Paraquat-dichloride

Endpoint summary

Description of key information

- Oral: reported LD50 = 175 mg/kg bw, recalculated LD50 = 80.7 mg/kg bw; female; Sprague-Dawley rats; GLP compliant OECD 425; Pooles 2005.

- Inhalation: reported LC50 between 0.6 and 1.4 mg/m3 air, recalculated LD50 between 0.8 and 1.9 mg/m3 air; female and male; Wister rats; GLP compliant similar to OECD 403; McLean 1985.

- Dermal: reported LD50 >2000 mg/kg bw, recalculated LD50 >922 mg/kg bw; female and male; Sprague-Dawley; GLP compliant OECD 402; Pooles 2005.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 Jun 2005 to 23 Jul 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

Version / remarks:

17 December 2001

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Version / remarks:

2002

GLP compliance:

yes (incl. QA statement)

Remarks:

Safepharm Laboratories Limited, Shardlow Business Park Shardlow, Derbyshire, DE722GD UK

Test type:

up-and-down procedure

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 to 12 weeks
- Weight at study initiation: 207 to 253 g
- Fasting period before study: overnight fasting immediately before dosing and for approximately three to four hours after dosing
- Housing: individually housed in suspended solid-floor polypropylene cages furnished with woodflakes, animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level
- Diet: free access to food, Certified Rat and Mouse Diet (Code 5LF2)
- Water: free access to mains drinking water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25
- Humidity (%): 30 to 70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 5.5, 17.5, 55.0 mg/kg bw
- Amount of vehicle: 10 mL/kg

DOSING PROCEDURE
- The default value was entered into the AOT425 Statistical Program with the slope of the dose-response curve also set to the default value (sigma = 0.5). The statistical program gave a recommended dose progression of 2000, 550, 175, 55, 17.5, 5.5 and 1.75 mg/kg. The first animal was dosed at a dose level of 175 mg/kg. Further animals were then treated as follows: 55, 175, 550, 175 and 550 mg/kg bw for animals 2, 3, 4, 5 and 6, respectively.
- The test was complete after the sixth animal had been dosed as the following stopping criterion was met: at least four animals have followed the first reversal and the specified likelihood-ratios exceeded the initial value.
- Sufficient time (at least 48 hours) was allowed between each individual animal to confirm the survival of the previously dosed animals.

Doses:

55, 175, 550 mg/kg bw

No. of animals per sex per dose:

6 female animals in total (1 animal exposed to 55 mg/kg bw, 3 animals exposed to 175 mg/kg bw and 2 animals exposed to 550 mg/kg bw)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- The animals were observed for deaths or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for up to 14 days.
- Body weights were recorded prior to fasting (Day -1 ), prior to dosing (Day 0) and 7 and 14 days after treatment or at death.
- Necropsy of survivors performed: yes (external examination and opening of the abdominal and thoracic cavities for examination of major organs)

Statistics:

The oral LD50 was calculated by the maximum likelihood method

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

80.7 mg/kg bw

Based on:

test mat.

Remarks on result:

other: recalculated value, expressed as pure test substance, see ‘Any other information on results incl. tables’ for respective calculation.

Sex:

female

Dose descriptor:

LD50

Effect level:

175 mg/kg bw

Based on:

test mat.

95% CL:

> 42.8 - < 1 040

Remarks on result:

other: original value presented in study.

Mortality:

- At 55 mg/kg bw: 0 out of 1 animal died
- At 175 mg/kg bw: 1 out of 3 animals died
- At 550 mg/kg bw: 2 out of 2 animals died

Clinical signs:

other: Signs of systemic toxicity noted in one animal treated at a dose level of 175 mg/kg bw and one animal treated at a dose level of 550 mg/kg bw were hunched posture, pilo-erection, dehydration and pallor of the extremities. Additional signs of systemic toxi

Gross pathology:

Abnormalities noted at necropsy of animals that died during the study were haemorrhagic or abnormally red lungs, dark liver, dark kidneys, haemorrhage or epithelial sloughing of the gastric mucosa and non-glandular region of the stomach and haemorrhagic small intestine. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

Calculation of key result

The doses of the test substance were expressed in technical test substance, which relates to an aqueous solution of the registered substance. The key effect levels are calculated by correction for the amount of water: 33.4 % x 175 mg technical test substance/kg bw = 80.7 mg pure test substance/kg bw.

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

In this OECD 425 study, the test substance is classified in Acute Tox. 3 (H301: Toxic if swallowed) for acute toxicity via the oral route based on a LD50 of 80.7 mg/kg bw (original LD50 reported for technical test substance is 175 mg/kg bw).

Executive summary:

The GLP study was performed to assess the acute oral toxicity of the test material following a single oral administration in the Sprague-Dawley strain rat. The method was designed to meet the requirements of the following OECD 425. A total of 6 female animals were dosed individually in sequence with sufficient time (at least 48 hours) between each animal, at dose levels in the range of 55 mg/kg bw to 550 mg/kg bw. The test material was administered orally as a solution in distilled water. Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy.

Two animals treated at a dose level of 550 mg/kg bw were found dead three or six days after dosing. One animal treated at a dose level of 175 mg/kg bw of the test material was killed in extremis five days after dosing. No deaths were noted at a dose level of 55 mg/kg bw. Signs of systemic toxicity noted in one animal treated at a dose level of 175 mg/kg bw and one animal treated at a dose level of 550 mg/kg bw were hunched posture, pilo-erection, dehydration and pallor of the extremities. Additional signs of systemic toxicity noted in one animal treated at a dose level of 175 mg/kg bw were decreased respiratory rate, laboured or noisy respiration, lethargy, ptosis, ataxia, tiptoe gait, loss of righting reflex and emaciation. There were no signs of systemic toxicity noted in two animals treated at a dose level of 175 mg/kg bw and the animal treated at a dose level of 55 mg/kg bw. The surviving animals showed expected gains in body weight over the study period. Abnormalities noted at necropsy of animals that died during the study were haemorrhagic or abnormally red lungs, dark liver, dark kidneys, haemorrhage or epithelial sloughing of the gastric mucosa and non-glandular region of the stomach and haemorrhagic small intestine. No abnormalities were noted at necropsy of animals that were killed at the end of the study. The LD50 was determined to be 175 (42.89 – 1040) mg technical test substance/kg bw, although 2 out of 3 animals dosed at 175 mg/kg bw survived and showed no clinical signs of toxicity. The key effect resulting from the pure test substance is calculated based on the following calculation: Key effect level = purity of test material * effect level (LD50). It was determined to be 80.7 mg/kg bw.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

80.7 mg/kg bw

Quality of whole database:

GLP compliant, OECD 425.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Mar 1985 to 10 Apr 1985

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

traditional method

Limit test:

no

Species:

rat

Strain:

Wistar

Remarks:

Alpk:AP

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: ~7 weeks
- Weight at study initiation: males average 230 g (range: 208 to 244 g), females average 206 g (range: 192 to 223 g)
- Housing: Rats were housed five to a cage (sexes separately). Each cage had the following internal measurements: length 38.0 cm, width 32.5 cm and height 21.0 cm, and was suspended over a collecting tray lined with absorbent paper. The cages were contained in a single-sided mobile rat rack, and each cage was labelled with a stock card prior to exposure, and during the study by an experimental card, identifying the study, species, sex, animals and Home Office licensee.
- Diet: The animals were provided with food (pelleted Parton Combined Diet), ad libitum except during exposure.
- Water: water (via an automatic water system), ad libitum except during exposure.
- Acclimation period: 7 days prior to exposure.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 40 to 60
- Photoperiod (hours dark / hours light): 12 / 12

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

clean air

Mass median aerodynamic diameter (MMAD):

< 0.3 µm

Remark on MMAD/GSD:

>90% of the test aerosol for each treatment group had an aerodynamic equivalent diameter <0.3 µm

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only exposure using restraining tubes
- Exposure chamber volume: 18.4 L
- Source and rate of air: the flow rates, converted to normal temperature and pressure, were as follows:
* target concentration 0.2 mg/m3: 12.0 L/min generating air plus 15 L/min diluting air
* target 0.7 mg/m3: 16.5 L/min generating air plus 10 L/min diluting air
* target 1.5 mg/m3: 15.0 L/min generating air plus 10 L/min diluting air
*The control chamber was supplied with air at a rate of 12 L/min throughout exposure
- Method of conditioning air: dried and filtered through an atomiser and cyclone
- System of generating aerosols: Aerosols of the paraquat formulation were generated by passing clean, dry air through an atomiser and cyclone. For the 0.7 and 1.5 mg/m3 concentrations a 1% substance dilution was used. For the 0.2 mg/m3 a 0.1% substance dilution was used.
- Method of particle size determination: The aerodynamic particle size was measured once for each test group during the exposure period by means of a mini sampler which aerodynamically separates airborne particles into pre-determined size ranges. The major proportion (>84.5%) of the substance is present on stage 5 (aerodynamic equivalent diameter <0.3 µm).
- Temperature, humidity, pressure in air chamber: The temperature was 18 °C in all exposure chambers. Except for the top dose where it was 19 °C. The relative humidity was 27, 37, 38 and 41% in the control, 0.2, 0.7 and 1.5 mg/m3 groups, respectively.

TEST ATMOSPHERE
- Brief description of analytical method used: Nominal atmospheric concentration of active ingredient was calculated from the following formula after measuring, by weight loss, the amount of formulation used:


weight loss (mg) x % strength of final formulation x 1000
concentration (mg/m3) = -----------------------------------------------------------------------
Time (min) x Airflow (L/min) x 100


- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle: clean, dry air

Analytical verification of test atmosphere concentrations:

yes

Remarks:

The concentrations of active ingredient were calculated based on the weight loss of the formulation.

Duration of exposure:

4 h

Concentrations:

The concentrations of active ingredient from the weight loss of the formulation, were calculated to be as follows:
- theoretical concentration 0.2 mg/m3 test ion -> analytical concentration 0.20 ± 0.04 mg/m3 test ion
- theoretical concentration 0.7 mg/m3 test ion -> analytical concentration 0.60 ± 012 mg/m3 test ion
- theoretical concentration 1.5 mg/m3 test ion -> analytical concentration 1.4 ± 0.2 mg/m3 test ion

No. of animals per sex per dose:

5

Control animals:

yes

Remarks:

Clean dry air

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All rats were weighed on day -1 (defined as the day before exposure), prior to exposure on day 1 and then on days 2-8 and 15. The animals were also subjected to a detailed clinical examination on each day of the observation period and prior to post-mortem examination on day 15.
- Necropsy of survivors performed: yes, on day 15
- Other examinations performed: food consumption, gross pathology, organ weights (lungs, liver, kidneys and testes). Animals that died were also subjected to a post mortem examination.

Statistics:

Where appropriate, test and control data were compared statistically using a two-sided Student's t-test.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.6 - < 1.4 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: original value presented in study.

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.8 - < 1.9 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: recalculated value, expressed as pure test substance, see ‘Any other information on results incl. tables’ for respective calculation.

Mortality:

- There were no deaths in controls or test animals in the 0.20 or 0.60 mg/m3 groups during the exposure or observation periods.
- All animals in the 1.4 mg/m3 group survived the 4-hour exposure period, but the following deaths occurred during the observation period: 1 male (day 3); 2 males and 3 females (day 4); 1 female (day 5). The remaining 3 animals (2 males, 1 female) in this group were killed in extremis on day 6.

Clinical signs:

other: - During exposure: abnormalities normally associated with restraint (stains around the snout, chromodacryorrhea and wet fur) were seen in test and control groups. The severity of these effects was similar across the groups. - Immediately after exposure: a

Body weight:

Animals in all test and control groups lost weight following exposure. The effect was greatest in the top dose animals which continued to lose weight rapidly up to day 6 at which point the animals had either died or were killed in extremis. After the initial weight loss, the rate of weight gain in the 0.20 and 0.60 mg/m3 groups was similar to or greater than controls.

Gross pathology:

One male rat in the 0.20 mg/m3 group had dark red spots on the surfaces of all lobes of the lungs (this effect reduced after inflation with fixative) and froth exuded from the trachea during excision. No treatment related abnormalities were seen in any other animal in this group or in the 0.60 mg/m3 animals. Top dose animals had dark red, mottled lungs which were not fully deflated and several animals had froth exuding from the trachea.

Other findings:

- Organ weights: there were no statistically significant differences in the group mean organ weights or organ to last body weight ratios between animals in the 0.20 and 0.60 mg/m3 groups compared with controls. However, one male rat in the 0.2 mg/m3 group had a high lung weight (approximately 40% increase over the control value). The rats in the 1.4 mg/m3 group died or were killed in extremis before day 7 of the observation period and have therefore not been compared statistically with the controls. However, the data shows that there was a considerable increase in the lung weight of these animals (ratios increased by approximately 200-400%). There is also an apparent effect on the kidney with a low absolute value but high ratio to body weight. The apparently low liver-to-body weight-ratio and high testes-to-body weight-ratio are considered to result from the decreased body weight of these animals although glycogen depletion may have been a contributory factor in the liver.
- Other observations: There was a slight reduction in the food consumption of animals exposed to 1.4 mg/m3 between day 1 to 2 of the observation period with a pronounced reduction between day 2-6, i.e. after an apparent delayed effect of one day these animals ate very little food and then subsequently died or were killed in extremis before day 7. Food consumption of the controls and other test animals was similar throughout the study.

Calculation of key result

The doses of the test substance were expressed in test subtstance cation, which relates to the cation species in an aqueous solution of the registered substance. The effect levels are already corrected for the amount of water. The key effect levels are calculated by inclusion of the anion species:

(100/72.4) x 0.6 mg test substance cation / kg bw = 0.8 mg pure test substance/ kg bw.

(100/72.4) x 1.4 mg test substance cation / kg bw = 1.9 mg pure test substance/ kg bw.

Interpretation of results:

Category 1 based on GHS criteria

Conclusions:

Based upon the results obtained in this study the LC50 for the pure test substance (recalculated value) was determined to be between 0.8 and 1.9 mg/m3. This calculation was based on original effect levels of 0.6 and 1.4 mg/m3.

Executive summary:

The acute inhalation toxicity of the substance was assessed in a study design similar to OECD 403 and following GLP. In this study groups of five male and five female rats/ dose/ sex were exposed by nose-only exposure of to test atmosphere containing 0.20, 0.60 and 1.4 mg/m3 aerosol for a single 4-hour period. After exposure, the rats were kept for a 14-day observation period. 

Dose-related irritation of the respiratory tract and death at the top dose were observed. All animals in this top dose group survived the exposure period but died or were killed in extremis before day 7 of the observation period. There were no deaths at the lower dose levels. The clinical abnormalities seen indicated irritation of the respiratory tract at all dose levels with some indications of a dose-related increase in severity and general debility at the top dose level. There were significant associated reductions in body weight gain and food consumption only at the top dose level. Irritation of the respiratory tract persisted in a high proportion of test animals in the 0.20 and 0.60 mg/m3 groups during the first 7-10 days of the observation period but was not evident by day 15. In addition, there was a considerable increase in the lung weight of the top dose animals and macroscopic evidence of acute lung damage seen at post mortem examination of these animals.

The 4-hour LC50 of the formulation as tested was therefore between 0.60 and 1.4 mg/m3, which corresponds to a recalculated value of 0.8 to 1.4 mg/m3 pure substance.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

0.8 mg/m³ air

Quality of whole database:

GLP compliant, similar to 403.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Jun 2005 to 28 June 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

Adopted 24 February 1987

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

Commission Directive 92/69/EEC

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Version / remarks:

August 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Safepharm Laboratories Limited, Shardlow, Derbyshire, DE72 2GD, UK

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Remarks:

CD (Crl: CD (SD) IGS BR)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 to 12 weeks
- Weight at study initiation: at least 200 g, weight variations per sex < 20%
- Housing: the animals were housed in suspended solid-floor polypropylene cages furnished with woodflakes. The animals were housed individually throughout the study.
- Diet: ad libitum to Certified Rat and Mouse Diet (Code 5LF2)
- Water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25
- Humidity (%): 30 to 70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: shorn skin on the back and flanks of the animals
- % coverage: 10 (total body surface area)
- Type of wrap if used: surgical gauze semi-occluded with a piece of self-adhesive bandage

REMOVAL OF TEST SUBSTANCE
- Washing: 3% Teepol followed by warm water
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount applied: 2000 mg/kg
- Constant volume or concentration used: yes (1.77 mL/kg undiluted test substance)

Duration of exposure:

24 hours

Doses:

Dose level 2000 mg/kg

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: signs of toxicity: ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days. Body weight: individual body weights were recorded prior to application of the test material on day 0 (defined as day before exposure) and on days 7 and 14.
- Necropsy of survivors: At necropsy (after cervical dislocation) external examination and opening of the abdominal and thoracic cavities was performed.
- Other examinations performed: After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize.

Statistics:

Using the mortality data obtained, an estimate of the acute dermal median lethal dose (LD50) of the test material was made.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: original value presented in study

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 922 mg/kg bw

Based on:

test mat.

Remarks on result:

other: recalculated value, expressed as pure substance, see ‘any other information on results incl. tables’ for respective calculation

Mortality:

No mortality observed

Clinical signs:

other: No signs of systemic toxicity

Gross pathology:

No abnormalities were noted at necropsy

Other findings:

- Dermal Reactions: Very slight to well-defined erythema was noted at the treatment sites of three males and all females. Other signs of dermal irritation noted were haemorrhage of dermal capillaries, crust formation, small superficial scattered scabs and glossy skin. Skin reactions prevented evaluation of erythema and oedema at the treatment sites of two females during the study.

Calculation of key result

The doses of the test substance were expressed in technical paraquat dichloride, which relates to an aqueous solution of the registered substance. The key effect levels are calculated by correction for the amount of water: 0.461x 2000 mg paraquat dichloride technical material / kg bw = 922 mg pure paraquat dichloride / kg bw

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The LD50 for pure test substance (recalculated value) was determined to be >922 mg/kg body weight for males/females. This value is corresponding to a original value of > 2000 mg/kg bw technical solution.

Executive summary:

In this GLP compliance study performed according to OECD guideline 402, 5 female and 5 male rats (Sprague-Dawley CD) were exposed to the test substance at a concentration of 2000 mg/kg body weight for 24 hours under semi-occlusive conditions. After this period the test substance was removed with cotton wool moistened with 3% Teepol followed by warm water, and the animals were observed for a period of 14 days. No mortality and clinical signs were observed. Animals showed expected weight gains during the study and no abnormalities were observed at autopsy. Some mild skin reactions were noted including Very slight to well-defined erythema and haemorrhage of dermal capillaries, crust formation, small superficial scattered scabs and glossy skin. The LD50 was determined to be >2000 mg/kg body weight for males, females and sexes combined, which corresponds to a recalculated value of 922 mg pure substance/kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

922 mg/kg bw

Quality of whole database:

GLP compliant, OECD 402.

Additional information

Acute oral:

The GLP study was performed to assess the acute oral toxicity of the test material following a single oral administration in the Sprague-Dawley strain rat (Pooles 2005). The method was designed to meet the requirements of the OECD TG 425. A total of 6 female animals were dosed individually in sequence with sufficient time (at least 48 hours) between each animal, at dose levels in the range of 55 mg/kg bw to 550 mg/kg bw. The test material was administered orally as a solution in distilled water. Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy.

Two animals treated at a dose level of 550 mg/kg bw were found dead three or six days after dosing. One animal treated at a dose level of 175 mg/kg bw of the test material was killed in extremis five days after dosing. No deaths were noted at a dose level of 55 mg/kg bw. Signs of systemic toxicity noted in one animal treated at a dose level of 175 mg/kg bw and one animal treated at a dose level of 550 mg/kg bw were hunched posture, pilo-erection, dehydration and pallor of the extremities. Additional signs of systemic toxicity noted in one animal treated at a dose level of 175 mg/kg bw were decreased respiratory rate, laboured or noisy respiration, lethargy, ptosis, ataxia, tiptoe gait, loss of righting reflex and emaciation. There were no signs of systemic toxicity noted in two animals treated at a dose level of 175 mg/kg bw and the animal treated at a dose level of 55 mg/kg bw. The surviving animals showed expected gains in body weight over the study period. Abnormalities noted at necropsy of animals that died during the study were haemorrhagic or abnormally red lungs, dark liver, dark kidneys, haemorrhage or epithelial sloughing of the gastric mucosa and non-glandular region of the stomach and haemorrhagic small intestine. No abnormalities were noted at necropsy of animals that were killed at the end of the study. The LD50 was determined to be 175 (42.89 – 1040) mg technical test substance/kg bw, although 2 out of 3 animals dosed at 175 mg/kg bw survived and showed no clinical signs of toxicity. The key effect resulting from the pure test substance is calculated based on the following calculation: Key effect level = purity of test material * effect level (LD50). Thus, the oral LD50 value was determined to be 80.7 mg/kg bw.

Acute inhalation:

The acute inhalation toxicity of the substance was assessed in a study design similar to the requirements of OECD TG 403 and following GLP (McLean 1985). In this study groups of five male and five female rats/dose were exposed by nose-only exposure to test atmospheres containing 0.20, 0.60 and 1.4 mg/m3 aerosol for a single 4-hour period. After exposure, the rats were kept for a 14-day observation period.

Dose-related irritation of the respiratory tract and death at the top dose were observed. All animals in this top dose group survived the exposure period but died or were killed in extremis before day 7 of the observation period. There were no deaths at the lower dose levels. The clinical abnormalities seen indicated irritation of the respiratory tract at all dose levels with some indications of a dose-related increase in severity and general debility at the top dose level. There were significant associated reductions in body weight gain and food consumption only at the top dose level. Irritation of the respiratory tract persisted in a high proportion of test animals in the 0.20 and 0.60 mg/m3 groups during the first 7-10 days of the observation period, but was not evident by day 15. In addition, there was a considerable increase in the lung weight of the top dose animals and macroscopic evidence of acute lung damage seen at post mortem examination of these animals.

The 4-hour LC50 of the formulation as tested was therefore between 0.60 and 1.4 mg/m3, which corresponds to a recalculated value of 0.8 to 1.4 mg/m3 pure substance.

Acute dermal:

In this GLP compliant study performed according to OECD TG 402, 5 female and 5 male rats (Sprague-Dawley CD) were exposed cutaneously to the test substance at a concentration of 2000 mg/kg body weight for 24 hours under semi-occlusive conditions (Pooles 2005). After this period the test substance was removed with cotton wool moistened with 3% Teepol followed by warm water, and the animals were observed for a period of 14 days. No mortality and clinical signs were observed. Animals showed expected weight gains during the study and no abnormalities were observed at autopsy. Some mild skin reactions were noted including very slight to well-defined erythema and haemorrhage of dermal capillaries, crust formation, small superficial scattered scabs and glossy skin. The dermal LD50 was determined to be >2000 mg/kg body weight for males, females and sexes combined, which corresponds to a recalculated value of 922 mg pure substance/kg bw.

Justification for classification or non-classification

- Based on the available data on acute toxicity via the oral route, the substance is classified as Acute Tox. 3 (H301: Toxic if swallowed) according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. This classification is in line with the harmonised classification for this endpoint.

- Based on the available data on acute toxicity via the inhalation route, the substance is classified in Cat. 1 (H330: Fatal if inhaled) according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. This classification will be used instead of the harmonised classification (Cat. 2 (H330)) for this endpoint.

- Based on the respiratory irritation observed in the acute toxicity study for inhalation the substance is classified as STOT Single Exp. 3 (H335) according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

- Based on the available data on acute dermal toxicity, the substance is classified in Cat. 3 (H311: Toxic in contact with skin) according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. This classification is in line with the harmonised classification for this endpoint.