Influence of various reaction parameters on 2,4-D removal in photo/ferrioxalate/H(2)O(2) process

The influence of various reaction parameters on herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) removal were examined in the photo/ferrioxalate/H(2)O(2) system, with regard to: (1) sulfate, phosphate, and z.rad;OH scavenger, as solution constituent; and (2) light intensity, ferrioxalate, H(2)O(2), and oxalate concentration, as operating parameter. In terms of 2,4-D removal, the photo/ferrioxalate/H(2)O(2) system has always been superior to the photo/Ferric ion/H(2)O(2) system, despite the high presence of anions (sulfate 100 mM, phosphate 1 mM) or z.rad;OH scavenger. Not only the rate of 2,4-D removal, but also the decomposition rate of H(2)O(2) and oxalate proportionally increase with light intensity. The ferrioxalate concentration determines the light absorption fraction, and thus, controls the rates of 2,4-D removal, and the decomposition of H(2)O(2) and oxalate, are predicted from kinetic formulations. The optimal concentration of H(2)O(2) and oxalate, according to the extent of the z.rad;OH scavenging reaction with these reagents, has been demonstrated for 2,4-D removal. It was found that an increasing oxalate concentration, which bears the burden of increased dissolved organic carbon (DOC), does not occur. This is because its decomposition, as a result of the photochemical reduction of the ferric oxalate complex, results in a decrease of the equivalent DOC. The importance of the key reaction factors to be considered, when applying this system to real wastewater treatment, is also discussed.     

Trichloroethylene degradation by photocatalysis in annular flow and annulus fluidized bed photoreactors

The effects of trichloroethylene (TCE) gas flow rate, relative humidity, TiO(2) film thickness, and UV light intensity on photodegradation of TCE have been determined in an annular flow type photoreactor. Phosgene and dichloroacetyl chloride formation could be controlled as a function of TCE gas flow rate and photodegradation of TCE decreased with increasing relative humidity. The optimum thickness of TiO(2) film was found to be approximately 5 mum and the photocatalytic reaction rate of TCE increased with square root of UV light intensity. In addition, the effects of the initial TCE concentration, phase holdup ratio of gas and solid phases (epsilon(g)/epsilon(s)), CuO loading on the photodegradation of TCE have been determined in an annulus fluidized bed photoreactor. The TCE photodegradation decreased with increasing the initial TCE concentration. The optimum conditions of the phase holdup ratio (epsilon(g)/epsilon(s)) and CuO wt.% for the maximum photodegradation of TCE was found to be 2.1 and 1.1 wt.%, respectively. Therefore, an annulus fluidized bed photoreactor is an effective tool for TCE degradation over TiO(2)/silica gel with efficient utilization of photon energy.     

Mercury and cadmium in common cormorants (Phalacrocorax carbo)

Mercury (Hg) and cadmium (Cd) in common cormorants (Phalacrocorax carbo) collected in Lake Biwa, Japan and Tokyo, Japan, were investigated to elucidate the biological behaviors of these elements, and to assess exposure to these pollutants of wild, fish-eating birds. Hg and Cd concentrations were highest in the liver and kidneys, respectively. The lowest levels of both elements were observed in chicks. Hg concentrations in all tissues except brain increased significantly with growth from chicks to juveniles (p<0.05, U-test). Cd concentrations in the kidneys and liver also increased significantly during growth from juvenile to adult (p<0.005, U-test). When comparing hepatic Hg and Cd in adult birds between 10 samples from Lake Biwa and nine samples from Tokyo, the Cd concentrations in the Lake Biwa samples (1.4+/-0.37 microg/g dry wt) (mean+/-SD) were significantly higher than those from Tokyo (0.32+/-0.16 microg/g dry wt) (p<0.005, U-test), while no statistically significant difference was found in the Hg concentrations. Possible causes of these differences were discussed in relation to their prey.     

Factors influencing natural occurrence of fluoride-rich groundwaters: a case study in the southeastern part of the Korean Peninsula

Factors regulating the occurrence of fluoride in groundwater were investigated using natural isotope tracers and geochemical data in the southeastern part of Korea where about 10% of the total public water-supply wells (n=422) inspected in this study had fluoride levels exceeding the drinking water limit of Korea (1.5 mg/l). The F-rich public wells are mostly distributed along the major faults, especially in the terrain of the F-rich granitic rocks. The stable isotope analysis results provide substantial information for the relative ages of groundwaters. It is revealed that the F-rich groundwaters are deeply circulating paleogroundwaters and occur along the faults due to upward flow along the fault plane. While reacting with granitic rocks for a prolonged period, the F concentrations of groundwater are continuously enriched even after the groundwater reaches an equilibrium state with respect to fluorite (CaF2) due to removal of Ca by precipitation of calcite (CaCO3). These observations reflect that rock chemistry, groundwater age, well depth, and geologic structure are the important factors controlling the occurrence of high F groundwaters. However, high F groundwaters are rarely observed in the fault zones where the associated fractures are widely developed. Isotopic signature provides an evidence for deep penetration of recently recharged groundwater into the wide fault zone, indicating that the hydrologic condition of the fault is also an important factor controlling the occurrence of high F groundwaters.     

The bacterium<Emphasis Type="Italic"> Xenorhabdus nematophila</Emphasis> inhibits phospholipases A<Subscript>2</Subscript> from insect,prokaryote, and vertebrate sources

The bacterium, Xenorhabdus nematophila, is a virulent insect pathogen. Part of its pathogenicity is due to impairing cellular immunity by blocking biosynthesis of eicosanoids, the major recognized signal transduction system in insect cellular immunity. X. nematophila inhibits the first step in eicosanoid biosynthesis, phospholipase A₂ (PLA₂). Here we report that the bacterium inhibits PLA₂ from two insect immune tissues, hemocytes and fat body, as well as PLA₂s selected to represent a wide range of organisms, including prokaryotes, insects, reptiles, and mammals. Our finding on a bacterial inhibitor of PLA₂ activity contributes new insight into the chemical ecology of microbe–host interactions, which usually involve actions rather than inhibitors of PLA₂s.     

Methane Emissions from Landfills and Carbon Dynamics of Harvested Wood Products: The First-Order Decay Revisited

The First-Order decay method for carbon stocks is derived from first principles, and applications in the context of national greenhouse gas inventories are discussed. For methane emissions from landfills a method is developed that in principle is more accurate than the method currently recommended by the IPCC, and systematic errors are estimated numerically. The First-Order decay method is further applied to derive the permanent part of the carbon pool of harvested wood products.     

Simultaneous Measurements of Atmospheric Pollutants and Visibility with a Long-Path DOAS System in Urban Areas

In this paper, the applicability of a Long-Path Differential Optical Absorption Spectroscopy (LP-DOAS) system was checked for the feasibility of the simultaneous measurement of trace gases (such as O₃, NO₂, SO₂, and HCHO) and atmospheric visibility (light extinction by aerosols) in Asian urban areas. Field studies show that an LP-DOAS system can simultaneously measure the key pollutants (such as O₃, NO₂, SO₂, and HCHO) at detection limits in the ppb/sub-ppb range as well as the Mie extinction coefficient with an uncertainty of 0.1 km^–1 at time resolution of a few minutes. It is thus concluded that the use of LP-DOAS system is feasible for simultaneous measurement of gaseous pollutants as well as an atmospheric extinction coefficient which is tightly bound to fine particulate concentration.     

Biological Roles of Trace Metals in Natural Waters

For decades there has been an intense interest in the toxic effects of trace metals on biological organisms in the environment. This period of time has seen increasing improvements in analytical techniques for the measurement and study of trace metals and their subsequent application to a broad spectrum of water systems around the globe. This work has included studies of the geographical distributions of trace metals in different water types in the ocean, the modes of transport and uptake of trace metals and the study of historical changes in trace metal accumulation. Early research highlighted strong similarities in the behaviours of many trace metals and those of well-understood chemical nutrients such as phosphate, nitrate and silicate, known to be essential for phytoplankton growth in the ocean. This suggests that phytoplankton regulate the trace metal composition of seawater for their own benefit. A major achievement in this regard has been the ability to measure, at the sub-nmol/L level, trace metal species that are complexed by naturally-occurring organic ligands of biological origin in ocean waters. It is now clear that the free ion activities of many essential and/or toxic trace metals are regulated by highly specific, strongly complexing ligands exuded by marine phytoplankton. This research encourages a new paradigm in which the growth rates and species composition of primary marine organisms are affected by trace metals at concentration levels orders of magnitude lower than is conventionally believed. As a consequence, the capacity of natural waters to assimilate trace metal-contaminants may be correspondingly much lower than is currently thought reasonable.     

Heavy metal uptake in transplanted and in situ yarrow (Achillea millefolium) and epiphytic cryptogams at rural,urban and industrial localities in Denmark

Yarrow (Achillea millefolium L.) and 3 cryptogamic epiphytes were collected from and transplanted to 10 various locations in Denmark. The spatial and temporal variation in Pb and Cd concentrations of yarrow leaves and the cryptogams were determined. The physical structure of the plant parts, the mobility differences between the metals and the atmospheric fallout of metals at the growing site were believed to be important for the metal uptake. It was concluded, that yarrow leaves give a measure of the relative variation in deposition rates to surface of higher plants when collected at the end of a growth season, and that the geographic variation was revealed with similar accuracy by yarrow and the cryptogams.     

Comparison of epidemiology and injury profile between vulnerable road users and motor vehicle occupants in road traffic fatalities

Objective: Road traffic injuries (RTIs) are a major global health issue causing a global burden of mortality and morbidity. Half of all fatalities on the world’s roads are vulnerable road users (VRUs). The targeted intervention strategies based on fatality analysis focusing on VRUs can effectively contribute to reducing RTIs. This study aimed to compare VRUs and motor vehicle occupants (MVOs) in terms of epidemiology and injury profile.

Methods: We utilized a nationwide, prospective database of RTI-related mortality cases for patients who visited 23 emergency departments between January 2011 and December 2015. All fatalities due to RTIs in the prehospital phase or in-hospital were eligible, excluding patients with unknown mode of transport and those admitted to general wards. The primary and secondary outcomes were fracture injuries and visceral injuries diagnosed using the International Classification of Diseases, Tenth Revision (ICD-10). We compared fracture injuries between VRUs and MVOs using Abbreviated Injury Scale (AIS) 2? and 2+ classification.

Results: Among a total 3,694 road traffic fatalities (RTFs), 43.3% were pedestrians, followed by MVOs (27.0%), motorcyclists (18.9), bicyclists (6.6%), and agricultural vehicle users (4.2%). The elderly (>60 years old) accounted for 54.9% of VRU fatalities. RTFs occurred most frequently in the autumn and the VRU group and the MVO group showed significant differences in weekly and diurnal variation in RTFs. The injury severities (AIS 2+) of the head, neck, and thorax were significantly different between the 2 groups (P?Conclusions: Elderly pedestrians should be targeted for decreases in RTFs, and road traffic safety interventions for VRUs should be made based on the analysis of temporal epidemiology and injury profiles of RTFs.