Humic-like substances global levels and extraction methods in aerosols

Environmental Chemistry Letters - The abundance of humic-like substances in the atmosphere has received considerable attention since these substances play an important role in various atmospheric...     

A strategy for wildlife management in depopulating rural areas of Japan

Former ranges of wild animals have been reestablished in many developed countries. However, this reestablishment has led to increasing human–wildlife conflict in agroforest ecosystems. In Japan, human–wildlife conflict, such as crop raiding by and ecological impacts of wild ungulates and primates, is a serious problem in depopulated rural areas due to these animal range expansions and increased abundances. Japan's human population is predicted to decline by 24% by 2050, and approximately 20% of agricultural settlements will become completely depopulated. In this scenario, anthropogenic pressures on wildlife (e.g., hunting and habitat alteration) will continue to decrease and human–wildlife conflict will increase due to increasing wildlife recovery. Japan's local governments plan to slow range recovery, prevent species reestablishment, or remove recolonizing large mammals through lethal control. This strategy, however, is not cost-effective, and workforce shortages in depopulated communities make it infeasible. Moreover, the suppression of wildlife prevents the recovery of ecological functions and thus would degrade regional biodiversity. The declining pressure on wildlife that accompanies human depopulation will prevent the restoration of any past states of human–wildlife interaction. We suggest human-used areas in rural landscapes be aggregated in compact cities and that in transition zones between human settlements and depopulated lands that land-sharing approaches be applied. Concentrating management efforts in compact cities may effectively decrease human–wildlife conflict, rather than intensifying human pressures. Reforestation of depopulated lands may lead to recovery of wildlife habitats, their ecosystem functions, and regional biodiversity due to minimization of negative anthropogenic effects (land-sparing approach). Balancing resolution of human–wildlife conflict and ecological rewilding could become a new, challenging task for regional wildlife managers.     

Structural characterization and visible light activated photocatalytic ability of glass–ceramics prepared from municipal solid waste

Journal of Material Cycles and Waste Management - The relationship between local structure and visible-light-activated photocatalytic ability of glass–ceramics prepared from Municipal Solid...     

Airborne hydrophilic microplastics in cloud water at high altitudes and their role in cloud formation

Microplastic pollution is occurring in most ecosystem, yet their presence in high altitude clouds and their influence on cloud formation and climate change are poorly known. Here we analyzed microplastics in cloud water sampled at the summits of Japan mountains at 1300–3776 m altitude by attenuated total reflection imaging and micro-Fourier transform infrared spectroscopy. We observed nine microplastics including polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyamide 6, polycarbonate, ethylene–propylene copolymer or polyethylene–polypropylene alloy, polyurethane, and epoxy resin. Microplastic were fragmented, with mean concentrations ranging from 6.7 to 13.9 pieces per liter, and with Feret diameters ranging from 7.1 to 94.6 μm. Microplastics bearing hydrophilic groups such as carbonyl and/or hydroxyl groups were abundant, suggesting that they might have acted as condensation nuclei of cloud ice and water. Overall, our finding suggest that high-altitude microplastics cloud influence cloud formation and, in turn, might modify the climate.

     

Triterpenoid and caffeic acid derivatives in the leaves of ragweed, <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> L. (Asterales: Asteraceae), as feeding stimulants of <Emphasis Type="Italic">Ophraella communa</Emphasis> LeSage (Coleoptera: Chrysomelidae)

Summary. The leaf beetle Ophraella communa infests almost exclusively Ambrosia artemisiifolia in the fields of Japan, even though it normally feeds on several Asteraceous plants. A filter paper bioassay showed that the feeding of O. communa is strongly stimulated by methanolic extracts of A. artemisiifolia. The feeding stimulants for O. communa have been isolated from methanolic extracts of A. artemisiifolia. -Amyrin acetate, -amyrin acetate, 5-caffeoylquinic acid (chlorogenic acid) and 3,5-dicaffeoylquinic acid from A. artemisiifolia have been identified as feeding stimulants for O. communa. Triterpenoid derivatives (-amyrin acetate or -amyrin acetate) and caffeic acid derivatives (3, 5-dicaffoylquinic acid or 5-caffeoylquinic acid) showed feeding stimulant activity when mixed together.     

Effect of arsenic-contaminated irrigation water on agricultural land soil and plants in West Bengal, India

Total arsenic withdrawn by the four shallow tubewells, used for agricultural irrigation in the arsenic-affected areas of Murshidabad district per year is 6.79 kg (mean: 1.79 kg, range: 0.56-3.53 kg) and the mean arsenic deposition on land per year is 5.02 kg ha(-1) (range: 2-9.81 kg ha(-1)). Mean soil arsenic concentrations in surface, root of plants, below ground level (0-30 cm) and all the soils, collected from four agricultural lands are 14.2 mg/kg (range: 9.5-19.4 mg/kg, n = 99), 13.7 mg/kg (range: 7.56-20.7 mg/kg, n = 99), 14.8 mg/kg (range: 8.69-21 mg/kg, n = 102) and 14.2 mg/kg (range: 7.56-21 mg/kg, n = 300) respectively. Higher the arsenic in groundwater, higher the arsenic in agricultural land soil and plants has been observed. Mean arsenic concentrations in root, stem, leaf and all parts of plants are 996 ng/g (range: <0.04-4850 ng/g, n = 99), 297 ng/g (range: <0.04-2900 ng/g, n = 99), 246 ng/g (range: <0.04-1600 ng/g, n = 99) and 513 ng/g (range: <0.04-4850 ng/g, n = 297) respectively. Approximately 3.1-13.1, 0.54-4.08 and 0.36-3.45% of arsenic is taken up by the root, stem and leaf respectively, from the soil.     

Arsenic and other heavy metals in soils from an arsenic-affected area of West Bengal,India

Domkal is one of the 19, out of 26 blocks in Murshidabad district where groundwater contains arsenic above 0.05 mg/l. Many millions of cubic meters of groundwater along with arsenic and other heavy metals are coming out from both the hand tubewells, used by the villagers for their daily needs and shallow big diameter tubewells, installed for agricultural irrigation and depositing on soil throughout the year. So there is a possibility of soil contamination which can moreover affect the food chain, cultivated in this area. A somewhat detailed study was carried out, in both micro- and macrolevel, to get an idea about the magnitude of soil contamination in this area. The mean concentrations (mg/kg) of As (5.31), Fe (6740), Cu (18.3), Pb (10.4), Ni (18.8), Mn (342), Zn (44.3), Se (0.53), Mg (534), V (44.6), Cr (33.1), Cd (0.37), Sb (0.29) and Hg (0.54) in fallow land soils are within the normal range. The mean As (10.7), Fe (7860) and Mg (733) concentrations (mg/kg) are only in higher side whereas Hg (0.17 mg/kg) is in lower side in agricultural land soils, compared to the fallow land soils. Arsenic concentrations (11.5 and 28.0 mg/kg respectively) are high in those agricultural land soils where irrigated groundwater contains high arsenic (0.082 and 0.17 mg/l respectively). The total arsenic withdrawn and mean arsenic deposition per land by the 19 shallow tubewells per year are 43.9 kg (mean: 2.31 kg, range: 0.53-5.88 kg) and 8.04 kg ha(-1) (range: 1.66-16.8 kg ha(-1)) respectively. For the macrolevel study, soil arsenic concentration decreases with increase of distance from the source and higher the water arsenic concentration, higher the soil arsenic at any distance. A proper watershed management is urgently required to save the contamination.     

Research to develop a predicting system of mammalian subacute toxicity (3) construction of a predictive toxicokinetics model

A new predictive toxicokinetics model was developed to estimate subacute toxicity (target organs, severity, etc.) of non-congeneric industrial chemicals, where the chemical structures and physico-chemical properties are only available. Thus, a physiological pharmacokinetics model, which consists of blood, liver, kidney (these were experimentally found as major toxicological targets), muscle and fat compartments , was established to simulate the chemical concentrations in organs/tissues with pharmacokinetic parameters by means of Runge-Kutta-Gill algorithm. The pliarmacokinetic parameters, i.e. absorption rate, absorption ratio, hepatic extraction ratio of metabolism and renal clearance were calculated by using separately established Quantitative Structure-Pharmacokinetics Relationship equations. The developed predictive model was then applied to simulations of 43 non-congeneric industrial chemicals. The chemical concentrations in organs/tissues after single oral administration were simulated, and their maximum concentrations (Cmax's) and area tinder the concentration-time curves (AUC's) were calculated.Fast Inverse Laplace Transform was newly applied for the purpose of simulation of 28-day repeated dose toxicity.Simulated concentrations of 28 days repeated dose were, however, found to be the same as those of simple repetitions of a single administration per day because of the short half-lives of non-congeneric industrial chemicals.A comparison of subacute toxicity data with Cmax's and AUC's in a single dose scenario suggested that the organs/tissues with relatively high concentrations of tested chemical substances were the most sensitive targets within a chemical.Chemical concentrations in liver, for instance, were correlated with the severity of hepatotoxicity among the chemicals. It was also suggested that to improve and widen the present approach, data of metabolite and reactivity of non-congeneric industrial chemicals to organs/tissues, receptors, etc. should be incorporated into the model.     

Effect of silica sand on activation energy for diffusion of sodium ions in montmorillonite and silica sand mixture

The effect of silica sand on the diffusion of sodium ions in mixtures of montmorillonite and silica sand was studied by measuring the apparent diffusion coefficients, activation energies for diffusion, and the basal spacing of the mixed samples. These diffusion experiments suggest that the apparent diffusion coefficients of sodium ions in the mixed samples were almost the same as those of pure montmorillonite samples having the same partial dry densities of montmorillonite. The activation energy dependence for diffusion of sodium ions on the partial dry density was different between the mixed samples and the pure montmorillonite samples. The activation energy increased by adding silica sand at the partial dry density of 1.0 Mg m(-3), and decreased by adding silica sand at the partial dry densities higher than 1.2 Mg m(-3). A change in the XRD profile was observed after adding silica sand at the partial dry density of 1.6 Mg m(-3). Here, a three-water-layer hydrate state of montmorillonite was found in the mixed sample whereas only a two-water-layer hydrate state was observed in the pure montmorillonite sample. These experimental results suggest that silica sand changed the montmorillonite microstructure in the mixed samples, which then altered the sodium-ion diffusion process.     

Isomer distribution of nitrotriphenylenes in airborne particles, diesel exhaust particles, and the products of gas-phase radical-initiated nitration of triphenylene

The formation of mutagenic nitro-polycyclic aromatic hydrocarbons (NPAHs) 1- and 2-nitrotriphenylene (1- and 2-NTP) via gas-phase OH or NO₃ radical-initiated reactions of triphenylene was demonstrated for the first time using a flow reaction system. In contrast with the results of conventional electrophilic nitration, 2-NTP was formed in larger yield than 1-NTP, but this is consistent with the mechanism proposed for gas-phase radical-initiated nitration of PAH. In diesel exhaust particle (DEP) samples, both 1- and 2-NTP were identified and their concentrations determined, as well as 1-nitropyrene (1-NP), which is a representative combustion-derived NPAH: the mean concentrations of 1-NTP, 2-NTP, and 1-NP were 4.7, 1.9, and 32 pmol mg_DEP^–1, respectively. The mean 2-NTP/1-NTP, 1-NTP/1-NP, and 2-NTP/1-NP ratios in samples of airborne particles collected in a residential area in Osaka, Japan, were>1.55,<0.25, and 0.37, respectively; these values are much higher than those of the DEP samples. This finding indicates that there is another source for airborne NTPs, especially 2-NTP, apart from diesel exhaust. These results strongly suggest that airborne NTPs originate from atmospheric processes such as radical-initiated reactions of triphenylene, and this has a significant influence on the atmospheric occurrence of NTPs.