polymeric zinc propylenebis(dithiocarbamate);propineb (ISO)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004/6/11 to 2004/7/21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

Version / remarks:

1996

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: JMAFF guideline

Version / remarks:

12 Nousan No 8147, Nov. 24, 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Cell numbers per volume (as a surrogate for biomass per volume) were estimated photometrically. For this purpose, small samples of treated, inoculated test medium were placed in 5 cm cuvettes on day 1, day 2, and day 3 of the exposure period (without replacing after measurement). The extinctions were determined at a wave length of 578 nm using a single-beam-photometer (WTW MPM 1500). The photometer was calibrated using culture medium without algae. Cell numbers were computed from extinction values using the conversion formula logio (cell no.) = 6.386438 + 1.141336 x log™ (extinction). To detect possible alterations in algae cells that might influence extinction measurements, such as unusual cell size, samples from each flask were examined under a microscope at a magnification of 400 times. Cell numbers were estimated photometrically only if alterations that might influence extinction were not detected. At exposure termination, the contents of all replicate vessels were combined, and the pH was measured. The test solutions were then submitted for the day 3 analyses.

Vehicle:

yes

Remarks:

DMF

Details on test solutions:

0.607 g test item were dissolved ad 50 mL DMF immediately prior to the test. The stock solution was well agitated on a magnetic stirrer for at least 1 minute before further use. An adequate amount of the stock solution was transferred to a dilution series with DMF. 100 µL of the dilutions/L nutrient medium were used to obtain the concentration levels used in the study.

Test organisms (species):

other: Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Collection of Algal Cultures, Inst. for Plant Physiology, University of Gottingen. Strain material of defined sensitivity was used, as shown by reference substance testing with 3,5-dichlorophenol or potassium dichromate. Such reference tests are done erratically (i.e. event driven in case of receiving new strains, introduction of new test conditions, apparatus, etc.). Such work is documented and archived together with strain protocols. 200 µL of a 7-9 days old stock culture was transferred into a 250 ml cotton plugged Erlenmeyer flask containing 50 ml of nutrient medium once every week. Stock cultures of algae were kept at 23 ± 2°C with 16 h light/day. All operations were conducted under sterile conditions to handle an axenic^2 algae culture. The medium was freshly prepared according to the mentioned test. Analytical grade salts were dissolved in purified (Milli-Q-water) water (see table one for nominal nutrient medium concentrations).

Test type:

static

Water media type:

other: Nutrient medium

Limit test:

no

Total exposure duration:

3 d

Test temperature:

24.5 – 25.0°C

pH:

7.9 – 8.4

Nominal and measured concentrations:

Nominal concentrations: 0.003, 0.010, 0.031, 0.10, 0.31 and 1.0 mg a.s./L, Mean measured concentrations: 0.003, 0.009, 0.052, 0.213 and 0.855 mg a.s./L

Details on test conditions:

The test volume was 150 mL test medium per replicate. 3 replicate vessels per test level (6 replicate vessels per control level) for biological data evaluation and, if needed, additional test vessels for analytical determination. The test vessels (300 mL-Erlenmeyer flasks) labelled with the study number, series number, and concentration of the test item were sealed with cotton wool or cellulose plugs and placed in a growth incubator.

To ensure that the algae used as inoculum were exponentially growing, an inoculum pre-culture was prepared 2-4 days before the start of the test and cultivated under the same conditions as in the main test. In order to reach an initial cell density of 10,000 cells/mL in the test medium at the beginning of the 72 hours exposure period of the main test, adequate dilution of the pre-culture was done with nutrient medium. The density of the inoculum was 10,000 cells/mL.

The exposure of individual flasks to permanent light was made more uniform by randomised repositioning after each observation day, the light intensity ranged nominally from 8000 lux (± 15 %). Test vessels were placed on a tablet rotating 100 rpm to prevent sedimentation of the cells without additional aeration.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

0.022 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.009 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Table three

Sectional growth rates of the control

	Sectional Growth rate (μ) (days^-1)
	0-24h	24-48h	48-72h	%CV
Control	1.279	1.249	1.360	4.4

 

 

Table four

 

Effect of propineb on Freshwater Algae (Pseudokirchneriella subcapitata) in a 72 h growth inhibition test

Geom. mean measured concentration [mg a.s./L]	Cell number after 72 h (means) per mL	(0-72h)-average specific growth rates [days^-1]	Inhibition of average specific growth rate [%]
Control	493 000	--	--
Solvent control	493 000	--	--
Pooled controls	493 000	1.296	--
0.003	428 000	1.252	3.4
0.010	259 000	1.081	16.6
0.031	165 000	0.934	27.9
0.10	35 000	0.406	68.7
0.31	16 000	0.123	90.5
1.0	4 000	-0.754	158.1

 

 

Table five

Summary of results 

 

		Based on nominal concentrations	based on mean measured concentrations
Average Growth Rate (0 - 72 h)	ErC50 Cl 95% LOErC NOErC	0.055 mg a.s./L 0.041 - 0.074 0.10 mg a.s./L 0.031 mg a.s./L	0.022 mg a.s/L 0.014-0.035 0.052 mg a.s./L 0.009 mg a.s/L
Average Growth Rate (0 - 48 h)	ErC50 Cl 95% LOErC NOErC	0.047 mg a.s./L 0.034 - 0.065 0.031 mg a.s./L 0.010 mg a.s./L	0.018 mga.s./L n.d. <0.003 mg a.s./L <0.003 mg a.s./L
Average Growth Rate (0 - 24 h)	ErC50 Cl 95% LOErC NOErC	0.1 95 mg a.s./L 0.077 - 0.639 0.031 mg a.s./L 0.010 mg a.s./L	0.1 07 mg a.s./L n.d. 0.009 mg a.s./L 0.003 mg a.s./L
Biomass Integral (0 - 72 h)	EbC50 Cl 95% LOEbC NOEbC	0.017 mg a.s/L 0.012-0.023 0.010 mg a.s/L 0.003 mg a.s./L	0.005 mg a.s./L 0.003 - 0.006 O.003 mg a.s./L <0.003 mg a.s./L
Biomass Integral (0 - 48 h)	EbC50 Cl 95% LOEbC NOEbC	0.029 mg a.s./L 0.023-0.037 0.010 mg a.s./L 0.003 mg a.s./L	0.009 mg a.s./L 0.008-0.012 O.003 mg a.s./L <0.003 mg a.s./L
Biomass Integral (0 - 24 h)	EbC50 Cl 95% LOEbC NOEbC	0.093 mg a.s./L 0.044 - 0.200 0.031 mg a.s./L 0.010 mg a.s./L	0.039 mg a.s./L n.d. 0.009 mg a.s./L 0.003 mg a.s./L

Validity criteria fulfilled:

yes

Conclusions:

The aim of the study was to determine the influence of propineb on exponentially growing Pseudokirchneriella subcapitata. Algae were exposed for 3 days under static exposure conditions to the nominal concentrations of 0.003, 0.010, 0.031, 0.10, 0.31 and 1.0 mg a.s./L in comparison to control(s).
Based on mean measured concentrations, the 72-h ErC50 and NOEC (base on growth rate) were determined to be 0.022 mg a.s./L and 0.009 mg a.s./L.

Executive summary:

The aim of the study was to determine the influence of propineb on exponentially growing Pseudokirchneriella subcapitata. Algae were exposed for 3 days under static exposure conditions to the nominal concentrations of 0.003, 0.010, 0.031, 0.10, 0.31 and 1.0 mg a.s./L in comparison to control(s).

Test conditions met all validity criteria, given by the mentioned guideline(s). Based on mean measured concentrations, the 72-h E_rC₅₀ and NOEC (base on growth rate) were determined to be 0.022 mg a.s./L and 0.009 mg a.s./L.

Description of key information

The aim of the study was to determine the influence of propineb on exponentially growing Pseudokirchneriella subcapitata. Algae were exposed for 3 days under static exposure conditions to the nominal concentrations of 0.003, 0.010, 0.031, 0.10, 0.31 and 1.0 mg a.s./L in comparison to control(s).

Test conditions met all validity criteria, given by the mentioned guideline(s). Based on mean measured concentrations, the 72-h E_rC₅₀ and NOEC (base on growth rate) were determined to be 0.022 mg a.s./L and 0.009 mg a.s./L.
 

Key value for chemical safety assessment

EC50 for freshwater algae:

0.022 mg/L

EC10 or NOEC for freshwater algae:

0.009 mg/L

Additional information

One study that was not included in the endpoint summary was performed by Heimbach, 1989. The green algae (Scenedesmus subspicatus) were exposed under static conditions to nominal concentrations of 0.074, 0.13, 0.24, 0.41, 0.74, 1.3, 2.4, 4.1 and 7.4 mg a.s./L. After 24, 48, 72 and 96 hours cell counts were determined. The 96-h E_rC₅₀ (based on growth rate) and the NOEC were determined to be 1.8 mg a.s./L and 0.44 mg a.s./L, respectively.

The second study not included in the endpoint summary was performed by Bruns, 2010. The test guidlelines used in this study were OECD 201, and all test conditions met all validity criteria, given by the mentioned guideline(s). The aim of the study was to determine the influence of the test item on exponentially growing Pseudokirchneriella subcapitata. The 72-h E_rC₅₀ and NOEC (based on growth rate) were determined to be  166 µg a.s./L and 6.63 µg a.s./L, respectively.