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Toxicity to microorganisms

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Description of key information

KS-235 exhibited no respiration inhibition and no dose response was observed. The definitive test was not required and was therefore not 
performed. KS-235 also demonstrated no abiotic response.

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

- KS-235: Assessment of Ready Biodegradability; CO2 Evolution Test

Table 3: Oxygen Consumption Rates and Percentage Inhibition from Preliminary Investigational Work Using the Activated Sludge Respiration Inhibition Test (OECD 209) Method

Nominal Concentration

O2 Consumption Rates (mg O2/l/min)

% Inhibition

Control

R1

0.48

-

R2

0.39

-

KS-235

5 mg C/l

0.42

3

10 mg C/l

0.40

8

20 mg C/l

0.41

6

3,5 dichlorophenol

3.2 mg/l

0.44

[1]

32 mg/l

0.06

86

 

[increase in respiration rates as compared to the controls]

R1 - R2 = Replicates 1 and 2

- The test material did not inhibit the respiration of sewage sludge micro-organisms at the concentration employed in the test

- An evaluation of the effect of KS-235 on the respiration rate of activated sludge - Preliminary test

Discussion: The study was conducted according to the test guideline. KS-235 exhibited no respiration inhibition and no dose response was observed. The definitive test was not required and was, therefore, not performed. KS-235 also demonstrated no abiotic response. The 3-hour EC50 of KS-235 to activated sludge respiration inhibition was determined to be >1000mg/l during the preliminary study.

3 hour exposure period

ECxvalues (mg/l)

EC20

EC50

EC80

KS-235

>1000

>1000

>1000

3,5-DCP (Reference)

1.20 (1.16 - 1.24)

6.98 (6.658 - 7.306)

>18