Zinc bis[O,O-bis(2-ethylhexyl)] bis(dithiophosphate)

Toxicity to microorganisms

Administrative data

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998-03-09 to 1998-03-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN EN ISO 10712 Pseudomonas putida growth inhibition test

Deviations:

yes

Remarks:

Start turbidity by bacteria was 5 FNU instead of 10

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Zinc bis[O,O-bis(2-ethylhexyl)] bis(dithiophosphate)

EC Number:

224-235-5

EC Name:

Zinc bis[O,O-bis(2-ethylhexyl)] bis(dithiophosphate)

Cas Number:

4259-15-8

Molecular formula:

Too complex

IUPAC Name:

1-Hexanol, 2-ethyl-, O,O-diester with phosphorodithioic acid, zinc salt

Details on test material:

- Analytical purity: 81%
- Lot/batch No.: 94008624

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: 1 g test substance has been stirred for 3 days in 1 L deionized water. The test substance did not dissolve completely. Therefore a separation of the water dissolved part has been carried out by centrifugation (10 minutes, 6.400 g). The concentration of dissolved test substance (in deionized water) has been determined by DOC analysis; DOC of dissolved test substance was 258 mg/L. In addition, the C-content of the test substance has been determined by TC analysis to be 0.275 g C/g test substance. From this data a test substance concentration of 938 mg/L in the stock solution has been calculated. The stock solution was diluted by a factor of 2 to obtain the test concentrations.

Test organisms

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: The test organism Pseudomonas putida, MIGULA, strain Berlin 33/2 (DSM 50026) originated from German collection of microorganismus (DSM)
- Initial biomass concentration: start turbidity by bacteria was 5 Formaline nephelometric units (FNU)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test conditions

Test temperature:

23 +/- 1 °C

pH:

-In test vessels, pH ranged from 6.8-7.2 at test start and from 3.5 - 4.5 at test end
-In the control vessels, pH was determined to be 7.2 at test start and between 6.3 and 6.5 at test end

Nominal and measured concentrations:

59, 118, 235 and 469 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: The fill volume was 10 mL
- No. of vessels per concentration (replicates): it is not specified in the report, whether 3 replicates per concentration were tested or whether 3 measurement have been done in one replicate
- No. of vessels per control (replicates): not specified, either 8 replicates per control were tested or one replicate have been evaluated 8 times.


TEST MEDIUM / WATER PARAMETERS
- Total organic carbon: 0.275 g C/g


OTHER TEST CONDITIONS
- Adjustment of pH: yes, method not stated
- Shaking velocity: 150 rpm


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): optical density, Formaline nephelometric unit (FNU) determination at a wavelength of 436 nm


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

380 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Effect concentrations 2

Duration:

16 h

Dose descriptor:

EC0

Effect conc.:

200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Results with reference substance (positive control):

Results with reference substance valid? yes
- Relevant effect levels: EC50 = 19 mg/L
- Other: EC10 = 13 mg/L

Reported statistics and error estimates:

ECx values were determined by graphic evaluation

Any other information on results incl. tables

Optical density measurements

a) test substance Test substance concentration Dilution series factor (f=2) of stock solution Optical density (436 nm) 1 2 3 469 2 0.53 0.584 0.548 235 4 1.54 1.61 1.57 118 8 1.59 1.57 1.63 59 16 1.64 1.68 1.65   b) control Control Optical density (436 nm) 1 1.60   2 1.58   3 1.35   4 1.62   5 1.58   6 1.61   7 1.59   8 1.52   mean 1.56      Growth inhibition Test substance concentration FNU (436 nm) Inhibition (%) 1 2 3 mean 469 133 146 137 139 64 235 385 403 393 327 16 118 398 393 408 400 0 59 410 420 413 414 0 Control 400, 395, 338, 405, 395, 403, 398, 380 389   The test is considered as valid as the validity criteria were met (multiplication factor of the inoculum in the controls > 60, EC50 of the reference substance 3,5 -dichlorophenol 10-30 mg/L).