Removal of thiobencarb in aqueous solution by zero valent iron

A cost-effective method with zero valent iron (ZVI) powder was developed for the purification of thiobencarb (TB)-contaminated water. The removal treatment was performed in the batch system. A sample solution of 10 ml containing 10 microg ml(-1) of TB could be almost completely treated by 100mg of ZVI at 25 degrees C for 12h of treatment time. Since the formation of chloride ion in the aqueous solution during the treatment of TB was observed, the removal of TB with ZVI may contain two processes: reduction (degradation) and adsorption. Because the present treatment for TB is simple, easy handling and cheap, the developed technology with ZVI can contribute to the treatment of agricultural wastewaters.     

Wastewater treatment with multilayer media of waste and natural indigenous materials

Wastewater treatment using waste materials (refuse concrete, waste paper and charcoal) and natural indigenous rocks (andesite, limestone, granite and nitrolite) in the form of multilayer media was investigated. The removal of suspended solids (SS), phosphate ion, nitrate ion, ammonium ion, toxic metals and chemical oxygen demand (COD) were evaluated for the multilayer wastewater treatment system. Effective removal of heavy metals such as cadmium, chromium, mercury and lead was demonstrated. SS and phosphate ion were removed with relatively high efficiency and the COD after treatment was lessened using certain combinations of media. The present wastewater treatment system is simple, convenient and low cost. Therefore, this method can be applied in small scale plants for wastewater treatment in local and nonexclusive areas.     

Host preference of a symbiotic flatworm in relation to the ecology of littoral snails

Some polyclads associate with other marine invertebrates such as gastropods, but how these associations evolve is not well understood. This study examined the relationships between a polyclad, Stylochoplana pusilla, and six species of snails in 10 eulittoral sites in Mutsu Bay, northern Japan, in 2010 and 2011. Of the six potential host snail species, Monodonta labio was present at all sites and the prevalence of S. pusilla in the snails’ mantle cavities overall was 82.6 %. Four other snail species occurred at five or six sites in comparable densities, but of these, only Chlorostoma turbinatum and Omphalius rusticus had S. pusilla in their mantle cavities (prevalence of 42.0 and 15.4 %). A congener of M. labio, Monodonta neritoides, occurred at only one site and had no S. pusilla. The mantle, which provides habitat space for S. pusilla, was proportionally the longest in M. labio. In laboratory experiments, the flatworms preferentially entered M. labio over other snail species with the same mantle length. Observed vertical distributions of snails in the littoral zone indicate that M. labio is present in the eulittoral at both high and low tides, while C. turbinatum and O. rusticus are usually found in the sublittoral. In an evolutionary sense, the relationship between S. pusilla and its host may have developed as a mechanism for the flatworm to avoid predation by living in the eulittoral and to avoid desiccation by establishing commensal relationships with certain snails.     

Partitioning of polar and non-polar neutral organic chemicals into human and cow milk

The aim of this work was to develop a predictive model for milk/water partition coefficients of neutral organic compounds. Batch experiments were performed for 119 diverse organic chemicals in human milk and raw and processed cow milk at 37°C. No differences (<0.3 log units) in the partition coefficients of these types of milk were observed. The polyparameter linear free energy relationship model fit the calibration data well (SD=0.22 log units). An experimental validation data set including hormones and hormone active compounds was predicted satisfactorily by the model. An alternative modelling approach based on log K(ow) revealed a poorer performance. The model presented here provides a significant improvement in predicting enrichment of potentially hazardous chemicals in milk. In combination with physiologically based pharmacokinetic modelling this improvement in the estimation of milk/water partitioning coefficients may allow a better risk assessment for a wide range of neutral organic chemicals.     

Impacts of converting from leaded to unleaded gasoline on ambient lead concentrations in Jakarta metropolitan area

Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, iron （Fe）, lead （Pb）, potassium （K）, zinc （Zn）, titanium （Ti）, manganese （Mn）, bromine （Br）, copper （Cu）, chromium （Cr）, nickel （Ni）, and vanadium （V） were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles.     

Soil erosion and its impacts on water treatment in the northeastern provinces of Thailand

The economy of Northeast Thailand is mainly based on agriculture. The transformation of forestlands to agricultural areas and the encroachment of riverbanks within the Phong watershed have caused severe soil erosion. Strong storms in rainy season exacerbate the problem of soil erosion. Difficulty in getting water drives people in the upstream region to live on riverbanks. Soil erosion affects water utility by increasing the turbidity in the Phong River and also by decreasing the water storage capacity of small reservoirs for the upstream residents, as well as that of the Ubolratana Dam. The rate of siltation in the Ubolratana Dam was estimated to be 1.5 million tons/year during 1965-1990. The main source of water supply is surface water in the Phong watershed, and fluctuating turbidity makes water treatment difficult. The maximum turbidity in the upstream Phong River exceeds 5000 NTU, whereas it is reduced to be about 300 NTU at the intake point of Khon Kaen Municipal Water Treatment Plant because the Ubolratana Dam works as a huge clarifier. Khon Kaen Municipal Waterworks has a daily water supply of 72,960 m3/day. The average amounts of alum used in the wet (May-October) and dry (November-April) periods are 42.33 g/m3 and 28.46 g/m3, respectively. The average costs of the amounts of alum used are 0.213 and 0.143 Bahts/m3 during the wet and dry periods, respectively. Fluctuation of turbidity in raw water makes it difficult to adjust alum dose, resulting in treated water quality unstable, and handling of sludge disposal difficult.     

Effect of manufacturing methods of AgCl/Al2O3 catalyst on selective catalytic reduction of NOx

The AgCl/Al2O3 catalyst has potential for use in the selective catalytic reduction (SCR) of NOx. A compound hydrocarbon, following oxygenation is used as a type of reducing agent. In this experiment, the AgCl/Al2O3 catalyst was produced by four different methods, and the differences among their reduction catalysis of NOx were compared. Ethanol was used as a type of reducing agent. X-ray diffraction analysis was performed to study the crystalline structure and scanning electron microscope and transmission electron microscope (TEM) were applied to determine the microindentation. The results indicated that, in the range of 350–400°C, there was no significant difference on the NOx reduction rate; however, there was dispersion at high and low temperature ranges. The size of the AgCl particles was about 20–100 nm.     

Sources and distribution of hexabromocyclododecanes (HBCDs) in Japanese river sediment

The distribution of hexabromocyclododecane (HBCD) in the sediment of three Japanese rivers with different characteristics (i.e., population and potential source in the catchment) was investigated and compared with the results estimated using a multimedia fate model (ChemCAN). High concentrations of HBCD in sediments in the range of 134-2060 ng g(-1) were found in a river receiving textile wastewater. This contrasted with the much lower concentrations (0.8-4.8 ng g(-1)) observed for an urban river (with a surrounding population of 1.8 million). The medians of observed HBCD concentrations in each river were close to those estimated based on the assumed input source (e.g., 1810 ng g(-1) for the observed median concentration, and 1436 ng g(-1) for the estimation, in the Kuzuryu River). These results demonstrated the importance of considering source contributions of HBCD, including both industrial and consumer sources, to aquatic environments, for reliable risk management.     

Perceived predation risk and mate defense jointly alter the outcome of territorial fights

Virtually all animal conflicts occur over access to mates or resources that affect survival, the two key components of fitness. In this paper, we report that predation risk and mate defense jointly affect the outcomes of contests between male sand crabs (Scopimera globosa) for burrows in which crabs mate and take shelter from predators. We observed the contests under three different conditions: (1) the natural condition of low predation risk and without the presence of a female; (2) the first experiment in which we imposed upon only intruding males the perception of predation risk—by digging them from their burrows, capturing and handling them, and placing them into other males’ burrows—to increase the value of the burrows for the intruders as shelter, and (3) the second experiment in which we repeated this treatment but increased the resource value of the burrow to the resident by placing a female in his burrow. The difference in body size between contestants was the main determinant of victory in all analyses. However, perceived predation risk also partly affected the outcomes of the fights: The motivated intruders were likely to win even when they were a little smaller than the residents. In addition, defense of a female had a significant effect on the outcomes of fights: The motivated residents won more fights than the motivated intruders, indicating that these two treatments caused asymmetric increases of the resource value. This is the first report of two external factors simultaneously raising resource value, affecting motivation of contestants, and altering the outcome of fights.     

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.