Toxicity of diethanolamine. 2. Drinking water and topical application exposures in B6C3F1 mice

Toxicity of oleate-based amino protic ionic liquids towards Escherichia coli, Danio rerio embryos and human skin cells

Protic ionic liquids (PILs) have been widely employed with the label of "green solvents'' in different sectors of technology and industry. The studied PILs are promising for corrosion inhibition and lubrication applications in industry. Industrial use of the PILs can transform them in wastes, due to accidental spill or drag in water due to washing, that can reach water bodies. In addition, the handling of the product by the workers can expose them to accidental contact. Thus, the aim of this work is to evaluate the toxicity of PILs 2-hydroxyethylammonium oleate (2-HEAOl), N-methyl-2-hydroxyethylammonium oleate (m-2HEAOl) and bis-2-hydroxyethylammonium oleate (BHEAOl) towards Escherichia coli, zebrafish embryos, model organisms that can be present in water, and human skin cells. This is the first work reporting toxicity results for these PILs, which constitutes its novelty. Results showed that the studied PILs did not inhibit E. coli bacterial growth but could cause human skin cells death at the concentrations of use. LC₅₀ values for zebrafish eggs were 40.21 mg/L for 2HEAOl, 12.92 mg/L for BHEAOl and 32.74 mg/L for m-2HEAOl, with sublethal effects at lower concentrations, such as hatching retarding, low heart rate and absence of free swimming.

Safety Assessment of Diethanolamine and Its Salts as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of diethanolamine and its salts as used in cosmetics. Diethanolamine functions as a pH adjuster; the 16 salts included in this rereview reportedly function as surfactants, emulsifying agents, viscosity increasing agents, hair or skin conditioning agents, foam boosters, or antistatic agents. The Panel reviewed available animal and clinical data, as well as information from previous CIR reports. Since data were not available for each individual ingredient, and since the salts dissociate freely in water, the Panel extrapolated from previous reports to support safety. The Panel concluded that diethanolamine and its salts are safe for use when formulated to be nonirritating. These ingredients should not be used in cosmetic products in which N-nitroso compounds can be formed.

Potential occupational risk of amines in carbon capture for power generation

PURPOSE

While CO2 capture and storage (CCS) technology has been well studied in terms of its efficacy and cost of implementation, there is limited available data concerning the potential for occupational exposure to amines, mixtures of amines, or degradation of by-products from the CCS process. This paper is a critical review of the available data concerning the potential effects of amines and CCS-degradation by-products.

METHODS

A comprehensive review of the occupational health and safety issues associated with exposure to amines and amine by-products at CCS facilities was performed, along with a review of the regulatory status and guidelines of amines, by-products, and CCS process vapor mixtures.

RESULTS

There are no specific guidelines or regulations regarding permissible levels of exposure via air for amines and degradation products that could form atmospheric oxidation of amines released from post-combustion CO2 capture plants. While there has been a worldwide effort to develop legal and regulatory frameworks for CCS, none are directly related to occupational exposures.

CONCLUSIONS

By-products of alkanolamine degradation may pose the most significant health hazard to workers in CCS facilities, with several aldehydes, amides, nitramines, and nitrosamines classified as either known or potential/possible human carcinogens. The absence of large-scale CCS facilities; absence and unreliability of reported data in the literature from pilot facilities; and proprietary amine blends make it difficult to estimate potential amine exposures and predict formation and exposure to degradation products.

Effect of diisopropanolamine upon choline uptake and phospholipid synthesis in Chinese hamster ovary cells

Aminoalcohols differ in mammalian toxicity at least in part based upon their ability to alter the metabolism of phospholipids and to cause depletion of the essential nutrient choline in animals. This study examined the incorporation of diisopropanolamine (DIPA) into phospholipids (PLs) and effects of DIPA upon choline uptake and phospholipid synthesis in Chinese hamster ovary (CHO) cells. Results were compared to those of a related secondary alcohol amine, diethanolamine (DEA), whose systemic toxicity is closely associated with its metabolic incorporation into PLs and depletion of choline pools. DIPA caused a dose-related inhibition of (3)H-choline uptake by CHO cells that was approximately 3-4 fold less potent, based upon an IC50, than that reported for DEA. DIPA, in contrast to DEA, did not cause changes in the synthesis rates of (33)P-phosphatidylethanolamine, (33)P-phosphatidylcholine or (33)P-sphingomyelin at either non-toxic or moderately toxic concentrations. Only approximately 0.004%, of administered (14)C-DIPA was metabolically incorporated into PLs, over 30-fold less than the incorporation of (14)C-DEA under similar conditions. Overall, these data and previous pharmacokinetic and toxicity data obtained in vivo suggests that DIPA is distinct from DEA and lacks significant choline and PL metabolism related toxicity in animals.

Chemical-induced atrial thrombosis in NTP rodent studies

Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To access them, click on the issue link for 33(5), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through www.toxpath.org.

Postnatal development of rat pups after maternal exposure to diethanolamine

BACKGROUND

Diethanolamine (DEA), a widely used surfactant, was administered to pregnant mice at the oral LD10 resulting in failure of pups to grow and thrive through postnatal day (PND) 3 [National Toxicology Program, 1987; York et al., Teratology 37:503-504, 1988]. The toxicity profile for DEA differs among rodent species. This study investigated DEA-induced postnatal toxicity in a second species.

METHODS

Timed-mated Sprague-Dawley rats were dosed (0, 50, 125, 200, 250, or 300 mg DEA/kg/day, p.o.) on gestational days (GD) 6-19. Dams and pups were monitored for body weight, feed/water intake, clinical signs, litter size, and sex ratio. At necropsy (PND 21), maternal liver and kidney weights and number of uterine implantation sites were recorded.

RESULTS

The high-dose group was terminated early due to excessive toxicity. The estimated maternal LD10 was 218 mg/kg/day. Maternal effects included decreased body weight and relative feed intake (>or=200 mg/kg/day), transiently reduced relative water intake (125 and 250 mg/kg/day), and increased absolute kidney weight (>or=125 mg/kg/day). Postimplantation loss (PND 0) and pup mortality (PND 0-4) were increased (>or=200 and >or=125 mg/kg/day, respectively). Pup body weight was reduced (>or=200 mg/kg/day) as late as PND 21.

CONCLUSIONS

This study demonstrates reduced postnatal growth and survival in a second species after gestational exposure to DEA, persistence of toxic effects through the end of lactation, possibly due to long elimination half-life, and maternal and developmental toxicity no-observed-adverse-effect level (NOAELs) (50 mg/kg/day) and lowest-observed-adverse-effect level (LOAELs) (125 mg/kg/day) for oral DEA exposure during embryo/fetal development in the rat.

Review of the carcinogenic activity of diethanolamine and evidence of choline deficiency as a plausible mode of action

Diethanolamine (DEA) is a chemical used widely in a number of industries and is present in many consumer products. Studies by the National Toxicology Program (NTP) have indicated that lifetime dermal exposure to DEA increased the incidence and multiplicity of liver tumors in mice, but not in rats. In addition, DEA was not carcinogenic when tested in the Tg.Ac transgenic mouse model. Short-term genotoxicity tests have yielded negative results. In view of these apparent inconsistencies, we have critically evaluated the NTP studies and other data relevant to assessing the carcinogenic potential of DEA. The available data indicate that DEA induces mouse liver tumors by a non-genotoxic mode of action that involves its ability to cause choline deficiency. The following experimental evidence supports this hypothesis. DEA decreased the hepatic choline metabolites and S-adenosylmethionine levels in mice, similar to those observed in choline-deficient mice. In contrast, DEA had no effect in the rat, a species in which it was not carcinogenic at a maximum tolerated dose level. In addition, a consistent dose-effect relationship had been established between choline deficiency and carcinogenic activity since all DEA dosages that induced tumors in the NTP studies were also shown to cause choline deficiency. DEA decreased phosphatidylcholine synthesis by blocking the cellular uptake of choline in vitro, but these events did not occur in the presence of excess choline. Finally, DEA induced transformation in the Syrian hamster embryo cells, increased S-phase DNA synthesis in mouse hepatocytes, and decreased gap junctional intracellular communication in primary cultured mouse and rat hepatocytes, but all these events were prevented with choline supplementation. Since choline is an essential nutrient in mammals, this mode of action is qualitatively applicable to humans. However, there are marked species differences in susceptibility to choline deficiency, with rats and mice being far more susceptible than other mammalian species including humans. These differences are attributed to quantitative differences in the enzyme kinetics controlling choline metabolism. The fact that DEA was carcinogenic in mice but not in rats also has important implications for human risk assessment. DEA has been shown to be less readily absorbed across rat and human skin than mouse skin. Since a no observed effect level for DEA-induced choline deficiency in mice has been established to be 10 mg/kg/d, this indicates that there is a critical level of DEA that must be attained in order to affect choline homeostasis. The lack of a carcinogenic response in rats suggests that exposure to DEA did not reach this critical level. Since rodents are far more sensitive to choline deficiency than humans, it can be concluded that the hepatocarcinogenic effect of DEA in mice is not predictive of similar susceptibility in humans.

Absorption, distribution, metabolism and excretion of intravenously and dermally administered triethanolamine in mice

Triethanolamine (TEA) is an amino alcohol having widespread applications in consumer goods and as an industrial chemical. A number of relatively high-dose dermal toxicity studies have been conducted in rats and mice reflecting the principal route of human exposure to TEA. The absorption, distribution, metabolism and excretion (ADME) of (14)C-TEA derived radioactivity were determined in male C3H/HeJ mice following dermal application of 2000 mg/kg (neat) or, to characterize blood kinetics, intravenous (iv) injection of 1 mg/kg (14)C-TEA. Balance and excretion data were also collected in mice utilizing several dermal dosing scenarios (1000 mg/kg in acetone, 2000 mg/kg neat, 2000 mg/kg in water) and, for comparative purposes, in male Fischer 344 rats dosed dermally with 1000 mg/kg neat (14)C-TEA. Urine, feces, expired CO(2) (iv) and, where appropriate, blood were collected over a 24- or 48-hour period post-dosing. The half-life for dermal absorption of radioactivity was estimated to be 1.3 hours. Intravenously administered radioactivity was eliminated in a biphasic manner with a prominent initial phase (half-life of 0.3 hr) followed by a slower terminal phase (half-life of 10 hr). Radioactivity was excreted primarily via the urine (49-69%) as unmetabolized TEA, regardless of dosage, route or vehicle used. Fecal excretion of radioactivity comprised 16-28% of dose administered. The body burden at sacrifice (sum of liver, kidney, carcass and non-application site skin) ranged from 3 to 6% of the dose. It was concluded that TEA is absorbed extensively following dermal application to mice at dosages relevant to toxicity testing and that acetone or water vehicles do not appear to significantly alter total uptake. Significantly, the blood kinetics and ADME of TEA in mice and/or rats differs from that of a related chemical, diethanolamine, which appears to be more toxic to rodents than TEA.

Diethanolamine absorption, metabolism and disposition in rat and mouse following oral, intravenous and dermal administration

1. The disposition of [14C]diethanolamine (DEA) (1) was determined in rat after oral, i.v. and dermal administration, and in mouse after dermal administration. 2. Oral administration of DEA to rat was by gavage of 7 mg/kg doses once and after daily repeat dosing for up to 8 weeks. Oral doses were well absorbed but excreted very slowly. DEA accumulated to high concentrations in certain tissues, particularly liver and kidney. The steady-state of bioaccumulation was approached only after several weeks of repeat oral dosing, and the half-life of elimination was approximately 1 week. 3. DEA was slowly absorbed through the skin of rat (3-16% in 48 h) after application of 2-28 mg/kg doses. Dermal doses ranging from 8 to 80 mg/kg were more readily absorbed through mouse skin (25-60%) in 48 h of exposure, with the percent of the applied dose absorbed increasing with dose. 4. Single doses (oral or i.v.) of DEA were excreted slowly in urine (c. 22-25% in 48 h) predominantly as the parent compound. There was minimal conversion to CO2 or volatile metabolites in breath. The profile of metabolites appearing in urine changed after several weeks of repeat oral administration, with significant amounts of N-methylDEA and more cationic metabolites appearing along with unchanged DEA.

Epidemiological health study of a town exposed to chemicals

The purpose of this survey was to assess the health status of community residents exposed to a 16-day release of Catacarb from a nearby refinery and to document the prevalence rates of symptoms and illnesses of this town. The health status of the exposed residents was compared to that of unexposed residents of a demographically similar control town. An epidemiologic study design was used and questionnaires were mailed to all households in both towns. Response rate was 43%. Household cluster effects, gender, education, and race were controlled in the analysis. Questionnaire health data reveal increased reporting of symptoms in the exposed, specifically headaches, respiratory, visual, gastrointestinal, and dermatologic with odds ratios ranging between 1.3 and 3. Exposure relationships with increased symptoms and worsening of illnesses was found.

Toxicology of mono-, di-, and triethanolamine

The chemistry, biochemistry, toxicity, and industrial use of monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) are reviewed. The dual function groups, amino and hydroxyl, make them useful in cutting fluids and as intermediates in the production of surfactants, soaps, salts, corrosion control inhibitors, and in pharmaceutical and miscellaneous applications. In 1995, the annual U.S. production capacity for ethanolamines was 447,727 metric tons. The principal route of exposure is through skin, with some exposure occurring by inhalation of vapor and aerosols. MEA, DEA, and TEA in water penetrate rat skin at the rate of 2.9 x 10(-3), 4.36 x 10(-3) and 18 x 10(-3) cm/hr, respectively. MEA, DEA, and TEA are water-soluble ammonia derivatives, with pHs of 9-11 in water and pHa values of 9.3, 8.8, and 7.7, respectively. They are irritating to the skin, eyes, and respiratory tract, with MEA being the worst irritant, followed by DEA and TEA. The acute oral LD50s are 2.74 g/kg for MEA, 1.82 g/kg for DEA, and 2.34 g/kg for TEA (of bw), with most deaths occurring within 4 d of administration. MEA is present in nature as a nitrogenous base in phospholipids. These lipids, composed of glycerol, two fatty acid esters, phosphoric acid, and MEA, are the building blocks of biomembranes in animals. MEA is methylated to form choline, another important nitrogenous base in phospholipids and an essential vitamin. The rat dietary choline requirement is 10 mg kg-1 d-1; 30-d oral administration of MEA (160-2670 mg kg-1 d-1) to rats produced "altered" liver and kidney weights in animals ingesting 640 mg kg-1 d-1 or greater. Death occurred at dosages of 1280 mg kg-1 d-1. No treatment-related effects were noted in dogs administered as much as 22 mg kg-1 d-1 for 2 yr. DEA is not metabolized or readily eliminated from the liver or kidneys. At high tissue concentrations, DEA substitutes for MEA in phospholipids and is methylated to form phospholipids composed of N-methyl and N, N-dimethyl DEA. Dietary intake of DEA by rats for 13 wk at levels greater than 90 mg kg-1 d-1 resulted in degenerative changes in renal tubular epithelial cells and fatty degeneration of the liver. Similar effects were noted in drinking water studies. The findings are believed to be due to alterations in the structure and function of biomembranes brought about by the incorporation of DEA and methylated DEA in headgroups. TEA is not metabolized in the liver or incorporated into phospholipids. TEA, however, is readily eliminated in urine. Repeated oral administration to rats (7 d/wk, 24 wk) at dose levels up to and including 1600 mg kg-1 d-1 produced histopathological changes restricted to kidney and liver. Lesions in the liver consisted of cloudy swelling and occasional fatty changes, while cloudy swelling of the convoluted tubules and loop of Henle were observed in kidneys. Chronic administration (2 yr) of TEA in drinking water (0, 1%, or 2% w/v; 525 and 1100 mg kg-1 d-1 in males and 910 and 1970 mg kg-1 d-1 in females) depressed body and kidney weights in F-344 rats. Histopathological findings consisted of an "acceleration of so-called chronic nephropathy" commonly found in the kidneys of aging F-344 rats. In B6C3F1 mice, chronic administration of TEA in drinking water (0, 1%, or 2%) produced no significant change in terminal body weights between treated and control animals or gross pathological changes. TEA was not considered to be carcinogenic. Systemic effects in rats chronically administered TEA dermally (0, 32, 64, or 125 mg kg-1 d-1 in males; 0, 63, 125, or 250 mg kg-1 d-1 in females) 5 d/wk for 2 yr were primarily limited to hyperplasia of renal tubular epithelium and small microscopic adenomas. In a companion mouse dermal study, the most significant change was associated with nonneoplastic changes in livers of male mice consistent with chronic bacterial hepatitis.

Toxicity of diethanolamine. 1. Drinking water and topical application exposures in F344 rats

Toxicology studies of diethanolamine were conducted in male and female F344 rats for 13 weeks' duration to characterize and compare effects of exposure in the drinking water with those caused by topical application. Doses of diethanolamine ranged from 160 to 5000 ppm in the drinking water study (equivalent to daily doses of 25-440 mg kg-1 in males and 15-240 mg kg-1 in females) and from 32 to 500 mg kg-1 in the topical application study. Dose-dependent toxic effects due to exposure to diethanolamine included hematological changes (a poorly regenerative, microcytic anemia), as well as toxic responses in the kidney (increased weight, tubular necrosis, decreased renal function, and/or tubular mineralization), brain and spinal cord (demyelination), testis (degeneration of the seminiferous tubules) and skin (site of application: ulceration, inflammation, hyperkeratosis and acanthosis). A no-observed-adverse-effect level was not achieved for hematological changes, nephropathy or hyperkeratosis of the skin. Differences in dose-response between the drinking water and topical application exposures were attributed largely to the limited dermal absorption of this chemical.