The pollution and ecological risk of endosulfan in soil of Huai’an city, China

Endosulfan, a persistent organic pollutant newly listed under the Stockholm Convention, is currently widely produced and used as a pesticide in China. Concentrations of endosulfans (including α-, β-isomers, and their metabolite endosulfan sulfate) were determined in surface soil collected from Huai’an city, where the largest endosulfan producer is located. The concentrations of Σendosulfan (sum of α-endosulfan, β-endosulfan, and endosulfan sulfate) at all sites ranged from 0.28 to 44.81?ng/g dry weight (dw), following a lognormal distribution. The geometric mean was 1.09?ng/g dw, and the geometric standard deviation was 3.02. The β-endosulfan levels were consistently greater than those of α-isomer. The concentration ratios of α-endosulfan to β-endosulfan ranged from 0.03 to 0.70, which were much lower than the commercial endosulfan mixture. This is because that α-endosulfan is more volatile and degrades faster than β-endosulfan in soil. The contour map of Σendosulfan levels in soil indicates that the factory was the point pollution source with the highest endosulfan level in its surrounding area, especially the southern area. However, the non-point agricultural sources are more important. Based on Monte Carlo simulation, the Σendosulfan inventory in soil in Huai’an is estimated to be 0.8–3.0 tons. In order to understand the potential ecological risk of endosulfan, the Monte Carlo-based hazard quotient distribution was estimated and showed that Σendosulfan posed a potentially high risk to soil organisms. To our knowledge, this study is the first that reports soil pollution and risk of endosulfan around the manufacturer in China. This study will help China’s implementation of Stockholm Convention for the reduction and elimination of endosulfan in future.     

Development of a dynamic transfer model of (14)C from the atmosphere to rice plants

A dynamic compartment model was investigated to describe ¹⁴C accumulation in rice plants exposed to atmospheric ¹⁴C with temporally changing concentrations. In the model, rice plants were regarded to consist of three compartments: the ear and the mobile and immobile carbon pools of the shoot. Photosynthetically fixed carbon moves into the ear and the mobile carbon pool, and these two compartments release a part of this carbon into the atmosphere by respiration. Carbon accumulated in the mobile carbon pool is redistributed to the ear, while carbon transferred into the immobile carbon pool from the mobile one is accumulated there until harvest. The model was examined by cultivation experiments using the stable isotope, ¹³C, in which the ratios of carbon photosynthetically fixed at nine times during plant growth to the total carbon at the time of harvest were determined. The model estimates of the ratios were in relatively good agreement with the experimental observations, which implies that the newly developed compartment model is applicable to estimate properly the radiation dose to the neighboring population due to an accidental release of ¹⁴C from nuclear facilities.     

Timing of metamorphosis and larval segregation of the Atlantic eels Anguilla rostrata and A. anguilla, as revealed by otolith microstructure and microchemistry

Otolith microstructure and microchemistry were examined in juveniles of American (Anguilla rostrata) and European (A. anguilla) eels. Otolith increment width markedly increased from age 132 to 191 d (156 ± 18.9 d; mean ± SD) in A. rostrata and 163 to 235 d (198 ± 27.4 d; mean ± SD) in A. anguilla, both of which were coincident with drastic decreases in otolith Sr:Ca ratios, suggesting that metamorphosis from leptocephalus to glass eel began at those ages in each species. The duration of metamorphosis was estimated to be 18 to 52 d from otolith microstructure, for both species studied. Ages at recruitment were 171 to 252 d (206 ± 22.3 d; mean ± SD) in A. rostrata and 220 to 281 d (249 ± 22.6 d; mean ± SD) in A. anguilla. In these two species, positive linear relationships were found in ages between the beginning of metamorphosis and recruitment, suggesting that early metamorphosing larvae recruited at younger ages. Duration of the leptocephalus stage to recruitment in A. anguilla was about 40 d longer than that in A. rostrata. The geographical segregation between the two species in the Atlantic Ocean seems to be involved in the differences in the duration of the leptocephalus stage (age at metamorphosis). Received: 8 November 1999 / Accepted: 8 May 2000     

Sanitation of seawater effluent from seaweed processing plants using a photo-catalytic TiO2 oxidation

A fine porcelain open-cell photo-catalytic filter with titanium dioxide (TiO(2)) was evaluated for sterilization and sanitation of bio-polluted industrial water. In simulated seawater industrial effluent samples, the populations of Escherichia coli and Vibrio parahaemolyticus quickly decreased and reached non-detectable level within 10min. In seawater effluents from a seaweed processing plant, the bacterial populations in two samples quickly decreased by more than 10(3). In another two samples the decreases were slow and lowered by less than 10(2). Using fluorescence microscopy, it was indicated that the bacterial cells treated with photo-catalytic TiO(2) were damaged. In addition, the protein concentration in simulated seawater effluent slowly decreased using the photo-catalytic TiO(2) reaction; and reached similar concentrations as seawater near cultured seaweed beds. These results indicate that using a reactor with a TiO(2) photo-catalyst filter was effective for the sanitation of seawater effluents.     

Steam gasification of epoxy circuit board in the presence of carbonates

To recover useful metals from end-of-life electronic devices and to convert plastic components from these devices into clean fuel gas, steam gasification of epoxy board samples was carried out at 600–700?°C and 0.1?MPa pressure in the presence of a ternary eutectic carbonate (lithium carbonate, sodium carbonate, and potassium carbonate). Hydrogen and carbon dioxide were the main products, and methane and carbon monoxide were detected as minor products. The gasification proceeded in two steps: an initial rapid pyrolysis followed by secondary steam gasification of char produced from the pyrolysis. The ternary eutectic carbonate accelerated not only the latter steam gasification but also the initial rapid pyrolysis. The activation energy for the steam gasification of epoxy board samples in the presence of the carbonate was 122?kJ/mol.     

Differential assimilation of nitrogen dioxide by 70 taxa of roadside trees at an urban pollution level

In order to screen for the best species for mitigating nitrogen dioxide (NO2) by plants at urban levels, we investigated assimilation of nitrogen dioxide by 70 taxa of woody plants that are mostly utilized as roadside trees. They were fumigated with 15N-labeled NO2 at 0.1 microl l(-1) for 8h, and the amount of reduced nitrogen derived from NO2 (in mg Ng(-1) dry weight) in the leaves (designated NO2 assimilation capability hereafter) were determined. Data were analyzed in the comparison with the previously reported ones obtained at 4 microl l(-1) NO2. Among the 70 taxa, the value of NO2 assimilation capability differed by a factor of 122 between the highest (Prunus yedoensis; 0.061) and the lowest (Cryptomeria japonica; 0.0005). Based on the analysis of NO2 assimilation capability values at 0.1 and 4 micro l(-1) NO2, the 70 taxa of woody plants appeared to be classified into four types; those of high NO2 assimilation and high NO2 resistance, those of high NO2 assimilation but low NO2 resistance, those of low NO2 assimilation and low NO2 resistance, and those of low NO2 assimilation but high NO2 resistance. The first, second, third and fourth types include 13, 11, 35 and 11 taxa, respectively. The broad-leaf deciduous trees may have advantages of high biomass and fast growth as compared with woody plants of other habits. Thus, four broad-leaf deciduous species, Robinia pseudo-acacia, Sophora japonica, Populus nigra and Prunus lannesiana, were concluded here to be the best phytoremediators for the urban air.     

Light Stability of Oriental Lacquer Films Irradiated by a Fluorescent Lamp

Oriental lacquer film was prepared and exposed to a fluorescent lamp. The color difference and gloss of the surface of the film decreased compared to those of film kept in a dark place by irradiation with the fluorescent light. The percentage of discoloration was 7.0% on a relative scale with an irradiation of 3600 h. The surface of the film was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The oxygen content of the surface increased considerably with the decrease in triene groups with exposure time. These changes were also observed when the film was exposed in a glass or acrylic plate box. The change of the above properties was not observed when the film was kept in a dark place for more than 4800 h. The results suggest that oriental lacquer film deteriorates even under irradiation with visible light.     

Distribution and abundance of finless porpoise in the Inland Sea of Japan

Aerial sighting surveys were conducted in 2000 to evaluate the distribution and abundance of finless porpoise Neophocaena phocaenoides in the Inland Sea of Japan. We flew 60 north–south transects (2,218 km in total) at intervals of 6.43 km over the study area between 131°3′ and 134°59′ E. In total, 148 groups were detected by two observers. The average group size was 1.56 individuals. The effective strip half-width of each observer was estimated to be 107 m (coefficient of variation [CV] = 8.26%). Porpoise abundance was estimated at 7,572 individuals and the density was as low as 0.506 individuals/km² (CV = 17.3%). The sea is among the Japanese waters with the lowest density in spite of its favorable topographical conditions. In the western stratum of the study area, where the estimated density was 1.31 individuals/km², we observed a relatively regular distribution. In the central-eastern stratum, which had an estimated density of 0.208 individuals/km², we confirmed a clumped distribution that was restricted to inshore waters or near islands. No individuals were observed in waters between 132°51′ and 133°11′E, and between 133°43′ and 133°59′E, where sand dredging and other human activities have been active, suggesting that habitat fragmentation has occurred.     

Influence of cetane improvers on the air quality in an urban street canyon

The concentration distributions of NO_x, PM, HC and CO in an urban street canyon have been estimated using a two-dimensional air quality numerical model based on the k– turbulent model and the atmospheric convection diffusion equation when various cetane improvers were used in diesel fuels. A wind vortex can be found within the street canyon, and the pollutants emitted from the bottom of the street canyon tend to follow the course of the wind field, moving circularly. The addition of cetane improvers can improve the air quality in a street canyon, all of the pollutants were found to decrease with increasing centane number.     

Atmospheric Budget of Non-Seasalt Chlorine in the Kanto District,Japan

To evaluate the influence of anthropogenic emission of HCl on the air quality in the Kanto district of Japan, the atmospheric budgetof non-seasalt Cl (nssCl) was analyzed. The Kanto district, which consists of the Tokyo metropolis and the six surrounding prefectures, is the most densely populated region in Japan. The emission intensity of HCl is extremely high compared with those in other regions and most western countries. In this study, the annual wet and dry depositions of nssClwere estimated on a 0.25 × 0.25° grid over the Kanto district based on the concentration monitoring resultsand meteorological data. The budget analysis was conducted by comparing the estimated deposition with the emission of HCl. As a result, the annual total (wet + dry) deposition of nssCl was estimated to be 32 kt yr^-1, which closely agreed with HCl emission (36 kt yr^-1) from waste incineration in this area. The result suggested that the anthropogenic emission of HCl had a significant influence on the air quality and the deposition of acidity in this area.