Semiquantitative color profiling of soils over a land degradation gradient in Sakaerat, Thailand

In this study, we attempted multivariate color profiling of soils over a land degradation gradient represented by dry evergreen forest (original vegetation), dry deciduous forest (moderately disturbed by fire), and bare ground (severely degraded) in Sakaerat, Thailand. The soils were sampled in a dry-to-wet seasonal transition. Values of the red–green–blue (RGB), cyan–magenta–yellow–key black (CMYK), L*a*b*, and hue–intensity–saturation (HIS) color models were determined using the digital software Adobe Photoshop^TM. Land degradation produced significant variations (p?R, C, Y, L*, a*, b*, S, and I values (p?p?R, G, B, C, M, K, L*, b*, and I values. In discriminating the soils, the color models did not differ in discriminatory power, while discriminatory power was affected by seasonal changes. Most color variation patterns had nonlinear relationships with the intensity of the land degradation gradient, due to effects of fire that darkened the deciduous forest soil, masking the nature of the soil as the intermediate between the evergreen forest and the bare ground soils. Taking these findings into account, the utilization of color profiling of soils in land conservation and rehabilitation is discussed.     

Plutonium isotopes concentration in seawater and bottom sediment off the Pacific coast of Aomori sea area during 1991-2005

A radioactivity survey was launched in 1991 to determine the background levels of ^239+240Pu in the marine environment off a commercial spent nuclear fuel reprocessing plant before full operation of the facility. Particular attention was focused on the ²⁴⁰Pu/²³⁹Pu atom ratio in seawater and bottom sediment to identify the origins of Pu isotopes. The concentration of ^239+240Pu was almost uniform in surface water, decreasing slowly over time. Conversely, the ^239+240Pu concentration varied markedly in the bottom water and was dependent upon the sampling point, with higher concentrations of ^239+240Pu observed in the bottom water sample at sampling points having greater depth. The ²⁴⁰Pu/²³⁹Pu atom ratio in the seawater and sediment samples was higher than that of global fallout Pu, and comparable with the data in the other sea area around Japan which has likely been affected by close-in fallout Pu originating from the Pacific Proving Grounds. The ²⁴⁰Pu/²³⁹Pu atom ratio in bottom sediment samples decreased with sea depth. The land-originated Pu is not considered as the reason of the increasing ^239+240Pu concentration and also decreasing the ²⁴⁰Pu/²³⁹Pu atom ratio with sea depth, and further study is required to clarify it.     

Thymic involution produced by diesel exhaust particles and their constituents in mice

Epidemiological studies suggest that diesel exhaust particles (DEP) contribute to an increase in allergic diseases. To assess the effects of DEP on the central immune system, mice were exposed to DEP by intraperitoneal (IP) administration. Exposure to DEP resulted in severe thymic involution accompanied by a reduction in the number of thymocytes, especially in cortical CD4⁺CD8⁺ double positive and double negative subsets. Core carbon particles associated with a mixture of chemical compounds in DEP did not appear to be responsible for the DEP-induced thymic involution because carbon graphite does not affect neither the number nor the CD4/CD8 profile of thymocytes. Extraction of DEP by ether, acidic and basic solvents showed that several independent fractions including the neutral ether fraction, which contains polycyclic aromatic hydrocarbons (PAH), induced thymic involution. Among major PAH components of DEP, benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP), and benzo[k]fluoranthene (BkF) were very potent inducers of thymic involution at an ED50 of less than 100?ng per mouse body. Nonetheless, DEP treatment of mice with targeted disruption of genes encoding the aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), or microsomal epoxide hydolase (mEH) indicated that DEP produced thymic involution even in the absence of PAH-induced AHR/ARNT signal transduction or mEH-mediated PAH catabolism. On the other hand, BaP-mediated thymic involution was completely dependent on AHR, partially dependent on ARNT in T cells, and independent of mEH. These results indicate that DEP-induced thymic involution is mediated both by PAH-AHR/ARNT-dependent and -independent mechanisms.     

Eco-hydrodynamic Modelling of Chini Lake: Model Description

In this study, we coupled a three-dimensional hydrodynamic model with an ecosystem model and applied it to the shallow complex floodplain wetland of Chini Lake in Malaysia. Our objective was to provide a better understanding of the lake’s ecosystem dynamics under different forcing mechanisms. Simulations and validation were performed over a dry month period. Wind speed ranged between 0 and 7.7 m s^?1, whilst air temperature ranged between 22.0 and 35.6 °C. Advective transport driven by wind stress was the dominant physical force that shaped the water quality variations during the dry season. Convective circulation intermittently influenced the circulation during calm conditions. Nutrient concentration and stratification of dissolved oxygen (DO) varied between the lakes. Wind events saw patterns of the surface DO concentrations move spatially in the direction of the wind. The ecosystem model simulation suggested that the water quality in Chini Lake was influenced by macrophyte production, although the dissolved and particulate organic carbon accounted for the major fraction of organic matter content in the lake.     

Modification of ecological footprint evaluation method to include non-renewable resource consumption using thermodynamic approach

This study is to modify the ecological footprint methodology by incorporating non-renewable or abiotic resources as an additional category. The use of abiotic resources can be quantified as global hectare by using thermodynamic approaches. A detailed case study on various countries including Australia, Belgium, Brazil, Canada, Japan, USA, and Vietnam shows the advantage of using the new modified ecological footprint (EF) as an indicator for sustainable development. The modified EF includes not only biotic resources, but also the abiotic resources. The case study indicates that the modified EF differs from the traditional EF up to 123% in the case of Belgium, and 90% in the case of Australia. For developing countries such as Brazil and Vietnam, the differences are relatively smaller (21% for Brazil and 9.4% for Vietnam). The estimated total ecological footprint of the world using the new method implies more serious problems associated with over consumption than using results from the original ecological footprint method.     

Indirect identification of an unstable intermediate in γ-HCH degradation by Pseudomonas paucimobilis UT26

While a postulated intermediate, 1,3,4,5-tetrachlorocyclohexa-1,4-diene(1,4-TCDN), is one of the key-compounds in γ-hexachlorocyclohexane(γ-HCH) degradation by Pseudomonas paucimobilis UT26(UT26), it has neither been isolated nor identified yet. Thus, an indirect identification was attempted to demonstrate its existence by a chemical oxidation of the microbial degradation products in situ.

1,2,4,5-Tetrachlorobenzene(1,2,4,5-TeCB) was newly produced by the chemical oxidation with hydrogen peroxide under iron(II) of W medium containing degradation products in situ of γ-1,3,4,5,6-pentachlorocyclohexene(γ-PCCH) by Escherichia coli MV1184(E. coli) which possesses the dehydrochlorinating activity of UT26. The chemical oxidation required the preceding enzymatic reactions to γ-PCCH by E. coli for the production of 1,2,4,5-TeCB. In facts, 1,2,4,5-TeCB was not produced from γ-PCCH by either of the chemical or enzymatic reaction alone.

Considering these results and the fact that hydrogen peroxide is known to dehydrogenate chemical compounds, it was concluded that 1,2,4,5-TeCB was produced directly from the unstable intermediate, 1,4-TCDN, on yielded from γ-PCCH by an enzymatic dehydrochlorination.     

Steel slag quality control for road construction aggregates and its environmental impact: case study of Vietnamese steel industry—leaching of heavy metals from steel-making slag

Environmental Science and Pollution Research - Steel slag is an industrial by product of steel manufacturing processes and has been widely utilized within civil and construction materials for road...     

Principal components derived from soil physicochemical data explained a land degradation gradient,and suggested the applicability of new indexes for estimation of soil productivity in the Sakaerat Environmental Research Station,Thailand

To find a principal component (PC) that quantifies the degree of soil degradation, we analyzed various physicochemical characteristics of soils over a land degradation gradient related to aboveground vegetation in the Sakacrat Environmental Research Station (SERS), Thailand. The aboveground vegetative types representing the degradation gradient were bare ground (BG, highly degraded), dry dipterocarp forest (DDF, moderately disturbed) and dry evergreen forest (DEF, the original vegetation). Soils under these vegetative types were sampled in February (dry season). March just after temporal precipitation) and June (rainy season) 2001. Through the period of this research, the degradation was consistently explained by sandy texture, high bulk density, lower pH, high exchangeable acidity, poor mineral and organic nutrients and dryness. Principal component analysis (PCA) was applied to determine significant principal components (PCs) that clarify the differences in soil properties between the vegetative types and between the timing of soil sampling. The PC loadings suggested that the first PC was the component that indicates total fertility of soil in the site, while the fifth PC indicates the dry to wet seasonal transition. The first PC was named the total fertility component (TFC). The linear regression between the TFC score and recently proposed indexes, the soil fertility index (SFI) or the soil evaluation factor (SEF), was highly significant (p < 0.001), indicating that the SFI and the SEF are applicable to measuring total fertility of soils in the SERS.     

Comparative study of the effects of infrasound and low-frequency sound with those of audible sound on sleep

In order to compare the effects of infrasound and low-frequency sound on sleep with those of audible sound, healthy students were exposed to two kinds of sound, (a) infrasound and low-frequency sound (10, 20, 40, and 60 Hz), and (b) synthesized traffic noise with peak sound pressure level in low-frequency range (sound composed of low and audible frequency), throughout their sleep with the recording of the students' EEG. The effects were evaluated by the “reaction rate”. Concerning sound (a), the sound pressure level which causes the reactions of over 50% for the first time was used as the threshold sound pressure level signifying the occurrence of sleep disturbance. The threshold sound pressure levels of 10 and 20 Hz could not be evaluated. The threshold sound pressure levels of 40 and 63 Hz were 95 and 90 dB, respectively. With both sounds, the reaction rate was the highest in sleep stage 1 and the lowest in sleep stage 3+4. The pattern of sleep was little affected by sound (a). On the other hand, it was considerably affected by sound (b). These results suggest that audible sound has more harmful effects on sleep, compared with infrasound and low-frequency sound.