Actual Exposure Research Articles

Risk assessment for o-toluidine and bladder cancer incidence.

Elevated bladder cancer incidence has been reported in a cohort of 1875 workers manufacturing chemicals used in the rubber industry and employed any time during 1946-2006. o-Toluidine (OT), an aromatic amine, was the prime suspect agent. Using the available environmental data and process characterization, previous investigators assigned ranks to volatile chemical air concentrations across time in departments and jobs, reflecting probabilities of exposure and use of personal protective equipment for airborne and dermal exposures. Aniline, another aromatic amine, was present at comparable concentrations and is known to be an animal carcinogen but produced lower levels in post-shift urine and of hemoglobin adducts than OT in a group of workers. A quantitative risk assessment was performed based on this same population. In this study, cumulative OT exposures were estimated (a) based on previously assigned ranks of exposure intensity and reported actual exposures in jobs with the highest assigned rank, and (b) directly from the historical environmental sampling for OT. Models of bladder cancer incidence were evaluated taking into account possible healthy worker survivor effects. Under various assumptions regarding workforce turnover, the excess lifetime risk of bladder cancer from OT exposure at 1 ppb was estimated to be in the range 1-7 per thousand. The current ACGIH TLV and OSHA standards for OT are 2 and 5 ppm, respectively, 1000-fold higher than the exposure estimated here for 1-7 per thousand excess lifetime risk.

Mixtures of persistent organic pollutants are found in vital organs of late gestation human fetuses

Persistent organic pollutants (POPs) are industrial chemicals with long half-lives. Early life exposure to POPs has been associated with adverse effects. Fetal exposure is typically estimated based on concentrations in maternal serum or placenta and little is known on the actual fetal exposure. We measured the concentrations of nine organochlorine pesticides (OCPs), ten polychlorinated biphenyl (PCB) congeners, and polybrominated diphenyl ether (PBDE) congeners by gas chromatography – tandem mass spectrometry in maternal serum, placenta, and fetal tissues (adipose tissue, liver, heart, lung and brain) in 20 pregnancies that ended in stillbirth (gestational weeks 36–41). The data were combined with our earlier data on perfluoroalkyl substances (PFASs) in the same cohort (Mamsen et al. 2019). HCB, p,p’-DDE, PCB 138 and PCB 153 were quantified in all samples of maternal serum, placenta and fetal tissues. All 22 POPs were detected in all fetal adipose tissue samples, even in cases where they could not be detected in maternal serum or placenta. Tissue:serum ratios were significantly higher in later gestations, male fetuses, and pregnancies with normal placental function. OCPs showed the highest tissue:serum ratios and PFAS the lowest. The highest chemical burden was found in adipose tissue and lowest in the brain. Overall, all studied human fetuses were intrinsically exposed to mixtures of POPs. Tissue:serum ratios were significantly modified by gestational age, fetal sex and placental function. Importantly, more chemicals were detected in fetal tissues compared to maternal serum and placenta, implying that these proxy samples may provide a misleading picture of actual fetal exposures.

Street view greenness is associated with lower risk of obesity in adults: Findings from the 33 Chinese community health study

BackgroundUrban greenness may protect against obesity, but very few studies have assessed ‘street view’ (SV) greenness metrics, which may better capture people's actual exposure to greenness compared to commonly-used satellite-derived metrics. We aimed to investigate these associations further in a Chinese adult study. MethodsOur analysis included 24,845 adults in the 33 Chinese Community Health Study in 2009. SV images from Tencent Map, segmented by machine learning algorithms, were used to determine the average proportion of green vegetation in SV images at community level in 800m road network buffer. Sensitivity analyses were performed with an alternative buffer size. Overall greenness was assessed as normalized difference vegetation index (NDVI) in 800 m buffer. We used predicted PM2.5 and monitored NO2 as proxies of air pollution. Body mass index (BMI), waist circumference (WC) and hip circumference (HC) were regressed on SV greenness by generalized linear mixed models, with adjustment for covariates. Mediation analyses were performed to assess the mediation effects of air pollution. ResultsEach interquartile range (IQR = 3.6%) increase in street view greenness was associated with a 0.15 kg/m2 (95% CI: −0.22, −0.09) decrease in BMI and 0.23 cm (95% CI: −0.35, −0.11) reduction in HC, and was associated with 7% lower odds of overweight (OR = 0.93, 95% CI:0.90, 0.96) and 18% lower odds of obesity (OR = 0.82, 95% CI:0.76, 0.89). Similar effect estimation was observed compared with commonly-used NDVI measures. PM2.5 and NO2 mediated 15.5% and 6.1% of the effects of SV greenness with BMI, respectively. ConclusionsOur findings suggest beneficial associations between community-level SV greenness and lower body weight in Chinese adults. The effects were observed in women but not in men. Air pollution may partially mediate the association. These findings may have implications to support efforts to promote greening in urban areas.

Hsa_circ_0005915 promotes N,N-dimethylformamide-induced oxidative stress in HL-7702 cells through NRF2/ARE axis

N,N-dimethylformamide (DMF) is an organic compound widely used in industrial production processes as a solvent with a low evaporation rate. Excessive exposure to DMF may lead to liver damage. Oxidative stress has been reported as one of the main causes of DMF-induced hepatotoxicity. Several doses of DMF (0, 1, 5, and 10 mM) were used to treat HL-7702 cells for a relatively long period to simulate the actual exposure pattern in occupational settings, and oxidative stress was induced. Previous studies illustrated that circular RNA (circRNA) plays a vital role in sustaining hepatocyte physiological function. To explore whether aberrant circRNA expression is involved in DMF-induced excessive ROS generation and hepatotoxicity, high-throughput transcriptional sequencing was performed to identify the altered circRNA expression profiles in HL-7702 liver cells after treatment with 0, 75, or 150 mM DMF for 48 h. We found that levels of induced oxidative stress were similar to those in the long-term exposure model. Among the altered circRNAs, one circRNA (hsa_circ_0005915) was significantly upregulated after DMF exposure, and it affected DMF-mediated oxidative stress in HL-7702 cells. Further experiments revealed that hsa_circ_0005915 downregulated the expression of nuclear factor erythoid-2-related factor 2 (NRF2) at the post-transcriptional level via promoting the ubiquitination and degradation of NRF2, which led to the increase of ROS accumulation. Further investigation demonstrated that the expression levels of NRF2-regulated antioxidative genes—heme oxygenase 1 (HO1) and NAD(P)H quinone dehydrogenase 1 (NQO1)—indeed declined after the overexpression of hsa_circ_0005915. In vivo study also indicated that DMF exposure can upregulate the expression of mmu_circ_0007941 (homologous circRNA of hsa_circ_0005915) and downregulated Nrf2 and Ho1 proteins. In summary, our results revealed that hsa_circ_0005915 plays an important role in promoting DMF-induced oxidative stress by inhibiting the transcriptional activity of the NRF2/ARE axis, which provides a potential molecular mechanism of DMF-mediated hepatotoxicity.

Individual and combined effects of BPA, BPS and BPAF on the cardiomyocyte differentiation of embryonic stem cells

Exposure to many kinds of bisphenols (BPs) is common, and the effects of BP mixtures may differ from those of individual BPs. Therefore, evaluating combined exposure effects is necessary. Our study evaluated the individual and combined exposure effects of bisphenol A (BPA), bisphenol S (BPS) and bisphenol AF (BPAF) on embryonic development using an embryonic stem cell test (EST) and a concentration additive (CA) model at relatively high doses to uncover the interaction model of the three BPs. Environmentally relevant concentrations were then used to evaluate the possible effects of the individual and combined BPs at actual human exposure levels. Exposure to relatively high-dose BPA, BPS and BPAF inhibited embryonic stem cell differentiation into cardiomyocytes and exhibited weak embryo toxicity. Individually, BPA, BPS and BPAF inhibited endoderm, mesoderm and ectoderm marker expression but enhanced pluripotency marker expression. Combined exposure to BPs had an additive effect on cardiomyocyte differentiation and embryonic stem cell proliferation based on the CA model. Environmentally relevant individual or combined BP doses (10 ng/ml individual BPA, BPS and BPAF doses or 1 ng/ml and 10 ng/ml BP mixture doses) failed to cause oxidative stress, DNA damage or apoptosis changes in stem cell differentiation. The cardiomyocyte differentiation ratio also did not change significantly. Individual and combined exposure to environmentally relevant BP doses led to a significant increase in collagen expression. BPAF and the combination of BPs increased the type 1 collagen level, while the combination also increased the type 3 collagen level, which may be related to p38 pathway activation. The p38 pathway inhibitor SB203580 inhibited the increase in collagen during cardiomyocyte differentiation caused by low-dose BPs. These results suggest that relatively high-dose BPs in combination have an additive effect on cardiomyocyte differentiation. Low-dose BPs individually and in combination may affect cardiomyocyte collagen through the p38 pathway.

The impact of nocturnal road traffic noise, bedroom window orientation, and work-related stress on subjective sleep quality: results of a cross-sectional study among working women

ObjectiveTo examine the effect of work-related stress and road noise exposure on self-rated sleep and potential additive interaction effects.MethodsSleep and predictor variables were surveyed within two subsamples with 2191 and 1764 working women in a cross-sectional study. Sleep was assessed using a single question on general sleep quality and four questions on specific sleep problems and subsequently dichotomized (poor sleep vs. no poor sleep). Work-related stress was operationalized by job strain and effort-reward imbalance. Nocturnal exposure to road traffic noise was assessed as (a) the orientation of the bedroom window to a quiet façade vs. a low-, medium- or high-trafficked street and (b) energy-equivalent sound pressure levels for night-time modelled at the most exposed façade (Lnight). We distinguished between low (< 45 dB(A)), medium (45–50 dB(A)) and high exposure (> 50 dB(A)).ResultsPoor sleep was associated with job strain and effort-reward imbalance. The prevalence of poor sleep did not increase with increasing Lnight, but bedroom window orientation showed a non-significant trend. A quiet façade had a protective effect on sleep in each Lnight category. We found a non-significant trend for an additive interaction between bedroom window orientation and job strain.ConclusionNoise levels modelled for the most exposed façade likely overestimate the actual exposure and thus may not be a precise predictor of poor sleep. Bedroom window orientation seems more relevant. Potential additive interaction effects between bedroom window orientation and job strain should be considered when interpreting epidemiological study results on noise-induced sleep disturbances.

Investigations of radiation exposures in the aftermath of the Chernobyl accident

Long-term assessment of the aftermath of the Chernobyl and Fukushima accidents deals with the study of radionuclide emissions and radiation exposure in heavily polluted regions. A signifcant difference in the composition and nature of radionuclide emissions during accidents at nuclear power plants is considered in the study - a largescale radioactive fallout transfer and precipitation over the USSR and Europe took place in Chernobyl due to the uncovered core of the reactor while at Fukushima a massive emission of inert gases occurred. It is noted that based on the density of precipitation, the data indicating that the vital doses of 137Cs remain signifcantly lower or within the range of natural radiation exposure were obtained. However, due to a short half-life (8.0 days) of 131I, there are no available comprehensive measurements of 131I exposure after the accident. It is noted that retrospective dosimetry of the effect of 131I on the thyroid gland through 129I with a half-life of 15.7 Ma allows to fll the gap in this issue. 137Cs precipitation was analyzed by gamma spectrometry, 129I was studied by accelerating mass spectrometry in soil samples from 60 places in zones II and III in the north of Ukraine and the thyroid gland radiation dose in the population. Critical comparing of the results obtained with those of rare direct measurements of 131I activity in the human thyroid gland reveal that the doses are at the lower limit. The actual radiation exposure in the contaminated regions of Northern Ukraine was considered by estimating the exposure dose in returnees in the village of Khrystynivka where 30 families live and consume locally produced products in the evacuated zone II, 75 km from the Chernobyl NPP. The results show that the additional irradiation with 137Cs the returnees received was low. The possibility of safe living in heavily polluted areas is noted. Under the normal way of life, the total radiation exposure of Khrystynivka village residents was within the natural radiation exposure range. Key words: radioactive fallout, radiation exposure, radiation pollution, irradiation of returnees.

Statistical evaluation of vertical and lateral temperature gradients in concrete box-girders

Atmospheric thermal loads are considered as one of the effective loads on bridge structures. The thermal actions in bridge superstructures are considered in most of the recent bridge design specifications. In this study, a concrete girder segment was cast in place in an open field to simulate the actual atmospheric exposure case of bridge girders. Inside and close the surfaces of the webs and flanges of the girder 62 thermocouples were distributed to measure the concrete temperatures in different sectional locations. In addition, the experimental field was provided with a compact weather station that records the three main influential atmospheric loads, which are the solar radiation and the temperature and speed of the field’s air. The experimental data from all sensors were recorded for a one-year that considers the variation of loads in the four seasons. The effective maximum temperature gradients, both vertically (along the depth of webs) and horizontally (along the width of flanges), were statistically correlated to the atmospheric loads and their derivatives. Nonlinear correlations were introduced to estimate the maximum gradients with determination coefficients of 0.92 to 0.96. The maximum errors between the experimental and predicted temperatures for the whole investigated period were in general less than 3.0 °C. The obtained correlations for the lateral gradients were more complicated than for the vertical gradient due to the effect of other parameters like the day index, which is related to the striking angle of solar radiations.

Carbon Dioxide Inhalation Mitigates Functional Deficits Elicited by Blast‐Induced Traumatic Brain Injury

Traumatic Brain Injury (TBI) is a significant public health burden affecting nearly 3 million individuals within the US alone annually. Large amounts of research dollars have been spent attempting to ameliorate the effects of TBI, however these efforts have failed to reduce injury rates or minimize the effects of primary injury incurred during activities such as contact sports or active military deployment. Preclinical and clinical work has revealed that mitigating brain SLOSH during cranial rotation or impact provides a profound protective effect against the effects of TBI. The biologic mechanism behind SLOSH mitigation is a filling of the compensatory reverse volume (CRV) of the skull, an effect that minimizes brain movement and the imparting of external forces on brain tissue. The most powerful biologically controllable determinant of CRV and intracranial pressure (ICP) is partial pressures of carbon dioxide (CO2, pCO2) within the bloodstream. We hypothesize that increased CO2 inhalation acting to minimize the CRV acts to minimize SLOSH and is therefore protective in the context of TBI. To initiate testing this hypothesis, we have combined increased environmental CO2 exposure with a murine model for blast-induced TBI. Murine subjects exposed to 5% CO2 for a period of 10 min in an environmental exposure chamber prior to TBI or sham treatments exhibited an increase in freezing behavior, indicative of actual exposure to gas composition, as compared to their medical grade atmospheric air counterparts. TBI treatment resulted in a significant increase in righting reflex time (RRT) as compared to sham treatment, an effect mitigated by prior inhalation of 5% CO2. Three hours post-injury, TBI results in a significant reduction in general exploratory locomotor activity as compared to sham treatment, an effect that is also mitigated by prior inhalation of 5% CO2. Inhalation of CO2 however was found to have no effect on TBI-elicited increases in cortical tnf-α mRNA expression indicative of a complex biologic mechanism behind observed physiologic effects. Future studies will seek to ascertain molecular adaptations associated with the ability of CO2 to mitigate TBI-induced effects in vivo. These studies provide the first in vivo evidence identifying a targetable biologic mechanism to reduce the effects of primary injury and may lead to viable medical devices and methodologies for the prevention of mild TBI in contact sports and/or military operations.

Increases in noise complaints during the COVID-19 lockdown in Spring 2020: A case study in Greater London, UK

Many cities around the world have claimed that the enforcement of lockdown measures to contain the spread of COVID-19 and the corresponding limitations of human activities led to reduced environmental noise levels. However, noise complaints reported by many local authorities were on the rise soon after the local lockdowns came into force. This research took Greater London in the UK as a case study. The overall aim was examining how noise complaints changed during the first stages of the lockdown implementation, during Spring 2020, both locally and at city scale, and how urban factors may have been influencing them. Noise complaint and urban factor datasets from the Government's publicly available data warehouse were used. The results show that during the COVID-19 lockdown the number of noise complaints increased by 48%, compared with the same period during Spring 2019. In terms of noise sources, complaints about construction (36%) and neighbourhood (50%) noise showed significant increases. Urban factors, including housing and demographic factors, played a more significant role than the actual noise exposure to road and rail traffic noise, as derived from the London noise maps. In detail, the change rate of noise complaints was higher in areas with higher unemployment rates, more residents with no qualifications, and lower house price. It is expected that this study could help government with allocating resources more effectively and achieve a better urban environment.

Measurements of the dermal exposure to bystanders from direct off‐crop drift during the application of plant protection products

AbstractWe determined the dermal exposure of plant protection products containing prothioconazole (PTZ) after spraying a standard crop using a tractor‐operated boom sprayer. Dermal exposure of adult and child bystanders to PTZ and its metabolite, PTZ‐desthio was quantified in bystander drift studies. Exposure was greater on mannequins placed 2 m from the zero line, compared with 5 m or 8 m. When the overall boom height above the ground was the same, the relative boom and canopy heights had no impact on the spray drift, allowing pooling of data from different studies. Wind tunnel experiments were used to compare two flat fan nozzle types, which allowed dermal exposure measured in early bystander field studies using the flat fan TeeJet XR 110 03 nozzle to be adjusted using a conversion factor to reflect exposure from Hypro F110‐03 nozzles. Values from studies using both flat fan nozzle types were pooled and compared with exposure using drift reduction nozzles. For the first time, 3D life‐size mannequins used in field studies have shown that drift reduction nozzles exceed the EFSA‐recommended 50% reduction in drift (potential exposure was reduced by 58–67%). The BREAM2 (Bystander and Resident Exposure Assessment Model) model resulted in better predictions of measured dermal exposure of PTZ equivalents than BREAM, albeit producing more conservative values for the 75th and 95th percentiles of potential dermal exposure compared to field studies (2.6‐fold higher than measured values). Our results using measured potential and actual exposures indicate that the EFSA calculation of 18% protection by light clothing was too conservative.

Occupational Radiation Exposure and Validity of National Dosimetry Registry among Korean Interventional Radiologists.

The national dose registry (NDR) contains essential information to help protect radiation workers from radiation-related health risks and to facilitate epidemiological studies. However, direct validation of the reported doses has not been considered. We investigated the validity of the NDR with a personal dosimeter monitoring conducted among Korean interventional radiologists. Among the 56 interventional radiologists, NDR quarterly doses were compared with actively monitored personal thermoluminescent dosimeter (TLD) doses as standard measures of validation. We conducted analyses with participants categorized according to compliance with TLD badge-wearing policies. A correlation between actively monitored doses and NDR doses was low (Spearman ρ = 0.06), and the mean actively monitored dose was significantly higher than the mean NDR dose (mean difference 0.98 mSv) in all participants. However, interventional radiologists who wore badges irregularly showed a large difference between actively monitored doses and NDR doses (mean difference 2.39 mSv), and participants who wore badges regularly showed no apparent difference between actively monitored doses and NDR doses (mean difference 0.26 mSv). This study indicated that NDR data underestimate the actual occupational radiation exposure, and the validity of these data varies according to compliance with badge-wearing policies. Considerable attention is required to interpret and utilize NDR data based on radiation workers’ compliance with badge-wearing policies.

Modelling the impact of nucleolin expression level on the activity of F3 peptide-targeted pH-sensitive pegylated liposomes containing doxorubicin.

Strategies targeting nucleolin have enabled a significant improvement in intracellular bioavailability of their encapsulated payloads. In this respect, assessment of the impact of target cell heterogeneity and nucleolin homology across species (structurally and functionally) is of major importance. This work also aimed at mathematically modelling the nucleolin expression levels at the cell membrane, binding and internalization of pH-sensitive pegylated liposomes encapsulating doxorubicin and functionalized with the nucleolin-binding F3 peptide (PEGASEMP), and resulting cytotoxicity against cancer cells from mouse, rat, canine, and human origin. Herein, it was shown that nucleolin expression levels were not a limitation on the continuous internalization of F3 peptide-targeted liposomes, despite the saturable nature of the binding mechanism. Modeling enabled the prediction of nucleolin-mediated total doxorubicin exposure provided by the experimental settings of the assessment of PEGASEMP's impact on cell death. The former increased proportionally with nucleolin-binding sites, a measure relevant for patient stratification. This pattern of variation was observed for the resulting cell death in nonsaturating conditions, depending on the cancer cell sensitivity to doxorubicin. This approach differs from standard determination of cytotoxic concentrations, which normally report values of incubation doses rather than the actual intracellular bioactive drug exposure. Importantly, in the context of development of nucleolin-based targeted drug delivery, the structural nucleolin homology (higher than 84%) and functional similarity across species presented herein, emphasized the potential to use toxicological data and other metrics from lower species to infer the dose for a first-in-human trial.

Beebread consumption by honey bees is fast: results of a six-week field study

Due to their foraging behavior, honey bees interact with the landscape. As a result, honey bees and their brood will be exposed to pesticides through nectar and pollen entering the hive. Although these pathways seem rather straightforward, there are several steps between the entry of nectar and pollen and its consumption by the colony. One of the aspects involved here is the time between collection and consumption of pollen in the hive. This is of importance for the actual exposure of nurse bees and larvae to pesticides in pollen. Although lab and short-term field studies indicated that bees prefer to consume freshly stored pollen, this has to our knowledge not been verified in a long-term field study under realistic environmental and apiculturist conditions. To study pollen consumption dynamics, influx and consumption were recorded at 3 or 4 day intervals over a six-week period in two colonies. It was demonstrated that throughout the experimental period, beebread consumption was high in the first 3 to 5 days after collection, over which approximately 70% was consumed. The remaining 30% was consumed within a 2 to 3 week period. Pollen consumption is swift and indicates that only limited time is available for potential degradation processes. As actual data on degradation of pesticides in stored pollen are not available, a justified worse case assumption would be that the actual exposure concentrations consumed by the nurse bees and larvae are the same as the concentrations in collected pollen.

Effect of body mass index on pharmacokinetics of paclitaxel in patients with early breast cancer.

ABSTRACTBackgroundPaclitaxel is dosed according to body surface area (BSA) but there is scant information on actual drug exposure in overweight and obese patients.MethodsEarly breast cancer patients receiving paclitaxel at 175 mg/m2 every 3 weeks, in two BMI groups (normal, 18–24.9 kg/m2 and overweight/obese, ≥25 kg/m2, respectively), matched for age, serum albumin and bilirubin levels using minimization technique, were included. Sparse pharmacokinetic (PK) sampling was performed at 7 time points from 0 h until 24 h of starting paclitaxel in cycle 1. Paclitaxel concentration was measured using a validated LCMS/MS method. Covariate effect on paclitaxel PK was evaluated by population PK analysis using NONMEM software.ResultsEighteen female patients each were enrolled in normal and overweight groups with mean BMI of 21.62 ± 2.06 and 28.16 ± 2.31 kg/m2, mean BSA of 1.44 ± 0.11 and 1.69 ± 0.14 m2 and mean paclitaxel dose of 250 ± 18 and 293 ± 21 mg, respectively. Model predicted AUC and dose normalized AUC (mean ±SD) in the normal BMI versus overweight obese groups were 23 ± 11.0 µmol*h/L versus 25.7 ± 13.7 µmol*h/L (two‐sample t‐test p > 0.05) and 0.08 ± 0.04 (µmol*h/L)/ µmol versus 0.08 ± 0.04 (µmol*h/L)/ µmol (2‐sample t‐test p > 0.05), respectively. No significant correlation was observed between BMI and standardized dose normalized AUC (Pearson's correlation coefficient, −0.009; p > 0.05).ConclusionWhen dosed according to BSA calculated using actual body weight there is no significant difference in paclitaxel exposure between normal and overweight women. Using alternative descriptors of weight to calculate BSA could lead to under‐dosing of this drug.Trial registrationThis study is registered in the Clinical Trials Registry of India CTRI/2015/09/006193.

Method for Estimation of Time at Temperature Histogram of Vehicle Interior Parts Exposed to Meteorological Environments around the World (Third Report)

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;In order to help guarantee the durability and reliability of vehicle interior parts, it is necessary to use time at temperature histogram data for the parts when they are exposed to actual meteorological environments as criteria for judgment. In order to do so, it would be necessary to conduct actual vehicle exposure tests in the regions throughout the world in which the vehicles will be sold, which is unrealistic. The research discussed in this paper proposes a method of estimating the time at temperature histogram for vehicle interior parts when exposure tests are conducted at locations throughout the world using vehicle-specific constants obtained from actual vehicle exposure tests conducted in a single location and publicly available annual meteorological data.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Using the same vehicle, exposure tests were conducted sequentially in three locations: Yomitan Village in Okinawa Prefecture (2016); a Honda parking lot in Haga, Tochigi Prefecture (2017); and a vacant lot belonging to a partner company in Takasu, Hokkaido Prefecture (2018). An analysis performed using hourly temperature measurement data and meteorological data found that air temperature is the basic temperature for the interior parts, and increases in their temperature above the air temperature were proportional to the total solar radiation or the amount of radiant heat from the instrument panel. It was also found that the degree of change in the temperatures of interior parts in relation to the amount of radiant heat, in other words the constants of proportionality, were constants specific to the vehicle used in the exposure test and not dependent on the location of the exposure test, or the season or weather in which it was conducted. It was possible to express the temperatures of the interior parts by means of these vehicle-specific constants and a linear model of the variables of air temperature and total solar radiation. Calculated values accorded well with measured values. Using this model, it has become possible to calculate time at temperature histogram data for vehicle interior parts when exposure tests are conducted at locations throughout the world.&lt;/div&gt;&lt;/div&gt;

What is the actual exposure of organic compounds on Chironomus riparius? - A novel methodology enabling the depth-related analysis in sediment microcosms

A novel active sampling method enabled determination of sediment depth profiles revealing the spatial distribution of model compounds N,N-dimethylsulfamide, fluopyram and bixafen (low, medium, high adsorption affinity) in sediment microcosms according to OECD Test 218/219 (Sediment-Water Chironomid Toxicity Test Using Spiked Sediment/Spiked Water). After the overlying water was removed, plastic tubes were inserted into the sediment and the microcosms were frozen. For depth-related analysis, each “sediment core” was mounted in a cutting device and sawed into three 5-mm-slices, respectively (top, middle, bottom). Each slice was centrifuged for sediment and pore water separation. By various sampling dates within 28 days, we could follow the behavior of model compounds depending on sorption affinities and display specific distribution patterns within the sediment. N,N-dimethylsulfamide showing no sediment adsorption, migrated unhindered in (OECD 219) and out (OECD 218) of the sediment via pore water, resulting in homogenous distributions in both test designs. Fluopyram with moderate adsorption affinity revealed a concentration gradient with declining amounts from top to bottom layer (OECD 219) and higher amounts in the middle and bottom layer as compared to the top layer (OECD 218). Bixafen providing a strong adsorption affinity accumulated in the top layer in OECD 219, while no concentration gradients became visible in OECD 218. For establishing a Toxic Substances in Surface Waters (TOXSWA) model, we compared our measurements with simulated results revealing good agreements. The presented methodology is a useful tool to determine more realistic sediment and pore water concentrations, which the Chironomid larvae are exposed to.

Regional comparison of self-reported late pregnancy cigarette smoking to mass spectrometry analysis.

To report a more accurate prevalence estimate of late pregnancy nicotine exposures. A cross-sectional study during a 2-month period in 2019. Participants were women delivering in any of the six county maternity hospitals who consented to universal drug testing at the time of delivery as part of routine hospital admission. Of 2531 tested samples, 18.7% tested positive for high levels of cotinine indicating primary smoking or other primary use of tobacco products. Together, 33.0% of the study population tested positive for nicotine exposure during late pregnancy compared to vital records which reported 8.2% cigarette smoking during the third trimester of pregnancy and 10.5% cigarette smoking at any time during pregnancy through maternal self-report. Captured vital birth smoking measures vastly underreport actual primary exposures to nicotine products. Vital birth data also fail to capture secondhand exposures which constitute a significant proportion of the population.

Toxicological approaches for the quantitative inhalation risk assessment of toxic metals from tobacco smoke: application on the deterministic and probabilistic inhalation risk assessment of cadmium for Austrian smokers

Objective The objective of this study was the assessment of risks from inhalation exposure of Austrian smokers to cadmium through established toxicological approaches with emphasis on the exposure assessment component, which is challenging regarding the actual amount of metal that is inhaled and the simulation of the smoking pattern. Materials and methods Exposure assessment comprised an estimation of the proportion of cadmium inhaled through smoking and actual occurrence data in tobacco products and survey smoking habits, which were integrated in alternative scenarios through a deterministic and a probabilistic Monte Carlo simulation method. Risks were characterized through the comparison of the exposure with health-based guidance values, as well as through the assessment of the excess lifetime cancer risk (ELCR), the non-cancer hazard quotient (NCHQ), and the margin of exposure (MOE). The strengths, the uncertainties, and the limitations of the different methodologies were discussed. Results and discussion Upper exposures are close or exceed the Permitted Daily Exposure. Respiratory ELCRs are unacceptable compared to the benchmark range of 1.0E–06 to 1.0E–04. Renal and respiratory NCHQs exceed the target value of 1.0 by 3- to 17-fold. MOEs are not protective enough for cancer and non-cancer effects. The amount of cadmium that reaches the lung is a key source of uncertainty. Conclusion Probabilistic estimates provide a refined capture of the actual inhalation exposure. Risk estimates and gender and age profiles are alarming, especially for young smokers. Application of toxicological approaches, combined with realistic assessment of the inhalation exposure levels, can support risk communication and management.

A critical review on human internal exposure of phthalate metabolites and the associated health risks.

Phthalates (PAEs) are popular synthetic chemicals used as plasticizers and solvents for various products, such as polyvinyl chloride or personal care products. Human exposure to PAEs is associated with various diseases, resulting in PAE biomonitoring in humans. Inhalation, dietary ingestion, and dermal absorption are the major human exposure routes. However, estimating the actual exposure dose of PAEs via an external route is difficult. As a result, estimation by internal exposure has become the popular analytical methods to determine the concentrations of phthalate metabolites (mPAEs) in human matrices (such as urine, serum, breast milk, hair, and nails). The various exposure sources and patterns result in different composition profiles of PAEs in biomatrices, which vary from country to country. Nevertheless, the mPAEs of diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP), and di-(2-ethylhexyl) phthalate (DEHP) are predominant in the urine. These mPAEs have greater potential health risks for humans. Children have been observed to exhibit higher exposure risks to several mPAEs than adults. Besides age, other influencing factors for phthalate exposure are gender, jobs, and residential areas. Although many studies have reported biological monitoring of PAEs, only a few reviews that adequately summarized the reports are available. The current review appraised available studies on mPAE quantitation in human biomatrices and estimated the dose and health risks of phthalate exposure. While some countries lack biomonitoring data, some countries' data do not reflect the current PAE exposure. Thence, future studies should involve frequent PAE biomonitoring to accurately estimate human exposure to PAEs, which will contribute to health risk assessments of human exposure to PAEs. Such would aid the formulation of corresponding regulations and restrictions by the government.