Establishing a total allowable concentration of o-toluidine in drinking water incorporating early lifestage exposure and susceptibility
| Autor: | Virunya S. Bhat, Clifton J McLellan, J. Caroline English, Gwendolyn L. Ball |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Male
medicine.medical_specialty Toluidines Physiology Toxicology Mice Reference Values Toxicity Tests Epidemiology medicine Animals Humans Potency Bladder cancer Chemistry Drinking Water Incidence (epidemiology) Age Factors Cancer Environmental Exposure General Medicine medicine.disease Rats o-Toluidine Female Risk assessment Water Pollutants Chemical Exposure data |
| Zdroj: | Regulatory Toxicology and Pharmacology. 64:269-284 |
| ISSN: | 0273-2300 |
| DOI: | 10.1016/j.yrtph.2012.08.011 |
| Popis: | o-Toluidine is a monocyclic aromatic amine present in the formulation of some materials that contact drinking water. NSF/ANSI 61 Annex A (2011) and US EPA (2005a) risk assessment guidelines were used to determine an acceptable drinking water level. Occupational exposure to o-toluidine is associated with an increased risk of bladder cancer but human disease rates could not be used to establish risk values due to inadequate exposure data and coexposures in the epidemiology cohorts. Chronic dietary exposure to o-toluidine hydrochloride was associated with benign and malignant tumors in both sexes of F344 rats and B6C3F1 mice. o-Toluidine is genotoxic in vitro and in vivo. A 10−5 cancer risk level was extrapolated from the human equivalent BMDL10 of 13 mg/kg-day for the combined incidence of papillomas and carcinomas of the bladder transitional epithelium in female rats. Considering varying susceptibility to tumor development at different life stages, the unit risk was modified to incorporate potency adjustments for early-life exposures. A framework for lifestage adjustment is presented that makes assumptions evident. For this assessment, the lifetime unit risk derived was ∼2-fold greater than the unadjusted adult lifetime unit risk, and the resulting Total Allowable Concentration in drinking water is 20 μg/L. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect