Diammonium peroxodisulphate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-01-14 to 1992-01-24

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

,modified to marine conditions

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

not specified

Details on sampling:

NA

Vehicle:

no

Details on test solutions:

The test media were prepared using a stock solution in ISO-medium. For this purpose the test substance was added quantitatively to obtain a concentration of 2000 mg/L. From this stock solution the required volumes for preparation of the test concentrations were added to ISO-medium. The final volume of the test solutions was 100 mL. At the start of the test all test solutions were clear.

Test organisms (species):

Phaeodactylum tricornutum

Details on test organisms:

TEST ORGANISM
- Common name: Phaeodactylum tricornutum
- Strain: CCAD 1052/1A
- Source: no information available
- Age of inoculum: four days
- Method of cultivation: no information available´

ACCLIMATION
- Acclimation period: no information available

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

NA

Hardness:

NA

Test temperature:

19.5 - 24.5 °C

pH:

7.8 - 9.0

Dissolved oxygen:

NA

Salinity:

NA

Nominal and measured concentrations:

Nominal: 0, 3.2; 10; 32, 100, 320; 1000 mg/L

Details on test conditions:

Test type: static;
Test vessels: 250 mL, all-glass
Medium: ISO-medium formulated according to the International Standards "Water quality - Marine algal growth inhibition test" with Skeletonema costatum and Phaeodactylum tricornutum October 1988 (formulated using synthetic seawater, prepared with Milli-Q water, in such way that precipitation does not occur). Composition of ISO-medium see sect. "Any other information on materials and methods incl..."
Milli-Q water: Tap water purified by reverse osmosis and subsequently passed over activated carbon and ion exchange cartridges (Millipore Corp., Bedford, Mass., USA)
Cell density: Using a four-day old preculture with a cell density of 16.5E05 cells/mL, cell suspensions of 2E04 cells/mL were prepared. Of these suspensions 55 mL was mixed with 55 mL of the test solutions resulting in an initial cell density of 1E04 cells/mL.
Test duration: 72 hours
Illumination: continuously using TLD-lamps of 18 Watt (Philips, Spain), yielding 6000 - 7000 lux
Temperature of the medium: 23 +/- 2 °C
Incubation: During incubation the algal cells were kept in suspension by continuous shaking
Test concentrations: 3.2, 10, 32, 100, 320 and 1000 mg/L
Control: Test medium without test substance or other additives (0 mg/L)
Replicas: 3 replicas of each test concentration; 6 replicas of the control

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

136 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: cell growth inhibition (EbC50: 0-72 h)

Remarks on result:

other: 95 % confidence interval: 63 - 281 mg/L;

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate reduction (ErC50: 0-72 h)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: cell growth inhibition and growth rate reduction

Details on results:

At and below 100 mg/L and in the blank control exponential increase in cell growth was recorded during 72 hours of exposure. From nominally 100 mg/L cell growth decreased with increasing concentration of the test item. Inhibition of cell growth and reduction of growth rate. Inhibition of cell growth and growth rate reduction increased with increasing concentration of the test material resulting in 100 % inhibition and growth rate reduction at nominally 1000 mg/L. The apparent inhibition at 32 mg/L was caused by variation in the extinction values and is therefore not considered to be biologically relevant. The EC50 (72 h) based on growth rate was 136 mg/L.

Results with reference substance (positive control):

The sensitivity of the used test system was checked using potassium dichromate.
Concentrations:1.0, 3.2, 10, 32 and 100 mg/L
Control: blank
Results:
The nominal 72-hour EC50 for growth inhibition(EbC50: 0-72 h) was 7.07 mg/L (95 % confidence interval of 1.79 - 23.02 mg/L)
The nominal 72-hour EC50 for growth rate reduction (ErC50: 0-72 h) was between 10 and 32 mg/L

Reported statistics and error estimates:

Statistics were performed with Probit regression analysis (Finney, D.J., 1971: Probit analysis, Cambridge University Press, Cambridge, U.K., 3rd edition).

TABLE 1: Mean cell densities *

 

Number of cells inoculated at t=0:1 x 10⁴ cells/ml

 

Nominal concentration mg/l	0h	24h	48h	72h
0	1.0	1.7	9.6	39.3
3.2	1.0	1.6	11.1	50.4
10	1.0	2.2	11.5	47.2
32	1.0	1.3	8.5	35.9
100	1.0	1.8	7.5	23.2
320	1.0	1.3	4.5	7.6
1000	1.0	1.0	1.3 **	1.0

 

* A variation of±0.1 is acceptable owing to rounding off by the programme used for calculations.

** This value may be assumed to be 1.0, since mean cell densities at t=24 and t=72 are also 1.0

 

TABLE 2: Percentage inhibition of cell growth and percentage reduction of growth rate.

 

Nominal concentration mg/l	Area (A)% Inhibition		Growth rate
			cells/h	%reduction
			0h-72h
0	682		0.0510
3.2	848	-24	0.0544	-7
10	836	-23	0.0535	-5
32	609	11	0.0497	2
100	440	35	0.0437	14
320	171	75	0.0282	45
1000	0	100	0.0000	100

 

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test with Phaeodactylum tricornutum, diammonium sulfate inhibits cell growth and reduces growth rate of this marine algae species at nominally 100 mg/L and higher. The EbC50 (72 h) value for cell growth inhibition was 136 mg/L. The ErC50 (72 h) for growth rate reduction was in the range of 320 mg/L. The NOEC was 32 mg/L.

Executive summary:

The marine algae Phaeodactylum tricornutum was tested according to OECD guideline 201 and EU Method C.3. The concentration range tested in the final study was nominally 3.2 to 1000 mg/L, forming a geometric progression with a factor of 3.2, with a control (0 mg/L). Inhibition of cell growth and growth rate reduction increased with increasing concentration of diammonium persulfate from 100 mg/L upwards, resulting in 100 % inhibition and growth rate reduction at nominally 1000 mg/L. The nominal 72 -hour EC50 for growth inhibition was 136 mg/L with a 95 % confidence interval ranging from 63 to 281 mg/L. The nominal 72 -hour EC50 for growth rate reduction was 320 mg/L. The no observed effect concentration (NOEC) was 32 mg/L.

Description of key information

The acute toxicity of the Persulfate Category to aquatic algae was tested in four studies. One study was available for disodium persulfate and three for diammonium persulfate. The studies were in accordance to OECD guideline 201 and EU Method C.3. The most sensitive EC50 (72 h) value for marine water detected at 320 mg/L with a NOEC of 32 mg/L.

Key value for chemical safety assessment

EC50 for marine water algae:

320 mg/L

EC10 or NOEC for marine water algae:

32 mg/L

Additional information

The acute toxicity of the Persulfate Category to aquatic algae was tested in three studies. One study was available for disodium persulfate and three for diammonium persulfate. The marine algal growth inhibition test with diammonium persulfate revealed an EC50 (72 h) of 320 mg/L, the most sensitive value available.