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Li C, Jin L, Wang W, Xiang M, Wang C, Huang Y, Li S, Lu Z, Zhang J, Yang Z, Li H. Iron-sulphur transformation control for enhancing Cr(VI) removal in flake and nanoscale porous pyrrhotite (Fe 7S 8) added wastewater. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129079. [PMID: 35739692 DOI: 10.1016/j.jhazmat.2022.129079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/18/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Hexavalent chromium (Cr(VI)) contaminated wastewater should be addressed efficiently in the environmental field. In previous applications, nano iron sulfides amendment has not been well controlled for iron-sulfur transformation. In this study, the novel flake and nanoscale porous pyrrhotite (Fe7S8) (FNPP) amendment was synthesized. The iron-sulphur transformation of FNPP was controlled and optimized for enhancing Cr(VI) removal. The specific surface area and average pore diameter of the FNPP amendment reached 115.7 m2/g and 2.1 nm. The maximum adsorption capacity of total chromium reached 66.3 mg/g. The optimized iron-sulphur transformation condition was an initial FNPP and Cr(VI) molar ratio of 8, pH at 5.6, in which the Cr(VI) removal reached 96.5% and all producing S2- was utterly consumed. It is confirmed that S2- fast induced Fe3+/Fe2+ circulation and FNPP has a speedier adsorption rate for Cr(III) than Cr(VI). Fe2+ and S2- mediated the Cr(VI) reduction to Cr(III), thus, much faster Cr(VI) removal was achieved. High efficiency removal mechanism of Cr(VI) was combined with surface adsorption/reduction and solution reduction/precipitation. The research demonstrated that controlling and optimizing the iron-sulphur transformation of Fe7S8 amendment can significantly enhance Cr(VI) removal.
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Affiliation(s)
- Chunyang Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Lide Jin
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Wenbing Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
| | - Minghui Xiang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Chen Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yuan Huang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Siyang Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Zhen Lu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Jin Zhang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Zhiyuan Yang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Hui Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
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Katsayal BS, Sallau AB, Muhammad A. Kinetics and thermodynamics of Cr (VI) reduction by Tamarindus indica methanol leaves extract under optimized reaction conditions. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2022. [DOI: 10.1186/s43088-022-00233-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractEnvironmental contamination with Cr (VI) has recently attracted public attention because of its high concentration in soil and wastewater originating majorly from anthropogenic activities and natural processes. Reduction of Cr (VI) to Cr (III) is a feasible method for minimizing chromium pollution. This work aimed at characterizing the effects of Cr (VI) reduction conditions in a batch experiment such as temperature, hydrogen ion concentration, time, and reactant concentrations, as well as kinetics and thermodynamics of the reaction using Tamarindus indica methanol leaves extract as a reductant. Cr (VI) reduction was meaningfully affected by temperature, hydrogen ion concentration, reaction time, and reactant concentrations. The reaction followed the pseudo-second-order kinetic model (R2 = 0.997) at pH of 2; at the neutral and alkaline pH (7 and 9), the reaction predominantly obeyed first order (R2 = 0.988) and pseudo-first order (R2 = 0.758), respectively. Under various hydrogen ion concentrations, the reaction retains negative free energies, enthalpy change, and a positive entropy. The findings from this study suggested the reaction to be spontaneous, exothermic, and orderly unstable. We concluded that phytocompounds present in tamarind methanol leaves extract demonstrated a strong potentials for converting Cr (VI) to Cr (III) and, thus, could be applicable in Cr (VI) contaminated wastewater treatment.
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Assessment of intestinal injury of hexavalent chromium using a modified in vitro gastrointestinal digestion model. Toxicol Appl Pharmacol 2022; 436:115880. [PMID: 35016909 DOI: 10.1016/j.taap.2022.115880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/21/2021] [Accepted: 01/06/2022] [Indexed: 11/22/2022]
Abstract
Intestinal injury assessment of hexavalent chromium (Cr-VI) in humans is crucial for quantifying assessment of adverse health risk posed by the intake of Cr (VI)-contaminated water. To overcome the deficiency in simulating human gastric reduction and intestinal absorption, we modified the constituents of simulated gastric fluid in in vitro digestion method by adding reductants glutathione (18 μM) and ascorbic acid (180 μM), which incorporated with human intestinal epithelial model to construct an in vitro gastrointestinal digestion (IVGD) model for intestinal injury assessment. Cr-VI bioaccessibility results from IVGD model showed that weak gastric acidity significantly increased the intestinal accessible Cr-VI dose by 22.41-38.43 folds. The time-course intestinal absorption indicated prolongation of intestinal exposure destroyed the intestinal epithelium, and 24 h after Cr-VI treatment was a good time point to perform intestinal absorption and toxicity assessment. A series of cell-based bioassays provided initial warning of adverse effect, suggesting that epithelial integrity exhibited greatest sensitivity to Cr-VI exposure and might be used as a sensitive marker for the toxicity assessment of oral exposure to Cr-VI. Notably, this study provides a feasible strategy for delineation of Cr-VI biotransformation and intestinal injury following ingestion exposure, which contributes to address the toxicity data gap of low-dose exposure in humans and puts forward a reference for intestinal toxicity assessment of other chemicals.
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Alvarez CC, Bravo Gómez ME, Hernández Zavala A. Hexavalent chromium: Regulation and health effects. J Trace Elem Med Biol 2021; 65:126729. [PMID: 33610058 DOI: 10.1016/j.jtemb.2021.126729] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/20/2021] [Accepted: 02/06/2021] [Indexed: 12/16/2022]
Abstract
Despite the knowledge about heavy metals toxicity on humans, its use is widely spread mainly for industrial processes. Chromium is an element that belongs to this group and although it is present in our daily diet, it can also be harmful for humans, causing skin allergies and increasing the risk of lung cancer, among other health effects reported. In this review, we highlight its nutritional role, its toxicokinetic and toxicodynamic in humans, its regulation in the industry and the biomonitoring proposal of this element in blood and urine samples with the aim to control the level of exposure of the workers in military industry and also of the general population.
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Affiliation(s)
- Carla Cedillo Alvarez
- Escuela Militar de Medicina, Universidad del Ejército y Fuerza Aérea, Secretaría de la Defensa Nacional, Mexico; Laboratorio de Morfología Celular, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico
| | - María Elena Bravo Gómez
- Laboratorio de Toxicología y Química y Toxicología Forense, Ciencia Forense, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Araceli Hernández Zavala
- Laboratorio de Morfología Celular, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico.
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Jia J, Li T, Yao C, Chen J, Feng L, Jiang Z, Shi L, Liu J, Chen J, Lou J. Circulating differential miRNAs profiling and expression in hexavalent chromium exposed electroplating workers. CHEMOSPHERE 2020; 260:127546. [PMID: 32758765 DOI: 10.1016/j.chemosphere.2020.127546] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Hexavalent chromium [Cr (Ⅵ)] has extensive applications in industries, and long-term occupational exposure to Cr (Ⅵ) may lead to lung carcinoma and other cancers. While microRNA (miRNA) can take part in carcinogenesis, little is known about its expression profile in the population with Cr (Ⅵ) exposure. Thus, this study aimed to explore miRNA expression profiles in Cr (Ⅵ) exposed workers and to identify the potential biological function of differentially expressed miRNAs. A total of 45 significant differentially expressed miRNAs were identified by the miRNA array. The results of validation showed that miR-19a-3p, miR-19b-3p, and miR-142-3p were downregulated and miR-590-3p and miR-941 were upregulated in the exposure group. Multivariate analysis demonstrated that age, exposure duration and urinary chromium level were associated with one or more miRNAs expression. Target gene analysis indicated that these miRNAs might participate in the regulation of DNA damage-related signaling pathways. Taken together, Cr (Ⅵ) exposure can result in differential expression of miRNAs in occupational workers, and the expression of these miRNAs is correlated with the level and duration of Cr (Ⅵ) exposure, and the differentially expressed miRNAs may participate in DNA damage response.
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Affiliation(s)
- Junlin Jia
- Hangzhou Medical College, Hangzhou, 310053, China
| | - Tao Li
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Chunji Yao
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Junfei Chen
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Lingfang Feng
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Zhaoqiang Jiang
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Li Shi
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Jiaqi Liu
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Junqiang Chen
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China
| | - Jianlin Lou
- Hangzhou Medical College, Hangzhou, 310053, China; Institute of Occupational Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang, 310013, China.
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Bhat VS, Cohen SM, Gordon EB, Wood CE, Cullen JM, Harris MA, Proctor DM, Thompson CM. An adverse outcome pathway for small intestinal tumors in mice involving chronic cytotoxicity and regenerative hyperplasia: a case study with hexavalent chromium, captan, and folpet. Crit Rev Toxicol 2020; 50:685-706. [PMID: 33146058 DOI: 10.1080/10408444.2020.1823934] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Small intestinal (SI) tumors are relatively uncommon outcomes in rodent cancer bioassays, and limited information regarding chemical-induced SI tumorigenesis has been reported in the published literature. Herein, we propose a cytotoxicity-mediated adverse outcome pathway (AOP) for SI tumors by leveraging extensive target species- and site-specific molecular, cellular, and histological mode of action (MOA) research for three reference chemicals, the fungicides captan and folpet and the transition metal hexavalent chromium (Cr(VI)). The gut barrier functions through highly efficient homeostatic regulation of SI epithelial cell sloughing, regenerative proliferation, and repair, which involves the replacement of up to 1011 cells per day. This dynamic turnover in the SI provides a unique local environment for a cytotoxicity mediated AOP/MOA. Upon entering the duodenum, cytotoxicity to the villous epithelium is the molecular initiating event, as indicated by crypt elongation, villous atrophy/blunting, and other morphologic changes. Over time, the regenerative capacity of the gut epithelium to compensate declines as epithelial loss accelerates, especially at higher exposures. The first key event (KE), sustained regenerative crypt proliferation/hyperplasia, requires sufficient durations, likely exceeding 6 or 12 months, due to extensive repair capacity, to create more opportunities for the second KE, spontaneous mutation/transformation, ultimately leading to proximal SI tumors. Per OECD guidance, biological plausibility, essentiality, and empirical support were assessed using modified Bradford Hill considerations. The weight-of-evidence also included a lack of induced mutations in the duodenum after up to 90 days of Cr(VI) or captan exposure. The extensive evidence for this AOP, along with the knowledge that human exposures are orders of magnitude below those associated with KEs in this AOP, supports its use for regulatory applications, including hazard identification and risk assessment.
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Affiliation(s)
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Charles E Wood
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA
| | - John M Cullen
- North Carolina State University, Raleigh, NC, USA.,EPL, Inc., Sterling, VA, USA
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Tumolo M, Ancona V, De Paola D, Losacco D, Campanale C, Massarelli C, Uricchio VF. Chromium Pollution in European Water, Sources, Health Risk, and Remediation Strategies: An Overview. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E5438. [PMID: 32731582 PMCID: PMC7432837 DOI: 10.3390/ijerph17155438] [Citation(s) in RCA: 147] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 01/23/2023]
Abstract
Chromium is a potentially toxic metal occurring in water and groundwater as a result of natural and anthropogenic sources. Microbial interaction with mafic and ultramafic rocks together with geogenic processes release Cr (VI) in natural environment by chromite oxidation. Moreover, Cr (VI) pollution is largely related to several Cr (VI) industrial applications in the field of energy production, manufacturing of metals and chemicals, and subsequent waste and wastewater management. Chromium discharge in European Union (EU) waters is subjected to nationwide recommendations, which vary depending on the type of industry and receiving water body. Once in water, chromium mainly occurs in two oxidation states Cr (III) and Cr (VI) and related ion forms depending on pH values, redox potential, and presence of natural reducing agents. Public concerns with chromium are primarily related to hexavalent compounds owing to their toxic effects on humans, animals, plants, and microorganisms. Risks for human health range from skin irritation to DNA damages and cancer development, depending on dose, exposure level, and duration. Remediation strategies commonly used for Cr (VI) removal include physico-chemical and biological methods. This work critically presents their advantages and disadvantages, suggesting a site-specific and accurate evaluation for choosing the best available recovering technology.
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Affiliation(s)
- Marina Tumolo
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
- Department of Biology, University of Bari, 70126 Bari, Italy
| | - Valeria Ancona
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
| | - Domenico De Paola
- Institute of Biosciences and Bioresources, Italian National Research Council (IBBR-CNR), 70126 Bari, Italy;
| | - Daniela Losacco
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
- Department of Biology, University of Bari, 70126 Bari, Italy
| | - Claudia Campanale
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
| | - Carmine Massarelli
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
| | - Vito Felice Uricchio
- Water Research, Institute-Italian National Research Council (IRSA-CNR), 70132 Bari, Italy; (M.T.); (D.L.); (C.C.); (C.M.); (V.F.U.)
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Suh M, Wikoff D, Lipworth L, Goodman M, Fitch S, Mittal L, Ring C, Proctor D. Hexavalent chromium and stomach cancer: a systematic review and meta-analysis. Crit Rev Toxicol 2019; 49:140-159. [DOI: 10.1080/10408444.2019.1578730] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Mina Suh
- ToxStrategies, Inc, Mission Viejo, CA, USA
| | | | - Loren Lipworth
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael Goodman
- Emory University Rollins School of Public Health, Atlanta, GA, USA
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Recognition of a New Cr(VI)-Reducing Strain and Study of the Potential Capacity for Reduction of Cr(VI) of the Strain. BIOMED RESEARCH INTERNATIONAL 2019; 2019:5135017. [PMID: 30881989 PMCID: PMC6387719 DOI: 10.1155/2019/5135017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 11/14/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022]
Abstract
The biotransformation of hexavalent chromium [Cr(VI)] via Cr(VI)-reducing microorganisms is considered an ecofriendly approach to detoxify Cr(VI). A new Cr(VI)-reducing bacterium named Microbacterium sp. QH-2 was isolated in this study. Scanning electron microscopy (SEM) images showed protrusions on the bacterial surface of strain QH-2 after an 18 h incubation in media under 10 mM Cr(VI) treatment. Results of the experiments on the capacity of reducing Cr(VI) indicated that strain QH-2 could reduce 100% Cr(VI) less than 48-96 h. When media with 4 mM Cr(VI) were incubated, the fastest reduction rate of strain QH-2 could come up to 2.17 mg/L Cr(VI) h−1. Furthermore, strain QH-2 could reduce Cr(VI) over the pH between 7 and 10. The optimum pH to reduce Cr(VI) by strain QH-2 was 9. Strain QH-2 also exhibited a relatively high tolerance even to 20 mM Cr(VI). These results declared that strain QH-2 had the potential to detoxify Cr(VI) in the Cr(VI)-contaminated soil or effluent.
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Thompson CM, Kirman CR, Hays SM, Suh M, Harvey SE, Proctor DM, Rager JE, Haws LC, Harris MA. Integration of mechanistic and pharmacokinetic information to derive oral reference dose and margin-of-exposure values for hexavalent chromium. J Appl Toxicol 2018; 38:351-365. [PMID: 29064106 PMCID: PMC5813206 DOI: 10.1002/jat.3545] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/28/2017] [Accepted: 09/05/2017] [Indexed: 01/18/2023]
Abstract
The current US Environmental Protection Agency (EPA) reference dose (RfD) for oral exposure to chromium, 0.003 mg kg-1 day-1 , is based on a no-observable-adverse-effect-level from a 1958 bioassay of rats exposed to ≤25 ppm hexavalent chromium [Cr(VI)] in drinking water. EPA characterizes the confidence in this RfD as "low." A more recent cancer bioassay indicates that Cr(VI) in drinking water is carcinogenic to mice at ≥30 ppm. To assess whether the existing RfD is health protective, neoplastic and non-neoplastic lesions from the 2 year cancer bioassay were modeled in a three-step process. First, a rodent physiological-based pharmacokinetic (PBPK) model was used to estimate internal dose metrics relevant to each lesion. Second, benchmark dose modeling was conducted on each lesion using the internal dose metrics. Third, a human PBPK model was used to estimate the daily mg kg-1 dose that would produce the same internal dose metric in both normal and susceptible humans. Mechanistic research into the mode of action for Cr(VI)-induced intestinal tumors in mice supports a threshold mechanism involving intestinal wounding and chronic regenerative hyperplasia. As such, an RfD was developed using incidence data for the precursor lesion diffuse epithelial hyperplasia. This RfD was compared to RfDs for other non-cancer endpoints; all RfD values ranged 0.003-0.02 mg kg-1 day-1 . The lowest of these values is identical to EPA's existing RfD value. Although the RfD value remains 0.003 mg kg-1 day-1 , the confidence is greatly improved due to the use of a 2-year bioassay, mechanistic data, PBPK models and benchmark dose modeling.
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Affiliation(s)
| | | | - Sean M Hays
- Summit Toxicology, LLP, Bozeman, MT, 59722, USA
| | - Mina Suh
- ToxStrategies, Inc., Mission Viejo, CA, 92692, USA
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Shil K, Pal S. Metabolic adaptability in hexavalent chromium-treated renal tissue: an in vivo study. Clin Kidney J 2017; 11:222-229. [PMID: 29644063 PMCID: PMC5887570 DOI: 10.1093/ckj/sfx069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/30/2017] [Indexed: 12/17/2022] Open
Abstract
Background Hexavalent chromium [Cr(VI)], an environmental pollutant that originates mostly from anthropogenic sources, is a serious threat to human health. After entering into cells, Cr(VI) is capable of producing excessive free radicals and causing tissue damage. The present study aims to reveal the toxic manifestation of Cr(VI) on the metabolic activity of renal tissue. Methods Male Swiss albino mice were treated orally with potassium dichromate (K2Cr2O7) at a dose of 10 mg/kg body weight for a period of 30 days. Important tricarboxylic acid (TCA) cycle enzyme activities like isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase, as well as the activities of enzymes involved in oxidative phosphorylation such as Nicotinamide adenine dinucleotide (NADH) dehydrogenase, were measured. Additionally, transaminase and protease (pronase, cathepsin and trypsin) activities, tissue protein and free amino nitrogen were estimated in renal tissue. Glucose-6-phosphatase, glucose-6-phosphate dehydrogenase and alkaline phosphatase activities, as well as lactic acid, pyruvic acid and chromium contents, of kidneys were determined following standard protocols. Kidney histology was performed by hematoxylin and eosin staining. Results Cr(VI) suppresses the rate-limiting enzymes of the TCA cycle and oxidative phosphorylation indicating an inhibition of renal ATP production. It decreases protease activity by eliminating the protein substrates and alters the gluconeogenic pathway. Cr(VI) worsens the normophysiological attributes of renal tissue by enhancing the activity of alkaline phosphatase, pointing towards kidney disease. Histopathological observations confirmed these biochemical results through the presence of chronic tubular nephritis and altered glomerular structure. Cr(VI) retention occurs to a greater extent in renal tissue, which intensifies the toxic manifestation of this pollutant in the kidney. Conclusions Cr(VI) disrupts the metabolic interaction between carbohydrates and proteins in mammalian renal tissue.
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Affiliation(s)
- Kanu Shil
- Nutritional Biochemistry and Toxicology Laboratory, Department of Human Physiology, Tripura University, Suryamaninagar, West Tripura, India
| | - Sudipta Pal
- Nutritional Biochemistry and Toxicology Laboratory, Department of Human Physiology, Tripura University, Suryamaninagar, West Tripura, India
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Thompson CM, Rager JE, Suh M, Ring CL, Proctor DM, Haws LC, Fry RC, Harris MA. Transcriptomic responses in the oral cavity of F344 rats and B6C3F1 mice following exposure to Cr(VI): Implications for risk assessment. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2016; 57:706-716. [PMID: 27859739 PMCID: PMC5215477 DOI: 10.1002/em.22064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/27/2016] [Indexed: 05/13/2023]
Abstract
Exposure to hexavalent chromium [Cr(VI)] in drinking water was previously reported to increase oral tumor incidence in F344 rats. To investigate the mode of action for these tumors, transcriptomic profiles in oral mucosa samples of F344 rats and B6C3F1 mice were analyzed following exposure to 0.1-180 ppm Cr(VI) for 7 or 90 days. In rats, genome-wide microarray analyses identified no significantly differentially expressed genes (DEGs) at either time point. In mice, 14 and 1 DEGs were respectively identified after 7 and 90 days of exposure. Therefore, relaxed statistical criteria were employed to identify potential DEGs (pDEGs), followed by high-throughput benchmark dose modeling to identify responsive pDEGs for pathway enrichment analysis. This identified 288 and 168 pDEGs in the rat oral mucosa, of which only 20 and 7 showed evidence of dose-response. No significant pathway enrichment was obtained with either pDEG or dose-responsive pDEG lists. Similar results were obtained in mice. These analyses indicate a negligible transcriptional response in the oral mucosa of both species. Comparison of the total number of gene changes in the oral mucosa of rats and mice with responses in the duodenum of animals from the same study demonstrated remarkable dose-response concordance across tissues and species as a function of tissue chromium concentration. The low chromium levels in the oral mucosa and negligible transcript response are consistent with an absence of tissue lesions. These findings are used to compare the merits of linear and nonlinear approaches for deriving toxicity criteria based on the oral tumors in rats. Environ. Mol. Mutagen. 57:706-716, 2016. © 2016 The Authors. Environmental and Molecular Mutagenesis Published by Wiley Periodicals, Inc.
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Affiliation(s)
| | | | - Mina Suh
- ToxStrategies, IncMission ViejoCalifornia
| | | | | | | | - Rebecca C. Fry
- Department of Environmental Sciences and EngineeringGillings School of Global Public HealthChapel HillNorth Carolina
- Curriculum in Toxicology, University of North Carolina at Chapel HillChapel HillNorth Carolina
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Kirman CR, Suh M, Hays SM, Gürleyük H, Gerads R, De Flora S, Parker W, Lin S, Haws LC, Harris MA, Proctor DM. Reduction of hexavalent chromium by fasted and fed human gastric fluid. II. Ex vivo gastric reduction modeling. Toxicol Appl Pharmacol 2016; 306:120-33. [DOI: 10.1016/j.taap.2016.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/29/2016] [Accepted: 07/04/2016] [Indexed: 10/21/2022]
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