Analytical survey of arsenic in geothermal waters from sites in Kyushu,Japan, and a method for removing arsenic using magnetite

The objective of this study was to survey the cation and anion contents of geothermal waters to gather fundamental information on geographical variations. Sixteen sites in hot spring areas on the island of Kyushu in Japan were studied. The study focused on the arsenic content of the samples. Very high arsenic concentrations (more than 0.1 mg/l) were detected in most of the geothermal waters sampled. High contents of boron and fluoride (more than 1.0 mg/l) were also detected in some samples. Arsenic removal was performed on a laboratory scale using columns packed with a magnetite-type adsorbent. The reduction of arsenic contamination to a concentration of less than 0.01 mg/l could be achieved in the early stages of adsorption (bed volume = 200).     

Multivariate analyses of the effect of an urban wastewater treatment plant on spatial and temporal variation of water quality and nutrient distribution of a tropical mid-order river

Freshwater resources are increasingly scarce due to human activities, and the understanding of water quality variations at different spatial and temporal scales is necessary for adequate management. Here, we analyze the hypotheses that (1) the presence of a wastewater treatment plant (WWTP) and (2) a polluted tributary that drains downstream from the WWTP change the spatial patterns of physicochemical variables (pH, turbidity, dissolved oxygen, and electrical conductivity) and nutrient concentrations (reactive soluble phosphorus, total phosphorus, nitrogen series, total nitrogen, and total dissolved carbon) along a mid-order river in SE Brazil and that these effects depend on rainfall regime. Six study sites were sampled along almost 4 years to evaluate the impacts of human activities, including sites upstream (1–3) and downstream (5–6) from the WWTP. The impacts were observed presenting an increasing trend from the source (site 1) towards Água Quente stream (site 4, the polluted tributary), with signs of attenuation at site 5 (downstream from both WWTP and site 4) and the river mouth (site 6). Input of nutrients by rural and urban runoff was observed mainly at sites 2 and 3, respectively. At sites 4 and 5, the inputs of both untreated and treated wastewaters increased nutrient concentrations and changed physicochemical variables, with significant impacts to Monjolinho River. Seasonal variations in the measured values were also observed, in agreement with the pluviometric indexes of the region. Univariate analyses suggested no effect of the WWTP for most variables, with continued impacts at sites downstream, but non-parametric multivariate analysis indicated that these sites were recovering to chemical characteristics similar to upstream sites, apparently due to autodepuration. Therefore, multivariate methods that allow rigorous tests of multifactor hypotheses can greatly contribute to determine effects of both point and non-point sources in river systems, thus contributing to freshwater monitoring and management.     

Confirmation of polychlorinated biphenyl (PCB) distribution in the blood and verification of simple quantitative method for PCBs based on specific congeners

We measured the concentration of each polychlorinated biphenyl (PCB) congener in whole blood, plasma and blood cells, and investigated the distribution of PCBs in human blood using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The PCB concentrations in plasma and whole blood in terms of lipid concentrations were almost equal, with a correlation coefficient of r = 0.972. In the blood, the ratio of PCBs in blood cells to those in plasma was generally about 1:9 and the congener distribution patterns in blood cells and plasma were similar.We performed verification of a simple mass screening method by obtaining information on the main PCB congeners for investigations on human accumulation and exposure. The total concentration of the seven PCB congeners (UNEP-7) proposed to the United Nations Environment Programme (UNEP) by Muir and Morita was about 50% of the total concentration of all PCB congeners, and UNEP-30 was about 80%. The seven main congeners in the blood (MCB-7) showed a value that was about 60%, and MCB-30 showed a value that was about 90%. Determinations with the main congeners in the blood showed a correlation of r = 0.990 or more between the main eight congeners (MCB-7 plus #74) and the total PCB concentration for all congeners. The results suggest that, although total PCB concentration can be effectively estimated from the main seven congeners, the main eight congeners would be preferable, and that the use of these congeners in the simple mass screening method would be effective for populations in areas uncontaminated by PCBs.     

Possible involvement of the glycocalyx in the ichthyotoxicity of Chattonella marina (Raphidophyceae): immunological approach using antiserum against cell surface structures of the flagellate

Although the ichthyotoxic mechanism of Chattonella marina is still unknown, several lines of evidence suggest that the reactive oxygen species (ROS), such as superoxide anion (O₂^-), hydrogen peroxide (H₂O₂)_, and hydroxyl radical (·OH), produced by C. marina are involved in the mortality of fish exposed to this flagellate. Recently, we found that the cell-free supernatant prepared from C. marina, which is considered to contain the glycocalyx, showed NADPH-dependent O₂^- generation. In this study, we prepared antiserum against the crude glycocalyx of C. marina. Using indirect immunofluorescence, it was confirmed that the antiserum specifically reacted with C. marina cells. In addition to C. marina, the antiserum also reacted with other raphidophycean flagellates such as Heterosigma akashiwo, Olisthodiscus luteus, and Fibrocapsa japonica, whereas no reactivity was observed against six other flagellate species tested. These results suggest that raphidophycean flagellates have common epitopes recognized by the antiserum. Interestingly, immunohistochemical analysis of paraformaldehyde-fixed gill lamellae from yellowtail exposed to C. marina revealed that the antiserum stained the surface of gill lamellae, while no such staining pattern was observed in control gill lamellae. These results suggest that the glycocalyx may be discharged when C. marina cells are inhaled into the fishes' mouths and then come into contact with the gill surface. Based on the present results, together with our previous findings, we propose that continuous accumulation of the discharged glycocalyx on the gill surface occurs during C. marina exposure, which may be responsible for the ROS-mediated severe gill tissue damage leading to fish death.     

Lectin-induced enhancement of superoxide anion production by red tide phytoplankton

Chattonella marina, a raphidophycean flagellate, is a highly toxic red tide phytoplankton which causes severe damage to fish farming. Recent studies demonstrated that Chattonella spp. continuously release superoxide anions (O₂ ⁻) while they are living. Heterosigma akashiwo, another raphidophycean flagellate, also produces O₂ ⁻. In the present study, we found that lectins such as concanavalin A (Con A), wheat germ agglutinin (WGA), and castor bean hemagglutinin (CBH) stimulated  C. marina and H. akashiwo to generate enhanced amounts of O₂ ⁻ in a concentration-dependent manner. The lectin-specific sugars potently inhibited the lectin-induced increase of O₂ ⁻ production, suggesting that the effects of lectins are mediated mainly through the interaction of these lectins with carbohydrate moiety present on the flagellate cell surface. In contrast to the potent ability of native Con A (tetravalent), succinylated Con A (divalent) showed only a slight stimulative effect on these flagellates. O₂ ⁻ production was totally inhibited by treatment with proteinase K for 30 min, without affecting the viabilities of flagellates. These results suggest that cell-surface redox enzymes may be involved in O₂ ⁻ production, and such enzymes are responsible for the lectin-stimulation. Received: 21 August 1997 / Accepted: 8 January 1998     

Rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar

The rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar was carried out in a hydrogen atmosphere at 1073 K and 973 K. The assumed oligomers were partially pyrolyzed epoxy resin with biomass tar as solvent for the resin. The product distributions obtained from rapid hydropyrolysis of phenol and bisphenol-A are shown. We also discuss the effects of reaction temperature and hydrogen partial pressure on the product yield. In particular, more phenol was produced from bisphenol-A at 973 K than at 1073 K. The yield of methane, which was the final hydropyrolysis product, increased with increasing hydrogen partial pressure, whereas benzene and phenol were believed to behave as intermediate products in the hydropyrolysis reaction. The results suggest that phenol could be obtained with high selectivity from tar by optimizing the reaction conditions.     

α1-Microglobulin levels and correlation with cadmium and other metals in urine of non-smoking women among general populations in Japan

The present study was initiated to examine urinary α₁-microglobulin (α₁-MG-U) levels among non-smoking women in the general population in Japan. A previously established database on spot urine samples from adult woman volunteers in 10 non-polluted areas all over Japan was re-examined. The data examined were on α₁-MG-U, cadmium, calcium, magnesium and zinc levels in urine (Cd-U, Ca-U, Mg-U and Zn-U, respectively), urinary creatinine (CR or cr), urine specific gravity (SG or sg), smoking habits and age. Thus, 8975 never-smoking women were selected for statistical analyses. The grand geometric mean (GM) for α₁-MG-U among the population was 2.1?mg/L or 2.5?mg/g?cr, depending on the correction for urine density. It was 1.1?µg/L or 1.3?µg/g?cr for GM Cd-U. The inter-area difference in α₁-MG-U was <1.5?mg/g?cr or <0.7?mg/L; the area with the highest or lowest GM Cd-U was not always highest or lowest in GM α₁-MG-U. The correlation coefficient (0.53) between log?Cd-U and log?α₁-MG-U (both without urine density correction) became substantially smaller when the analyte levels were corrected for CR (0.25) or SG (0.26). In multiple regression analysis, the power of influence of the five independent variables (log?Cd-U, Ca-U, Mg-U, Zn-U and age) in combination was small (R ²?≦?0.13). In contrast, logistic regression analysis suggested that α₁-MG-U might be elevated as a function of an increase in Cd-U, depending on the cut-off values. Discussion was made on dose (Cd-U_cr) and response (α₁-MG-U_cr) relationship based on information available in literatures to show that the increment in α₁-MG-U_cr per Cd-U_cr was much greater when Cd-U_cr was large, e.g., in excess of 10?µg/g?cr.     

Economic evaluation of sewage treatment processes in India

This paper evaluates the total annual cost including capital and operation and maintenance (O&M) costs for the up-flow anaerobic sludge blanket (UASB) and waste stabilization pond (WSP) systems operated in India. It also compares UASB and WSP systems with the activated sludge process (ASP) and biological aerated filter (BAF) systems in terms of total annual cost and chemical oxygen demand (COD) removal cost by assuming various annual interest rates and land prices. It was found that the relationship between capital and O&M costs per unit size of a UASB or WSP system and its treatment capacity can be established by a first-order equation. The relation between the cost of organic removal and capital or O&M cost for various sewage treatment systems at various annual interest rates revealed that, for the Indian context, UASB could be the most suitable option in terms of expenses and treatment efficiency.     

Production of biologically safe digested manure for land application by a full-scale biogas plant with heat-inactivation

Inactivation of indigenous indicator micro-organisms such as faecal coliforms, coliphages, and faecal streptococci was investigated in a full-scale biogas plant that mainly digested cow manure. The biogas plant consisted principally of a feed reservoir, fermentation tank (37 degrees C), heat-inactivation process (70 degrees C), and five reservoirs for the heat-inactivated, digested manure that was used by a local livestock farmer as liquid fertilizer. Although all the indicators tended to exhibit stepwise decreases with each stage of treatment, coliphages were found to be more capable of surviving than faecal coliforms and faecal streptococci under mesophilic anaerobic conditions as well as high temperature conditions (heat-inactivation at 70 degrees C). Liquid fertilizer produced at the biogas plant had faecal coliform densities less than the stipulations of the US EPA 40 CFR 503 Class A limits. Heat-inactivation tests indicated that although coliphages exhibited more tolerance than other bacterial indicators between 37 and 70 degrees C, they were more sensitive to continuous temperature increase than faecal coliforms and faecal streptococci.     

Separation of plastic mixtures using liquid-fluidized bed technology

Separation of heavier-than-water plastic mixtures had been investigated via the fluidization of their packed beds induced by an upward flow of water. The samples examined were resin pellets and crushed plastic products including PVC, PET and PBT. On the onset of a flow, a mixed bed was swelled to the state of fluidization and separated into layers of respective resins depending on their density. The effects of the flow rate, an amount of the samples and their density difference were examined on the separation of resin pellets. Under an appropriate condition, the process was completed within a few minutes, and satisfactory separation was attained when the density difference of the samples exceeded 0.05 g cm-3. By using a column equipped with several sample outlets sorted resins could be recovered with their purity intact by withdrawing each layer successively from above through a suitable outlet. Multi-stage separation was also found to be effective in treating close-density samples. Compared with uniform-sized resin pellets, size distribution of crushed plastic samples deteriorated the separation to some extent.