3,4-dichloroaniline

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original report not yet available, cited in EU risk assessment

Data source

Reference

Reference 1

Reference Type:

publication

Title:

A 2-week subchronic inhalation study on 3,4-dichloroaniline in rats

Author:

Kinney, LA et al.

Year:

1987

Bibliographic source:

the toxicologist 7(1): 192

Reference 2

Reference Type:

other: study report; no access

Title:

Unnamed

Year:

1986

Reference 3

Reference Type:

secondary source

Title:

3,4-dichloroaniline (3,4-DCA)

Author:

EU-Risk Assessment Report

Year:

2006

Bibliographic source:

EUR 22235 EN; ISSN 1018-5593

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.8 (Subacute Inhalation Toxicity: 28-Day Study)

Deviations:

yes

Remarks:

; 14 days

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

3,4-dichloroaniline

EC Number:

202-448-4

EC Name:

3,4-dichloroaniline

Cas Number:

95-76-1

Molecular formula:

C6H5Cl2N

IUPAC Name:

3,4-dichloroaniline

Details on test material:

- Name of test material (as cited in study report): 3,4-dichloroaniline
- Analytical purity: no data

Test animals

Species:

rat

Strain:

other: CRl:CD_BR

Sex:

male

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose/head only

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: vapour

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

6 h/d

Frequency of treatment:

5 d/week

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
10 mg/m³
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
45 mg/m³
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
200 mg/m³
Basis:
nominal conc.

No. of animals per sex per dose:

20 male per dose

Control animals:

yes, concurrent no treatment

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Details on results:

see remarks on results

Effect levels

Dose descriptor:

LOAEC

Effect level:

10 mg/m³ air (nominal)

Sex:

male

Basis for effect level:

other: overall effects

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

3,4-dichloroaniline caused dose-dependent methemoglobinemia in all exposed rats (2.5-, 5.0- and 40 -fold increases over control values, respectively) No biological changes in response to the methemoglobinemia were observed at 10 mg/m³. At 45 and 200 mg/m³, rats had accumulations of hemosiderin in the spleen. at 200 mg/m³, rats had elevated spleen weights and extramedullary hematopoeisis in the spleen. These rats also had depressed erythrocyte count, hemoglobin concentration and hematocrit and elevated platelet count and mean corpuscular volume.

These changes are suggestive of increased erythrocyte destruction at 45 and 200 mg/m³, with a resultant compound-related anemia and enhanced erythropoeisis at 200 mg/m³.

Applicant's summary and conclusion

Executive summary:

Kinney, LA (1986)

Test atmospheres containing both vapour and solid particles of 0, 10, 45 or 200 mg/m³ of 3,4-dichloroaniline (99.35% purity) were exposed for 2 weeks (nose-only, 6 hours/day, 5 days/week) to male Crl:CD BR rats (Kinney, 1986). From a total of 20 rats per group 10 rats were used to determine toxic effects, 5 of which were killed after 10th exposure and 5 rats per group were allowed to recover for 14 days post-exposure. Testing parameters included urinalysis after the 9th exposure, haematology and clinical chemistry examinations on day 10 of treatment and on day 14 of recovery, weighing of 6 organs and histopathological examinations of 28 organs/tissues. The remaining 10 rats per groups were used to monitor methaemoglobin level alternately on each second day for half of each group. For these rats no other data are reported due to the potentially confounding effects of repeated bleeding. Time points of methaemoglobin analyses immediately after blood sampling are of critical value (Beutler et al., 1995), but were not reported in this study. At the end of treatment, 3,4-dichloroaniline caused dose-dependent methaemoglobinemia in all exposed rats, dose-related increased incidences of minimal accumulation of hemosiderin in the spleen of mid and high dose rats (5/5 rats at high dose, 2/4 rats at mid dose), anemia, significantly elevated spleen weights (absolute and spleen/body weight) and mild extramedullary haematopoiesis in high dose rats. Anemia was characterised by significantly depressed erythrocyte counts (-17% at 200 mg/m³), reduced concentrations of haemoglobin and hematocrit, elevated platelet count and elevated mean corpuscular volume (MCV), MCH, and MCHC after the 10th exposure. Mean methaemoglobin levels were 12.2% (minimum-maximum 10.0-18.4%, except values on treatment-free weekend) in the high and 1.6% (minimum - maximum 1.0-2.1%) in the mid dose group. In the low dose group a significantly raised methaemoglobin level of 0.8% (minimum - maximum 0.7-1.1%) was found. Although these values are within the range of normal values, they are corresponding to an approximately 2.5-fold increase above control (mean methaemoglobin value 0.3%, minimum - maximum. 0.2-0.5%). No other treatment-related changes were found in the 10 mg/m3 group at the end of the treatment period. No significant clinical signs or body weight changes were observed in rats exposed to 10 or 45 mg/m³ of 3,4-dichloroaniline. Rats exposed to 200 mg/m³ had significantly depressed body weights compared to controls after the 1st and 6th exposures; body weights for these rats were generally lower than controls throughout the exposure period. Various non-specific clinical signs (low incidences of dry red nasal and ocular discharges, brown discoloured fur, stained perineum, hair loss) were observed during the exposure period (mainly in the 1st treatment week). During the recovery period, the body weight of rats exposed to 200 mg/m³ remained (non-significantly) lower than that of other groups. Hemosiderosis was still found in mid and high dose animals after 14 days of recovery being more pronounced and more frequent than after the 10th exposure. All rats were affected; the severity was mild in high dose rats and minimal in mid dose animals. Some blood cell parameters (depressed erythrocyte counts (-9.5%), increased MCV) were still changed at 200 mg/m³. The number of erythrocytes were significantly lower in the low and mid dose group (-7.2% and ¿7.4%) than those of the control groups after recovery. Methaemoglobin level of the low dose rats returned to the range of control animals three days after the end of exposure, while methaemoglobin levels in mid and high dose groups remained significantly elevated through the recovery period. No adverse effect was seen in the lungs, trachea and nose examined histopathologically. In this study, the NOAEC for systemic effects was not derived; the NOAEC for local effects on the respiratory tract was 200 mg/m³. With respect to systemic toxic effects at the end of treatment, the concentration of 3,4-dichloroaniline effective to induce hemosiderosis and methaemoglobin concentrations above the normal range was 45 mg/m³. However this concentration is not considered to be the LOAEC, because the erythrocyte counts in the low and mid dose decreased during recovery. Although their values represented only mild anemia, they were significantly below those of control groups after recovery time. The significant increase of methaemoglobin levels at the low dose group in comparison to the control values, the return of increased methaemoglobin levels after the third day of recovery and the delayed effect on erythrocytes during recovery support that 10 mg/m³ represents the LOAEC.