Mecoprop

Endpoint summary

Description of key information

Acute Oral Toxicity Key Study: Kirsch (1983)

Under the conditions of this study, the acute oral LD50 of the test material was 1 166 mg/kg.

 

Acute Inhalation Toxicity Key Study: Klimisch (1986)

Under the conditions of this study, the acute inhalation LC50 (4 h) of the test material was found to be >12.5 mg/L.

Acute Inhalation Toxicity Supporting Study: Coombs (1977)

Under the conditions of this study it was not possible to generate the dust of the test material above a mean level of 0.02 g/m^3.

It was found to be difficult to generate a significant level of dust of the test material due to the cohesive nature of the material. It is expected that the test material is unlikely to produce any appreciable level of respirable dust under normal handling conditions.

Acute Dermal Toxicity Key Study: Kirsch (1983)

Under the conditions of this study, the acute dermal LD50 of the test material to rats was > 4 000 mg/kg.

 

Acute Intraperitoneal Toxicity Supporting Study: Kirsch (1988)

Under the conditions of this study, the acute LD50 after a single intraperitoneal administration of test material in male and female rats was found to be > 200 < 700 mg/kg.

 

Acute Intraperitoneal Toxicity Supporting Study: Kirsch (1983)

Under the conditions of this study, the acute LD50 after a single intraperitoneal administration of test material in male and female rats was approximately 464 mg/kg bw.

 

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:

03 November 1982 to 11 January 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

no

Remarks:

Study pre-dates GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Fasting period before study: Animals were given no feed 16 hours before administration, but water was available ad libitum.
- Housing: Animals were housed in stainless steel wire mesh cages. 5 animals per cage.
- Water: Tap water available ad libitum
- Acclimation period: At least one week

ENVIRONMENTAL CONDITIONS
- Temperature: 20 - 24 °C
- Humidity: 30 - 70 %
- Photoperiod: 12 Hours dark/12 Hours light (06.00 - 18.00 hours/ 18.00 - 06.00 hours)

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

(0.5 % aqueous)

Details on oral exposure:

TEST MATERIAL:
- Vehicle: 0.5 % aqueous carboxymethyl cellulose forming a suspension with the test material.
- Amount applied: 10 mL/kg
- Concentration: 6.81 % w/v (681 mg/kg), 10.00 % w/v (1000mg/kg), 14.70 % w/v (14.70 mg/kg), 21.50 % w/v (2150 mg/kg)

Doses:

681, 1000, 1470, 2150 mg/kg

No. of animals per sex per dose:

5 males and 5 females per dose.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Recording of signs and symptoms several times on the day of administration, at least once each workday. Checks for moribund and dead animals twice each workday and once on holidays.
- Necropsy of survivors performed: yes, withdrawal of food 16 hours before sacrifice with CO2; then necropsy with gross-pathological examination performed.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

1 166 mg/kg bw

Based on:

test mat.

95% CL:

>= 1 004 - <= 1 362

Mortality:

Mortality was observed at dose levels 1000, 1470 and 2150 mg/kg in both female and male animals. At dose 1000 mg/kg, 2/10 animals had died by day 14, at dose 1470 mg/kg 9/10 animals had died by day 14 and at dose 2150 mg/kg 9/10 animals had died by day 14.

Clinical signs:

other: No abnormalities were observed at dose level 681 mg/kg during the observation period. At the higher dose levels, a wide range of symptoms were observed for both female and male animals, these include: Dyspnea, apathy, abnormal positioning, staggering, ato

Gross pathology:

Animals that died:
- General congestion.
- Stomach: bloody ulcerations in the glandular stomach in some animals; injected vessels.
- Intestines: Slightly atonic and contents mixed with blood in some animals.
- Urinary bladder: Strikingly filled in some animals.

Sacrificed animals:
- One animal (2150 mg/kg): Tip of the forestomach thickened; adhesions of the forestomach to the peritoneum and liver.
Remaining animals:
- Organs: no abnormalities detected.

Mortality During the Study

Dose (mg/kg)		2150	1470	1000	681
Males
Number of Animals		5	5	5	5
Number of Dead Animals After:	1 h	0	0	0	0
	1 d	0	0	0	0
	2 d	4	3	1	0
	7 d	4	5	1	0
	14 d	4	5	1	0
Females
Number of Animals		5	5	5	5
Number of Dead Animals After:	1 h	0	0	0	0
	1 d	2	2	0	0
	2 d	5	4	1	0
	7 d	5	4	1	0
	14 d	5	4	1	0

Interpretation of results:

other: EU Category 4, H302 Harmful if swallowed

Conclusions:

Under the conditions of this study, the acute oral LD50 of the test material was 1166 mg/kg for males and females.

Executive summary:

The acute oral toxicity of the test material was investigated in a study similar in design to OECD 401.

Five male and five female Wistar rats were treated orally with the test material at doses of: 681, 1000, 1470 and 2150 mg/kg in a single administration by gavage. The animals were observed for 14 days, before gross necropsy was performed.

Mortality and clinical abnormalities were observed at dose levels 1000, 1470 and 2150 mg/kg, body weights increased during the observation period at all doses. In the animals that died, the gross pathology found abnormalities such as stomach ulcers, slightly atonic intestines and strikingly filled bladders in some animals. In the sacrificed animal, tip of the forestomach thickened. In the remaining animals, no abnormalities were observed.

Under the conditions of this study, the acute oral LD50 of the test material was 1166 mg/kg.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

1 166 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 August 1986 to 30 September 1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Approximately 8 - 9 weeks.
- Weight at study initiation (mean ± s.d.): Male: 284 ± 19.8 g, female: 189 ± 14.2 g.
- Housing: Animals were housed in groups of five (test groups 1 and 2 and the male rats animal number 1 - 5 of the test group 3); from day 2 onward the male animals, animal number 6 - 10 of the test group 3 were housed singly (indications of not substance related aggressivity) in cages type D III of Becker, without bedding.
- Diet: Ad libitum during the post-exposure observation period
- Water: Ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature: 20 to 24 °C
- Humidity: 30 to 70 % relative humidity
- Photoperiod: 12 hours light/ 12 hours dark

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose/head only

Vehicle:

other: The test material was milled and mixed with 1 wt % of Aerosil to achieve a more uniform dust concentration in air.

Mass median aerodynamic diameter (MMAD):

5.6 µm

Geometric standard deviation (GSD):

2.3

Remark on MMAD/GSD:

Test group 1

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Head-nose inhalation system INA 20 (glass-steel construction, BASF. Aktiengesellschaft, volume V ~ 55 1) : the animals were restrained in tubes and their snouts projected into the inhalation chamber.
-Generation on inhalation atmosphere: A dust air mixture was generated by means of a vibration dust partitioning equipment (BASF). The test material was milled and mixed with 1 wt % of Aerosil in order to achieve a more uniform dust concentration in air. The concentration was adjusted by varying the apertural width and by varying the amplitude of oscillations of the metering beaker.
- The following air flows were set: 1500 l/h compressed air through the injector and 1500 l/h conditioned air as dilution air. The supply air was conditioned via a central air-conditioning system in such a way that there was a temperature of 19 - 25 °c in the exposure apparatus. Deviations from this specification which would have had any adverse effect on the results of the study did not occur.
-The inhalation mixture was offered to the animals for inhalation for 4 hours.
-By means of an exhaust air system the pressure ratios in the inhalation system were adjusted in such a way that the amount of exhaust air was about 10 % lower (excess pressure). This ensured that the mixture of test material and air was not diluted with laboratory air in the breathing zones of the animals.

TEST ATMOSPHERE
- Nominal concentration: The nominal concentration was calculated from the amount of test material -1 wt % excipient and the air flow.
- Sampling apparatus:
Vacuum compressed air pump: (Millipore) XX 60 220 50
Filtration equipment with probe (Millipore) (internal diameter: 4 mm)
Filter: MN 85/90 Bf (d = 4.7 cm)
Sampling velocity: 1.25 m/s
Sampling amount: 11 - 21
Sampling position: immediately adjacent to the animals’ noses
Sampling frequency: 1 sample about hourly for test group 3, and 1 sample about every 30 minutes for the test groups 1 and 2.
- Analytical determination method: Gravimetric determination of the inhalation atmosphere concentration
Equipment: balance: Mettler HL 52
The pre-weighed filter was placed into the filtration equipment. By means of a vacuum compressed air pump a volume of the dust aerosol was drawn through the filter. The dust concentration in mg/L was calculated from the difference between the pre-weight of the filter and the weight of the filter after sampling, with reference to the sample volume of the inhalation atmosphere. The concentrations were corrected for the amount of the added excipient.

- Particle size analysis:
Equipment:
- Andersen Stack Sampler Hark III
- Millipore Vacuum Compressed Air Pump XX 60 220 50
- Sampling probe (internal diameter 6.9 mm)
- Stopwatch
Procedure:
30 minutes after the beginning of the test at the earliest, one sample was taken per test group for the particle size analysis.
Before the sampling, the impactor was equipped with glass-fiber collecting discs and a backup particle filter. The impactor was connected to the pump and the test apparatus, and one sample (3 - 9 L) was taken. The impactor was taken apart, the collecting discs and the backup particle filter were weighed.
The contents of the pre-impactor as well as the amounts of the material adsorbed on the walls of the impactor and in the sampling probe (wall losses) were also determined quantitatively.


RESULTS OF ANALYTICAL MEASUREMENTS
Concentration measurements: Each individual sample was analysed. The following are summaries of the results per group:
-Test group 1:
Mean uncorrected: 12.6 mg/L
Mean corrected for excipient: 12.5 mg/L
Standard deviation of the mean: ± 2.32 mg/L
Nominal concentration: 42.9 mg/L

-Test group 2:
Mean uncorrected: 9.6 mg/L
Mean corrected for excipient: 9.5 mg/L
Standard deviation of the mean: ± 1.27 mg/L
Nominal concentration: 28.0 mg/L

-Test group 3:
Mean uncorrected: 5.5 mg/L
Mean corrected for excipient: 5.4 mg/L
Standard deviation of the mean: ± 1.36 mg/L
Nominal concentration: 10.5 mg/L


RESULTS OF PARTICLE SIZE ANALYSES
- Test group 1:
MMAD 50%: 5.6 µm (geometric standard deviation = 2.3)
Respirable dust fraction that might reach alveoli of: 83 %.

- Test group 2:
MMAD 50%: 6.2 µm (geometric standard deviation = 2.3)
Respirable dust fraction that might reach alveoli of: 77 %.

- Test group 3:
MMAD 50%: 4.1 µm (geometric standard deviation = 2.3)
Respirable dust fraction that might reach alveoli of: 91 %.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.4, 9.5 and 12.5 mg/L.
The selection of the concentration for test group 3 was based on the limit test, OECD Test Guidelin 403. The other concentrations were selected in order to achieve an estimation of the LD50.

No. of animals per sex per dose:

10 animals per sex per dose

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The body weight of the animals was checked before the beginning of the test, after 7 days and at the end of the observation period. Clinical findings were recorded several times during exposure and at least once on each workday in the observation period. A check for dead animals was made daily.
- Necropsy of survivors performed: yes, at the end of the 14-day observation period the surviving animals were sacrificed with CO2 and were subjected to gross-pathological examination like all other animals which had died before. To clarify the gross pathological findings selected organs of individual animals were examined histopathologically.

Statistics:

The statistical evaluation of the test was carried out in accordance with a probit analysis of D.J. Finney (0.J. Finney; Probit Analysis 1971, pp. 1 - 150. Published by the Syndics of the Cambridge University Press, Bentley House, 200 Euston Road, London N.W.1.).
The particle size was determined in the Department of Toxicology of BASF Aktiengesellschaft on the basis of mathematical methods for evaluating particle measurements (Silverman, L.: Particle Size Analysis in Industrial Hygiene, 1971, pp. 235 - 259).

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 12.5 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: maximum achievable concentration tested.

Mortality:

Test group 1 (12.5 mg/L): 5/20 animals had died by day 14.
Test group 2 (9.5 mg/L): 4/20 animals had died by day 14.
Test group 3 (5.4 mg/L): 3/20 animals had died by day 14.

Clinical signs:

irregular respiration

Body weight:

A significant retarded body weight gain of female and male rats of all test groups compared with a historical control collective was observed.

Gross pathology:

Animals that died spontaneously (males and females):
5.4 mg/L: General congestion, Lung - slight oedematisation.
9.5 mg/L: General congestion
12.5 mg/L: Lung: some slightly sunken darker areas, with irregular margins.

Sacrificed animals (males and females):
- Organs: No abnormalities detected.
- Microscopic findings: 12.5 mg/L: One male animal that died - Beginning focal Bronchopneumonia.

Clinical Signs

- During exposure: single attempts to escape; irregular to jerky respiration; reddish nasal discharge (blood test positive).

- After exposure: irregular to jerky respiration; sounds of respiration; unsteady gait: noses partly with reddish smear or encrustations; reduced state of health: apathy; some male rats showed aggressivity (only test group 3).

- As of day 7 of the observation period, for the test group 1 and 3: day 12 for the test group 2 no abnormalities were detected in the animals.

 

Mortality in the Study

Cumulated Lethality on Day	Test Group (Concentration)
	1 (12.5 mg/L)		2 (9.5 mg/L)		3 (5.4 mg/L)
	M	F	M	F	M	F
0	2/10	0/10	2/10	2/10	2/10	1/10
1	3/10	2/10	-	-	-	-
2	-	-	-	-	-	-
7	-	-	-	-	-	-
14	-	-	-	-	-	-
Total at end of the study	5/20		4/20		3/20

M = Male, F = female

- = Lethality unchanged

0 = Day of exposure

 

Body Weight

Mean Body Weight		Before the Study		After 7 Days		After 14 Days
		Male	Female	Male	Female	Male	Female
Test group 1	Weight in g	300	203	313	213	337	217
	No. of animals	10	10	7	8	7	8
Test group 2	Weight in g	261	177	268	184	304	196
	No. of animals	10	10	8	8	8	8
Test group 3	Weight in g	292	187	291	195	328	206
	No. of animals	10	10	8	9	8	9
Historical (air) control	Weight in g	248	177	285	196	317	210

 

Interpretation of results:

other: Not classified according to EU criteria

Conclusions:

Under the conditions of this study, the acute inhalation LC50 (4 h) of the test material was found to be >12.5 mg/L.

Executive summary:

The acute inhalation toxicity of the test material was investigated in a study design based on the OECD 403 guideline. The study was conducted under with GLP conditions.

10 male and 10 female Wistar rats per group were exposed to concentrations of 5.4, 9.5 and 12.5 mg/L of the active ingredient for a period of 4 hours.

During the exposure the following clinical signs were observed: single attempts to escape, irregular to jerky respiration, reddish nasal discharge. After the exposure irregular to jerky respiration, sounds of respiration, unsteady gait, noses partly with reddish smear or encrustations, reduced state of health and apathy were observed. In animals that died during the exposure period general congestion, slight oedematisation and some slightly sunken darker areas at the lung were found. In sacrificed animals no abnormalities were observed.

Under the conditions of this study, the acute inhalation LC50 (4 h) of the test material was found to be >12.5 mg/L.

Reference 2

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Albino rats were whole body exposed to the test material via inhalation for 4 hours and observed for 14 days.

GLP compliance:

no

Remarks:

This study pre-dates the inception of GLP.

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Remarks:

CD Strain (a Caesarian derived strain of Sprague-Dawley origin).

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: Mean male weight: 238 g, mean female weight: 198 g
- Housing: The animals were housed in polypropylene wire bottomed cages, suspended on a mobile rack. Each cage held 7 rats of like sex.
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: Prior to exposure the animals were kept for a minimum of 3 days in a holding room.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2 °C
- Humidity: relative humidity 55 to 70 %

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- The dust was produced using a Wright Dust generator (Wright, B. M., 1950 Journal of Scientific Instruments, 27, 12). In this electrically operated device, a scraper blade removes the powder from a pre-packed canister. The powder is removed at a steady rate which is determined by selection of different gear ratios on the generator. Dry compressed air passed into the canister along a groove cut in the scraper blade, blows out the loose powder as it is scraped off, after passing through a jet and impinging on a baffle plate (to break up any aggregates), the air containing the powder finely -dispersed, passes via an inlet column (3 cm in diameter; 25 cm in length) into the exposure chamber. The exposure chamber is constructed from 0.63 cm thick Perspex sheet. The internal volume of the chamber is approximately 100 litres. Galvanised metal grilles divided each chamber into 8 separate compartments, into which the animals are placed immediately prior to exposure. Each chamber is of square section and fitted with a pyramidal top.
- A sample of the test material was ground in a pestle and mortar for 10 minutes, prior to packing of the canister. A portion of the test material was packed into a canister of a Wright dust generator with the aid of a hydraulic bench press (0.2 ton pressure). Packing was accomplished in stages to ensure an even density within the canisters. Each canister was then placed in position on a Wright dust generator mounted on a stand below the inlet column, connecting with a central hole at the base of an exposure chamber. The exit nozzle of each dust generator passed through a rubber diaphragm covering the end of the column nearest the dust generator. The diaphragm formed an airtight seal around the exit nozzle of the dust generator and contained the dust within the column until it passed into the exposure chamber. As the dust passed up this column the velocity of the air flow was reduced so that the larger particles deposited out within the column and only the smaller particles passed into the exposure chamber. The animals were then placed within the compartments of the exposure chambers and the position of each individual animal was noted. The flow of compressed air through each generator was regulated at 20 L/minute prior to packing of the canister.
- Each exposure was started by disengaging the gears on the Wright dust generator and manually advancing the loaded canister up onto the scraper blade until a trace of dust was seen to emerge into the chamber. The gears were then re-engaged and the mechanism switched on. The gear ratio used to generate the dust of the test material was 1: 1. The dust dispersed evenly throughout each chamber, and exited through a series of small holes drilled below animal level around the base of each chamber. The chambers were positioned inside larger glass walled extraction chambers, approximately 1 m^3 in volume. Each extraction chamber was equipped with an externally sited extract fan venting to the atmosphere through a collecting filter. The dust emerging from the holes around the base of the chamber was drawn off as it emerged. The dust of both samples was generated continuously throughout the four hour exposure period.
- The conditions under which exposure of the control group took place were identical to those used for the exposure of the test material with the exception that an empty canister was placed on the generator.

TEST ATMOSPHERE
- Estimation of the dust concentration within the chamber: Samples were taken during exposure in order to estimate the total atmosphere concentration of the test material. A total of 5 samples were withdrawn from the atmosphere generated of the dust of the test material during each of the 4 hour exposure periods. A gravimetric method was used employing an open face filter collection system. For each sample a pressed glass fibre filter (Whatman GF/A-3.7 cm diameter) was placed in a filter holder. The total area of exposed filter available for collection was 7 cm^2. The holder together with the filter was placed over a 5 cm^2 round hole in the front face of the chamber wall, secured using an airtight seal. Air was drawn through the filter at a rate of approximately 1.76 L/minute using a vacuum pump (Edwards RB 5). The volume of each sample taken from the atmosphere of the test material was a standard 20 litres. Each filter was weighed before and after sampling in order to calculate by difference the weight of dust collected. Knowing the weight of dust collected during each sample time, and the total volume of chamber air drawn through the filter, the chamber concentration of each substance was calculated. The results of each individual sample taken during each of the exposures were averaged to give the mean concentration of the test material within each of the chambers over the 4 hour exposure period. The amount of test material that was present on each filter was estimated using an analytical method supplied to by the Analytical Research Laboratories, Rhone Poulenc, Vitry-sur-Seine, France.

Analytical method:
Methylation: Methylate, when dissolved in ethyl ether, acetone or dichloromethane, by one of the standard techniques using diazomethane.
Gaseous phase chromatography: Inject 2 µL of the solution obtained as above under the following conditions:
Apparatus: Pye Unicam GCV.
Column: Glass, 2 metre x 5 mm i.d.
Phase: NPGS (neopentylglycolsuccinate) 5 % on EMBACEL 60/ 100 mesh
Temperature: Injector 180 °C, Detector 230 °C, Column 180 °C
Carrier Gas: Nitrogen (flow rate 60 cm^3/minute)
Detector: Flame ionisation (Hydrogen flow rate 66 cm^3/minute, air at 500 cm^3/minute)
Recorder: 1 mV full range

Calculations:
The calculation is done by measuring the surface areas by one or other of the following two methods:
a) by comparison with a standard solution of methylated test material prepared and injected under the same conditions as the test preparation (external standard);
b) by the internal standard method with 2-(2,4-dichlorophenoxy) propionic acid added to the test solution before methylation.

Estimation of the particle size distribution: The particle size distribution of each dispersed sample was estimated during the 4 hour exposure period using an Andersen Mini-Sampler (2000 Inc. Salt Lake City, Utah, USA). This device consists of 4 metal impaction stages and a back-up glass fibre filter (Whatman GF/C-2.5 cm diameter) housed within an aluminium can 2.8 cm in diameter, 3.1 cm in length. Each impaction plate is 2.5 cm in diameter. The sampling rate is a standard 1.4 L/minute and the collection characteristics at this flow rate are listed below:
Plate 1 - particles greater than 5.5 μm diameter.
Plate 2 - particles between 3.5 and 5.5 μm diameter.
Plate 3 - particles between 2.0 and 3.5 μm diameter.
Plate 4 - particles between 0.3 and 2.0 μm diameter.
Filter - particles below 0.3 μm diameter.
A single sample was taken during each of the 4 hour exposures through a 5.0 cm^2 round hole in the exposure chamber wall. An airtight seal was made around the chamber wall and chamber air was drawn through the mini-sampler by a Casella general purpose sampler, Mark II, model C. Each stage of the sampling device was cleaned and weighed immediately prior to use, and after sampling reweighed. The weight of dust collected on each stage was calculated by difference.


RESULTS OF THE CHAMBER ATMOSPHERE CONDITIONS
- The dust of the test material dispersed evenly throughout the exposure chambers. The mean concentrations of airborne dust within the exposure chambers during the 4 hour exposure periods was calculated to be 0.02 ± 0.01 (SD) g/m^3
- The estimated nominal concentration was calculated to be 1.45 g/m^3 for the test material (the mean measured airborne concentration of the dust was 1.4 % of the nominal concentration). The discrepancy can be accounted for by the fact that a significant proportion of the dispersed dust was deposited around the end of the connecting column, this proportion of the generated dust consisting of particles too large to remain airborne. The soft nature of the test material resulted in a very low proportion of airborne particles present in the chamber atmosphere.
- Each of the gravimetric samples taken during exposure was analysed using a gas chromatograph in order to establish the amount of test material present. The mean chamber air concentration of test material present in the atmosphere during exposure, calculated from these results are 0.012 g/m^3. The mean proportion of test material in each sample was calculated to be 60 %. The low proportion is considered due to the fact that the amount of airborne dust collected on the filters was so low that the weighing error became significant. The amounts collected were in the order of less than 1 mg.
- Estimation of the particle size distribution, using an Andersen mini-sampler, revealed that 73 % of the particles present in the chamber air were considered respirable (i.e. below 5.5 μm diameter).

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

The estimated nominal concentration was calculated to be 1.45 g/m^3.

No. of animals per sex per dose:

5 animals per sex per dose

Control animals:

yes

Remarks:

Animals received clean air only for 4 hours.

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All rats were observed at frequent intervals throughout each of the 4 hour exposure periods. Frequent checks on appearance and behaviour were made subsequently during the 14 day post exposure observation period. All animals were observed at least twice daily during this time. All rats were weighed immediately prior to exposure (day 0), the day following exposure (day 1) and subsequently on days, 3, 7, 10 and 14 post exposure. From the individual bodyweights the group mean bodyweight at each of these stages during the study was calculated. The amount of food consumed by each cage of rats was measured daily, and the average amount consumed by a single rat in each cage was calculated.
- Necropsy of survivors performed: Yes. Immediately following exposure, 2 male and 2 female animals from the control group and group 2 (test) identified before the start of exposure, were anaesthetised by intraperitoneal injection of pentobarbitone sodium. The subclavian blood vessels were exposed, cut and the animals allowed to bleed out. The respiratory tract of these animals was subjected to detailed macroscopic examination. The lungs were dissected out and weighed in order to calculate the lung to bodyweight ratio of each animal. At the end of the 14 day post exposure observation period all surviving animals were anaesthetised, killed by exsanguination and detailed macroscopic examination carried out. This included the opening of the abdominal, thoracic and cranial cavities. The lungs of all animals were dissected out and weighed after removing the thymus; heart and oesophagus together with the trachea above the carina. From the data obtained, the lung to bodyweight ratio was calculated for each of the animals.

Sex:

male/female

Remarks on result:

other: It was not possible to generate the dust of the test material above a mean level of 0.02 g/m^3.

Mortality:

There were no deaths.

Clinical signs:

other: Avoidance reactions and peripheral vasodilation.

Body weight:

On day 3 lower bodyweights were recorded for female rats exposed to the test material. The bodyweight gain of all animals from day 3 onwards of the observation period was similar and considered normal.

Gross pathology:

- Lung to bodyweight ratios: The lung to bodyweight ratios all animals killed either immediately following exposure or at the end of the 14 day post exposure observation period were considered normal.
- Macroscopic pathology: No changes related to exposure to the dust of the test material were seen, either at the end of exposure or at the end of the 14 day observation period. Other incidental findings not regarded as significant, included the appearance in the lungs of some animals of purplish areas considered due to inadequate bleeding out prior to post mortem examination.

Other findings:

CLINICAL SIGNS
Non-specific reactions, typified by licking of the inside of the mouth and blinking of the eyes were seen during the first 5 - 10 minutes of exposure to the test material.
Reactions to the presence of the dust of the test material remained non-specific until approximately 3.5 hours into the exposure, when avoidance reactions were noted. These were typified by all animals seeking the corners of the exposure chamber presumably to avoid the presence of the dust. At this time 7 animals were noted to be showing signs of peripheral vasodilatation. However, all rats were behaving normally 10 minutes following the end of exposure and no adverse effects were noted during the 14 day observation period.

FOOD CONSUMPTION
Less food was consumed overnight following exposure by both male and female animals exposed to the test material. Thereafter food consumption was considered normal over the remainder of the 14 day observation period.

Measured Dust Concentrations within the Exposure Chamber (Gravimetric Analysis)

Sample No.	Time Sample Taken During Exposure	Weight of Filter (mg)	Weight Filter and Dust (mg)	Weight Dust Collected (mg)	Total Volume Sampled (L)	Atmospheric Concentration of Test Material (g/m^3)
1	29 min	57.5	57.8	0.5	20.0	0.015
2	1 h 15 min	56.8	57.3	0.5	20.0	0.025
3	2 h 14 min	56.5	57.0	0.5	20.0	0.025
4	2 h 55 min	57.6	58.0	0.4	20.0	0.020
5	3 h 37 min	57.4	57.7	0.3	20.0	0.015

Mean chamber concentration of test material = 0.02 ± 0.01 g per cubic metre of chamber air.

 

Test Material Content of Gravimetric Samples Taken During Exposure

Sample No.	Time Sample Taken During Exposure	Total Weight of Dust Collected (mg)	Test Material Content (mg)	Percentage Test Material in Sample	Volume of Chamber Air Sampled (L)	Atmospheric Concentration (Expressed as Test Material (g/m^3)
1	29 min	0.3	0.328	108	20.0	0.016
2	1 h 15 min	0.5	0.171	34	20.0	0.009
3	2 h 14 min	0.5	0.240	48	20.0	0.012
4	2 h 55 min	0.4	0.262	66	20.0	0.013
5	3 h 37 min	0.3	0.158	53	20.0	0.008

Mean concentration = 0.012 ± SD 0.003 g per cubic metre of chamber air.

 

Calculated Nominal Concentrations

Weight of dust from generator = 8.2 g

Eight of dust collected from column = 1.22 g

Weight actually dispersed into chamber = 6.98 g

Airflow through generator = 20 L/min

Total airflow through generator in 4 h = ((20 x 4 x 60) / 1 000) = 4.8 m^3

Nominal concentration of test material during the 4 h exposure period = 1.45 g/m^3

 

Particle Size Distributions (By Weight) Anderson Mini-Sampler

Test material sample removed 1 h 14 min into exposure.

	Size ranges of Anderson Mini Sampler					Total
	< 0.3 μm	0.3 – 2.0 μm	2.0 – 3.5 μm	3.5 – 5.5 μm	> 5.5 μm
Weight (mg)	0.0	0.6	0.6	0.7	0.7	2.6
Percentage	0	23.1	23.1	26.9	26.9	100 %
Cumulative percentage	0	23.1	46.2	73.1	100.0

73 % particles were less than 5.5 μm; considered respirable.

Interpretation of results:

study cannot be used for classification

Conclusions:

Under the conditions of this study it was not possible to generate the dust of the test material above a mean level of 0.02 g/m^3.
It was found to be difficult to generate a significant level of dust of the test material due to the cohesive nature of the material. It is expected that the test material is unlikely to produce any appreciable level of respirable dust under normal handling conditions.

Executive summary:

The acute inhalation toxicity of the test material was investigated in male and female rats. Animals were exposed (whole body) to the test material for 4 hours.

The test material that was used in the Wright Dust generator has first to be packed under pressure into the canister, and the yield of aerosol has been found to be dependant upon the nature of this packed material. The test material was sensitive to pressure and wax-like inclusions were formed in the material during packing. Due to the nature of the packed sample it was not possible to use the Wright Dust generator at gear ratios in excess of 1: 1 and only a low level of aerosol was produced in the exposure chamber. The behaviour of the test material was considered to be related to the purity and the physical form of the sample as received.

No mortalities occurred and animals gained expected body weight over the 14 day observation period. No treatment-related abnormalities were noted at necropsy.

Under the conditions of this study it was not possible to generate the dust of the test material above a mean level of 0.02 g/m^3. It was found difficult to generate a significant level of dust of the test material due to the cohesive nature of the material. It is expected that the test material is unlikely to produce any appreciable level of respirable dust under normal handling conditions.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

> 12.5 mg/L air

Physical form:

inhalation: dust / mist

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 200 - 300 g
- Housing: Cages were made of stainless steel with wire mesh, type DKIII. Animals were housed 1 per cage.
- Water: Ad libitum tap water.
- Acclimation period: at least 1 week.

ENVIRONMENTAL CONDITIONS
- Temperature: 20 to 24 °C
- Humidity: 30 to 70 % relative humidity
- Photoperiod: 12 hours light/ 12 hours dark (06.00 - 18.00 hours/ 18.00 - 06.00 hours)

Type of coverage:

semiocclusive

Vehicle:

CMC (carboxymethyl cellulose)

Details on dermal exposure:

TEST SITE
- Area of exposure: Dorsal and dorso-lateral parts of the trunk; about 50 cm x 50 cm.
- The test suspension was applied in the morning. The test site was clipped at least 15 hours before application.
- Type of wrap if used: The application site was covered with a semi-occlusive dressing for 24 hours.

REMOVAL OF TEST SUBSTANCE
- Washing: 24 hours after application the dressing was removed and the application site was rinsed with warm water.

TEST MATERIAL
- 0.5 % aqueous carboxymethyl cellulose formed a 30 % w/v suspension with the test material.
- Amount(s) applied: for the 4 000 mg/kg treatment 13.3 mL/kg was applied. For the 2 000 mg/kg treatment 6.7 mL/kg was applied.
- Concentration: 30 % w/v

VEHICLE
- Aqueous formulation corresponds to the physiological medium.

Duration of exposure:

24 hours

Doses:

2 000 and 4 000 mg/kg

No. of animals per sex per dose:

5 males and 5 females

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Scoring of skin findings: 30 - 60 minutes after removal of the semi-occlusive dressing and at least once weekly during the following observation period.
- Recording of signs and symptoms: Several times on the day of application, and at least once each work day. Checks for moribund and dead animals twice each work day and once on holidays.
- Necropsy of survivors performed: Yes. Food was withdrawn 16 hours before sacrifice with CO2, then necropsy with gross pathological examination was performed.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 4 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: No abnormalities were observed in any of the test animals. Erythema was observed.

Gross pathology:

No abnormalities were detected in the necropsy of sacrificed animals.

Interpretation of results:

other: Not classified in accordance with EU criteria.

Conclusions:

Under the conditions of this study, the acute dermal LD50 of the test material to rats was > 4 000 mg/kg.

Executive summary:

The acute dermal toxicity of the test material was investigated in a study similar in design to OECD 402.

Ten male and female wistar rats were treated dermally with the test material at doses of 2 000 or 4 000 mg/kg for 24 hours. 30 - 60 minutes after removal of the semi-occlusive dressing and at least once weekly during the following observation period skin observations were performed. The animals were observed for 14 days before gross necropsy was performed.

No abnormalities were observed in any of the test animals but erythema was observed. No mortality occurred. Body weights increased during the observation period following test material application and no abnormalities were detected in the necropsy of sacrificed animals.

Under the conditions of this study, the acute dermal LD50 of the test material to rats was > 4 000 mg/kg.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 4 000 mg/kg bw

Additional information

Acute Oral Toxicity Key Study: Kirsch (1983)

The acute oral toxicity of the test material was investigated in a study similar in design to OECD 401. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

Five male and five female Wistar rats were treated orally with the test material at doses of: 681, 1 000, 1 470 and 2 150 mg/kg in a single administration by gavage. The animals were observed for 14 days, before gross necropsy was performed.

Mortality and clinical abnormalities were observed at dose levels 1 000, 1 470 and 2 150 mg/kg, body weights increased during the observation period at all doses. In the animals that died, the gross pathology found abnormalities such as stomach ulcers, slightly atonic intestines and strikingly filled bladders in some animals. In the sacrificed animal, tip of the forestomach thickened. In the remaining animals, no abnormalities were observed.

Under the conditions of this study, the acute oral LD50 of the test material was 1166 mg/kg.

 

Acute Inhalation Toxicity Key Study: Klimisch (1986)

The acute inhalation toxicity of the test material was investigated in a study design based on the OECD 403 guideline. The study was conducted under with GLP conditions. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

10 male and 10 female Wistar rats per group were exposed to concentrations of 5.4, 9.5 and 12.5 mg/L of the active ingredient for a period of 4 hours.

During the exposure the following clinical signs were observed: single attempts to escape, irregular to jerky respiration, reddish nasal discharge. After the exposure irregular to jerky respiration, sounds of respiration, unsteady gait, noses partly with reddish smear or encrustations, reduced state of health and apathy were observed. In animals that died during the exposure period general congestion, slight oedematisation and some slightly sunken darker areas at the lung were found. In sacrificed animals no abnormalities were observed.

Under the conditions of this study, the acute inhalation LC50 (4 h) of the test material was found to be >12.5 mg/L.

 

Acute Inhalation Toxicity Supporting Study: Coombs (1977)

The acute inhalation toxicity of the test material was investigated in male and female rats. Animals were exposed (whole body) to the test material for 4 hours. The study was conducted under with GLP conditions. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

The test material that was used in the Wright Dust generator has first to be packed under pressure into the canister, and the yield of aerosol has been found to be dependant upon the nature of this packed material. The test material was sensitive to pressure and wax-like inclusions were formed in the material during packing. Due to the nature of the packed sample it was not possible to use the Wright Dust generator at gear ratios in excess of 1: 1 and only a low level of aerosol was produced in the exposure chamber. The behaviour of the test material was considered to be related to the purity and the physical form of the sample as received.

No mortalities occurred and animals gained expected body weight over the 14 day observation period. No treatment related abnormalities were noted at necropsy.

Under the conditions of this study it was not possible to generate the dust of the test material above a mean level of 0.02 g/m^3. It was found difficult to generate a significant level of dust of the test material due to the cohesive nature of the material. It is expected that the test material is unlikely to produce any appreciable level of respirable dust under normal handling conditions.

 

Acute Dermal Toxicity Key Study: Kirsch (1983)

The acute dermal toxicity of the test material was investigated in a study similar in design to OECD 402. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

Ten male and female wistar rats were treated dermally with the test material at doses of 2 000 or 4 000 mg/kg for 24 hours. 30 - 60 minutes after removal of the semi-occlusive dressing and at least once weekly during the following observation period skin observations were performed. The animals were observed for 14 days before gross necropsy was performed.

No abnormalities were observed in any of the test animals but erythema was observed. No mortality occurred. Body weights increased during the observation period following test material application and no abnormalities were detected in the necropsy of sacrificed animals.

Under the conditions of this study, the acute dermal LD50 of the test material to rats was > 4 000 mg/kg.

Acute Intraperitoneal Toxicity Supporting Study: Kirsch (1988)

The acute toxicity of the test material after a single intraperitoneal administration was investigated, under GLP conditions. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997). 5 male and 5 female Wistar rats per dose group were administered 200 and 700 mg/kg body weight by a single injection into the abdominal cavity. The test material was prepared with 0.5 % aqueous carboxymethyl cellulose. Unspecific clinical symptoms were observed. Mortality occurred in the dosage of 700 mg/kg. Necropsy findings in animals that died: moderately clear liquids in the abdomen. In sacrificed animals: liver: intraabdominal conglutinations, blunt margins; spleen: serosa opalescent. In dosage 200 mg/kg no mortality occurred (LD0 = 200 mg/kg) and symptoms occurred at each dosage (ED0 = < 200 mg/kg).
Under the conditions of this study, the acute LD50 after a single intraperitoneal administration of test material in male and female rats was found to be > 200 < 700 mg/kg.

 

Acute Intraperitoneal Toxicity Supporting Study: Kirsch (1983)

The acute toxicity of the test material after a single intraperitoneal administration was investigated. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

5 male and 5 female Wistar rats per dose group were administered at 215, 316, 464, and 681 mg/kg body weight by a single injection into the abdominal cavity. The test material was prepared with 0.5 % aqueous carboxymethyl cellulose. Unspecific clinical symptoms were observed. Mortality occurred in the dosage of 464 and 681 mg/kg. Necropsy findings in animals that died included general congestion, contents of the stomach/intestines bloody in some animals, liver: loam-coloured in some animals, occasionally very fine fibrinous deposits. Urinary bladders: In several animals strikingly filled, but contents clear. Sacrificed animals: Spleen: Milky serosa, slight to marked intraabdominal adhesions. Liver: Considerably rounded in some animals.

Under the conditions of this study, the acute LD50 after a single intraperitoneal administration of test material in male and female rats was approximately 464 mg/kg bw.

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to acute dermal or inhalation toxicity.

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does require classification with respect to acute oral toxicity (Category 4, H302: Harmful if swallowed).