Decyl dihydrogen phosphate, potassium salt

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge nitrification inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

29 March 1995

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

No data on composition, identity, phys-chem properties of test substance and testing laboratory. The study is said to be performed in line with international guideline. Not GLP. No full report, just a collection of data with a minor description of procedure. No validation with reference substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 9509 (Toxicity test for assessing the inhibition of nitrification of activated sludge microorganisms)

Deviations:

yes

Remarks:

No concentration measurements, no positive control

Principles of method if other than guideline:

No measurements of concentration, only nominal values. No positive control. No equal dose step in the concentration series.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Decyl dihydrogen phosphate, potassium salt

EC Number:

270-390-7

EC Name:

Decyl dihydrogen phosphate, potassium salt

Cas Number:

68427-32-7

Molecular formula:

C10H23O4P.xK

IUPAC Name:

potassium decyl hydrogen phosphate

Constituent 2

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

Oxidane

Test material form:

liquid

Details on test material:

Identification: Decyl dihydrogen phosphate, potassium salt (CAS# 68427-32-7)
CAS-No.: 68427-32-7
Batch: 1526886
Purity: 56%
Physical state/Appearance: Pale yellow liquid
Expiry Date: 31 March 2018
Storage Conditions: Room temperature in the dark

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Before and after incubation samples were taken from the filtered mixtures.

Test solutions

Vehicle:

not specified

Details on test solutions:

Different concentrations of the test material were prepared, but no data on procedures are available.

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

Suspendid solids concentration of the sludge was 3.29 g/L. Origin of the sludge was the Loudden treatment plant. Sludge was collected at the plant and tested the same day.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

4 h

Post exposure observation period:

None

Test conditions

Hardness:

No data

Test temperature:

22-23C

pH:

No data

Dissolved oxygen:

No data

Nominal and measured concentrations:

Nominal concentrations:
0.04% - 0.08% - 0.12% - 0.20% - 0.40%

Details on test conditions:

Different concentrations of the test material and a medium that contained ammonium were mixed with activated sludge to a concentration of suspended solids. Mixtures were incubated in a shaker for 4hours and then filtered.
A control sample (containing sludge, medium and water) was prepared and treated using the same routine as test concentrations of the substance.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

4 h

Dose descriptor:

EC50

Effect conc.:

0.26 other: %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Effect concentrations 2

Duration:

4 h

Dose descriptor:

other: EC20

Effect conc.:

0.1 other: %

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Details on results:

With increasing concentrations, a dose dependent increase in nitrification inhibition was found. A dose of 0.04% caused a reduction of 8.5%, while 0.40% caused a reduction of 73%.

Any other information on results incl. tables

Conc substance (in %)	% inhibition nitrification
0.04	8.5
0.08	17.7
0.12	21.8
0.20	36.2
0.40	73.1

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

Due to the limited information on methods and validity data it is not possible to draw reliable conclusions on the basis of the data presented in the study. However, the tested concentrations indicated a dose dependent inhibitory effect to the nitrification potential of the sludge used. The EC20 value was derived at 0.10%, while the EC50 value was concluded at 0.26%.

Executive summary:

In this study, the possible effect of Berol 38, Berol 28, Berol 522, Berol 266, Berol 226, Berol 397and Ag 6202 on the nitrification potential of activated sludge was examined. Activated sludge was obtained from Loudden treatment plant and was exposed to different concentrations of Berol 522 (0.04%-0.4%). A dose dependent inhibitory effect to the nitrification potential of the sludge used was observed. The EC20 value was derived at 0.10%, while the EC50 value was concluded at 0.26%.