Model for Soft Clays Incorporating Elastic and Plastic Cross-Anisotropy.

Natural clays exhibit a significant degree of anisotropy in their fabric, which initially is derived from the shape of the clay platelets, deposition process and one-dimensional consolidation. Various authors have proposed anisotropic elastoplastic models involving an inclined yield surface to reproduce anisotropic behavior of plastic nature. This paper presents a novel constitutive model for soft structured clays that includes anisotropic behavior both of elastic and plastic nature.

Monitoring alkylphenols in water using the polar organic chemical integrative sampler (POCIS): Determining sampling rates via the extraction of PES membranes and Oasis beads.

Polar organic chemical integrative samplers (POCIS) have previously been used to monitor alkylphenol (AP) contamination in water and produced water. However, only the sorbent receiving phase of the POCIS (Oasis beads) is traditionally analyzed, thus limiting the use of POCIS for monitoring a range of APs with varying hydrophobicity. Here a "pharmaceutical" POCIS was calibrated in the laboratory using a static renewal setup for APs (from 2-ethylphenol to 4-n-nonylphenol) with varying hydrophobicity (log K between 2.

Ranking REACH registered neutral, ionizable and ionic organic chemicals based on their aquatic persistency and mobility.

The contaminants that have the greatest chances of appearing in drinking water are those that are mobile enough in the aquatic environment to enter drinking water sources and persistent enough to survive treatment processes. Herein a screening procedure to rank neutral, ionizable and ionic organic compounds for being persistent and mobile organic compounds (PMOCs) is presented and applied to the list of industrial substances registered under the EU REACH legislation as of December 2014. This comprised 5155 identifiable, unique organic structures.

Toolset for assessment of natural recovery from legacy contaminated sediment: Case study of Pallanza Bay, Lake Maggiore, Italy.

The aim of this study was to develop a toolset that can be used by site managers to assess and monitor natural attenuation processes in sediments contaminated with legacy hydrophobic organic contaminants. The toolset is composed of sediment traps to measure quality and deposition rate of incoming sediment under different hydrodynamic conditions, sediment cores to show trends in sediment bed concentrations over time, and passive samplers attached to a porewater probe frame to assess the mobility of buried contaminants and possible contaminant flux from sediment. These three tools were used together for the first time to assess the mobility of dichlorodiphenyltrichloroethane (DDT) contaminants in sediment in Pallanza Bay, Lake Maggiore, Italy.

Enhanced biodegradation of PAHs in historically contaminated soil by M. gilvum inoculated biochar.

The inoculation of rice straw biochar with PAH-degrading Mycobacterium gilvum (1.27 × 10 ± 1.24 × 10 cell g), and the subsequent amendment of this composite material to PAHs contaminated (677 mg kg) coke plant soil, was conducted in order to investigate if would enhance PAHs biodegradation in soils.

Biochar from "Kon Tiki" flame curtain and other kilns: Effects of nutrient enrichment and kiln type on crop yield and soil chemistry.

Biochar application to soils has been investigated as a means of improving soil fertility and mitigating climate change through soil carbon sequestration. In the present work, the invasive shrub "Eupatorium adenophorum" was utilized as a sustainable feedstock for making biochar under different pyrolysis conditions in Nepal. Biochar was produced using several different types of kilns; four sub types of flame curtain kilns (deep-cone metal kiln, steel shielded soil pit, conical soil pit and steel small cone), brick-made traditional kiln, traditional earth-mound kiln and top lift up draft (TLUD).

Response of marine benthic fauna to thin-layer capping with activated carbon in a large-scale field experiment in the Grenland fjords, Norway.

A field experiment with thin-layer capping was conducted in the Grenland fjords, Norway, for remediation in situ of mercury and dioxin-contaminated sediments. Experimental fields at 30 and 95 m depth were capped with (i) powdered activated carbon (AC) mixed with clay (AC+cla`y), (ii) clay, and (iii) crushed limestone. Ecological effects on the benthic community and species-feeding guilds were studied 1 and 14 months after capping, and a total of 158 species were included in the analyses.

Monitoring chemical and biological recovery at a confined aquatic disposal site, Oslofjord, Norway.

The recovery of the confined aquatic disposal (CAD) facility located at Malmøykalven in Oslofjord, Norway, has been assessed using an array of field measurement techniques. These methods were used prior to the disposal of dredged sediments as well as during 3 annual postdisposal monitoring campaigns. Traditional sampling to assess chemical recovery indicates that an immediate reduction in total sediment concentrations and surface sediments can be characterized as having good quality.

Mixing and capping techniques for activated carbon based sediment remediation - Efficiency and adverse effects for Lumbriculus variegatus.

Activated carbon (AC) has been proven to be highly effective for the in-situ remediation of sediments contaminated with a wide range of hydrophobic organic contaminants (HOCs). However, adverse biological effects, especially to benthic organisms, can accompany this promising remediation potential. In this study, we compare both the remediation potential and the biological effects of several AC materials for two application methods: mixing with sediment (MIX) at doses of 0.

Bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons from (post-pyrolytically treated) biochars.

Bioaccessibility data of PAHs from biochar produced under real world conditions is scarce and the influence of feedstock and various post-pyrolysis treatments common in agriculture, such as co-composting or lacto-fermentation to produce silage fodder, on their bioavailability and bioaccessibility has hardly been studied. The total (C), and freely dissolved (i.e.

The mass flow and proposed management of bisphenol A in selected Norwegian waste streams.

Current initiatives for waste-handling in a circular economy favor prevention and recycling over incineration or landfilling. However, the impact of such a transition on environmental emissions of contaminants like bisphenol A (BPA) during waste-handling is not fully understood. To address this, a material flow analysis (MFA) was constructed for selected waste categories in Norway, for which the amount recycled is expected to increase in the future; glass, vehicle, electronic, plastic and combustible waste.