High (210)Po atmospheric deposition flux in the subtropical coastal area of Japan

Bulk atmospheric deposition fluxes of (210)Po and (210)Pb were measured at three coastal regions of Japan, the Pacific Ocean coastal area of the Japanese mainland (Odawa Bay), the Chinese continental side of Japanese coastal area (Tsuyazaki), and an isolated island near Okinawa (Akajima). Wet and dry fallout collectors were continuously deployed from September 1997 through August 1998 for periods of 3 to 31 days depending on the frequency of precipitation events. Annual (210)Pb deposition fluxes at Odawa Bay (35 degrees N 139 degrees E), Tsuyazaki (33 degrees N 130 degrees E) and Akajima (26 degrees N 127 degrees E) were 73.3+/-8.0, 197+/-35 and 78.5+/-8.0 Bqm(-2)y(-1), respectively. Higher (210)Pb deposition was observed at the Chinese continental side of Japanese coast than at the Pacific Ocean coastal site. The high (210)Pb atmospheric flux at the Chinese continental side coast was thought to be attributable to (222)Rn-rich air-mass transport from the Chinese continent during the winter monsoon. In contrast, the annual (210)Po deposition fluxes at the three study sites were 13.0+/-2.3 (Odawa Bay), 21.9+/-4.4 (Tsuyazaki) and 58.4+/-7.7 (Akajima)Bqm(-2)y(-1), respectively, indicating unusual high (210)Po deposition at Akajima during winter. Anomalous unsupported (210)Po input was observed during summer 1997, suggesting unknown source of (210)Po at this area.     

Heavy metals removal from aqueous solution using carbonaceous K_2S-impregnated adsorbent

A novel carbonaceous adsorbent for heavy metal removal was prepared from raw coal by one-step simple sulfur impregnation using K_2S. Raw coal was mixed with K_2S powder and then heated at 800℃ for 30 min in nitrogen to produce K_2S char. The sulfur content and form in K_2S char were determined, and the ability of K_2S char to adsorb Zn~(2+), Cd~(2+) and Pb~(2+) was examined. The K_2S impregnation was effective at impregnating sulfur into coal, especially in the form of elemental, thiophenic and sulfatic sulfur. The sulfur content of K_2S char was higher than those of raw coal and pyrolysis char. The Zn~(2+) removal in 2.4 mmol/L of Zn~(2+) solution by K_2S char was higher than raw coal with the removal rate of 100%. K_2S char adsorbed Pb~(2+) and Cd~(2+) in 24 mmol/L of Pb~(2+) and Cd~(2+) solution with the removal rate of 97 % and 35 %, respectively. The elution extents of adsorbed Pb~(2+) and Cd~(2+) were zero in distilled water and 27% in 0.1 mol/L HCl solution. These results indicated that an effective adsorbent for heavy metal ions was prepared from coal using K_2S sulfur impregnation, and that the adsorbed metals were strongly retained in K_2S char.     

Arsenic,selenium, and chromium speciation in fly ash

Journal of Material Cycles and Waste Management - Arsenic (As), selenium (Se), and chromium (Cr) are harmful to humans at certain concentrations, and can possibly be eluted from coal ash (fly ash)...     

Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years of continuous operation

The microbial community structures of two mesophilic anaerobic chemostats, one fed with glucose, the other with starch as sole carbon sources, were studied at various dilution rates (0.05–0.25 d^–1 for glucose and 0.025–0.1 d^–1 for starch) during two years continuous operation. In the glucose-fed chemostat, the aceticlastic methanogen Methanosaeta spp. and hydrogenotrophic methanogen Methanoculleus spp. predominated at low dilution rates, whereas Methanosaeta spp. and the hydrogenotrophic Methanobacterium spp. predominated together when dilution rates were greater than 0.1 d^–1. Bacteria affiliated with the phyla Bacteroidetes, Spirochaetes, and Actinobacteria predominated at dilution rates of 0.05, 0.1, and 0.15 d^–1, respectively, while Firmicutes predominated at higher dilution rates (0.2 and 0.25 d^–1). In the starch-fed chemostat, the aceticlastic and hydrogenotrophic methanogens coexisted at all dilution rates. Although bacteria belonging to only two phyla were mainly responsible for starch degradation (Spirochaetes at the dilution rate of 0.08 d^–1 and Firmicutes at other dilution rates), different bacterial genera were identified at different dilution rates. With the exception of Archaea in the glucose-fed chemostat, the band patterns revealed by denaturing gradient gel electrophoresis (DGGE) of the microbial communities in the two chemostats displayed marked changes during long-term operation at a constant dilution rate. The bacterial community changed with changes in the dilution rate, and was erratic during longterm operation in both glucose-fed and starch-fed chemostats.     

A comparative evaluation of wet digestion and dry ashing methods for the determination of some major and minor nutrients in composted manure

The analytical results of 53 manure samples determined by wet digestion and dry ashing procedures were compared in order to evaluate their relative suitability for recovering different nutrient elements in manure and manure compost. Wet digestion recovered greater amounts of phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), and zinc (Zn) in more samples than dry ashing. Nutrient contents in the samples were highly variable, with coefficients of variation (CV) ranging from 38% for magnesium (Mg) to 161% for copper (Cu) analyzed by the wet digestion procedure, and from 47% to 138% for Mg and Cu analyzed by the dry ashing procedure. The mean values of P, K, Ca, Mn, and Zn averaged for the 53 samples were significantly higher using wet digestion than dry ashing procedure, but both procedures recovered comparable amounts of iorn (Fe), Mg, and Cu. Correlations analysis between both procedures for each element showed reasonable to fair agreements for Ca (R ²?=?0.93), K (R ²?=?0.93), P (R ²?=?0.90), Mg (R ²?=?0.84), Fe (R ²?=?0.87), Mn (R ²?=?0.73), and Cu (R ²?=?0.66), but poor agreement for Zn (R ²?=?0.44). The low agreement between procedures for Zn suggests that wet digestion, which gave a higher recovery, should be a preferred procedure for analyzing Zn in manures.     

Estimation of municipal solid waste generation and landfill area in Asian developing countries

In developing Asian countries, the municipal cooperations are unable to handle the increasing amount of municipal solid waste, which into the uncollected waste being spread on roads and in other public areas leading to tremendous pollution and destruction of land and negative impact on human health. Generation of municipal solid waste increases with the rapid urbanization and accelerated economic development with in the rapidly growing advanced technological societies. The nature of municipal solid waste is a term usually applied to a heterogeneous collection group of waste produced in urban areas, the nature of which varies from region to region. The common problem faced by all developing Asian countries, is the disposal of municipal solid waste and availability of land fill site area. Present study explains the correlation analysis of among different factors of municipal solid waste and the objective is to assess the future municipal solid waste stream in Asian developing countries. The other goal of this study was to calculate the future land area that would be required for landfill site disposal in Asian developing countries.     

黄河三角洲湿地土壤微生物群落结构分析

采用末端限制性片段长度多态性分析(T-RFLP)技术和16S rDNA克隆文库的方法,分析了黄河三角洲滨海湿地土壤不同深度细菌和古菌的群落结构.研究表明,随着深度的增加,细菌群落的多样性下降,而古菌群落多样性则有上升的趋势,且土壤的细菌和古菌群落结构都呈现出规律的层状分布.该土壤包括各种硫酸盐还原菌、产甲烷古菌、光合细菌等丰富的细菌和古菌资源.图5参27     

210Pb deposition in the far East Asia: controlling factors of its spatial and temporal variations

In order to better understand the behavior of ²¹⁰Pb deposition in Far East Asia, comprehensive data of monthly ²¹⁰Pb deposition, which includes several time-series and spatial distribution data at 14 stations in Japan and 2 stations in Taiwan, were analyzed. Pb-210 deposition at most of the sites exhibited a typical seasonal change with higher values in winter and lower values in summer; especially, the greatest ²¹⁰Pb deposition in the world occurred in winter at sites beside the Japan Sea. The deposition behavior of ²¹⁰Pb in Far East Asia differed between winter and summer. The meteorological phenomenon peculiar to winter of the Japan Sea side, i.e., formation of the Japan Sea convergence zone, might cause the high ²¹⁰Pb concentration in rainwater, as may heavy snowfall. The ²¹⁰Pb concentration in rainwater showed long-term variability, although this differed between winter and summer. This long-term variability may be related to climatological factors such as El Niño.     

A study on the self-assembly behavior of dark materials from molasses

We have previously demonstrated that dark materials (DM) in acidified molasses are effectively adsorbed to Amberlite XAD7HP resin and are eluted from the resin with 0.1 M sodium hydroxide. In this paper, we have characterized the self-assembly behavior of molasses DM by using dynamic and static light scattering in combination with isoelectric focusing and infrared absorption spectroscopy in order to better understand the resin adsorption mechanism. One of DM derivatives, X-G2, contained carboxyl and hydroxyl groups and had a weight-average molar mass of 9.39?×?10³ to 4.42?×?10⁴ at pH 2.1–11.5. The aggregates retained their spherical shape over the full pH range and the large gyration radius (66.4–80.0 nm) indicated that the inner structure was loosely packed. Furthermore, X-G2 had an isoelectric point of 1.8, and its density increased sharply at pH 5.9 and then approached a nearly constant value under alkaline conditions. In summary, the self-assembly processes of DM are controlled by intermolecular hydrogen-bonding and hydrophobic interactions. The aggregates adsorb to the resin through hydrophobic interactions and are eluted when excess carboxylate anions are generated.     

Roadside Particulate Air Pollution in Bangkok

Abstract

Airborne fine particles of PM_2.5-10 and PM_2.5 in Bangkok, Nonthaburi, and Ayutthaya were measured from December 22, 1998, to March 26, 1999, and from November 30, 1999, to December 2, 1999. Almost all the PM₁₀ values in the high-polluted (H) area exceeded the Thailand National Ambient Air Quality Standards (NAAQS) of 120 μg/m³. The low-polluted (L) area showed low PM₁₀ (34–74 μg/m³ in the daytime and 54–89 μg/m³ at night). PM_2.5 in the H area varied between 82 and 143 μg/m³ in the daytime and between 45 and 146 μg/m³ at night. In the L area, PM_2.5 was quite low both day and night and varied between 24 and 54 μg/m³, lower than the U.S. Environmental Protection Agency (EPA) standard (65 μg/m³). The personal exposure results showed a significantly higher proportion of PM_2.5 to PM₁₀ in the H area than in the L area (H = 0.80 ± 0.08 and L = 0.65 ± 0.04).

Roadside PM₁₀ was measured simultaneously with the Thailand Pollution Control Department (PCD) monitoring station at the same site and at the intersections where police work. The result from dual simultaneous measurements of PM₁₀ showed a good correlation (correlation coefficient: r = 0.93); however, PM levels near the roadside at the intersections were higher than the concentrations at the monitoring station. The relationship between ambient PM level and actual personal exposures was examined. Correlation coefficients between the general ambient outdoors and personal exposure levels were 0.92 for both PM_2.5 and PM₁₀.

Bangkok air quality data for 1997–2000, including 24-hr average PM₁₀, NO₂, SO₂, and O₃ from eight PCD monitoring stations, were analyzed and validated. The annual arithmetic mean PM₁₀ of the PCD data at the roadside monitoring stations for the last 3 years decreased from 130 to 73 μg/m³, whereas the corresponding levels at the general monitoring stations decreased from 90 to 49 μg/m³. The proportion of days when the level of the 24-hr average PM₁₀ exceeded the NAAQS was between 13 and 26% at roadside stations. PCD data showed PM₁₀ was well correlated with NO₂ but not with SO₂, suggesting that automobile exhaust is the main source of the particulate air pollution. The results obtained from the simultaneous measurement of PM_2.5 and PM₁₀ indicate the potential environmental health hazard of fine particles. In conclusion, Bangkok traffic police were exposed to high levels of automobile-derived particulate air pollution.