Human Health Effects of Dichloromethane: Key Findings and Scientific Issues

Abstract

Background: The U.S. EPA’s Integrated Risk Information System (IRIS) completed an updated toxicological review of dichloromethane in November 2011.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.Methods: We performed a comprehensive review of primary research studies and evaluation of PBPK models.Discussion: 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. 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 B6C3F1 mice (inhalation exposure) and at one site (liver) in male B6C3F1 mice (drinking-water exposure). 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. 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. 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.Conclusion: The 2011 IRIS assessment of dichloromethane provides insights into the toxicity of a commonly used solvent.Citation: Schlosser PM, Bale AS, Gibbons CF, Wilkins A, Cooper GS. 2015. Human health effects of dichloromethane: key findings and scientific issues. Environ Health Perspect 123:114–119; http://dx.doi.org/10.1289/ehp.1308030

Recent Advances in the Catalytic Production of Platform Chemicals from Holocellulosic Biomass

“…Therefore it is employed with ethanol and gas to create an alternative fuel that can be used as a substitute for gasoline (P‐Series Fuel). Furthermore, MTHF is a promising substitute for dichloromethane (DCM), a common solvent used in pharmaceutical and agricultural products and a probable carcinogen …”

“…The biochemical pathway usually takes 2–4 days and exhausts a significant amount of calcium hydroxide that is used to balance the pH value of the reaction medium, hence producing a large amount of waste. However, this route faces two main cost related drawbacks that are associated with sugars used as feedstock and sterilization . Nevertheless, lignocellulosic biomass is forecast to decrease in cost and it holds potential to replace conventional feedstocks to produce LA .…”

Dietary quercetin abrogates hepatorenal oxidative damage associated with dichloromethane exposure in rats

“…Acute and chronic exposure to DCM reportedly poses great threat to humans and ecosystems due to its toxicity, persistence, and bioaccumulation in the food chain (Tobajas et al, 2016). DCM, due to its lipophilicity is easily absorbed and metabolized in humans and animals resulting in multiple organ damage (Schlosser et al, 2015). Further, DCM has been shown to undergo both microsomal oxidation and cytosolic glutathione-conjugation pathways in the liver (Evans & Caldwell, 2010;Schlosser et al, 2015).…”

“…DCM, due to its lipophilicity is easily absorbed and metabolized in humans and animals resulting in multiple organ damage (Schlosser et al, 2015). Further, DCM has been shown to undergo both microsomal oxidation and cytosolic glutathione-conjugation pathways in the liver (Evans & Caldwell, 2010;Schlosser et al, 2015). Epidemiological findings indicated that exposure to DCM is common in workplace leading to toxicity (Bonfiglioli et al, 2014).…”

Activated MIL-53(Al) for Efficient Adsorption of Dichloromethane and Trichlormethane

“…Dichloromethane (CH 2 Cl 2 ) and trichlormethane (CHCl 3 ) as two kinds of volatile organic compounds (VOCs) are the pollutants in the air, and how to deal with them has become a focus of the society (Narita et al, 1986;Schlosser et al, 2014;Kujawa et al, 2015). A number of add-oncontrol techniques, including filtration, adsorption, membrane separation, ionization, ozonation, and photocatalysis, have been developed to remove them from contaminated air (Koh et al, 2009;Ma et al, 2009).…”