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Hui H, Zang S. Distribution and ecological risk assessment of organochlorine pesticides in sediments from four lakes of Heilongjiang Province, China. ECOTOXICOLOGY (LONDON, ENGLAND) 2014; 23:601-608. [PMID: 24420623 DOI: 10.1007/s10646-014-1184-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
There is growing concern for the lake environment because polluted sediments may cause ecotoxicological effects. In the current study, persistent organochlorine compounds (OCPs), including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and cyclodienes, were analyzed in core sediments taken from Huoshaohei Lake, Xihulu Lake, Wanghua Lake and Keqin Lake, Heilongjiang Province, China. The total OCPs concentrations ranged from 0.92 to 7.09, 0.15 to 9.95, 0.19 to 1.84 and 0.06 to 3.52 ng/g, respectively. The most dominant pollutants were the HCHs, high proportions of γ-HCH isomer indicating the recent input of lindane. The ratios of α-HCH/γ-HCH of four lakes are all lower than that in technical HCH mixtures indicating that there was input of lindane in the past several years, and the mean ratios of (DDE+DDD)/DDTs are all <0.5, suggesting recent release of DDT compounds. Compared with the corresponding ecological environmental quality guidelines from Ingersoll and base on the model of risk based corrective action environmental health risk assessment, the sediments from the four lakes poses a lower potential hazard to human health and the environment but still should be taken into account.
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Affiliation(s)
- Hongkuan Hui
- Key Laboratory of Remote Sensing Monitoring of Geographic Environment, College of Heilongjiang Province, Harbin Normal University, No. 1 South Shida Road, Limin Economic Development Zone, Harbin, 150025, Heilongjiang, People's Republic of China
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Guyton KZ, Barone S, Brown RC, Euling SY, Jinot J, Makris S. Mode of action frameworks: a critical analysis. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2008; 11:16-31. [PMID: 18176885 DOI: 10.1080/10937400701600321] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Mode of action (MOA) information is increasingly being applied in human health risk assessment. The MOA can inform issues such as the relevance of observed effects in laboratory animals to humans, and the variability of response within the human population. Several collaborative groups have developed frameworks for analyzing and utilizing MOA information in human health risk assessment of environmental carcinogens and toxins, including the International Programme on Chemical Safety, International Life Sciences Institute, and U.S. Environmental Protection Agency. With the goal of identifying gaps and opportunities for progress, we critically evaluate several of these MOA frameworks. Despite continued improvement in incorporating biological data in human health risk assessment, several notable challenges remain. These include articulation of the significant role of scientific judgment in establishing an MOA and its relevance to humans. In addition, binary (yes/no) decisions can inappropriately exclude consideration of data that may nonetheless be informative to the overall assessment of risk. Indeed, the frameworks lack a broad consideration of known causes of human disease and the potential for chemical effects to act additively with these as well as endogenous background processes. No integrated analysis of the impact of multiple MOAs over the same dose range, or of varying MOAs at different life stages, is included. Separate consideration of each MOA and outcome limits understanding of how multiple metabolites, modes, and toxicity pathways contribute to the toxicological profile of the chemical. An extension of the analyses across outcomes with common modes is also needed.
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Affiliation(s)
- Kathryn Z Guyton
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA.
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Pearson JT, Wahlstrom JL, Dickmann LJ, Kumar S, Halpert JR, Wienkers LC, Foti RS, Rock DA. Differential Time-Dependent Inactivation of P450 3A4 and P450 3A5 by Raloxifene: A Key Role for C239 in Quenching Reactive Intermediates. Chem Res Toxicol 2007; 20:1778-86. [DOI: 10.1021/tx700207u] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Josh T. Pearson
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Jan L. Wahlstrom
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Leslie J. Dickmann
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Santosh Kumar
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - James R. Halpert
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Larry C. Wienkers
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Robert S. Foti
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
| | - Dan A. Rock
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1201 Amgen Court West, Seattle, Washington 98119-3105, and Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-1031
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Abstract
The aim of the current review is to summarise the present status of physiologically based pharmacokinetic (PBPK) modelling and its applications in drug research, and thus serve as a reference point to people interested in the methodology. The review is structured into three major sections. The first discusses the existing methodologies and techniques of PBPK model development. The second describes some of the most interesting PBPK model implementations published. The final section is devoted to a discussion of the current limitations and the possible future developments of the PBPK modelling approach. The current review is focused on papers dealing with the pharmacokinetics and/or toxicokinetics of medicinal compounds; references discussing PBPK models of environmental compounds are mentioned only if they represent considerable methodological developments or reveal interesting interpretations and/or applications.The major conclusion of the review is that, despite its significant potential, PBPK modelling has not seen the development and implementation it deserves, especially in the drug discovery, research and development processes. The main reason for this is that the successful development and implementation of a PBPK model is seen to require the investment of significant experience, effort, time and resources. Yet, a substantial body of PBPK-related research has been accumulated that can facilitate the PBPK modelling and implementation process. What is probably lagging behind is the expertise component, where the demand for appropriately qualified staff far outreaches availability.
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Affiliation(s)
- Ivan Nestorov
- Pharmacokinetics and Drug Metabolism, Amgen Inc., 30-O-B, One Amgen Center Drive, Thousand Oaks, CA 91320-1789, USA.
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Edler L, Poirier K, Dourson M, Kleiner J, Mileson B, Nordmann H, Renwick A, Slob W, Walton K, Würtzen G. Mathematical modelling and quantitative methods. Food Chem Toxicol 2002; 40:283-326. [PMID: 11893400 DOI: 10.1016/s0278-6915(01)00116-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present review reports on the mathematical methods and statistical techniques presently available for hazard characterisation. The state of the art of mathematical modelling and quantitative methods used currently for regulatory decision-making in Europe and additional potential methods for risk assessment of chemicals in food and diet are described. Existing practices of JECFA, FDA, EPA, etc., are examined for their similarities and differences. A framework is established for the development of new and improved quantitative methodologies. Areas for refinement, improvement and increase of efficiency of each method are identified in a gap analysis. Based on this critical evaluation, needs for future research are defined. It is concluded from our work that mathematical modelling of the dose-response relationship would improve the risk assessment process. An adequate characterisation of the dose-response relationship by mathematical modelling clearly requires the use of a sufficient number of dose groups to achieve a range of different response levels. This need not necessarily lead to an increase in the total number of animals in the study if an appropriate design is used. Chemical-specific data relating to the mode or mechanism of action and/or the toxicokinetics of the chemical should be used for dose-response characterisation whenever possible. It is concluded that a single method of hazard characterisation would not be suitable for all kinds of risk assessments, and that a range of different approaches is necessary so that the method used is the most appropriate for the data available and for the risk characterisation issue. Future refinements to dose-response characterisation should incorporate more clearly the extent of uncertainty and variability in the resulting output.
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Affiliation(s)
- L Edler
- Deutsches Krebsforschungszentrum, German Cancer Research Center, Abteilung Biostatistik R 0700, Postfach 10 19 49, D-69009, Heidelberg, Germany
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Abstract
Quantitative estimation of health risks depends on exposure characterization, the nature of the dose response relationships, and the toxicity of the agents involved. The greatest uncertainties in risk assessment almost always arise from sparse or inadequate exposure data, inadequate understanding of exposure mechanisms, and insufficient understanding of the exposure-dose-response pathway. Additional sources of uncertainty arise when mixed or multiple exposures are implicated in the disease pathway, and as a result of variability in both exposures and responses within and between individuals. Here we consider the role of exposure assessment in the risk assessment process, the use of biological markers or molecular epidemiology to contribute to improvements in exposure assessment for risk assessment, and uncertainties associated with the use of biological markers.
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Affiliation(s)
- P A Schulte
- National Institute for Occupational Safety and Health (NIOSH), Education and Information Division, Robert A. Taft Laboratories, Cincinnati, Ohio 45226, USA. pas4@cdc/gov
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