Diamminediisocyanatozinc

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:

April and May 1986.

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)

Version / remarks:

EEC directive 84/449/EEC

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

not specified

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Range finding test
A range finding test preceded the definitive assay. Five concentrations of the test item were prepared from 0.1 mg/L to 1000 mg/l.

Definitive Assay
For the second assay, 5 concentrations of the test item were prepared as follows: 0.65 mg/L, 0.313 mg/L, 0.156 mg/L, 0.078 mg/L and 0.039 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Daphnids were obtained from a continuous laboratory culture of Daphnia magna.

ACCLIMATION:
- Acclimation period: The cultivation of the daphnia is performed in a way that the animals are transferred in new test medium at an interval 24 h prior to test
- Type and amount of food: Chlorella sorokiniana

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
- Daphnias used for the test are not older than 24 hr. Therefore, in every case, daphnia are transferred into fresh medium one day before starting of the daphnia test in order to get daphnia for the test younger than 24 hr.
- 24 h prior to the test, egg bearing females were transferred by pipette to fresh EPA soft water. Emerged, 1st instar daphnids (6-24 h old), produced by diploid parthenogenesis, were removed for the test.

- Type and amount of food: Chlorella sorokiniana

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 ± 1°C

pH:

6.35 - 7.08 during definitive main test (assay 1: 6.59-7.08; assay 2 6.35-6.94 at zerotime)
assay 2: 7.06-7.47 at 48 h

Dissolved oxygen:

81-99% during definitive main test (assay 1: 89-99%; assay 2 81-87% at zerotime)
assay 2: 70-79% at 48 h

Nominal and measured concentrations:

Nominal: 0, 0.039, 0.078, 0.156, 0.313, 0.625 mg/L
Found (t48h): 0.097, 0.069, 0.095, 0.095, 0.138 , 0.141mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: 450mL, glass
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of daphnia per replicate: 10
- Aeration: static

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted EPA soft water was used. Water was vigorously aerated for 3 hrs prior to the
test but not during the test.

TEST CONCENTRATIONS
- Range finding study:
Five concentrations of the test item were prepared from 0.1 mg/L to 1000 mg/L. Aliquots of each solution (250 mL) were placed in duplicate 400 mL capacity glass beakers and 5 daphnids transferred to each.
- Test concentrations: 0.625, 0.313, 0.156, 0.078, 0.039 and 0 mg/L

OTHER TEST CONDITIONS
- Photoperiod: 16 hr of light and 8 hr of darkness
- pH and oxygen concentrations were determined in each test vessel during the definitive assays, at zero time, and after 48 h for the second assay only

Reference substance (positive control):

not specified

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

0.195 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.058 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- In water, the test item is rapidly hydrolysed leading to the formation of zinc salts (predominantly zinc oxide) with the quantitative release of ammonia. Attempts were made to measure ammonia-N by a colorimetric assay, however concentrations were generally too low to derive reliable results. -

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Limit test: no
- Dose-response test: yes

EC50 values from statistical analysis using the Weil method

Time interval	EC50 (mg/L)	95% confidence intervals
24 h	0.195	0.128-0.297
48 h	0.058	0.047-0.072

Validity criteria fulfilled:

yes

Conclusions:

The study was performed according to OECD TG 202 without deviations, the results were so obtained via a scientifically reasonable method. Hence, there is no doubt that the obtained results are not reliable:
The following EC-values were determined accordingly after 48 hours:
Mobility:
after 24 h: EC50 = 0.195 mg/L
after 48 h: EC50= 0.058 mg/l

Based on these results, the test item needs to be classified as aquatic toxic 1 (acute and chronic) to the aquatic environment.

Executive summary:

The 48-hr-acute toxicity of the test item to daphnia magna was studied under static conditions. Test species were exposed to control and test chemical at nominal concentration of 0.625, 0.313, 0.156, 0.078, 0.039 and 0 mg/L for 48-hr.  Immobilization and sublethal effects were observed test termination. The 48 – hour EC₅₀ was 0.058 mg/L with a 95% confidence interval of 0.047-0.072 mg/L.

 

Based on these results, the test item needs to be classified as aquatic toxic 1 (acute and chronic) to the aquatic environment. 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): less than 24 h

Test Type (Static): 

EC50:  0.058 mg/L               95% C.I.: 0.047-0.072 mg/L. 

Description of key information

Acute toxicity to aquatic invertebrates: EC₅₀ (48h) = 0.058 mg/L, based on immobilisation, for Daphnia magna (OECD 202, GLP, static)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.058 mg/L

Additional information

Based on these results, the test item needs to be classified as aquatic toxic 1 (acute and chronic) to the aquatic environment.