Importance of inner-sphere P-O-Fe bonds in natural and synthetic mineral-organic associations.

Sorption of organic molecules on mineral surfaces can occur through several binding mechanisms of varying strength. Here, we investigated the importance of inner-sphere P-O-Fe bonds in synthetic and natural mineral-organic associations. Natural organic matter such as water extracted soil organic matter (WESOM) and extracellular polymeric substances (EPS) from liquid bacterial cultures were adsorbed to goethite and examined by FTIR spectroscopy and P K-edge NEXAFS spectroscopy.

Crop genetic diversity uncovers metabolites, elements, and gene networks predicted to be associated with high plant biomass yields in maize.

Rapid population growth and increasing demand for food, feed, and bioenergy in these times of unprecedented climate change require breeding for increased biomass production on the world's croplands. To accelerate breeding programs, knowledge of the relationship between biomass features and underlying gene networks is needed to guide future breeding efforts. To this end, large-scale multiomics datasets were created with genetically diverse maize lines, all grown in long-term organic and conventional cropping systems.

Maize Field Study Reveals Covaried Microbiota and Metabolic Changes in Roots over Plant Growth.

Plant roots are colonized by microorganisms from the surrounding soil that belong to different kingdoms and form a multikingdom microbial community called the root microbiota. Despite their importance for plant growth, the relationship between soil management, the root microbiota, and plant performance remains unknown. Here, we characterize the maize root-associated bacterial, fungal, and oomycetal communities during the vegetative and reproductive growth stages of four maize inbred lines and the ; phosphate transporter mutant.

Temperature-induced diurnal redox potential in soil.

With the capabilities to measure redox potentials () at a high temporal resolution, scientists have observed diurnal that occur in a distinct periodicity in soils and sediments. These patterns have been disregarded for a long time because minor fluctuations of the in the tens of mV range are difficult to interpret. Various explanations have been proposed for the origin of diel but a cohesive assessment of the temperature-dependency for field- and laboratory-based investigations is missing at present.

Full-scale accelerated carbonation of waste incinerator bottom ash under continuous-feed conditions.

Bottom ash (BA) is the dominant residue derived from the incineration of municipal solid waste or refuse-derived fuel (RDF). Costs for the disposal of the material chiefly depend on the leachability of salts and trace metals which may be cut by ageing the BA for several months to promote carbonation via uptake of carbon dioxide (CO). Enhanced exposure to CO sources has been referred to as accelerated carbonation.

Leaching of hexavalent chromium from young chromite ore processing residue.

Chromite ore processing residue (COPR) is a waste derived from the chromate extraction from roasted ores and is deposited in some countries in landfills. The objective of this study was to investigate the leaching characteristics of hexavalent Cr [Cr(VI)] from two COPR samples obtained from unlined landfills in the Kanpur area of northern India. Column experiments were conducted under water-saturated conditions to simulate Cr release from the wastes caused by tropical heavy-rain events.

Soil Organic Matter and Phosphate Sorption on Natural and Synthetic Fe Oxides under in Situ Conditions.

Iron (Fe) oxides in soils are strong sorbents for environmentally important compounds like soil organic matter (SOM) or phosphate, while sorption under field conditions is still poorly understood. We installed polyvinyl chloride plastic bars which have been coated either with synthetic Fe or manganese (Mn) oxides for 30 days in a redoximorphic soil. A previous study revealed the formation of newly formed ("natural") Fe oxides along the Mn oxide coatings.

Site-specific distribution of oak rhizosphere-associated oomycetes revealed by cytochrome c oxidase subunit II metabarcoding.

The phylum Oomycota comprises important tree pathogens like , involved in central European oak decline, and shown to affect holm oaks among many other hosts. Despite the importance to study the distribution, dispersal and niche partitioning of this phylum, metabarcoding surveys, and studies considering environmental factors that could explain oomycete community patterns are still rare. We investigated oomycetes in the rhizosphere of evergreen oaks in a Spanish oak woodland using metabarcoding based on Illumina sequencing of the taxonomic marker cytochrome c oxidase subunit II (cox2).

Continuous-feed carbonation of waste incinerator bottom ash in a rotating drum reactor.

Carbonation is a key process in the aging of waste incinerator bottom ash (BA). The reaction with CO decreases the BA alkalinity and lowers the leachability of amphoteric trace metals. Passive ageing over several months is usually performed in intermittently mixed BA heaps.

A fast and simple method to monitor carbonation of MSWI bottom ash under static and dynamic conditions.

Accelerated carbonation may be employed to improve the leaching behaviour and the geotechnical properties of MSWI bottom ash (BA). Here we report on a novel method to monitor and evaluate the progress of carbonation in both static and dynamic reactor systems. The method is based on following the pressure drop in the gas phase induced by the CO-uptake of BA and was benchmarked against carbonate contents as measured by thermogravimetry.

Sequential extraction of chromium, molybdenum, and vanadium in basic oxygen furnace slags.

Basic oxygen furnace slags (BOS) are by-products of basic oxygen steel production. Whereas the solubility of some elements from these slags has been well investigated, information about the mineralogy and related leaching, i.e.

Traffic-related distribution of antimony in roadside soils.

Vehicular emissions have become one of the main source of pollution of urban soils; this highlights the need for more detailed research on various traffic-related emissions and related distribution patterns. Since the banning of asbestos in the European Union, its substitution with antimony (Sb) in brake linings has led to increased inputs of this toxic metalloid to environmental compartments. The objective of this study was to provide detailed information about the spatial distribution patterns of Sb and to assess its mobility and bioavailability.

Environmental status of groundwater affected by chromite ore processing residue (COPR) dumpsites during pre-monsoon and monsoon seasons.

Chromite ore processing residue (COPR) is generated by the roasting of chromite ores for the extraction of chromium. Leaching of carcinogenic hexavalent chromium (Cr(VI)) from COPR dumpsites and contamination of groundwater is a key environmental risk. The objective of the study was to evaluate Cr(VI) contamination in groundwater in the vicinity of three COPR disposal sites in Uttar Pradesh, India, in the pre-monsoon and monsoon seasons.

Chromium Release from a COPR-Contaminated Soil at Varying Water Content and Redox Conditions.

Many soils in the region of Kanpur, North India, are heavily affected by the leather industry and its upstream supplier sector, as indicated by elevated chromium (Cr) contents. Under reducing conditions-for instance, at water saturation after monsoon rain or flood irrigation-the dynamic and species distribution of Cr may be affected due to changes in redox potential (E). In this study, the influence of E on the speciation and release of Cr from a contaminated agricultural soil was investigated.

Isotopic Fingerprints of Iron-Cyanide Complexes in the Environment.

Tracing the origin of iron-cyanide complexes in the environment is important because these compounds are potentially toxic. We determined the stable isotopic compositions of cyanide-carbon (CCN) and cyanide-nitrogen (NCN) in 127 contaminated solids and 11 samples of contaminated groundwater from coal carbonization sites, blast furnace operations, and commercial cyanide applications. Coal-carbonization-related cyanides had unique high mean δ(13)CCN values of -10.

Long-term ferrocyanide application via deicing salts promotes the establishment of Actinomycetales assimilating ferrocyanide-derived carbon in soil.

Cyanides are highly toxic and produced by various microorganisms as defence strategy or to increase their competitiveness. As degradation is the most efficient way of detoxification, some microbes developed the capability to use cyanides as carbon and nitrogen source. However, it is not clear if this potential also helps to lower cyanide concentrations in roadside soils where deicing salt application leads to significant inputs of ferrocyanide.

Chemical and mineralogical characterization of chromite ore processing residue from two recent Indian disposal sites.

Chromite ore processing residue (COPR) is a hazardous waste. Nevertheless, deposition of COPR in uncontrolled surface landfills is still common practice in some countries. Whereas old (between at least 40 and 180 years) COPR from the temperate zone has been intensively investigated, information on COPR in other regions is restricted.

Volatilization of elemental mercury from fresh blast furnace sludge mixed with basic oxygen furnace sludge under different temperatures.

Blast furnace sludge (BFS) is a waste with elevated mercury (Hg) content due to enrichment during the production process of pig iron. To investigate the volatilization potential of Hg, fresh samples of BFS mixed with basic oxygen furnace sludge (BOFS; a residue of gas purification from steel making, processed simultaneously in the cleaning devices of BFS and hence mixed with BFS) were studied in sealed column experiments at different temperatures (15, 25, and 35 °C) for four weeks (total Hg: 0.178 mg kg(-1)).

Sequential extraction of inorganic mercury in dumped blast furnace sludge.

Blast furnace sludge (BFS) is an industrial waste with elevated mercury (Hg) contents due to the enrichment during the production process of pig iron. To investigate the potential pollution status of dumped BFS, 14 samples with total Hg contents ranging from 3.91 to 20.

Manganese-oxide-coated redox bars as an indicator of reducing conditions in soils.

Identification of reducing conditions in soils is of concern not only for pedogenesis but also for nutrient and pollutant dynamics. We manufactured manganese (Mn)-oxide-coated polyvinyl chloride bars and proved their suitability for the identification of reducing soil conditions. Birnessite was synthesized and coated onto white polyvinyl chloride bars.

Release of Pharmaceuticals under Reducing Conditions in a Wastewater-Irrigated Mexican Soil.

Wastewater irrigation is often performed by flood irrigation, leading to changes in redox potential (Eh) of irrigated soils. In addition to soil organic matter, Fe-(hydr)oxides are important sorbents for pollutants, and biotransformation of pollutants can be accelerated under reducing conditions. Here, the influence of reducing conditions on the release of sorbed pharmaceuticals from soil and their potential accelerated dissipation was investigated in a microcosm study.

Mercury in dumped blast furnace sludge.

Blast furnace sludge (BFS) is a waste generated in the production of pig iron and was dumped in sedimentation ponds. Sixty-five samples from seven BFS locations in Europe were investigated regarding the toxic element mercury (Hg) for the first time. The charge material of the blast furnace operations revealed Hg contents from 0.

Arsenic mobility and speciation in a gleysol with petrogleyic properties: a field and laboratory approach.

Naturally elevated levels of As have been observed in some iron-enriched lowland soils of the southern Münsterland, Germany. To determine whether As is mobilized by the reductive dissolution of As-hosting Fe oxides at reducing soil conditions, the release of arsenate and arsenite was investigated in the field for 24 mo and in laboratory experiments. The grassland Gleysol consists of oximorphic soil horizons (Ah 0-15, Bg 15-35, CrBg 35-70 cm) developed from fluvial loam overlaying sand with reductomorphic properties (2Cr, +70 cm).

Speciation of Zn in blast furnace sludge from former sedimentation ponds using synchrotron X-ray diffraction, fluorescence, and absorption spectroscopy.

Blast furnace sludge (BFS), an industrial waste generated in pig iron production, typically contains high contents of iron and various trace metals of environmental concern, including Zn, Pb, and Cd. The chemical speciation of these metals in BFS is largely unknown. Here, we used a combination of synchrotron X-ray diffraction, micro-X-ray fluorescence, and X-ray absorption spectroscopy at the Zn K-edge for solid-phase Zn speciation in 12 BFS samples collected on a former BFS sedimentation pond site.

Optimized enrichment and purification of ferrocyanide for 13/12C and 15/14N isotope analysis of aqueous solutions.

The occurrence of ferrocyanide, Fe(CN)(6)(4-), in aqueous environments is of concern, since it is potentially hazardous. For tracing the source of ferrocyanide in contaminated water we developed a method that relies on the determination of the stable isotope ratios of (13)C/(12)C and (15)N/(14)N of this complexed cyanide (CN) after precipitating it as cupric ferrocyanide, Cu(2)[Fe(CN)(6)] · 7H(2)O. The precipitate was combusted and the isotope ratios were determined by continuous flow isotope ratio mass spectrometry.