Anaerobic biodegradation of biphenyl in various paddy soils and river sediment

The anaerobic degradation of biphenyl was investigated in four uncontaminated Japanese paddy soils and one river sediment sample contaminated with benzene and chlorinated aliphatics. Two of the paddy soils and the sediment were capable of degrading biphenyl anaerobically without any additional medium or electron acceptors. The half-lives of biphenyl biodegradation in the three samples were 212 d in the Kuridashi soil, 327 d in the Kamajima soil, and 429 d in the river sediment. The Kuridashi soil metabolized 1+/-0.3% of [U-14C]-biphenyl into CO2 and 5+/-2% into water-soluble metabolites after 45 d of incubation. Submerged conditions, which result in lower nitrate and iron oxide contents, and neutral pH, appeared to be the common properties among the samples that influenced their degradation capacities. The addition of 10mM sulfate and 20mM Fe(III) as electron acceptors did not enhance the biphenyl degradation rate, whereas 10mM nitrate completely inhibited biphenyl degradation. The addition of different electron donors (lactate, acetate, or pyruvate) slightly slowed the degradation. Molybdate (an inhibitor of sulfate-reducing bacteria) had an inhibitory effect on biphenyl biodegradation, but bromoethanesulfonic acid (an inhibitor of methanogens) did not. Most biphenyl degradation was observed when only water was added, with no other electron acceptors or donors. These results suggest that sulfate-reducing bacteria and fermentative microbial populations play important roles in anaerobic biphenyl biodegradation in paddy soil.     

Assessment of the Water Quality of Troia for the Multipurpose Usages

The aim of this study was to determine the origin and quality of waters in Troia. For this purpose total of 25 water samples including 2 springs, 14 surfaces and 9 groundwaters, were collected at eight different times. Global positioning system (GPS) was used to determine to coordinates of sampling points. The concentration of 6 minor elements (B, Cu, F, Fe, Pb and Zn), 9 major anions and cations (Na(+), Ca(2+), K(+), Mg(2+), SO(4)(2-), PO(4)(3-), HCO(3)(-), Cl(-) and, CO(3)(2-)) were determined by spectrometric, colorimetric and volumetric methods. Water pH, EC, DO, ORP and TDS were measured in situ using probes. The data showed that the concentrations of most of minor elements were below the EPA and TSE limits except Pb which ranged between 0.001 and 4.832 mg L(-1). Statistically significant relationships (P<0.01 and r>0.70) were observed between Fe and Cu, Cu and K(+), Cu and Ca(2+), B and Na(+), Na(+) and K(+). Assessing the water based on irrigation using Wilcox model showed that some well waters were not suitable for irrigation. Troia water was found to be highly corrosive and the average corrosion coefficients varied from 0.5 to 4.6. According to the Piper and Schoeller diagrams results, the water in Troia was classified as mixed water type.     

Preparation and Biodegradation of Starch/Polycaprolactone Films

Starch granules were modified with trisodium trimetaphosphate (TSTP) and characterized by P³¹-NMR, FTIR and DSC. Seventy-micron films were prepared from modified starch and polycaprolactone blends by solvent casting technique. Three different types of films—PCL (100% polycaprolactone), MOD-ST/PCL (50% modified starch and 50% polycaprolactone blend) and NONMOD-ST/PCL (50% nonmodified starch and 50% polycaprolactone blends)—were prepared, and their thermal, mechanical, and morphologic properties were investigated to show the increased performance of PCL with the addition of starch and also the effect of modification. It was observed that with the addition of starch the Young's modulus of polycaprolactone was increased and became less ductile, whereas tensile strength and elongation at break values decreased. Biodegradation of these films was inspected under different aerobic environments with the presence of Pseudomonas putida, activated sludge, and compost. It was observed that whereas P. putida had almost no effect on degradation during 90 days, with the presence of activated sludge, considerable deformation of films was observed even in the first 7 days of degradation. In a compost environment, degradation was even faster, and all polymer films were broken into pieces within first 7 days of degradation and no film remained after 15 days.     

Comparison of trace element accumulation in Baikal seals (Pusa sibirica), Caspian seals (Pusa caspica) and northern fur seals (Callorhinus ursinus)

Concentrations of 18 trace elements (V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sb, Cs, Hg, Tl and Pb) were determined in liver, kidney, muscle and hair of Baikal seals, Caspian seals and northern fur seals. All the three species showed the highest concentrations of Hg, V, Mn, Se and Ag in liver, Cd, Co and Tl in kidney, and Cs in muscle among the soft tissues examined. The highest burdens of Zn, Rb and Cs were observed in muscle, Mo and Ag in liver, and Sb and Pb in hair in all the three species. Concentrations of non-essential elements, Rb, Cd, Cs and Hg, showed significant positive correlations among liver, kidney and muscle, whereas correlation coefficients for essential elements, Mn, Co, Cu, Zn and Se, between the three tissues were generally low for all the species, suggesting that homeostasis controls the concentrations of essential elements but not the non-essential elements in the tissues of these animals. Significant age-dependent increase was found in the concentrations of V, Se and Ag in liver and Hg in liver and kidney of all the three species. Hair concentrations showed significant positive correlations with Zn levels in liver and kidney and Hg in muscle for Caspian seals, Hg in liver and kidney for Baikal seals, and Pb in liver for northern fur seals. Furthermore, regression analysis using the data in the present study and in the literature showed significant positive correlations between Hg levels in hair, and liver, kidney and muscle for various species of pinnipeds. These results indicate the possibility of using hair samples for monitoring these trace elements in pinnipeds.     

Persistent organochlorine residues in northern fur seal from the Pacific coast of Japan since 1971

The present study was conducted to determine the residue levels of persistent organochlorines such as PCB homologues, DDT and its metabolites, and HCH isomers in the ventral blubber of female northern fur seal (Callorhinus ursinus) collected off Sanriku, the Pacific coast of northern Japan, since 1971. Among the organochlorines examined, the concentrations of PCBs and DDTs were found to be high in all samples. The residue levels of these two contaminants showed a drastic reduction following maturity and then a slight increase after the retirement from pregnancy/menopause. Temporal variation of PCB and DDT residues showed maximum levels around 1976 and then decreased, whereas HCH residue levels revealed a very slow declining pattern. Considering the concentrations and compositions of the residues, the northern fur seal is likely to be exposed to organochlorine contamination deriving from global terms. In this context, continuous contamination has been foreseen with regard to PCB and HCH residues. The pattern of organochlorine residues indicated that the northern fur seal has higher metabolic capacity than Dall's porpoise, while it is comparable to those of larga seal and Steller sea lion.     

Effects of leachant temperature and pH on leachability of metals from fly ash. A case study: Can thermal power plant, province of Canakkale, Turkey

Lignite powered electric generation plants result in increasing environmental problems associated with gaseous emissions and the disposal of ash residues. Especially, low quality coals with high ash content cause enormous quantities of both gaseous and solid fly ash emissions. The main problem is related to the disposal of fly ash, which, in many cases, contains heavy metals. It is known that toxic trace metals may leach when fly ash is in contact with water. In this study, fly ash samples obtained from the thermal power plant in the town of Can in Turkey were investigated for leachability of metals under different acidic and temperature conditions. The experimental results show that a decrease in pH of the leachant favors the extraction of metal ions from fly ash. A significant increase in the extraction of arsenic, cadmium, chromium, zinc, lead, mercury, and selenium ions from the ash is attributed to the instability of the mineral phases. These heavy metals concentrations increase with respect to increasing acidic conditions and temperature. Peak concentrations, in general, were found at around 30°C.     

How the origin of fresh household waste affects its ability to be biodegraded: An assessment using basic tools and its application to the city of Kara in Togo

Waste biodegradation has been largely investigated in the literature by using conventional tests like the BMP test and the respirometric test, whereas only few studies deal with the use of leaching tests in combination with biological activity measurements. Consequently, this study used an improved leaching test to evaluate the biodegradability of two deposits of fresh household waste from the city of Kara in Togo. The first deposit came from households in neighborhoods located in the outskirts of the city and the second consisted of fresh waste, mainly composed of business waste and household waste, collected in the urban center and aimed at being deposited in the landfill. A physicochemical characterization of the two deposits completed the leaching test. The biological activity was monitored by measuring O₂ consumption and CO₂ production. pH, DOC/OM, VFA/DOC ratios and the SUVA index was measured in the leaching juice to assess both the state of degradation of the waste in the deposits and the ability of the organic matter to be mobilized quickly and to be easily assimilated by microorganisms. The biodegradability of waste from the city of Kara correlated with their origin even though the physical characteristics of the two deposits studied differed greatly.     

Transformation of diphenylarsinic acid in agricultural soils

We investigated the transformation and fate of diphenylarsinic acid (DPAA) during incubation in two types of soils (Entisol and Andisol) under aerobic and anaerobic conditions. Under anaerobic conditions only, DPAA was transformed into methyldiphenylarsine oxide by methylation. Under both aerobic and anaerobic conditions, DPAA was degraded to phenylarsonic acid by dephenylation, and phenylarsonic acid was subsequently methylated to form methylphenylarsinic acid and dimethylphenylarsine oxide. The degradation of DPAA in the Andisol was less extensive than in the Entisol. In autoclaved soil under anaerobic conditions, DPAA underwent little degradation during the 24-wk incubation. In unautoclaved soils, the concentration of DPAA in soil clearly decreased after 24 wk of incubation, indicating that DPAA degradation was driven by microbial activity.