Emiko Todaka

Necessity to Measure PCBs and Organochlorine Pesticide Concentrations in Human Umbilical Cords for Fetal Exposure Assessment

Three types of tissue samples—umbilical cord (UC), umbilical cord serum (CS), and maternal serum (MS)—have often been used to assess fetal exposure to chemicals. In order to know the relationship of contamination between mothers and fetuses, we measured persistent chemicals in comparable sets of the three tissue samples. Also, we analyzed the association between the chemicals in maternal and fetal tissues to know which tissue is the best sample for fetal exposure assessment. On a wet basis, the chemical concentrations were of the order MS > CS > UC, except for some chemicals such as cis-chlordane and endosulfan. On a lipid basis, the concentrations in UC were nearly equal or often higher than in MS, but the concentrations in CS were usually lower than in others. Hexachlorocyclohexanes and penta-, hexa-, and heptachlorinated biphenyls showed an association between the concentrations in UC versus MS, and UC versus CS. These chemicals also showed high correlation coefficients between the chemical concentrations in UC of first babies and maternal age. These chemicals were closely related to each other when grouped on the basis of their concentrations using cluster analysis. In conclusion, we insist that UC is the best sample to assess fetal contamination status of persistent chemicals. There is a possibility that the assessment based on the contamination levels in CS result in an underestimation.

The Influence of Environmental Exposure to Formaldehyde in Nasal Mucosa of Medical Students during Cadaver Dissection

BACKGROUND Environmental exposure to formaldehyde is commonly associated with clinical symptoms such as mucosal irritation and olfactory disorders. However, the impact of such exposure on the development of mucosal inflammation and its outcome has not been carefully evaluated. METHODS The observational non-comparative study was planned. The study population consisted of group of 41 medical students who had signed up for a cadaver dissection course as part of their gross anatomy teaching at the school of medicine Chiba University in Japan. During such dissection course, the students are exposed to variable levels of environmental formaldehyde routinely employed for the preservation the cadavers. The subjects were evaluated by a detailed medical examination. We measured their serum IgE levels. In addition, an olfaction test and nasal mucosal sensitivity to histamine was serially determined, immediately before and after the course and 6 months after the completion of the course. RESULTS Olfactory abnormalities were observed in 13/41 (32%) subjects and increased nasal mucosal hypersensitivity to histamine was observed in 17/41 (41%) during and immediately after completion of the course. These subjects had evidence of preexisting allergic rhinitis. 6/41 (15%) other students with no prior evidence of allergic rhinitis also exhibited formaldehyde associated clinical symptoms during the dissecting course. However, the symptoms disappeared upon completion of the course in all subjects studied. CONCLUSIONS Temporary abnormalities in the olfaction test and increased nasal mucosal hypersensitivity to histamine were observed in a few students with preexisting allergic rhinitis after environmental exposure of high concentrations of formaldehyde. These effects appeared to be transient.

Correlation between human maternal-fetal placental transfer and molecular weight of PCB and dioxin congeners/isomers.

Establishing methods for the assessment of fetal exposure to chemicals is important for the prevention or prediction of the childs future disease risk. In the present study, we aimed to determine the influence of molecular weight on the likelihood of chemical transfer from mother to fetus via the placenta. The correlation between molecular weight and placental transfer rates of congeners/isomers of polychlorinated biphenyls (PCBs) and dioxins was examined. Twenty-nine sample sets of maternal blood, umbilical cord, and umbilical cord blood were used to measure PCB concentration, and 41 sample sets were used to analyze dioxins. Placental transfer rates were calculated using the concentrations of PCBs, dioxins, and their congeners/isomers within these sample sets. Transfer rate correlated negatively with molecular weight for PCB congeners, normalized using wet and lipid weights. The transfer rates of PCB or dioxin congeners differed from those of total PCBs or dioxins. The transfer rate for dioxin congeners did not always correlate significantly with molecular weight, perhaps because of the small sample size or other factors. Further improvement of the analytical methods for dioxin congeners is required. The findings of the present study suggested that PCBs, dioxins, or their congeners with lower molecular weights are more likely to be transferred from mother to fetus via the placenta. Consideration of chemical molecular weight and transfer rate could therefore contribute to the assessment of fetal exposure.

Strong correlation between the concentration of dioxins and total PCBs in current Japanese people

The purpose of this study was to establish an economic and efficient method to screen total PCBs and total dioxins (PCDDs+PCDFs+Co-PCBs) in the highly exposed people in Japan. In this paper, we suggest use of total PCBs in human blood to represent other persistent organic pollutants, especially dioxins. Twenty blood samples were collected from Japanese volunteers. Total PCBs and total dioxins (PCDDs+PCDFs+Co-PCBs) were detected from all twenty blood samples. We carried out detailed analysis of correlation between concentration of total PCBs and each dioxin congener with both measured value and TEQ calculated value. The mean concentration of total PCBs was 250 ng g-fat(-1), and the mean concentration of total dioxins was 37 ng g-fat(-1) or 40 pg TEQ g-fat(-1). Correlations between the total PCBs (ng g-fat(-1)) and the total measured dioxins (ng g-fat(-1)), and between the total PCBs (ng g-fat(-1)) and the total dioxin TEQ calculated value (pg-TEQ g-fat(-1)) were 0.95 and 0.90, respectively. It became clear that the concentrations of total PCBs in human blood is a good indicator of the concentrations of total dioxins in Japan. If a mass screening is conducted on women of reproductive age in order to detect highly exposed women, it is possible that women with the highest contamination may be treated in order to decrease the levels of these chemicals before pregnancy. In conclusion, measurement of total PCBs concentration is useful for exposure assessment of dioxins in human blood.

Correlating the symptoms of sick-building syndrome to indoor VOCs concentration levels and odour

Sick-building syndrome (SBS) is a range of symptoms such as eye irritation, sore throat, and headaches that occur when entering a newly constructed or refurbished building. Volatile organic compounds (VOCs) are suspected to be one of the major causes of SBS. However, although Ministry of Health, Labour, and Welfare of Japan set the guideline values for 13 VOCs, the incidences of SBS patients have not decreased. In addition, there have been reports that when people complained symptoms of SBS, most of them also claimed to smell an odour. Furthermore, the occurrence of SBS symptoms depends largely on the person’s sensitivity. In this study, the correlation between the sum of VOCs(C2-C16) including aldehydes (ΣVOCs) and SBS symptoms were examined by statistics. The odour was quantified using the odour threshold ratio (OTR) and the correlation between the total odour threshold ratio (TOTR: sum of the OTR) and SBS symptoms was investigated. These correlations were examined separately for sensitive and insensitive groups. TOTR and the concentration level of ΣVOCs were correlated with SBS symptoms among sensitive people. The findings indicate that TOTR, in addition to ΣVOCs, could be used as a new risk indicator for human health regarding indoor air quality.

Chiba study of Mother and Children's Health (C-MACH): cohort study with omics analyses

Purpose Recent epidemiological studies have shown that environmental factors during the fetal period to early childhood might affect the risk of non-communicable diseases in adulthood. This is referred to as the developmental origins of health and disease (DOHaD) concept. The Chiba study of Mother and Childrens Health (C-MACH) is a birth cohort study based on the DOHaD hypothesis and involves multiomics analysis. This study aims to explore the effects of genetic and environmental factors—particularly the fetal environment and postbirth living environment—on childrens health, and to identify potential biomarkers for these effects. Participants The C-MACH consists of three hospital-based cohorts. The study participants are pregnant women at <13 weeks gestation. Women who underwent an examination in one of the three hospitals received an explanation of the study. The participants consented to completing questionnaire surveys and the collection and storage of biological and house/environmental samples. Participants were provided unique study numbers. All of the data and biological specimens will be stored in the Chiba University Center for Preventive Medical Sciences and Chiba University Center for Preventive Medical Sciences BioBank, respectively. Findings to date Consent to participate was obtained from 433 women. Of these women, 376 women completed questionnaires in the early gestational period. The mean age was 32.5 (4.4) years. The mean body mass index (BMI) was 21.1 (3.0) kg/m2. Before pregnancy, 72.3% of the women had a BMI of 18.5–24.9 kg/m2. During early pregnancy, 5.0% of the participants smoked. Future plans Primary outcomes are allergy, obesity, endocrine and metabolic disorders, and developmental disorders. Genome-level, metabolome-level, umbilical cord DNA methylation (epigenome), gut microbiota and environmental chemical exposure variables will be evaluated. We will analyse the relationships between the outcomes and analytical variables.

Establishment of sustainable health science for future generations: from a hundred years ago to a hundred years in the future.

Recently, we have investigated the relationship between environment and health from a scientific perspective and developed a new academic field, “Sustainable Health Science” that will contribute to creating a healthy environment for future generations. There are three key points in Sustainable Heath Science. The first key point is “focusing on future generations”—society should improve the environment and prevent possible adverse health effects on future generations (Environmental Preventive Medicine). The second key point is the “precautious principle”. The third key point is “transdisciplinary science”, which means that not only medical science but also other scientific fields, such as architectural and engineering science, should be involved. Here, we introduce our recent challenging project “Chemiless Town Project”, in which a model town is under construction with fewer chemicals. In the project, a trial of an education program and a health-examination system of chemical exposure is going to be conducted. In the future, we are aiming to establish health examination of exposure to chemicals of women of reproductive age so that the risk of adverse health effects to future generations will decrease and they can enjoy a better quality of life. We hope that society will accept the importance of forming a sustainable society for future generations not only with regard to chemicals but also to the whole surrounding environment. As the proverb of American native people tells us, we should live considering the effects on seven generations in the future.

Maternal–fetal transfer rates of PCBs, OCPs, PBDEs, and dioxin-like compounds predicted through quantitative structure–activity relationship modeling

The present study aims to predict the maternal–fetal transfer rates of the polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), and dioxin-like compounds using a quantitative structure–activity relationship model. The relation between the maternal–fetal transfer rate and the contaminants’ physicochemical properties was investigated by multiple linear regression (MLR), partial least square regression (PLS), and random forest regression (RF). The 10-fold cross-validation technique estimated low predictive performances for both MLR and PLS models (R2CV = 0.425 ± 0.0964 for MLR and R2CV = 0.492 ± 0.115 for PLS) and is in agreement with an external test (R2pred = 0.129 for MLR and R2pred = 0.123 for PLS). In contrast, the RF model exhibits good predictive performance, estimated through 10-fold cross-validation (R2CV = 0.566 ± 0.0885) and an external test set (R2pred = 0.519). Molecular weight and polarity were selected in all models as important parameters that may predict the ability of a molecule to cross the placenta to the fetus.

Aldehyde emissions from lime plaster containing vegetable oil

Lime plaster applied to walls and ceilings often contains vegetable oil for improving water resistance, and is considered to be harmless owing to its natural origin. The purpose of this study was to assess aldehyde emissions from plaster containing vegetable oil in order to predict the concentrations of aldehydes emitted into the indoor air. A passive emission chamber method was used to observe the emissions of aldehydes from vegetable oil when mixed with sodium hydroxide solution. The findings show that the alkalinity of calcium hydroxide in the plaster would accelerate the formation of aldehydes significantly. Furthermore, aldehyde emissions from the plaster to which vegetable oil was added were tested using a dynamic emission chamber (the small chamber method). A plaster containing soybean oil strongly emitted hexaldehyde throughout the test period. Plasters containing linseed oil or perilla oil strongly emitted propionaldehyde and acetaldehyde. The calculated indoor air concentrations of the aldehydes emitted from the lime plasters containing vegetable oil exceeded the air quality guidelines of the Japanese Ministry of Health, Labour, and Welfare, the Japanese Ministry of the Environment, and the German Federal Environmental Protection Agency. Moreover, these aldehydes are irritants and have unpleasant odours. Therefore, adding vegetable oil to plaster should be avoided to prevent sick-building syndrome.

An experimental trial to establish risk communication as a tool to decrease the risk by exposure to multiple chemicals for the future generations

BackgroundRecently, it has become clear that fetuses are exposed to multiple chemicals and environmental contaminants. However, it has been reported that allergies among young children have been increasing rapidly in the last few decades, and some congenital anomalies are also increasing. There is no evidence to connect these facts directly, however if adverse health effects are caused by environmental reasons, it could be prevented by early education or risk communication.MethodsThe authors gave lectures to students at a high school and universities, and carried out a questionnaire survey before and after the lectures to see the change of the students’ knowledge, attitude and behavior. The total number of high-school students and university students was 47 and 605, respectively.ResultsIt became clear that all the levels of knowledge, attitude and behavior were elevated, and they were more elevated among high school students than university students. It was suggested that risk communication at a younger age is important to elevate people’s attention and motivate them, and eventually prevent their future health risk from environmental contaminants.ConclusionRisk communication at a young age would be more effective in increasing students’ knowledge, attitude and behavior.