Application of the rescue number to the evaluation of remediation technologies for contaminated ground

An improved rescue number, RN_SOIL, which is an indicator for evaluating remediation technologies for contaminated ground that is based on both the risk and the remediation cost, is proposed as a tool of risk communication. The risk posed by contaminated ground is indicated by the figure of treatment priority at time t, FTP(t), which represents the human health risk as the number of people affected by the contaminated ground at time t during the remediation process. The calculation of the value of FTP(t) is based on exposure to contaminants that have migrated through environmental media from the contaminated ground, and is estimated by using a CalTOX model and the Monte Carlo method. The integration of FTP(t) with time, which represents the cumulative number of people affected by the contaminated ground, is used to estimate the performance of individual remediation technologies in risk reduction. The figure of unprocessibility for waste (FUW), which represents difficulties in remediation, is expressed as the remediation cost. FUW is estimated by using actual costs per unit volume of remediated soil. As an overall performance value, the rescue number for each remediation technology for contaminated ground (RN_SOIL) is calculated by multiplication of the integral FTP(t) by FUW. Smaller values of RN_SOIL are judged to indicate a better technology. The rescue index (RI), calculated as the ratio of the reduction of the integral FTP(t) to FUW, indicates the cost-effectiveness of the remediation technologies. Successful estimation of the indices (FTP(t), integral FTP(t), FUW, RN_SOIL and RI) demonstrate the usefulness of these indices in risk communication.Part of this paper was presented at 13th meeting of Japan Society of Waste Management Experts (2002)     

Unique aluminosilicate-based natural nanoparticles in the volcanogenic Goshiki-numa pond

We report here the occurrence of uniquely shaped nanoparticles newly discovered in natural ponds. Nanoparticles originate from the Goshiki-numa pond community in Japan, where volcanic activity facilitated the formation of four specific ponds. We built a steric three-dimensional image of nanoparticles by integrating 120 transmission-electron-microscope image fragments obtained from various angle ranges. The thick-walled, cylindrically shaped particle has an outer diameter that measures approximately 40 nm and a length that measures 70 nm. A 10-nm-thick wall surrounds a 30 nm hole located in the particle centre. Particles are composed of an aluminium silicate-based material with an Al₂O₃:SiO₂ ratio of 2:1. They also exhibit an amorphous X-ray diffraction pattern. Although the water solubility characteristics and the infrared spectrum of these newly discovered particles resembles imogolite, these two materials do not have identical structural characteristics.     

Surfactant Treatment for Efficient Gene Detection of Enteric Viruses and Indicators in Surface Water Concentrated by Ultrafiltration

Food and Environmental Virology - The hollow fiber ultrafiltration (HFUF)-based microbial concentration method is widely applied for monitoring pathogenic viruses and microbial indicators in...     

Physicochemical characteristics of carbonaceous adsorbent for dioxin-like polychlorinated biphenyl adsorption

It has been known that dioxin-like polychlorinated biphenyls (DL-PCBs) are present in almost all types of environments worldwide. Activated carbon treatment has been expected for the removal of DL-PCBs because it is a simple and low-cost removal technology. In the present study, the physicochemical properties of activated carbon were investigated to identify the characteristics of 16 different types of activated carbon on adsorption properties for DL-PCBs. To accomplish this, micropore volume, and pore diameter were calculated by t-plot analysis and the mesopore volume was analyzed by the Barrett-Joyner-Halenda (BJH) method. In addition, the Brunauer-Emmett-Teller (BET) surface area, pH, metal elements, and surface acid functional groups were analyzed. Then, adsorption experiments using DL-PCB in hexane solution were conducted, and the relationship between adsorption and physicochemical properties of activated carbon was investigated. The results showed that activated carbons having a surface area of 700-1200 m² g⁻¹ and micropores with diameters of about 0.7-0.8 nm exhibited high activity for the adsorption of PCBs. The results also clearly showed that the mesopore volume of activated carbon influenced the adsorption rate and the equilibrium adsorption.     

Investigation of an accidental explosion due to unintended mixing involving reactive chemicals at a waste storage tank

An accidental explosion occurred in a waste storage tank at an incineration plant in Kawasaki, Japan, on May 11, 1997. The accident was caused primarily by unintended mixing involving reactive chemicals, such as organic peroxides (POs) and acrylonitrile (AN). The PO initiated polymerization of AN and the heat released during the polymerization led to a runaway reaction and explosion. POs are widely used in the chemical industry and can be self-reactive and hazardous when mixed with other chemicals such as acids and alkalis. The goal of this study was to obtain a better understanding of the mixing hazard of chemicals through an evaluation of POs with other chemicals using conventional experimental techniques such as glass test-tube tests, Dewar vessel tests, and differential scanning calorimetry (DSC). Seven types of POs were mixed with AN. Test results were classified into four ranks based on the hazard criteria. In addition, di(2-ethylhexyl)-peroxydicarbonate/AN mixtures were investigated in detail and the influences of the mixing ratio and the stirring rate were examined.     

Novel enzymatic activity of cell free extract from thermophilic Geobacillus sp. UZO 3 catalyzes reductive cleavage of diaryl ether bonds of 2,7-dichlorodibenzo-p-dioxin

We characterized the ability of the cell free extract from polychlorinated dibenzo-p-dioxins degrading bacterium Geobacillus sp. UZO 3 to reduce even highly chlorinated dibenzo-p-dioxins such as octachlorodibenzo-p-dioxins in incineration fly ash. The degradation of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) as a model dioxin catalyzed by the cell free extract from this strain implicates that the ether bonds of 2,7-DCDD molecule undergo reductive cleavage, since 4′,5-dichloro-2-hydroxydiphenyl ether and 4-chlorophenol were detected as intermediate products of 2,7-DCDD degradation.     

Hydrothermal treatment and characterization of model food garbage,focusing on the effect of additional foreign matter on internal temperature,pressure and products

Hydrothermal treatment of model food garbage focusing on the effects of additional foreign matter has been performed in subcritical conditions as a pretreatment for the next step, i.e., the bio-processing and production of liquid feed or fertilizer. Using the hydrothermal technique, we studied the temporal change in internal temperature and pressure in a reactor on the elapsed heating time to check the equipment safety in terms of temperature and pressure. The gaseous and water-soluble liquid was also characterized to investigate the feasibility of retrieving valuable chemicals and emitting environmentally hazardous substances. From the changes in the internal temperature and pressure curve, the maximum temperature and pressure were 196 °C and 1.42 MPa for 30-min elapsed heating time, which was below the predefined temperature limits of 200 °C and pressure of 1.55 MPa. No such irregular behavior was observed in the temperature and pressure curve except that it was a little different for the foreign matter detergent, which also was within the limits. The qualitative and quantitative analysis of end products showed that the emitted malodorous substances and chemicals were further below the threshold levels for Japan.     

Anaerobic biodegradation of 4-alkylphenols in a paddy soil microcosm supplemented with nitrate

Anaerobic degradation of phenol, p-cresol, 4-n-propylphenol (n-PP), 4-i-propylphenol (i-PP), 4-n-butylphenol (n-BP) and 4-sec-butylphenol (sec-BP) was observed in a paddy soil supplemented with nitrate. We detected the metabolites 4′-hydroxypropiophenone (HPP) from n-PP, 4-i-propenylphenol from i-PP, and 4-(1-butenyl)phenol and 4′-hydroxybutyrophenone (HBP) from n-BP. Compared with the original soils, Betaproteobacteria became predominant in the microcosm during the degradation of phenol and p-cresol whereas no remarkable change was observed in the community degrading propylphenols and butylphenols. The microcosm, however, did not degrade 4-t-butylphenol (t-BP), 4-t-octylphenol (t-OP) and 4-n-octylphenol (n-OP). Paddy soil supplemented with sulfate or iron (III) as electron acceptors did not degrade phenol and 4-alkylphenols with the exception of the degradation of p-cresol in sulfate-reducing conditions. It was demonstrated for the first time that anaerobic microbial degradation of alkylphenols, in a paddy soil supplemented with nitrate as an electron acceptor, occurred via oxidation of the alpha carbon in the alkyl chain.     

Prenatal diagnosis of tyrosinase-negative oculocutaneous albinism by an electron microscopic dopa reaction test of fetal skin

An electron microscopic DOPA reaction test of fetal skin was used for the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism (OCA). The subject was a 34-year-old Japanese woman in her second pregnancy. Her first child, born in 1982, had been previously examined and confirmed to have tyrosinase-negative OCA. The parents requested a prenatal diagnosis and we sampled skin from the upper trunk of the fetus. On conventional electron microscopy, the development of melanosomes in interfollicular melanocytes had progressed no further than stage II. Fetal skin samples incubated with L-DOPA solution indicated a lack of tyrosinase activity and showed that the melanosomes had not progressed beyond stage II. In skin samples from the trunks of three Japanese fetuses aborted for other reasons at 19–20 weeks of gestation, most premature melanosomes were further melanized to stage IV after incubation with L-DOPA solution. A prenatal diagnosis of tyrosinase-negative OCA was made. The parents requested a termination and skin biopsies of the abortus confirmed the diagnosis. This study shows that tyrosinase is normally present in melanocytes of the fetal epidermis at 20 weeks' gestation, and that the electron microscopic DOPA reaction test of a fetal skin biopsy specimen is safe and practical, and provides reliable information for making a prenatal diagnosis of tyrosinase-negative OCA in the second trimester.