12/15/2023 0 Comments Dichloromethane non reactivity![]() Dermal absorption of dichloromethane has been demonstrated in animals ( McDougal et al. Dichloromethane releases to drinking-water sources are estimated to range between 0.3 and 2.4% of total environmental releases, much lower than the 86–95% estimate for atmospheric releases, with releases to land accounting for 2–12% ( CalEPA 2000). Drinking-water mean concentrations are generally less than one part per billion (ppb), which is below the 5 ppb maximum contaminant level (MCL) ( CalEPA 2000). Concentrations of dichloromethane in food and water are small compared to concentrations in air thus, oral exposures are low. ![]() Average indoor air concentrations collected from urban, suburban, and rural residences between 1990 (after the 1989 ban on hairspray) and 2005 ranged from 0.4 to 3.5 μg/m 3 ( Dawson and McAlary 2009). Indoor inhalation exposures can result from using consumer products containing dichloromethane such as adhesives, spray shoe polishes, paint and adhesive removers, and building materials and furnishings. In 1996, the national average concentration of dichloromethane in outdoor air was 0.47 μg/m 3 ( U.S. Because of its volatility, it is found mostly in air, and the predominant exposure for the general population occurs from inhalation (primarily from industrial emissions and consumer product use). EPA’s Toxic Release Inventory (TRI) database ( ), a total of 3.4 million pounds of dichloromethane was released into the environment in the United States ( U.S. In this commentary, we summarize exposure sources and the major findings, advancements, critical issues, and future research needs identified in the IRIS assessment, particularly with respect to the physiologically based pharmacokinetic (PBPK) model structure, approaches used to incorporate sensitivity based on genotype, and other sources of variability in the human population.ĭichloromethane (or methylene chloride) is an organic solvent that has been used extensively in industrial settings (e.g., as an extraction solvent and as a metal cleaner) and consumer products (e.g., paint removers). ![]() Environmental Protection Agency (EPA) released an updated Toxicological Review of Dichloromethane (Methylene Chloride) ( U.S. ![]() In 2011, the Integrated Risk Information System (IRIS) of the U.S. Human health effects of dichloromethane: key findings and scientific issues. Innovations in the IRIS assessment include estimation of cancer risk specifically for a presumed sensitive genotype (GST-theta-1+/+), and PBPK modeling accounting for human physiological distributions based on the expected distribution for all individuals 6 months to 80 years of age.Ĭonclusion: The 2011 IRIS assessment of dichloromethane provides insights into the toxicity of a commonly used solvent.Ĭitation: Schlosser PM, Bale AS, Gibbons CF, Wilkins A, Cooper GS. Although there are gaps in the database for dichloromethane genotoxicity (i.e., DNA adduct formation and gene mutations in target tissues in vivo), the positive DNA damage assays correlated with tissue and/or species availability of functional glutathione S-transferase (GST) metabolic activity, the key activation pathway for dichloromethane-induced cancer. Recent epidemiologic studies of dichloromethane (seven studies of hematopoietic cancers published since 2000) provide additional data raising concerns about associations with non-Hodgkin lymphoma and multiple myeloma. Dichloromethane was classified as likely to be carcinogenic in humans based primarily on evidence of carcinogenicity at two sites (liver and lung) in male and female B6C3F 1 mice (inhalation exposure) and at one site (liver) in male B6C3F 1 mice (drinking-water exposure). Methods: We performed a comprehensive review of primary research studies and evaluation of PBPK models.ĭiscussion: Hepatotoxicity was observed in oral and inhalation exposure studies in several studies in animals neurological effects were also identified as a potential area of concern. Objectives: In this commentary we summarize key results and issues of this review, including exposure sources, identification of potential health effects, and updated physiologically based pharmacokinetic (PBPK) modeling. EPA’s Integrated Risk Information System (IRIS) completed an updated toxicological review of dichloromethane in November 2011.
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