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Jabłońska-Trypuć A. A review on triclosan in wastewater: Mechanism of action, resistance phenomenon, environmental risks, and sustainable removal techniques. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2023; 95:e10920. [PMID: 37610032 DOI: 10.1002/wer.10920] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/16/2023] [Accepted: 08/20/2023] [Indexed: 08/24/2023]
Abstract
Triclosan, belonging to the bisphenols, is a known antiseptic broad-spectrum biocide. It has a very wide range of applications, both in health care and in the household. Triclosan enters the environment, both water bodies and soil, because of its high prevalence and the ability to accumulation. Excessive use of antimicrobial formulations may cause the generation of resistance among microorganisms. Reduced susceptibility to triclosan is observed more frequently and in an expanded group of microorganisms and is conditioned by a number of different mechanisms occurring on the molecular level. Conventional wastewater treatment processes are not always able to provide a reliable barrier to triclosan. Therefore, additional advanced treatment technologies are being considered in areas, where a triclosan contamination problem has been identified. Removal of triclosan from wastewater is carried out using different biological and chemical techniques; however, it should be pointed out that physico-chemical methods often generate toxic by-products. Toxicity of triclosan and its degradation products, bacterial resistance to this compound, and evident problems with triclosan elimination from wastewater are currently the main problems faced by companies creating products containing triclosan. PRACTITIONER POINTS: Triclosan is an emerging pollutant in the environment because of its ability to accumulation and high prevalence. Reduced susceptibility to triclosan is being observed more frequently. Conventional wastewater treatment processes are not always able to provide a reliable barrier to triclosan. Additional advanced treatment technologies should be implemented to remove triclosan from wastewater.
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Affiliation(s)
- Agata Jabłońska-Trypuć
- Department of Chemistry, Biology and Biotechnology, Faculty of Civil Engineering and Environmental Sciences, Bialystok University of Technology, Białystok, Poland
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Lee S, Lim Y, Kang Y, Jung K, Jee S. The Association between Blood Concentrations of PCDD/DFs, DL-PCBs and the Risk of Type 2 Diabetes Mellitus and Thyroid Cancer in South Korea. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19148745. [PMID: 35886598 PMCID: PMC9320419 DOI: 10.3390/ijerph19148745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/06/2022] [Accepted: 07/14/2022] [Indexed: 02/06/2023]
Abstract
Background and Objectives: Epidemiological studies have inconsistently shown an association between dioxin and risk of type 2 diabetes mellitus (T2DM) and cancer. This study aims to examine the effects of blood concentration of dioxin-like polychlorinated biphenyls (DL-PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) on T2DM and thyroid cancer. Methods: We conducted a nested case–control study within the Korean cancer prevention study-II (KCPS-II) consisting of 15 thyroid cancer cases, 30 T2DM cases, and 55 controls. A total of 500 samples were used in 100 pooling samples. An average value of a pooled sample was calculated weighted by the blood volume of each sample. Results: The study population included 100 participants from the KCPS-II (median (IQR) baseline age, 54.06 [21.04] years; 48 women). The toxic equivalents of PCDD/DFs showed a significant positive association with T2DM and thyroid cancer, after adjustments for potential confounders (T2DM ORs = 1.23; 95% CI = 1.05–1.43; thyroid cancer ORs = 1.34; 95% CI = 1.12–1.61). Conclusion: In this study, both T2DM and thyroid cancer were associated with the blood concentrations of PCDD/DFs. The association between PCDD/DFs and T2D was found among women but not among men. Our findings suggest that further biochemical in vivo research and epidemiologic studies are needed to clarify the association between dioxins concentrations and diseases.
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Affiliation(s)
- SuHyun Lee
- Department of Epidemiology and Health Promotion, Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul 03722, Korea; (S.L.); (S.J.)
- Department of Public Health, Graduate School, Yonsei University, Seoul 03722, Korea
| | - YoungWook Lim
- Institute for Environmental Research, Yonsei University College of Medicine, Seoul 03722, Korea;
| | - YounSeok Kang
- Environment Testing Division, Eurofins Korea Ltd., Gunpo 15849, Korea;
| | - KeumJi Jung
- Department of Epidemiology and Health Promotion, Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul 03722, Korea; (S.L.); (S.J.)
- Correspondence:
| | - SunHa Jee
- Department of Epidemiology and Health Promotion, Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul 03722, Korea; (S.L.); (S.J.)
- Department of Public Health, Graduate School, Yonsei University, Seoul 03722, Korea
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Hryhorczuk D, Dardynskaia I, Hirt C, Dardynskiy O, Turner W, Ruestow P, Bartell S, Steenland K, Zvinchuk O, Baccarelli AA. t(14;18) Translocations in Dioxin-Exposed Workers. J Occup Environ Med 2022; 64:331-339. [PMID: 34740219 DOI: 10.1097/jom.0000000000002427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine if occupational exposure to dioxins is associated with an increased frequency of t(14;18) translocations. METHODS A cross-sectional analysis of serum dioxin levels and t(14;18) frequencies in peripheral blood mononuclear cells in 218 former chemical plant workers and 150 population controls. RESULTS The workers had significantly higher geometric mean serum levels of 2,3,7,8-TCDD (26.2 vs 2.5 ppt) and TEQ (73.8 vs 17.7 ppt) than controls. There were no significant differences in the prevalence or frequency of t(14;18) translocations in the workers compared to controls. Among former workers with current or past chloracne who were t(14;18) positive, the frequency of translocations significantly increased with quartiles of 2,3,7,8-TCDD and TEQ. CONCLUSION Chloracne appears to modulate the association between dioxin exposure and increased frequency of t(14;18) translocations.
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Affiliation(s)
- Daniel Hryhorczuk
- Division of Environmental and Occupational Health Sciences, University of Illinois at Chicago School of Public Health, Chicago, Illinois (Dr Hryhorczuk, Dr Dardynskaia); Center for Global Health, University of Illinois College of Medicine, Chicago, Illinois (Dr Hryhorczuk, Dr Dardynskiy); Department of Internal Medicine C, Hematology and Oncology, Greifswald University, Greifswald, Germany (Dr Hirt); Environmental and Earth Sciences, Exponent, Atlanta, Georgia (Mr Turner); City of Chicago Department of Public Health, Chicago, Illinois (Dr Ruestow); Program in Public Health, University of California at Irvine, Irvine, California (Dr Bartell); Rollins School of Public Health, Emory University, Atlanta, Georgia (Dr Steenland); Institute of Pediatrics, Obstetrics and Gynecology, Kyiv, Ukraine (Dr Zvinchuk); Columbia University Mailman School of Public Health, New York, New York (Dr Baccarelli)
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Shallis RM, Gore SD. Agent Orange and dioxin-induced myeloid leukemia: a weaponized vehicle of leukemogenesis. Leuk Lymphoma 2022; 63:1534-1543. [PMID: 35105250 DOI: 10.1080/10428194.2022.2034156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Agent Orange (AO) was the dominant weaponized herbicide employed by the United States (US) military during the Vietnam war. AO, however, was found to be regularly contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic dioxin known; furthermore, AO was commonly diluted in the field with other aromatic hydrocarbons to assist with delivery mechanisms. Unbeknownst to the US military and the millions exposed, these events have likely contributed to the development of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) that has affected many veterans. Null studies regarding an association between AO exposure and AML/MDS are limited in their methodology and application. The acknowledgement that the known carcinogen TCDD was a contaminant in AO when paired with a strong biological plausibility for its leukemogenicity and an observed increased risk of AML/MDS in TCDD-exposed individuals should suffice to establish causal association and that veterans to whom this might apply should be awarded appropriate indemnity.
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Affiliation(s)
- Rory M Shallis
- Section of Hematology, Department of Internal Medicine, Yale University School of Medicine and Yale Cancer Center, New Haven, CT, USA
| | - Steven D Gore
- Section of Hematology, Department of Internal Medicine, Yale University School of Medicine and Yale Cancer Center, New Haven, CT, USA
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Shallis RM, Weiss JJ, Deziel NC, Gore SD. Challenging the concept of de novo acute myeloid leukemia: Environmental and occupational leukemogens hiding in our midst. Blood Rev 2020; 47:100760. [PMID: 32988660 DOI: 10.1016/j.blre.2020.100760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/28/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022]
Abstract
Myeloid neoplasms like acute myeloid leukemia (AML) originate from genomic disruption, usually in a multi-step fashion. Hematopoietic stem/progenitor cell acquisition of abnormalities in vital cellular processes, when coupled with intrinsic factors such as germline predisposition or extrinsic factors such as the marrow microenvironment or environmental agents, can lead to requisite pre-leukemic clonal selection, expansion and evolution. Several of these entities have been invoked as "leukemogens." The known leukemogens are numerous and are found in the therapeutic, occupational and ambient environments, however they are often difficult to implicate for individual patients. Patients treated with particular chemotherapeutic agents or radiotherapy accept a calculated risk of therapy-related AML. Occupational exposures to benzene, dioxins, formaldehyde, electromagnetic and particle radiation have been associated with an increased risk of AML. Although regulatory agencies have established acceptable exposure limits in the workplace, accidental exposures and even ambient exposures to leukemogens are possible. It is plausible that inescapable exposure to non-anthropogenic ambient leukemogens may be responsible for many cases of non-inherited de novo AML. In this review, we discuss the current understanding of leukemogens as they relate to AML, assess to what extent the term "de novo" leukemia is meaningful, and describe the potential to identify and characterize new leukemogens.
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Affiliation(s)
- Rory M Shallis
- Section of Hematology, Department of Medicine, Yale University School of Medicine, New Haven, USA.
| | - Julian J Weiss
- Section of Hematology, Department of Medicine, Yale University School of Medicine, New Haven, USA
| | - Nicole C Deziel
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Steven D Gore
- Section of Hematology, Department of Medicine, Yale University School of Medicine, New Haven, USA
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Xu J, Ye Y, Huang F, Chen H, Wu H, Huang J, Hu J, Xia D, Wu Y. Association between dioxin and cancer incidence and mortality: a meta-analysis. Sci Rep 2016; 6:38012. [PMID: 27897234 PMCID: PMC5126552 DOI: 10.1038/srep38012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 11/03/2016] [Indexed: 01/11/2023] Open
Abstract
The objective of the present study was to systematically assess the association between dioxin/2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and cancer incidence and mortality. Systematic literature searches were conducted until July 2015 in Pubmed, Embase and Cochrane library to identify relevant studies. A random-effects model was applied to estimate the pooled odds ratio (OR), risk ratio (RR), standard incidence ratio (SIR) or standard mortality ratio (SMR) for cancer incidence or mortality. In addition, dose-response, meta-regression, subgroup, and publication bias analyses were conducted. Thirty-one studies involving 29,605 cancer cases and 3,478,748 participants were included. Higher external exposure level of TCDD was significantly associated with all cancer mortality (pooled SMR = 1.09, 95% CI: 1.01-1.19, p = 0.04), but not all cancer incidence (pooled RR = 1.01, 95% CI: 0.97-1.06, p = 0.49). Higher blood level of TCDD was both significantly associated with all cancer incidence (pooled RR = 1.57, 95% CI: 1.21-2.04, p = 0.001) and all cancer mortality (pooled SMR = 1.45, 95% CI: 1.25-1.69, p < 0.001). Subgroup analysis suggested that higher external exposure and blood level of TCDD were both significantly associated with the mortality caused by non-Hodgkin's lymphoma. In conclusion, external exposure and blood level of TCDD were both significantly associated with all cancer mortality, especially for non-Hodgkin's lymphoma.
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Affiliation(s)
- Jinming Xu
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Yao Ye
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Fang Huang
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Hanwen Chen
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Han Wu
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jian Huang
- Department of Oncology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jian Hu
- Department of Thoracic Surgery, The first Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Dajing Xia
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Yihua Wu
- Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, 310058, China
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Regulations and Advisories. Toxicol Ind Health 2016. [DOI: 10.1177/074823370001600312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Dong Z, Yuan G, Hu J. Uncertainty analysis in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) cancer dose-response for three occupational cohorts. ENVIRONMENT INTERNATIONAL 2016; 88:53-59. [PMID: 26708281 DOI: 10.1016/j.envint.2015.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/19/2015] [Accepted: 12/10/2015] [Indexed: 06/05/2023]
Abstract
While the U.S. EPA has issued a draft report with a 1% TCDD effective dose (ED01) of 87.9pg/kg/day based on continuous integration of key scientific evidence, a detailed and comprehensive uncertainty analysis has not been well documented. In this study, a new estimate for ED01 was derived based on uncertainty analysis by quantitatively assessing the potential bias arising from the selection of kinetic models, dose-response models and cohorts. The cumulative serum lipid concentration (CSLC) and cumulative body burden (CBB) were reconstructed as dose metrics using a concentration- and age-dependent pharmacokinetic model (CADM), physiologically based pharmacokinetic model (PBPK), and age-dependent half-life model (FV), and the reconstructed dose metrics based on CADM and PBPK were generally higher than those based on the FV model. Three dose-response curves (linear, multiplicative and power) were used to link dose metrics and cancer risk to estimate ED01, and the linear model resulted in the lowest ED01, followed by the power model and multiplicative model, for the same cohort. Meanwhile, ED01 based on the CADM model was the highest, followed by those based on the PBPK model and first-order model. Finally, the ED01 was estimated to be 17.03±7.83pg/kg/day by statistically analyzing the distribution of ED01 values based on various kinetic models, cohorts and dose-response models. The study presented here strengthens the scientific basis for understanding the potential health implications of TCDD exposure.
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Affiliation(s)
- Zhaomin Dong
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Guanxiang Yuan
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Jianying Hu
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
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Patterson AT, Kaffenberger BH, Keller RA, Elston DM. Skin diseases associated with Agent Orange and other organochlorine exposures. J Am Acad Dermatol 2015. [PMID: 26210237 DOI: 10.1016/j.jaad.2015.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organochlorine exposure is an important cause of cutaneous and systemic toxicity. Exposure has been associated with industrial accidents, intentional poisoning, and the use of defoliants, such as Agent Orange in the Vietnam War. Although long-term health effects are systematically reviewed by the Institute of Medicine, skin diseases are not comprehensively assessed. This represents an important practice gap as patients can present with cutaneous findings. This article provides a systematic review of the cutaneous manifestations of known mass organochlorine exposures in military and industrial settings with the goal of providing clinically useful recommendations for dermatologists seeing patients inquiring about organochlorine effects. Patients with a new diagnosis of chloracne, porphyria cutanea tarda, cutaneous lymphomas (non-Hodgkin lymphoma), and soft-tissue sarcomas including dermatofibrosarcoma protuberans and leiomyosarcomas should be screened for a history of Vietnam service or industrial exposure. Inconclusive evidence exists for an increased risk of other skin diseases in Vietnam veterans exposed to Agent Orange including benign fatty tumors, melanomas, nonmelanoma skin cancers, milia, eczema, dyschromias, disturbance of skin sensation, and rashes not otherwise specified. Affected veterans should be informed of the uncertain data in those cases. Referral to Department of Veterans Affairs for disability assessment is indicated for conditions with established associations.
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Affiliation(s)
- Andrew T Patterson
- Division of Dermatology, Ohio State University College of Medicine, Columbus, Ohio; US Air Force, San Antonio Military Medical Center
| | | | - Richard A Keller
- Dermatology, Audie L. Murphy Veterans Hospital, San Antonio, US Air Force, San Antonio, Texas
| | - Dirk M Elston
- Ackerman Academy of Dermatopathology; US Army (Retired)
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Kogevinas M. Epidemiological approaches in the investigation of environmental causes of cancer: the case of dioxins and water disinfection by-products. Environ Health 2011; 10 Suppl 1:S3. [PMID: 21489213 PMCID: PMC3073195 DOI: 10.1186/1476-069x-10-s1-s3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
I will refer in this paper to difficulties in research in environmental causes of cancer using as examples research on dioxins and on drinking water disinfection by-products (DBPs) that have created considerable controversy in the scientific and wider community. Dioxins are highly toxic chemicals that are animal carcinogens. For many years, evaluation of the carcinogenicity of dioxins in humans was based on case-control or registry based studies. The development of methods to measure dioxins in blood indicated that these studies suffered from extreme exposure misclassification. The conduct of large cohort studies of workers with widely contrasted exposures together with the use of biomarkers and models for exposure assessment, led to convincing evidence on the carcinogenicity of dioxins in humans. The high toxicity of a few dioxin congeners, the availability of a scheme to characterize the toxicity of a mixture of dioxins and related compounds and the long half-life of these compounds facilitated epidemiological research. Contrary to dioxins, trihalomethanes (THMs) and most of the hundreds of DBPs in drinking water are chemicals of low toxicity. For more than 15 years, the main evidence on the carcinogenicity of DBPs was through ecological or death certificate studies. More recent studies based on individual assessment confirmed increases in bladder cancer risk. However even those studies ignored the toxicological evidence on the importance of routes of exposure to DBPs other than ingestion and, probably, underestimated the risk. Persistence of weak study designs together with delays in advanced exposure assessment models led to delays in confirming early evidence on the carcinogenicity of DBPs. The evaluation of only a few chemicals when exposure is to a complex mixture remains a major problem in exposure assessment for DBPs. The success of epidemiological studies in identifying increased risks lies primarily on the wide contrast of exposure to DBPs in the general population that overcomes the significant exposure misclassification. Exposure assessment has been the Achilles heel for studies on dioxins and DBPs and cancer. The combination of powerful study designs, advanced exposure assessment together with a better understanding of mechanisms of disease and the use of biomarkers of exposure, led to the strengthening of the epidemiological evidence.
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Affiliation(s)
- Manolis Kogevinas
- Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
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Villeneuve PJ, Steenland K. RE: "Mortality rates among trichlorophenol workers with exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin". Am J Epidemiol 2010; 171:129-30; author reply 130-1. [PMID: 19995829 DOI: 10.1093/aje/kwp380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Benfenati E, Benigni R, Demarini DM, Helma C, Kirkland D, Martin TM, Mazzatorta P, Ouédraogo-Arras G, Richard AM, Schilter B, Schoonen WGEJ, Snyder RD, Yang C. Predictive models for carcinogenicity and mutagenicity: frameworks, state-of-the-art, and perspectives. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2009; 27:57-90. [PMID: 19412856 DOI: 10.1080/10590500902885593] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendous cost (in time, money, animals) of rodent carcinogenicity bioassays. Both mutagenicity and carcinogenicity involve complex, cellular processes that are only partially understood. Advances in technologies and generation of new data will permit a much deeper understanding. In silico methods for predicting mutagenicity and rodent carcinogenicity based on chemical structural features, along with current mutagenicity and carcinogenicity data sets, have performed well for local prediction (i.e., within specific chemical classes), but are less successful for global prediction (i.e., for a broad range of chemicals). The predictivity of in silico methods can be improved by improving the quality of the data base and endpoints used for modelling. In particular, in vitro assays for clastogenicity need to be improved to reduce false positives (relative to rodent carcinogenicity) and to detect compounds that do not interact directly with DNA or have epigenetic activities. New assays emerging to complement or replace some of the standard assays include Vitotox, GreenScreenGC, and RadarScreen. The needs of industry and regulators to assess thousands of compounds necessitate the development of high-throughput assays combined with innovative data-mining and in silico methods. Various initiatives in this regard have begun, including CAESAR, OSIRIS, CHEMOMENTUM, CHEMPREDICT, OpenTox, EPAA, and ToxCast. In silico methods can be used for priority setting, mechanistic studies, and to estimate potency. Ultimately, such efforts should lead to improvements in application of in silico methods for predicting carcinogenicity to assist industry and regulators and to enhance protection of public health.
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Affiliation(s)
- E Benfenati
- Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy.
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Schoonen WGEJ, Westerink WMA, Horbach GJ. High-throughput screening for analysis of in vitro toxicity. EXS 2009; 99:401-52. [PMID: 19157069 DOI: 10.1007/978-3-7643-8336-7_14] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The influence of combinatorial chemistry and high-throughput screening (HTS) technologies in the pharmaceutical industry during the last 10 years has been enormous. However, the attrition rate of drugs in the clinic due to toxicity during this period still remained 40-50%. The need for reduced toxicity failure led to the development of early toxicity screening assays. This chapter describes the state of the art for assays in the area of genotoxicity, cytotoxicity, carcinogenicity, induction of specific enzymes from phase I and II metabolism, competition assays for enzymes of phase I and II metabolism, embryotoxicity as well as endocrine disruption and reprotoxicity. With respect to genotoxicity, the full Ames, Ames II, Vitotox, GreenScreen GC, RadarScreen, and non-genotoxic carcinogenicity assays are discussed. For cytotoxicity, cellular proliferation, calcein uptake, oxygen consumption, mitochondrial activity, radical formation, glutathione depletion as well as apoptosis are described. For high-content screening (HCS), the possibilities for analysis of cytotoxicity, micronuclei, centrosome formation and phospholipidosis are examined. For embryotoxicity, endocrine disruption and reprotoxicity alternative assays are reviewed for fast track analysis by means of nuclear receptors and membrane receptors. Moreover, solutions for analyzing enzyme induction by activation of nuclear receptors, like AhR, CAR, PXR, PPAR, FXR, LXR, TR and RAR are given.
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Pharmacologic profiling of human and rat cytochrome P450 1A1 and 1A2 induction and competition. Arch Toxicol 2008; 82:909-21. [DOI: 10.1007/s00204-008-0317-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 05/06/2008] [Indexed: 01/06/2023]
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Pelclová D, Prázny M, Skrha J, Fenclová Z, Kalousová M, Urban P, Navrátil T, Senholdová Z, Smerhovsky Z. 2,3,7,8-TCDD exposure, endothelial dysfunction and impaired microvascular reactivity. Hum Exp Toxicol 2008; 26:705-13. [PMID: 17984141 DOI: 10.1177/0960327107083971] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular function was examined in subjects with long-term high level of serum 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) during their follow-up visits. Their earlier mean peak TCDD level at the time of exposure in 1965-1968 was estimated in the range of 3300-74 000 pg/g lipids. Ten former pesticide production workers heavily exposed to TCDD (age 57 +/- 2 years, TCDD about 170 pg/g lipids) were examined in 2001. Extended group of 15 TCDD-exposed men (age 59 +/- 3 years, TCDD about 130 pg/g lipids) underwent the same examination in 2004. Findings were compared with a control group of 14 healthy men (age 54 +/- 2 years). Skin microvascular reactivity (MVR) was measured by laser Doppler perfusion monitoring in the forearm during post-occlusive reactive hyperemia (PORH) and thermal hyperemia (TH). Several parameters of MVR in men exposed to TCDD were significantly impaired, compared with the control group and further progression of the impairment of MVR has been observed between years 2001 and 2004. Serum concentration of E-selectin and inhibitor of tissue plasminogen activator 1 (PAI-1) was significantly higher in exposed subjects (56.0 +/- 18.4 ng/mL versus 40.0 +/- 12.0 ng/mL, P = 0.022 and 90.9 +/- 33.3 ng/mL versus 45.0 +/- 18.0, P = 0.002, respectively). In addition, PORH in the forearm was significantly negatively associated with SOD activity (r = -0.77, P = 0.009) as well as the velocity of perfusion increase during TH (r = -0.68, P = 0.03) and TH% (r = -0.78, P = 0.008). Our data document the presence of endothelial dysfunction in TCDD-exposed men.
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Affiliation(s)
- Daniela Pelclová
- Department of Occupational Medicine, 1st Medical Faculty, Charles University and General University Hospital, Na Bojisti 1, Prague, Czech Republic.
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Van Maele-Fabry G, Duhayon S, Mertens C, Lison D. Risk of leukaemia among pesticide manufacturing workers: a review and meta-analysis of cohort studies. ENVIRONMENTAL RESEARCH 2008; 106:121-137. [PMID: 18028905 DOI: 10.1016/j.envres.2007.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 08/30/2007] [Accepted: 09/05/2007] [Indexed: 05/25/2023]
Abstract
PURPOSE The purpose of this paper is to review available cohort studies and to estimate quantitatively the association between occupational exposure in plants manufacturing pesticides and leukaemia. METHODS Following a systematic literature search, relative risks were extracted from 14 studies published between 1984 and 2004. Fixed effect analyses were carried out as heterogeneity between studies was not detected. Meta-analyses were performed on the whole set of data and separate analyses were conducted for specific chemical classes of pesticides as well as type of leukaemia. RESULTS The meta-rate ratio estimate for all studies was 1.43 (95% confidence interval [CI] 1.05-1.94). After stratification by chemical class, consistent increases in the risk of leukaemia were found in all groups but statistical significance was found only for phenoxy herbicides unlikely to have been contaminated with dioxins and furans. This last finding appears equivocal in view of the existing literature. The separate analysis conducted on leukaemias from the myeloid lineage showed the highest relative risk (6.99; 95% CI 1.96-24.90). There was no obvious indication of publication bias. CONCLUSION The overall meta-analysis among pesticide manufacturing workers provides quantitative evidence to consider occupational exposure to pesticides as a possible risk factor for leukaemia but available data are too scarce for causality ascertainment. Epidemiological evidence did not allow identifying a specific pesticide or chemical class that would be responsible for the increased risk. Exposure to pesticides may be a significant risk factor for specifically developing myeloid leukaemia and there is a need for additional large well-conducted studies with clear definition of exposure and of leukaemia type(s).
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Affiliation(s)
- Geneviève Van Maele-Fabry
- Université catholique de Louvain, Industrial Toxicology and Occupational Medicine Unit, Avenue E. Mounier 53, bte 5302, B-1200 Brussels, Belgium.
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Van Maele-Fabry G, Libotte V, Willems J, Lison D. Review and Meta-analysis of Risk Estimates for Prostate Cancer in Pesticide Manufacturing Workers. Cancer Causes Control 2006; 17:353-73. [PMID: 16596288 DOI: 10.1007/s10552-005-0443-y] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 10/31/2005] [Indexed: 12/21/2022]
Abstract
PURPOSE The purpose of the present paper is to review cohort studies that examined the occurrence of prostate cancer in pesticide manufacturing workers in order to undertake a qualitative and quantitative evaluation of the risk as well as to assess the level of epidemiological evidence for each class of chemical compounds. METHODS Following a systematic literature search, relative risk (RR) estimates for prostate cancer were extracted from 18 studies published between 1984 and 2004. All studies were summarised and evaluated for homogeneity and publication bias. As no significant heterogeneity was detected, combined RR estimators were calculated using a fixed effect model. Meta-analyses were performed both on the whole set of data and for each chemical class separately. RESULTS The meta-rate ratio estimate for all studies was 1.28 [95% confidence interval (CI) 1.05-1.58]. After stratification by specific chemical class, consistent increases in the risk of prostate cancer were found in all groups but statistical significance was found only for accidental or non-accidental exposure to phenoxy herbicides contaminated with dioxins and furans. There was no obvious indication of publication bias. CONCLUSION The overall meta-analysis provides additional quantitative evidence consistent with prior reviews focusing on other groups exposed to pesticides (farmers, pesticide applicators). The results again point to occupational exposure to pesticides as a possible risk factor for prostate cancer but the question of causality remains unanswered. Epidemiological evidence did not allow identifying a specific pesticide or chemical class that would be responsible for the increased risk but the strongest evidence comes from workers exposed to phenoxy herbicides possibly in relation with dioxin and/or furan contamination.
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Affiliation(s)
- Geneviève Van Maele-Fabry
- Unité de Toxicologie Industrielle et Médecine du travail, Ecole de Santé Publique, Université Catholique de Louvain, Bruxelles, Belgium.
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Thomae TL, Stevens EA, Bradfield CA. Transforming growth factor-beta3 restores fusion in palatal shelves exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. J Biol Chem 2005; 280:12742-6. [PMID: 15668235 DOI: 10.1074/jbc.m410780200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pollutant, 2,3,7,8-tetrachlorodibenzo-p-dioxin ("dioxin"), has been implicated in the etiology of a wide variety of human birth defects. In an effort to identify pharmacological blockers of dioxin-induced terata, we performed a histological and microscopic analysis of the developing murine palate that had been exposed to dioxin. In both in vivo and in vitro model systems, we observed that dioxin exposure leads to a reduction in the number of filopodial extensions at the medial epithelial edge of the developing palate. Given that this filopodial aberration is similar to the phenotype observed in Tgfbeta3 null mice, a mutant known to display a 100% incidence of cleft palate, we examined the interaction between TGFbeta3 and dioxin in palatal fusion. We found that that the addition of TGFbeta3 to an in vitro palate culture model prevented the dioxin-induced reduction in filopodial density. Moreover, TGFbeta3 exposure completely prevented the dioxin-induced block of palatal fusion in this system. Although these data do not point to a direct cellular or molecular mechanism for TGFbeta3 dioxin antagonism, these results do suggest that TGFbeta3 or stimulators of this signaling pathway hold potential as antidotes for dioxin-induced terata and that this opposing pharmacology may extend to additional toxicological endpoints.
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Affiliation(s)
- Tami L Thomae
- McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA
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Cole P, Trichopoulos D, Pastides H, Starr T, Mandel JS. Dioxin and cancer: a critical review. Regul Toxicol Pharmacol 2004; 38:378-88. [PMID: 14623487 DOI: 10.1016/j.yrtph.2003.08.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
2,3,7,8-tetrachlordibenzo-p-doxin (TCDD) would not have been designated as a Group 1 carcinogen by IARC had there not been a change in the criteria used for inclusion in this category. Furthermore, there is no precedent for indicating, as did IARC, that a single chemical acts as a pluripotential carcinogen by modestly increasing human risk for all cancer while not increasing the risk for any single cancer at least moderately. IARC moved TCDD to Group 1 based on mechanistic considerations focusing on the Ah receptor. However, while occupancy of the Ah receptor by TCDD may be necessary for its toxicity, it is not sufficient for toxicity or for potential carcinogenicity. Animal evidence relating TCDD exposure to cancer is much stronger than that for humans. However, the large inter-species variation in the relevant dose-response slopes severely limits generalizations from animals to humans. The epidemiologic studies of occupational exposures, pesticide applicators, and community exposures following industrial accidents, notably Seveso, have generated overall relative risks of all cancer of about 1.0. Only case-control studies of soft-tissue sarcoma and non-Hodgkin's lymphoma, all by the same investigator, reported elevated risk from TCDD exposure. However, these results have not been replicated. The representation that a chemical compound (TCDD) would be a late-stage carcinogen for all types of cancer has no precedent and lacks biological foundation. Virtually all late-stage or promoting carcinogens (e.g., hepatitis-C virus, asbestos, and estrogens) cause a very limited number of forms of cancer. The exposure-response meta-analysis of TCDD and cancer developed by the United States Environmental Protection Agency (USEPA) is seriously compromised by its failure to adequately fit the data. The studies used by the USEPA also likely underestimate TCDD body burdens and may be confounded by smoking and other occupational exposures. Furthermore, the use of a linear dose-response model by the USEPA is scientifically unjustified since the underlying model of TCDD as a human carcinogen is based primarily on its supposed receptor-mediated, non-genotoxic (or promotional) mode of action. There are few examples of an agent being suspected as a human carcinogen for decades and then eventually moving into the category of "known" human carcinogens. In contrast, there are hundreds of compounds that remain for decades on lists of "suspected" human carcinogens despite the lack of confirming evidence. The long-term accumulation of negative, weak, and inconsistent findings suggests that TCDD eventually will be recognized as not carcinogenic for humans.
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Affiliation(s)
- Philip Cole
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, USA.
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23
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Akhtar FZ, Garabrant DH, Ketchum NS, Michalek JE. Cancer in US Air Force Veterans of the Vietnam War. J Occup Environ Med 2004; 46:123-36. [PMID: 14767215 DOI: 10.1097/01.jom.0000111603.84316.0f] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cancer incidence and mortality were summarized in Air Force veterans of the Vietnam War. The index subjects were Operation Ranch Hand veterans who sprayed 2,3,7,8 tetrachlorodibenzo-p-dioxin (dioxin)-contaminated herbicides in Vietnam. Comparisons served in Southeast Asia during the same period but did not spray herbicides. We assessed cancer incidence and mortality using national rates and contrasted cancer risk in each of three Ranch Hand dioxin exposure categories relative to comparisons. The incidence of melanoma and prostate cancer was increased among white Ranch Hand veterans relative to national rates. Among veterans who spent at most 2 years in Southeast Asia, the risk of cancer at any site, of prostate cancer and of melanoma was increased in the highest dioxin exposure category. These results appear consistent with an association between cancer and dioxin exposure.
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Greene JF, Hays S, Paustenbach D. Basis for a proposed reference dose (RfD) for dioxin of 1-10 pg/kg-day: a weight of evidence evaluation of the human and animal studies. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2003; 6:115-159. [PMID: 12554432 DOI: 10.1080/10937400306470] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The dioxins have been perhaps the most studied of all chemicals to which humans are routinely exposed. It has been reported that more than 5,000 scientific papers have been published that have evaluated the toxicology of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Although the cancer hazard posed by this chemical has probably received the bulk of attention over the past 20 years, the U.S. Environmental Protection Agency (EPA) and the recent U.S. EPA Science Advisory Board (SAB) that reviewed the "Reassessment" have suggested that the noncancer hazard may well be more important than the cancer hazard at current background doses to the general public. The World Health Organization (WHO) and U.K. Food Standards Agency (FAO) committee (JECFA) on dioxins has reached similar conclusions. This article reviews the published studies involving laboratory animals and humans that address the noncancer effects. Based on our review, developmental toxicity is the most sensitive effect of TCDD consistently seen in mice and rats. Specifically, of the various studies, a no-observed-adverse-effects level (NOAEL) of 13 ng/kg (maternal body burden) was identified as the most pertinent for deriving a reference dose (RfD) for humans. Although more than a dozen different adverse effects have been reported in various studies of humans over the past 25 years, the most consistent clinically important adverse effect of human exposure appears to be chloracne. Following a review of all published studies, we concluded that the best estimate of a LOAEL for production of chloracne is approximately 160 ng/kg (body burden). Based on our analysis, an RfD of between 1 and 10 pg/kg-d (TCDD TEQ) is consistent with the objectives of this risk criterion. Maintaining a lifetime average daily dose below this concentration, based on what is known today, should prevent noncancer effects in virtually all persons. This value is consistent with the JECFA recommendation of 70 pg/kg-mo.
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Maruyama W, Yoshida K, Tanaka T, Nakanishi J. Possible range of dioxin concentration in human tissues: simulation with a physiologically based model. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2002; 65:2053-2073. [PMID: 12515586 DOI: 10.1080/00984100290071829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In risk evaluation of dioxins, monitoring chemical concentrations in human tissues is an important step, and these concentration data can be utilized along with animal toxicity data for extrapolation of human manifestation. However large differences in dioxin concentrations usually exist even among individuals who have never been accidentally exposed to high quantities of dioxin, and this may cause problems in risk analysis. Body size, age, and history of food consumption are factors responsible for these interindividual differences in addition to exposure levels. Using a physiologically based pharmacokinetic (PBPK) model, the influence of differences in body weight, gastrointestinal absorption, and half-life and intake of dioxin were examined on tissue chemical concentration. Dioxin concentrations over a 40-yr time course in human liver, kidneys, fat, blood, muscle and richly perfused tissue were simulated for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (CoPCBs). Model parameters such as tissue-blood partition coefficients for CoPCBs were prepared, and sensitivity analysis was also performed on these parameters. The range of tissue concentrations was approximately 0.17 to 4.1 times the standard concentration, which was calculated using standard model parameters. The simulated ranges included more than 80% of the individual anatomical data for 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,2,3,7,-pentachlorodibenzo-p-dioxin, and 3,3',4,4',5-pentachlorobiphenyl in liver, fat, and blood. These results suggest that differences in body weight, gastrointestinal absorption, and food intake behavior may partially explain variation in tissue concentrations among individuals, and the possible interindividual uncertainty, which is approximately 24 for the general Japanese population.
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Affiliation(s)
- Wakae Maruyama
- Graduate School of Environment and Information Sciences, Yokohama National University, Kanagawa, Japan.
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26
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Maruyama W, Yoshida K, Tanaka T, Nakanishi J. Determination of tissue-blood partition coefficients for a physiological model for humans, and estimation of dioxin concentration in tissues. CHEMOSPHERE 2002; 46:975-985. [PMID: 11999780 DOI: 10.1016/s0045-6535(01)00208-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The tissue-blood partition coefficients for a physiologically based pharmacokinetic (PBPK) model were determined, and the concentrations of 17 congeners of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in tissues in Japanese people were estimated using the model. According to the PBPK model established by Lawrence and Gobas [Chemosphere 35 (1997) 427-452], we assumed a steady-state fugacity model for Japanese people in general, and set the route of PCDD/Fs exposure only from food intake. The required partition coefficients for liver, kidney, adipose, muscle, skin, bile, gut and viscera (richly perfused tissue) were calculated using available autopsy data from eight Japanese men and women who were not accidentally exposed to PCDD/Fs. For validation of the partition coefficients, estimated PCDD/F concentrations in liver, kidney, fat, blood and muscle using the model were compared to other two sets of measured concentration data in Japanese tissues. Good agreement was obtained between estimated data and measured data, and most of the measured data were within the simulated concentration range in liver, kidney, blood and muscle. From these results, our model and calculated partition coefficients seem applicable for the estimation of congener-specific concentrations in human tissues.
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Affiliation(s)
- Wakae Maruyama
- Graduate School of Environment and Information Sciences, Yokohama National University, Hodogaya, Kanagawa, Japan.
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27
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Lukinmaa PL, Sahlberg C, Leppäniemi A, Partanen AM, Kovero O, Pohjanvirta R, Tuomisto J, Alaluusua S. Arrest of Rat Molar Tooth Development by Lactational Exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. Toxicol Appl Pharmacol 2001; 173:38-47. [PMID: 11350213 DOI: 10.1006/taap.2001.9155] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interference with tooth development by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was studied in dioxin-resistant Han/Wistar rats. Lactating dams were given a single dose of 50 or 1000 microg TCDD/kg body wt 1 day after delivery and the pup heads were analyzed radiographically or histologically at postnatal days 9 and/or 22. Of 19 animals studied histologically, 10 lacked one or more third molars, which were at the bud stage at the start of the experiment. A higher proportion of pups exposed to the higher dose (9/13) lacked third molars than those exposed to the lower dose (1/6) (27/52 and 2/24 teeth missing, respectively). Missing upper third molars (19/38) were more frequent than were lower (10/38). The development of the third molars present was retarded. The root tips of the more advanced first and second molars were prematurely closed and root formation was arrested, but eruption was not affected. Dentinogenesis of the continuously erupting lower incisor teeth was preeruptively arrested because of pulpal cell death. All the teeth of the control rat pups developed normally. In contrast to the control pups, none of the 11 experimental pups examined radiographically (6 exposed to the higher dose and 5 to the lower) showed mineralization of their third molar cusps. The results show that the effects of TCDD on rat tooth development depend on not only the dose but also the tooth type and developmental stage. Inasmuch as early tooth development is under the control of inductive interactions between the epithelium and the mesenchyme, the interference by TCDD with tooth morphogenesis with the consequent arrest of development is likely to involve epithelial-mesenchymal signaling.
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Affiliation(s)
- P L Lukinmaa
- Department of Oral Pathology, Institute of Dentistry, University of Helsinki, Helsinki, Finland
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28
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Johnson E, Shorter C, Bestervelt L, Patterson D, Needham L, Piper W, Lucier G, Nolan C. Serum hormone levels in humans with low serum concentrations of 2,3,7,8-TCDD. Toxicol Ind Health 2001; 17:105-12. [PMID: 12479506 DOI: 10.1191/0748233701th096oa] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We measured current serum hormone and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations in 37 men who sprayed 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in the State of Victoria, Australia. TCDD levels were consistently significantly inversely related to prolactin levels in all analyses. In correlation analyses, TCDD levels were also inversely related to triiodothyronine (T3), thyroid-stimulating hormone (TSH), and testosterone levels, and positively associated with glucagon levels. The mean serum TCDD concentration in these sprayers was between 2.6 and 8.1 parts per trillion (ppt). Since such TCDD levels are commonly found in the general population in countries such as the US, the results could suggest that background levels of TCDD in the general population could have an effect on hormone levels. The findings are preliminary and need to be replicated in order to evaluate their full public health significance.
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Affiliation(s)
- E Johnson
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1430 Tulane Avenue, New Orleans, Louisiana 70112, USA.
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Affiliation(s)
- M Kogevinas
- Unitat de Recerca Respiratoria i Ambiental. Institut Municipal d'Investigacio Medica (IMIM), Barcelona, Spain.
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30
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Sweeney MH, Mocarelli P. Human health effects after exposure to 2,3,7,8-TCDD. FOOD ADDITIVES AND CONTAMINANTS 2000; 17:303-16. [PMID: 10912244 DOI: 10.1080/026520300283379] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In 1949, the first descriptions of human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)-contaminated chemicals were reported after a trichlorophenol reactor explosion in Nitro, West Virginia, USA. Reported non-cancer health effects included a range of conditions affecting most systems. Additional reports of the health consequences of exposure continued through the remainder of the century. The majority of effects have been reported among highly exposed groups including occupational populations, such as chemical production workers, pesticide applicators, and individuals who handled or were exposed to materials treated with 2,3,7,8-TCDD-contaminated pesticides, and among residents of communities contaminated with tainted waste oil (Missouri, USA) and industrial effluent (Seveso, Italy). For only six exposed populations were biological measurements of 2,3,7,8-TCDD-contaminated collected and used to examine the relationship between non-cancer health effects and exposure. Of the many non-cancer health effects thought to be associated with 2,3,7,8-TCDD exposure, only chloracne, elevations in GGT and triglyceride levels, and alterations in FSH and LH were related to serum 2,3,7,8-TCDD levels. Mortality from cardiovascular diseases also appeared to be elevated among cohorts of exposed chemical workers and Seveso residents. Continued surveillance of the health of exposed populations will be useful in identifying the long-term effects of both high and low 2,3,7,8-TCDD exposure.
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Affiliation(s)
- M H Sweeney
- National Institute for Occupational Safety and Health, Education and Information Division, Cincinatti, OH 45226-1988, USA.
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Abstract
The epidemiological evidence from the most highly 2,3,7,8-TCDD-exposed cohorts studied produces the strongest evidence of increased risks for all cancer combined, along with less strong evidence of increased risks for cancer of particular sites such as non-Hodgkin lymphoma, soft-tissue sarcoma and lung cancer. The relative risk for all cancer combined in the most highly exposed and longer-latency sub-cohorts is 1.4. While this relative risk is not likely to be explained by confounding, this possibility cannot be excluded. It should be borne in mind that the general population is exposed to 2-3 orders of magnitude lower levels of TCDD than those experienced by the equivalent life-time dose in the industrial populations examined or the population of Seveso.
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Affiliation(s)
- M Kogevinas
- Institut Municipal d'Investigaciò Médica (IMIM), Respiratory and Environmental Health Research Unit, Universitat Autonoma de Barcelona, Spain.
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Portier C. Risk ranges for various endpoints following exposure to 2,3,7,8-TCDD. FOOD ADDITIVES AND CONTAMINANTS 2000; 17:335-46. [PMID: 10912247 DOI: 10.1080/026520300283405] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Conducting a dose-response analysis for an environmental contaminant requires a careful evaluation of most of the available data focusing on both the magnitude of the effect and the possible ranges of dose-response shapes which fit the data. This paper calculates potency values (1% response exposures) for human and animal data on cancer, non-cancer and biological effect endpoints for TCDD and finds that a reasonable estimate for 1% excess cancer would be between 1 and 50 pg/kg/day. The paper also evaluates the adequacy of linear and non-linear models for fitting these data and concludes that the assumption of a threshold dose-response is not fully supported by these data.
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Affiliation(s)
- C Portier
- National Institute of Environmental Health Sciences, Laboratory of Computational Biology and Risk Analysis, Research Triangle Park, NC 27709, USA.
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Abstract
Uncertainty in exposure assessment and uncertainty in kinetic models of early effects after exposure to a toxin are addressed in this paper. Sources of uncertainty in the determination of exposure of workers in chemical industry exposed to dioxins are exhibited and a simple kinetic model for biomonitor measurements of the concentrations from occupational exposure is derived. Model uncertainty, and uncertainty in the model parameters of physiologically-based pharmacokinetic models (PBPK models) are addressed when these models are used to estimate the effective dose in risk assessment. Uncertainty in the model parameters originating from the use of different statistical analysis methods is exhibited for Hill type nonlinear kinetics of enzyme induction mediated by a toxin.
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Affiliation(s)
- L Edler
- Biostatistics Unit, German Cancer Research Center, Heidelberg, Germany.
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35
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Sotnichenko AI, Severin SE, Posypanova GA, Feldman NB, Grigor'ev MI, Severin ES, Petrov RV. Water-soluble 2,3,7,8-tetrachlorodibenzo-p-dioxin complex with human alpha-fetoprotein: properties, toxicity in vivo and antitumor activity in vitro. FEBS Lett 1999; 450:49-51. [PMID: 10350055 DOI: 10.1016/s0014-5793(99)00440-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conditions for the formation of a non-covalent complex between 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the human transport fetal protein, alpha-fetoprotein (AFP), have been studied. TCDD has been shown to form a stable complex with AFP in a 2:1 (TCDD:AFP) ratio. The apparent solubility of TCDD in water increases 10(5)-fold after complex formation. The toxicity of the TCDD:AFP complex injected into mice by the intravenous route is comparable with that of free TCDD administered in oil solution per os. The complex manifests very much higher toxicity (200-1400 times) against human tumor cells (CEM, MCF-7, HepG2) in vitro and surpasses TCDD in selectivity. AFP may facilitate TCDD transport in embryonic tissues and enhance its embryotoxic and teratogenic effects.
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Hardell L, Eriksson M, Axelson O. Agent Orange in war medicine: an aftermath myth. INTERNATIONAL JOURNAL OF HEALTH SERVICES 1998; 28:715-24. [PMID: 9842495 DOI: 10.2190/l940-b8fk-3y5e-rg86] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the late 1970s several epidemiological studies have appeared linking exposure to phenoxy herbicides or chlorophenols to some malignant tumors. Most of these compounds are contaminated with dioxins and dibenzofurans; for example, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a contaminant of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a component of Agent Orange which was sprayed in Vietnam during the war. The results of some of the epidemiological studies on cancer risks associated with exposure to these compounds have been manipulated and misinterpreted, particularly by the Australian Royal Commission on the Use and Effects of Chemical Agents on Australian Personnel in Vietnam. Furthermore, a book on Australian war history entitled Medicine at War, commissioned by the Federal Government, reiterates several of these misinterpretations, despite available contrary evaluations from Australian and U.S. authorities. These remarkable and confusing circumstances in the scientific process are considered also in the light of the recent classification of TCDD as carcinogenic to humans, Group 1, by a Working Group at the International Agency for Research on Cancer in Lyon, France.
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Affiliation(s)
- L Hardell
- Department of Oncology, Orebro Medical Centre, Sweden
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Pesatori AC, Zocchetti C, Guercilena S, Consonni D, Turrini D, Bertazzi PA. Dioxin exposure and non-malignant health effects: a mortality study. Occup Environ Med 1998; 55:126-31. [PMID: 9614398 PMCID: PMC1757550 DOI: 10.1136/oem.55.2.126] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To investigate, in a population heavily exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the possible unusual occurrence of diseases other than cancer. METHODS Five year extension of the follow up of the cohort involved in the Seveso accident. Soil measurements identified three exposure zones: (A) highest contamination, (B) substantial, and (R) low but higher than background contamination. Blood TCDD measurements, although limited in number, confirmed zone exposure ranking. The 15 year mortality in the exposed cohort was compared with that of a large population in the surrounding non-contaminated territory. Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated with Poisson regression techniques. RESULTS The already noted increased occurrence of cardiovascular deaths was confirmed, in particular in zone A, among males for chronic ischaemic heart disease (five deaths, RR 3.0, 95% CI 1.2 to 7.3), and among females for hypertensive disease (three deaths, RR 3.6, 95% CI 1.2 to 11.4) and chronic rheumatic heart disease. Novel findings were the increase of chronic obstructive pulmonary disease, most notably among males in zone A (four deaths, RR 3.7, 95% CI 1.4 to 9.9) and females in zone B (seven deaths, RR 2.4, 95% CI 1.1 to 5.1); and from diabetes, which was significantly increased in females in zone B (13 deaths, RR 1.9, 95% CI 1.1 to 3.2). In zone R, chronic ischaemic heart disease (males and females), hypertension (females), and diabetes (females) showed less pronounced, although significant excesses. CONCLUSIONS As well as high TCDD exposure, the accident caused a severe burden of strain in the population. Both these factors might have contributed to the noted increased risks (in particular, circulatory and respiratory). The cardiovascular and immune toxicity of TCDD, as well as its complex interaction with the endocrine system, might be relevant to the explanations of these findings. These results, although not conclusive, concur with previous data in suggesting cardiopulmonary and endocrine effects in humans highly exposed to TCDD.
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Affiliation(s)
- A C Pesatori
- Research Centre for Occupational, Clinical and Environmental Epidemiology (EPOCA), Institute of Occupational Health, University of Milan, Italy
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De Rosa CT, Brown D, Dhara R, Garrett W, Hansen H, Holler J, Jones D, Jordan-Izaguirre D, O'Connor R, Pohl H, Xintaras C. Dioxin and dioxin-like compounds in soil, Part II: Technical support document for ATSDR interim policy guideline. Toxicol Ind Health 1997; 13:769-804. [PMID: 9399422 DOI: 10.1177/074823379701300607] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- C T De Rosa
- Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services Atlanta, Georgia, USA.
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Mahan CM, Bullman TA, Kang HK, Selvin S. A case-control study of lung cancer among Vietnam veterans. J Occup Environ Med 1997; 39:740-7. [PMID: 9273878 DOI: 10.1097/00043764-199708000-00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because of concerns among veterans over Agent Orange exposure, the Department of Veterans Affairs (VA) has conducted a series of studies of specific cancers among Vietnam veterans. Lung cancer is the topic of investigation in this report. The VA's Patient Treatment File (PTF) was used to identify 329 Vietnam era veterans with a diagnosis of lung cancer made between 1983 and 1990. The PTF is a computerized hospitalized database of inpatient records, including patients' demographic data, and diagnoses. A record is created for each patient discharged from any one of the VA's Medical Centers. Variables abstracted from the military record include education, race, branch of service, Military Occupational Specialty Code, rank, and units served within Vietnam. Two hundred sixty-nine controls were randomly selected from the PTF file of men hospitalized for a reason other than cancer. A second control group numbering 111 patients with colon cancer was also selected from the PTF file. Data were also gathered on exposure to Agent Orange through the location of each individual ground troop veteran's unit in relation to an area sprayed and the time elapsed since that area was sprayed. The crude odds ratio between service in Vietnam and lung cancer was of borderline significance (odds ratio = 1.39 with 95% confidence interval = 1.01-1.92). The relationship disappeared when the confounder year of birth was considered. We conclude from these data that there is no evidence of increased risk in lung cancer associated with service in Vietnam at this time.
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Affiliation(s)
- C M Mahan
- Environmental Epidemiology Service, Department of Veterans Affairs, Washington, DC, USA
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Hays SM, Aylward LL, Karch NJ, Paustenbach DJ. The relative susceptibility of animals and humans to the carcinogenic hazard posed by exposure to 2,3,7,8-TCDD: an analysis using standard and internal measures of dose. CHEMOSPHERE 1997; 34:1507-1522. [PMID: 9134683 DOI: 10.1016/s0045-6535(97)00447-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An analysis of the carcinogenic dose-response for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in humans and animals was performed based on measured tissue and serum concentrations and using alternatives to administered dose as the dosimetric. The TCDD-related carcinogenic response in rats (female rat liver tumors from Kociba et al., using revised pathology from Goodman and Sauer, was compared to that in humans (lung cancer rates in Fingerhut et al.,). Three dosimetries were used: serum lipid TCDD area-under-the-curve (AUC), peak serum lipid concentration (Cpeak) and average serum lipid concentration (Cavg). Rat serum concentration-time profiles were estimated based on measured adipose lipid TCDD concentrations at the end of the Kociba et al. bioassay, assuming first-order elimination and a half-life of 25 days. Human concentration-time profiles were estimated based on measured serum lipid TCDD concentrations and known dates of first and last exposure, with an assumed 7.5 year half-life and first-order elimination. Comparison of rat and human responses indicated that, using all three of these dosimetries, humans are much less sensitive than rats to the carcinogenic effects of TCDD. Regardless of the dosimetric chosen, the cancer mortality in humans in the NIOSH cohort, if due to TCDD, is relatively insensitive to dose as defined in Fingerhut et al., [3]. Our analysis indicates that human exposure to background levels of TCDD (about 5 ppt serum lipid concentration) is not likely to produce an incremental cancer risk.
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Affiliation(s)
- S M Hays
- ChemRisk, A Division of McLaren/Hart, Cleveland, OH 44122, USA
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42
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Gibbs LM, Lester SU. The politics of dioxin. New Solut 1996; 7:26-37. [PMID: 22909943 DOI: 10.2190/ns7.1.i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Ott MG, Zober A. Cause specific mortality and cancer incidence among employees exposed to 2,3,7,8-TCDD after a 1953 reactor accident. Occup Environ Med 1996; 53:606-12. [PMID: 8882118 PMCID: PMC1128557 DOI: 10.1136/oem.53.9.606] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the long term health consequences of past occupational exposure to 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). METHODS Cancer incidence and cause specific mortality were examined up to and including 1992 in a group of 243 men with external comparisons and internal dose-response analyses. Model based estimates of TCDD dose (expressed in micrograms/kg body weight) were developed for all cohort members with an approach that incorporated detailed accounts of each employee's work activities, analyses of TCDD in blood lipid of 138 employees, and internally derived estimates of elimination rates of TCDD. RESULTS The estimated dose of TCDD for 135 men was > or = 0.1 microgram/kg body weight and for 69 men > or = 1 microgram/kg body weight. Increased cancer risk ratios were found with higher doses of TCDD and longer interval since first exposure for all sites combined and digestive and respiratory cancers in particular. Within the high dose group (> or = 1 microgram/kg body weight), total cancer mortality was increased > or = 20 years after first exposure (13 cases, standardised mortality ratio (SMR) 1.97, 95% confidence interval (95% CI) 1.05-3.36) as was respiratory cancer (six cases, SMR 3.06; 95% CI 1.12-6.66). Among current cigarette smokers, 12 cancer deaths occurred in the high dose group (SMR 3.42, 95% CI 1.77-5.97) compared with seven deaths at lower doses of TCDD (SMR 1.29, 95% CI 0.52-2.66). Regression analyses based on the Cox's proportional hazards model provided further evidence of a relation between cumulative dose of TCDD and occurrence of both overall and digestive cancer. No evidence of an effect of TCDD on overall mortality or deaths due to circulatory disease was found and no cases of non-Hodgkin's lymphoma or soft tissue sarcoma have been found to date. CONCLUSIONS Our findings are consistent with a carcinogenic effect induced by TCDD at doses > or = 1 microgram/kg body weight. With such a small cohort, the risk estimates are not very stable and could be affected by selection and confounding.
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Affiliation(s)
- M G Ott
- Corporate Medical Department, BASF Corporation, Mount Olive, NJ, USA
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Becher H, Flesch-Janys D, Kauppinen T, Kogevinas M, Steindorf K, Manz A, Wahrendorf J. Cancer mortality in German male workers exposed to phenoxy herbicides and dioxins. Cancer Causes Control 1996; 7:312-21. [PMID: 8734824 DOI: 10.1007/bf00052936] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In an occupational cohort study, the relation between exposure to phenoxy herbicides, and contaminants (dioxins and furans) and cancer mortality was investigated. A total of 2,479 workers from four plants in Germany were included, with a mortality follow-up until the end of 1989 (for one cohort, until the end of 1992). A total of 484 deaths were recorded yielding a standardized mortality ratio (SMR) of 101 (95 percent confidence interval [CI] = 92-111) for total mortality, and an SMR of 119 (CI = 100-141) for all malignant diseases. A variety of herbicides was produced, including those which are known to have been contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). High dioxin and furan exposure (in particular, exposure to TCDD, but also to higher chlorinated dioxins) had occurred in two of the four plants as shown by blood-fat measurements in a sample of workers. Mortality from all neoplasms increased with latency and was highest in the largest plant where the highest TCDD blood levels were recorded. An increased mortality in the total cohort from respiratory cancer (SMR = 154, CI = 115-202), cancer of the buccal cavity and pharynx (SMR = 295, CI = 135-560), and non-Hodgkin's lymphoma (SMR = 326, CI = 119-710) was observed. Our findings are consistent with results from other cohorts which showed an increased overall cancer mortality and mortality of respiratory cancer after long-term exposure to these phenoxy herbicides and dioxins.
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Affiliation(s)
- H Becher
- German Cancer Research Center, Heidelberg, Germany
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Elliott P, Shaddick G, Kleinschmidt I, Jolley D, Walls P, Beresford J, Grundy C. Cancer incidence near municipal solid waste incinerators in Great Britain. Br J Cancer 1996; 73:702-10. [PMID: 8605111 PMCID: PMC2074344 DOI: 10.1038/bjc.1996.122] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
By use of the postcoded database held by the Small Area Health Statistic Unit, cancer incidence of over 14 million people living near 72 municipal solid waste incinerators in Great Britain was examined from 1974-86 (England), 1974-84 (Wales) and 1975-87 (Scotland). Numbers of observed cases were compared with expected numbers calculated from national rates (regionally adjusted) after stratification by a deprivation index based on 1981 census small area statistics. Observed-expected ratios were tested for decline in risk with distance up to 7.5 km. The study was conducted in two stages: the first involved a stratified random sample of 20 incinerators; the second the remaining 52 incinerators. Over the two stages of the study was a statistically significant (P<0.05) decline in risk with distance from incinerators for all cancers combined, stomach, colorectal, liver and lung cancer. Among these cancers in the second stage, the excess from 0 to 1 km ranged from 37% for liver cancer (0.95) excess cases 10(-5) per year to 5% for colorectal cancer. There was evidence of residual confounding near the incinerators, which seems to be a likely explanation of the finding for all cancers, stomach and lung, and also to explain at least part of the excess of liver cancer. For this reason and because of a substantial level of misdiagnosis (mainly secondary tumours) found among registrations and death certificates for liver cancer, further investigation, including histological review of the cases, is to be done to help determine whether or not there is an increase in primary liver cancer in the vicinity of incinerators.
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Affiliation(s)
- P Elliott
- Small Area Health Statistics Unit, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK
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Whysner J, Williams GM. 2,3,7,8-Tetrachlorodibenzo-p-dioxin mechanistic data and risk assessment: gene regulation, cytotoxicity, enhanced cell proliferation, and tumor promotion. Pharmacol Ther 1996; 71:193-223. [PMID: 8910955 DOI: 10.1016/0163-7258(96)00068-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been found to cause several tumor types in rodents, but TCDD has not been proven to cause cancer in humans, although there have been reported associations. TCDD does not bind to DNA, and indirect tests for DNA damage have been mostly negative. Tumorigenicity by TCDD in rodents has been linked to cellular necrosis, enhanced cell proliferation and tumor promotion. TCDD binds to the Ah receptor, which induces CYP1A1. This binding may be involved in tumorigenicity in rodents; however, additional TCDD-induced toxic changes appear to be required. Biopersistence and organ distribution may play an important role in TCDD dosage extrapolation to humans, but these have not been adequately determined.
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Affiliation(s)
- J Whysner
- Toxicology and Risk Assessment Program, American Health Foundation, Valhalla, NY 10595-1599, USA
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Abstract
Dioxins and related compounds are chlorinated aromatic hydrocarbons that are persistent in both environmental and biological samples. Many members of this class of compounds produce a similar spectrum of toxicity which is mediated by interaction with the Ah receptor. The toxic effects of these chemicals can best be described by their actions as growth dysregulators. Dioxins disrupt normal homeostatic processes that tightly regulate cellular growth and differentiation. Disruption in these processes produce a variety of toxicities and pathologies. The available data indicate that humans are sensitive to the toxic effects of these chemicals. Clearer definition of human responses and the body burdens associated with such effects requires more research. Comprehensive risk assessments of dioxins should include all Ah receptor ligands such as the halogenated dibenzofurans and biphenyls.
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Affiliation(s)
- M J DeVito
- Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill 27599, USA
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48
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Wahrendorf J. Design of studies for validation of biomarkers of exposure and their effective use in environmental epidemiology. Toxicology 1995; 101:89-92. [PMID: 7631326 DOI: 10.1016/0300-483x(95)03021-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Studies in environmental epidemiology suffer from the problem that precise assessment of relevant exposures is difficult to undertake, in particular on an individual level. There is much hope that biomarkers may help to move to much more specific studies. However, a variety of issues on the role of biomarkers and their validity need to be clarified beforehand. This paper summarizes issues of the design of studies for validation of biomarkers. Emphasis must be on collecting concurrent information on external dose and related biomarker status (internal dose) for individual subjects.
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Affiliation(s)
- J Wahrendorf
- Division of Epidemiology, German Cancer Research Center, Heidelberg
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Pohl H, DeRosa C, Holler J. Public health assessment for dioxins exposure from soil. CHEMOSPHERE 1995; 31:2437-2454. [PMID: 7670858 DOI: 10.1016/0045-6535(95)00114-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Dioxins are among the most toxic anthropogenic chemicals in the environment. Their toxicity has been extensively studied in both humans and animals. Dioxin-contaminated soil may result in dioxins occurring in a food chain. This is especially important for the general population. It has been estimated that about 98% of exposure to dioxins is through the oral route. In the 1980s, a concentration level of 1 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in soil was specified as "a level of concern," based on cancer effects. However, recent studies indicate that end points other than cancer are also of concern. A health risk analysis scenario based on health effects of TCDD other than cancer is discussed and compared with the projected intake from 1 ppb TCDD in soil.
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Affiliation(s)
- H Pohl
- Division of Toxicology, U.S. Department of Health and Human Services, Atlanta, Georgia 30333, USA
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Scheuplein RJ, Bowers JC. Dioxin--an analysis of the major human studies: comparison with animal-based cancer risks. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 1995; 15:319-333. [PMID: 7604166 DOI: 10.1111/j.1539-6924.1995.tb00325.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Several major epidemiological studies have reported significant mortality rates (SMRs) for both rare cancers (soft tissue sarcoma, non-Hodgkin's, lymphoma, liver) and the more common cancers (lung, colon, etc), all allegedly caused by TCDD. In this paper, we use the potency of TCDD in animals to establish a plausible worst case cancer risk and ask whether its likely that TCDD is responsible for the epidemiological findings assuming the animal carcinogenic potency is applicable to the conditions of human exposure. Two new features of the technique are the use of measured TCDD blood levels in both animals and humans for dose scale-up and the calculation of an integrated life-time exposure for the exposed workers using measured blood levels. On the basis of the stated assumptions it appears unlikely that any of the major epidemiological studies, with the possible exception of the NIOSH study have adequate power to detect the common cancers potentially caused by TCDD.
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Affiliation(s)
- R J Scheuplein
- Weinburg Consultant Group Inc., Washington, D.C. 20036-2400, USA
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