Propargite

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22nd April 2001 to 8 September 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Duplicate aliquots (approximately 530 mL) were removed from each test vessel at 24 hours prior to the addition of the Daphnia, at 0 hours and at 48 hours.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 50.16 mg test material was dissolved in 50 mL acetone and serially diluted in acetone to prepare stock solutions
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Age at study initiation (mean and range, SD): 6-24 hours old
- Method of breeding: acyclical parthenogenesis
- Feeding during test: none

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20.9-21.3 ºC

pH:

7.56-7.94

Dissolved oxygen:

≥80 % of air saturation value

Nominal and measured concentrations:

0, 0.00625, 0.0125, 0.05 and 0.1 ppm (nominal)

0, 0.004, 0.013, 0.015, 0.051 and 0.08 ppm (measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass moulded beakers of approximately 3 litre capacity containing Daphnia test chambers
- Material, size, headspace, fill volume: test chambers were constructed of 250 mesh stainless steel (38 mm depth, 75 mm diameter); fill volume of test vessels - approximately 2 litres of solution
- Type of flow-through: test medium from a header tank was passed into a glass mixing vessel at each test concentration; medium was mixed with a continuous flow of stock solution of test material; stock solutions were delivered using Medfusion Syringe Infusion Pumps; mixing vessels were placed on magnetic stirrers to ensure adequate mixing of test solutions and each mixing vessel contained one outlet leading directly to the appropriate test and control vessels.
- Renewal rate of test solution: flow rate - 14 mL/min
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Conductivity: 477-562 µS

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light; 8 hours dark
- Light: illumination was provided by artificial daylight fluorescent tubes

RANGE-FINDING STUDY
- Test concentrations: 0, 0.001, 0.01, 0.1 and 1 ppm
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

0.014 other: ppm

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % C.L. 0.03-0.046

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.014 other: ppm

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % C.L. 0.011-0.019

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

0.015 other: ppm

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.004 other: ppm

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- After 24 h exposure, 100 % immobile Daphnia were observed at 0.08 ppm, 65 % at 0.051 ppm and 5 % at 0.013 ppm. By 48 hours, 95 % immobile Daphnia were recorded at 0.051 ppm, 45 % at 0.015 ppm , 35 % at 0.013 ppm and 15 % at 0.004 ppm.

Range-finding test

After 24 hours exposure, all Daphnia at 1 ppm were immobile with 50 % immobile at 0.1 ppm. After 48 hours exposure, all Daphnia at 0.1 ppm were immobile with 10 % immobile at 0.01 ppm. No other immobile Daphnia were recorded at any other test concentration.

Definitive test

Table 1: Cumulative number of immobile Daphnia

		Concentration (ppm)
Time (h)	Replicate	Non-solvent control	Solvent control	0.004	0.013	0.015	0.051	0.08
24	A	0	0	0	0	0	3	5
	B	0	0	0	0	0	5	5
	C	0	0	0	1	0	2	5
	D	0	0	0	0	0	3	5
	% immobile	0	0	0	5	0	65	100
48	A	0	0	0	1	3	5	5
	B	0	0	1	2	4	5	5
	C	0	0	0	3	1	5	5
	D	0	0	2	1	1	4	5
	% immobile	0	0	15	35	45	95	100

Validity criteria fulfilled:

not specified

Conclusions:

Under the conditions of the test, the 48 hour EC50 to Daphnia magna in a flow-through test system, based on mean measured concentrations, was 0.014 ppm. The 48 hour NOEC was 0.004 ppm.

Executive summary:

The EC50 for immobilsation of Daphnia exposed to propargite was determined over a 48 hour period in a study conducted in line with standardised guidelines OECD 202 and EU Method C.2.

The nominal concentrations of propargite tested were 0, 0.00625, 0.0125, 0.025, 0.05 and 0.1 ppm with the corresponding overall mean measured concentrations being 0.000, 0.004, 0.013, 0.015, 0.051 and 0.080 ppm, respectively. Chemical analysis of samples taken at 0 and 48 hours indicate that the concentrations were reasonably well maintained over the test period. Propargite was poorly soluble and was added to the test system with acetone as a co-solvent. No undissolved test material was observed in the test vessels.

Four vessels were prepared at each test concentration with a solvent and non-solvent control included. Five Daphnia were added to each test vessel.

The EC50 and NOEC were estimated based in an overall mean measured concentrations of propargite:

		95 % confidence limits
Timepoint (h)	EC50 value (ppm)	Lower limit	Upper limit	NOEC (ppm)
24	0.038	0.030	0.046	0.015
48	0.014	0.011	0.019	0.004

Test solution quality parameters were measured at the beginning and at 24 hour intervals at all concentrations. All parameters remained within acceptable limits.

Description of key information

48 hour LC50 0.014 mg/L; study conducted in accordance with OECD Guideline 202 and EU Method C.2; Knight and Allan, 2002

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.014 mg/L

Additional information

The nominal concentrations of propargite tested were 0, 0.00625, 0.0125, 0.025, 0.05 and 0.1 ppm with the corresponding overall mean measured concentrations being 0.000, 0.004, 0.013, 0.015, 0.051 and 0.080 ppm, respectively. Four vessels were prepared at each test concentration with a solvent and non-solvent control included; five Daphnia were added to each test vessel.

The EC50 and NOEC were estimated based in an overall mean measured concentrations of propargite:

		95 % confidence limits
Timepoint (h)	EC50 value (ppm)	Lower limit	Upper limit	NOEC (ppm)
24	0.038	0.030	0.046	0.015
48	0.014	0.011	0.019	0.004