Toluene-4-sulphonohydrazide

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Following GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

22 July, 2010

Deviations:

no

Principles of method if other than guideline:

not relevant

GLP compliance:

yes

Specific details on test material used for the study:

Identity: 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH)
CAS No.: 80-51-3
EC No.: 201-286-1
KIT Code No.: K-5450
Lot No.: 201512001
Appearance: White fine powder
Purity: 99.5~100%
Expiry date: December, 2016
Storage conditions: Room temperature / Protect from moisture and light

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

to be decided

Test organisms (species):

activated sludge

Details on inoculum:

Activated sludge was collected from Nivå wastewater treatment plant on 13 November 2017. After addition of 75 mL synthetic sewage to 7-8 L sludge, the sludge were stored overnight with aeration at room temperature. Sludge was separated from the water phase by centrifugation (10 min. at approx. 1,500 rpm - approx. 15,000 m/sec2). Then the sludge was re-suspended in tap water and the washing procedure was repeated. The sludge was sieved through a 1-mm sieve and finally re-suspended in tap water. The concentration of the suspended solids (SS) in the re-suspended sludge was determined as descirbed in DS/EN 872 to be 23.4 g SS/L. The sludge was stored at 5oC overnight. On the test day, the activated sludge was aerated until use.

A preliminary respiration rate of the sludge, measured in a mixture consisting of 10% sludge, synthetic seage medium and Milli-Q water, was estimated to be 64 mg O2/L/hr (corresponding to 27 mg O2/g SS/hr). The respiration rate fulfilled the validity criterion af >20 mg O2/g SS/hr).

The final sludge concentrations in the test mixtures were 2.26 - 2.47 gSS/L.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

180 min

Post exposure observation period:

no

Hardness:

No data

Test temperature:

21 (20.5-21.8) oC

pH:

7.5 ± 0.5 (start of test); 7.7 -7.9 (at completed test)

Dissolved oxygen:

3.7-7.0 (controls, 30 minutes)
2.5-7.0 (controls, 180 minutes)

Salinity:

NA

Conductivity:

NA

Nominal and measured concentrations:

Nominal

Details on test conditions:

Please refer to information stated in the section above

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

911 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Confidence interval: 801-1069

Key result

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

244 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Confidence interval: 201-283

Key result

Duration:

180 min

Dose descriptor:

EC50

Effect conc.:

641 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Confidence interval: 593-697

Key result

Duration:

180 min

Dose descriptor:

other: EC20

Effect conc.:

186 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Confidence interval: 164-207

Results with reference substance (positive control):

The results obtained with the reference item 3,5-dichlorophenol, showed an EC50 of 10.7 mg/L (30 min) and 6.7 mg/L (180 min). The EC50 was within the 2 to 25 mg/L range, and it was considered acceptable for the test

No data

Validity criteria fulfilled:

yes

Conclusions:

30 min EC50 = 911 mg/L (respiration rate)
30 min EC20 = 244 mg/L (respiration rate)
180 min EC50 = 641 mg/L (respiration rate)
180 min EC20 = 186 mg/L (respiration rate)

Executive summary:

The test item was tested according to OECD Guideline no 209: Activated Sludge, Respiration Inhibition Test. The study was conducted according to GLP.

Resulting EC50 = 911 mg/L (30 min), EC20 = 244 mg/L (30 min), EC50 = 641 mg/L (180 min) and EC20=186 mg/L (180 min).

Description of key information

The test item was tested according to OECD Guideline no 209: Activated Sludge, Respiration Inhibition Test. The study was conducted according to GLP.

Resulting EC50 = 911 mg/L (30 min), EC20 = 244 mg/L (30 min), EC50 = 641 mg/L (180 min) and EC20=186 mg/L (180 min).

Key value for chemical safety assessment

EC50 for microorganisms:

641 mg/L