Biodegradation of nonylphenol in soil

We investigated the effects of various factors (brij 30, brij 35, yeast extract, hydrogen peroxide and compost) on the aerobic degradation of nonylphenol (NP) in soil and characterized the structure of the microbial community in that soil. Residues of NP were measured using gas chromatography-mass spectrometry (GC-MS) and a change of microbial communities was demonstrated using denaturing gradient gel electrophoresis (DGGE). The results showed that Taichung sandy clay loam had higher NP degradation rate than Kaoshiung silty clay. The addition of compost, yeast extract (0.5 mg/l), brij 30 (55 microM), or brij 35 (91 microM) enhanced NP degradation, while the addition of hydrogen peroxide (1.0 mg/l) inhibited its degradation. We also found that the addition of various substrates changed the microbial community in the soils. Cytophaga sp. and Ochrobactrum sp. were constantly dominant bacteria under various conditions in the soil.     

Determination of polybrominated diphenyl ethers in soil and sediment from an electronic waste recycling facility

In this study samples of ten species of fish were analyzed for concentrations of organochlorine pesticides, PCBs and heavy metals (Pb, Cd, and Cu). Fish were captured using electric fishing on ten sites along the Dr?me river (Rh?ne-Alpes region). Quantitative determination of the organochlorine and PCBs compounds was performed by gas chromatography-electron-capture detection (GC-ECD). The concentrations of heavy metals were determined by atomic absorption spectrophotometry. Samples contained detectable concentrations of lindane, PCBs, and heavy metals but at concentrations below the maximum residue limit (MRL). Non-parametric statistical analysis was performed to distinguish groups of sites with different levels of contamination. PCBs concentrations increased along the river with four groups of sites significantly different from each other. Cadmium concentrations were below the MRL. Lead contamination showed two groups significantly different and a repartition similar to PCBs. Copper contamination was correlated with the localization of vineyards. We assessed the potential effects of contamination the otter (Lutra lutra). The concentrations of all pollutants analyzed in fish sampled in this study are lower than the threshold values described in literature. The Dr?me river is relatively unpolluted river, and the establishment of otter populations should not be affected by pollution.     

Analyzing the uncorrected error of dilution water demand for the dilution biochemical oxygen demand method.

Dilution water demand (DWD) can cause a positive error when the dilution biochemical oxygen demand (BOD) method is used. Dilution water demand may be attributed to oxidation of organic impurities in the dilution water and nitrification of ammonia added as a nutrient. To minimize the error associated with these sources, the standard BOD method requires that DWD be less than 0.2 mg/L in 5 days and does not allow correction for DWD when calculating test results. This study derives a set of theoretical equations to analyze the uncorrected errors with and without seeding. The authors concluded that DWD can be completely corrected if seeded dilution water is used for the sample dilution. When seeding individual bottles, the uncorrected error approaches 8.3 to approximately 8.8% at a 5-day depletion of 2 mg/L for a typical secondary effluent. Tests without seeding show an almost 1% higher uncorrected error than seeded tests. The analysis also suggests that these errors can be effectively reduced to less than 3% when the 5-day depletion approaches 6 mg/L. even for 5-day biochemical oxygen demand concentrations exceeding I x 10(4) mg/L. Further analysis indicates that, if not inhibited, the ammonium added to dilution water as a nutrient may contribute additional error due to nitrification.     

Modeling VOCs adsorption onto activated carbon

The activated carbon adsorption process is affected by the characteristics of adsorbent, adsorbate and environmental conditions. In this study, both adsorption and desorption processes are assumed to occur simultaneously and a numerical model was developed with a non-linear driving force in conjunction with the Langmuir model for predicting the overall adsorption process. The numerical model provides both adsorption and desorption rate constants and activation energies. The resultant equilibrium constants are of the same order of magnitude as reported by other studies. Results show that the model could well predict the adsorption isotherms and breakthrough curves under various conditions.     

Diffusion of hydrogen sulfide and methyl mercaptan onto microporous alkaline activated carbon

Activated carbon kinetic studies show that both H2S and CH3SH yielded pore diffusion coefficients from 10(-6) to 10(-8) cm2/s. Results indicated that pore structures could influence effective diffusivity. Under the same adsorbate concentration, CH3SH exhibited a greater effective pore diffusion coefficient than H2S. This may be attributed to the fact that CH3SH has both polar (-SH) and non-polar (-CH3) functional groups and dissolves into water easier, thus providing more attraction for the activated carbon surface. In addition, the saturation vapor pressure of CH3SH is lower than that of H2S. Therefore, CH3SH is easier to adsorb onto activated carbon than H2S.     

Adsorption/desorption properties of copper ions on the surface of iron-coated sand using BET and EDAX analyses

This study was conducted to develop a heating process for coating hydrated iron oxide on the sand surface to utilise the adsorbent properties of the coating and the filtration properties of the sand. BET and scanning electron microscope (SEM) analyses were used to investigate the surface properties of the coated layer. An energy dispersive X-ray (EDAX) technique of analysis was used for characterising metal adsorption sites on the iron-coated sand surface. The results indicated that the iron-coated sand had more micropores and higher specific surface area because of the attachment of iron oxide. Copper ions could penetrate into the micropores and mesopores of iron oxide on sand surface, and the regeneration of the iron-coated sand could be achieved by soaking with pH = 3.0 acid solution. Besides, the results of EDAX analysis showed that copper ions were chemisorbed on the surface of iron-coated sand. Results of the study developed an innovative technology for coating iron oxide on sand surface for the treatment of heavy metal in water.     

Kinetics of radiocesium released from contaminated soil by fertilizer solutions

(137)Cs is one of the major artificial radionuclides found in environments; but the mechanisms behind fertilizer-induced (137)Cs desorption from soil remain unknown. This study aimed to investigate the kinetics and mechanisms underlying the various cations and anions that cause Cs release from soil under acidic conditions. NH(4)H(2)PO(4) (1M), 0.5M (NH(4))(2)SO(4), 1M NH(4)Cl, 1M KCl or 1M NaCl solutions were added to (137)Cs-contaminated soil. The power function model well described the short term (137)Cs desorption with the solutions. The rate coefficients for (137)Cs release from soil in NH(4)H(2)PO(4), (NH(4))(2)SO(4), NH(4)Cl, and KCl solutions were 7.7, 7.3, 6.8, and 6.1 times higher than the rate observed in a NaCl solution, respectively. The NH(4)H(2)PO(4) and (NH(4))(2)SO(4) solutions induced significantly greater (137)Cs release from the contaminated soil than the NH(4)Cl, KCl and NaCl solutions. After four times repeated extractions with the fertilizer solutions, the total amount of (137)Cs extracted by (NH(4))(2)SO(4) and NH(4)Cl solutions reached equilibrium, while that extracted using an NH(4)H(2)PO(4) solution continued to increase. The combined effect of phosphate and protons was the major mechanism behind (137)Cs release from contaminated soils, when an NH(4)H(2)PO(4) solution was used.     

Identification of a new Irgarol-1051 related s-triazine species in coastal waters

A previously unknown s-triazine species present in commercially available Irgarol-1051, a booster biocide additive in copper-based antifouling paints for the replacement of organotin-based antifoulants, has been identified in the coastal aquatic environment. After careful isolation, purification and characterization by high resolution MS-MS and (1)H NMR, the molecular structure of that unknown species is found to be N,N'-di-tert-butyl-6-methylthiol-s-triazine-2,4-diamine (designated as M3). Levels of Irgarol-1051, its major degradation product (M1) and the newly identified M3 in the coastal waters of Hong Kong, one of the world's busiest ports located in the southern coast of China, were monitored by SPME-GC-MS and SPME-GC-FID. Water samples from five locations within Hong Kong waters were analysed and the levels of Irgarol-1051, M1 and M3 were found to be 0.1-1.6 microg l(-1), 36.8-259.0 microg l(-1) and 0.03-0.39 microg l(-1), respectively. Our results indicate that M3 is relatively stable against photo- and bio-degradation and may pose considerable risk to primary producer communities in the coastal marine environment.     

Fix-Neyman model of illness-death processes

The concept of the life table originated in longevity studies of man, where it was always presented as a subject peculiar to public health, demography, and actuarial science. As a result, its development has not received sufficient attention in the field of statistics. Actually, the problems of mortality studies are similar to those of reliability theory and life testing, and they may be described in terms familiar to the statistically oriented mind. From a statistical point of view, human life is a random experiment and its outcome, survival or death, ss subject to chance. The life table systematically records the outcomes of many such experiments for a large number of individuals over a period of time. Thus, the quantities in the table are random variables subject to established statistical analysis. The purpose of this presentation is to discuss the life table from a statistical viewpoint.     

Biodegradation of nonylphenol in sewage sludge

We investigated the effects of various factors on the aerobic degradation of nonylphenol (NP) in sewage sludge. NP (5 mg/kg) degradation rate constants (k₁) calculated were 0.148 and 0.224 day⁻¹ for the batch experiment and the bioreactor experiment, respectively, and half-lives (t_1/2) were 4.7 and 3.1 days, respectively. The optimal pH value for NP degradation in sludge was 7.0 and the degradation rate was enhanced when the temperature was increased and when yeast extract (5 mg/l) and surfactants such as brij 30 or brij 35 (55 or 91 μM) were added. The addition of aluminum sulfate (200 mg/l) and hydrogen peroxide (1 mg/l) inhibited NP degradation within 28 days of incubation. Of the microorganism strains isolated from the sludge samples, we found that strain CT7 (identified as Bacillus sphaericus) manifested the best degrading ability.