Formaldehyde is a carcinogen to which humans are exposed daily, but few methods are available to quantify formaldehyde in biological samples. We developed a simple, sensitive and rapid technique for the quantification of formaldehyde in urine by derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, using a headspace sampler coupled to a gas chromatograph equipped with an electron capture detector. The detection limit was 1.08 microg/L. The overall recovery of formaldehyde spiked in urine was 99%. The concentration of formaldehyde in urine obtained from healthy volunteers ranged from 56.85 to 144.57 microg/L. This method can be used successfully to measure formaldehyde in urine.

Unmetabolized VOCs in Urine as (VOCs) in urine as biomarkers of low-level indoor environmental exposure. Twenty-four subjects in 13 dwellings in a prefecture of Japan participated in this study. Air samples of the breathing zone were collected in the living room and bedroom, along with spot urine samples (before bedtime and first morning voids). Toluene, ethylbenzene, xylene isomers, styrene and pdichlorobenzene in the air and urine samples were measured by gas chromatography/mass spectrometry. For the 21 subjects without solvent exposure at work, there were significant correlations between the timeweighted average air concentrations in the bedroom and morning urinary concentrations for toluene, oxylene, total xylene and p-dichlorobenzene (correlation coefficients of 0.54, 0.61, 0.56 and 0.84, respectively). Multiple linear regression analysis showed only air VOCs in the bedroom influenced the morning urinary VOC concentrations. We concluded that unmetabolized VOCs in the urine can provide a reliable biological indicator for air VOC exposures in non-occupational environments. (J Occup Health 2007; 49: 104-110)

The Hishikari gold–silver deposits in southern Kyushu, Japan, are low‐sulfidation vein‐type epithermal deposits. Bulk composition analysis, fluid inclusion microthermometry and quantitative gas composition analysis on the basis of the crush‐fast scan (CFS) method were conducted to elucidate characteristics and behavior of hydrothermal fluids responsible for the gold mineralization of the Hishikari deposits. Quartz vein samples were collected from widely scattered locations of ore veins: Zuisen‐6, ‐3, ‐1 (Main deposit), Keisen‐2 and Shosen‐5 (Sanjin deposit), and Seisen‐8 (Yamada deposit) between −70 and 64 ML (mine meter level). The samples are composed mainly of quartz and adularia, and ore minerals of electrum, pyrargyrite, pyrite and/or stibnite, having an average bulk Ag/Au weight ratio of 0.54. Fluid inclusions in quartz and adularia are two‐phase liquid–vapor, and their trapping temperatures and salinities are ca. 190–220 °C and 1.5–2.7 wt.% NaCl eq., respectively. The salinity is highest with an average 2.4 wt.% NaCl eq. of the fluid inclusions from the deepest level (Zuisen‐6 vein at −70 ML), while the fluid inclusion salinities from other samples are relatively low less than ca. 2.0 wt.% NaCl eq. Parallel‐ and lattice‐bladed quartz occur in a number of veins, suggesting fluid boiling during the vein formation. Gases of fluid inclusions are composed mainly of H2O (93.4–99.8 mol%) and CO2 (0.15–6.2 mol%), N2 (0.007–0.96 mol%), Ar (0.0001–0.0047 mol%), CH4 (0.002–0.048 mol%), H2S (0.0004–0.0028 mol%), H2 (0–0.074 mol%) and He (0.0002–0.0011 mol%). CO2, N2 and Ar contents of the fluid inclusions are elevated in the samples collected from deep levels, while H2O, H2S and He contents are elevated in those from shallow levels. The Ar/He, CO2/CH4 and N2/Ar ratios of fluid inclusion gas indicate a systematic transition from magmatic to meteoric signatures in order from deep to shallow levels. The CO2/N2 ratio and volatiles contents are positively correlated suggesting condensation in relatively high Au‐grade quartz vein samples (19.5–27.7 ppm Au), while negative correlations suggest boiling with volatile contents less than 1% are indicative of low Au‐grade quartz vein samples (0.14 to 0.18 ppm Au). The elevated CO2 contents observed in the Zuisen veins are signatures of the deeply circulating hydrothermal fluid with a magmatic contribution. Due to intermittent boiling of hydrothermal fluid, CO2 and H2S were partitioned into the vapor phase in deeper portions and condensed into the steam‐heated meteoric water in shallower portions. The signatures of both meteoric and magmatic fluids in fluid inclusion gas compositions were detected in the samples collected near the unconformity between Shimanto Supergroup (shale and sandstone) and Hishikari Lower Andesite. This suggests that a mixing of the deeply circulating hydrothermal fluids with the steam‐heated meteoric water took place near the unconformity, and it was one of the mechanisms to have precipitated gold.

This study describes an ecological study that evaluated the combined effects of working hours, income, and leisure time on suicide in all 47 prefectures of Japan. In men, the age-adjusted rate of suicide (per 100,000 population) was significantly correlated with working hours (r=0.587, p<0.0001) as well as significantly and negatively correlated with income (r=−0.517, p=0.0002) and times for the leisure activities of self-education (r=−0.447, p=0.0016) and hobbies (r=−0.511, p=0.0002). In addition, a stepwise multiple regression analysis identified time for leisure social activities as a determining factor in suicide rate, even after adjusting for working hours and income. However, the impact of time for leisure social activities on suicide rate was smaller than that of working hours and income. In contrast, none of these factors affected suicide rate in women. These results suggest that increasing leisure time may be useful for preventing suicide among men in Japan.

A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry.