An Urban Atmospheric Diffusion Model for Traffic-Related Emission Based on Mass-Conservation and Advection-Diffusion Equations

This paper proposes an atmospheric diffusion model for traffic-related emission in urban areas within a few hundred meters from relevant roads. The model adopts the mass-conservation (MC) principle for the velocity calculation and the advection-diffusion (AD) equation for the concentration calculation. This MC+AD combination was chosen to achieve fast calculation for complex geometries. To compensate for the inherent deficiencies of MC and AD, as many known properties possible of turbulent boundary-layer flow over obstacles are incorporated into the MC calculation, and the diffusivity in AD is derived from the velocity spectrum as a function of distance from the emission source. The model is evaluated against wind-tunnel experiments ranging from point-source emission in uniform urban canopy to along-road emission in real city geometries. The model performs well in relatively simple configurations, but the performance deteriorates considerably as the complexity increases. However, in real city geometries, the model exhibits distinctly better performance in terms of statistical indices than a conventional Gaussian-plume model that neglects the effect of individual buildings. The model is therefore a viable option for environmental assessment.     

Estrogenic chemicals and estrogenic activity in leachate from municipal waste landfill determined by yeast two-hybrid assay

Estrogenic activity and estrogenic chemicals in landfill leachate were investigated by yeast two-hybrid assay and chemical analysis. Leachate sample extracted by liquid-liquid extraction with dichloromethane at pH 7.0 showed a higher dose-response curve than sample extracted at pH 3.0. or than sample extracted by solid phase extraction at either pH 7.0 or 3.0. The fraction extracted at pH 3.0 specifically inhibited not only growth of yeast but also estrogenic activity in this assay, suggesting that it contained anti-estrogenic chemicals. The greatest contributor to estrogenic activity among the chemicals identified in leachate extract was bisphenol A, with an estimated contribution ratio of 84%. The contribution ratios of 4-nonyl phenol (4-np) and 4-tert-octyl phenol (4-t-op) were estimated at 1.0%, and 0.1%, respectively, while natural estrogens such as 17beta-estradiol or estrone were below detection limit, so that their contribution ratio was estimated at no more than 10%. The estrogenic activity of leachate was decreased by aeration treatment alone after 7 days, and was no longer detected after 22 days. Concentrations of bisphenol A, 4-np and 4-t-op likewise decreased with aeration.     

Isotopic shifts with size, culture habitat, and enrichment between the diet and tissues of the Japanese scallop Mizuhopecten yessoensis (Jay, 1857)

Use of stable isotope signatures to trace diet patterns in cultured marine bivalves, particularly when changing culture habitat, requires knowledge of the isotopic shift and enrichment between diet and consumer’s tissues. The aim of this study was to determine the patterns of isotope change and the variability of enrichment values (∆δ¹³C and ∆δ¹⁵N) in different tissues (muscle, gonad, digestive gland) of the Japanese scallop (Mizuhopecten yessoensis). It was hypothesized that the isotopic signatures of a consumer’s tissues changed during settlement and that the changes were related to variations in the isotopic signatures of food sources and gut contents. Particular attention was paid to the isotope enrichment between the diet and a consumer’s tissues using isotope analysis of gut content. Muscle δ¹⁵N values decreased significantly 3–5 months post-settlement in a nearshore seabed, concomitant with the ingestion of lower δ¹⁵N food. For juvenile scallops, sinking particles (SP) were considered a more important dietary source than suspended particulate organic matter (SPOM), based on the correspondence between SP and gut contents δ¹³C. Enrichment values (∆δ¹³C and ∆δ¹⁵N) varied with tissue and season. ∆δ¹⁵N was 2.4‰ in muscle, 1.2‰ in gonad, and 0.7‰ in the digestive gland. ∆δ¹³C was 3.2‰ in muscle, 2.3‰ in gonad, and −0.5‰ in the digestive gland. ∆δ¹⁵N was the lowest in summer (0.3‰), and ∆δ¹³C was the highest in autumn (2.8‰). ∆δ¹⁵N values were significantly influenced by age, but not ∆δ¹³C. Patterns of isotope ratios and enrichment values may be related to physiological attributes and differences in diet. This is the first study to demonstrate isotopic shift and enrichment encountered in different tissues of a cultured scallop when changing culture habitat.     

Blue carbon in human-dominated estuarine and shallow coastal systems

Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO₂ to the atmosphere through air–sea CO₂ gas exchange, thus posing a dilemma on ESCS’s role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO₂ (C_atm), although the magnitude and determinants remain unclear. We argue that the phenomenon of net uptake of C_atm by ESCS is not unusual under a given set of terrestrial inputs and geophysical conditions. We assessed the key properties of systems that show the net C_atm uptake and found that they are often characteristic of human-dominated systems: (1) input of high terrestrial nutrients, (2) input of treated wastewater in which labile carbon is highly removed, and (3) presence of hypoxia. We propose that human-dominated ESCS are worthy of investigation as a contributor to climate change mitigation.     

A GIS-based evaluation of the effect of decontamination on effective doses due to long-term external exposures in Fukushima

Despite the enormous cost of radiation decontamination, there has been almost no quantitative discussion on how much it would reduce the long-term external radiation exposure in the Evacuation Zone and Planned Evacuation Zone (restricted zone) in Fukushima. The aim of this study is to assess the effectiveness of decontamination and return options and to identify important parameters for estimating the long-term cumulated effective dose (CED) during 15, 30 and 70 year period using data on land-use, population and decontamination in the restricted zone (about 1100 km²) in Fukushima.     

Urinary concentrations of organophosphorus insecticide metabolites in Japanese workers

A recent development in analytical chemistry has enabled us to monitor systemic organophosphorus insecticide (OP) exposure at individual levels. At present, however, limited data are currently available on urinary OP metabolite levels worldwide. The purpose of this study was to assess urinary dialkylphosphate (DAP) concentrations in Japanese workers. Urine samples were collected in both summer and winter from 339 Japanese adults who worked as food distributors (FDs, n = 164), apple farmers (AFs, n = 147) and pest control operators (PCOs, n = 28). DAPs were measured by gas chromatography-mass spectrometry after derivatization with pentafluorobenzylbromide. Dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP) and diethylthiophosphate (DETP) were detected in the urine of over 87% of the studied populations in both seasons. The geometric mean values of total DAPs (nmol g⁻¹ creatinine), DMP, DMTP, DEP and DETP (μg g⁻¹ creatinine) in summer and winter were 106.7 and 98.3, 7.0 and 3.8, 3.4 and 4.5, 0.8 and 1.5, and 0.3 and 0.2 for the FDs, 440.8 and 197.7, 33.1 and 10.8, 10.1 and 5.8, 4.2 and 4.7 and 1.6 and 0.8 for the AFs, and 473.4 and 284.6, 28.9 and 22.2, 17.6 and 4.6, 3.5 and 4.4, and 0.5 and 0.6 for the PCOs, respectively, thereby revealing significantly higher concentrations in AFs and PCOs groups than in the FDs in both seasons except for winter DMTP. These DAP concentrations were approximately the same or at lower levels compared with those reported in the previous literature. This is one of the first studies to demonstrate urinary DAP concentrations in Japanese adults.     

Characteristics of biosolids in dimethyl ether dewatering method

In this study, a method for removing water from biosolids that uses dimethyl ether (DME) as an extractant was considered. This study evaluates the applicability of the DME dewatering method to biosolid cakes by using a DME flow-type experimental apparatus. It was found that a high dewatering ratio is clearly achieved by increasing the liquefied DME/biosolid ratio and lowering the liquefied DME linear velocity. As the liquefied DME/biosolid ratio was increased, the carbon content in dewatered biosolid showed a slight decrease and the TOC concentration in separated liquid increased significantly. Finally, the input energy Es to remove 1 kg of water from the biosolid cake, using both the DME dewatering method and the conventional drying method was estimated. The calculation shows that Es for the DME dewatering process is approximately a third of Es for the conventional thermal drying process.     

气候变暖对黑龙江省水稻生产影响及对策研究

利用哈尔滨市和佳木斯市1951—2005年的气象资料,结合当地水稻生产的特点,研究了气候变暖对黑龙江省水稻的低温冷害、春季干旱、高温障碍和病虫草害等的影响。并在分析水稻生产中所存在的问题的基础上,提出了今后应对气候变暖、减轻灾害损失和实现水稻生产稳步发展的实用技术对策。同时分析了目前气候变暖研究中存在的问题,并提出了以消除城市热岛效应对气候观测指标的影响为核心,进一步深入研究气候变暖问题的新思路。     

Disrupting effects of hydroxy-polychlorinated biphenyl (PCB) congeners on neuronal development of cerebellar Purkinje cells: a possible causal factor for developmental brain disorders?

Polychlorinated biphenyls (PCBs) and hydroxy-PCB (OH-PCB) metabolites are widely distributed bioaccumulative environmental chemicals and have similar chemical structures to those of thyroid hormones (THs). Previously, we reported that THs are essential for neuronal development and the low doses of two OH-PCBs, namely, 4-OH-2',3,3',4',5'-pentachlorobiphenyl (4'-OH-PeCB-106) and 4-OH-2',3,3',4',5,5'-hexachlorobiphenyl (4'-OH-HxCB-159), inhibited the TH-dependent dendritic development of Purkinje cells in mouse cerebellar cultures using serum-free defined medium. To determine which type of OH-PCBs affect neuronal development, we further examined several OH-PCBs and other estrogenic chemicals using this simple and sensitive assay system. Two-way ANOVA was used to assess the effects of OH-PCBs and other chemicals on both factors of their concentrations and with/without T4 in the assay of TH-dependent dendritic development of Purkinje cells. Aside from the two OH-PCBs, 4-OH-2',3,4',5,6'-pentachlorobiphenyl (4'-OH-PeCB-121) and bisphenol A significantly inhibited the TH-dependent dendritic development of Purkinje cells, whereas 4-OH-2',3,3',5',6'-pentachlorobiphenyl (4'-OH-PeCB-112), 4-OH-2',3,3',5,5',6'-hexachlorobiphenyl (4'-OH-HxCB-165), 4-OH-2,2',3,4',5,5',6-heptachlorobiphenyl (4-OH-HpCB-187), progesterone and nonylphenol did not induce any inhibition, but significantly promoted the dendritic extension of Purkinje cells in the absence of THs. Other estrogenic chemicals, including beta-estradiol, diethyl stilbestrol and p-octylphenol did not show significant inhibitory or promoting effects. From these results, it is suggested that exposure to OH-PCBs and other environmental chemicals may disrupt normal neuronal development and cause some developmental brain disorders, such as LD, ADHD, and autism.