Kazuho Inaba

Effects of salinity, pH and temperature on aqueous solubility of four organotin compounds

Abstract The aqueous solubility of four organotin compounds, such as tributyltin chloride (TBTCl), bis(tributyltin) oxide (TBTO), triphenyltin chloride (TPTCl) and bis(triphenyltin) oxide (TPTO) was determined at various salinity, pH and temperature. The solubility of these compounds decreased with increasing the salinity. It also changed at different pH and was minimum in the pH range of 6–8. The solubility at 10°C was about half of that at 25°C. The minimal solubility of TBTs and TPTs in artificial seawater at 25°C was 1.0 mg Sn 1 −1 at pH 6–8 and 0.3 mg Sn 1 −1 at pH 7–8 and in distilled water at 25°C was 15 mg Sn 1 −1 at pH 7–8 and 0.8 mg Sn 1 −1 at pH 7–8, respectively.

HPLC Determination of Linear Alkylbenzenesulfonate (LAS) in Aquatic Environment. Seasonal Changes in LAS Concentration in Polluted Lake Water and Sediment

Abstract An analytical method for linear alkylbenzenesulfonate (LAS) using HPLC was studied. It was found that the peaks of different LAS isomers with alkyl chain lengths between 11 and 14 could be separated by gradient elution with aqueous NaClO4 solution and acetonitrile. The pretreatment of the LAS in the environmental samples was studied and an easy-to-use method involving solvent extraction with 4-methyl-2-pentanone was developed. By using these techniques the concentrations of the different LAS analogues in environmental samples could be measured respectively. The method was used to determine LAS in the aquatic environment; and the seasonal changes of these chemicals were clearly observed.

Seasonal and longitudinal changes in copper and iron in surface water of shallow eutrophic Lake Kasumigaura, Japan

Abstract The concentrations of copper and iron in surface water of the eutrophic Lake Kasumigaura, the second largest lake in Japan, have been monitored at three sites monthly from April 1989 until March 1994. The metals were analyzed by a graphite furnace AAS after filtration with a 0.45-μm membrane filter. The concentrations of copper in the water were in the range 10 −9 to 5 × 10 −8 M and showed clear seasonal changes, being higher in summer and lower in winter. The concentrations of copper did not decrease on passage through the lake. The values of dissolved chemical oxygen demand (COD Mn ) showed a similar behavior, an interaction of copper in the lake water with organic matter was estimated. The concentration of copper in the lake became sometimes higher than the value of EC 50 for Microcystis , however, the metal forms stable complex species with organic matter and the toxic effect may be reduced. The concentrations of iron, on the other hand, showed wide variation, but no obvious seasonal change. The concentrations of iron decreased very markedly during flow of water through the lake.

Quantitative assessment of natural purification in wetland for linear alkylbenzenesulfonates

Abstract Natural purification in a small wetland (474 m 2 ) for linear alkylbenzenesulfonates (LAS) was assessed quantitatively and was found to involve adsorption on sediment particles and degradation with bacteria in the wetland. Temperature affected the amount of biodegradation but not adsorption. Consequently, biodegradation did not occur and LAS was decreased only by adsorption in winter in the present wetland. In the summer, decrease by biodegradation was larger than that of LAS in the inflow, and thus, LAS already adsorbed was also decreased. Natural purification is discussed from the standpoint of the carrying capacity of adsorption or biodegradation calculated from field data. It was concluded that the wetland could adsorb about 5 kg of LAS and could remove more than 20 kg of the chemical in a year while about 35 kg of LAS inflowed in a year.

DNA microarray mediated transcriptional profiling of Nitrosomonas europaea in response to linear alkylbenzene sulfonates

Linear alkylbenzene sulfonates (LAS) constitute, quantitatively, the most important group of synthetic surfactants used today. We studied the gene expression of Nitrosomonas europaea in response to LAS using a DNA microarray because ammonia-oxidizers are thought to be more sensitive to LAS than other microorganisms. Our objective was to elucidate which genes are expressed for N. europaea in response to LAS exposure. Microarray analysis and real-time PCR assay revealed that c. 30 genes were significantly expressed after LAS exposure, in particular genes associated with energy production and conversion. Our findings demonstrate that physical disruption of membrane structures, which contain enzymes associated with energy production and conversion, might be an important explanation for the high sensitivity of N. europaea to LAS exposure.

A method for behaviour analysis of synthetic chemicals in the aquatic environment using their adsorption constants. ‐ a study of linear alkylbenzenesulfonate in wetland –

Abstract An easy‐to‐use method for analyzing the behavior of synthetic chemicals in aquatic environments is proposed. The behavior of the chemicals can be analyzed by comparison of the ratio of the reduction constants for these chemicals obtained by field investigation and that of adsorption constants on the sediment particles obtained separately by laboratory experiments. By using the present method, the quality of the natural purification of linear alkylbenzenesulfonate in the wetland was considered. Analysis of the data suggested that biodegradation was temperature controlled with an “ON‐OFF”; switch operating at 6 to 9 °C.

Determination of Trace Levels of Polyoxyethylene-Type Nonionic Surfactants in Environmental Waters

Abstract An analytical method for polyoxyethylene-type nonionic surfactants is proposed. It was found that the surfactants are preconcentrated by solvent extraction with toluene and many coexisting substances such as LAS or humic acid are washed out at the same time. Those in the toluene can extract cobalt(II) from aqueous thiocyanate solution. By determination of the metal with spectrophotometry as 4-(2-pyridylazo-)-resorcinolato complex, the concentration of the surfactants can be measured. Use of toluene as the solvent is useful not only for the purification of the surfactants from many interferences but also for the easier treatment of waste solvents in comparison to i.e. halogenated organic solvents.

EFFECTS OF SEVERAL SURFACTANTS AND HIGH‐MOLECULAR‐WEIGHT ORGANIC COMPOUNDS ON DECOMPOSITION OF TRICHLOROETHYLENE WITH ZEROVALENT IRON POWDER

Abstract We investigated the effects of coexisting surfactants and high‐molecular‐weight organic compounds on the reductive dechlorination of trichloroethylene by zerovalent iron powder to determine whether these additives had utility as washing reagents for remediation of soil and groundwater pollution. During the dechlorination reaction, the amount of trichloroethylene decreased, and the formation of cis‐1,2‐dichloroethylene was observed. The decomposition of trichloroethylene was found to be first‐order with respect to the trichloroethylene and zerovalent iron concentrations when the solution contained no additives. The rates of decomposition of trichloroethylene in the presence of the additives were lower than the rate in the absence of the additives: the rate constant was reduced by a factor of 0.7 for the cationic surfactant cetyltrimethylammonium bromide; by a factor of 0.5 for the anionic surfactants sodium n‐dodecylbenzenesulfonate, sodium n‐dodecylsulfate, and sodium n‐dodecanesulfonate and for the high‐molecular‐weight organic compounds soluble starch, β‐cyclodextrin, and polyethyleneglycol 6000; and by a factor of 0.2 for sodium laurate and the nonionic surfactants Triton X‐100, Tween 20, Tween 60, Brij 35, and Brij 58. Comparison of the concentrations of the nonionic surfactants with their critical micellar concentrations indicated that the rate‐reducing effect of these additives was due to solubilization of trichloroethylene into the micellar phase. The adsorption of trichloroethylene onto the zerovalent iron surface was also affected by the presence of the additives. Thus, our results indicated that the changes in the decomposition rate of trichloroethylene were determined by several factors.

Effects of coexisting linear alkylbenzenesulfonates on migration behavior of trichloroethylene in porous media

Abstract The effect of coexistence of linear alkylbenzenesulfonates (LAS) on the migration behavior of trichloroethylene (TCE) was measured by porous column. It was observed that the migration of TCE occurs by different mechanisms at different LAS concentrations. When LAS was higher than its critical micelle concentration (CMC), TCE eluted by micellar solubilization. When LAS was lower than its CMC, TCE eluted as small droplets through a column which was packed with 0.8mm diameter of glass beads although it eluted only water saturation solubility when the column was packed with 140 mesh glass powder. From the observations, the effects of coexisting LAS on the migration of TCE were concluded to be: (i) solubilization of TCE into its micelle, and (ii) decrease of surface tension and granulation of TCE with emulsification. The former effect only occurred when the LAS concentration was higher than its CMC while the latter effect occurred even in the LAS concentration below its CMC.

Source and material balance of total organic halogen pollution in the Ayase River system, Japan

The total organic halogen (TOX) pollution in the highly polluted Ayase River system was investigated. Using the concentration of coexisting linear undecylbenzenesulfonate and the difference in the flowing water volume between summer and winter, the fractions of domestic and agricultural wastewaters in the whole water column were calculated and the variety of the TOX sources in the river was estimated. The river carried about 100 kgCl of TOX materials in one day; about 50 kgCl of the materials was from residential area in the basin. The contribution of agricultural drainage from paddy field was not negligible in summer. Highly contribution of industrial wastewater was observed in a tributary Furuayase River basin while the amount of TOX loaded in the area was widely varied; 0–105 kgCl of the materials was discharged as industrial wastewater.