Trisodium nitrilotriacetate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1971

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment (pre-OECD /pre-GLP study)

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1971

Report date:

1971

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Ten male albino rats per dose were exposed to micronised NTA at four dose levels, followed by a 14 day observation period and were necropsied afterwards. Mortality and clinical signs were observed during exposure and post exposure period.

GLP compliance:

no

Remarks:

(pre-GLP study)

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Trisodium nitrilotriacetate

EC Number:

225-768-6

EC Name:

Trisodium nitrilotriacetate

Cas Number:

5064-31-3

Molecular formula:

C6H9NO6.3Na

IUPAC Name:

trisodium 2-[bis(carboxylatomethyl)amino]acetate

Details on test material:

- Substance type: pure substance
- Physical state: solid, finely divided powder, pale yellow in colour
- Analytical purity: no data

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- test animals: male Sprague Dawley albino rats
- Source: no data
- Weight at study initiation: 243-293 g

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

not specified

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: glass inhalation chamber
- Exposure chamber volume: 38-liter
- Method of holding animals in test chamber: no data
- System of generating particulates/aerosols: Wright dust Feed or pulse-puff generator
- Method of particle size determination: During certain exposures, atmospheric samples were obtained for aerosol particle size analysis with a Monsanto Cascade Impactor.


TEST ATMOSPHERE
- Brief description of analytical method used: Chamber concentrations were determined gravimetrically during each exposure from every chamber by drawing known volumes of chamber atmosphere through glass fiber filters. The concentration was determined by dividing the quantity
(milligrams) of particulate collected by the total sample volume (liters). The concentration was expressed as mg/l.
- Samples taken from breathing zone: yes


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution and mass median diameters:

Table 1: Particle size distribution from four-day inhalation exposures to XTW-448

Group No. Chamber Conc. mg/l Exposure day "particles < 10 µm
in diameter %" mass median diameter

4 0.174 2 63 8.0
3 83 5.2
5 2.307 1 64 8.2
2 79 4.6
4 72 7.3

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 6 h

Remarks on duration:

on consecutive days

Concentrations:

Desired concentrations:
0, 0.002, 0.02, 0.2, 2.0 mg/l air
Actual chamber concentrations:
0, 0.003, 0.040, 0.174, 2.307 mg/l air

No. of animals per sex per dose:

groups of 10 male Sprague Dawley rats per dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: body weights were recorded immediately prior to the first exposure (Day 1), and on Days 2, 3, 4, 5, 11, and 18
- Necropsy of survivors performed: yes. Necropsy of 5 animals on day 5 and 5 animals on day 18
- Other examinations performed: clinical signs were observed and recorded on days 1, 2, 3, 4 of exposure and at the end of the post exposure period, on day 18.
- no histopathology

Statistics:

no details described in the study
average values

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LC0

Effect level:

2.307 mg/L air

Exp. duration:

4 d

Remarks on result:

other: no deaths; exposure: 6h/day

Mortality:

no mortality was observed neither during the exposure nor during the post exposure period.

Clinical signs:

other: The animals exposed to the three lower concentrations do not show any clinical signs like the control group. Animals exposed to 2.307 mg/l show clinical signs from the first day of exposure, but all signs disappeared till the end of the post exposure peri

Body weight:

no abnomalities (see table 2)

Gross pathology:

Necropsy: Generally, all tissues appeared normal when compared to those corresponding tissues from control animals.

Other findings:

none

Any other information on results incl. tables

Table 2: Development of bodyweight

Group No.		body weight
		day 1	day 2	day 3	day 4	day 5	day 11	day 18
1 (air control)	0.000	277	286	290	290	295	297	323
2	0.003	280	288	287	295	297	308	326
3	0.040	258	262	267	273	281	295	310
4	0.174	256	263	265	271	277	283	307
5	2.307	257	258	254	253	246	269	305

Clinical signs:

No clinical signs observed in the control group and in teh groups exposed to the three lower concentrations.

Clinical signs observed in the group exposed to 2.307 mg/l:

Day 1: All ten rats show salivation, hypoactivity and partially closed eyes. One rat showed a red area around eyes.

Day 2: All ten rats show salivation, hypoactivity, partially closed eyes, nasal exudate and brown crust around eyes. Furthermore three of them showed red area around eyes and nose.

Day 3: All ten rats show salivation, hypoactivity, partially closed eyes, nasal exudate and brown crust around eyes. Furthermore three of them showed red area around eyes and nose.

Day 4: All ten rats show salivation, hypoactivity, partially closed eyes, nasal exudate, brown crust around eyes and decreased rate of respiration. Furthermore three of them showed red area around eyes and nose.

Day 18: All clinical signs disappeared

Necropsy:

Focal and diffuse areas of reddish-brown discoloration were observed on the surface of the lungs of both control rats and those exposed to all concentrations of XTW-448 at the Day 5 and Day 18 necropsy interval. It does not appear that this condition is compound-related; however, these findings will have to be correlated with the results of the microscopic examination of these tissues. Microscopic examinations are not published in this study. Generally, all tissues appeared normal when compared to those corresponding tissues from control animals.

Applicant's summary and conclusion

Interpretation of results:

relatively harmless

Remarks:

Migrated information Criteria used for interpretation of results: not specified

Conclusions:

No mortality was caused by exposure to Na3NTA. Clinical signs were evident at the highest concentration (2.307 mg/l) but disappeared until the end of the post exposure period.

Executive summary:

In a 4 -days repeated inhalation toxicity study 10 male Sprague Dawley rats per dose were exposed to Na3NTA for 6 hours per day (on consecutive days) at concentrations of0, 0.003, 0.040, 0.174, 2.307 mg/l (micronised NTA). Animals then were observed for 14 days.

No mortality was observed after treatment with NTA. All animals of the 2.307 mg/l group showed respiratory, nasal and eye irritation. Animals exposed to the lower concentrations did not show any clinical signs. Clinical signs disappeared within the observation period of 14 days after treatment. Gross observations at necropsy revealed no treatment-related abnormalities.