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Description of key information

Nose-only exposure of rats to DEA aerosols for 3 months (OECD TG 413) resulted in a systemic NOAEC of 15 mg/m³ and the NOAEC for local respiratory tract effects was 3 mg/m³. In the multiconstituent substance, DEA is present at a absolute maximum level of 20 %. For the major constituent, TEA, the NOAEC for systemic effects was 0.5 mg/L = 500 mg/m³, the highest dose tested, with local irritation effects at 0.02 mg/L = 20 mg/m³. For the multiconstituent substance the NOEC for systemic exposure is estimated to be 15/0.25 = 60 mg/m³ and for local effects 3/0.25 = 12 mg/m³.

Repeated unoccluded dermal application of ethanolic DEA solutions in subchronic (13 weeks, protocol similar to OECD TG 411) a NOAEL for systemic effects or local skin irritation could not be achieved (LOAEL 32 mg/kg bw in rats; 80 mg/kg bw in mice). The 2 year dermal studies (NTP, 1999, protocol similar to OECD TG 451) with rats and mice also showed non-carcinogenic effects. Critical effects appear to be kidney (nephropathy) and liver toxicity, anaemia and dermal hyperkeratosis/acanthosis. The overall dermal LOAEL based on the 13 week and 2 years studie is concluded to be 8 mg/kg bw/day.  For the major constituent TEA, a dermal NOAEL of 125 mg/kg bw was established. Since DEA is present in the substance at a maximum of 25%, the LOAEL for dermal effects is derived as the LOAEL for DEA divided by 0.25=  8/0.25= 32 mg/kg bw

In rats, subchronic oral treatment with DEA  via the drinking water (protocol similar to OECD TG 408) resulted in a LOAEL of 25/14 mg/kg bw (equal to 320/160 ppm) in males/females. In the subchronic oral study in mice a LOAEL of 104/142 mg/kg bw (equal to 630/630 ppm) was noted in males/females. For the major constituent TEA, the oral NOAEL was 1000 mg/kg bw/day. For the multiconstituent substance where DEA is present at a n absolute maximum of 25%, the LOAEL is estimated to 14/0.25= 56 mg/kg bw /day

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
LOAEL
56 mg/kg bw/day
Study duration:
subchronic
Species:
rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEC
60 mg/m³
Study duration:
subchronic
Species:
rat

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Dose descriptor:
LOAEL
32 mg/kg bw/day
Study duration:
chronic
Species:
rat

Additional information

Nose-only exposure of rats to DEA aerosols for 3 months (BASF AG, 1996 and 2002a, OECD TG 413) resulted in systemic and local effects:

- kidney effects (increased incidences of mild hematuria in both sexes, some increase in renal tubular cells and granular casts in male animals, slight increases in kidney weights, minimal or slight tubular hyperplasia in some female animals and intratubular lithiasis slightly more pronounced than in controls in some male animals);

- adaptive liver effects (mild increases of liver weights and serum alkaline phosphatase serum levels without histopathological findings);

- a mild normochromic microcytic anaemia and some influence on the male reproductive system consisting of diffuse testicular atrophy and minimal to slight atrophy of the prostate was present at the high concentration only.

Furthermore, local effects (respiratory tract irritation, squamous metaplasia of the laryngeal epithelium, inflammatory response) were observed. No functional or morphological evidence of neurotoxicity was observed. The NOAEC for systemic effects was 15 mg/m³ and the NOAEC for local respiratory tract effects was 3 mg/m³.

For TEA, repeated inhalation toxicity was investigated in a sub-acute 28 -day study performed according to OECD TG 412 (BASF AG, 1993) and under GLP conditions, in which Wistar rats (10/sex/dose) were exposed head/nose only to 0, 0.02, 0.1 or 0.5 mg/L TEA for 6 hours/day and 5 days/week. No mortality was observed. No statistically significant differences between groups were observed in body weight, haematology and clinical chemistry. Differences in grip strength were judged not substance-related because of a lack of concentration- or time-related effect. No other abnormalities were observed during neurofunctional testing. A significant difference in red blood cells was observed in males of the mid-dose group compared to controls, but since this deviation was marginal, not observed in females, and not dose-related, this finding was considered of no toxicological significance. Local effects were characterized histopathologically by focal inflammatory changes in the submucosa of the larynx, with a concentration-dependent tendency in incidence and severity. No such effects were observed in females of the low dose, whereas minimal to slight effects were seen in males at this dose. Therefore, 0.02 mg/L was considered to be the NOAEC for local effects in females and the LOAEC for males. Since no systemic effects were observed, the systemic NOAEC was established to be 0.5 mg/L, the highest dose tested.

Repeated unoccluded dermal application of ethanolic DEA solutions in subacute (14 days) and subchronic (13 weeks, protocol similar to OECD TG 411) (NTP, 1992) studies with rats and mice led to mortality at high dose levels (≥500 mg/kg bw in rats; ≥1000 mg/kg bw in mice). In rats, systemic signs of toxicity consisted predominantly of anaemia and nephropathy. In addition, liver weights were increased without a histopathological correlate. In mice, systemic effects occurred mainly in the form of liver and kidney damage. In both species, local skin irritation was observed. A NOAEL for systemic effects or local skin irritation could not be achieved (LOAEL 32 mg/kg bw in rats; 80 mg/kg bw in mice).

The 2 year studies (NTP, 1999, protocol similar to OECD TG 451, see section 7.7) with rats and mice also showed non-carcinogenic effects (see section on carcinogenicity) from the lowest tested dermal dose (8 mg/kg bw/day). Critical effects appear to be kidney (nephropathy) and liver toxicity, anaemia and dermal hyperkeratosis/acanthosis. Besides anaemia, nephropathy was observed at the lowest tested dose in the 13 week dermal toxicity study (32 mg/kg bw/day) in female rats. After 13 weeks effects on the kidneys are not yet masked by ageing and appear a treatment related adverse effect. Therefore, the observation of nephropathy in female rats at the lowest tested dermal dose of 8 mg/kg bw/day in the 2 year study, which was somewhat masked by ageing, is also considered adverse. In males this effect was completely masked by the ageing process after 2 years of exposure. In conclusion, the overall dermal LOAEL based on the 13 week and 2 year studies is concluded to be 8 mg/kg bw/day.

 

TEA was tested in a sub-chronic dermal toxicity study(Battelle Columbus Laboratories, 1987a), Fischer rats were treated with 0, 125, 250, 500, 1000 or 2000 mg/kg bw/day TEA on the skin, 5 days/week for 90 days (13 weeks). 20 animals/sex/dose were exposed, of which 10 "special" animals were used for periodic urinalysis, hematology, and clinical chemistry determinations; and 10 "base" animals were used for collection of clinical observation data, sperm morphology and vaginal cytology evaluations, necropsy with gross examination and tissue collection, and histopathological examination (Battelle, 1987a). No mortality was observed. Topical application of 2000 mg/kg bw resulted in a significant decrease in body weight gain, and grossly visible crusts at the site of application were noted in males and females administered 1000 or 2000 mg/kg bw. Hematologic changes were consistent with the presence of skin inflammation in rats in the 2000 mg/kg bw groups, and clinical chemistry findings of very mild but generally dose-related increases in serum alanine and aspartate aminotransferase activities were suggestive of liver injury. However, sorbitol dehydrogenase activity, which is generally considered to be a better gauge of liver damage, was not increased, and histopathology revealed no evidence of hepatic injury. Aspartate aminotransferase has a wider tissue distribution than sorbitol dehydrogenase, and increased serum activity could be related to minor injury at another site, such as the muscle, rather than to hepatotoxicity. Additionally, some compounds can cause increases in alanine aminotransferase activity in the liver or serum without causing hepatic injury.

Kidney weights increased with increasing dose in male and female rats. Dosed males had decreased urinary protein excretion which likely reflected a change in renal function or an increase in protein reabsorption, as serum protein concentrations were not affected. Although these findings suggest the possibility of protein droplet accumulation or some other form of renal dysfunction or injury, no evidence of hyaline droplet nephropathy or other histopathologic changes that might account for the weight changes was noted.

Lesions at the site of application ranged from no discernable change, through minimal to mild epidermal thickening (acanthosis), to chronic active inflammation, erosion, and ulceration. The dermis was also thickened with inflammation and fibrosis at the higher doses. There was no histological evidence to suggest the development of skin sensitisation or contact dermatitis. NOAEL's for local effects were determined to be 125 and 250 mg/kg bw/day for males and females, respectively. The NOAEL's for systemic effects were established to be 125 and 500 mg/kg bw/day for males and females, respectively, based on kidney effects.

In a sub-chronic dermal toxicity study using an identical experimental set-up as in the study with rats, mice were exposed to 0, 250, 500, 1000, 2000 or 4000 mg/kg bw/day TEA on the skin ((Battelle Columbus Laboratories, 1987b). Findings were similar to those in the rat study. All mice survived to the end of the study. Clinical findings were observed only in mice of the 4000 mg/kg bw group and included scaliness, irritation, and discoloration at the application site for males and females, and skin erosion in one male. The absolute kidney and liver weights of males and females administered 4000 mg/kg bw were greater than those of the vehicle controls; relative kidney weights of males administered 1000 mg/kg bw or greater and females in all dosed groups were also greater than those of the vehicle controls. Microscopic examination of the skin of dosed mice indicated acanthosis and inflammation at the site of application. Acanthosis occurred in all dosed groups and in one vehicle control female; the severity increased with increasing dose in males and females. Inflammation was only observed in males and females in the 4000 mg/kg bw groups and in one female in the 2000 mg/kg bw group. The NOAEL for local effects was determined to be ≤ 250 mg/kg bw/day. NOAEL's for systemic effects were established to be 1000 and ≤ 250 mg/kg bw/day for males and females, respectively, based on kidney effects.

In rats, subchronic oral treatment of DEA via the drinking water (NTP, 1992, protocol similar to OECD TG 408) caused mortality at the high dose in males (5000 ppm). Impaired body weight gains were observed at concentrations equal to or higher than 320 ppm in females and 630 ppm in males. Systemic effects consisted of anaemia, nephrotoxicity, cortical vacuolization of adrenal glands and demyelinization of brain/spinal cord without any neurofunctional finding. In males, damage of reproductive organs in the form of testicular degeneration and associated weight changes and impaired spermatology was observed. Based on anaemia observed, a LOAEL of 25/14 mg/kg bw (equal to 320/160 ppm) was achieved in males/females.

In the subchronic oral study in mice (NTP, 1992, protocol similar to OECD TG 408), mortality was observed in males at ≥5000 ppm and in females at ≥2500 ppm. Body weight gain was decreased in both species at concentrations of 1250 ppm (females) or 2500 ppm (males) and higher. Systemic effects consisted of hepato- and nephrotoxicity and myocardial degeneration. The most sensitive effect was necrotic liver damage at all concentrations. A LOAEL of 104/142 mg/kg bw (equal to 630/630 ppm) was noted in males/females.

 

In a sub-chronic oral toxicity study with TEA, 20 Cox CD rats/sex/dose were exposed to 0, 250, 500 or 1000 mg/kg bw/day in the diet for 91 days (EPA, 1989b). Increased feed efficiency was observed in females of the mid-dose group. No significant differences between groups were observed in hematology and organ weights. Gross pathologic and histopathologic examination did not reveal any treatment-related effects. Thus, the NOAEL was established to be 1000 mg/kg bw/day, the highest dose tested.

Repeated dose toxicity: via oral route - systemic effects (target organ) cardiovascular / hematological: other; urogenital: kidneys

Repeated dose toxicity: inhalation - systemic effects (target organ) respiratory: larynx

Repeated dose toxicity: dermal - systemic effects (target organ) cardiovascular / hematological: other; digestive: liver; urogenital: kidneys; other: skin

Justification for classification or non-classification

DEA is listed on Annex I of Directive 67/548/EEC and classified for repeated dose toxicity after oral exposure (Xn, R48/22). Since DEA is present in the multiconstituent substance at a concentration higher than 10%, this results in the following classification under the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008: STOT RE 2; H373.