Magnetic activated carbon from spent coffee grounds: iron-catalyzed CO2 activation mechanism and adsorption of antibiotic lomefloxacin from aqueous medium.

The facile fabrication of low-cost adsorbents possessing high removal efficiency and convenient separation property is an urgent need for water treatment. Herein, magnetic activated carbon was synthesized from spent coffee grounds (SCG) by Fe-catalyzed CO2 activation at 800 °C for 90 min, and magnetization and pore formation were simultaneously achieved during heat treatment. The sample was characterized by N2 adsorption-desorption, XRD, VSM, SEM, and FTIR. Batch adsorption experiments were conducted using lomefloxacin (LMO) as the probing pollutant. Preparation mechanism was revealed by TG-FTIR and XRD. Experimental results showed that Fe3O4 derived from Fe species can be reduced to Fe by carbon at high temperatures, followed by subsequent reoxidation to Fe3O4 by CO2, and the redox cycle between Fe and Fe3O4 favored the formation of pores. The promotion effects of Fe species on CO2 activation can be quantitatively reflected by the yield of CO as the signature gaseous product, and the suitable activation temperate range was determined to be 675 to 985 °C. The BET surface area, total pore volume, and saturated magnetization value of the product were 586 m2 g-1, 0.327 cm3 g-1, and 11.59 emu g-1, respectively. The Langmuir model was applicable for the adsorption isotherm data for LMO with the maximum adsorption capacity of 95 mg g-1, and thermodynamic analysis revealed that the adsorption process was endothermic and spontaneous. This study demonstrated that Fe-catalyzed CO2 activation was an effective method of converting SCG into magnetic separable adsorbent for LMO removal from aqueous medium.

Short-term impact of different doses of spent coffee grounds, salt, and sand on soil chemical and hydrological properties in an urban soil.

Natural and human activities have deteriorated urban soil's health and ecological functions as compared to forest soils. Therefore, we hypothesized that any intervention in poor quality soil in urban area will change their chemical and water retention properties. The experiment was conducted in Krakow (Poland) in completely randomized design (CRD). The soil amendments used in this experiment consisted of control, spent coffee grounds (SCGs), salt, and sand (1 and 2 t ha-1) in order to evaluate the impact of these soil amendments on the urban soil chemical and hydrological properties. Soil samples were collected after 3 months of soil application. The soil pH, soil acidity (me/100 g), electrical conductivity (mS/cm), total carbon (%), CO2 emission (g m-2 day-1), and total nitrogen (%) were measured in laboratory condition. The soil hydrological properties like volumetric water content (VWC), water drop penetration time (WDPT), current water storage capacity (Sa), water storage capacity after 4 and 24 h (S4 and S24), and capillary water Pk (mm) were also determined. We noted variations in soil chemical and water retention properties in urban soil after the application of SCGs, sand, and salt. It was observed that SCGs (2 t ha-1) has reduced soil pH and nitrogen (%) by 14 and 9%, while the incorporation of salt resulted in maximum soil EC, total acidity, and soil pH. The soil carbon (%) and CO2 emission (g m-2 day-1) were enhanced and declined by SCGs amendment. Furthermore, the soil hydrological properties were significantly influenced by the soil amendment (spent coffee grounds, salt, and sand) application. Our results showed that spent coffee grounds mixing in urban soil has considerably enhanced the soil VWC, Sa, S4, S24, and Pk, whereas it decreased the water drop penetration time. The analysis showed that the single dose of soil amendments had not improved soil chemical properties very well. Therefore, it is suggested that SCGs should be applied more than single dose. This is a good direction to look for ways to improve the retention properties of urban soil and you can consider combining SCGs with other organic materials like compost, farmyard manure, or biochar.

Inhalation risk to PAHs and BTEX during barbecuing: The role of fuel/food type and route of exposure.

The manuscript presents an innovative and holistic approach to quantifying PAHs and BTEX emissions from the grilling process and indicates a novel driven-toxicity-based solution to recognize health effects related to BBQ emissions. The exposure scenario includes the type of grilling device, food type, and individual attitudes, but also a keen understanding of the broad health implications related to the gaseous/particulate PAHs emission, or age-related effects. The calculated incremental lifetime cancer risk (ILCR) associated with the exposure to PAH congeners and BTEX indicates an unacceptable level in the case of charcoal and briquette grilling with the highest values for professional cooks. The sum of 15 PAH concentrations in grilled foods was highest for meat grilling over charcoal briquettes - 382,020.39 ng/m3 and lowest for meat grilling on a gas grill - 1442.16 ng/m3. The emissions of BTEX from lump charcoal grilling were 130 times higher compared to the gaseous grill. In all considered scenarios lump-charcoal and charcoal briquettes grilling derive the ILCR above the 10-4, indicating negative effects of traditional grills on human health. The paper completes knowledge of wide-ranging health implications associated with BBQs, a topic that is almost completely unaddressed among the scientific community and policymakers.

Ultra-high adsorption of Hg0 using impregnated activated carbon by selenium.

Activated carbon was one of the main adsorptions utilized in elemental mercury (Hg0) removal from coal combustion flue gas. However, the high cost and low physical adsorption efficiency of activated carbon injection (ACI) limited its application. In this study, an ultra-high efficiency (nearly 100%) catalyst sorbent-Sex/Activated carbon (Sex/AC) was synthesized and applied to remove Hg0 in the simulated flue gas, which exhibited 120 times outstanding adsorption performance versus the conventional activated carbon. The Sex/AC reached 17.98 mg/g Hg0 adsorption capacity at 160 °C under the pure nitrogen atmosphere. Moreover, it maintained an excellent mercury adsorption tolerance, reaching the efficiency of Hg0 removal above 85% at the NO and SO2 conditions in a bench-scale fixed-bed reactor. Characterized by the multiple methods, including BET, XRD, XPS, kinetic and thermodynamic analysis, and the DFT calculation, we demonstrated that the ultrahigh mercury removal performance originated from the activated Se species in Sex/AC. Chemical adsorption plays a dominant role in Hg0 removal: Selenium anchored on the surface of AC would capture Hg0 in the flue gas to form an extremely stable substance-HgSe, avoiding subsequent Hg0 released. Additionally, the oxygen-containing functional groups in AC and the higher BET areas promote the conversion of Hg0 to HgO. This work provided a novel and highly efficient carbon-based sorbent -Sex/AC to capture the mercury in coal combustion flue gas. Graphical abstract Selenium-modified porous activated carbon and the interface functional group promotes the synergistic effect of physical adsorption and chemical adsorption to promote the adsorption capacity of Hg0.

[Detection of Residual Solvents in Commercial Supplements Using Headspace (HS)-GC-MS].

In order to understand the actual state of residual solvents contained in commercial supplements, we performed a simultaneous analysis of residual solvents by headspace (HS)-GC-MS with reference to the Japanese Pharmacopoeia's "Residual Solvents", for 29 products selected from among commercial supplements (e.g., revitalizers, weight loss pills) that are deeply colored or contain coating agents and extract powder. As a result, benzene (class 1) was detected in eight black-colored supplements, and hexane (class 2B) was also detected in one of those products. On the other hand, methanol (class 2A) was detected in four products containing coating agents and extract powders, such as citrus peel extract. None of these residual solvents exceeded the concentration limits set by the Japanese Pharmacopoeia. Benzene was detected at 1.7 µg/g, which was near the concentration limit, in some products. As raw materials used for the manufacture of the black-colored supplements from which benzene was detected commonly included activated carbon, we analyzed the residual solvents contained in activated carbon commercially available for use as food additive and in food production and medicine. As a result, benzene was detected at high concentrations in activated carbon made from hemp (approximately 29 µg/g) and bamboo (approximately 140 µg/g).

Influences of arbuscular mycorrhizae, phosphorus fertiliser and biochar on alfalfa growth, nutrient status and cadmium uptake.

The objective of the study was to explore the influences of arbuscular mycorrhizae (AM), phosphorus (P) fertiliser, biochar application (BC) and their interactions on Medicago sativa growth, nutrient, Cd content and AM fungi-plant symbioses. Applications of both P fertiliser and BC significantly increased total biomass and P and potassium (K) uptake, regardless of AM. When no P fertiliser or BC was used, the shoot biomass and nitrogen (N), P, and K contents in the +AM treatments were 1.39, 1.54, 4.53 and 2.06 times higher than those in the -AM treatments, respectively. AM fungi only elevated the total P uptake by 44.03% when P fertiliser was applied at a rate of 30 mg P kg-1 in the absence of BC addition. With BC application or high-P fertiliser input (100 mg P kg-1), the soil available P was significantly higher than that in the other treatments, and AM fungi significantly reduced the shoot biomass. The minimum Cd concentration occurred in the shoots of alfalfas treated with BC and high-P fertiliser inputs; this concentration was lower than the maximum permitted concentration in China. Although the BC and high-P inputs could eliminate the positive mycorrhizal response, the results suggested that BC application in combination with high-P fertiliser input could not only increase forage yields but also lower Cd concentrations to meet the forage safety standards by the dilution effect.

Inventory of main greenhouse gas emissions from energy sector in Palestine.

This paper analyzes the building process of the main greenhouse gas (GHG) emissions (CO2, CH4 and N2O) inventory from the energy sector in Palestine. The paper includes determination tools, i.e., emission factors, to estimate the amounts of national GHG emissions from sub-sectors of energy including energy industries, manufacturing industries and construction, transport and other sectors (households, agriculture and commerce and public services). The results show that the total amount of national GHG emissions from the energy sector in 2016 was 4131 thousand metric tons of CO2-equivalent (TtCO2e), which represented 0.011% of the total global GHG emissions. The average value of GHG emissions per capita from the energy sector was 0.86 tCO2e in Palestine, and its gross domestic product was estimated at 3212 $/ton of CO2e. The estimated amounts of CO2, CH4 and N2O emission from the energy sector were 4022, 49 and 60 TtCO2e, respectively. The transport and household sub-sectors dominated the national GHG emissions from the entire energy sector by 58 and 32%, respectively. In general, fuels including diesel, gasoline, wood and charcoal and liquefied petroleum gas made most of the total amount of the national GHG emissions from the energy sector at 50, 18, 18 and 12%, respectively. Finally, the mitigation actions included in the first nationally determined contribution of Palestine and recommendations to help lower the national GHG emissions from the Palestinian energy sector are provided.

Synthesis of enriched biochar as a vehicle for phosphorus in tropical soils

Phosphorus (P) is one of the nutrients that most limits agricultural productivity, especially in tropical soils. Enriched biochar has been proposed to increase the bioavailability of P and other nutrients in the soil. Thus, the objective of this study was to evaluate the availability of P in phosphate biochar (composed of biomass and soil) as a function of the triple superphosphate mixture before and after the pyrolysis process. We produced eight types of enriched biochar via pyrolysis by combining sandy or clayey soil with rice or coffee husk, and by adding triple superphosphate before or after pyrolysis. The heating of the phosphate fertilizer during the pyrolysis process resulted in a higher crystallinity of the phosphates, lower content of labile fractions of P and lower content of available P in phosphate biochars than when the superphosphate was added after pyrolysis. (AU)

Driving forces and barriers in the removal of phosphorus from water using crop residue, wood and sewage sludge derived biochars.

The removal of phosphorus (P) from sewage effluents is necessary to control eutrophication in receiving waters. Biochar has been proposed and is investigated for the capture and reuse of P, however the forces driving and limiting P adsorption are still largely unclear. To identify the forces governing P uptake by biochar, biochars with markedly different physicochemical characteristics derived from a variety of biomass (oilseed rape straw, wheat straw, miscanthus straw, rice husk, soft wood and sewage sludge residue), pyrolysed at various temperatures, were investigated. The biochar samples were characterised in terms of pH, electrical conductivity, total acidity, carbon chemistry, metal composition, surface area, and porosity, and the uptake and release of P was compared to the biochar properties using multivariate analysis. Uptake of P by the biochars as such was low (< 0.71 mg P/g biochar with feed solutions of 50 mg P/l) and, among the variables studied, the biochars' Ca and Mg content was key in P removal and found to be pH dependant. Enhancement of biochar surface area and porosity was carried out by activation with CO2 at 800 °C and the uptake significantly improved (p < 0.05) (i.e. an increased surface area from <20 m2/g up to 781 m2/g gave a limited improvement in P removal to <1.2 mg P/g biochar at feed level of 50 mg P/l). These results confirm that the potential to use these unmodified biochars derived from a variety of biomass for P sorption is low, but that the material provides properties that may be modified or enhanced to increase sorption capacity. This study indicates that biochar/biochar feedstock with greater content of Ca and Mg will be more advantageous for P capture.

Interactive effects of rice straw biochar and γ-Al2O3 on immobilization of Zn.

Biochar system technology has been proved as a sustainable remediation method for metal contaminated soils. However, little attention has been paid to the interaction between biochar and oxide minerals and their influence on metal immobilization in soils. In this study, batch-type Zn sorption experiments were conducted using the mixture of γ-Al2O3 and rice straw biochar as a model binary geosorbent systems. In addition, advanced spectroscopic technics such as EXAFS, FTIR and XRD were performed to reveal the mechanism. EXAFS spectroscopy revealed that 62% of Zn existed as Zn-Al layered double hydroxide (LDH) on γ-Al2O3 at pH 7.5 (for 2 mM Zn loading) within 24 h, which was 19% in the mixture. The Zn in biochar samples mainly existed as Zn-OM (53%-76%) and Zn2SiO4 (21%-47%), while the proportion of Zn2SiO4 (0-6%) was negligible compared with Zn-Al silicate (26-48%) in the mixtures. The overall findings confirmed that Al released from γ-Al2O3 was sorbed in parallel with Zn on biochar to form Zn-Al silicate, rather than Zn-Al LDH on the γ-Al2O3 surface. These results unveiled the dynamic interactions between amended biochar and soil oxide minerals which can significantly affect the immobilization pathways of metals in contaminated soils.

Biochar additions alter phosphorus and nitrogen availability in agricultural ecosystems: A meta-analysis.

Biochar is a carbon (C) rich product of thermochemical conversion of organic material that is used as a soil amendment due to its resistance to decomposition and its influence on nutrient dynamics; however, individual studies on biochar effects on phosphorus (P) and nitrogen (N) have proven inconsistent. Herein, we performed a meta-analysis of 124 published studies to evaluate the influence of biochar on available P, microbial biomass P (MBP), and inorganic N (NO3--N and NH4+-N) in global agricultural ecosystems. Overall, the results showed that biochar applications significantly increased surface soil available P by 45% and MBP by 48% across the full range of biochar characteristics, soil type, or experimental conditions. By contrast, biochar addition to soil reduced NO3--N concentrations by 12% and NH4+-N by 11%, but in most cases biochar added in combination with organic fertilizer significantly increased soil NH4+-N compared to controls. Biochar C:N ratio and biochar source (feedstock) strongly influenced soil P availability response to biochar where inorganic N was most influenced by biochar C:N ratio and soil pH. Biochar made from manure or other low C:N ratio materials, generated at low temperatures, or applied at high rates were generally more effective at enhancing soil available P. It is important, however, to note that most negative results were observed in short-term (<6 months) where long-term studies (>12 months) tended to result in neutral to modest positive effects on both P and N. This meta-analysis indicates that biochar generally enhances soil P availability when added to soils alone or in combination with fertilizer. These findings provide a scientific basis for developing more rational strategies toward widespread adoption of biochar as a soil amendment for agricultural P and N management.

Nanocompósitos magnéticos para concentração/remoção de contaminantes de águas / Magnetic adsorbent nanocomposites for water treatment

Zeólitas e carvão ativado são materiais eficazes para o tratamento de efluentes devido a sua grande área superficial e possibilidades de funcionalização, que permitem o desenvolvimento de novos materiais derivados visando a processos de concentração/remoção de contaminantes, por exemplo, em águas. A preparação de nanocompósitos magnéticos e sua aplicação na remoção seletiva de poluentes em meio aquoso tornou-se viável devido as interações distintas que ocorrem entre zeólita e carvão ativado com compostos orgânicos, íons metálicos e compostos nitrogenados. Assim, novos materiais voltados para sistemas de tratamento de águas residuais e monitoramento ambiental foram desenvolvidos com base em materiais bem estabelecidos. Os nanocompósitos foram caracterizados estrutural e morfologicamente por técnicas de microscopia eletrônica de varredura, termogravimetria, espectroscopia no infravermelho, espalhamento de luz, difração de raios x, bem como suas capacidades de adsorção. Foi avaliado também a viabilidade de aplicações em métodos analíticos, como pré-concentração por extração em fase sólida magnética (M-SPE), e, para tratamento de efluentes em amostras reais. Contaminação por cromo (VI), outras espécies potencialmente tóxicas e amônio foram removidos de águas residuais, gerando produtos tratados com níveis de contaminantes suficientemente baixos para atenderem as recomendações da EPA (Environmental Protection Agency) e CONAMA (Conselho Nacional do Meio Ambiente), permitindo seu descarte na natureza. Os materiais demonstraram ser adequados para pré-concentração rápida, eficiente, economicamente competitiva e ambientalmente amigável de amostras por M-SPE para quantificação analítica de espécies orgânicas ou inorgânicas, por técnicas analíticas convencionais. Assim, foi demonstrado a possibilidade de determinação simultânea de elementos potencialmente tóxicos e de outros cátions metálicos em concentrações traço (ppb), diretamente no material compósito magnético, por espectroscopia de fluorescência de raios X de energia dispersiva (EDX), além da quantificação de traços de compostos orgânicos semi-voláteis por cromatografia emfase gasosa com detector por espectrometria de massas, aumentando a sensibilidade para além do limite nominal de detecção por essas técnicas

Zeolites and activated carbon are effective materials for the treatment of effluents due to their large surface area and functionalisation possibilities, which allow the development of new derived materials aiming at the concentration/removal of contaminants from water, for example. The preparation of magnetic nanocomposites and their application in the selective removal of pollutants in aqueous media has become feasible due to the distinct interactions that occur between zeolite and activated carbon with organic compounds, metal ions and nitrogen compounds. Thus, new materials for wastewater treatment and environmental monitoring systems were developed based on well-established materials. The nanocomposites were structural and morphologically characterized by scanning electron microscopy, thermogravimetry, infrared spectroscopy, light scattering, x-ray diffraction, as well as their adsorption capacities, viability of applications in analytical methods such as preconcentration by extraction in magnetic solid phase, M-SPE, were evaluated, and the composite materials Cmag and Zmag applied for treatment of real samples. Chromium (VI) contamination, heavy metal cations and ammonium were removed from wastewater, generating treated products with levels of contaminants low enough to meet the EPA and CONAMA recommendations, allowing their disposal in the wild. The materials have been shown to be suitable for rapid, efficient, economically competitive and environmentally friendly preconcentration of samples per M-SPE for analytical quantification of organic or inorganic species by conventional analytical techniques. Thus, it was demonstrated the possibility of simultaneous analysis of heavy metals and other metal cations in trace concentrations (ppb), directly in the magnetic composite material, by dispersive energy X-ray fluorescence spectroscopy (EDX), in addition to the quantification of traces of volatile organic compounds (VOC) by gas chromatography with mass spectrometry detector, increasing the sensitivity beyond the nominal limit of detection by these techniques

Preparation and characterisation of activated carbon from waste tea by physical activation using steam.

In this study, the feasibility of preparing activated carbon from waste tea by physical activation using steam was investigated. The effects of activation temperature on yield and pore properties of the prepared activated carbon were studied. The yield decreased with increased activation temperature owing to the decomposition of cellulose and hemicellulose. The specific surface area and pore volume of the activated carbon were estimated using the Brunauer-Emmett-Teller method, Langmuir equation, and t-plot method. The specific surface area and micropore volume increased with increases in activation temperature, as additional volatile materials were released. The specific surface area significantly decreased at first but slightly increased with increasing activation time. The maximum specific surface area reached 995 m2/g at an activation temperature of 800 °C with a water flow rate of 0.075 g/min and a constant hold time of 0.5 hr. According to the nitrogen adsorption isotherms, micropores mainly developed when the activation temperature was below 800 °C, and both micropores and mesopores developed when it was above 800 °C. The results showed that activation temperature significantly affected micropore and mesopore volumes, as well as the specific surface area of the activated carbon. Overall, waste tea was found to be an attractive raw material for producing low-cost activated carbon. Implications: Every year, a large amount of waste tea is generated after extraction. The high carbon content of waste tea showed that it can be used as raw material to produce activated carbon. This study investigated the feasibility of preparing activated carbon from waste tea by physical activation using steam. Temperature and time were found to have clear effects on pore properties. Our proposed method and raw material are more environmentally friendly and involve low cost. Furthermore, this offers a potential solution to the problems of waste tea disposal and low-cost activated carbon production.

Influence of biochar aged in acidic soil on ecosystem engineers and two tropical agricultural plants.

Biochar amendment to soil is predicted globally as a means to enhance soil health. Alongside the beneficial result on soil nutrient availability and retention, biochar is presumed to increase soil macro / microbiota composition and improve plant growth. However, evidence for such an effect remains elusive in many tropical agricultural soils. The influence of biochar aged in soil was assessed on soil microbiota, macrobiota (Eudrilus eugeniae), seedling emergence and early plant growth of Oryza sativa and Solanum lycopersicum in tropical agricultural soil, over a 90 d biochar-soil contact time. Results showed negative impacts of increased loading of biochar on the survival and growth of E. eugeniae. LC50 and EC50 values ranged from 34.8% to 86.8% and 0.9-23.7% dry biochar kg-1 soil, over time. The growth of the exposed earthworms was strongly reduced (R2 = -0.866, p < 0.05). Biochar significantly increased microbiota abundance relative to the control soil (p < 0.001). However, fungal population was reduced by biochar addition. Biochar application threshold of 10% and 5% was observed for (O. sativa) and (S. lycopersicum), respectively. Furthermore, the addition of biochar to soil resulted in increased aboveground (shoot) biomass (p < 0.01). However, the data revealed that biochar did not increase the belowground (root) biomass of the plant species during the 90 d biochar-soil contact time. The shoot-to-root-biomass increase indicates a direct toxic influence of biochar on plant roots. This reveals that nutrient availability is not the only mechanism involved in biota-biochar interactions. Detailed studies on specific biota-plant-responses to biochars between tropical, temperate and boreal environments are needed to resolve the large variations and mechanisms behind these effects.

Cooking fuel and risk of under-five mortality in 23 Sub-Saharan African countries: a population-based study.

Relationship between cooking fuel and under-five mortality has not been adequately established in Sub-Saharan Africa (SSA). We therefore investigated the association between cooking fuel and risk of under-five mortality in SSA, and further investigated its interaction with smoking. Using the most recent Demographic Health Survey data of 23 SSA countries (n = 783,691), Cox proportional hazard was employed to determine the association between cooking fuel and risk of under-five deaths. The adjusted hazard ratios were 1.21 (95 % CI, 1.10-1.34) and 1.20 (95 % CI, 1.08-1.32) for charcoal and biomass cooking fuel, respectively, compared to clean fuels. There was no positive interaction between biomass cooking fuel and smoking. Use of charcoal and biomass were associated with the risk of under-five mortality in SSA. Disseminating public health information on health risks of cooking fuel and development of relevant public health policies are likely to have a positive impact on a child's survival.

Comparison of phosphorus recovery from incinerated sewage sludge ash (ISSA) and pyrolysed sewage sludge char (PSSC).

This research compares and contrasts the physical and chemical characteristics of incinerator sewage sludge ash (ISSA) and pyrolysis sewage sludge char (PSSC) for the purposes of recovering phosphorus as a P-rich fertiliser. Interest in P recovery from PSSC is likely to increase as pyrolysis is becoming viewed as a more economical method of sewage sludge thermal treatment compared to incineration. The P contents of ISSA and PSSC are 7.2-7.5% and 5.6%, respectively. Relative to the sludge, P concentrations are increased about 8-fold in ISSA, compared to roughly 3-fold in PSSC. Both PSSC and ISSA contain whitlockite, an unusual form of calcium phosphate, with PSSC containing more whitlockite than ISSA. Acid leaching experiments indicate that a liquid/solid ratio of 10 with 30min contact time is optimal to release PO4-P into leachate for both ISSA and PSSC. The proportion of P extracted from PSSC is higher due to its higher whitlockite content. Heavy metals are less soluble from PSSC because they are more strongly incorporated in the particles. The results suggest there is potential for the development of a process to recover P from PSSC.

Charcoal production in the Mopane woodlands of Mozambique: what are the trade-offs with other ecosystem services?

African woodlands form a major part of the tropical grassy biome and support the livelihoods of millions of rural and urban people. Charcoal production in particular is a major economic activity, but its impact on other ecosystem services is little studied. To address this, our study collected biophysical and social datasets, which were combined in ecological production functions, to assess ecosystem service provision and its change under different charcoal production scenarios in Gaza Province, southern Mozambique. We found that villages with longer histories of charcoal production had experienced declines in wood suitable for charcoal, firewood and construction, and tended to have lower perceived availabilities of these services. Scenarios of future charcoal impacts indicated that firewood and woody construction services were likely to trade-off with charcoal production. However, even under the most extreme charcoal scenario, these services were not completely lost. Other provisioning services, such as wild food, medicinal plants and grass, were largely unaffected by charcoal production. To reduce the future impacts of charcoal production, producers must avoid increased intensification of charcoal extraction by avoiding the expansion of species and sizes of trees used for charcoal production. This is a major challenge to land managers and policymakers in the area.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'.

Karrikins Identified in Biochars Indicate Post-Fire Chemical Cues Can Influence Community Diversity and Plant Development.

BACKGROUND: Karrikins are smoke-derived compounds that provide strong chemical cues to stimulate seed germination and seedling growth. The recent discovery in Arabidopsis that the karrikin perception system may be present throughout angiosperms implies a fundamental plant function. Here, we identify the most potent karrikin, karrikinolide (KAR1), in biochars and determine its role in species unique plant responses. METHODS: Biochars were prepared by three distinct commercial-scale pyrolysis technologies using systematically selected source material and their chemical properties, including karrikinolide, were quantified. Dose-response assays determined the effects of biochar on seed germination for two model species that require karrikinolide to break dormancy (Solanum orbiculatum, Brassica tourneforttii) and on seedling growth using two species that display plasticity to karrikins, biochar and phytotoxins (Lactuca sativa, Lycopersicon esculentum). Multivariate analysis examined relationships between biochar properties and the plant phenotype. FINDINGS AND CONCLUSIONS: Results showed that karrikin abundant biochars stimulated dormant seed germination and seedling growth via mechanisms analogous to post-fire chemical cues. The individual species response was associated with its sensitivity to karrikinolide and inhibitory compounds within the biochars. These findings are critical for understanding why biochar influences community composition and plant physiology uniquely for different species and reaffirms that future pyrolysis technologies promise by-products that concomitantly sequester carbon and enhance plant growth for ecological and broader plant related applications.

2000 Years of Grazing History and the Making of the Cretan Mountain Landscape, Greece.

Understanding the processes that led to the recent evolution of Mediterranean landscapes is a challenging question that can be addressed with paleoecological data. Located in the White Mountains of Crete, Asi Gonia peat bog constitutes an exceptional 2000-years-long sedimentary archive of environmental change. In this study, we document the making of the White Mountains landscape and assess human impact on ecosystem trajectories. The paleoenvironmental reconstruction is based on high-resolution analyses of sediment, pollen, dung fungal spores and charcoal obtained from a 6-m core collected from the bog. Multiproxy analyses and a robust chronological control have shed light on anthropogenic and natural processes that have driven ecological changes, giving rise to the present-day Mediterranean ecosystem. Our results suggest that sediment accumulation began during the transition from the Hellenistic to the Roman period, likely due to watershed management. The evolution of the peat bog as well as vegetation dynamics in the surrounding area were linked to past climate changes but were driven by human activities, among which breeding was of great importance. Charcoal analysis reveals that fire was largely used for the construction and maintenance of sylvo-agropastoral areas. Pollen data allow the identification of three main vegetation assemblages: 1) evergreen oak forest (before ca. 850 AD), 2) heather maquis (ca. 850 to 1870 AD), 3) phrygana/steppe landscape. Rapid changes between phases in vegetation development are associated with tipping-points in ecosystem dynamics resulting from anthropogenic impact. The modern ecosystem did not get established until the 20th century, and it is characterized by biodiversity loss along with a dramatic drying of the peat bog.

Phosphorus reclamation through hydrothermal carbonization of animal manures.

Projected shortages of global phosphate have prompted investigation of methods that could be employed to capture and recycle phosphate, rather than continue to allow the resource to be essentially irreversibly lost through dilution in surface waters. Hydrothermal carbonization of animal manures from large farms was investigated as a scenario for the reclamation of phosphate for agricultural use and mitigation of the negative environmental impact of phosphate pollution. Hydrothermal reaction conditions were identified for poultry, swine, and cattle manures that resulted in hydrochar yields of 50-60% for all three manures, and >90% of the total phosphorus present in these systems was contained in the hydrochars as precipitated phosphate salts. Phosphate recovery was achieved in yields of 80-90% by subsequent acid treatment of the hydrochars, addition of base to acid extracts to achieve a pH of 9, and filtration of principally calcium phosphate. Phosphate recovery was achieved in yields of 81-87% based on starting manures by subsequent acid treatment of the hydrochars, addition of base to acid extracts to achieve a pH of 9, and filtration of principally calcium phosphate. Swine and cattle manures produced hydrochars with combustion energy contents comparable to those of high-end sub-bituminous coals.