Chloramide

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

data not available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment. Nevertheless, a small number of animals were used (6 animals instead of 20/ group).

Data source

Reference

Reference Type:

publication

Title:

Effect of chlorine and monochloramine in drinking water on the developing rat fetus.

Author:

Abdel-Rahman M.S., Berardi M.R. and Bull R.J.

Year:

1982

Bibliographic source:

Journal of applied toxicology, vol. 2, No. 3, 1982

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Determination of the teratogenicity of monochloramine in rats, when administered prior to and throughout gestation. Six animals per group were administered 0, 1, 10 or 100 mg/l NH2Cl daily in the drinking water. After treatment for 2 1/2 months, the females were placed in the cages of untreated males in a ratio of 1 male : 3 females. Females with sperm-positive vaginal smears were placed in their original cages and allowed to drink their respective solutions throughout gestation. On day 20 of gestation females were killed and the numbers of live and dead foetuses were noted as well as resorptions. Individual foetal weights were recorded and a gross examination for external malformations was made.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Chloramide

EC Number:

234-217-9

EC Name:

Chloramide

Cas Number:

10599-90-3

Molecular formula:

ClH2N

IUPAC Name:

chloranamine

Test material form:

other: in solution

Details on test material:

Monocloramine was synthesized by adding stock chlorine to a bicarbonate buffer of pH 9.0-9.1 (13.13 g sodium bicarbonate and 1.32 g sodium carbonate per liter of water). The following equation was used to determine the amount of chlorine to be added to the buffer:
axb/c=ml stock chlorine where a = desired monochloramine concentration, b = final volume of monochloramine solution, and c = chlorine concentration in mg/l (as determine by titration). Then ammonium hydroxide was added as follow: ax0.0067y= ml NH4OH added
The factor 0.0067 provides the volume of NH4OH to give equimolar amounts of Cl:NH3. The concentration of monochloramine was then determined by titrating according to the DPD method of Palin. This method also detects any small amounts of di- or tri-chloramines present in the solution. No trichloramine was found in the solutions, and the level of dichloramine was less than 1% of the monochloramine concentration.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: data not available
- Age at study initiation: Mature virgin female rat
- Weight at study initiation: 225-250 g
- Fasting period before study:
- Housing: three per cage
- Diet : ad libitum
- Water : ad libitum
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 25
- Humidity (%): 50
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 h light/ dark cycle.

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentration of monochloramine was then determined by titrating according to DPD method of Palin. This method also detects any small amounts of di- or trichloramines present in the solution. No trichloramine was found in the solutions, and the level of dichloramine was less than 1 % of the monochloramine concentration.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1 male : 3 females
- Length of cohabitation: no data
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

2 1/2 months prior to and throughout gestation.

Frequency of treatment:

Daily in the drinking water.

Duration of test:

2 1/2 months + breeding period + gestation period

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 1, 10 or 100 mg/l
Basis:
nominal in water

No. of animals per sex per dose:

6 animals per group

Control animals:

yes

Examinations

Maternal examinations:

No data

Ovaries and uterine content:

No data

Fetal examinations:

- External examinations: Yes: [all per litter ]
- Soft tissue examinations: Yes: [half per litter]
- Skeletal examinations: Yes: [half per litter]

Statistics:

Chi-square analysis was performed. (it is worth noting that the experimental unit used for all statistical analyses was the individual fetus rather than the maternal unit)

Indices:

No data

Historical control data:

No data

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no data

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

100 mg/L drinking water

Basis for effect level:

other: no maternel effect toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

100 mg/L drinking water

Sex:

female

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Viability of fetuses:

Upon sacrifice of the dams, all fetuses were found to be viable and normal in external appearance.

Fetal weights:

Fetal weights per group were analyzed by a two-way analysis of variance. The 10 and 100 mg/l of monochloramine groups of male fetuses and the 1, 10 and 100 mg/l groups of female fetuses all showed an increased fetal weight compared with the control group, but these findings were not significantly different from the control.

Types of skeletal anomalies:

In monochloramie treatment, all groups (except 1 mg/l group for missing sternebrae) were quite similar to the control values.

The total defects after monochloramine treatment in drinking water:

The percentage of skeletal, soft-tissue and total defects (combined skeletal and soft-tissue) was calculated. With monochloramine, although the percentage of skeletal defects in the fetuses of 10 mg/l group (47.8 %) was higher than in the control (34.5 %), chi-square analysis revealed no significant difference. A slight increase in soft-tissue defects was found at all dose levels of monochloramine. The defects in all of these groups, including the control group, consisted of adrenal agenesis, dextrocardia and improper orientation of the apex of the heart. The 1 mg/l monochloramine group had one fetus with the right testicle missing. The percentage of total defects in all of the monochloramine groups was very similar to that of the control group. the experimental unit used for all statistical analyses was the individual fetus rather than the maternal unit.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this test, monochloramine did not produce teratogenic effects in rats.

Executive summary:

Female rats (6/group) were administered 0, 1, 10 and 100 mg/L of monochloramine daily in drinking water for 2 1/2 months prior to and throughout gestation. Female rats were sacrificed on Day 20 of gestation and fetus were examined for skeletal anomalies and other effects. Monochloramine did not produce any significant changes in rat fetuses at any dose level.