Registration Dossier

The acute inhalation toxicity of dimethyl sulphide was very low in rats. The 4-h LC50 was 40250 ppm (102 mg/L). Dimethyl sulphide, was found of low toxicity by oral and dermal routes in rats, with LD0s higher than 2000 mg/kg.

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France.
- Age at study initiation: 8 weeks old
- Weight at study initiation: 209-230 g
- Fasting period before study: overnight
- Housing: by three from the same group in polycarbonate cages
- Diet: SSNIFF R/M-H pelleted maintenance diet, ad libitum
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 50 ± 20
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 100 mg/ml
- Amount of vehicle (if gavage): 10 ml/kg

Doses:

2000 mg/kg bw

Control animals:

no

Details on study design:

CLINICAL EXAMINATIONS
Morbidity and mortality
Each animal was checked for mortality and morbidity, once a day during the acclimation period, frequently during the hours following administration, then once a day until the end of the observation period, including weekends.

linical signs
Each animal was observed after treatment as follows:
at least once during the first 30 minutes,
periodically during the first 4 hours,
then once a day, at approximately the same time, for the recording of clinical signs.
Any clinical signs observed were recorded individually for each animal, along with the times of onset and recovery.

Body weight
The body weight of each animal was recorded on the day of group allocation then on the day of treatment and on Days 8 and 15.
The body weight gain of the test item-treated animals was compared to that of CiToxLAB France historical control data generated from animals of the same strain and age treated with drinking water treated by reverse osmosis under similar experimental conditions.

PATHOLOGY
Euthanasia
On completion of the observation period, all animals were deeply anesthetized by an intraperitoneal injection of pentobarbital sodium and euthanized by exsanguination.

Macroscopic post-mortem examination
A macroscopic post-mortem examination was performed on all animals. After opening the thoracic and abdominal cavities, a macroscopic examination of the main organs (digestive tract, heart, kidneys, liver, lungs, pancreas, spleen and any other organs with obvious abnormalities) was performed. All gross observations were recorded individually for each animal.

Preservation of tissues
For all animals, the macroscopic lesions were preserved in 10% buffered formalin.
Any histological specimens (tissues in fixative) were destroyed at the finalization of the study report.

Microscopic examination
No microscopic examination was performed.

Statistics:

None

Sex:

female

Dose descriptor:

LD0

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No unscheduled deaths occurred during the study.

Clinical signs:

other: Piloerection was noted in 3/6 females on Day 1, associated with hunched posture in two of them.

Gross pathology:

The test item administration did not induce any macroscopic findings.
The macroscopic finding noted at necropsy (i.e. dilated uterus with translucent content in three females) is commonly recorded in the rat as a consequence of the estrous cycle (proestrus or estrus), and was therefore considered to be incidental.

The mean body weights and mean body weight changes (g) recorded in test item-treated animals during the observation period and in historical control data are summarized in the table below:

Sex	Female
Group	Historical control data	1	2
Dose-level (mg/kg)	0	2000	2000
Body weight (mean (± SD))
. Day 1	198 (± 6.6)	216 (± 6.1)	226 (± 3.5)
. Day 8	239 (± 8.6)	249 (± 11.0)	272 (± 12.7)
. Day 15	258 (± 8.6)	261 (± 6.1)	293 (± 21.4)
Body weight change (mean (± SD))
. Days 1-8	+41 (± 7.2)	+34 (± 7.0)	+46 (± 12.1)
. Days 8-15	+20 (± 6.7)	+11 (± 4.6)	+20 (± 9.0)
. Days 1-15	+60 (± 6.0)	+45 (± 3.8)	+66 (± 21.2)

SD: standard deviations.

Interpretation of results:

GHS criteria not met

Conclusions:

The oral LD0 of Dimethyl Sulfide was higher than 2000 mg/kg in rats.

Executive summary:

The potential acute toxicity of Dimethyl Sulphide, following a single oral administration (gavage) to rats was evaluated in astudy conducted in compliance with OECD Guideline No. 423. Dimethyl Sulphide in corn oil was administered once by oral route (gavage) at the dose level of 2000 mg/kg bw to two groups of three fasted female Sprague-Dawley rats under a dosage-volume of 10 mL/kg. After the first assay, as no toxicity was observed, the results were confirmed in other females. Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on Day 1 and then on Days 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted for a macroscopic post-mortem examination.

No unscheduled deaths occurred during the study. Piloerection was noted in 3/6 females on Day 1, associated with hunched posture in two of them. When compared to historical control data, a lower body weight gain was noted in 4/6 females over the whole study period (+41 to +48 g vs.+60 ± 6.0 g in control data base) including 1/6 females (+27 g vs.41 ± 7.2 g) between Day 1 and Day 8 and 1/6 females (+6 g vs. +20 ± 6.7 g) between Day 8 and Day 15. The body weight gain of the other animals was unaffected by the treatment. No macroscopic findings were observed. The oral LD₀of Dimethyl Sulfide was higher than 2000 mg/kg in rats.

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Reference

Endpoint:: acute toxicity: inhalation
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 (similar to OECD test guideline 403), acceptable for assessment
Qualifier:: equivalent or similar to guideline
Guideline:: OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:: no
GLP compliance:: not specified
Test type:: standard acute method
Limit test:: no
Species:: rat
Strain:: Sprague-Dawley
Sex:: male/female
Details on test animals or test system and environmental conditions:: TEST ANIMALS
- Source: Charles River
- Age at study initiation: adult males and females
- Weight at study initiation: 90 - 100 g on day of receipt
- Fasting period before study: data not available
- Housing: 5 per cage (except during exposure, where males and females were combined)
- Diet: pelleted Purina Laboratory Chow, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22°C
- Humidity (%): data not available
- Air changes (per hr): data not available
- Photoperiod: constant light cycles (no other information available)

IN-LIFE DATES: data not available
Route of administration:: inhalation: vapour
Type of inhalation exposure:: whole body
Vehicle:: clean air
Details on inhalation exposure:: GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Test substance is fed into the exposure chamber through inlet port and exhausted through tube. Gaseous effluent is passed through a filtering system before evacuation into the inside atmosphere. Gas mixture is pulled through the chamber by vacuum pump and the slightly negative chamber pressure is monitored by mercury manometer. Chamber temperature is monitored by thermonmeter.

Configuration of apparatus used to vaporize dimethyl sulfide: the liquid compound is pumped at a fixed rate from the syringe pump into the vaporization chamber, heated by the electric mantle via the variable transformer, where it vaporizes almost instantaneously. Room air is metered through the vaporization chamber by the flowmeter. The resulting mixture is further mixed with the main stream of room air monitored by flowmeter. The major portion of room air passing through the exposure chamber does not pass through the vaporization flask to prevent overheating of the exposure chamber. The resultant air-vapor mixture is drawn through the exposure chamber by a vacuum pump connected to the exhaust tube.

ANIMAL EXPOSURE
Each dose group consisted of 5 male and 5 female rats, which were combined for a 4-h exposure or sham exposure to air in a customized 75-l glass chamber and then separated for observation over the subsequent 14-day period. The rats were deprived of food and water during actual exposure or sham exposure.
Analytical verification of test atmosphere concentrations:: not specified
Duration of exposure:: 4 h
Concentrations:: 0, 800, 3000, 6000, 12000, 24000, 36000, 39000, 42000, 45000, 48000 ppm
(approximately 0, 2.03, 7.61, 15.2, 30.4, 60.9, 91.3, 98.9, 106, 114, or 122 g/L)
No. of animals per sex per dose:: 5 males and 5 females per group
Control animals:: yes
Details on study design:: Animals from any group that died during the 14-day period were examined for gross pathology, such as general or local haemorrhage and adhesions, and the survivors were sacrificed and examined as well. Mortality and such visually apparent behaviour as exploring, huddling, preening, and obvious distress were noted during the course of the 4-hour exposure and sham exposure.
Statistics:: LC50 values and 95% confidence limits were estimated by the classical method of Litchfield and Wilcoxon (1949)
Sex:: male/female
Dose descriptor:: LC50
Effect level:: 40 250 ppm
95% CL:: 38 018 - 42 613
Exp. duration:: 4 h
Remarks on result:: other: # 102 g/m3
Mortality:: Any animal that survived the first 24 h after exposure survived to the end of the 2-wk observational period.
See table 1 below.
Clinical signs:: other: data not available
Body weight:: data not available
Gross pathology:: There was no evidence of external bleeding from any orifice in rats that succumbed or survived
Interpretation of results:: GHS criteria not met
Conclusions:: The 4-h inhalation LC50 in rats of dimethyl sulfide is 40250 ppm (# 102 g/m3).
Executive summary:: Five rats per sex per group were exposed for 4 hours to dimethyl sulfide vapor at 0, 800, 3000, 6000, 12000, 24000, 36000, 39000, 42000, 45000, or 48000 ppm (approximately 0, 2.03, 7.61, 15.2, 30.4, 60.9, 91.3, 98.9, 106, 114, or 122 mg/L). The LC₅₀ was 40250 ppm (102 mg/L) with a 95% confidence interval of 38018-42613 ppm (96.6 mg/L to 108.3 mg/L). Animals were observed for 14 days following the exposure. No data for clinical signs or body weight effects, were provided in the report. Mortality was observed for some animals in all groups exposed to concentrations equal to or greater than 36000 ppm. At necropsy, there was no evidence of external bleeding from any orifice in rats that succumbed or survived.

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

102 000 mg/m³ air

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLp guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France.
- Age at study initiation: 8 weeks old
- Weight at study initiation: 338 g (range: 326 g to 354 g) for males and 244 g (range: 230 g to 258 g) for females
- Housing: by 5 from the same group in polycarbonate cages
- Diet: SSNIFF R/M-H pelleted maintenance diet, ad libitum
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 50 ± 20
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: back, approximately 7 cm x 5 cm for males and 6 cm x 5 cm for females
- % coverage: ca. 10
- Type of wrap if used: aerated hypoallergenic dressing

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

CLINICAL EXAMINATIONS
Morbidity and mortality
Each animal was checked for mortality and morbidity, once a day during the acclimation period, frequently during the hours following administration, then once a day until the end of the observation period, including weekends.

linical signs
Each animal was observed after treatment as follows:
at least once during the first 30 minutes,
periodically during the first 4 hours,
then once a day, at approximately the same time, for the recording of clinical signs.
Any clinical signs observed were recorded individually for each animal, along with the times of onset and recovery.

Body weight
The body weight of each animal was recorded on the day of group allocation then on the day of treatment and on Days 8 and 15.
The body weight gain of the test item-treated animals was compared to that of CiToxLAB France historical control data generated from animals of the same strain and age treated with drinking water treated by reverse osmosis under similar experimental conditions.

PATHOLOGY
Euthanasia
On completion of the observation period, all animals were deeply anesthetized by an intraperitoneal injection of pentobarbital sodium and euthanized by exsanguination.

Macroscopic post-mortem examination
A macroscopic post-mortem examination was performed on all animals. After opening the thoracic and abdominal cavities, a macroscopic examination of the main organs (digestive tract, heart, kidneys, liver, lungs, pancreas, spleen and any other organs with obvious abnormalities) was performed. All gross observations were recorded individually for each animal.

Preservation of tissues
For all animals, the macroscopic lesions were preserved in 10% buffered formalin.
Any histological specimens (tissues in fixative) were destroyed at the finalization of the study report.

Microscopic examination
No microscopic examination was performed.

Statistics:

None

Sex:

male/female

Dose descriptor:

LD0

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No unscheduled deaths occurred during the study.

Clinical signs:

other: No clinical signs indicative of systemic toxicity were observed in any animals. A very slight or well-defined erythema was noted at the application site in all females from Day 2 or 3 until Days 5, 8 or 12 and 1/5 males from Day 4 to Day 10, associated wi

Gross pathology:

No macroscopic findings that could be related to treatment were observed in males and females.
2/5 females (animals D28132 and D28133) presented a bilateral dilation of the uterine horns with a translucent content, which was consistent with a physiologic pro-estrus or early estrus state in these female rats.
The gross findings observed were of those commonly reported in the rat of this strain and age and therefore a relationship to treatment was excluded.

The mean body weights and the mean body weight changes (g) recorded in test item-treated animals during the observation period and in CiToxLABhistorical control data are summarized in the table below:

Sex	Female		Male
Group	CiToxLAB France historical control data	1	CiToxLAB France historical control data	2
Dose-level (mg/kg)	0	2000	0	2000
Body weight (mean (± SD))
. Day 1	228 (± 8.5)	244 (± 10.5)	379 (± 15.1)	338 (± 12.8)
. Day 8	253 (± 13.5)	273 (± 15.1)	410 (± 16.7)	373 (± 16.6)
. Day 15	270 (± 13.5)	303 (± 10.2)	422 (± 22.6)	418 (± 21.4)
Body weight change (mean (± SD))
. Days 1-8	+25 (± 9.5)	28 (± 7.3)	+30 (± 9.3)	35 (± 6.6)
. Days 8-15	+17 (± 7.1)	30 (± 6.4)	+33 (± 11.5)	45 (± 5.8)
. Days 1-15	+41 (± 9.6)	59 (± 7.5)	+63 (± 12.2)	80 (± 11.5)

SD: Standard Deviations.

Interpretation of results:

GHS criteria not met

Conclusions:

The dermal LD0 of Dimethyl Sulphide was higher than 2000 mg/kg in rats.

Executive summary:

The potential toxicity of Dimethyl Sulphide following a single dermal application to rats was evaluated in a study conducted in compliance with OECD Guideline No. 402. Dimethyl Sulphide was applied in its original form to the skin of five female then five male Sprague-Dawley rats at the dose-level of 2000 mg/kg. The application site was covered by a semi-occlusive dressing for 24 hours.

Each animal was observed at least once a day for mortality and clinical signs for 15 days. From Day 2, any local reactions at the treatment site were also noted. Body weight was recorded before allocation into group, then on Days 1, 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted for a macroscopic post-mortem examination. No microscopic examination was performed.

No unscheduled deaths occurred during the study. No clinical signs indicative of systemic toxicity were observed in any animals. A very slight or well-defined erythema was noted at the application site in all females from Day 2 or 3 until Days 5, 8 or 12 and 1/5 males from Day 4 to Day 10, associated with scabs in 2/5 females and the male. Body weight of animals was unaffected by the test item treatment.

No treatment-related macroscopic findings were observed. The dermal LD₀o Dimethyl Sulphide was higher than 2000 mg/kg in rats.

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Acute oral toxicity

The potential acute toxicity of Dimethyl Sulphide, following a single oral administration (gavage) to rats was evaluated in a study conducted in compliance with OECD Guideline No. 423 (Silvano, 2015a). Dimethyl Sulphide in corn oil was administered once by oral route (gavage) at the dose level of 2000 mg/kg bw to two groups of three fasted female Sprague-Dawley rats under a dosage-volume of 10 mL/kg. After the first assay, as no toxicity was observed, the results were confirmed in other females. Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on Day 1 and then on Days 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted for a macroscopic post-mortem examination. No unscheduled deaths occurred during the study. Piloerection was noted in 3/6 females on Day 1, associated with hunched posture in two of them. When compared to historical control data, a lower body weight gain was noted in 4/6 females over the whole study period (+41 to +48 g vs. +60 ± 6.0 g in control data base) including 1/6 females (+27 g vs.41 ± 7.2 g) between Day 1 and Day 8 and 1/6 females (+6 g vs. +20 ± 6.7 g) between Day 8 and Day 15. The body weight gain of the other animals was unaffected by the treatment. No macroscopic findings were observed. The oral LD₅₀of Dimethyl Sulfide was higher than 2000 mg/kg in rats.

Acute inhalation toxicity

In rats, the 4h LC₅₀of dimethyl sulphide was 40250 ppm (102 mg/L) (similar to testing guideline OECD 403). No data for clinical signs or body weight effects, were provided in the report. Mortality was observed for some animals in all groups exposed to concentrations equal to or greater than 36000 ppm. At necropsy, there was no evidence of external bleeding from any orifice in rats that succumbed or survived (Tansy et al., 1981).

Five mice (sex not specified) were exposed to static atmospheres of dimethyl sulphide vapor of 6.8, 11.6, 23.6, 34.0, or 50.6 volume % (68000, 116000, 236000, 340000, or 506000 ppm). All animals died within approximately 8 minutes at 6.8% (approximately 173 mg/L). Animals exposed to 50.6% died within one minute; cause of death was possibly due to asphyxiation (Terazawa et al., 1991).

Acute dermal toxicity

The potential toxicity of Dimethyl Sulphide following a single dermal application to rats was evaluated in a study conducted in compliance with OECD Guideline No. 402 (Silvano, 2015b). Dimethyl Sulphide was applied in its original form to the skin of five female then five male Sprague-Dawley rats at the dose-level of 2000 mg/kg. The application site was covered by a semi-occlusive dressing for 24 hours. Each animal was observed at least once a day for mortality and clinical signs for 15 days. From Day 2, any local reactions at the treatment site were also noted. Body weight was recorded before allocation into group, then on Days 1, 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted for a macroscopic post-mortem examination. No microscopic examination was performed. No unscheduled deaths occurred during the study. No clinical signs indicative of systemic toxicity were observed in any animals. A very slight or well-defined erythema was noted at the application site in all females from Day 2 or 3 until Days 5, 8 or 12 and 1/5 males from Day 4 to Day 10, associated with scabs in 2/5 females and the male. Body weight of animals was unaffected by the test item treatment. No treatment-related macroscopic findings were observed. The dermal LD₀of Dimethyl Sulphide was higher than 2000 mg/kg in rats.

According to the results obtained with dimethyl sulphide and the criteria of Regulation (EC) No 1272/2008:

Acute oral toxicity: (rat) LD₀> 2000 mg/kg bw: no classification is required

Acute inhalation toxicity: 4h LC₅₀(rat) = 102 mg/L: no classification is required

Acute dermal toxicity: (rat) LD₀> 2000 mg/kg bw (no mortality): no classification is required

Dose (ppm)	Mortality
Sham	0 / 10
800	0 / 10
3000	0 / 10
6000	0 / 10
12000	0 / 10
24000	0 / 10
36000	2 / 10
39000	5 / 10
42000	5 / 10
45000	8 / 10
48000	9 / 10