The toxicity of crude 4-methylcyclohexanemethanol (MCHM): review of experimental data and results of predictive models for its constituents and a putative metabolite.

Crude 4-methylcyclohexanemethanol (MCHM) is an industrial solvent used to clean coal. Approximately 10 000 gallons of a liquid mixture containing crude MCHM were accidently released into the Elk River in West Virginia in January 2014. Because of the proximity to a water treatment facility, the contaminated water was distributed to approximately 300 000 residents. In this review, experimental data and computational predictions for the toxicity for crude MCHM, distilled MCHM, its other components and its putative metabolites are presented. Crude MCHM, its other constituents and its metabolites have low to moderate acute and subchronic oral toxicity. Crude MCHM has been shown not to be a skin sensitizer below certain doses, indicating that at plausible human exposures it does not cause an allergic response. Crude MCHM and its constituents cause slight to moderate skin and eye irritation in rodents at high concentrations. These chemicals are not mutagenic and are not predicted to be carcinogenic. Several of the constituents were predicted through modeling to be possible developmental toxicants; however, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedicarboxylic acid and dimethyl 1,4-cyclohexanedicarboxylate did not demonstrate developmental toxicity in rat studies. Following the spill, the Centers for Disease Control and Prevention recommended a short-term health advisory level of 1 ppm for drinking water that it determined was unlikely to be associated with adverse health effects. Crude MCHM has an odor threshold lower than 10 ppb, indicating that it could be detected at concentrations at least 100-fold less than this risk criterion. Collectively, the findings and predictions indicate that crude MCHM poses no apparent toxicological risk to humans at 1 ppm in household water.

Effect of chronic exposure to two components of Tritan copolyester on Daphnia magna, Moina macrocopa, and Oryzias latipes, and potential mechanisms of endocrine disruption using H295R cells.

Tritan copolyester is a novel plastic form from Eastman Company utilizing three main monomers, 1,4-cyclohexanedimethanol (CHDM), dimethyl terephthalate (DMT), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Despite Tritan has been widely applied for plastic bottles, the effects of long-term exposure to these compounds have seldom been investigated. We investigated chronic effects and endocrine disruption potential of CHDM and terephthalic acid (TPA), main mammalian metabolite formed from DMT, using crustacean Daphnia magna and Moina macrocopa, and freshwater fish (Oryzias latipes). The effects on sex hormone balance and the associated mechanisms were also investigated by use of H295R cells. In chronic toxicity test, D. magna showed significant decrease in reproduction (number of young per female) after exposure to 10 mg/L TPA. In early life stage exposure using O. latipes, significant decrease of juvenile survival and weight were observed in fish exposed to 10 mg/L and ≥1 mg/L CHDM, respectively. Expressions of vtg2 mRNA in fish exposed to CHDM and those of cyp19b, star, cyp17, and cyp19a mRNAs in fish exposed to TPA were significantly up-regulated. The results of H295R cell assay also showed that both chemicals at high concentrations could alter sex hormone production in steroidogenic pathway. The effective concentrations of the tested compounds were several orders of magnitude greater than the concentrations can be detected in ambient waters. Further in vivo and in vitro studies will be needed to investigate the effect of co-polymer on endocrine disruption.

Safety assessment of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', when used as an additive in all types of polyolefins. The substance is a polymer containing ≤ 13% w/w of a low molecular weight fraction (LMWF, < 1000 Da). A polyethylene sample with 0.15% w/w of the substance was used in a comprehensive set of migration tests with food simulants. The specific migration was up to 0.014 and 0.023 mg/kg in 4% acetic acid and 10% ethanol, respectively. Migration into olive oil was estimated by the Panel to be up to 5.3 mg/kg under worst-case conditions of use. The migrating LMWF species were comprehensively identified. Those without phosphorous were either without alerts for genotoxicity or listed in Regulation (EU) 10/2011 with worst-case migrations well below their respective specific migration limits. Toxicological studies were performed using phosphite and phosphate versions of the substance enriched in its LMWF. The substance does not raise a concern for genotoxicity. From a repeated dose 90-day oral toxicity study in rats with a 50:50 phosphite:phosphate blend, the Panel identified a NOAEL of 250 mg/kg bw per day for each component of the blend. No delayed neurotoxicity in hens was observed. The CEP Panel concluded that the substance does not raise a safety concern for the consumer if its LMWF is not higher than 13% w/w, if it is used at up to 0.15% w/w in polyolefin materials and articles intended for contact with all food types, except for infant formula and human milk, for long-term storage at room temperature and below, after hot-fill and/or heating up to 100°C for up to 2 h, and if its migration does not exceed 5 mg/kg food.

A Rapid Thermal Absorption Rate and High Latent Heat Enthalpy Phase Change Fiber Derived from Bio-Based Low Melting Point Copolyesters.

A series of poly(butylene adipate-co-hexamethylene adipate) (PBHA) copolymers with different content of 1,4-cyclohexanedimethanol (CHDM) was synthesized via one-step melt polymerization. The PBHA copolymer with 5 mol% CHDM (PBHA-C5) exhibited a low melting point (Tm) and high enthalpy of fusion (∆Hm) of 35.7 °C and 43.9 J g-1, respectively, making it a potential candidate for an ambient temperature adjustment textile phase change material (PCM). Polybutylene terephthalate (PBT) was selected as the matrix and blended at different weight ratios of PBHA-C5, and the blended samples showed comparable Tm and ∆Hm after three cycles of cooling and reheating, indicating good maintenance of their phase changing ability. Samples were then processed via melt spinning with a take-up speed of 200 m min-1 at draw ratios (DR) of 1.0 to 3.0 at 50 °C. The fiber's mechanical strength could be enhanced to 2.35 g den-1 by increasing the DR and lowering the PBHA-C5 content. Infrared thermography showed that a significant difference of more than 5 °C between PBT and other samples was achieved within 1 min of heating, indicating the ability of PBHA-C5 to adjust the temperature. After heating for 30 min, the temperatures of neat PBT, blended samples with 27, 30, and 33 wt% PBHA-C5, and neat PBHA-C5 were 53.8, 50.2, 48.3, 47.2, and 46.5 °C, respectively, and reached an equilibrium state, confirming the temperature adjustment ability of PBHA-C5 and suggesting that it can be utilized in thermoregulating applications.