Exposure Levels In Children Research Articles

Assessing heavy metal contamination and health risks in playground dust near cement factory: exposure levels in children

Heavy metals pose significant threats to human health, particularly children. This study aimed to assess heavy metal pollution in children's playgrounds using surface dust as an indicator and to ascertain the associated exposure levels and health risks. A total of one hundred twenty dust samples were collected from the surface of playground toys in areas surrounding the cement factory in Bursa, Türkiye, on precipitation-free days. The heavy metal content of the samples was analyzed using ICP-MS. The average total concentration of heavy metals ranged from 2401 to 6832 mg/kg across the sampling sites, with the highest values observed at PG4, PG3, PG2, and PG1, respectively. The most commonly detected heavy metals in the samples included Cr, Mn, Fe, Co, Cu, Zn, Pb, Cd, As, and Ni. Statistical analysis revealed significant positive correlations (p < 0.01) among Cr, Mn, Fe, Co, Cu, Pb, As, and Ni, with Cu and Pb also showing correlation (p < 0.05). PCA analysis identified three principal components explaining 79.905% of the total variance. The Hazard Quotient (HQ) and Hazard Index values for heavy metals were found to be below the safe threshold (HQ < 1). Quantitative techniques such as the geoaccumulation index and enrichment factor are used to determine pollution levels at the sampling sites. Overall, the results indicate that cement factories significantly contribute to heavy metal pollution, with observed values varying based on proximity to the emission source.

Environmental exposure to melamine and its derivatives and kidney outcomes in children

Melamine caused acute nephrotoxicity in a past food adulteration incident, but it is unclear whether and how widespread ambient exposure to melamine and related compounds might affect pediatric kidney health. We assessed cross-sectional associations between childhood exposure to melamine and its derivatives and biomarkers of kidney injury and health and explored potential heterogeneity by sex suggested by sex-dependent differences in renal physiology. We measured melamine and its derivatives ammeline, ammelide, and cyanuric acid (CYA) in spot urine samples collected from 192 children from an urban site (Seattle, WA) and 187 children from a rural site (Yakima, WA) aged 4–8 years in the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) Study. In addition, biomarkers of kidney injury were measured in the same urine samples, including albumin, total protein, KIM-1, NAG, NGAL, and EGF. We utilized linear regressions to examine associations between individual chemical exposures and kidney biomarkers. Interaction terms examined association modification by sex, as well as potential interactions between melamine and CYA. Despite comparable exposures, girls had higher levels of many kidney injury biomarkers compared to boys. A ten-fold higher melamine concentration was associated with a 18% (95% CI: 5.6%, 31%) higher EGF in the full sample, while ten-fold higher melamine was associated with a 76% (14.1%, 173%) higher KIM-1 in boys but not in girls (−10.1% (−40.6%, 36.1%), interaction p = 0.026). Melamine exhibited significant negative interactions with CYA in association with total protein and NAG that appeared to be specific to girls. Our results suggest possible associations between melamine exposure and markers of kidney injury that may be more pronounced in boys. These findings provide novel insights into melamine and related derivative compound health effects at low levels of exposure in children and emphasize the role of sex in mediating the relationship between nephrotoxicant exposure and kidney injury.

Characterization of titanium dioxide nanoparticles in confectionary products and estimation of dietary exposure level among the Chinese population

Titanium dioxide (TiO2) is widely used in the food industry. Recently, European Commission has banned TiO2 as a food additive, raising public concern about its health risk, especially the nanoparticles (NPs) contained therein. This study aimed to reveal the existence of TiO2 NPs in food and further estimate the dietary exposure level among Chinese population by characterizing particle size distribution, determining Ti content and micro-distribution in food products, and calculating food consumption from the China Health and Nutrition Survey (CHNS). The results showed that TiO2 particle size in food additives and chewing gums was 53.5–230.3 nm and 56.8–267.7 nm respectively, where NPs accounted for 34.7% and 55.6% respectively. TiO2 was firstly in situ presented on the surface of confectionary products with hard shells. The content of TiO2 ranged from 3.2 to 3409.3 μg/g product. Besides, the mean dietary intake was 71.31 μg/kgbw/day for TiO2 and 7.75 μg/kgbw/day for TiO2 NPs among Chinese population, affected by people's dietary habits of different regions. Children's exposure levels was the highest due to their love of sweets. More attention should be paid to risk assessment and management of TiO2 NPs for children in China.

Health risk assessment of dermal exposure to Chlorpyrifos among children in agricultural areas in Sakon Nakhon Province, Thailand

Chlorpyrifos is a widely used agricultural insecticide. Chlorpyrifos exposure affects brain development and children’s overall health. The objective of this study was to assess the health risks from skin exposure to chlorpyrifos and to investigate the factors associated with chlorpyrifos exposure among children in agricultural areas. Residual chlorpyrifos samples were collected from the hands and feet of 130 children (aged 1–3) to analyze chlorpyrifos content using high-pressure liquid chromatography with a diode array detector. Chlorpyrifos residues were detected on the skin of 73.1% of the children tested. The health risk assessment of non-cancerous effects showed that children had dermal chlorpyrifos exposure at 1.46 × 10−5 mg/kg-day, and the hazard quotient (HQ) of child dermal chlorpyrifos exposure was 0.03, which is an acceptable level. The frequency of accompanying parents to pesticide-sprayed areas was significantly associated with dermal chlorpyrifos exposure levels in children (ORadjust =1.44, 95%CI =1.02–2.03). However, children in agricultural areas may be subject to additional health risks from exposure to other pesticides through respiration and ingestion. Therefore, they should not be allowed to accompany their parents to agricultural areas, and a program to prevent pesticides from affecting children in these areas should be developed.

Update on human exposure to glyphosate, with a complete review of exposure in children

BackgroundGlyphosate, a commonly used pesticide, has been the topic of much debate. The effects of exposure to glyphosate remains a contentious topic. This paper provides an update to the existing literature regarding levels of glyphosate exposure in occupationally exposed individuals and focuses or reviewing all the available published literature regarding glyphosate exposure levels in children.MethodsA literature review was conducted and any articles reporting quantifiable exposure levels in humans published since January 2019 (the last published review on glyphosate exposure) were reviewed and data extracted and standardized.ResultsA total of five new studies reporting exposure levels in humans were found including 578 subjects. Two of these studies focused on occupationally exposed individuals while three of them focused on glyphosate exposure levels in children. Given the sparse nature of the new data, previously identified studies on exposure to glyphosate in children were included in our analysis of children’s exposure. The lowest average level of glyphosate exposure reported was 0.28 μg/L and the highest average exposure levels reported was 4.04 μg/L.ConclusionThe literature on glyphosate exposure levels, especially in children, remains limited. Without more data collected in a standardized way, parsing out the potential relationship between glyphosate exposure and disease will not be possible.

Living with parents who smoke predicts levels of toxicant exposure in children

The detrimental effect of secondhand smoke (SHS) on health is well known; due to various factors, efforts to prevent SHS cannot completely eliminate the effect of smoking substances, and SHS has not been sufficiently investigated among children. This study aimed to assess children’s smoke exposure with respect to parents smoking patterns using biomarkers. This study used data from the 2016/2017 Korea National Health and Nutrition Examination Survey. Data pertaining to 486 subjects was extracted. Exposure to smoking among non-smoking children was assessed based on urine levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). The urine NNAL concentration was highest among children with smoking parents and SHS exposure at home (3.829 pg/mg, 95% confidence interval [CI: 1.499–8.330), followed by children with smoking parents and no SHS exposure at home (1.297, 95% CI: 1.080–1.536), and children with nonsmoking parents and no SHS exposure at home (0.996 pg/mg, 95% CI: 1.026–1.427). Living with a smoking parent was associated with exposure to carcinogens, and a critical predictor of tobacco-specific nitrosamine. Prohibition of smoking at home is effective at preventing SHS in children. However, it cannot completely prevent passive smoking, which might be attributable to thirdhand smoking and undetected secondhand smoke.

Exposures of children to neonicotinoids in pine wilt disease control areas.

Neonicotinoid insecticides that have been on the market since 1992 have been used globally including in Japan. Because they are sprayed over forests and agricultural areas, inadvertent toxicity in nontarget insects (especially honey bees) and humans is a matter of public concern. However, information on exposure levels and potential health impacts of neonicotinoids in children living around sprayed areas is scarce. Thus, we determined neonicotinoid exposure levels in children living in communities where thiacloprid was used to control pine wilt disease. A total of 46 children (23 males and 23 females) were recruited for the present study, and informed written consent was obtained from their guardians. Urine specimens were collected before, during, and after insecticide spraying events; and atmospheric particulate matter was also collected. Concentrations of thiacloprid and 6 other neonicotinoid compounds were determined in urine samples and in atmospheric particulate matter specimens using liquid chromatography-electrospray ionization-tandem mass spectrometry. In urine specimens, thiacloprid concentrations were <0.13 μg/L and were detectable in approximately 30% of all samples. Concentrations of the other neonicotinoids, N-dm-acetamiprid, thiamethoxam, dinotefuran, and clothianidin, were 18.7, 1.92, 72.3, and 6.02 µg/L, respectively. Estimated daily intakes of these neonicotinoids were then calculated from urinary levels; although the estimated daily intakes of the neonicotinoids were lower than current acceptable daily intake values, the children were found to be exposed to multiple neonicotinoids on a daily basis. Environ Toxicol Chem 2019;38:71-79. © 2018 SETAC.

EXPOSICIÓN A BENCENO EN UNA POBLACIÓN INFANTIL URBANA DEL NORESTE DE MÉXICO

The aim of this study was to assess the benzene exposure levels in children living in Cadereyta Jimenez in Nuevo Leon state, through determination of urinary trans, trans-muconic acid, a biomarker of benzene exposure. Our results shown that 28 % of the population exceeds the biological exposure index (500 µg/g CR). Considering that benzene is related with hematological malignances it is necessary to undertake studies to assess hematological risks in children living in areas with petrochemical activity.

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe

BackgroundExposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels. MethodsPersonal environmental RF-EMF exposure (μW/m2, power flux density) was measured in 529 children (ages 8–18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC). ResultsMedian total personal RF-EMF exposure was 75.5 μW/m2. Downlink was the largest contributor to total exposure (median: 27.2 μW/m2) followed by broadcast (9.9 μW/m2). Exposure from uplink (4.7 μW/m2) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m2) than night (23.0 μW/m2), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m2) or traveling (171.3 μW/m2), and much lower at home (33.0 μW/m2) or in school (35.1 μW/m2). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample. ConclusionThe largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change.

Assessment of radiofrequency electromagnetic field exposure from personal measurements considering the body shadowing effect in Korean children and parents

We aimed to assess the personal radiofrequency electromagnetic field (RF-EMF) exposure levels of children and adults through their activities, with consideration to the body shadowing effect. We recruited 50 child-adult pairs, living in Seoul, Cheonan, and Ulsan, South Korea. RF-EMF measurements were performed between September and December 2016, using a portable exposure meter tailored to capture 14 Korean radiofrequency (RF) bands ranging from 87.5 to 5875MHz. The participants carried the device for 48h and kept a time-activity diary using a smartphone application in flight mode. To enhance accuracy of the exposure assessment, the body shadowing effect was compensated during the statistical analysis with the measured RF-EMF exposure. The compensation was conducted using the hybrid model that represents the decrease of the exposure level due to the body shadowing effect. A generalized linear mixed model was used to compare the RF-EMF exposure levels by subjects and activities. The arithmetic (geometric) means of the total power density were 174.9 (36.6) μW/m2 for all participants, 226.9 (44.6) for fathers, 245.4 (44.8) for mothers, and 116.2 (30.1) for children. By compensating for the body shadowing effect, the total RF-EMF exposure increased marginally, approximately 1.4 times. Each frequency band contribution to total RF-EMF exposure consisted of 76.7%, 2.4%, 9.9%, 5.0%, 3.3%, and 2.6% for downlink, uplink, WiFi, FM Radio, TV, and WiBro bands, respectively. Among the three regions, total RF-EMF exposure was highest in Seoul, and among the activities, it was highest in the metro, followed by foot/bicycle, bus/car, and outside. The contribution of base-station exposure to total RF-EMF exposure was the highest both in parents and children. Total and base-station RF-EMF exposure levels in Korea were higher than those reported in European countries.

Prenatal and Childhood Exposure to Phthalate Diesters and Thyroid Function in a 9-Year Follow-up Birth Cohort Study

Phthalates are widely used in industry, personal care products, and medications. Recent studies have suggested that phthalate exposure alters thyroid hormones. However, longitudinal studies concerning the association between phthalate exposure and thyroid function in children are scant. Therefore, we examined the association between pre- and postnatal phthalate exposure and thyroid function in children born in 2000-2001. We studied 181 mother-child pairs in central Taiwan and followed-up the children from 2000 to 2009 at 2, 5, and 8 years old. We measured serum levels of thyroxine (T4), free T4, triiodothyronine (T3), and thyroid-stimulating hormone in children by using radioimmunoassay. We quantified seven phthalate metabolites, representing the five most commonly used phthalates, in maternal and child urine samples by using liquid chromatography-tandem mass spectrometry. The metabolites were monoethylhexyl phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) derived from di(2-ethylhexyl) phthalate (DEHP), monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), and monobenzyl phthalate (MBzP). We constructed a linear mixed model to examine these associations after adjustments for covariates. The T4 levels were inversely associated with maternal urinary MEHHP (β = -0.028 [95% confidence interval (CI) = -0.051, -0.006]) and MEOHP (β = -0.027 [-0.050, -0.003]), with similar T3 levels being observed in boys, even when the children exposure levels were considered spontaneously. In the girls, the free T4 levels were inversely associated with levels of maternal urinary MEP (β = -0.042), maternal urinary MBzP (β = -0.050), and children's urinary MEHP (β = -0.027). Early life phthalate exposure was associated with decreased thyroid hormone levels in young children.

Blood Lead Levels among Children in Yaoundé Cameroon.

Blood lead levels (BLLs) are a useful indication of a population exposure to lead from environmental sources. No previous published study had reported BLLs in Cameroon. Our objective is to characterize exposure levels in children to inform policymakers of potential lead exposure sources. We tested the BLLs of 147 children aged 12 months to 6 years residing in Yaoundé, Cameroon, and conducted an extensive questionnaire with their parents or guardians to characterize potential exposure sources. The geometric mean BLL among this population was 8.0 μg/dl and arithmetic mean level was 8.7 μg/dl. These levels are more than sixfold higher than the geometric mean BLL reported in the U.S. and more than fivefold higher than those reported in France. In addition, 88% of the children tested had lead levels greater than 5 μg/dl. One limitation of the study is that the selection of the children sampled was not a random survey. The analysis of the responses to the questionnaire failed to uncover any specific exposure patterns. A statistically significant association was noted between the age of the child’s home and the duration of exclusive breastfeeding with BLLs. The study points to a need for greater efforts to control sources of lead exposure in Cameroon.

The Relationship between Prenatal Phthalate Exposure and Childhood Adipokine

The Relationship between Prenatal Phthalate Exposure and Childhood AdipokineAbstract Number:1977 Hui-Ju Wen*, Hsiu-Ying Ku, Chien-Wen Sun, Chien-Jen Wang, Hsiao-Yen Chen, Pen-Hua Su, and Shu-Li Wang Hui-Ju Wen* Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author , Hsiu-Ying Ku Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author , Chien-Wen Sun Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author , Chien-Jen Wang Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author , Hsiao-Yen Chen Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author , Pen-Hua Su School of Medicine, Chung Shan Medical University, Taiwan, E-mail Address: [email protected] Search for more papers by this author , and Shu-Li Wang Division of Environmental Health & Occupational Medicine, National Health Research Institutes, Taiwan, E-mail Address: [email protected] Search for more papers by this author AbstractIn Taiwan, the prevalence of obesity in children is increased 1.5 folds in the last decade. Exposure to endocrine disruptor, such as phthalates, could affect endocrine system and adipokine secretion. We aimed to investigate the association between prenatal phthalate exposure and childhood adipokine levels using a birth cohort study established in central Taiwan, 2001. A total of 430 pregnant women were originally recruited. Their children had been followed at the age of 2, 5, 8, and 11 years old. Urine and blood samples were collected in the third trimester of pregnancy women and children. Maternal urinary phthalate metabolite concentrations adjusted by urinary creatinine levels were considered as prenatal phthalate ester exposure levels in children. Plasma levels of leptin and adiponectin were evaluated in each follow-up for children’s adipokine markers. We used linear regression analysis and generalized estimating equation (GEE) model to evaluate the relationship between prenatal phthalate exposure and adipokine levels in children. After excluding multiple births and children lost to follow up, a total of 245 pairs with children followed at least once during study period were included in subsequent analysis. An association was found between urinary phthalate metabolite concentrations and weight gain in pregnant women. By GEE model, maternal urinary 5oxoMEHP concentration was found positively associated with children’s body mass index (BMI) values, and negatively associated with adiponectin levels in children. A negative association was also found between MnBP and 5OHMEHP concentration and leptin levels. Prenatal phthalate exposure was found associated with weight gain in pregnant women and BMI, adiponectin, and leptin levels in children. Among them, the effect of DEHP metabolites, including 5oxoMEHP and 5OHMEHP, were more obvious than others. The results suggested that phthalate exposure was related to adipokine levels.

Trends in Diet and Exposure to Chemicals in Dutch Children

Aim: This report presents an overview of trends in dietary patterns and exposure to selected chemicals in children aged 0.5-12 years living in the Netherlands, with the aim to get insight in possible trends in exposure over the last two decades. The compounds included are acrylamide, dioxins, nitrate, organophosphate insecticides, sulphite, sweeteners and some mycotoxins. Approach: Data from literature and the three Dutch National Food Consumption Surveys (DNFCS-1 (1987/1988), DNFCS-2 (1992) and DNFCS-3 (1997/1998)) were analysed. The reported consumption of very young children (aged 8-18months) was described based on two studies conducted in 2000/2001 and 2002. Due to the relatively short time period between these two latter studies, it was not feasible to report of a time trend for very small children. Results: For most of the chemicals a decrease in (mean/median) exposure levels is Grey Literature European Journal of Nutrition & Food Safety, 4(1): 6-7, 2014 7 predicted relative to the most recent exposure assessments reported in the literature. For sweeteners, an increase is more likely, due to an increasing trend in the consumption of light soda’s. For some compounds, (T2/HT2 and sulphite) no conclusions could be drawn. The results are shortly discussed in relation to differences in food consumption survey methods used over time and developments of methodologies used to assess exposure levels. Also the quality of the residue data used in the exposure assessment is addressed. Conclusion: Trends in themselves provide only information on whether exposure levels are likely to increase or decrease in time. Also actual levels of exposure should be addressed and compared to the relevant toxicological reference levels. The comparison of the highest, most recent estimated exposure reported in the literature with a relevant reference dose per chemical demonstrated that for some compounds (acrylamide, DON and dioxins) the reference value was exceeded and that it remains to be seen whether a decreasing trend will result in acceptable exposure levels in children in time. The complete report can be downloaded for free from http://edepot.wur.nl/7507. Full report is also available as ‘Supplementary File’.

Mercury exposure levels in children with dental amalgam fillings.

ABSTRACT%Objectives: Mercury combined with other metals to form solid amalgams has long been used in reconstructive dentistry but its use has been controversial since at least the middle of the 19th century. The exposure and body burden of mercury reviews have consistently stated that there is a deficiency of adequate epidemiological studies addressing this issue. Fish and dental amalgam are two major sources of human exposure to organic (MeHg) and inorganic Hg respectively.Materials and methods: A total of 150 subjects aged between 9 and 14 years were divided into two groups of 75 subjects each depending on their diet, i.e. seafood or nonseafood consuming. Each category was subdivided into three groups based on number of restorations. Scalp hair and urine samples were collected at baseline and 3 months later to assess the organic and inorganic levels of mercury respectively by atomic absorption spectrophotometer (AAS).Results: The mean values of urinary mercury (inorganic mercury) in the group of children with restorations were 1.5915 μg/l as compared to 0.0130 μg/l in the groups with no amalgam restorations (p < 0.001) (Wilcoxon sign rank test and paired t-test). The hair mercury levels (organic mercury) varied signi-ficantly between the fsh-eating group and nonfsh-eating group, the average values being 1.03 μg/l and 0.84 μg/l respectively (p < 0.001) (Mann-Whitney U-test and paired t-test).Conclusion and significance: The notion about the mercury being released from the amalgam restorations as a sole exposure source needs to be put to a rest, as environmental factors collectively overpower the exposure levels from restorations alone.How to cite this article: Varkey IM, Shetty R, Hegde A. Mercury Exposure Levels in Children with Dental Amalgam Fillings. Int J Clin Pediatr Dent 2014;7(3):180-185.

Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT

To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4years, range: 1-9years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30% lower dose and 40% ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30% dose reduction in paediatric chest and abdominal CT, without impairment of image quality. • Iterative reconstruction helps lower radiation exposure levels in children undergoing CT. • Adaptive statistical iterative reconstruction (ASIR) significantly increases SNR without impairing spatial resolution. • For abdomen and chest CT, ASIR allows at least a 30% dose reduction.

Probabilistic mercury multimedia exposure assessment in small children and risk assessment

ObjectivesEmissions of mercury in the environment have been decreasing for several years. However, mercury species are still found in different media (food, water, air and breast-milk). Due to mercury toxicity and typical behaviour in children, we have conducted a mercury exposure assessment in French babies, and small children aged 0 to 36months. MethodConsumption and mercury concentration data were chosen for the exposure assessment. The Monte Carlo technique has been used to calculate the weekly exposure dose in order to integrate inter-individual variability and parameter uncertainty. Exposure values have been compared to toxicological reference values for health risk assessment. ResultsInorganic mercury median exposure levels ranged from 0.160 to 1.649μg/kg of body weight per week (95th percentile (P95): 0.298–2.027µg/kg bw/week); elemental mercury median exposure level in children was 0.11ng/kg bw/week (P95: 28ng/kg bw/week); and methylmercury median exposure level ranged from 0.247 to 0.273µg/kg bw/week (P95: 0.425–0.463µg/kg bw/week). Only elemental mercury by inhalation route (indoor air) and methylmercury by ingestion (fish and breast-milk) seem to lead to a health risk in small children. ConclusionsThese results confirm the importance of assessing total mercury concentration in media like breast-milk, indoor air and dust and methylmercury level in food, other than fish and seafood. In this way, informed monitoring plan and risk assessment in an at-risk sub-population can be set.

DDT, DDE, and 1-hydroxypyrene levels in children (in blood and urine samples) from Chiapas and Oaxaca, Mexico

The aim of this study was to evaluate the DDT, DDE, and 1-hydroxypyrene exposure levels of children living in communities located in southeastern Mexico. The study communities were Lacanja and Victoria in Chiapas state and Ventanilla in Oaxaca state. Children living in Lacanja had total blood DDT levels (mean ± SD, 29,039.6 ± 11,261.4 ng/g lipid) that were significantly higher than those of children in Victoria (10,220.5 ± 7,893.1 ng/g lipid) and Ventanilla (11,659.7 ± 6,683.7 ng/g lipid). With respect to the 1-hydroxypyrene levels in urine samples, the levels in Lacanja (4.8 ± 4.1 μg/L or 4.5 ± 3.9 μmol/mol creatinine) and Victoria (4.6 ± 3.8 μg/L or 3.9 ± 3.0 μmol/mol Cr) were significantly higher than levels found in Ventanilla (3.6 ± 1.4 μg/L or 2.5 ± 0.5 μmol/mol Cr). In conclusion, our data indicate high levels of exposure in children living in the communities studied in this work. The evidence found in this study could be further used as a trigger to revisit local policies on environmental exposures.

Validation of diffusive mini-samplers for aldehyde and VOC and its feasibility for measuring the exposure levels of elementary school children

Exposure to various chemicals can cause adverse effects to health, such as asthma and allergies, especially in children. Data on personal exposure levels in children are scarce, thus small lightweight diffusive mini-samplers for aldehydes and volatile organic compounds (VOCs) were designed to measure the exposure level of children to these chemicals. The aim of the study was to validate and examine the applicability of these mini-samplers for measuring daily chemical exposure. The diffusive mini-samplers are 20 mm in length, 11 mm in diameter, and 1.67 g in weight. The devices are cylindrically shaped with polytetrafluoroethylene membrane filters placed at each end. To measure aldehydes and acetone, 20 mg of 2,4-dinitrophenylhydrazine was used as an absorbent. To measure VOCs, a carbon molecular sieve was used. The sampling rate for each chemical was determined by parallel sampling with active samplers in a closed exposure bag. The blank levels of the chemicals and the storage stability of the device were tested. The mini-samplers were compared to commercially available diffusive samplers. To examine the applicability of the samplers, 65 elementary school children carried them for 24 h. The sampling rates for formaldehyde, acetaldehyde, and acetone were 20.9, 22.9, and 19.7 mL min(-1), respectively. The limits of quantification (LOQ) for the 24-hour sampling by high-performance liquid chromatography/ultraviolet (HPLC/UV) analysis were 8.3, 7.6, and 8.8 μg m(-3) for formaldehyde, acetaldehyde, and acetone, respectively. The sampling rates for the 11 VOCs were determined and ranged from 3.3 mL min(-1) for styrene and 2-ethyl-1-hexanol to 11.7 mL min(-1) for benzene. The LOQ for the 24-hour sampling by gas chromatography-mass spectrometry (GC-MS) analysis ranged from 5.9-105.2 μg m(-3), 1.1-24.7 parts per billion. The storage stability after 5 days ranged from 94.8 to 118.2%. Formaldehyde, acetone, benzene, and toluene were detected above the LOQ in more than 90% of the children, and the median concentrations were 21.7, 20.9, 10.1, and 21.5 μg m(-3), respectively. This study shows that the diffusive samplers developed were suitable for children to carry and were capable of measuring the children's daily chemical exposure.

Objektive Bestimmung der 24-Stunden-Gesamtlärmbelastung: eine Querschnittsstudie in Bayern

Noise can affect well-being and performance of individuals and might be associated with an increased risk of cardiovascular events. To date most epidemiological studies considered exposure from a single source of noise. The EU Environmental Noise Directive (2002/49/EC) requires a summative measurement of ambient noise. This study aimed to capture the participants' exposure to environmental noise by means of personal noise dosimetry. Children (n=628, participation=61%, age 8-12 years), adolescents (n=632, participation=58%, age 13-17 years) and adults (n=482, participation=40%, age 18-65 years) were selected randomly from the population registry of 4 Bavarian towns and were invited to participate in a 24-h measurement using noise dosimetry. Noise exposures during day and night were analyzed separately. In addition, predictors of noise exposure were assessed. For daytime noise exposure mean±standard deviation were in children 80.0±5.8 dB(A), in adolescents 76.0±6.2 dB(A), in adults 72.1±6.1 dB(A) (p(ANOVA)<0.001). During the day personal noise exposure was statistically significantly higher for participants from smaller towns than for those living in Munich, while nighttime noise exposure was highest for participants from Munich [44.1±7.2 dB(A)]. The summative noise exposure in urban Bavaria is high, in particular among children at daytime. Increased exposure levels in children might be caused by themselves while, e.g., playing. Whether the higher daytime exposure in towns is due to high noise levels commuting between home and work has to be assessed in future studies.