Size-separated aerosol number concentrations and water-soluble constituents as well as precipitation chemistry were simultaneously measured in Toyama, the Hokuriku district, near the coast of the Japan Sea, in 2004. The number concentrations of coarse particles were significantly high in the spring, which was due to Asian dust events called Kosa in Japanese. Particulate Ca²⁺, which was mostly present in the coarse-mode particles, was also significantly high in March and April. On the other hand, the concentration of NH₄⁺ and SO₄^2-, which mainly exists as the accumulation-mode particles was higher in the summer. The concentration of SO₄^2- in the coarse-mode particles also was not higher in the spring than in the summer. The pollutants adsorbed on Kosa particles, may not significantly affect the air quality in the Hokuriku district. High concentration of Ca²⁺ in the precipitation was observed from February to April. The acidic species in the precipitation were neutralized by the Kosa particles.

View full abstract

The addition of urea was studied as one of the preparation methods for porous phosphate particles. Urea was added to the preparation of lanthanum polyphosphate from lanthanum nitrate and sodium polyphosphate solutions. The precipitations prepared in various concentration of urea and their thermal products were estimated from the view of the chemical composition, powder and acidic properties. The addition of urea on preparation of lanthanum polyphosphate produced the increase of about 20 nm-radius pores without the change of chemical composition of phosphates. The large amount of urea covered the pore of lanthanum polyphosphate. The amount of included urea in lanthanum polyphosphate was estimated from NH₃-TPD curves. The adsorption of trimethylamine decreased on lanthanum polyphosphate because of the remaining of urea.

View full abstract

In this study, laboratory model experiments on the interactions of Cr with natural ecological restoration substances were carried out to estimate optimum conditions for the reduction of Cr in soils and/or waters. For natural ecological restoration substances, humic substances (humic acid and fulvic acid) and clay minerals (bentonite and imogolite) were used. The experiments, performed at pH 4-8, yielded the following results: (1) Cr(VI) was reduced to Cr(III) by the humic substances; moreover, the reduction ability of the humic substances decreased with increasing pH. (2) The complexation of Cr(III) proceeded faster than the reduction of Cr(VI) and reached a maximum at pH 5. (3) Cr(III) was best removed at pH 4 and 5 by bentonite, but the removal ratio decreased with increasing pH. Furthermore, the removal effect of bentonite decreased with the addition of a humic substance. (4) While Cr(VI) was never removed by bentonite, the removal was slightly improved by the addition of a humic substance and an increase in pH. (5) An effect of imogolite on the removal of Cr(VI) was observed at pH 4 and 5. Reaching a maximum at pH 4, the effect was not indicated at pH 6-8.

View full abstract

A method for solid phase extraction of trace metals such as Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn using nanometer sized alumina coated with chromotropic acid prior to determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been developed. Various parameters influencing on the separation and preconcentration of trace metals, such as pH, flow rate, sample voulme and concentration of eluent were studied. The maximun adsorption capacity of the solid phase adsorption material was 10.3, 11.3, 14.5, 16.4, 15.1, 11.7, 15.4 and 16.8 mg/g for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively. The detection limits for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were found to be 0.14, 0.62, 0.22, 0.54, 0.27, 0.28, 0.53 and 0.38 ng/ml, respectively. The preconcentration factor was obtained in the range of 50–100 for all studied metal ions. Coexisting ions over high concentration range did not show any significant effect on the determination of aforesaid metal ions. The accuracy of the proposed method was tested by standard reference materials (NIST 1643e: water, NIST 1573a: tomato leaves and NIST 1568a: rice flour), and the results agreed well with the certified values.

View full abstract

The working environment in a ribbed rubber smoke sheets (RSS) cooperative in Songkhla province in Thailand, which is under serious air pollution by smoke from the biomass burning in rubber sheet drying process, has been monitored focusing on pollutants such as particle-bound PAHs as well as NO₂, SO₂ and VOCs. Both size fractionated particles and total suspended particulates (TSP) have been sampled using air samplers. The personal exposure was also investigated using personal samplers. Workers in 22 cooperatives were interviewed to discuss their opinion on the working environment, health problems and the demand for pollution control. A preliminary investigation into the prevalence of worker's respiratory symptom was also done.
The average PAHs concentration was more than 5 times larger in the workplace than in the ambient. Workers' main discomforts were smoke and odor. The priorities of pollution control device were high performance, ease of use, and convenience in maintenance, respectively. From the respiratory symptoms questionnaire, the prevalence of cough, productive cough, chest discomfort, wheezing sound and cold were evaluated as 64.7%, 49%, 51%, 13.7% and 66.7%, respectively. The upper respiratory symptoms were very likely to be related to pollutants in the workplace.

View full abstract

The fate of hydrophobic pollutants in rivers depends on the partition of pollutants between river water and sediments. Understanding the partition of pollutants in a sediment-water system is important for the environmental quality management of a water environment. The concentration of polycyclic aromatic hydrocarbons (PAHs) in water and sediment was monitored at downstream locations of the two main rivers of Kanazawa City, the Asano and Sai Rivers. Sediments were classified into three different particle size fractions. The estimated sediment-water partition coefficient, K_d was found to be correlated with the organic carbon contents of the sediment. The organic carbon normalized partition coefficient K_oc was calculated as K_d/f_oc, where f_oc is the content of sedimentary organic carbon values. No apparent relation was found between the K_oc and sediment particle size. The K_oc and K_ow values of PAHs except for Benzo[k]fluoranthene were fitted to the linear free energy relationship logK_oc = alogK_ow + b. Value of a = 0.562 and b = 3.55 for the Asano River and a = 0.814 and b = 2.19 for the Sai River were obtained. These results suggest that the organic carbon content, not the particle size, controls the sediment-water partition coefficient.

View full abstract

The most common catalysts for biodiesel production are homogeneous catalysts such as NaOH and KOH. In the present study, a comparison was performed in the different base and acid catalysts (NaOH, KOH, Na₂CO₃, K₂CO₃, H₂SO₄ and CH₃COOH) for methanolysis and ethanolysis of triolein by means of ultrasonic cavitation. All experiments were carried out under the same experimental condition in a batch ultrasonic reactor at 25°C, where the molar ratio of alcohol to triolein and catalyst concentration were 6:1 and 1 wt%, respectively. The biodiesel conversion was near 100% for all base catalysts. However, it was found that the conversion was very low in the case of acid catalyst (H₂SO₄) and no conversion was observed in the case of CH₃COOH. It was found that the catalytic activity for methanolysis and ethanolysis of triolein was in the order of CH₃COOH (no conversion) ‹ H₂SO₄ ‹ K₂CO₃ ‹ Na₂CO₃ ‹ KOH = NaOH under the ultrasonic irradiation condition.

View full abstract

Toyama Prefectural University, the prefecture-owned university, offers an advanced environmental education program to the students. Many of them are supported by local communities in terms of personnel and technology. In this research, effectiveness of a Community-Supported Environmental Education Program, including the field tour, the field research, the forum and the eco-tour, was elucidated by the questionnaires to the students and by the impressions described in the reports by the students. The effectiveness of the education program supported by the local communities was confirmed, while it became clear that some improvements are still required to offer more attractive programs to the student, for example, a program established by both the university and the local community based on bilateral relationships.

View full abstract

The availability of used roofing tiles as fine aggregate for concrete was evaluated in terms of compressive strength. Roofing tile scrap with a diameter of less than 5 mm was mixed as fine aggregate for fresh concrete as a substitution for sand. After 28 days of aging, the compressive strength of the sample pieces of concrete was measured under JIS A1108. According to the experimental results, the cement/water ratio highly influenced the compressive strength of the concrete, indicating that the water content of the roofing tile aggregate should be controlled. We propose the Time Domain Reflectometry (TDR) method for measuring the water content of roofing tile scrap as an expeditious method on site. Our proposed method enables the production of concrete mixed with roofing tile scrap with higher compressive strength than ordinary concrete without roofing tile scrap.

View full abstract

The soils in the watersheds on Kureha Hill, Toyama, Japan have been acidified by high-concentration of nitrate owing to nitrogen-saturation. Generally, nitrifiers inactivate their nitrification at a pH level below 5. However, the nitrifiers present in the soils of Kureha Hill continue to be active at the pH of 3.1. The purpose of this study is to identify the species of ammonia-oxidizing bacteria (AOB) as nitrifiers present in the highly-acidified soils of Kureha Hill.
The polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method, targeting 16S-rDNA combined with DNA-sequencing analysis was applied to identify these AOB. The DNA was extracted from the soil of Kureha Hill, which was incubated in an incubator for 660 days to increase their AOB population. 16S-rDNA of the extracted DNA was PCR-amplified with the primers targeting that of AOB. The amplified 16S-rDNA was separated by the DGGE method, in which the different constitution of 16S-rDNA can be separated into bands on a denaturing gradient gel by electrophoresis. As a result, two different bands were observed on the gel, which meant that two types of AOB participated in the nitrification in the incubated soil. DNA-sequencing analysis revealed that one of the types of AOB showed 98% identity with that of Nitrosospira. sp. En13.

View full abstract

Flue gas desulfurization gypsum (FGDG), a by-product of wet and semi-dry desulfurization processes, has been used as alkali soil amendments in northeastern China. In this research, the continuity of FGDG as alkali soil amendments is confirmed from the point of view of corn production and parameters such as pH, EC and ESP. Moreover, correlation coefficients between various measured values indicate the soil reclamation mechanism. It was found that alkali soil reclamation effects achieved by using wet and semi-dry desulfurization gypsum last at least eight and seven years, respectively.

View full abstract

A pure culture of any microbial species has not demonstrated phosphorus removal at the same level as EBPR activated sludge in the anaerobic-aerobic (oxic) wastewater treatment process. The reasons for differences in phosphorus profiles between pure cultures of specific species and activated sludge include (1) growth and preservation on agar media, (2) pre-culture with large growth rate, and (3) cultivation with a high concentration of inflow substrate and a low dilution rate without supernatant effluent. The third point was examined experimentally in this study. The results achieved from the lab-scale experiments showed that it was apparent that mixed liquor withdraw operation (MWO) caused deterioration of phosphorus removal in the anaerobic-oxic process, but could enhance phosphorus removal under some specific conditions. High concentrations of sodium, potassium and ammonium nitrogen in the reactors could not be a reason for the deterioration of phosphorus removal in the anaerobic-oxic process with MWO. Similarly, inorganic and organic materials which might be produced during autoclave sterilization did not seem to be a reason for the phosphorus removal deficiency in the anaerobic-oxic process with MWO. Phosphorus to carbon (P/C) ratio of the inflow and aeration level in the aerobic phase were crucial for enhancing phosphorus removal of the anaerobic-oxic process with MWO.

View full abstract

In order to investigate the quantitative change, the quality change and the distribution of dissolved organic matter (DOM) in Toyama Bay, water samples from 7 stations in the coastal area, one station at the center in the bay, one station out of the bay and its inflowing two rivers were taken from September, 2003 to March, 2005. The filtered organic matter was fractionated into hydrophilic and hydrophobic bases (Hi+HoB), hydrophobic acids (HoA) and hydrophobic neutral (HoN) components by DAX-8 resin.
The concentration of DOM component in the bay tended to be high in summer and low in winter. The concentrations of DOM in two river waters did not show clear seasonal changes. In the coastal and central sampling points, the DOM concentrations had positive correlations with water temperature and chlorophyll-a concentration. The results suggested that internal production in the bay greatly contributed to the seasonal change of DOM concentration.

View full abstract