Studies on automated survey system of environmental chemicals by gas chromatography-mass spectrometry-computer III. Construction of an automated survey system and its application

An automated survey system on the chemicals in environments by a gas chromatography-mass spectrometry-computer system has been constructed of Three Dimensional Mass Chromatography, Modified Probability Based Matching method, and Self Training Interpretive and Retrieval method. And it was applied to analyze environmental materials, with interesting results.     

Studies on automated survey system of environmental chemicals by gas chromatography-mass spectrometry-computer I. Retrieval system of mass spectra

A retrieval system of mass spectra based upon the Probability Based Matching method was studied in order to apply it to survey the chemicals in environments by a gas chromatography-mass spectrometry-computer system. As retrieval indices, peak missing probability and relative confidence value were proposed.     

The influence of forest fires on CO, HCN, C2H6, and C2H2 over northern Japan measured by infrared solar spectroscopy

Total column abundances of CO, HCN, C₂H₆, and C₂H₂ have been retrieved from infrared solar spectra observed at Moshiri (44.4°N) and Rikubetsu (43.5°N) in northern Japan from 1997 to 2005. The spectra were recorded with high spectral resolution ground-based Fourier transform infrared (FTIR) spectrometers and total column abundances were calculated by SFIT1 version 1.09e. Deviations of these species relative to their seasonal mean values (ΔCO, ΔHCN, ΔC₂H₆, and ΔC₂H₂) were derived, which showed short-time enhancements in 1998, 2002, and 2003. Good correlations among ΔCO, ΔHCN, ΔC₂H₆, and ΔC₂H₂ in a few months of each year were seen. Since the number of forest fires in Siberia had large enhancements in 1998, 2002, and 2003, trajectory analyses were performed in order to assess the influence of forest fires and it was confirmed that air masses passing over the location of burning points in Siberia reached Moshiri and Rikubetsu. This paper shows that enhancements of these species were driven by biomass burning in Siberia.     

External and internal carbonic anhydrases in Dunaliella species

Four species of Dunaliella and a carbonic anhydrase deficient mutant of Dunaliella tertiolecta (Butcher), HL 25/8, developed a process for concentrating dissolved inorganic carbon when adapted on air or low CO₂ for 24 h in the light. However, the external carbonic anhydrase activities in Dunaliella species were nil or low compared with those in Chlamydomonas reinhardtii (Danegard) or some Chlorella species. D. tertiolecta had low and about equal levels of external and internal carbonic anhydrase. D. parva (Lerche) and the D. tertiolecta mutant had negligible external carbonic anhydrase. D. viridis (Teodoresco) and D. salina (Teodoresco), high salt tolerant species, had high activities of intenal carbonic anhydrase but low levels of external carbonic anhydrase. Antiserum prepared against the 37 kDa peptide of extracellular carbonic anhydrase from Chlamydomonas reinhardtii was immunoreactive with a polypeptide of 30 kDa in D. tertiolecta and its salt sensitive external carbonic anhydrase (CA) mutant HL 25/8. External CA activity from D. tertiolecta was stimulated about three-fold, by including 0.5 M NaCl in the assay medium, while internal CA was not significantly affected by NaCl. External CA activities in the other species were insensitive to NaCl, while their internal activities were 90% inhibited by 0.5 M NaCl. Sorbitol only partly replaced NaCl in stimulating the external CA from D. tertiolecta. These experiments were performed with Dunaliella spp. grown in controlled laboratory cultures during September through November 1989.     

Evolution of water chemistry in natural acidic environments in Yangmingshan,Taiwan

In Yangmingshan National Park, located in the northern part of the Taiwan Island, there is a very rare area where fish (Channa asiatica) live in spite of acid environments. The origin of the acid in local acid ponds and rivers and the evolution of the water chemistry are discussed on the basis of sulfur stable isotope ratios and chemical equilibria. One of the sources of the acid is sulfuric acid, which is derived from the oxidation of hydrogen sulfide in volcanic gas gushing out from fumaroles around the area and from acid deposition supplied from Taipei City. It is also derived from the oxidation of pyrite: the sulfur stable isotope ratios of delta 34S of +1@1000 to +4@1000 (relative to CDT) of sulfate in acid pond waters (pH 3-4) could be related to those of hydrogen sulfide in volcanic gas, pyrite in local pond sediments and soils, and sulfate in rain water. One acid source is sulfuric and hydrochloric acids arising in springs from geothermal activity: the delta 34S values were characterised by +13@1000 to +17@1000 sulfate-S, which was provided by a disproportionation reaction of sulfur dioxide in the depths. Another acid source could be the oxidation of iron(II). Under acidic conditions, the water-rock reaction gives rise to high concentrations of aluminium and iron. While flowing down surface streams, iron(II) is oxidised to iron(III) and then hydrolysed to cause further acidification under oxic conditions. The concentrations of iron and aluminium are controlled by redox and dissolution equilibria.     

Biogeochemical properties and potential risk of shallow arsenic-rich sediment layers to groundwater quality in Western Bangladesh

Environmental Geochemistry and Health - The arsenic-contaminated groundwater has attracted attention in much south and southeast Asian deltas, however, mainly on the deep aquifers. Here, arsenic...     

The generative power of metaphor: long‐term action research on disaster recovery in a small Japanese village

Disaster recovery is a dynamic process of creating, maintaining, and changing the meaningful context of survivors. It is completed when they redevelop their self‐reliance and resume managing their social relations with a sense of community. This study employed action research to examine how researchers and survivors collaborated to change disaster recovery through the generative power of metaphor in a small village in Japan that experienced the Niigata–Chuetsu earthquake on 23 October 2004. It outlines long‐term collaborative practices as survivors undertook new activities owing to the power of the metaphor of ‘school’. Once ‘school’ was adopted as the metaphor for where survivors learnt new skills and passed on traditional knowledge, they created new metaphors and performed new activities independently, which is critical for recovery as it demonstrates self‐reliance. The paper assesses the reasons why generative metaphors worked effectively in this case and highlights some academic and practical implications for disaster recovery.     

Photodegradation of Poly(lactic acid) Stereocomplex by UV-Irradiation

Neat poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) films and PLLA/PDLA blend films were prepared by solution casting, and their photodegradation by UV-irradiation was investigated using wide-angle X-ray scattering (WAXS), gel permeation chromatography, differential scanning calorimetry, tensile testing, and polarized optical microscopy. The PLLA/PDLA blend film was more photodegradation-resistant than the neat PLLA and PDLA films when photodegradation was monitored by molecular weight, melting temperature, and WAXS crystalline peak positions. This indicates that the chains in both amorphous and crystalline regions of the PLLA/PDLA blend film were photo-cleavage-resistant compared to those of the neat PLLA and PDLA films. The changes in melting temperature and WAXS crystalline peak positions before and after photodegradation respectively indicated the increased crystalline lattice disorder and the decreased crystalline lattice sizes of the neat PLLA and PDLA films, whereas these changes were insignificant for the blend films. Photodegradation caused no significant change in tensile properties, with the exception of significant decreases in the tensile strength and elongation at break of PLLA/PDLA blend film. However, the tensile strength and elongation at break of the PLLA/PDLA blend film retained higher values compared to those of the neat PLLA and PDLA films during photodegradation. In spite of the slower photodegradation of the PLLA/PDLA blend film traced by M _n, T _m, and WAXS crystalline peak positions than that of neat PLLA and PDLA films, the rapid decrease in tensile strength and elongation at break of the former than that of the latter should be due to the highly-ordered structural difference between them, i.e., the three dimensional dry gel of the former and the spherulites of the latter.     

Plutonium(VI) accumulation and reduction by lichen biomass: correlation with U(VI)

The uptake of plutonium(VI) and uranium(VI) by lichen biomass was studied in the foliose lichen Parmotrema tinctorum to elucidate the migration behavior of Pu and U in the terrestrial environment. Pu and U uptake by P. tinctorum averaged 0.040+/-0.010 and 0.055+/-0.015 g gdry (-1), respectively, after 96 h incubation with 4.0 x 10(14) mol 1(-1) Pu solutions of pH 3, 4 and 5. SEM observations showed that the accumulated Pu is evenly distributed on the upper and lower surfaces of P. tinctorum, in contrast to U(VI), which accumulated in both cortical and medullary layers. UV/VIS absorption spectroscopy demonstrates that a fraction of Pu(VI) in the solution is reduced to Pu(V) by the organic substances released from P. tinctorum, and the accumulated Pu on the surface is reduced to Pu(IV), while U(VI) keeps the oxidation state of VI. Since the solubility of Pu(IV) hydroxides is very low, reduced Pu(VI) does not penetrate to the medullary layers, but is probably precipitated as Pu(IV) hydroxides on the cortical lichen surface. It is concluded that the uptake and reduction of Pu(VI) by lichens is important to determine the mobilization and oxidation states of Pu in the terrestrial environment.     

Sonochemical degradation of 2,3,7,8-tetrachlorodibenzo-p-dioxins in aqueous solution with Fe(III)/UV system

2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD) was rapidly decreased by sonication in aqueous solution. The degradation efficiency was strongly influenced by ultrasonic power and reaction temperature. An initial 2,3,7,8-TeCDD concentration of 20 ng l(-1) was completely degraded within 60 min under sonochemical conditions using a 20 kHz frequency with a 150 W ultrasound power. The activation energy is 21.9 kJ/mol in the temperature range of 10-40 degrees C, suggesting a diffusion-controlled reaction. To increase the efficiency of 2,3,7,8-TeCDD treatment, degradation system combined ultrasound with Fe(III) (2 x 10(-4)mol l(-1)) and UV irradiation. Both UV and Fe(III) induced Fenton, Fenton-like and photo-Fenton reactions, leading to additional OH radicals and rapid 2,3,7,8-TeCDD removal.