5-(4-hydroxyphenyl)imidazolidine-2,4-dione

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

end on XXX

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study performed according to OECD guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

5-(4-hydroxyphenyl)imidazolidine-2,4-dione

EC Number:

219-340-8

EC Name:

5-(4-hydroxyphenyl)imidazolidine-2,4-dione

Cas Number:

2420-17-9

Molecular formula:

C9H8N2O3

IUPAC Name:

5-(4-hydroxyphenyl)imidazolidine-2,4-dione

Details on test material:

- Name of test material (as cited in study report): p-Hydroxy-phenylhydantoin
- Substance type: monoconstituent substance
- Physical state: powder
- Stability under test conditions: will be tested within this study (see analytical section)
- Storage condition of test material: at room temperature, protected from light

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 1.00, 2.20, 4.84, 10.65, 23.43 mg/L
- Sampling method: data not available
- Sample storage conditions before analysis: measured immediately after sampling

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:
The test item was applied as follows: stock solutions were made in ultrapure water. Aliquots of the stock solutions were made up with ultrapure water, „intermediate dilution“ and algal inoculum (or diluted „intermediate dilution“) to give 50 mL of final volume.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: Desmodesmus subspicatus CHODAT
- Source: Origin: Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen [SAG], Strain-No. 86.81
- Age of inoculum: two days prior to starting the test, a pre-culture was inoculated using the algal stock culture
- Method of cultivation: the algae are cultivated under aseptic conditions.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Test conditions

Hardness:

data not available

Test temperature:

The mean temperature was 24.5°C, and the range was 24.2 to 24.9°C.

pH:

t0: 8.34 (control) and 8.15 (23.43 mg/L)
t72: 9.41 (control) and 8.43 (23.43 mg/L)

Dissolved oxygen:

data not available

Salinity:

not applicable (freashwater)

Nominal and measured concentrations:

nominal: 0, 1.00, 2.20, 4.84, 10.65, 23.43 mg/L
measured (at t0): 0, 0.980, 2.130, 4.780, 10.220, 21.070 mg/L
measured (at t72): 0, 0.780, 1.930, 4.090, 9.200, 19.220 mg/L
geom. mean of t0 vs. t72h: 0.87, 2.03, 4.42, 9.70, 20.10 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL-glass-cylinders, heat sterilized
- Type: closed (the test solutions were covered with a lid made of plexiglass which had been previously sterilized by treatment with ethanol (~70%)
- Fill volume: 50 mL
- Aeration: in order to assure the input of CO2, the test solutions were stirred by means of a magnetic stirrer for the duration of 15 minutes per hour.
- Initial cells density: 2.64*10E3
- Control end cells density: 6.00*10E5
- No. of vessels per concentration (replicates): 7
- No. of vessels per control (replicates): 7

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
The mineral nutrient medium was prepared from three stock solutions (Mineral Nutrient Salts, Fe-Complex and Trace Elements) and NaHCO3.
The medium was prepared in deionised water and autoclaved or sterilized by ultrafiltration.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: constant light
- Light intensity and quality: illumination rate of >=120 μE/m2s ([~8000 Lux]

EFFECT PARAMETERS MEASURED :
The increase in biomass was determined using a spectrophotometer after 24.5, 48, and 72 h. As a measure for the biomass the absorbance of the test solutions measured at 578 nm was used.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
- Range finding study
- Test concentrations: 0, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: the inhibition of the growth rate was 0.8, 34 and 95.3%, respectively.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.54 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 4.22 - 6.68 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

10.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 8.72 - 11.36 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

31.85 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 26.66 - 41.15 mg/L

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

9.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.42 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

7.89 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 7.09 - 8.69 mg/L

Details on results:

- Exponential growth in the control: yes

Results with reference substance (positive control):

not determined

Reported statistics and error estimates:

The inhibition values for yield and the growth rates of the algae as well as the statistical calculations were done according to the Guideline using the commercial computer program ToxRatPro Version 2.10.

Any other information on results incl. tables

Table 1 : Cell numbers (Main test)

time	T0	T24h	T48h	T72h
Control	2.64*10^3	1.72*10^4	1.33*10^5	6.00*10^5
1.00 mg/L	2.64*10^3	1.83*10^4	1.52*10^5	6.76*10^5
2.20 mg/L	2.64*10^3	8.37*10^3	7.74*10^4	4.81*10^5
4.84 mg/L	2.64*10^3	1.86*10^4	1.48*10^5	6.16*10^5
10.65 mg/L	2.64*10^3	1.86*10^4	8.88*10^4	1.50*10^5
23.43 mg/L	2.64*10^3	2.89*10^4	1.02*10^5	9.43*10^5

 

Table 2: Inhibition Values (Main Test)

NominalConcen­tra­tion of the Test Item [mg/L]	Growth Rates (day^-1)	Inhibition of the Growth Rate after 72h [%]	Yield after 72h^1)	Inhibition of the Yield after 72h [%]
Control (0)	1.80	-	5.96*10^5	-
1.00	1.84	-2.3	6.73*10^5	-12.9
2.20	1.73	4.1	4.78*10^5	19.8
4.84	1.81	-0.6	6.14*10^5	-2.9
10.65	1.33	25.9	1.47*10^5	75.3
23.43	1.18	34.4	9.16*10^4	84.6

 

¹⁾Yield = Cell number at time t_72h– cell number at time t₀

 

Table 3: Concentrations of the test item during Incubation

Nominal Concentration [mg/L]	Measured Values t0h, net-Blank [mg/L]	Measured Values t72h, net-Blank [mg/L]	geom. Mean of t0vs. t72h [mg/L]
1.00	0.98	0.78	0.87
2.20	2.13	1.93	2.03
4.84	4.78	4.09	4.42
10.65	10.22	9.20	9.70
23.43	21.07	19.22	20.10

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

72h NOErC = 4.42 mg/L
72h ECr50 = 31.85 mg/L

Executive summary:

The chronic toxic effect of p-Hydroxy-phenylhydantoin was investigated by determination of the inhibition of the growth rate of the algae and the yield during the exposure period of 72 h (OECD 201, GLP). The test item was tested at 0, 1.00, 2.20, 4.84, 10.65, 23.43 mg/L (nominal concentrations). As a conclusion of the analytical part of this study, recoveries of the concentrations determined after 72h were > 80% of those determined at t₀(with the exception of the lowest concentration of 1 mg/L), and therefore the effective concentrations are based on the measured concentrations.

From the results of the main test, toxic effects were determined with the following values:

Yield (0 - 72 h):

-         EC10 =4.67 mg/L

-         EC20= 5.59 mg/L

-         EC50 = 7.89 mg/L

-         LOEC=2.03 mg/L

-         NOEC = 0.87 mg/L

                                                        

Growth rate (0 - 72 h): 

-         EC10 = 5.54 mg/L

-         EC20= 10.10 mg/L

-         EC50 = 31.85 mg/L

-         LOEC = 9.70 mg/L

-         NOEC= 4.42 mg/L

 

The test is considered valid as all conditions for validity were met.