Fumiyuki Asakawa

Investigation of Indoor Air Pollution by Chlorpyrifos : Determination of Chlorpyrifos in Indoor Air and 3,5,6-Trichloro-2-pyridinol in Residents' Urine as an Exposure Index

ObjectsWe carried out an investigation to clarify the real state of indoor air pollution by chlorpyrifos (termiticide) and exposure to chlorpyrifos of residents by measuring its urinary metabolite 3,5,6-trichloro-2-pyridinol (TCP) as an exposure index, such as biological monitoring.MethodsThe investigation was conducted in 43 individual houses with termiticide application (whether the termiticide was chlorpyrifos is uncertain) and 3 control houses without any termiticide application in Kagawa, Japan. Urine samples were collected from 46 healthy adult residents of the aforementioned houses.ResultsChlorpyrifos in indoor air in the control houses was not detected (ND<1 ng/m3, n=3), while 41 of 43 houses with termiticide application showed 1–350 ng/m3. Although the chlorpyrifos concentrations in these 41 houses did not exceeded the indoor air quality guideline of 1000 ng/m3, but 3 houses were higher than the guideline 100 ng/m3 for children in Japan. Urinary TCP concentrations of 0.1–7.8 ng/mg·creatinine were detected in 41 residents from the 41 houses where chlorpyrifos had been detected. The chlorpyrifos concentration and the urinary TCP revealed a positive correlation (r=0.5468, p<0.01, n=41).ConclusionsThe immediate health hazard from air born chlorpyrifos in the examined houses was negligible, but the findings suggest that it is necessary to monitor chemicals which may contaminate indoor air and to assess the risk of prolonged exposure to such chemicals. The measuring of urinary metabolite TCP of chlorpyrifos via biological monitoring would be useful, allowing comprehensive evaluation of the exposure to chlorpyrifos in indoor air.

A Method for On-Site Analysis of Urinary Benzene by Means of a Portable Gas-Chromatograph

Benzene is one of the toxic air pollutants released from automobile fuel, exhaust, tobacco smoke etc., and is commonly found in both indoor and outdoor air. Since benzene is a carcinogenic substance classified into group 1 (carcinogenic to humans) by the International Agency for Research on Cancer (IARC), it is important to assess the human health risk posed by exposure to environmental or occupational benzene. The analytical trials were performed to determine blood and urinary unchanged benzene as a specific index for low benzene exposure. But these methods require sophisticated and expensive instruments such as a gas chromatograph-mass spectrometer which can be used only in a laboratory. Moreover, benzene in biological fluids is volatilized so easily that it may cause the loss of samples during collection, transportation and preservation which is the most common cause of uncertainties. Therefore, the development of simple and specific methods to perceive benzene exposure are expected. In this study, we developed a method for on-site analysis of benzene in urine by head space-gas chromatography (HS-GC) employing a field portable GC, since on-site analysis can provide rapid data without time-consuming and loss-inducing processes such as transportation and preservation.

Chlordane compounds and metabolite residues in termite control workers' blood

Termites harm a wide range of materials, but they have a dominant predilection for wood. In Japan, where there are many wooden buildings, damages caused by termites are a major problem. Chlordane was used primarily as termiticides for extermination of termites and prevention of termite-caused damages. However, environmental contamination by Chlordane was later demonstrated (Miyazaki et al., 1980a; Miyazaki et al., 1980b; Yamagishi et al., 1981) as by other organic chlorine agricultural chemicals, i.e., DDT, BHC etc., and the use of Chlordane was prohibited in September, 1986.

Impact of Health Professionals on Health Promotion Activities in Japanese Worksites

Impact of Health Professionals on Health Promotion Activities in Japanese Worksites: Tomohiro Hirao, et al. Department of Hygiene & Public Health, Faculty of Medicine, Kagawa Medical University—We tried to assess the impact of health staff on health promotion activities in Japanese worksites. We surveyed all worksites with 50 or more employees in Kagawa Prefecture, western Japan through self‐administered questionnaires. We constructed a general linear model that contained three health professions, occupational physicians, health supervisors and occupational health nurses, which are common in the Japanese workplace as co‐regressors, and fourteen health promotion activities as dependent variables. The impact of occupational physicians was small. The impact of health supervisors was considered high in workplace defined activities. The impact of occupational health nurses was considered high in person‐to‐person services and life‐style related activities. Through assessing the impact, the strengths and weaknesses of each health professional were clarified.

Analysis of beta3 adrenergic receptor gene polymorphism using noninvasive samples obtained at scheduled infant health checkups.

Obesity is a risk factor for life-style-related diseases, and is based on three factors: genetic, environmental, and life-style. In adults, it is difficult to achieve and maintain normal body weight, so it is more effective to intervene from infancy to establish weight control. Legally required health checkups in infants of 18 and 36 months present important opportunities for obesity prevention. We consider genetic analysis to be a very important factor for obesity prevention in infancy. However, since health checkups don’t involve the collection of blood, genetic analysis is considered difficult. In this study, we attempted the typing of beta3 adrenergic receptor gene polymorphism as a genetic factor from non-invasively obtained samples, buccal mucosa, hair and cerumen in 96 infants at their 18- and 36-month health checkups. Sampling buccal mucosa, hair and cerumen instead of blood caused almost no anxiety to the child or parent, so 94.1% cooperation with sampling was obtained. From buccal mucosa, about 76% of the samples could be used for the typing of polymorphism (81% by enzyme method, 59% by kit method). From hair, about 44% of the samples permitted typing of polymorphism, but from cerumen only about 4% of the samples could be used. Results from buccal mucosa and hair typed about 90% of infant polymorphism. These results suggest that this method would be practical at periodic health checkups, and would probably be applicable to mass screenings for genetic factor analysis for other diseases.

Study on biological monitoring of fenpropathrin exposure in application by utilizing urinary 3-phenoxybenzoic acid level

To estimate pesticide exposure faced by applicators, an investigation of exposure-absorption was conducted on two applicators under routine working conditions and using regular procedures during pesticide spraying of greenhouse strawberries with fenpropathrin. The authors hypothesized that 3-phenoxybenzoic acid (3-PBA) is a urinary excreted metabolite of fenpropathrin, a synthetic pyrethroid pesticide with 3-phenoxybenzyl moiety, and its determination would help to improve the assessment of fenpropathrin exposure-absorption in applicators. The extent of exposure-absorption was evaluated by the determination of urinary level of 3-PBA (biological monitoring), the amount of the chemical adhered to clothes and permeated to the skin surface, and its concentration in the air of the greenhouse. The results showed that the fenpropathrin concentration in the air was less than 0.1 μg/m3. The amount of adhesion was less than 0.001 to 10.25 μg/cm2, and there was very little permeation. However, the urinary 3-PBA concentration by biological monitoring appeared to be approximately twice that of pre-exposure levels in both applicators. This finding demonstrates that the applicators were exposed to fenpropathrin and absorbed it during spraying. We conclude that the fenpropathrin exposure-absorption in application could be estimated by the determination of urinary 3-PBA. This method of biological monitoring may be more useful indicator to accurately evaluate the working conditions in application.

Possible sources of urinary benzene among nonoccupationally exposed Japanese subjects.

Unmetabolized benzene in urine (U-benzene) is known to be the best marker among the indices for the biological monitoring of occupational and environmental exposure to benzene. In this study, we determined the levels of U-benzene among Japanese university students exposed to benzene nonoccupationally and analyzed the relation between U-benzene levels and the possible factors responsible for environmental benzene exposure. In urinalysis, U-benzene concentration among 124 students was detected in the range from 18 (minimum detection limit) to 249 ng/l. The frequency distribution of U-benzene concentration peaked at 0–19 ng/l. Mean and median values of 40 and 20 ng/l for U-benzene concentration in nonoccupationally exposed subjects were lower than those in a previous study. Stepwise multiple linear regression analysis was performed to assess the potential sources of exposure to environmental benzene by analyzing the relation between U-benzene and personal, behavioral, and environmental factors. The results showed that only smoking habit (P < 0.01) and residential house age (P < 0.05) were independent determinants of U-benzene levels. In addition, U-benzene levels in relation to smoking and house age suggested that these factors could be associated with the synergistic elevation of U-benzene. The present study showed U-benzene levels among non-occupationally exposed Japanese subjects and revealed that the major exposure sources to benzene in the general environment were tobacco smoking and indoor air contamination.

Protective effect of D-psicose against testicular atrophy induced by di(2-ethylhexyl) phthalate

The pollutant di(2-ethylhexyl) phthalate (DEHP) is a suspected reproductive toxicant. To clarify the protective effect of D-psicose on DEHP-induced testicular atrophy, we exposed rats to 1% DEHP via their diet while receiving D-psicose supplementation. A significant negative correlation was found between plasma mono(2-ethylhexyl) phthalate (MEHP) concentrations and relative testicular weight in rats given the 1% DEHP-containing diet for seven days. There was, however, no significant difference in testicular weight compared with control in rats given the 1% DEHP-containing diet plus 2% D-psicose-supplemented water. Rats given the 1% DEHP-containing diet for 14 days showed severe testicular atrophy. Conversely, those given the diet plus 2 or 4% D-psicose-supplemented water did not develop testicular atrophy and exhibited complete spermatogenesis. Testicular weight was also restored almost completely by D-psicose. But, incomplete but significant protection was noted in rats receiving a 2% DEHP-containing diet plus 4% D-psicose-supplemented water for 14 days. The present study shows the almost complete protective effect of D-psicose against DEHP-induced testicular atrophy. Although the reproductive toxicity of DEHP in human beings remains unclear, D-psicose may act as a protective agent against oxidant-mediated testicular injury in mammals, including human beings.

Tissue concentrations of chlordanes in mice after long-term exposures to technical grade chlordane at indoor air levels

We determined concentrations of chlordanes (5 chlordane compounds and 2 metabolites) in tissues and organs of mice following a prolonged exposure to Chlordane (technical grade chlordane) at levels as low as those in indoor air.After exposure to 4.22–11.36 μ g/m3 Chlordane (total of 5 compounds) in the air for 1–6 months, 6.44–13.00 ppm chlordanes (total of 7 compounds) were detected in mice (2 tissues and 6 organs). The adipose tissue among the 2 tissues / 6 organs examined contained the highest chlordanes. The ratio of the adipose tissue chlordanes to the liver chlordanes was approximately 5.6 times, followed by the muscle (0.9), lungs (0.4), kidneys (0.4), heart (0.3), spleen (0.2) and brain (0.1). In addition, trans-nonachlor, oxychlordane and heptachlorepoxide in chlordanes were at a high level.The level of Chlordane exposure (dose) and the level of chlordanes accumulation in each tissue or organ of the mice except for the heart were closely correlated (r=0.9388-0.7130), and showed a linear relationship. The tendency of chlordanes accumulation in light of the linear relationship was adipose ≫ liver ≥ muscle.Thus, even with a low level of Chlordane in indoor air, chlordanes may be steadily accumulated in the bodies of human residents with prolonged exposure similarly. The present findings suggest that it is necessary to investigate die risk of organochlorine chemicals contamination in indoor air at prolonged exposure.