In keeping with the fundamental practice of transparency in the discussion and resolution of ethics conflicts raised by research, a summary of ethics issues raised during Portuguese biomonitoring in health surveillance and research is presented and, where applicable, their resolution is described.
Projects underway aim to promote the surveillance of public health related to the presence of solid waste incinerators or to study associations between human exposure to environmental factors and adverse health effects. The methodological approach involves biomonitoring of heavy metals, dioxins and/or other persistent organic pollutants in tissues including blood, human milk and both scalp and pubic hair in groups such as the general population, children, pregnant women or women attempting pregnancy. As such, the projects entail the recruitment of individuals representing different demographic and health conditions, the collection of body tissues and personal data, and the processing of the data and results.
The issue of autonomy is raised during the recruitment of participants and during the collection of samples and data. This right is protected by the requirement for prior written, informed consent from the participant or, in the case of children, from their guardian. Recruitment has been successful, among eligible participants, in spite of incentives rarely being offered. The exception has been in obtaining guardians' consent for children's participation, particularly for blood sampling. In an attempt to mitigate the harm-benefit ratio, current research efforts include alternative less invasive biomarkers.
Surveys are currently being conducted under contract as independent biomonitoring actions and as such, must be explicitly disclosed as a potential conflict of interests. Communication of results to participants is in general only practised when a health issue is present and corrective action possible. Concerning human milk a careful approach is taken, considering breast-feeding's proven benefits.
No national legislation currently accounts for the surveillance component of biomonitoring as distinct from research. Ethics issues arising within the domain of research are resolved according to available regulations. For issues encountered during surveillance, the same principles are used as guidance, completed by the authors' best judgement and relevant ethics committees' findings.
Normative scores for patient-rated outcome (PRO) instruments are important for providing patient-centered, whole-person care and making informed clinical decisions. Although normative values for the Pediatric Quality of Life Generic Core Scale (PedsQL) have been established in the general, healthy adolescent population, whether adolescent athletes demonstrate similar values is unclear.
To compare PedsQL scores between adolescent athletes and general, healthy adolescent individuals.
Patients or Other Participants:
A convenience sample of 2659 interscholastic athletes (males = 2059, females = 600, age = 15.7 ± 1.1 years) represented the athlete group (ATH), and a previously published normative dataset represented the general, healthy adolescent group (GEN).
All participants completed the PedsQL during 1 testing session.
Main Outcome Measure(s):
The PedsQL consists of 2 summary scores (total, psychosocial) and 4 subscale scores (physical, emotional, social, school), with higher scores indicating better health-related quality of life (HRQOL). Groups were stratified by age (14, 15, or 16 years old). Independent-samples t tests were conducted to compare between-groups and sex differences.
The ATH group scored higher than the GEN group across all ages for total and psychosocial summary scores and for emotional and social functioning subscale scores (P ≤ .005). For physical functioning, scores of the 15-year-old ATH were higher than for their GEN counterparts (P = .001). Both 14- and 15-year-old ATH scored higher than their GEN counterparts for the school functioning subscale (P ≤ .013), but differences between 16-year olds were not significant (P = .228). Male adolescent athletes reported higher scores than female adolescent athletes across all scores (P ≤ .001) except for social functioning (P = .229).
Adolescent athletes reported better HRQOL than GEN, particularly in emotional functioning. These findings further support the notion that ATH constitutes a unique population that requires its own set of normative values for self-reported, patient-rated outcome instruments.
patient outcome assessment; patient-centered care; physical activity
Originally isolated on the basis of its capacity to stimulate T-cell maturation and proliferation, avian thymic hormone (ATH) is nevertheless a parvalbumin, one of two β-lineage isoforms expressed in birds. We recently learned that addition of Ca2+-free ATH to a solution of 8-anilinonaphthalene-1-sulfonate (ANS) markedly increases ANS emission. This behavior, not observed in the presence of Ca2+, suggests that apolar surface area buried in the Ca2+-bound state becomes solvent-accessible upon Ca2+ removal. In order to elucidate the conformational alterations that accompany Ca2+ binding, we have obtained the solution structure of the Ca2+-free protein using NMR spectroscopy and compared it to the Ca2+-loaded protein, solved by x-ray crystallography. Although the metal ion-binding (CD-EF) domains are largely coincident in the superimposed structures, a major difference is observed in the AB domains. The tight association of helix B with the E and F helices in the Ca2+-bound state is lost upon removal of Ca2+, producing a deep hydrophobic cavity. The B helix also undergoes substantial rotation, exposing the side-chains of F24, Y26, F29, and F30 to solvent. Presumably, the increase in ANS emission observed in the presence of unliganded ATH reflects the interaction of these hydrophobic residues with the fluorescent probe. The increased solvent exposure of apolar surface area in the Ca2+-free protein is consistent with previously collected scanning calorimetry data, which indicated an unusually low change in heat capacity upon thermal denaturation. The Ca2+-free structure also provides added insight into the magnitude of ligation-linked conformational alteration compatible with a high-affinity metal ion-binding signature. The exposure of substantial apolar surface area suggests the intriguing possibility that ATH could function as a reverse Ca2+ sensor.
calcium-binding protein; EF-hand protein; parvalbumin; NMR structure; crystal structure
Bioethical principles are widely used as a normative framework in areas of human research and medical care. In recent years there has been increasing formalization of their use in public health decisions. The "traditional bioethical principles" are applied in this discussion to the important issue human biomonitoring for environmental exposures. They are: (1) Autonomy – Also known as the "respect for humans" principle, people understand their own best interests; (2) Beneficence – "do good" for people; (3) Nonmaleficence – "do no harm"; (4) Justice – fair distribution of benefits and costs (including risks to health) across stakeholders.
Some of the points made are: (1) There is not a single generic bioethical analysis applicable to the use of human biomonitoring data, each specific use requires a separate deliberation; (2) Using unidentified, population-based biomonitoring information for risk assessment or population surveillance raises fewer bioethical concerns than personally identified biomonitoring information such as employed in health screening; (3) Companies should proactively apply normative bioethical principles when considering the disposition of products and by-products in the environment and humans; (4) There is a need for more engagement by scholars on the bioethical issues raised by the use of biomarkers of exposure; (5) Though our scientific knowledge of biology will continue to increase, there will always be a role for methods or frameworks to resolve substantive disagreements in the meaning of this data that are matters of belief rather than knowledge.
Background: Biomonitoring data reported in the National Report on Human Exposure to Environmental Chemicals [NER; Centers for Disease Control and Prevention (2012)] provide information on the presence and concentrations of > 400 chemicals in human blood and urine. Biomonitoring Equivalents (BEs) and other risk assessment–based values now allow interpretation of these biomonitoring data in a public health risk context.
Objectives: We compared the measured biomarker concentrations in the NER with BEs and similar risk assessment values to provide an across-chemical risk assessment perspective on the measured levels for approximately 130 analytes in the NER.
Methods: We identified available risk assessment–based biomarker screening values, including BEs and Human Biomonitoring-I (HBM-I) values from the German Human Biomonitoring Commission. Geometric mean and 95th percentile population biomarker concentrations from the NER were compared to the available screening values to generate chemical-specific hazard quotients (HQs) or cancer risk estimates.
Conclusions: Most analytes in the NER show HQ values of < 1; however, some (including acrylamide, dioxin-like chemicals, benzene, xylene, several metals, di-2(ethylhexyl)phthalate, and some legacy organochlorine pesticides) approach or exceed HQ values of 1 or cancer risks of > 1 × 10–4 at the geometric mean or 95th percentile, suggesting exposure levels may exceed published human health benchmarks. This analysis provides for the first time a means for examining population biomonitoring data for multiple environmental chemicals in the context of the risk assessments for those chemicals. The results of these comparisons can be used to focus more detailed chemical-specific examination of the data and inform priorities for chemical risk management and research.
biomonitoring; Biomonitoring Equivalents; blood; cancer risk; CDC National Exposure Report; hazard quotient; NHANES; risk assessment; urine
Adult-type hypolactasia (AtH or lactase non-persistence) is the physiological decline in lactase activity that manifests in majority of the world’s population after weaning. Recently, various single-nucleotide polymorphisms (SNPs) upstream of lactase gene (LCT) have been suggested to be associated with AtH or the lactase persistent trait in different human populations. C/T -13910 SNP was found be completely associated with AtH in Finnish population, and G/A -22018 SNP was found to be strongly, but not completely, associated with AtH. The aim of this study was to correlate G/A -22018 SNP with intestinal lactase activity in North Indian children. These children were also genotyped for C/T -13910 SNP. We also examined the differences in milk consumption and milk-related clinical symptoms in children with different genotypes of G/A -22018 and C/T -13910 SNPs. Intestinal biopsies were obtained from 231 children aged 2–16 years undergoing routine endoscopy for various abdominal complaints. The biopsies were assayed for lactase, sucrase, and maltase activities and genotyped for G/A -22018 and C/T -13910 SNPs using restriction fragment length polymorphism and DNA sequencing analysis. There was a significant correlation between lactase activity and different genotypes of G/A -22018 SNP. Children with G/G -22018 genotype had low lactase activity. With a reference value of <10 U/g protein (lactase activity) to be indicative of AtH, the sensitivity and specificity of genetic test based on G/A -22018 SNP was 94.4 and 94.1 %, respectively. Furthermore, the consumption of milk was lower in children with G/G -22018 genotype. Flatulence was the only symptom significantly more frequent among the children with G/G -22018 genotype compared to those with G/A and A/A -22018 genotypes. However, most of the children with G/G -22018 genotype seem to tolerate small amounts of milk without any significant difference in gastrointestinal symptoms from those with G/A and A/A -22018 genotypes.
Adult-type hypolactasia; G/A -22018 SNP; Milk intake; Indian children
The Centers for Disease Control and Prevention provides biomonitoring data in the United States as part of the National Health and Nutrition Examination Survey (NHANES). Recently, Statistics Canada initiated a similar survey — the Canadian Health Measures Survey (CHMS). Comparison of US and Canadian biomonitoring data can generate hypotheses regarding human exposures from environmental media and consumer products. To ensure that such comparisons are scientifically meaningful, it is essential to first evaluate aspects of the surveys' methods that can impact comparability of data. We examined CHMS and NHANES methodologies, using bisphenol A (BPA) as a case study, to evaluate whether survey differences exist that would hinder our ability to compare chemical concentrations between countries. We explored methods associated with participant selection, urine sampling, and analytical methods. BPA intakes were also estimated to address body weight differences between countries. Differences in survey methods were identified but are unlikely to have substantial impacts on inter-survey comparisons of BPA intakes. BPA intakes for both countries are below health-based guidance values set by the US, Canada and the European Food Safety Authority. We recommend that before comparing biomonitoring data between surveys, a thorough review of methodologic aspects that might impact biomonitoring results be conducted.
NHANES; CHMS; bisphenol A; intake; biomonitoring; methodological comparison
The present paper deals with the assessment of heavy metals in soil and roadside dust around Misurata City Centre and industrial areas/roads in the period of October 2011–May 2012. The levels of Pb, Fe, Zn, Ni, Cd, Cr, and Cu in settled dust samples collected near small streets, playgrounds, gas stations and main streets in the Misurata Area have been determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Also, the levels of same heavy metals in industrial areas have been determined. Metal concentration trend variation was also discussed in relation with traffic density and other sources of fugitive emission around different sites on each road/area. The overall mean concentration for main streets was significantly higher (P < 0.05) than for other small streets, where Misurata has been the centre of fierce fighting and is located in a frontline battle zone in the Libyan war; therefore most of metal concentrations in surface soil in the fighting area Tripoli Street and Benghazi Street were higher than those from the other sites (outside fighting area).
The Dublin SURGE (Soil Urban Geochemistry) Project is Dublin’s first baseline survey of heavy metals and persistent organic pollutants in topsoils and is part of a Europe-wide initiative to map urban geochemical baselines in ten cities. 1,058 samples were collected as part of a stratified random sampling programme in the greater Dublin area to give an overview of baseline conditions in the city. Samples were analysed for 31 inorganic elements including heavy metals. Analysis of results indicates that the concentrations of lead, copper, zinc and mercury are strongly influenced by human activities, with elevated concentrations in the city docklands, inner city and heavy industry areas. Sources of heavy metals in these areas may include historical industry, coal burning, re-use of contaminated soil, modern traffic and leaded paint and petrol. Concentrations of other inorganic elements in topsoil show patterns which are strongly related to regional bedrock parent material. The spatial distributions of heavy metals, in particular Pb and As, are explored in detail with respect to regional geology and the influence of historical industry on soil quality. Exploratory data, geostatistical and correlation analyses suggest that the concentrations of heavy metals tend to increase as the intensity of historical industrial activity increases. In particular, drinks production, power generation, oil/gas/coal, metals and textile historical industries appear to be the contamination source for several heavy metals. The data provide a geochemical baseline relevant to the protection of human health, compliance with environmental legislation, land use planning and urban regeneration.
Urban geochemistry; Heavy metals; Soil pollution; Historical industry; Human health
Data on human exposure to chemicals in Africa are scarce. A biomonitoring study was conducted in a representative sample of the population in Kinshasa (Democratic Republic of Congo) to document exposure to polycyclic aromatics hydrocarbons.
1-hydroxypyrene (1-OHP) was measured by HPLC fluorescence in spot urine samples from 220 individuals (50.5% women), aged 6–70 years living in the urban area and from 50 additional subjects from the sub-rural area of Kinshasa. Data were compiled as geometric means and selected percentiles, expressed without (μg/L) or with creatinine adjustment (μg/g cr). Multiple regression analyses were applied to factors (creatinine, grilled meat habits and smoking habits) influencing 1-OHP (stepwise procedure, criteria: probability F to enter ≤ 0.05 and probability F to remove ≥ 0.10).
According to the regression models, creatinine, grilled meat habits and smoking habits contribute to explain 45% of the variation in population’s urinary 1-OHP by the environmental exposure. Overall, living in urban area of Kinshasa was associated with increased levels of 1-OHP in urine as compared to a population living in the sub-rural area [GM: 1.8 μg/L (n = 220) versus 1.4 μg/L (n = 50), p < 0.01] as well as compared to the reference values from databases involving American or German populations.
This study reveals the high pyrene (PAH) exposure of the Kinshasa population. However, more work, with a rigorous design in the exposed population (monitoring of air concentrations and identifying other sources of pyrene –PAH exposure), is needed to establish further documentation.
Biomonitoring; Environmental pollution; Organic compounds; Public health; Polycyclic aromatic hydrocarbons
With its inclusion under Action 3 in the Environment and Health Action Plan 2004–2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.
The impact of industrial heavy metal pollution on Scots pine (Pinus sylvestris L.) and black pine (Pinus nigra Arn.) populations was investigated. Sampled pine stands, which were located in Upper Silesia (southern Poland) in an area strongly polluted by heavy metals, consisted of resistant and sensitive trees. To evaluate the adaptation process, genetic structure and diversity was tested using isozyme analysis. Higher levels of Zn, Pb, Cd and Cu were detected in needles of sensitive trees compared with resistant ones. With respect to morphology, Scots pines were more distinctly impaired than black pines. Although black pines had lower heavy metal concentrations, levels in 1-year-old needles, other than Cu, significantly exceeded “reference plant” values (Markert 1994). In both species, resistant trees demonstrated a lower degree of genetic variation than metal-sensitive trees with respect to some enzyme loci (SHDH A, PGI, PGM, MDH C and DIA). This observation was corroborated in sensitive trees by the smaller number of identified alleles and alleles per locus, absence of private alleles and significant excess of homozygotes in relation to expected Hardy–Weinberg equilibrium values. Assuming that only resistant trees of both species survive under conditions of prolonged soil contamination, the observed genetic structure implies that remaining populations will be depleted of some alleles of unknown adaptive value to future selection pressures. Genetic changes induced by heavy metals suggest an important role for specific enzymes—FEST, SHDH A and B, GOT B and PGI—in the adaptation process. Our results may serve as a basis for selection and propagation of individuals appropriate for re-cultivation of areas chemically degraded by industrial activity.
Genetic variation; Heavy metal; Enzymes; Pinus nigra; Pinus sylvestris; Reference plant
The potential for exposure of employees to polybrominated dibenzofurans (PBDFs) and dibenzo-p-dioxins (PBDDs) during extrusion blending of resins containing decabromodiphenyl ether was established through previous air monitoring (area samples) and biomonitoring studies. The findings presented herein are further biomonitoring results for 42 employees and immunological tests for exposed and referent employees. Among potentially exposed men, 2,3,7,8-TBDF and 2,3,7,8-TBDD concentrations in blood lipid ranged from non-detectable to 112 parts per trillion (ppt) and from non-detectable to 478 ppt respectively. Biomonitoring results correlated well with assignments in the extruder work area when adjusted for process changes and engineering improvements and provided biological half life estimates of between 1.1 and 1.9 years for 2,3,7,8-TBDF and between 2.9 and 10.8 years for 2,3,7,8-TBDD. Results for 16 measures of the immune system were examined in relation to exposure (exposed v referent group) and in relation to the biomonitoring data. Some individual trends in immunological parameters with exposure and covariates such as age and cigarette smoking were found (for example, an increase in complement C4 with increasing concentrations of PBDFs and PBDDs, increased lymphocyte subpopulation counts with cigarette smoking); however, the overall clinical assessment was that the immune system of exposed employees was not adversely impacted at these burdens of PBDFs and PBDDs.
The use of biomonitoring data holds promise for characterizing exposure and informing risk assessment. Biomonitoring data have been used successfully to track population trends, identify susceptible populations, and provide indications of emerging environmental health issues. However, there remain challenges associated with interpreting biomonitoring data for risk assessment. An international biomonitoring workshop was convened in September 2004 to explore the use of biomonitoring data in the context of risk assessment. Six compounds were examined as case studies for this workshop, including polybrominated diphenyl ethers (PBDEs). The PBDE case study was developed to provide an example of a persistent compound for which relatively few data are available for human exposure, biomonitoring, and health outcomes. PBDEs are used in hard plastics, electronics, textiles, and polyurethane foam products. The congener pattern downstream of production facilities often resembles the commercial mixture. However, because these compounds persist in the environment and in biota, the patterns of congeners evolve. PBDEs partition into body lipids, and direct measurement of bromodiphenyl ether congeners in biologic specimens provides a good marker of exposure. Data indicate significant variability (> 100-fold range) in lipid-adjusted levels for PBDEs in the general population. It is hypothesized that both exposure and pharmacokinetics may play a role in observed congener profiles. Significant gaps in our ability to interpret PBDE biomonitoring data to address public health and risk assessment questions include limited knowledge of environmental fate and transport of PBDE congeners, limited population-based data for adults, and lack of data for potentially vulnerable populations such as children.
biomonitoring; exposure assessment; PBDE
Biomonitoring of exposure is a useful tool for assessing environmental exposures. The matrices available for analyses include blood, urine, breast milk, adipose tissue, and saliva, among others. The sampling can be staged to represent the particular time period of concern: preconceptionally from both parents, from a pregnant woman during each of the three trimesters, during and immediately after childbirth, from the mother postnatally, and from the child as it develops to 21 years of age. The appropriate sample for biomonitoring will depend upon matrix availability, the time period of concern for a particular exposure or health effect, and the different classes of environmental chemicals to be monitored. This article describes the matrices available for biomonitoring during the life stages being evaluated in the National Children’s Study; the best biologic matrices for exposure assessment for each individual chemical class, including consideration of alternative matrices; the analytical methods used for analysis, including quality control procedures and less costly alternatives; the costs of analysis; optimal storage conditions; and chemical and matrix stability during long-term storage.
adducts; adipose tissue; bioaccumulative; biomonitoring; blood; breast milk; matrix; metabolite; National Children’s Study; nonpersistent; persistent; toxicant; urine
Biologic monitoring (i.e., biomonitoring) is used to assess human exposures to environmental and workplace chemicals. Urinary biomonitoring data typically are adjusted to a constant creatinine concentration to correct for variable dilutions among spot samples. Traditionally, this approach has been used in population groups without much diversity. The inclusion of multiple demographic groups in studies using biomonitoring for exposure assessment has increased the variability in the urinary creatinine levels in these study populations. Our objectives were to document the normal range of urinary creatinine concentrations among various demographic groups, evaluate the impact that variations in creatinine concentrations can have on classifying exposure status of individuals in epidemiologic studies, and recommend an approach using multiple regression to adjust for variations in creatinine in multivariate analyses. We performed a weighted multivariate analysis of urinary creatinine concentrations in 22,245 participants of the Third National Health and Nutrition Examination Survey (1988–1994) and established reference ranges (10th–90th percentiles) for each demographic and age category. Significant predictors of urinary creatinine concentration included age group, sex, race/ethnicity, body mass index, and fat-free mass. Time of day that urine samples were collected made a small but statistically significant difference in creatinine concentrations. For an individual, the creatinine-adjusted concentration of an analyte should be compared with a “reference” range derived from persons in a similar demographic group (e.g., children with children, adults with adults). For multiple regression analysis of population groups, we recommend that the analyte concentration (unadjusted for creatinine) should be included in the analysis with urinary creatinine added as a separate independent variable. This approach allows the urinary analyte concentration to be appropriately adjusted for urinary creatinine and the statistical significance of other variables in the model to be independent of effects of creatinine concentration.
biomonitoring; creatinine; creatinine adjustment; urine
Cadmium and lead compounds are classified as human carcinogens by several regulatory agencies. Twenty five percent of all cancer-related deaths are attributed to gastrointestinal cancers (GI Ca). We investigated the levels of 2 different heavy metals (Cd and Pb) in the soils of the Lenjanat region, Isfahan province, Central Iran where intensive agriculture is surrounded by different industries like steel and cement-making factories and mining and gastrointestinal cancers are very common in this province.
Materials and methods:
Two hundred topsoil samples (0-20 cm depth) were collected from agricultural and non-agricultural soils of the region and were analyzed for heavy metals. The metal contents were determined by flame atomic absorption spectrometry.
The findings of this study showed that frequency of gastrointestinal cancers in the study area have been increased in the recent years. Results of soil samples in this region showed that the mean concentration of Pb and Cd were more than 16 and 1 mg kg−1, respectively. The total Cd concentration in most of the samples exceeded the suggested Swiss thresholds (0.8 mg kg−1) but the mean value of Pb concentration in soil was less than the threshold of 50 mg kg−1 set by Swiss Federal Office of Environmental, Forest and Landscape. Compared to the threshold values for heavy metals (Cd and Pb) in soils, data showed that the studied fields were contaminated especially by Cd.
High heavy metals content in the soils seems to play an important etiological role in the carcinogenesis. Excessive accumulation of heavy metals in agricultural soils may not only result in soil contamination, but also lead to elevated heavy metal uptake by crops, and thus affect food quality and safety. Thus, analyzing heavy metals content in crops, water and dust could provide us a better insight to solve the problem.
Gastrointestinal cancers; heavy metals; soil pollution
In Vietnam, environmental pollution caused by small-scale domestic smelting of automobile batteries into lead ingot is a growing concern. The village of Nghia Lo is a smelting craft village located roughly 25 km southeast of Hanoi in the Red River Delta. Despite the concern of toxic metal exposure in the village, biomonitoring among susceptible populations, such as children, has not been previously conducted. The aim of this study was to determine the body burden of toxic metals in children residing in a smelting craft village.
Twenty children from Nghia Lo, Vietnam, ages 18 months to four years were selected for capillary whole blood and toenail biomonitoring. Whole blood lead levels (BLLs) were measured using a portable lead analyzer, and toenail levels of arsenic, cadmium, chromium, lead, manganese, and mercury were analyzed with inductively coupled plasma-mass spectrometry.
The findings show that all of the 20 children had detectable BLLs, and every child had levels that exceeded the Centers for Disease Control and Prevention guideline level of 5 μg/dL. Eighty percent of tested subjects had BLLs higher than 10 μg/dL. Five children (25%) had BLLs greater than 45 μg/dL, the level of recommended medical intervention. In addition to blood lead, all of the children had detectable levels of arsenic, cadmium, chromium, lead, manganese, and mercury in toenail samples. Notably, average toenail lead, manganese, and mercury levels were 157 μg/g, 7.41 μg/g, and 2.63 μg/g respectively, well above levels previously reported in children. Significant Spearman’s rank correlations showed that there were relationships between blood and toenail lead levels (r = 0.65, p < 0.05), toenail levels of lead and cadmium (r = 0.66, p < 0.05), and toenail levels of manganese and chromium (r = 0.72, p < 0.001). Linear regression showed that reducing the distance to the nearest active smelter by half was associated with a 116% increase in BLL (p < 0.05).
The results suggest that children in battery recycling and smelting craft villages in Vietnam are co-exposed to toxic metals. There is an urgent need for mitigation to control metal exposure related to domestic smelting.
Human biomonitoring investigations have provided data on a wide array of chemicals in blood and urine and in other tissues and fluids such as hair and human milk. These data have prompted questions such as a) What is the relationship between levels of environmental chemicals in humans and external exposures? b) What is the baseline or “background” level against which individual levels should be compared? and c) How can internal levels be used to draw conclusions about individual and/or population health? An interdisciplinary panel was convened for a 1-day workshop in November 2004 with the charge of focusing on three specific aspects of biomonitoring: characteristics of scientifically robust biomonitoring studies, interpretation of human biomonitoring data for potential risks to human health, and communication of results, uncertainties, and limitations of biomonitoring studies. In this report we describe the recommendations of the panel.
biomonitoring; communication; design; human health; interpretation; specimen archiving
Using modern analytical technology, it is now possible to measure almost
any chemical present in our bodies. The future role of classical exposure
assessment will perhaps be marginalized because biomonitoring programs
can directly measure the concentration of chemicals that are present
in biologic matrices. Although the concentration of chemicals in
the environment will continue to be measured and related to exposure
parameters, the prioritization of the national environmental agenda will
be dictated by biomonitoring. Recent biomonitoring studies have examined
the levels of > 200 chemicals. Biomonitoring data, by themselves, are
not informative in helping consumers understand their individual
health risk. A major challenge facing those who conduct biomonitoring
programs is how to best communicate the information to the public. In
this article, we review benefits and challenges, along with select
results from the Centers for Disease Control and Prevention’s 2005 National Report on Human Exposure to Environmental Chemicals. We recommend that these data be carefully interpreted, with the goal
of establishing baseline exposure information, rather than creating surrogates
for conclusions about human health risk.
biomarker; biomonitoring; exposure assessment; risk assessment
The routine use of biomonitoring (i.e., measurement of environmental chemicals, their metabolites, or specific reaction products in human biological specimens) to assess internal exposure (i.e., body burden) has gained importance in exposure assessment.
Selection and validation of biomarkers of exposure are critical factors in interpreting biomonitoring data. Moreover, the strong relation between quality of the analytical methods used for biomonitoring and quality of the resulting data is well understood. However, the relevance of collecting, storing, processing, and transporting the samples to the laboratory to the overall biomonitoring process has received limited attention, especially for organic chemicals.
We present examples to illustrate potential sources of unintended contamination of the biological specimen during collection or processing procedures. The examples also highlight the importance of ensuring that the biological specimen analyzed both represents the sample collected for biomonitoring purposes and reflects the exposure of interest.
Besides using high-quality analytical methods and good laboratory practices for biomonitoring, evaluation of the collection and handling of biological samples should be emphasized, because these procedures can affect the samples integrity and representativeness. Biomonitoring programs would be strengthened with the inclusion of field blanks.
BPA; contamination; DEHP; extraction efficiency; field blank; phthalates
The use of human samples to assess environmental exposure and uptake of chemicals is more than an analytical exercise and requires consideration of the utility and interpretation of data as well as due consideration of ethical issues. These aspects are inextricably linked.
In 2004 the EC expressed its commitment to the development of a harmonised approach to human biomonitoring (HBM) by including an action in the EU Environment and Health Strategy to develop a Human Biomonitoring Pilot Study. This further underlined the need for interpretation strategies as well as guidance on ethical issues. A workshop held in December 2006 brought together stakeholders from academia, policy makers as well as non-governmental organisations and chemical industry associations to a two day workshop built a mutual understanding of the issues in an open and frank discussion forum. This paper describes the discussion and recommendations from the workshop.
The workshop developed key recommendations for a Pan-European HBM Study:
1. A strategy for the interpretation of human biomonitoring data should be developed.
2. The pilot study should include the development of a strategy to integrate health data and environmental monitoring with human biomonitoring data at national and international levels.
3. Communication strategies should be developed when designing the study and evolve as the study continues.
4. Early communication with stakeholders is essential to achieve maximum efficacy of policy developments and facilitate subsequent monitoring.
5. Member states will have to apply individually for project approval from their National Research Ethics Committees.
6. The study population needs to have sufficient information on the way data will be gathered, interpreted and disseminated and how samples will be stored and used in the future (if biobanking) before they can give informed consent.
7. The participants must be given the option of anonymity. This has an impact on follow-up.
8. The pilot study should develop guidelines and best practice for Ethics for pan European studies.
In conclusion all participants felt there that there has to be stakeholder involvement in any planned pan-European Human Biomonitoring Study and the format of the workshop was appropriate for such dialogue.
Apolipoprotein E-null mice on a DBA/2J genetic background (DBA-apoE) are highly susceptible to atherosclerosis in the aortic root area compared with those on a 129S6 background (129-apoE). To explore atherosclerosis-responsible genetic regions, we performed a quantitative trait locus (QTL) analysis using 172 male and 137 female F2 derived from an intercross between DBA-apoE and 129-apoE mice. A genome-wide scan identified two significant QTL for the size of lesions at the root: one is Ath44 on Chromosome (Chr) 1 at 158 Mb, and the other Ath45 on Chr 2 at 162 Mb. Ath44 co-localizes with but appears to be independent of a previously reported QTL, Ath1, while Ath45 is a novel QTL. DBA alleles of both Ath44 and Ath45 confer atherosclerosis-susceptibility. In addition, a QTL on Chr 14 at 73 Mb was found significant only in males, and 129 allele conferring susceptibility. Further analysis detected female-specific interactions between a second QTL on Chr 1 at 73 Mb and a QTL on Chr 3 at 21 Mb, and between Chr 7 at 84 Mb and Chr 12 at 77 Mb. These loci for the root atherosclerosis were independent of QTLs for plasma total cholesterol and QTLs for triglycerides, but a QTL for HDL (Chr 1 at 126 Mb) overlapped with the Ath44. Notably, haplotype analysis among 129S6, DBA/2J and C57BL/6 genomes and their gene expression data narrowed the candidate regions for Ath44 and Ath45 to less than 5 Mb intervals where multiple genome wide associations with cardiovascular phenotypes have also been reported in humans. SNPs in or near Fmo3, Sele and Selp for Ath44, and Lbp and Pkig for Ath45 were suggested for further investigation as potential candidates underlying the atherosclerosis susceptibility.
Thiamine (vitamin B1) is an essential molecule for all life forms because thiamine diphosphate (ThDP) is an indispensable cofactor for oxidative energy metabolism. The less abundant thiamine monophosphate (ThMP), thiamine triphosphate (ThTP) and adenosine thiamine triphosphate (AThTP), present in many organisms, may have still unidentified physiological functions. Diseases linked to thiamine deficiency (polyneuritis, Wernicke-Korsakoff syndrome) remain frequent among alcohol abusers and other risk populations. This is the first comprehensive study on the distribution of thiamine derivatives in human biopsies, body fluids and cell lines.
Methodology and Principal Findings
Thiamine derivatives were determined by HPLC. In human tissues, the total thiamine content is lower than in other animal species. ThDP is the major thiamine compound and tissue levels decrease at high age. In semen, ThDP content correlates with the concentration of spermatozoa but not with their motility. The proportion of ThTP is higher in humans than in rodents, probably because of a lower 25-kDa ThTPase activity. The expression and activity of this enzyme seems to correlate with the degree of cell differentiation. ThTP was present in nearly all brain and muscle samples and in ∼60% of other tissue samples, in particular fetal tissue and cultured cells. A low ([ThTP]+[ThMP])/([Thiamine]+[ThMP]) ratio was found in cardiovascular tissues of patients with cardiac insufficiency. AThTP was detected only sporadically in adult tissues but was found more consistently in fetal tissues and cell lines.
Conclusions and Significance
The high sensitivity of humans to thiamine deficiency is probably linked to low circulating thiamine concentrations and low ThDP tissue contents. ThTP levels are relatively high in many human tissues, as a result of low expression of the 25-kDa ThTPase. Another novel finding is the presence of ThTP and AThTP in poorly differentiated fast-growing cells, suggesting a hitherto unsuspected link between these compounds and cell division or differentiation.
Genetics plays a large role in atherosclerosis susceptibility in humans and mice. We attempted to confirm previously determined mouse atherosclerosis‐associated loci and use bioinformatics and transcriptomics to create a catalog of candidate atherosclerosis modifier genes at these loci.
Methods and Results
A strain intercross was performed between AKR and DBA/2 mice on the apoE−/− background generating 166 F2 progeny. Using the phenotype log10 of the aortic root lesion area, we identified 3 suggestive atherosclerosis quantitative trait loci (Ath QTLs). When combined with our prior strain intercross, we confirmed 3 significant Ath QTLs on chromosomes 2, 15, and 17, with combined logarithm of odds scores of 5.9, 5.3, and 5.6, respectively, which each met the genome‐wide 5% false discovery rate threshold. We identified all of the protein coding differences between these 2 mouse strains within the Ath QTL intervals. Microarray gene expression profiling was performed on macrophages and endothelial cells from this intercross to identify expression QTLs (eQTLs), the loci that are associated with variation in the expression levels of specific transcripts. Cross tissue eQTLs and macrophage eQTLs that replicated from a prior strain intercross were identified. These bioinformatic and eQTL analyses produced a comprehensive list of candidate genes that may be responsible for the Ath QTLs.
Replication studies for clinical traits as well as gene expression traits are worthwhile in identifying true versus false genetic associations. We have replicated 3 loci on mouse chromosomes 2, 15, and 17 that are associated with atherosclerosis. We have also identified protein coding differences and multiple replicated eQTLs, which may be useful in the identification of atherosclerosis modifier genes.
atherosclerosis; genetics; transcriptomics