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Guo Y, Yang Y, Li R, Liao X, Li Y. Cadmium accumulation in tropical island paddy soils: From environment and health risk assessment to model prediction. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133212. [PMID: 38101012 DOI: 10.1016/j.jhazmat.2023.133212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/22/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023]
Abstract
Cultivated soil quality is crucial because it directly affects food safety and human health, and rice is of primary concern because of its centrality to global food networks. However, a detailed understanding of cadmium (Cd) geochemical cycling in paddy soils is complicated by the multiple influencing factors present in many rice-growing areas that overlap with industrial centers. This study analyzed the pollution characteristics and health risks of Cd in paddy soils across Hainan Island and identified key influencing factors based on multi-source environmental data and prediction models. Approximately 27.07% of the soil samples exceeded the risk control standard screening value for Cd in China, posing an uncontaminated to moderate contamination risk. Cd concentration and exposure duration contributed the most to non-carcinogenic and carcinogenic risks to children, teens, and adults through ingestion. Among the nine prediction models tested, Extreme Gradient Boosting (XGBoost) exhibited the best performance for Cd prediction with soil properties having the highest importance, followed by climatic variables and topographic attributes. In summary, XGBoost reliably predicted the soil Cd concentrations on tropical islands. Further research should incorporate additional soil properties and environmental variables for more accurate predictions and to comprehensively identify their driving factors and corresponding contribution rates.
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Affiliation(s)
- Yan Guo
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruxia Li
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyong Liao
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yonghua Li
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
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Tohon H, Valcke M, Aranda-Rodriguez R, Nong A, Haddad S. Estimation of toluene exposure in air from BMA (S-benzylmercapturic acid) urinary measures using a reverse dosimetry approach based on physiologically pharmacokinetic modeling. Regul Toxicol Pharmacol 2021; 120:104860. [PMID: 33406392 DOI: 10.1016/j.yrtph.2020.104860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/14/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
This study aimed to use a reverse dosimetry PBPK modeling approach to estimate toluene atmospheric exposure from urinary measurements of S-benzylmercapturic acid (BMA) in a small group of individuals and to evaluate the uncertainty associated to urinary spot-sampling compared to 24-h collected urine samples. Each exposure assessment technique was developed namely to estimate toluene air exposure from BMA measurements in 24-h urine samples (24-h-BMA) and from distributions of daily urinary BMA spot measurements (DUBSM). Model physiological parameters were described based upon age, weight, size and sex. Monte Carlo simulations with the PBPK model allowed converting DUBSM distribution (and 24-h-BMA) into toluene air levels. For the approach relying on DUBSM distribution, the ratio between the 95% probability of predicted toluene concentration and its 50% probability in each individual varied between 1.2 and 1.4, while that based on 24-h-BMA varied between 1.0 and 1.1. This suggests more variability in estimated exposure from spot measurements. Thus, estimating toluene exposure based on DUBSM distribution generated about 20% more uncertainty. Toluene levels estimated (0.0078-0.0138 ppm) are well below Health Canada's maximum chronic air guidelines. PBPK modeling and reverse dosimetry may be combined to interpret urinary metabolites data of VOCs and assess related uncertainties.
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Affiliation(s)
- Honesty Tohon
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada
| | - Mathieu Valcke
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada; Direction de la santé environnementale et de la toxicologie, Institut national de santé publique du Québec, Montréal, Quebec, Canada
| | - Rocio Aranda-Rodriguez
- Exposure and Biomonitoring Division, Environmental Health Sciences and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Andy Nong
- Exposure and Biomonitoring Division, Environmental Health Sciences and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Sami Haddad
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada.
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Linakis MW, Sayre RR, Pearce RG, Sfeir MA, Sipes NS, Pangburn HA, Gearhart JM, Wambaugh JF. Development and evaluation of a high throughput inhalation model for organic chemicals. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2020; 30:866-877. [PMID: 32546826 PMCID: PMC7483974 DOI: 10.1038/s41370-020-0238-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/27/2020] [Accepted: 06/03/2020] [Indexed: 05/12/2023]
Abstract
Currently it is difficult to prospectively estimate human toxicokinetics (particularly for novel chemicals) in a high-throughput manner. The R software package httk has been developed, in part, to address this deficiency, and the aim of this investigation was to develop a generalized inhalation model for httk. The structure of the inhalation model was developed from two previously published physiologically based models from Jongeneelen and Berge (Ann Occup Hyg 55:841-864, 2011) and Clewell et al. (Toxicol Sci 63:160-172, 2001), while calculated physicochemical data was obtained from EPA's CompTox Chemicals Dashboard. In total, 142 exposure scenarios across 41 volatile organic chemicals were modeled and compared to published data. The slope of the regression line of best fit between log-transformed simulated and observed blood and exhaled breath concentrations was 0.46 with an r2 = 0.45 and a root mean square error (RMSE) of direct comparison between the log-transformed simulated and observed values of 1.11. Approximately 5.1% (n = 108) of the data points analyzed were >2 orders of magnitude different than expected. The volatile organic chemicals examined in this investigation represent small, generally lipophilic molecules. Ultimately this paper details a generalized inhalation component that integrates with the httk physiologically based toxicokinetic model to provide high-throughput estimates of inhalation chemical exposures.
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Affiliation(s)
- Matthew W Linakis
- United States Air Force, 711th Human Performance Wing, Airman Readiness Optimization, Wright-Patterson AFB, Wright-Patterson AFB, OH, 45433, USA
- UES, Inc., Dayton, OH, 45432, USA
| | - Risa R Sayre
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37831, USA
- National Center for Computational Toxicology, United States Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Robert G Pearce
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37831, USA
- National Center for Computational Toxicology, United States Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Mark A Sfeir
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37831, USA
- National Center for Computational Toxicology, United States Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Nisha S Sipes
- National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27711, USA
| | - Heather A Pangburn
- United States Air Force, 711th Human Performance Wing, Molecular Bioeffects, Wright-Patterson AFB, Wright-Patterson AFB, OH, 45433, USA
| | - Jeffery M Gearhart
- United States Air Force, 711th Human Performance Wing, Airman Readiness Optimization, Wright-Patterson AFB, Wright-Patterson AFB, OH, 45433, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Wright-Patterson AFB, Wright-Patterson AFB, OH, 45433, USA
| | - John F Wambaugh
- National Center for Computational Toxicology, United States Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.
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Faure S, Noisel N, Werry K, Karthikeyan S, Aylward LL, St-Amand A. Evaluation of human biomonitoring data in a health risk based context: An updated analysis of population level data from the Canadian Health Measures Survey. Int J Hyg Environ Health 2019; 223:267-280. [PMID: 31523017 DOI: 10.1016/j.ijheh.2019.07.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/19/2019] [Accepted: 07/20/2019] [Indexed: 11/28/2022]
Abstract
In order to characterize exposure of the Canadian population to environmental chemicals, a human biomonitoring component has been included in the Canadian Health Measures Survey (CHMS). This nationally-representative survey, launched in 2007 by the Government of Canada, has measured over 250 chemicals in approximately 30,000 Canadians during the last decade. The capacity to interpret these data at the population level in a health risk context is gradually improving with the development of biomonitoring screening values, such as biomonitoring equivalents (BE) and human biomonitoring (HBM) values. This study evaluates recent population level biomonitoring data from the CHMS in a health risk context using biomonitoring screening values. Nationally representative biomonitoring data for fluoride, selenium, molybdenum, arsenic, silver, thallium, cyfluthrin, 2,4-dichlorophenoxyacetic acid (2,4-D), 3-phenoxybenzoic acid (3-PBA), chlorpyrifos, deltamethrin, bisphenol A, triclosan, acrylamide, cadmium, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), bromoform, chloroform, benzene, toluene, xylene, ethylbenzene, styrene and tetrachloroethylene were screened as part as this study. For non-cancer endpoints, hazard quotients (HQs) were calculated as the ratio of population level concentrations of a specific chemical at the geometric mean and 95th percentile to the corresponding biomonitoring screening value. Cancer risks were calculated at the 5th, 25th, 50th, 75th and 95th percentiles of the population concentration using BEs based on a risk specific dose. Most of the chemicals analyzed had HQs below 1 suggesting that levels of exposure to these chemicals are not a concern at the population level. However, HQs exceeded 1 in smokers for cadmium, acrylamide and benzene, as well as in the general population for inorganic arsenic, PFOS and PFOA, 3-PBA and fluoride. Furthermore, cancer risks for inorganic arsenic, acrylamide, and benzene at most population percentiles of exposure were elevated (>10-5). Specifically, for inorganic arsenic in the general population, the HQ was 3.13 at the 95th percentile concentration and the cancer risk was 3.4 × 10-4 at the 50th percentile of population concentrations. These results suggest that the levels of exposure in the Canadian population to some of the environmental chemicals assessed might be of concern. The results of this screening exercise support the findings of previous risk assessments and ongoing efforts to reduce risks from exposure to chemicals evaluated as part of this study. Although paucity of biomonitoring screening values for several environmental contaminants may be a limitation to this approach, our assessment contributes to the prioritization of a number of chemicals measured as part of CHMS for follow-up activities such as more detailed characterization of exposure sources.
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Affiliation(s)
- Sarah Faure
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada; Department of Environmental and Occupational Health, University of Montreal, Montreal, Quebec, Canada.
| | - Nolwenn Noisel
- Department of Environmental and Occupational Health, University of Montreal, Montreal, Quebec, Canada.
| | - Kate Werry
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada.
| | | | - Lesa L Aylward
- Summit Toxicology, LLP, Falls Church, VA, USA; Queensland Alliance for Environmental Health Sciences, University of Queensland, Brisbane, QLD, Australia.
| | - Annie St-Amand
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada.
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Banton MI, Bus JS, Collins JJ, Delzell E, Gelbke HP, Kester JE, Moore MM, Waites R, Sarang SS. Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2019; 22:1-130. [PMID: 31284836 DOI: 10.1080/10937404.2019.1633718] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.
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Affiliation(s)
- M I Banton
- a Gorge View Consulting LLC , Hood River , OR , USA
| | - J S Bus
- b Health Sciences , Exponent , Midland , MI , USA
| | - J J Collins
- c Health Sciences , Saginaw Valley State University , Saginaw , MI , USA
| | - E Delzell
- d Private consultant , Birmingham , AL , USA
| | | | - J E Kester
- f Kester Consulting LLC , Wentzville , MO , USA
| | | | - R Waites
- h Sabic , Innovative Plastics US LLC , Mount Vernon , IN , USA
| | - S S Sarang
- i Shell Health , Shell International , Houston , TX , USA
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Tohon H, Nong A, Moreau M, Valcke M, Haddad S. Reverse dosimetry modeling of toluene exposure concentrations based on biomonitoring levels from the Canadian health measures survey. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2018; 81:1066-1082. [PMID: 30365389 DOI: 10.1080/15287394.2018.1534174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/05/2018] [Accepted: 10/06/2018] [Indexed: 06/08/2023]
Abstract
Biomonitoring might provide useful estimates of population exposure to environmental chemicals. However, data uncertainties stemming from interindividual variability are common in large population biomonitoring surveys. Physiologically based pharmacokinetic (PBPK) models might be used to account for age- and gender-related variability in internal dose. The objective of this study was to reconstruct air concentrations consistent with blood toluene measures reported in the third Canadian Health Measures Survey using reverse dosimetry PBPK modeling techniques. Population distributions of model's physiological parameters were described based upon age, weight, and size for four subpopulations (12-19, 20-39, 40-59, and 60-79 years old). Monte Carlo simulations applied to PBPK modeling allowed converting the distributions of venous blood measures of toluene obtained from CHMS into related air levels. Based upon blood levels observed at the 50th, 90th and 95th percentiles, corresponding air toluene concentrations were estimated for teenagers aged 12-19 years as being, respectively, 0.009, 0.04 and 0.06 ppm. Similarly, values were computed for adults aged 20-39 years (0.007, 0.036, and 0.06 ppm), 40-59 years (0.007, 0.036 and 0.06 ppm) and 60-79 years (0.006, 0.022 and 0.04 ppm). These estimations are well below Health Canada's maximum recommended chronic air guidelines for toluene. In conclusion, PBPK modeling and reverse dosimetry may be combined to help interpret biomonitoring data for chemical exposure in large population surveys and estimate the associated toxicological health risk.
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Affiliation(s)
- Honesty Tohon
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
| | - Andy Nong
- b Exposure and Biomonitoring Division , Environmental Health Sciences and Research Bureau, Health Canada , Ottawa , ON , Canada
| | - Marjory Moreau
- b Exposure and Biomonitoring Division , Environmental Health Sciences and Research Bureau, Health Canada , Ottawa , ON , Canada
| | - Mathieu Valcke
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
- c Direction de la santé environnementale et de la toxicologie , Institut national de santé publique du Québec , Montréal , Quebec , Canada
| | - Sami Haddad
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
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Jean KJ, Wassef N, Gagnon F, Valcke M. A Physiologically-Based Pharmacokinetic Modeling Approach Using Biomonitoring Data in Order to Assess the Contribution of Drinking Water for the Achievement of an Optimal Fluoride Dose for Dental Health in Children. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E1358. [PMID: 29958421 PMCID: PMC6069276 DOI: 10.3390/ijerph15071358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 12/05/2022]
Abstract
Due to an optimal fluoride concentration in drinking water advised for caries prevention purposes, the population is now exposed to multiple sources of fluoride. The availability of population biomonitoring data currently allow us to evaluate the magnitude of this exposure. The objective of this work was, therefore, to use such data in order to estimate whether community water fluoridation still represents a significant contribution toward achieving a suggested daily optimal fluoride (external) intake of 0.05 mg/kg/day. Therefore, a physiologically-based pharmacokinetic model for fluoride published in the literature was used and adapted in Excel for a typical 4-year-old and 8-year-old child. Biomonitoring data from the Canadian Health Measures Survey among people living in provinces with very different drinking water fluoridation coverage (Quebec, 2.5%; Ontario, 70% of the population) were analyzed using this adapted model. Absorbed doses for the 4-year-old and 8-year-old children were, respectively, 0.03 mg/kg/day and 0.02 mg/kg/day in Quebec and of 0.06 mg/kg/day and 0.05 mg/kg/day in Ontario. These results show that community water fluoridation contributes to increased fluoride intake among children, which leads to reaching, and in some cases even exceeding, the suggested optimal absorbed dose of 0.04 mg/kg/day, which corresponds to the suggested optimal fluoride intake mentioned above. In conclusion, this study constitutes an incentive to further explore the multiple sources of fluoride intake and suggests that a new balance between them including drinking water should be examined in accordance with the age-related physiological differences that influence fluoride metabolism.
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Affiliation(s)
- Keven J Jean
- Institut National de Santé Publique du Québec (INSPQ), Montréal, QC H2P 1E2, Canada.
- Département de Santé Environnementale et Santé au Travail, École de Santé Publique de l'Université de Montréal (ESPUM), Montréal, QC H3C 3J7, Canada.
| | - Nancy Wassef
- Institut National de Santé Publique du Québec (INSPQ), Montréal, QC H2P 1E2, Canada.
| | - Fabien Gagnon
- Institut National de Santé Publique du Québec (INSPQ), Montréal, QC H2P 1E2, Canada.
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke (CRCHUS), Sherbrooke, QC J1H 5N4, Canada.
| | - Mathieu Valcke
- Institut National de Santé Publique du Québec (INSPQ), Montréal, QC H2P 1E2, Canada.
- Département de Santé Environnementale et Santé au Travail, École de Santé Publique de l'Université de Montréal (ESPUM), Montréal, QC H3C 3J7, Canada.
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Srivastava P, Sreekrishnan TR, Nema AK. Human health risk assessment and PAHs in a stretch of river Ganges near Kanpur. ENVIRONMENTAL MONITORING AND ASSESSMENT 2017; 189:445. [PMID: 28795279 DOI: 10.1007/s10661-017-6146-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
The presence of 13 polycyclic aromatic hydrocarbons (PAHs) was measured in a small stretch of river Ganges in Kanpur, using high-performance liquid chromatography equipped with photodiode array detector (HPLC/PDA). Non-carcinogenic risk on human health was calculated in the form of hazardous index. Carcinogenic risk was calculated as chronic daily intake and incremental lifetime cancer risk (ILCR) with the help of monitored PAHs in river water. Due to non-availability of reference dose (RfD) values for all the 13 PAHs, the combined hazardous index for three PAHs was calculated. These values in winter, pre-monsoon, and post-monsoon period varied from 6.37 × 10-3 (Bithoor) to 1.12 × 10-2 (Jajmau), 2.89 × 10-3 (Bithoor) to 8.52 × 10-3 (Annandeshwar Temple), and 1.80 × 10-3 (Massacre Ghat) to 6.67 × 10-3 (Jajmau), respectively. In this study, the carcinogenic risk due to PAHs was calculated in the form of ILCR. ILCR due to benzo(a)pyrene (BaP) varied from 1.39 × 10-6 (Massacre Ghat) to 1.45 × 10-5 (Jajmau). ILCR was also calculated with the help of BaPeq for five age groups of people (adults, teenagers, children, toddlers, and infants). The outcome of the study indicates that there is a need to control pollution of the river water to maintain its quality. Continuous discharge of PAHs into the river poses both human health risk and ecological risk.
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Affiliation(s)
- Pooja Srivastava
- Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi, India, Hauz Khas, New Delhi, 110016, India.
| | - T R Sreekrishnan
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - A K Nema
- Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi, India, Hauz Khas, New Delhi, 110016, India
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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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11
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Solga SF. Breath volatile organic compounds for the gut-fatty liver axis: Promise, peril, and path forward. World J Gastroenterol 2014; 20:9017-9025. [PMID: 25083075 PMCID: PMC4112861 DOI: 10.3748/wjg.v20.i27.9017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/15/2014] [Accepted: 04/09/2014] [Indexed: 02/06/2023] Open
Abstract
The worldwide interest in the gut microbiome and its impact on the upstream liver highlight a critical upside to breath research: it can uniquely measure otherwise unmeasurable biology. Bacteria make gases [volatile organic compounds (VOCs)] that are directly relevant to pathophysiology of the fatty liver and associated conditions, including obesity. Measurement of these VOCs and their metabolites in the exhaled breath, therefore, present an opportunity to safely and easily evaluate, on both a personal and a population level, some of our most pressing public health threats. This is an opportunity that must be pursued. To date, however, breath analysis remains a slowly evolving field which only occasionally impacts clinical research or patient care. One major obstacle to progress is that breath analysis is inherently and emphatically mutli-disciplinary: it connects engineering, chemistry, breath mechanics, biology and medicine. Unbalanced or incomplete teams may produce inconsistent and often unsatisfactory results. A second impediment is the lack of a well-known stepwise structure for the development of non-invasive diagnostics. As a result, the breath research landscape is replete with orphaned single-center pilot studies. Often, important hypotheses and key observations have not been pursued to maturation. This paper reviews the rationale and requirements for breath VOC research applied to the gut-fatty liver axis and offers some suggestions for future development.
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12
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Aylward LL, Kirman CR, Schoeny R, Portier CJ, Hays SM. Evaluation of biomonitoring data from the CDC National Exposure Report in a risk assessment context: perspectives across chemicals. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:287-94. [PMID: 23232556 PMCID: PMC3621178 DOI: 10.1289/ehp.1205740] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 12/04/2012] [Indexed: 05/19/2023]
Abstract
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.
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Affiliation(s)
- Lesa L Aylward
- Summit Toxicology LLP, Falls Church, Virginia 22044, USA.
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Assessing the impact of child/adult differences in hepatic first-pass effect on the human kinetic adjustment factor for ingested toxicants. Regul Toxicol Pharmacol 2012. [PMID: 23200794 DOI: 10.1016/j.yrtph.2012.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The objective of this study was to evaluate the impact of interindividual differences in hepatic first-pass effect (FPE) on the magnitude of the human kinetic adjustment factor (HKAF) for ingested toxicants. This factor aims at replacing a default value of 3.2 used in non-cancer risk assessment. Coupled with Monte Carlo simulations, steady-state equations that account for FPE were used to obtain distributions of arterial blood concentrations (CAss) and rates of metabolism in adults, neonates, infants and toddlers continuously exposed to an oral dose of 1 μg/kg/d of theoretical CYP2E1 and CYP1A2 substrates. For such substrates exhibiting a range of blood:air partition coefficients (Pb: 1-10,000) and hepatic extraction ratios in an average adult (E(ad): 0.01-0.99), HKAFs were computed as the ratio of the 95th percentile of dose metrics for each subpopulation over the 50th percentile value in adults. The reduced hepatic enzyme content in neonates as compared to adults resulted in correspondingly diminished FPE. Consequently, HKAFs greater than 3.2 could be observed, based on CAss only, in the following cases: for some CYP2E1 substrates with E(ad) ≤ 0.3, in neonates (max.: 6.3); and for some CYP1A2 substrates with E(ad) ≤ 0.1 and 0.7, in, respectively, neonates and infants (max.: 28.3). Overall, this study pointed out the importance of accounting for child/adult differences in FPE when determining the HKAF for oral exposure.
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Mumtaz M, Fisher J, Blount B, Ruiz P. Application of physiologically based pharmacokinetic models in chemical risk assessment. J Toxicol 2012; 2012:904603. [PMID: 22523493 PMCID: PMC3317240 DOI: 10.1155/2012/904603] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 12/21/2011] [Indexed: 12/21/2022] Open
Abstract
Post-exposure risk assessment of chemical and environmental stressors is a public health challenge. Linking exposure to health outcomes is a 4-step process: exposure assessment, hazard identification, dose response assessment, and risk characterization. This process is increasingly adopting "in silico" tools such as physiologically based pharmacokinetic (PBPK) models to fine-tune exposure assessments and determine internal doses in target organs/tissues. Many excellent PBPK models have been developed. But most, because of their scientific sophistication, have found limited field application-health assessors rarely use them. Over the years, government agencies, stakeholders/partners, and the scientific community have attempted to use these models or their underlying principles in combination with other practical procedures. During the past two decades, through cooperative agreements and contracts at several research and higher education institutions, ATSDR funded translational research has encouraged the use of various types of models. Such collaborative efforts have led to the development and use of transparent and user-friendly models. The "human PBPK model toolkit" is one such project. While not necessarily state of the art, this toolkit is sufficiently accurate for screening purposes. Highlighted in this paper are some selected examples of environmental and occupational exposure assessments of chemicals and their mixtures.
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Affiliation(s)
- Moiz Mumtaz
- Computational Toxicology and Methods Development Laboratory, Division of Toxicology and Environmental Medicine (DTEM), Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, GA 30333, USA
| | - Jeffrey Fisher
- National Center for Toxicological Research, USFDA, Jefferson, AR 72079, USA
| | - Benjamin Blount
- Division of Laboratory Studies, National Center for Environmental Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30341, USA
| | - Patricia Ruiz
- Computational Toxicology and Methods Development Laboratory, Division of Toxicology and Environmental Medicine (DTEM), Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, GA 30333, USA
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Becker RA, Hays SM, Robison S, Aylward LL. Development of screening tools for the interpretation of chemical biomonitoring data. J Toxicol 2012; 2012:941082. [PMID: 22518117 PMCID: PMC3306934 DOI: 10.1155/2012/941082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 12/05/2011] [Indexed: 01/27/2023] Open
Abstract
Evaluation of a larger number of chemicals in commerce from the perspective of potential human health risk has become a focus of attention in North America and Europe. Screening-level chemical risk assessment evaluations consider both exposure and hazard. Exposures are increasingly being evaluated through biomonitoring studies in humans. Interpreting human biomonitoring results requires comparison to toxicity guidance values. However, conventional chemical-specific risk assessments result in identification of toxicity-based exposure guidance values such as tolerable daily intakes (TDIs) as applied doses that cannot directly be used to evaluate exposure information provided by biomonitoring data in a health risk context. This paper describes a variety of approaches for development of screening-level exposure guidance values with translation from an external dose to a biomarker concentration framework for interpreting biomonitoring data in a risk context. Applications of tools and concepts including biomonitoring equivalents (BEs), the threshold of toxicologic concern (TTC), and generic toxicokinetic and physiologically based toxicokinetic models are described. These approaches employ varying levels of existing chemical-specific data, chemical class-specific assessments, and generic modeling tools in response to varying levels of available data in order to allow assessment and prioritization of chemical exposures for refined assessment in a risk management context.
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Affiliation(s)
- Richard A. Becker
- Regulatory and Technical Affairs Department, American Chemistry Council, Washington, DC 20002, USA
| | | | - Steven Robison
- Central Product Safety, Procter & Gamble, Cincinnati, OH 45253, USA
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Hays SM, Pyatt DW, Kirman CR, Aylward LL. Biomonitoring Equivalents for benzene. Regul Toxicol Pharmacol 2012; 62:62-73. [DOI: 10.1016/j.yrtph.2011.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 12/02/2011] [Accepted: 12/02/2011] [Indexed: 10/14/2022]
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Boogaard PJ, Aylward LL, Hays SM. Application of human biomonitoring (HBM) of chemical exposure in the characterisation of health risks under REACH. Int J Hyg Environ Health 2012; 215:238-41. [DOI: 10.1016/j.ijheh.2011.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 04/29/2011] [Accepted: 09/05/2011] [Indexed: 12/01/2022]
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Kirman CR, Aylward LL, Blount BC, Pyatt DW, Hays SM. Evaluation of NHANES biomonitoring data for volatile organic chemicals in blood: application of chemical-specific screening criteria. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2012; 22:24-34. [PMID: 21989501 DOI: 10.1038/jes.2011.37] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 08/01/2011] [Indexed: 05/31/2023]
Abstract
Available biomonitoring data for volatile organic chemicals (VOCs) in blood from the National Health and Nutrition Examination Survey (NHANES) (2003-2004) (CDC, 2009) were compared with recently derived screening biomonitoring equivalent (BE) values (Aylward et al., 2010). A BE is defined as the estimated concentration or range of concentrations of a chemical or its metabolites in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guidance value. Blood concentrations of VOCs from the NHANES data set were compared with predicted screening BE values based upon a hazard quotient (HQ) for individual chemicals, and a hazard index (HI) approach for combined exposures. HI values for detected chemicals were generally at or below a value of 1, suggesting that the potential for deleterious effects is low. However, smoking was an important determinant of HI and HQ values. Detected levels of benzene in non-smokers were within the range of BE values corresponding to a 1 × 10(-6)-1 × 10(-4) range for upper-bound cancer risk; in smokers, levels of benzene were at the upper end of or exceeded this range. For VOCs that were not detected in the NHANES sampling, analytical detection limits were generally sufficiently sensitive to detect concentrations consistent with existing non-cancer and cancer risk-based exposure guidance values. Interpretations of measured blood concentrations of VOCs must be made with caution due to the substantial within-individual, within-day fluctuations in levels expected due to the rapid elimination of VOCs.
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Wu B, Zhang Y, Zhang XX, Cheng SP. Health risk assessment of polycyclic aromatic hydrocarbons in the source water and drinking water of China: Quantitative analysis based on published monitoring data. THE SCIENCE OF THE TOTAL ENVIRONMENT 2011; 410-411:112-118. [PMID: 21995876 DOI: 10.1016/j.scitotenv.2011.09.046] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 09/11/2011] [Accepted: 09/16/2011] [Indexed: 05/31/2023]
Abstract
A carcinogenic risk assessment of polycyclic aromatic hydrocarbons (PAHs) in source water and drinking water of China was conducted using probabilistic techniques from a national perspective. The published monitoring data of PAHs were gathered and converted into BaP equivalent (BaP(eq)) concentrations. Based on the transformed data, comprehensive risk assessment was performed by considering different age groups and exposure pathways. Monte Carlo simulation and sensitivity analysis were applied to quantify uncertainties of risk estimation. The risk analysis indicated that, the risk values for children and teens were lower than the accepted value (1.00E-05), indicating no significant carcinogenic risk. The probability of risk values above 1.00E-05 was 5.8% and 6.7% for adults and lifetime groups, respectively. Overall, carcinogenic risks of PAHs in source water and drinking water of China were mostly accepted. However, specific regions, such as Yellow river of Lanzhou reach and Qiantang river should be paid more attention. Notwithstanding the uncertainties inherent in the risk assessment, this study is the first attempt to provide information on carcinogenic risk of PAHs in source water and drinking water of China, and might be useful for potential strategies of carcinogenic risk management and reduction.
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Affiliation(s)
- Bing Wu
- State key lab of pollutant control and resource reuse, School of the Environment, Nanjing University, Nanjing, PR China.
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Angerer J, Aylward LL, Hays SM, Heinzow B, Wilhelm M. Human biomonitoring assessment values: Approaches and data requirements. Int J Hyg Environ Health 2011; 214:348-60. [DOI: 10.1016/j.ijheh.2011.06.002] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/06/2011] [Accepted: 06/08/2011] [Indexed: 01/29/2023]
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Human biomonitoring as a pragmatic tool to support health risk management of chemicals – Examples under the EU REACH programme. Regul Toxicol Pharmacol 2011; 59:125-32. [DOI: 10.1016/j.yrtph.2010.09.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 09/25/2010] [Accepted: 09/27/2010] [Indexed: 11/18/2022]
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