In situ measurement of isoprene in the marine air and surface seawater from the western North Pacific

Isoprene (2-methyl-1,3-butadiene) was measured on board of R/V Mirai for eight air samples and 14 seawater samples collected in the western North Pacific during ACE-Asia campaign (from 18 to 26 May 2001). The measurements were conducted in situ using a cryo-focus/gas chromatography/mass spectrometry (Cryo/GC/MS). Concentrations of isoprene ranged from 7.2 to 110 parts-per-trillion (pptv) in the marine air, and ranged from below 12 to 94 pmol l⁻¹ in the seawater. Based on these results, sea-to-air fluxes of isoprene were calculated to be 184 and 300 nmol m⁻² day⁻¹ for two samples, and the upper limits of the fluxes were also calculated to be from 32 to 300 nmol m⁻² day⁻¹. Atmospheric isoprene concentrations cannot be explained only by the flux from the seawater. Thus, the concentrations of isoprene in the marine air in western North Pacific should be significantly affected by terrestrial vegetational emission and subsequent long-range atmospheric transport of isoprene.     

Fate estimation of estrogenic substances in an urban river by flux calculation.

This study investigated the fate of estrogenic substances in an urban river receiving discharge from wastewater treatment plants (WTPs) by flux calculation, focusing on the middle reaches of the Tama River in Tokyo, which is one of the most urbanized rivers in Japan. The level of estrogenic activity flux was almost negligibly small at the upstream station. The level was considerably raised after inflows from the WTPs and then the level declined in the lower reaches of the river. When contributions of estrogenic substances to estrogenic activity were estimated, estrone (E1) was the primary contributor to the total estrogenic activity in all the sampling stations, followed by estradiol (E2). The contribution of nonylphenol to estrogenic activity was small. The E1 and E2 accounted for approximately 90% or more of estrogenic activity in the Tama River. As for the total fluxes of the estrogenic substances in the study area in the Tama River, the proportion of flux associated with WTP discharge was approximately 100% of the total fluxes, and the effects of the tributaries flowing into the river were almost negligible. When the reduction ratios of estrogenic activity were calculated by the flux, the ratios were found to increase toward the lower reaches of the river. Similar changes were observed for E1. Meanwhile, the change of reduction ratios for E2 was different from that observed for estrogenic activity.     

Germination test on Komatsuna (Brassica rapa var. peruviridis) seed using water extract from compost for evaluating compost maturity: evaluating criteria for germination and effects of cultivars on germination rate

Germination tests on the Komatsuna (Brassica rapa var. peruviridis) seed using water extract from compost has often been performed in Japan to evaluate compost maturity; however, most of the germination tests have been carried out without using any rationally defined experimental criteria to determine germination and to explain the influence of cultivars. Here, we performed a series of germination tests to examine the applicability of the experimental criteria for germination and the influence of cultivars on germination rate. Germination rate varied according to the criteria introduced in this paper, and two criteria, "seed size (3)" and "5?mm (2)", were selected for testing. In addition, two types of inhibitory influence, stop and slowness, were observed and compared with the criteria. The logistic regression curve of Logit, a function of germination rate to logarithmic value of the dilution ratio of the water extract was parameterized to compare the effects of the cultivars on germination rate. The statistical analysis of the parameters showed that dilution ratio greatly influenced germination rate, and the cultivar itself also influenced the rate. Consequently, the specific experimental criteria for germination and determining the influence of cultivars were proven to be indispensable for evaluating compost maturity using the germination test.     

Seasonal variability of radon-derived fetch regions for Sado Island,Japan, based on 3 years of observations: 2002–2004

Three years of hourly atmospheric radon measurements at Sado Island (Japan) are discussed and compared with corresponding measurements at Gosan (South Korea), and Hok Tsui (China). In conjunction with back trajectory analysis, Sado radon data are used to characterise the seasonal variability in fetch regions of air masses subject to extremes of terrestrial influence. In winter, fetch regions of air masses that have experienced the greatest terrestrial influence covered southern Siberia; in summer, the terrestrial fetch was dominated by Japan; throughout the remaining months the terrestrial fetch encompassed the Korean Peninsula and far eastern China. Summer radon data are then used to estimate the radon flux from central Honshu (23.5 mBq m^?2 s^?1), which varied regionally between 10.6 and 47.9 mBq m^?2 s^?1. The Sado radon record reported here completes a 4-site, multi-year dataset of hourly radon concentrations across East Asia and the central Pacific (spanning 16° of latitude), which constitutes a unique evaluation tool for transport and mixing schemes of atmospheric and chemical transport models.     

Characteristics of ambient C2–C11 non-methane hydrocarbons in metropolitan Nagoya,Japan

To understand the characteristics of non-methane hydrocarbon (NMHC) abundance in an urban air of Nagoya, one of the metropolitan areas of Japan, 48 species of C₂–C₁₁ NMHCs were measured with a measurement system, developed in this study, by using gas chromatography with flame ionization detection (GC/FID) continuously for one year from December 2003 to November 2004.Annual mean concentration of NMHCs in normal and propylene equivalent (PE) in Nagoya was compared with those in four urban areas of Seoul, London, Lille, and Dallas to extract characteristics of urban air. While the absolute values of the normal and PE concentrations of alkanes, alkenes, alkyne, and aromatics were significantly different among these urban areas, the proportions of each chemical group to the total NMHC were not so different.In Nagoya, the total normal concentration was high from November to February and low from June to August. The pattern of the seasonal variation was influenced mainly by that of alkanes. On the other hand, the total PE concentration was high from July to December and low from January to June. The pattern of the seasonal variation was influenced mainly by those of alkenes and aromatics. Particularly the normal concentration of isoprene was high from May to September because of large emission associated with activity of plants. As the results, in summer, the PE concentration of isoprene was especially high, and its contribution to the total NMHCs measured in this study was approximately 40%. The total PE concentrations were high in summer when the concentration of OH radicals is also high, suggesting that the productions of ozone and secondary organic aerosol (SOA) are likely to be promoted in summer of Nagoya.     

The Effect of Estrogens,River Water,and Treated Wastewater on Vitellogenin Induction of Japanese Medaka1

Abstract: The objective of this study is to evaluate the effect of estrogens on fish endocrine disruption in river water and treated wastewater. Endogenous estrogen estrone (E1), 17β‐estradiol (E2), river water, and treated wastewater were used for exposure tests on male Japanese medaka. Vitellogenin induction in male medaka was regarded as the endpoint of endocrine disruption. The effective concentrations of E1 and E2 on vitellogenin induction in medaka were evaluated by breeding medaka for 14 days in tanks with various concentrations of E1 or E2. Vitellogenin induction increased with elapse of time during exposure, with higher estrogen concentrations causing greater vitellogenin induction. According to the test results, the lowest observed effect concentrations (LOECs) of E1 and E2 were estimated to be 31.6 and 5.0 ng/l, respectively; and the E2 equivalent (EEQ) LOEC value of E1 was 5.2 ng‐E2/l, derived by multiplying the relative potency of E1 by that of E2 as estimated in this study. In continuous exposure tests using river water or treated wastewater, the estrogenic activity, an index of total estrogenic potential measured by yeast screen assay and expressed as EEQ, varied widely during the exposure tests, and significant vitellogenin induction was observed after several days of high levels of estrogenic activity in water. Vitellogenin concentration tended to significantly increase if EEQ exceeded the level of 5 ng‐E2/l. The threshold value was substantially the same as the results for E1 and E2 exposure tests of medaka. Consequently, EEQ over 5 ng‐E2/l was revealed to have the potential to cause endocrine disruption of male medaka. As estrogenic activity exceeding 5 ng‐E2/l was observed in some rivers in Japan, total estrogenic potential needs to be further decreased at wastewater treatment plants to prevent fish endocrine disruption.     

TEMPO-Mediated Oxidation of Hemp Bast Holocellulose to Prepare Cellulose Nanofibrils Dispersed in Water

Hemp bast holocellulose fiber (Cannabis sativa L. Subsp. Sativa) was oxidized by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation at various NaClO addition levels in water at pH 10. When carboxylate contents of the oxidized products were 1.5–1.7 mmol/g, TEMPO-oxidized cellulose nanofibrils almost completely dispersed at the individual nanofibril were obtained by mechanical disintegration of the TEMPO-oxidized hemp bast holocelluloses in water, where the nanofibrillation yields were 98–100 %. The sugar composition analysis revealed that most of hemicelluloses originally present in the hemp bast holocellulose were degraded and removed from the solid oxidized products, providing almost pure TEMPO-oxidized celluloses. X-ray diffraction patterns of all TEMPO-oxidized hemp bast holocelluloses had the same cellulose I crystal structure and similar crystallinity indices and crystal widths, indicating that carboxylate groups formed by the oxidation were selectively present on the crystalline cellulose microfibril surfaces in the holocellulose. However, the weight recovery ratios and viscosity-average degrees of polymerization of the TEMPO-oxidized hemp bast holocelluloses decreased to 69–59 % and 470–380, respectively, when their carboxylate contents increased to 1.5–1.7 mmol/g by the TEMPO-mediated oxidation. Atomic force microscopy height images showed that the nanofibril widths were 2.7–2.9 nm, and the average nanofibril lengths decreased from 590 to 400 nm as the NaClO addition level was increased from 7.5 to 12.5 mmol/g in the TEMPO-mediated oxidation.