3-chloropropane-1,2-diol

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

short-term repeated dose toxicity: inhalation

Remarks:

other: combined repeated dose and reproduction / developmental screening (≠ OECD 422)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD guideline 412 adopted in 1981. This study has acceptable deviations with the new OECD 412 guidline adopted in 2009.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)

Deviations:

yes

Remarks:

only 10 days of exposure instead of 28 days, age of males was a little high (17w instead of 12-13w)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-chloropropane-1,2-diol

EC Number:

202-492-4

EC Name:

3-chloropropane-1,2-diol

Cas Number:

96-24-2

Molecular formula:

C3H7ClO2

IUPAC Name:

3-chloropropane-1,2-diol

Details on test material:

- Name of test material (as cited in study report): α-chlorohydrin
- Source: Duphar BV, Weesp, the Netherlands
- Physical state: colourless liquid
- Purity: > 99.5%
- Ration enantiomers: R-enantiomer:S-enantiomer = 50:50 (±1)
- Lot/batch No.: TCE89J10A
- Stability under test conditions: no data
- Storage condition of test material: in brown glass bottles at 4-6 °C

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga GmbH, Sulzfeld, Germany
- Age at study initiation: 17 weeks (males), 12 weeks (females exposed) and 10 weeks (females used for mating procedures)
- Weight at study initiation: ±565 g (males) and ± 313 g (females)
- Housing: before and after exposure individually housed in suspended stainless steel cages (45-32-18) fitted with wire-mesh floor and front
- Diet: Institute's stock diet, ad libitum
- Water: unfluoridated tap water, ad libitum
- Acclimation period: 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 30-70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose/head only

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: not applicable

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only units from ADG Developments Ltd, Codicote, Hitchin, Herts. SG4 8UB, United Kingdom
- Method of holding animals in test chamber: secured in plastic animal holders (Batelle)
- System of generating particulates/aerosols: High-concentration (18 ppm) obtained by passing 35 l air/min through rotation evaporater (kept at 40°C) filled with α-chlorohydrin. Low- and mid-concentrations generated by using non-rotating evaporators. The lower concentrations (I.e. 1 and 4 ppm) were generated by delivering controlled quantities of test material in water (respectively 1 g/l and 4 g/l) by a roller pump to a heated stainless stell capillary. Compressed air (20 and 30 l/min) was passed over this cappillary. Capillary and compressed air lines were surrounded by a heating coil, with temperature set at 70 °C to reach immediate evaporation
- Temperature in air chamber: 23,1 °C (1 ppm), 23,7 °C (4 ppm) and 22,8 °C (18 ppm)
- Humidity in air chamber: <1 % (initially ca. 20% in low- and mid-concentration)
- Air flow rate (l/min): 20 (low-), 30 (mid-) and 35 (high-concentration)


TEST ATMOSPHERE

- Brief description of analytical method used: Analytical concentration of α-chlorohydrin was measured 1-2 times per exposure day using a total carbon analyser (Ratfisch RS 55) with heating sampling line. Before the study the response of the flame ionization detector (FID) was calibrated by passing a measured amount of air and known volumes of solutions of test material to the carbon analyser. A calibration graph was obtained by plotting the concentration (ppm) against the outpout of the carbon analyser (mm).
Nominal concentration was determined by dividing the total amount of test material used per exposure unit by the total volume of air passed through each exposure unit. Volume of air passed through each exposure unit was checked once per day using a gasmeter.

- Samples taken from breathing zone: no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical concentration of α-chlorohydrin was measured 1-2 times per exposure day using a total carbon analyser (Ratfisch RS 55) with heating sampling line. Before the study the response of the flame ionization detector (FID) was calibrated by passing a measured amount of air and known volumes of solutions of test material to the carbon analyser. A calibration graph was obtained by plotting the concentration (ppm) against the outpout of the carbon analyser (mm). The calibration graph obtained was described by the following equation: Y= 0.40 + 0.18x. The correlation coefficient was 0.99857. The actual concentrations (and standard deviations) were: 1.3 (0.2), 4.8 (1.1) and 18.1 (1.2) ppm
Nominal concentration was determined by dividing the total amount of test material used per exposure unit by the total volume of air passed through each exposure unit. Volume of air passed through each exposure unit was checked once per day using a gasmeter. The nominal concentrations (and standard deviations) were 1.0 (0.3), 5.0 (1.2) and 31.5 (8.9) ppm

The large difference between nominal and actual concentration at the high-concentration level might be explained by saturation and resulting losses onto tubing and/or walls of the exposure unit.

Duration of treatment / exposure:

2 weeks

Frequency of treatment:

6 hours/day, 5 days/week

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
18,1 ppm
Basis:
analytical conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
4,8 ppm
Basis:
analytical conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1,3 ppm
Basis:
analytical conc.

No. of animals per sex per dose:

10 males/concentration (5 males used as satellite group) and 5 females/concentration were used for exposure. For mating 100 untreated females were used.

Control animals:

yes

Details on study design:

- Dose selection rationale: Based on the maximum saturated level as indicated by the sponsor
- Rationale for selecting satellite groups: no data
- Post-exposure recovery period in satellite groups: 30 days

Positive control:

no

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Minimum once per day
- Cage side observations checked: All signs of ill, health, reaction to treatment, and mortality


BODY WEIGHT: Yes
- Time schedule for examinations: Weekly


FOOD CONSUMPTION: YES
-Time schedule: Weekly


WATER CONSUMPTION: No


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: At autopsy on day 16 (3 days after last exposure)
- Anaesthetic used for blood collection: Yes (ether anaesthesia)
- Animals fasted: No data
- How many animals: 5/sex/concentration
- Parameters checked include haemoglobin concentration, packed cell volume, red blood cell count, total white blood cell count, differential white blood cell count, prothrombine time, thrombocyte count, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), mean platelet volume (MPV), plateletdistribution width (PDW), red blood cell distribution width (RDW-SD).


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At autopsy on day 16 (3 days after last exposure)
- Animals fasted: No data
- How many animals 5/sex/concentration:
- Parameters checked include alkaline phosphatase activity (ALP), aspartate aminotransferase activity (ASAT), alanine aminotransferase activity (ALAT), gamma glutamyl transferase activity (γGT), total protein, albumin, ratio albumin to globulin, urea, creatinine, bilirubin total, sodium (Na), potassium (K), chloride (Cl), inorganic phosphate.


URINALYSIS: No



NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes: At necropsy following tissues were fixed: adrenals, heart, kidneys, liver, lungs, trachea, larynx, nose, spleen, testes, epididymides and all gross lesions. Adrenals, kidneys, liver, lungs, testes and epiddymides were weighed.
HISTOPATHOLOGY: Yes, examniation was performed on organs of all animals of control and high-concentration group. Examination was extended to low- and mid-dose group if treatment-related changes were found in a specific organ or tissue in the high-concentration group and after consultation of the sponsor. In the recovery group histopathology of organs or tissues was only to be performed if treatment-related changes were found in a specific organ or tissue of the animals killed three days after last exposure.

Other examinations:

Male fertility examined by mating exposed males with untreated females. Two days after the end of the exposure period all exposed and control males were placed overnight with untreated young adult virgin pro-oestrus females. Matings were on a one-male to one-female basis and vaginal smears were taken the next morning to determine whether mating had occured.
Mating was repeated 6-9 and 27-30 days after the last day of exposure for the recovery and control group. Matings were on a one-male to three-female basis and vaginal smears were taken each morning after pairing to confirm mating had occured. The mating procedure was continued until all 3 females were mated or 4 days had elapsed.

Statistics:

Food intake was analyzed by one way analysis of variance followed by Dunnett's multiple comparison test. Body weights, organ weights, haematology and clinical chemistry was analyzed by one way analysis of variance followed by Dunnett's multiple comparison test or t-test, f the number of observations was too small to apply Dunnett's test. The number of implantations and corpera lutea, pre- and post implantation loss were analyzed by the Kruskall-Wallis test followed by the Mann-Whitney U-test. Fertility index, mortality data and histopathological changes were analyzed by the Fisher exact probability test.

Level of significance considered: p < 0.05

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
Shortly after exposure all animals including the controls appeared ungroomed with red crusts around the eyes. This was due to the stay in the restraining tubes and the low humidity.

BODY WEIGHT AND WEIGHT GAIN
During the exposure period animals of all groups including controls lost weight or showed a decreased body weight gain. On day 14 no effect on growth was observed in both males and females.

FOOD CONSUMPTION
In the first week of the study food consumption was significantly decreased in the high concentration group in both males and females. No other differences were observed during the remaining exposure period and recovery period.

FOOD EFFICIENCY
not examined

WATER CONSUMPTION
not examined

OPHTHALMOSCOPIC EXAMINATION
not examined

HAEMATOLOGY
No statistically significantly differences in red blood cell variables or coagulation variables.

CLINICAL CHEMISTRY
No statistically significantly differences observed

URINALYSIS
not examined

NEUROBEHAVIOUR
not examined

ORGAN WEIGHTS
The mean organ weights absolute and relative to body weights of the exposed animals and the control animals were similar

GROSS PATHOLOGY
One male of the high-concentration group showed an enlarged prostate that was attached to the surrounding tissues. One female of the control group showed an enlarged spleen attached to the abdominal wall and the kidney. Other changes were minimal and considered of minor pathological importance.

HISTOPATHOLOGY
No histopathological changes were observed that could be considered treatment related. Abnormalities observed were common findings in the strain of rats used.

OTHER FINDINGS
The number of matings 2 days after exposure in all groups, including the controls was much lower than normal historical control values. This effect was possibly due to stress by the exposure and handling. No female was pregnant at autopsy on day 13 of pregnancy. This effect was considered treatment related and disappeared within 9 days after the end of the two week exposure period. No other effects on mating, pregnancy and mean number of live implantations and resorptions were observed.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

for male fertility

Effect level:

4 ppm

Sex:

male

Basis for effect level:

other: The adverse effects on fertility were not accompanied by histopathological changes in the testes and epididymides. The reduced fertility was reversible within 9 days after last exposure.

2

Dose descriptor:

NOAEL

Remarks:

subacute toxicity

Effect level:

4 ppm

Sex:

male/female

Basis for effect level:

other: The only effect found at 18 ppm was a reduced food intake during the first week of treatment, no other toxicologically relevant effects were observed

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The NOAEL of α-chlorohydrin for toxicity in male and female rats was 4 ppm according to the authors. However the only effect found at 18 ppm was a reduced food intake during the first week of treatment. As there are no treatment related systemic, toxicologically relevant effects observed we would set the NOAEL at 18 ppm. The NOAEL for effects on male fertility in rats was 4 ppm. Reduced fertility was not accompanied by any histopathological changes in the testes and epididymides. Reduced fertility at 18 ppm was reversible within 9 days after the last exposure.