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Varshavsky JR, Rayasam SDG, Sass JB, Axelrad DA, Cranor CF, Hattis D, Hauser R, Koman PD, Marquez EC, Morello-Frosch R, Oksas C, Patton S, Robinson JF, Sathyanarayana S, Shepard PM, Woodruff TJ. Current practice and recommendations for advancing how human variability and susceptibility are considered in chemical risk assessment. Environ Health 2023; 21:133. [PMID: 36635753 PMCID: PMC9835253 DOI: 10.1186/s12940-022-00940-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A key element of risk assessment is accounting for the full range of variability in response to environmental exposures. Default dose-response methods typically assume a 10-fold difference in response to chemical exposures between average (healthy) and susceptible humans, despite evidence of wider variability. Experts and authoritative bodies support using advanced techniques to better account for human variability due to factors such as in utero or early life exposure and exposure to multiple environmental, social, and economic stressors.This review describes: 1) sources of human variability and susceptibility in dose-response assessment, 2) existing US frameworks for addressing response variability in risk assessment; 3) key scientific inadequacies necessitating updated methods; 4) improved approaches and opportunities for better use of science; and 5) specific and quantitative recommendations to address evidence and policy needs.Current default adjustment factors do not sufficiently capture human variability in dose-response and thus are inadequate to protect the entire population. Susceptible groups are not appropriately protected under current regulatory guidelines. Emerging tools and data sources that better account for human variability and susceptibility include probabilistic methods, genetically diverse in vivo and in vitro models, and the use of human data to capture underlying risk and/or assess combined effects from chemical and non-chemical stressors.We recommend using updated methods and data to improve consideration of human variability and susceptibility in risk assessment, including the use of increased default human variability factors and separate adjustment factors for capturing age/life stage of development and exposure to multiple chemical and non-chemical stressors. Updated methods would result in greater transparency and protection for susceptible groups, including children, infants, people who are pregnant or nursing, people with disabilities, and those burdened by additional environmental exposures and/or social factors such as poverty and racism.
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Affiliation(s)
- Julia R Varshavsky
- Department of Health Sciences and Department of Civil and Environmental Engineering Northeastern University, Boston, MA, 02115, USA.
| | - Swati D G Rayasam
- Department of Obstetrics, Program on Reproductive Health and the Environment, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
| | | | | | - Carl F Cranor
- Department of Philosophy, University of California, Riverside, Riverside, CA, USA
- Environmental Toxicology Graduate Program, College of Natural and Agricultural Sciences, University of California, Riverside, Riverside, CA, USA
| | - Dale Hattis
- The George Perkins Marsh Institute, Clark University, Worcester, MA, USA
| | - Russ Hauser
- Department of Environmental Health, T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Patricia D Koman
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | | | - Rachel Morello-Frosch
- School of Public Health, University of California, Berkeley, Berkeley, CA, USA
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Catherine Oksas
- University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | | | - Joshua F Robinson
- Department of Obstetrics, Program on Reproductive Health and the Environment, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Sheela Sathyanarayana
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Seattle Children's Research Institute, Seattle, WA, USA
| | | | - Tracey J Woodruff
- Department of Obstetrics, Program on Reproductive Health and the Environment, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
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Kunwittaya S, Ruksee N, Khamnong T, Jiawiwatkul A, Kleebpung N, Chumchua V, Plitponkarnpim A, Nopparat C, Permpoonputtana K. Inorganic arsenic contamination and the health of children living near an inactive mining site: northern Thailand. EXCLI JOURNAL 2022; 21:1007-1014. [PMID: 36110556 PMCID: PMC9441675 DOI: 10.17179/excli2022-4922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/20/2022] [Indexed: 11/10/2022]
Abstract
Arsenic toxicity is a global health problem affecting millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water, and may also be caused by mining and other industrial processes. Acute arsenic poisoning is associated with nausea, vomiting, abdominal pain, and severe diarrhea. Chronic arsenic toxicity results in multisystemic diseases leading to central nervous system (CNS) impairments such as cognitive or intellectual deficits in children. Over the past ten years, arsenic contamination has been reported in northern Thailand. The Ministry of Public Health; Thailand, Forensic Science Institute Thammasat University, and the Research Center to Promote Safety and Prevent Injuries in Children at the Ramathibodi Hospital compiled a report on the health impact of the population within a 10 kilometer radius around a mine tailing in the Phichit, Phitsanulok, and Phetchabun Provinces of Thailand. It showed that more than 30 % of children (aged 8-13 years) had higher than normal arsenic contamination levels based on the Agency for Toxic Substances and Disease Registry (ATSDR). After the publication of that report, the mine was temporarily closed in 2016. Based on this data, this research aimed to follow arsenic contamination after the mining operation had stopped operation for three years. The study showed that 4.5 % of school aged children had levels of inorganic arsenic in their urine, higher than the normal range (ATSDR), showing clearly that inorganic arsenic contamination is still above the normal range in children living near an inactive mining site. Therefore, monitoring heavy metal contamination in Thailand and the health effects on vulnerable children who live near mines during regular operation or after being temporarily suspended can prevent and mitigate possible health impacts.
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Affiliation(s)
- Sarun Kunwittaya
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Nootchanart Ruksee
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Thirata Khamnong
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Athiwat Jiawiwatkul
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Nonthasruang Kleebpung
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Vasunun Chumchua
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Adisak Plitponkarnpim
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand,Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Chutikorn Nopparat
- Innovative Learning Center, Srinakharinwirot University, Sukhumvit 23, Bangkok, 10110, Thailand
| | - Kannika Permpoonputtana
- National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand,*To whom correspondence should be addressed: Kannika Permpoonputtana, National Institute for Child and Family Development, Mahidol University, Nakhon Pathom 73170, Thailand; Phone: (662) 441-0602, Fax: (662) 441-0167, E-mail:
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Emoto C, Johnson TN. Cytochrome P450 enzymes in the pediatric population: Connecting knowledge on P450 expression with pediatric pharmacokinetics. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 95:365-391. [PMID: 35953161 DOI: 10.1016/bs.apha.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cytochrome P450 enzymes play an important role in the pharmacokinetics, efficacy, and toxicity of drugs. Age-dependent changes in P450 enzyme expression have been studied based on several detection systems, as well as by deconvolution of in vivo pharmacokinetic data observed in pediatric populations. The age-dependent changes in P450 enzyme expression can be important determinants of drug disposition in childhood, in addition to the changes in body size and the other physiological parameters, and effects of pharmacogenetics and disease on organ functions. As a tool incorporating drug-specific and body-specific factors, physiologically-based pharmacokinetic (PBPK) models have become increasingly used to characterize and explore mechanistic insights into drug disposition. Thus, PBPK models can be a bridge between findings from basic science and utilization in predictive science. Pediatric PBPK models incorporate additional system specific information on developmental physiology and ontogeny and have been used to predict pharmacokinetic parameters from preterm neonates onwards. These models have been advocated by regulatory authorities in order to support pediatric clinical trials. The purpose of this chapter is to highlight accumulated knowledge and findings from basic research focusing on P450 enzymes, as well as the current status and future challenges of expanding the utilization of pediatric PBPK modeling.
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Affiliation(s)
- Chie Emoto
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Tokyo, Japan; Translational Research Division, Chugai Pharmaceutical Co., Ltd., Tokyo, Japan.
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Mallick P, Moreau M, Song G, Efremenko AY, Pendse SN, Creek MR, Osimitz TG, Hines RN, Hinderliter P, Clewell HJ, Lake BG, Yoon M. Development and Application of a Life-Stage Physiologically Based Pharmacokinetic (PBPK) Model to the Assessment of Internal Dose of Pyrethroids in Humans. Toxicol Sci 2021; 173:86-99. [PMID: 31593217 PMCID: PMC6944222 DOI: 10.1093/toxsci/kfz211] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
To address concerns around age-related sensitivity to pyrethroids, a life-stage physiologically based pharmacokinetic (PBPK) model, supported by in vitro to in vivo extrapolation (IVIVE) was developed. The model was used to predict age-dependent changes in target tissue exposure of 8 pyrethroids; deltamethrin (DLM), cis-permethrin (CPM), trans-permethrin, esfenvalerate, cyphenothrin, cyhalothrin, cyfluthrin, and bifenthrin. A single model structure was used based on previous work in the rat. Intrinsic clearance (CLint) of each individual cytochrome P450 or carboxylesterase (CES) enzyme that are active for a given pyrethroid were measured in vitro, then biologically scaled to obtain in vivo age-specific total hepatic CLint. These IVIVE results indicate that, except for bifenthrin, CES enzymes are largely responsible for human hepatic metabolism (>50% contribution). Given the high efficiency and rapid maturation of CESs, clearance of the pyrethroids is very efficient across ages, leading to a blood flow-limited metabolism. Together with age-specific physiological parameters, in particular liver blood flow, the efficient metabolic clearance of pyrethroids across ages results in comparable to or even lower internal exposure in the target tissue (brain) in children than that in adults in response to the same level of exposure to a given pyrethroid (Cmax ratio in brain between 1- and 25-year old = 0.69, 0.93, and 0.94 for DLM, bifenthrin, and CPM, respectively). Our study demonstrated that a life-stage PBPK modeling approach, coupled with IVIVE, provides a robust framework for evaluating age-related differences in pharmacokinetics and internal target tissue exposure in humans for the pyrethroid class of chemicals.
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Affiliation(s)
| | - Marjory Moreau
- ScitoVation, LLC, Research Triangle Park, North Carolina 27709
| | - Gina Song
- ScitoVation, LLC, Research Triangle Park, North Carolina 27709.,ToxStrategies, Cary, North Carolina 27511
| | | | - Salil N Pendse
- ScitoVation, LLC, Research Triangle Park, North Carolina 27709
| | - Moire R Creek
- Moire Creek Toxicology Consulting Services, Lincoln, California 95648
| | | | - Ronald N Hines
- US EPA, ORD, NHEERL, Research Triangle Park, North Carolina 27709
| | | | | | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK
| | - Miyoung Yoon
- ScitoVation, LLC, Research Triangle Park, North Carolina 27709.,ToxStrategies, Cary, North Carolina 27511
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Parris P, Martin EA, Stanard B, Glowienke S, Dolan DG, Li K, Binazon O, Giddings A, Whelan G, Masuda-Herrera M, Bercu J, Broschard T, Bruen U, Callis CM, Stults CL, Erexson GL, Cruz MT, Nagao LM. Considerations when deriving compound-specific limits for extractables and leachables from pharmaceutical products: Four case studies. Regul Toxicol Pharmacol 2020; 118:104802. [DOI: 10.1016/j.yrtph.2020.104802] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 09/26/2020] [Accepted: 10/06/2020] [Indexed: 12/24/2022]
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Children's Environmental Health: A Systems Approach for Anticipating Impacts from Chemicals. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17228337. [PMID: 33187264 PMCID: PMC7696947 DOI: 10.3390/ijerph17228337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/28/2020] [Accepted: 11/03/2020] [Indexed: 12/14/2022]
Abstract
Increasing numbers of chemicals are on the market and present in consumer products. Emerging evidence on the relationship between environmental contributions and prevalent diseases suggests associations between early-life exposure to manufactured chemicals and a wide range of children’s health outcomes. Using current assessment methodologies, public health and chemical management decisionmakers face challenges in evaluating and anticipating the potential impacts of exposure to chemicals on children’s health in the broader context of their physical (built and natural) and social environments. Here, we consider a systems approach to address the complexity of children’s environmental health and the role of exposure to chemicals during early life, in the context of nonchemical stressors, on health outcomes. By advancing the tools for integrating this more complex information, the scope of considerations that support chemical management decisions can be extended to include holistic impacts on children’s health.
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Sayre RR, Wambaugh JF, Grulke CM. Database of pharmacokinetic time-series data and parameters for 144 environmental chemicals. Sci Data 2020; 7:122. [PMID: 32313097 PMCID: PMC7170868 DOI: 10.1038/s41597-020-0455-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 03/12/2020] [Indexed: 12/20/2022] Open
Abstract
Time courses of compound concentrations in plasma are used in chemical safety analysis to evaluate the relationship between external administered doses and internal tissue exposures. This type of experimental data is rarely available for the thousands of non-pharmaceutical chemicals to which people may potentially be unknowingly exposed but is necessary to properly assess the risk of such exposures. In vitro assays and in silico models are often used to craft an understanding of a chemical's pharmacokinetics; however, the certainty of the quantitative application of these estimates for chemical safety evaluations cannot be determined without in vivo data for external validation. To address this need, we present a public database of chemical time-series concentration data from 567 studies in humans or test animals for 144 environmentally-relevant chemicals and their metabolites (187 analytes total). All major administration routes are incorporated, with concentrations measured in blood/plasma, tissues, and excreta. We also include calculated pharmacokinetic parameters for some studies, and a bibliography of additional source documents to support future extraction of time-series. In addition to pharmacokinetic model calibration and validation, these data may be used for analyses of differential chemical distribution across chemicals, species, doses, or routes, and for meta-analyses on pharmacokinetic studies.
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Affiliation(s)
- Risa R Sayre
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA.
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - John F Wambaugh
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Christopher M Grulke
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27709, USA
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Ohtsu M, Mise N, Ikegami A, Mizuno A, Kobayashi Y, Nakagi Y, Nohara K, Yoshida T, Kayama F. Oral exposure to lead for Japanese children and pregnant women, estimated using duplicate food portions and house dust analyses. Environ Health Prev Med 2019; 24:72. [PMID: 31805868 PMCID: PMC6896297 DOI: 10.1186/s12199-019-0818-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lead is a toxic metal abundant in the environment. Consumption of food contaminated at low levels of lead, especially by small children and pregnant women, raises a health concern. METHODS Duplicated food portions and drinking water were collected over 3 days from 88 children and 87 pregnant women in Shimotsuke, Tochigi, Japan. Participants were recruited in this study between January 2014 and October 2015. Dust was also collected from their homes. Lead concentrations were measured and consequent oral lead exposure levels were estimated for this population at high risk to environmental toxicants. Lead concentrations of peripheral and cord blood, taken from children and pregnant women, and were also analyzed. RESULTS Lead concentrations in food, drinking water, and house dust were low in general. Oral lead exposure to lead was higher for children (Mean ± SEM; 5.21 ± 0.30 μg/kg BW/week) than in pregnant women (1.47 ± 0.13 μg/kg BW/week). Food and house dust were main sources of lead contamination, but the contribution of house dust widely varied. Means ± SEM of peripheral and cord blood lead concentrations were 0.69 ± 0.04 μg/dL and 0.54 ± 0.05 μg/dL, respectively for pregnant women and 1.30 ± 0.07 μg/dL (peripheral only) in children. We detect no correlation between smoking situations and blood lead concentration in pregnant women. CONCLUSION We conclude that oral lead exposure levels for Japanese children and pregnant women were generally low, with higher concentrations and exposure for children than for pregnant women. More efforts are necessary to clarify the sources of lead contamination and reduce lead exposure of the population at high risk even in Japan.
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Affiliation(s)
- Mayumi Ohtsu
- Department of Environmental and Preventive Medicine, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Nathan Mise
- Department of Environmental and Preventive Medicine, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
| | - Akihiko Ikegami
- Department of Environmental and Preventive Medicine, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Atsuko Mizuno
- Department of Pharmacology, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Yayoi Kobayashi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Yoshihiko Nakagi
- Department of Health Science, Asahikawa Medical University, Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8802, Japan
| | - Keiko Nohara
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Takahiko Yoshida
- Department of Health Science, Asahikawa Medical University, Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8802, Japan
| | - Fujio Kayama
- Department of Environmental and Preventive Medicine, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
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De Santis B, Debegnach F, Miano B, Moretti G, Sonego E, Chiaretti A, Buonsenso D, Brera C. Determination of Deoxynivalenol Biomarkers in Italian Urine Samples. Toxins (Basel) 2019; 11:E441. [PMID: 31349679 PMCID: PMC6722612 DOI: 10.3390/toxins11080441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 02/04/2023] Open
Abstract
Deoxynivalenol (DON) is a mycotoxin mainly produced by Fusariumgraminearum that can contaminate cereals and cereal-based foodstuff. Urinary DON levels can be used as biomarker for exposure assessment purposes. This study assessed urinary DON concentrations in Italian volunteers recruited by age group, namely children, adolescents, adults, and the elderly. In addition, vulnerable groups, namely vegetarians and pregnant women, were included in the study. To determine the urinary DON, its glucuronide and de-epoxydated (DOM-1) forms, an indirect analytical approach was used, measuring free DON and total DON (as sum of free and glucuronides forms), before and after enzymatic treatment, respectively. Morning urine samples were collected on two consecutive days, from six different population groups, namely children, adolescent, adults, elderly, vegetarians and pregnant women. Total DON was measured in the 76% of the collected samples with the maximum incidences in children and adolescent age group. Urine samples from children and adolescent also showed the highest total DON levels, up to 17.0 ng/mgcreat. Pregnant women had the lowest positive samples per category (40% for day 1 and 43% for day 2, respectively), low mean levels of total DON (down to 2.84 ng/mgcreat) and median equal to 0 ng/mgcreat. Estimation of DON dietary intake reveals that 7.5% of the total population exceeds the TDI of 1 μg/kg bw/day set for DON, with children showing 40% of individuals surpassing this value (male, day 2).
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Affiliation(s)
- Barbara De Santis
- Reparto di Sicurezza Chimica degli Alimenti, Istituto Superiore di Sanità, 00161 Rome, Italy.
| | - Francesca Debegnach
- Reparto di Sicurezza Chimica degli Alimenti, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Brunella Miano
- Laboratorio di Chimica Sperimentale, Istituto Zooprofilattico Sperimentale delle Venezie, 35020 Legnaro (PD), Italy
| | - Giorgio Moretti
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, 06126 Perugia, Italy
| | - Elisa Sonego
- Reparto di Sicurezza Chimica degli Alimenti, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Antonio Chiaretti
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma-Italia-Università Cattolica del Sacro Cuore, 00168 Roma, Italy
| | - Danilo Buonsenso
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma-Italia-Università Cattolica del Sacro Cuore, 00168 Roma, Italy
| | - Carlo Brera
- Reparto di Sicurezza Chimica degli Alimenti, Istituto Superiore di Sanità, 00161 Rome, Italy
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Weber AM, Mawodza T, Sarkar B, Menon M. Assessment of potentially toxic trace element contamination in urban allotment soils and their uptake by onions: A preliminary case study from Sheffield, England. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 170:156-165. [PMID: 30529614 DOI: 10.1016/j.ecoenv.2018.11.090] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 11/17/2018] [Accepted: 11/19/2018] [Indexed: 05/23/2023]
Abstract
Toxic trace element (TTE) contamination in urban soils may pose potential health risks, especially in cities with previous industrial activities. This study aimed to investigate soil contamination in urban allotments in Sheffield, the uptake of TTEs in autumn and spring sown onions (Allium cepa), and their potential risks on human health via consumption of the crops. Paired soil and plant samples were taken in triplicates from four private allotments to assess potentially elevated levels of lead (Pb), zinc (Zn), copper (Cu), arsenic (As), and chromium (Cr). These elements in soils exceeded the ambient background levels for England. Both Pb and As exceeded some UK and EU soil tolerable limits. Concentration factors (CF) were calculated as the ratio of trace element in the plant as compared to that in the soil, and uptake rates were in the order Zn>Cu>Cr>Pb>As. Concentrations were higher for most TTEs in spring sown onions (SSO), and had significantly higher CF (p < 0.05) for Pb and Cr than autumn sown onions (ASO), whereas the opposite was true for As. Toxic elements in plants did not exceed FAO/WHO intake limits when considering TTE content per plant and consumption rates. Human health risk assessment calculations using target hazard quotients (THQ) and hazard indexes (HI) indicated that consuming onions alone did not pose an immediate health risk.
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Affiliation(s)
- Annika M Weber
- Department of Oncology and Metabolism, The Medical School, The University of Sheffield, Beech Hill Road, Sheffield S10 2RX, United Kingdom.
| | - Tinashe Mawodza
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Binoy Sarkar
- Leverhulme Centre for Climate Change Mitigation, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, United Kingdom; Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Manoj Menon
- Department of Geography, The University of Sheffield, Sheffield S10 2TN, United Kingdom
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Mise N, Ohtsu M, Ikegami A, Mizuno A, Cui X, Kobayashi Y, Nakagi Y, Nohara K, Yoshida T, Kayama F. Hijiki seaweed consumption elevates levels of inorganic arsenic intake in Japanese children and pregnant women. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2019; 36:84-95. [DOI: 10.1080/19440049.2018.1562228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Nathan Mise
- Department of Environmental and Preventive Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Mayumi Ohtsu
- Department of Environmental and Preventive Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Akihiko Ikegami
- Department of Environmental and Preventive Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Atsuko Mizuno
- Department of Pharmacology, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Xiaoyi Cui
- Department of Environmental and Preventive Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Yayoi Kobayashi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Yoshihiko Nakagi
- Department of Health Science, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Keiko Nohara
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Takahiko Yoshida
- Department of Health Science, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Fujio Kayama
- Department of Environmental and Preventive Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
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Kouda K, Iki M, Fujita Y, Nakamura H, Ohara K, Tachiki T, Nishiyama T. Trends in Serum Lipid Levels of a 10- and 13-Year-Old Population in Fukuroi City, Japan (2007-2017). J Epidemiol 2018; 30:24-29. [PMID: 30555117 PMCID: PMC6908840 DOI: 10.2188/jea.je20180164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Current trends in serum lipid levels among children are likely to be important predictors of future cardiovascular disease prevalence. However, no studies have examined trends in low-density lipoprotein cholesterol (LDL-C) levels in Japanese children. Methods We investigated trends in LDL-C levels from 2008 through 2017 and HDL-C levels from 2007 through 2017 in a population of 10- and 13-year-old children in Fukuroi City, Japan. We analyzed 17,838 children, accounting for 93.8% of all fifth and eighth graders in the entire city. Adverse lipid levels were defined as follows: 130 mg/dL or higher for LDL-C, and lower than 40 mg/dL for HDL-C. The Jonckheere-Terpstra and Cochran-Armitage tests were used to evaluate secular trends in mean serum lipid levels and prevalence of dyslipidemia, respectively. Results There were no significant trends in BMI during the study period. In children aged 10 years, serum levels of LDL-C and HDL-C showed significant positive associations with calendar year during the study period for both sexes. A significant increase in HDL-C levels was observed in girls aged 13 years. On the other hand, no significant trends were observed in the prevalence of high LDL-C or low HDL-C regardless of sex or age, while the prevalence of high non-HDL-C showed a significant increase in boys. Conclusions In the Fukuroi population, serum levels of LDL-C and HDL-C slightly increased in both boys and girls aged 10 years, and HDL-C levels slightly increased in girls aged 13 years, during the past decade.
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Affiliation(s)
- Katsuyasu Kouda
- Department of Hygiene and Public Health, Kansai Medical University
| | - Masayuki Iki
- Department of Public Health, Kindai University Faculty of Medicine
| | - Yuki Fujita
- Department of Public Health, Kindai University Faculty of Medicine
| | - Harunobu Nakamura
- Department of Health Promotion and Education, Graduate School of Human Development and Environment, Kobe University
| | - Kumiko Ohara
- Department of Health Promotion and Education, Graduate School of Human Development and Environment, Kobe University
| | - Takahiro Tachiki
- Department of Public Health, Kindai University Faculty of Medicine
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Resnik DB, MacDougall DR, Smith EM. Ethical Dilemmas in Protecting Susceptible Subpopulations From Environmental Health Risks: Liberty, Utility, Fairness, and Accountability for Reasonableness. THE AMERICAN JOURNAL OF BIOETHICS : AJOB 2018; 18:29-41. [PMID: 29466133 PMCID: PMC5884073 DOI: 10.1080/15265161.2017.1418922] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Various U.S. laws, such as the Clean Air Act and the Food Quality Protection Act, require additional protections for susceptible subpopulations who face greater environmental health risks. The main ethical rationale for providing these protections is to ensure that environmental health risks are distributed fairly. In this article, we (1) consider how several influential theories of justice deal with issues related to the distribution of environmental health risks; (2) show that these theories often fail to provide specific guidance concerning policy choices; and (3) argue that an approach to public decision making known as accountability for reasonableness can complement theories of justice in establishing acceptable environmental health risks for the general population and susceptible subpopulations. Since accountability for reasonableness focuses on the fairness of the decision-making process, not the outcome, it does not guarantee that susceptible subpopulations will receive a maximum level of protection, regardless of costs or other morally relevant considerations.
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Affiliation(s)
| | | | - Elise M Smith
- c National Institute of Environmental Health Sciences
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14
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Bell SM, Chang X, Wambaugh JF, Allen DG, Bartels M, Brouwer KLR, Casey WM, Choksi N, Ferguson SS, Fraczkiewicz G, Jarabek AM, Ke A, Lumen A, Lynn SG, Paini A, Price PS, Ring C, Simon TW, Sipes NS, Sprankle CS, Strickland J, Troutman J, Wetmore BA, Kleinstreuer NC. In vitro to in vivo extrapolation for high throughput prioritization and decision making. Toxicol In Vitro 2017; 47:213-227. [PMID: 29203341 DOI: 10.1016/j.tiv.2017.11.016] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 01/10/2023]
Abstract
In vitro chemical safety testing methods offer the potential for efficient and economical tools to provide relevant assessments of human health risk. To realize this potential, methods are needed to relate in vitro effects to in vivo responses, i.e., in vitro to in vivo extrapolation (IVIVE). Currently available IVIVE approaches need to be refined before they can be utilized for regulatory decision-making. To explore the capabilities and limitations of IVIVE within this context, the U.S. Environmental Protection Agency Office of Research and Development and the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods co-organized a workshop and webinar series. Here, we integrate content from the webinars and workshop to discuss activities and resources that would promote inclusion of IVIVE in regulatory decision-making. We discuss properties of models that successfully generate predictions of in vivo doses from effective in vitro concentration, including the experimental systems that provide input parameters for these models, areas of success, and areas for improvement to reduce model uncertainty. Finally, we provide case studies on the uses of IVIVE in safety assessments, which highlight the respective differences, information requirements, and outcomes across various approaches when applied for decision-making.
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Affiliation(s)
- Shannon M Bell
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | - Xiaoqing Chang
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | - John F Wambaugh
- U.S. Environmental Protection Agency, 109 T.W. Alexander Dr., Research Triangle Park, NC 27709, USA.
| | - David G Allen
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | | | - Kim L R Brouwer
- UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Campus Box 7569, Chapel Hill, NC 27599, USA.
| | - Warren M Casey
- National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
| | - Neepa Choksi
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | - Stephen S Ferguson
- National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
| | | | - Annie M Jarabek
- U.S. Environmental Protection Agency, 109 T.W. Alexander Dr., Research Triangle Park, NC 27709, USA.
| | - Alice Ke
- Simcyp Limited (a Certara company), John Street, Sheffield, S2 4SU, United Kingdom.
| | - Annie Lumen
- National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA.
| | - Scott G Lynn
- U.S. Environmental Protection Agency, William Jefferson Clinton Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, USA.
| | - Alicia Paini
- European Commission, Joint Research Centre, Directorate Health, Consumers and Reference Materials, Chemical Safety and Alternative Methods Unit incorporating EURL ECVAM, Via E. Fermi 2749, Ispra, Varese 20127, Italy.
| | - Paul S Price
- U.S. Environmental Protection Agency, 109 T.W. Alexander Dr., Research Triangle Park, NC 27709, USA.
| | - Caroline Ring
- Oak Ridge Institute for Science and Education, P.O. Box 2008, Oak Ridge, TN 37831, USA.
| | - Ted W Simon
- Ted Simon LLC, 4184 Johnston Road, Winston, GA 30187, USA.
| | - Nisha S Sipes
- National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
| | - Catherine S Sprankle
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | - Judy Strickland
- Integrated Laboratory Systems, Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
| | - John Troutman
- Central Product Safety, The Procter & Gamble Company, Cincinnati, OH 45202, USA.
| | - Barbara A Wetmore
- ScitoVation LLC, 6 Davis Drive, Research Triangle Park, NC 27709, USA.
| | - Nicole C Kleinstreuer
- National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
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Ferguson A, Penney R, Solo-Gabriele H. A Review of the Field on Children's Exposure to Environmental Contaminants: A Risk Assessment Approach. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E265. [PMID: 28273865 PMCID: PMC5369101 DOI: 10.3390/ijerph14030265] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/21/2017] [Accepted: 02/25/2017] [Indexed: 01/21/2023]
Abstract
Background: Children must be recognized as a sensitive population based on having biological systems and organs in various stages of development. The processes of absorption, distribution, metabolism and elimination of environmental contaminants within a child's body are considered less advanced than those of adults, making them more susceptible to disease outcomes following even small doses. Children's unique activities of crawling and practicing increased hand-to-mouth ingestion also make them vulnerable to greater exposures by certain contaminants within specific environments. Approach: There is a need to review the field of children's environmental exposures in order to understand trends and identify gaps in research, which may lead to better protection of this vulnerable and sensitive population. Therefore, explored here are previously published contemporary works in the broad area of children's environmental exposures and potential impact on health from around the world. A discussion of children's exposure to environmental contaminants is best organized under the last four steps of a risk assessment approach: hazard identification, dose-response assessment, exposure assessment (including children's activity patterns) and risk characterization. We first consider the many exposure hazards that exist in the indoor and outdoor environments, and emerging contaminants of concern that may help guide the risk assessment process in identifying focus areas for children. A section on special diseases of concern is also included. Conclusions: The field of children's exposures to environmental contaminants is broad. Although there are some well-studied areas offering much insight into children exposures, research is still needed to further our understanding of exposures to newer compounds, growing disease trends and the role of gene-environment interactions that modify adverse health outcomes. It is clear that behaviors of adults and children play a role in reducing or increasing a child's exposure, where strategies to better communicate and implement risk modifying behaviors are needed, and can be more effective than implementing changes in the physical environment.
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Affiliation(s)
- Alesia Ferguson
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 820, Little Rock, AR 72205, USA.
| | - Rosalind Penney
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 820, Little Rock, AR 72205, USA.
| | - Helena Solo-Gabriele
- Department of Civil, Architectural, and Environmental Engineering, College of Engineering, University of Miami, Florida, 1251 Memorial Drive, Coral Gables, FL 33146, USA.
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Abstract
A pediatric assessment is now a required component of every drug marketing application in North America, Europe, and Japan, unless a waiver has been granted previously. Nonclinical juvenile toxicity studies are often required as part of this assessment. The protocols for juvenile toxicity studies are best devised in consultation with the regulatory authorities. It is important to submit the pediatric investigation plan (PIP) or pediatric study plan (PSP) early, in order not to delay the marketing authorization of the drug in adults. The choice of species and the design of juvenile toxicity studies are based on a series of complex considerations, including the therapeutic use of the drug, age at which children will be treated, duration of treatment, and potential age- or species-specific differences in efficacy, pharmacokinetics, or toxicity.
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Children's Exposure to Environmental Contaminants: An Editorial Reflection of Articles in the IJERPH Special Issue Entitled, "Children's Exposure to Environmental Contaminants". INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13111117. [PMID: 27834888 PMCID: PMC5129327 DOI: 10.3390/ijerph13111117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 12/16/2022]
Abstract
Children are at increased vulnerability to many environmental contaminants compared to adults due to their unique behavior patterns, increased contaminant intake per body weight, and developing biological systems. Depending upon their age, young children may crawl on the floor and may practice increased hand to mouth activity that may increase their dose-intake of specific contaminants that accumulate in dust and other matrices. Children are also smaller in size than adults, resulting in a greater body burden for a given contaminant dose. Because children undergo rapid transitions through particular developmental stages they are also especially vulnerable during certain growth-related time windows. A Special Issue was organized focused on the latest findings in the field of children’s environmental exposure for these reasons. This editorial introduces articles in this Special Issue and emphasizes their main findings in advancing the field. From the many articles submitted to this Special Issue from around the world, 23 were accepted and published. They focus on a variety of research areas such as children’s activity patterns, improved risk assessment methods to estimate exposures, and exposures in various contexts and to various contaminants. The future health of a nation relies on protecting the children from adverse exposures and understanding the etiology of childhood diseases. The field of children’s environmental exposures must consider improved and comprehensive research methods aimed at introducing mitigation strategies locally, nationally, and globally. We are happy to introduce a Special Issue focused on children’s environmental exposure and children’s health and hope that it contributes towards improved health of children.
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18
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The immature rat as a potential model for chemical risks to children: Ontogeny of selected hepatic P450s. Chem Biol Interact 2016; 256:167-77. [DOI: 10.1016/j.cbi.2016.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/02/2016] [Accepted: 07/03/2016] [Indexed: 11/24/2022]
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Loh MM, Sugeng A, Lothrop N, Klimecki W, Cox M, Wilkinson ST, Lu Z, Beamer PI. Multimedia exposures to arsenic and lead for children near an inactive mine tailings and smelter site. ENVIRONMENTAL RESEARCH 2016; 146:331-9. [PMID: 26803211 PMCID: PMC5344033 DOI: 10.1016/j.envres.2015.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Revised: 12/06/2015] [Accepted: 12/10/2015] [Indexed: 05/20/2023]
Abstract
Children living near contaminated mining waste areas may have high exposures to metals from the environment. This study investigates whether exposure to arsenic and lead is higher in children in a community near a legacy mine and smelter site in Arizona compared to children in other parts of the United States and the relationship of that exposure to the site. Arsenic and lead were measured in residential soil, house dust, tap water, urine, and toenail samples from 70 children in 34 households up to 7 miles from the site. Soil and house dust were sieved, digested, and analyzed via ICP-MS. Tap water and urine were analyzed without digestion, while toenails were washed, digested and analyzed. Blood lead was analyzed by an independent, certified laboratory. Spearman correlation coefficients were calculated between each environmental media and urine and toenails for arsenic and lead. Geometric mean arsenic (standard deviation) concentrations for each matrix were: 22.1 (2.59) ppm and 12.4 (2.27)ppm for soil and house dust (<63μm), 5.71 (6.55)ppb for tap water, 14.0 (2.01)μg/L for specific gravity-corrected total urinary arsenic, 0.543 (3.22)ppm for toenails. Soil and vacuumed dust lead concentrations were 16.9 (2.03)ppm and 21.6 (1.90) ppm. The majority of blood lead levels were below the limit of quantification. Arsenic and lead concentrations in soil and house dust decreased with distance from the site. Concentrations in soil, house dust, tap water, along with floor dust loading were significantly associated with toenail and urinary arsenic but not lead. Mixed models showed that soil and tap water best predicted urinary arsenic. In our study, despite being present in mine tailings at similar levels, internal lead exposure was not high, but arsenic exposure was of concern, particularly from soil and tap water. Naturally occurring sources may be an additional important contributor to exposures in certain legacy mining areas.
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Affiliation(s)
- Miranda M Loh
- Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA.
| | - Anastasia Sugeng
- Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA
| | - Nathan Lothrop
- Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA
| | - Walter Klimecki
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, P.O. Box 210207, Tucson, AZ 85724, USA
| | - Melissa Cox
- Hospital Medicine and Outreach, Department of Pediatrics, Diamond Children's Medical Center, The University of Arizona, 1501 N. Campbell Ave. Tucson, AZ 85724, USA
| | - Sarah T Wilkinson
- Superfund Research Program, The University of Arizona, 1110 E. South Campus Dr., Tucson, AZ 85721, USA
| | - Zhenqiang Lu
- BIO5 Institute, The University of Arizona, 1657 E. Mabel St., Tucson, AZ 85721, USA
| | - Paloma I Beamer
- Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA
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Kirman CR, Aylward LL, Wetmore BA, Thomas RS, Sochaski M, Ferguson SS, Csiszar SA, Jolliet O. Quantitative Property–Property Relationship for Screening-Level Prediction of Intrinsic Clearance: A Tool for Exposure Modeling for High-Throughput Toxicity Screening Data. ACTA ACUST UNITED AC 2015. [DOI: 10.1089/aivt.2014.0008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | | | - Barbara A. Wetmore
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Russell S. Thomas
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - M. Sochaski
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | | | - Susan A. Csiszar
- University of Michigan, School of Public Health, Ann Arbor, Michigan
| | - Olivier Jolliet
- University of Michigan, School of Public Health, Ann Arbor, Michigan
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21
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Multifactorial Origin of Neurodevelopmental Disorders: Approaches to Understanding Complex Etiologies. TOXICS 2015; 3:89-129. [PMID: 29056653 PMCID: PMC5634696 DOI: 10.3390/toxics3010089] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 03/06/2015] [Accepted: 03/18/2015] [Indexed: 12/12/2022]
Abstract
A significant body of evidence supports the multifactorial etiology of neurodevelopmental disorders (NDDs) affecting children. The present review focuses on early exposure to environmental chemicals as a risk factor for neurodevelopment, and presents the major lines of evidence derived from epidemiological studies, underlying key uncertainties and research needs in this field. We introduce the exposome concept that, encompassing the totality of human environmental exposures to multiple risk factors, aims at explaining individual vulnerability and resilience to early chemical exposure. In this framework, we synthetically review the role of variable gene backgrounds, the involvement of epigenetic mechanisms as well as the function played by potential effect modifiers such as socioeconomic status. We describe laboratory rodent studies where the neurodevelopmental effects of environmental chemicals are assessed in the presence of either a “vulnerable” gene background or adverse pregnancy conditions (i.e., maternal stress). Finally, we discuss the need for more descriptive and “lifelike” experimental models of NDDs, to identify candidate biomarkers and pinpoint susceptible groups or life stages to be translated to large prospective studies within the exposome framework.
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Felter SP, Daston GP, Euling SY, Piersma AH, Tassinari MS. Assessment of health risks resulting from early-life exposures: Are current chemical toxicity testing protocols and risk assessment methods adequate? Crit Rev Toxicol 2015; 45:219-44. [PMID: 25687245 DOI: 10.3109/10408444.2014.993919] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract Over the last couple of decades, the awareness of the potential health impacts associated with early-life exposures has increased. Global regulatory approaches to chemical risk assessment are intended to be protective for the diverse human population including all life stages. However, questions persist as to whether the current testing approaches and risk assessment methodologies are adequately protective for infants and children. Here, we review physiological and developmental differences that may result in differential sensitivity associated with early-life exposures. It is clear that sensitivity to chemical exposures during early-life can be similar, higher, or lower than that of adults, and can change quickly within a short developmental timeframe. Moreover, age-related exposure differences provide an important consideration for overall susceptibility. Differential sensitivity associated with a life stage can reflect the toxicokinetic handling of a xenobiotic exposure, the toxicodynamic response, or both. Each of these is illustrated with chemical-specific examples. The adequacy of current testing protocols, proposed new tools, and risk assessment methods for systemic noncancer endpoints are reviewed in light of the potential for differential risk to infants and young children.
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Vrijheid M, Slama R, Robinson O, Chatzi L, Coen M, van den Hazel P, Thomsen C, Wright J, Athersuch TJ, Avellana N, Basagaña X, Brochot C, Bucchini L, Bustamante M, Carracedo A, Casas M, Estivill X, Fairley L, van Gent D, Gonzalez JR, Granum B, Gražulevičienė R, Gutzkow KB, Julvez J, Keun HC, Kogevinas M, McEachan RRC, Meltzer HM, Sabidó E, Schwarze PE, Siroux V, Sunyer J, Want EJ, Zeman F, Nieuwenhuijsen MJ. The human early-life exposome (HELIX): project rationale and design. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:535-44. [PMID: 24610234 PMCID: PMC4048258 DOI: 10.1289/ehp.1307204] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 03/06/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure-health effect relationships. The "exposome" concept encompasses the totality of exposures from conception onward, complementing the genome. OBJECTIVES The Human Early-Life Exposome (HELIX) project is a new collaborative research project that aims to implement novel exposure assessment and biomarker methods to characterize early-life exposure to multiple environmental factors and associate these with omics biomarkers and child health outcomes, thus characterizing the "early-life exposome." Here we describe the general design of the project. METHODS In six existing birth cohort studies in Europe, HELIX will estimate prenatal and postnatal exposure to a broad range of chemical and physical exposures. Exposure models will be developed for the full cohorts totaling 32,000 mother-child pairs, and biomarkers will be measured in a subset of 1,200 mother-child pairs. Nested repeat-sampling panel studies (n = 150) will collect data on biomarker variability, use smartphones to assess mobility and physical activity, and perform personal exposure monitoring. Omics techniques will determine molecular profiles (metabolome, proteome, transcriptome, epigenome) associated with exposures. Statistical methods for multiple exposures will provide exposure-response estimates for fetal and child growth, obesity, neurodevelopment, and respiratory outcomes. A health impact assessment exercise will evaluate risks and benefits of combined exposures. CONCLUSIONS HELIX is one of the first attempts to describe the early-life exposome of European populations and unravel its relation to omics markers and health in childhood. As proof of concept, it will form an important first step toward the life-course exposome.
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Affiliation(s)
- Martine Vrijheid
- Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain
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Valcke M, Krishnan K. Characterization of the human kinetic adjustment factor for the health risk assessment of environmental contaminants. J Appl Toxicol 2013; 34:227-40. [PMID: 24038072 DOI: 10.1002/jat.2919] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 07/15/2013] [Indexed: 12/26/2022]
Abstract
A default uncertainty factor of 3.16 (√10) is applied to account for interindividual variability in toxicokinetics when performing non-cancer risk assessments. Using relevant human data for specific chemicals, as WHO/IPCS suggests, it is possible to evaluate, and replace when appropriate, this default factor by quantifying chemical-specific adjustment factors for interindividual variability in toxicokinetics (also referred to as the human kinetic adjustment factor, HKAF). The HKAF has been determined based on the distributions of pharmacokinetic parameters (e.g., half-life, area under the curve, maximum blood concentration) in relevant populations. This article focuses on the current state of knowledge of the use of physiologically based algorithms and models in characterizing the HKAF for environmental contaminants. The recent modeling efforts on the computation of HKAF as a function of the characteristics of the population, chemical and its mode of action (dose metrics), as well as exposure scenario of relevance to the assessment are reviewed here. The results of these studies, taken together, suggest the HKAF varies as a function of the sensitive subpopulation and dose metrics of interest, exposure conditions considered (route, duration, and intensity), metabolic pathways involved and theoretical model underlying its computation. The HKAF seldom exceeded the default value of 3.16, except in very young children (i.e., <≈ 3 months) and when the parent compound is the toxic moiety. Overall, from a public health perspective, the current state of knowledge generally suggest that the default uncertainty factor is sufficient to account for human variability in non-cancer risk assessments of environmental contaminants.
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Affiliation(s)
- Mathieu Valcke
- Département de santé environnementale et santé au travail, Université de Montréal, CP 6128, Succursale Centre-Ville, Montréal, Québec, Canada, H3C 3 J7; Institut national de santé publique du Québec, 190 Boul. Crémazie Est, Montréal, QC, Canada, H2P 1E2
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Woods JS, Heyer NJ, Russo JE, Martin MD, Pillai PB, Farin FM. Modification of neurobehavioral effects of mercury by genetic polymorphisms of metallothionein in children. Neurotoxicol Teratol 2013; 39:36-44. [PMID: 23827881 DOI: 10.1016/j.ntt.2013.06.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 06/13/2013] [Accepted: 06/19/2013] [Indexed: 01/02/2023]
Abstract
Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that genetic variants of metallothionein (MT) that are reported to affect Hg toxicokinetics in adults would modify the neurotoxic effects of Hg in children. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary Hg levels. Following the completion of the clinical trial, we performed genotyping assays for variants of MT isoforms MT1M (rs2270837) and MT2A (rs10636) on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between allelic status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant interactions or independent main effects for Hg exposure and either of the MT gene variants were observed. In contrast, among boys, numerous significant interaction effects between variants of MT1M and MT2A, alone and combined, with Hg exposure were observed spanning multiple domains of neurobehavioral function. All dose-response associations between Hg exposure and test performance were restricted to boys and were in the direction of impaired performance. These findings suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children with relatively common genetic variants of MT, and may have important public health implications for future strategies aimed at protecting children and adolescents from the potential health risks associated with Hg exposure. We note that because urinary Hg reflects a composite exposure index that cannot be attributed to a specific source, these findings do not support an association between Hg in dental amalgams specifically and the adverse neurobehavioral outcomes observed.
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Affiliation(s)
- James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
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Soellner L, Olejniczak K. The need for juvenile animal studies – A critical review. Regul Toxicol Pharmacol 2013; 65:87-99. [DOI: 10.1016/j.yrtph.2012.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/10/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
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Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol 2012; 34:513-21. [PMID: 22765978 DOI: 10.1016/j.ntt.2012.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that CPOX4, a genetic variant of the heme pathway enzyme coproporphyrinogen oxidase (CPOX) that affects susceptibility to mercury toxicity in adults, also modifies the neurotoxic effects of Hg in children. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings in children. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary mercury levels. Following the completion of the clinical trial, genotyping assays for CPOX4 allelic status were performed on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between CPOX4 status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant CPOX4-Hg interactions or independent main effects for Hg or CPOX4 were observed. In contrast, among boys, numerous significant interaction effects between CPOX4 and Hg were observed spanning all 5 domains of neurobehavioral performance. All underlying dose-response associations between Hg exposure and test performance were restricted to boys with the CPOX4 variant, and all of these associations were in the expected direction where increased exposure to Hg decreased performance. These findings are the first to demonstrate genetic susceptibility to the adverse neurobehavioral effects of Hg exposure in children. The paucity of responses among same-age girls with comparable Hg exposure provides evidence of sexual dimorphism in genetic susceptibility to the adverse neurobehavioral effects of Hg in children and adolescents.
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Affiliation(s)
- James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
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Royland JE, Kodavanti PRS, Schmid JE, MacPhail RC. Toluene effects on gene expression in the hippocampus of young adult, middle-age, and senescent Brown Norway Rats. Toxicol Sci 2011; 126:193-212. [PMID: 22166486 DOI: 10.1093/toxsci/kfr340] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Differential susceptibility to environmental exposures across life stages is an area of toxicology about which little is known. We examined the effects of toluene on transcriptomic changes and oxidative stress (OS) parameters (e.g., NQO1 and GPX) in the rat brain at different life stages to elucidate key molecular pathways responsible for toluene-induced neurotoxicity, as well as possible age-related interactions. Changes in assessed end points following acute oral toluene (0, 0.65, and 1.0 g/kg) were examined 4 h after exposure in hippocampi of Brown Norway Rats at 4, 12, and 24 months of age. Genomic data were analyzed by two-way ANOVA to identify the effects of age, toluene, and interactions between the two factors. Analysis by one-way ANOVA identified 183 genes whose expression changed ≥ 1.25-fold with age. The majority of the genes were upregulated between life stages (> 79%). Similar analysis for toluene-related genes found only two sequences to vary significantly with dose. Fifty-six genes were identified to have expression changes due to an age-toluene interaction. Expression of genes with roles in immune response, cytoskeleton, protein, and energy metabolism was changed with advancing life stage, indicating changes in basic cellular homeostasis. Toluene affected similar cell functions, enhancing the effects of aging. OS parameters also indicated age-related changes in response mechanisms, evidence of toluene damage, and supported an age-toluene interaction. The data indicate that life stage can alter the toxicity of acute toluene exposure in various and complex ways, highlighting the need for further investigation into the role of aging in susceptibility.
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Affiliation(s)
- Joyce E Royland
- Genetic and Cellular Toxicology Branch, Integrated Systems Toxicology Division, U.S.Environmental Protection Agency, Durham, NC 27711, USA.
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Bonnefoi MS, Belanger SE, Devlin DJ, Doerrer NG, Embry MR, Fukushima S, Harpur ES, Hines RN, Holsapple MP, Kim JH, MacDonald JS, O’Lone R, Pettit SD, Stevens JL, Takei AS, Tinkle SS, van der Laan JW. Human and environmental health challenges for the next decade (2010–2020). Crit Rev Toxicol 2010; 40:893-911. [DOI: 10.3109/10408444.2010.506640] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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