Lysis of cyanobacteria with volatile organic compounds

One of bacteria collected from Lake Sagami, Japan, Brevibacillus sp., was found to have a lytic activity of cyanobacteria, but did not produce active compounds. Instead, the co-culturing of Microcystis with the Brevibacillus sp. enhanced the production of two volatile compounds, beta-cyclocitral and 3-methyl-1-butanol, and the former had a characteristic lytic activity. It was confirmed that these volatile compounds were derived from the cyanobacteria themselves. beta-Ionone, geosmin and 2-methylisoborneol derived from cyanobacteria and similar volatile compounds, terpenoids, produced by plants also had a lytic activity. The minimum inhibitory concentration values of the cyanobacterial metabolites were estimated to be higher than those of compounds from plants except for a few compounds. Among them, beta-cyclocitral only produced a characteristic color change of culture broth from green to blue. This color change is similar to the phenomenon observed when a sudden decline in growth of cyanobacteria begins in a natural environment.     

Formation of PCDDs and PCDFs during the combustion of polyvinylidene chloride and other polymers in the presence of HCl

PVDC and three non-chlorinated polymers (PP, PET, and PA) were incinerated at 700-850 degrees C in a laboratory-scale quartz tubular furnace in the presence of HCl (ca. 500 ppm congruent with 0.8 mg/l), and the gas-phase formation of PCDD/Fs, their putative precursors and their homologue profiles were investigated. The addition of HCl had little or no apparent effect on the level of PCDD/Fs formation during PVDC combustion, and their homologue profiles were quite different from those of the three non-chlorinated polymers. With PVDC, O8CDD and particularly O8CDF were by far most prevalent, apparently as a result of the selective formation of the precursors. With each of the three non-chlorinated polymers, combustion at 800 degrees C or higher in the presence of HCl resulted in PCDD/Fs formation at levels equaling or exceeding those observed with PVDC. In trials made with one of them (PP) under the same conditions but using a large polymer sample (100 mg vs 20 mg in all other trials), the level of PCDD/Fs formation was far higher than with the smaller polymer samples, and thus demonstrated the importance of appropriate combustion conditions for polymer incineration.     

Removal of heavy metals in rinsing wastewater from plating factory by adsorption with economical viable materials

The removal of heavy metals from plating factory wastewater with economical materials was investigated by the column method. Montmorillonite, kaolin, tobermorite, magnetite, silica gel and alumina were used as the economical adsorbents to wastewater containing Cd(II), Cr(VI), Cu(II) and Pb(II). This removal method of heavy metals proved highly effective as removal efficiency tended to increase with increasing pH and decrease with increasing metal concentration. The removal percentages by adsorption onto montmorillonite, tobermorite, magnetite, and silica gel showed high values for all metals. From the results for the heat of adsorption, the adsorption process in the present study might be chemisorption. The proposed method was successfully applied to the removal of Cd(II), Cr(VI) and Cu(II) in rinsing wastewater from plating factory in Nagoya City, Aichi Prefecture, Japan. Since the economical adsorbents used can be obtained commercially because they are easily synthesized, the wastewater treatment system developed is rapid, simple and cheap for the removal of heavy metals.     

Assessment of human exposure to PCDDs,PCDFs and Co-PCBs using hair as a human pollution indicator sample I: Development of analytical method for human hair and evaluation for exposure assessment

Dioxins including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and co-planar polychlorinated biphenyls (Co-PCBs) are highly toxic. Even at environmental pollution levels, they cause hormonal damage in women, and they have been shown to induce immunosuppression and genital function damage in humans. In this study, a new method using isotope dilution was established to detect PCDDs, PCDFs and Co-PCBs in human hair. This method, comprised of washing and cutting of hair, alkaline decomposition, hexane extraction, multilayer silica gel column chromatography, high performance liquid chromatography with a porous graphite carbon column and analysis by high resolution gas chromatography/high resolution mass spectrometry, enabled us to analyze PCDDs, PCDFs and Co-PCBs at trace levels of less than pg/g with good reproducibility. In addition, there was a correlation between some isomers in human hair and blood collected from identical donors. Human hair analysis is useful to evaluate human risk assessment including that due to environmental pollution.     

Enhancement in fecal excretion of dioxin isomer in mice by several dietary fibers

The effect of increased nutrients (protein, lipid, vitamins and minerals) on dioxin-induced toxic manifestations such as immune suppression, hepatic hypertrophy, splenic atrophy and enzyme induction was investigated in mice after oral administration of 1,2,3,4,7,8-HxCDD (HxCDD) as one of a representative compound of dioxin isomers. Consequently, it appeared that increased minerals and vitamins in the diet prevented immune suppression by HxCDD. In addition, to clarify the additive effect of nutrients and the ability to hasten the excretion of dioxins by dietary fiber, the adsorbing of dioxins by 16 dietary fibers was investigated by in vitro experiment. Among 16 dietary fibers, locust bean gum, pectin, alginic acid, guar gum, chitin and cellulose were effective in binding dioxin isomers. These dietary fibers also enhanced the fecal excretion of HxCDD in mice.     

Endocrine disrupter nonylphenol and bisphenol A contamination in Okinawa and Ishigaki Islands, Japan--within coral reefs and adjacent river mouths

Certain chemicals possess the potential to modulate endocrine systems, and thereby interfere with reproduction and developmental processes in the wild. We analyzed endocrine disrupters nonylphenol (NP) and bisphenol A (BPA) levels at various sites in Okinawa and Ishigaki Islands, Japan. River-water samples showed undetectable to low concentrations of NP and BPA at most of the sites investigated. However, an appreciable amount of BPA was detected in sediments at one coral reef site. In addition, significant numbers of river sediment samples showed appreciable amounts of NP and BPA. Most of the sampling sites for this study are located within a distance of 1 km from the coral reefs, which are under influence of river-waters to a variable extent. Therefore, influence of endocrine disrupters may have already begun on adjacent coral reefs. Both endocrine disrupters were positively correlated with human population densities, but not with the contents of red soil generated by farm land reformation. Therefore, it is concluded that NP and BPA pollution is a consequence of human waste discharge, both domestic and industrial, and not by agricultural activities.     

Molecular phylogeny of vestimentiferans collected around Japan, revealed by the nucleotide sequences of mitochondrial DNA

The phylogenetic relationships among local populations of undescribed vestimentiferan species that belong to the genera Lamellibrachia and Escarpia and had been collected at six sites around Japan were analyzed on the basis of the partial (1023 bp) nucleotide sequences of the mitochondrial gene for cytochrome oxidase I (COI), using a pogonophoran and a polychaete as outgroups. The identical amino acid sequence was deduced from the nucleotide sequence obtained from each of the vestimentiferans analyzed. The strong similarity among deduced amino acid sequences of COI suggested a close relationship between vestimentiferans and pogonophorans. On the basis of the phylogenetic relationships, the analyzed vestimentiferan populations were classified tentatively as five species. The genetic differentiation of vestimentiferans was suggested to occur bathymetrically as well as being a consequence of horizontal segregation. Two of these tentatively identified species inhabit both a hydrothermal area and a cold seep area, as is the case for some species of bivalves that belong to the genera Bathymodiolus and Calyptogena. Received: 28 August 1996 / Accepted: 2 October 1996     

Degradation of Reactive Yellow 86 with photo-Fenton process driven by solar light

The decolorization of Reactive Yellow 86(RY 86),one of reactive azo dyes,was investigated in the presence of Fenton reagent under solar light irradiation.The decolorization rate was strongly influenced by pH,initial concentrations of H 2 O 2 and Fe(II),and so on.An initial concentration of 40 mg/L was decolored more than 90% after 20 min under optimum conditions.The activation energy of the solar photo-Fenton reaction was 1.50 kJ/mol for RY 86 in the temperature range of 10-60°C.In the kinetic study,the rate constant of RY 86 with OH· radicals could be estimated to be 1.7 × 10 10 L/(mol·sec).The decolorization efficiency of RY 86 under solar light irradiation was comparable to the artificial light irradiation.The decrease of TOC as a result of mineralization of RY 86 was observed during photo-Fenton process.The rate of RY 86 mineralization was about 83% under UV irradiation after 24 hr.The formation of chloride,sulfate,nitrate and ammonium ions as end-products was observed during the photocatalytic process.The decomposition of RY 86 gave two kinds of intermediate products.The degradation mechanism of RY 86 was proposed on the base of the identified intermediates.     

Phylogenetic relationships among species of Calyptogena (Bivalvia: Vesicomyidae) collected around Japan revealed by nucleotide sequences of mitochondrial genes

Phylogenetic relationships among the seven species of deep-sea giant clams Calyptogena (Bivalvia: Vesicomyidae) collected around Japan were examined using parts of nucleotide sequences of mitochondrial genes for cytochrome oxidase I (COI) and cytochrome oxidase III (COIII) and the encoded amino acid sequences. The seven species were C. soyoae (Sagami Bay), C. fausta (Suruga Bay), C. kaikoi (Nankai Trough), C. nautilei (Nankai Trough), C. phaseoliformis (Japan Trench), C. solidissima (Minami-Ensei Knoll, Okinawa Trough) and Calyptogena sp. (Iheya Ridge, Okinawa Trough). A clear phylogenetic split was observed between one group of three species (C. kaikoi, C. phaseoliformis and C. fausta) and the remaining species. This clustering corresponds to the two previously described subgenera within the genus Calyptogena (Calyptogean and Ectenagena) with the exception of the placement of C. nautilei, which had been placed in the subgenus Ectenagena. Genetic distances between two haplotypes of C. soyoae were 0.043 for the COI region and 0.055 for the COIII region, and three amino acid substitutions were detected with the COIII region. Calyptogena sp. from the Iheya Ridge could be distinguished from one of the two haplotypes (type A) of C. soyoae by only a single nucleotide substitution, a result that suggests that Calyptogena sp. of the Iheya Ridge diverged from C. soyoae after the two haplotypes had diverged, and it is now isolated from C. soyoae in Sagami Bay.     

Occurrence of co-planar polybrominated/chlorinated biphenyls (PXBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk of women from Spain

In this study, for the first time, levels and accumulation profiles of eight currently available polybrominated/chlorinated biphenyl congeners (PXBs; XB-77, -105, -118, -126A, -126B, -126C, -156 and -169, named according to IUPAC nomenclature) in human breast milk collected form Spanish women in 2005 were reported. Concentrations and congener specific profiles of polychlorinated biphenyls (PCBs), including co-planar PCBs, (co-PCBs) and polybrominated diphenyl ethers (PBDEs) were also reported.A concentration of 0.45 pg g⁻¹ lipid weight was found for total PXBs, and arithmetic mean concentrations of 125, 25 and 5.5 ng g⁻¹ lipid weight were determined for total PCBs, co-PCBs and total PBDEs respectively. Detectable levels of all congeners investigated, except CB-123 and XB-169 were found. Levels of PCBs were similar to those found in Spanish samples collected after 2000, and lower than those obtained before 2000. CB-138, -153 and -180 were the predominant PCB congeners. PBDE levels, dominated by BDE-47, -99, -100 and -209, were lower than PCB levels. PXB concentrations were the lowest, with XB-156 being the most abundant. The concentration levels of PCBs and PBDEs found in this study were in the same range as those from other European countries. Levels of PXBs were much lower than published values determined in Japan which were the only data found in the literature.