Benzoic acid, 3-amino-5-[[(2,3-dihydroxypropyl)amino]carbonyl]-2,4,6-triiodo-

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:

April 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN 38412, L9

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

rac-5-Amino-N-(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamic acid

EC Number:

601-093-6

Cas Number:

111453-32-8

Molecular formula:

C11 H11 I3 N2 O5

IUPAC Name:

rac-5-Amino-N-(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamic acid

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances):
- Method: For the definitive test, a stock suspension of 10.0015 g/L was prepared by dissolving the test substance in test medium at room temperature. This solution was neutralized to pH-7 with 1 M NaOH.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Source: Culture Collection of Algae and Protozoa, Ambleside, Cumbria. United Kingdom on 1990.11.16; This strain was malntained on sloped agar tubes In the light at room temperature tor 2 weeks. After this perlod the sloped agar tubes are stored at 4 °C until required.
- Age of inoculum (at test initiation): fresh

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

23.4 - 24.7 °C

pH:

8.3 - 9.3

Nominal and measured concentrations:

Nominal: 0, 10, 100, 1000, 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL Erlenmayer flasks (sterilized)
- Initial cells density: 2.0 E+04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous light
- Light intensity and quality: 60 - 120 µEm-2*s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Cell concentrations were determined photometrically (UV/VIS, 436 nm)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Results with reference substance (positive control):

ErC50 (72 h): 1.00 mg/L
EbC50 (72 h): 0.37 mg/L

Reported statistics and error estimates:

The EC10,50 values were computed from the best fitted line (Ieast-squares method) through the points given by the probit of the percentage of inhibition and the logarithm of the concentration of the test substance. The EC50 value calculated for the area under the growth curve Is termed EbC50 (0-72 h), whereas the EC50 value calculated for the specific growth rate is termed ErC50. Confidence limits were computed on the basis of Fleller's theorem (4.2). All computations were performed using the Akzo programme ‘AIgal’ (version 3.3) made In SAS (4.3).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The ErC50 (72 h) of Tamip monoamid (ZK39.211) to green algae was higher than 10 g/L.

Executive summary:

Desmodesmus subspicatus were incubated over a period of 72 h to ZK 39.211 at concentrations from 0.01 - 10 g/L. The cell density was determined by extrapolating the measured chlorophyll concentration. Chlorophyll was analysed at 0, 24, 48 and 72 hours by means of a spectrophotometer and values were recalculated for cell density by a calibration factor. Biomass and specific growth rate was calculated. Therefore, no values tor the concentrations of ZK39211 (TAMIP-monoamide) leading to a 10% or 50% reduction in specific growth rate (ErC₁₀ or ErC₅₀) or to a  10% or 50% reduction in growth over the 72-hour period [EbC10 or EbC50 (0-72 hours)] could be calculated. The reference compound potassium dichromate had an ErC₅₀ and EbC₅₀ of 1.0 and 0.37 mg/L, respectively.

The cell density was inhibited up to 16% at the highest concentration. Therefore, the EC50 (72 h) was higher than 10 g/L.