Fluxes of carbon dioxide, methane and nitrous oxide in two contrastive fringing zones of coastal lagoon, Lake Nakaumi, Japan

We measured fluxes of carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) simultaneously in two typical fringing zones, sandy shore and salt marsh, of coastal lagoon, Lake Nakaumi, Japan, in mid-summer 2003. Our aim was to quantify net the greenhouse gases (GHGs) fluxes and examine key factors, which control variation of the GHGs fluxes in the two sites. Net CO(2) and CH(4) fluxes were markedly different between the two sites; magnitudes and variations of the both fluxes in sandy shore were lower than those of salt marsh. Meanwhile, magnitude and variation of net N(2)O flux in the two sites were similar. In sandy shore, temporal and spatial variation of the three GHGs fluxes were highly controlled by water level fluctuation derived from astronomic tide. In salt marsh, spatial variation of the three GHGs fluxes were correlated with aboveground biomass, and temporal variation of CO(2) and CH(4) fluxes were correlated with soil temperature. The sum of global warming potential, which was roughly estimated using the observed GHGs fluxes, was ca. 174-fold higher in salt marsh than in sandy shore.     

Reaction mechanism and pathway for the hydrothermal electrolysis of organic compounds

In this study, hydrothermal electrolysis experiments using glucose (a biorelated substance) as a starting material were carried out using a specially designed autoclave at 250°C. We could understand the fundamental reaction behavior of glucose under these conditions through various kinds of experiments and product analyses. Another series of experiments using pressurized CO₂ as an electrolyte was conducted to discover whether it is possible to use CO₂ as an alternative electrolyte to the conventional KCl electrolyte, with a view to lowering the environmental impact of the process. It was found that pressurized CO₂ was useful as an environmentally friendly electrolyte, although there were still some problems in terms of the reaction efficiency.     

Distribution of polybrominated diphenyl ethers in Japanese autopsy tissue and body fluid samples

Brominated flame retardants are components of many plastics and are used in products such as cars, textiles, televisions, and personal computers. Human exposure to polybrominated diphenyl ether (PBDE) flame retardants has increased exponentially during the last three decades. Our objective was to measure the body burden and distribution of PBDEs and to determine the concentrations of the predominant PBDE congeners in samples of liver, bile, adipose tissue, and blood obtained from Japanese autopsy cases. Tissues and body fluids obtained from 20 autopsy cases were analyzed. The levels of 25 PBDE congeners, ranging from tri- to hexa-BDEs, were assessed. The geometric means of the sum of the concentrations of PBDE congeners having detection frequencies >50 % (ΣPBDE) in the blood, liver, bile, and adipose tissue were 2.4, 2.6, 1.4, and 4.3 ng/g lipid, respectively. The most abundant congeners were BDE-47 and BDE-153, followed by BDE-100, BDE-99, and BDE-28+33. These concentrations of PBDE congeners were similar to other reports of human exposure in Japan but were notably lower than concentrations than those reported in the USA. Significant positive correlations were observed between the concentrations of predominant congeners and ΣPBDE among the samples analyzed. The ΣPBDE concentration was highest in the adipose tissue, but PBDEs were distributed widely among the tissues and body fluids analyzed. The PBDE levels observed in the present study are similar to those reported in previous studies in Japan and significantly lower than those reported in the USA.     

An automatic monitor of formaldehyde in air by a monitoring tape method

An automatic monitor has been developed for measuring formaldehyde in air using a sensitive tape for formaldehyde. It is based on the color change of the tape on reaction with formaldehyde. The porous cellulose tape, containing silica gel as an absorbent and impregnated with the processing solution containing hydroxylamine sulfate, Methyl Yellow (pH indicator; pH 2.9-4.0, red-yellow), glycerin and methanol, was found to be a highly sensitive means of detecting formaldehyde and maintains a stable sensitivity. When the tape was exposed to a sample of air containing formaldehyde, the color of the tape changed from yellow to red. The degree of color change was proportional to the concentration of formaldehyde at a constant sampling time and flow rate, and it could be recorded by measuring the intensity of reflected light (555 nm). The tape could be used to detect down to 0.08 ppm (World Health Organization standard) of formaldehyde with a sampling time of 30 min and a flow rate of 100 mL min-1. Reproducibility tests showed that the relative standard deviation of response (n = 10) was 3.8% for 0.1 ppm formaldehyde. The monitor is simple, specific, capable of unattended operation and is recommended for both laboratory and field operation.     

Antiviral Activities of Hibiscus sabdariffa L. Tea Extract Against Human Influenza A Virus Rely Largely on Acidic pH but Partially on a Low-pH-Independent Mechanism

Food and Environmental Virology - Influenza A virus (IAV) infection is perennially one of the leading causes of death worldwide. Effective therapy and vaccination are needed to control viral...     

Future risk of dengue fever to workforce and industry through global supply chain

The primary vector of the dengue fever virus, the Aedes aegypti mosquito, is distributed across the tropical and sub-tropical latitudes; however, the area at risk of infection has been expanding steadily. This study aimed to identify the industries most vulnerable to the effects of dengue fever by 2030. The assessment was done by considering the international supply chain, with aspects such as the labor intensity, and the relevant geographical and socioeconomic aspects being taken into account. In addition, multi-regional input-output tables were employed to analyze the ripple effects of productivity losses resulting from workers contracting the disease. The results indicate that more than 10% of the workers involved in the supply chain of all the major industries in the United States (USA), China, Japan, and Germany could be considered at risk of contracting dengue fever by 2030. Moreover, the risk was even higher in India and Brazil, namely, more than 70%. The effect of widespread dengue fever infection could influence industrial activities severely, not only in the regions most at risk (India and Brazil) but also in the other regions (USA, Japan, and Germany). Labor-intensive industries, such as agriculture, fisheries, and the distribution sector are particularly at risk and will have to consider appropriate contingency measures. It is recommended that the downstream side of the supply chain, the industries in the USA, Japan, and Germany, supports the introduction of worker’s health management system against the infectious disease into their business partners. This study employed limited data and only estimated the possible effects of the disease by 2030. Further comprehensive analysis is required with more data modeled for the future to verify and enhance the reliability of the present results.     

Embryonic development assay with Daphnia magna: application to toxicity of aniline derivatives.

An assay system using Daphnia magna embryos was applied to investigate the adverse effects of aniline derivatives. The data were compared with our previous data for chlorophenols. This new assay provides useful information to evaluate the toxicity of chemicals and the differences in sensitivity between the life stages. The effects of 15 aniline derivatives on embryonic development of D. magna embryos were determined. At the start of exposure, 2-6-h old eggs (between stages 1 and 2, round in shape, diameter approx. 400 microm), were used. In control and solvent control groups, embryonic development from an egg to a free-swimming animal proceeded completely within 3 days with more than 90% hatchability. Median effective concentrations (EC50s) to reduce the numbers hatched were determined and gross morphological abnormalities of hatched animals recorded. Anilines induced no obvious morphological abnormalities and no developmental delay although premature deaths occurred. However, they affected the number of embryos hatching in a dose-dependent manner. In addition, this embryo assay was more sensitive to aniline derivatives (except for aniline) than acute juveniles immobilization assay. Ratios of 48-h EC50 (juvenile)/3-day EC50 (embryo) for eight anilines were greater than 5.0. Particularly, the ratios of 4-methyl-, 4-ethyl- and 3-methylaniline were 77, 23 and 11, respectively. EC50s for embryos and juveniles were poorly correlated (r = 0.41). This indicated that the sensitivities of the two life stages were different to the effects of anilines. EC50s were poorly correlated (r = -0.097) with the log Kow (1-octanol/water partition coefficient). These results were compared with previous results for phenols.     

A Mechanical Model for Sieving of Large Deposited Atmospheric Particulates in Surface Soil

A mechanical model for analyzing the sieving of large particulates in soil is proposed and a procedure for assessing soil contamination by airborne hazardous particulates is discussed. The model proposes that deposition of airborne particulates in soil is the results of transport processes of particulates in surface soil. The mechanical sieving of particulates is due to (a) trapping of particulates by the constricted necks of soil pores, (b) adhesion of particulates to pore walls, and (c) suspension in soil water. The probability of particulates being sieved is determined by the cumulative frequency of pore size distribution of the soil. The proposed model indicated that more than 95% of the falling particulates were sieved in the top 5 cm of the surface soil. Furthermore, the model estimated that the unrecorded initial fall of ¹³⁷Cs associated with contaminated particulates was in the range of 2229–2310 kBqm⁻² d⁻¹ and that the unrecorded initial depositions in the 1-cm surface layer were in the range from 129 to 135 kBqkg⁻¹ at a location of about 30 km from the Fukushima nuclear power plant.

     

Monitoring OH-PCBs in PCB transport worker’s urine as a non-invasive exposure assessment tool

In this study, we analyzed hydroxylated polychlorinated biphenyls (OH-PCBs) in urine of both PCB transport workers and PCB researchers. A method to monitor OH-PCB in urine was developed. Urine was solid-phase extracted with 0.1% ammonia/ methanol (v/v) and glucuronic acid/sulfate conjugates and then decomposed using β-glucuronidase/arylsulfatase. After alkaline digestion/derivatization, the concentration of OH-PCBs was determined by HRGC/HRMS-SIM. In the first sampling campaign, the worker’s OH-PCB levels increased several fold after the PCB waste transportation work, indicating exposure to PCBs. The concentration of OH-PCBs in PCB transport workers’ urine (0.55~11 μg/g creatinine (Cre)) was higher than in PCB researchers’ urine (< 0.20 μg/g Cre). However, also a slight increase of OH-PCBs was observed in the researchers doing the air sampling at PCB storage area. In the second sampling, after recommended PCB exposure reduction measures had been enacted, the worker’s PCB levels did not increase during handling of PCB equipment. This suggests that applied safety measures improved the situation. Hydroxylated trichlorobiphenyls (OH-TrCBs) were identified as a major homolog of OH-PCBs in urine. Also, hydroxylated tetrachlorobiphenyls (OH-TeCBs) to hydroxylated hexachlorobiphenyls (OH-HxCBs) were detected. For the sum of ten selected major indicators, a strong correlation to total OH-PCBs were found and these can possibly be used as non-invasive biomarkers of PCB exposure in workers managing PCB capacitors and transformer oils. We suggest that monitoring of OH-PCBs in PCB management projects could be considered a non-invasive way to detect exposure. It could also be used as a tool to assess and improve PCB management. This is highly relevant considering the fact that in the next 10 years, approx. 14 million tons of PCB waste need to be managed. Also, the selected populations could be screened to assess whether exposure at work, school, or home has taken place.