Environmental monitoring of historical change in arsenic deposition with tree bark pockets

ICP-MS analysis recorded historical change (c. 1846 to 2002) in the arsenic concentration of bark included within the trunks (tree bark pockets) of two Japanese oak trees (Quercus crispula), collected at an elevated location approximately 10 km from the Ashio copper mine and smelter, Japan. The arsenic concentration of the bark pockets was 0.016 +/- 0.003 microg cm(-2) c. 1846 (n = 5) and rose 50-fold from c. 1875 to c. 1925, from approximately 0.01 to 0.5 microg cm(-2). The rise coincided with increased copper production in Ashio from local sulfide ores, from 46 tons per year in 1877 to 16,500 tons per year in 1929. Following a decline in arsenic concentration and copper production, in particular during the Second World War, a second peak was observed c. 1970, corresponding to high levels of production from both local (6,000 tons per year) and imported (30,000 tons per year) ores, smelted from 1954. Compared to the local ores, the contribution of arsenic from imported ores appeared relatively low. Arsenic concentrations declined from c. 1970 to the present following the closure of the mine in 1974 and smelter in 1989, recording 0.058 +/- 0.040 microg cm(-2) arsenic (n = 5) in surface bark collected in 2002. The coincident trends in arsenic concentration and copper production indicated that the bark pockets provided an effective record of historical change in atmospheric arsenic deposition.     

Accumulation of endocrine disrupting chemicals (EDCs) in the polychaete Paraprionospio sp. from the Yodo River mouth,Osaka Bay,Japan

This study presents the levels of endocrine disrupting chemicals (EDCs) accumulated by Paraprionospio sp. from the Yodo River mouth, Osaka Bay. Since high concentrations of nonylphenol (NP), bisphenol A (BP), octylphenol (OP), 17β-estradiol (E2), and estrone (E1) have been measured in sediment from Osaka Bay, some bioaccumulation could be expected particularly in benthic animals. EDCs were analysed in Paraprionospio sp., a dominant benthic species in Osaka Bay. The results showed that Paraprionospio sp. had accumulated varying concentrations (wet weight; w.w.) of NP at 1,460–4,410 ng/g; BP at 22.5–39.6 ng/g; OP at 18.9–45.4 ng/g; E2 at 0.89–4.35 ng/g; and E1 at 0.06–2.50 ng/g. Accumulation of NP and OP were highest among the samples gathered in summer (July 2008), while concentrations of BP, E2, and E1 did not much differs within 3 years. EDC levels in Paraprionospio sp. were apparently greater than those in sediments showing bioaccumulation.     

Analysis of running child pedestrians impacted by a vehicle using rigid-body models and optimization techniques

Lack of information from vehicle-to-child pedestrian impacts provides considerable challenges when developing vehicle countermeasures for the pediatric population. Crash reconstructions of real-world incidents provide useful information about the vehicle damage and injury outcome but do not permit definitive and quantitative measures of the impact severity given the high level of uncertainty in the initial conditions of the pedestrian and the vehicle prior the impact. This paper develops an advanced methodology for reconstructing child pedestrian–vehicle impacts that combines the crash data with multi-body simulations and optimization techniques for identifying the pedestrian posture and vehicle speed prior to impact. For the child pedestrian posture, a continuous sequence of the running gait was developed based on the literature data and simulations. Using vehicle damage information from an actual child pedestrian crash, an objective function was developed that minimized the difference between vehicle and pedestrian contact points for the simulated child postures, pedestrian, and vehicle speeds. Simulated annealing and genetic optimization algorithms were used to identify sets of potential solutions for the pedestrian and vehicle initial conditions. Local minimums were observed for several response surfaces of the objective function which shows the non-convex nature of the crash reconstruction optimization problem with the chosen objective function. Based on the results of the real-world reconstruction, this study indicates that numerical simulations coupled with heuristic optimization algorithms can be used to reconstruct child pedestrian and vehicle pre-impact conditions.     

Comparison of marginal abatement cost curves for 2020 and 2030: longer perspectives for effective global GHG emission reductions

This study focuses on analyses of greenhouse gas (GHG) emission reductions, from the perspective of interrelationships among time points and countries, in order to seek effective reductions. We assessed GHG emission reduction potentials and costs in 2020 and 2030 by country and sector, using a GHG emission reduction-assessment model of high resolution regarding region and technology, and of high consistency with intertemporal, interregional, and intersectoral relationships. Global GHG emission reduction potentials relative to baseline emissions in 2020 are 8.4, 14.7, and 18.9 GtCO₂eq. at costs below 20, 50, and 100 $/tCO₂eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and 26.6 GtCO₂eq. at costs below 20, 50, and 100 $/tCO₂eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and 26.6 GtCO₂eq. at costs below 20, 50, and 100 /tCO₂eq., corresponding to +33, +8, and −3 %, respectively, relative to 2005. Global emission reduction potentials at a cost below 50 $/tCO₂eq. for nuclear power and carbon capture and storage are 2.3 and 2.2 GtCO₂eq., respectively, relative to baseline emissions in 2030. Longer-term perspectives on GHG emission reductions toward 2030 will yield more cost-effective reduction scenarios for 2020 as well.     

Spectroscopic analysis of NIR-dye sensitization in bulk heterojunction polymer solar cells

The photovoltaic conversion efficiency for near-infrared (NIR) sunlight is improved successfully by dye sensitization of bulk heterojunction polymer solar cells, in which the active layer was prepared by a ternary blend of poly(3-hexylthiophene), a fullerene derivative (1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene), and an NIR dye, silicon phthalocyanine bis(trihexylsilyl oxide). The mechanism of the NIR-dye sensitization is studied by femtosecond transient absorption spectroscopy.     

Consistent assessments of pathways toward sustainable development and climate stabilization

Many of the numerous difficult issues facing the world today involve relationships entailing trade‐offs and synergies. This study quantitatively assesses some alternative scenarios using integrated assessment models, and provides several indicators relating to sustainable development and climate change, such as indicators of income (per capita GDP), poverty, water stress, food access, sustainable energy use, energy security, and ocean acidification, with high consistencies among the indicators within a scenario. According to the analyses, economic growth helps improve many of the indicators for sustainable development. On the other hand, climate change will induce some severe impacts such as ocean acidification under a non‐climate intervention scenario (baseline scenario). Deep emission reductions, such as to 2°C above the pre‐industrial level, could cause some sustainable development indicators to worsen. There are complex trade‐offs between climate change mitigation levels and several sustainable development indicators. A delicately balanced approach to economic growth will be necessary for sustainable development and responses to climate change.     

A research on dioxin generation from the industrial waste incineration

By using fluidized-bed furnace and rotary-kiln+stoker furnace and four different kinds of industrial wastes such as waste wood, coffee mill, waste oils and waste plastics, we have drawn the following conclusions:

(1) A relationship between H6CBz and DXN is acquired, which is DXN=0.34×H6CBz^1.1.

(2) The following means of emission reduction can be considered. (a) Reduction of DXN and Cl accumulation within the furnace, (b) control by the incinerated object, (c) control through the precursors of H6CBz, (d) improvement through operational control, (e) ammonia injection into the high-temperature zone of the furnace seems to be effective in reducing DXN and (f) DXN concentration is high with CO above 1800 ppm, though it decreases with CO below ≈10 ppm.     

Mass balance of arsenic and antimony in municipal waste incinerators

The arsenic and antimony balance in two municipal waste incinerators was investigated. Initially, the production rates of ash and wet scrubber effluent were estimated. Then the arsenic and antimony in the ash and wet scrubber effluent were determined, which gave an estimate of the elemental balance. The total amounts of arsenic and antimony in the municipal waste were 0.9 g/t and 30–44 g/t, respectively. The distributions to fly ash were 45–47% and 33–74% for arsenic and antimony, respectively. The distribution mechanisms of arsenic and antimony are discussed from the viewpoints of their thermodynamics as well as their initial valencies, which greatly affect their behaviour. Received: July 2, 1998 / Accepted: February 27, 1999