1-Propanesulfonic acid, 3-(cyclohexylamino)-2-hydroxy-, sodium salt (1:1)

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2012-07-31 to 2013-05-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf in Germany.
- Preparation of inoculum for exposure: The sludge was filtrated, washed with tap water twice, then washed with and re-sus­pended in test medium. It was then aerated for >= 12 hours.
- Concentration of sludge: The dry matter was determined with 4120 mg suspended solids/litre.
- Inoculum concentration: 25 mg/L
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

ca. 48 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: see below
- Test temperature: 20.5 - 23.0 °C
- pH: approx. 7.5 (on day 28)
- pH adjusted: no
- Suspended solids concentration: 4120 mg suspended solids/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2000 mL-Schott-flasks were used as test vessels, 100 mL scrubber flasks as absorbent vessels.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aerated with purified (by activated charcoal), CO2-scrubbed, moistened air
- Measuring equipment: IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena
- Test performed in open system: yes
- Details of trap for CO2 and volatile organics: 0.25-m-NaOH

SAMPLING
- Sampling frequency: on days 0, 2, 4, 7, 9, 11, 14, 17, 22 and 29

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Positive control: yes

IDENTIFICATION AND QUANTIFICATION OF TRANSFORMATION PRODUCTS
Analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena. Each sample was measured at least in duplicate. The carbon analyser was calibrated with freshly prepared reference solutions once a week. After every start, quality control samples were measured.

Reference substance:

aniline

Preliminary study:

Not performed

Test performance:

The validity criteria were met.
- IC content of test item solution in medium: < 1 % (criterion >= 5 % of Total Carbon (TC))
- CO2 emitted by the controls: 9.7 mg/L (criterion < 70 mg/L)
- Difference within replicates: 1.1 % (Criterion >= 20 %)
- Degradation of positive control > 60 %: 14 days (=< 14 days)
- Degradation in the toxicity flask on day 14: 25 % (>= 25 %)

Key result

Parameter:

% degradation (CO2 evolution)

Value:

2.4

St. dev.:

0.42

Sampling time:

29 d

Details on results:

Within the study period of 28 days a degradation of 2.4 % was determined for the test substance. The test substance is considered to be not ready biodegradable.

Results with reference substance:

Degradation of the positive control (aniline) was determined to be 63 % after fourteen days.

Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	abiotic Control	Toxicity Control
2	0.3	0.4	0.3	0.5	-0.6	0.0	0.7	0.1
4	4.9	7.8	6.4	0.4	-2.6	-1.1	0.1	1.6
7	46.0	49.6	47.8	0.7	0.8	0.7	-0.2	11.9
9	50.3	51.6	51.0	0.2	0.5	0.3	-0.4	16.5
11	61.6	56.5	59.0	0.6	0.0	0.3	-0.5	22.2
14	66.0	59.9	62.9	0.3	-0.3	0.0	-0.6	24.7
17	69.0	63.1	66.1	0.3	-0.2	0.0	-0.3	25.6
22	76.9	76.8	76.8	1.9	0.0	1.0	-0.4	30.6
29	75.0	78.5	76.8	2.9	1.8	2.4	-0.6	35.7

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The ready biodegradability of the test item was determined according to OECD 301 B (1992). Within the study period of 28 days a degradation of 2.4 % was determined for the test substance. The test substance is considered to be not ready biodegradable.

Executive summary:

The ready biodegradability of the test item was determined according to OECD 301 B (1992) under GLP conditions. This study was performed in order to evaluate aerobic elimination and degradation potential of the test substance in a test for ready biodegradability, using a test item concentration of nominally 20 mg organic carbon/L (corresponding to 48.0 mg test substance/L). Activated sludge from a biologic sewage treatment plant was used. The chosen plant is treating mostly domestic sewage. The sludge was filtrated, washed with tap water twice, then washed with and re-suspended in test medium. It was then aerated for > 12 hours. The dry matter was determined with 4120 mg suspended solids/L. The test item in a mineral medium was inoculated and incubated under aerobic conditions in the dark. The amount of DOC in the test solution due to the inoculum was kept as low as possible compared with the amount of organic carbon due to the test item. Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A positive control (aniline) was run in parallel to check the operation of the procedures. Degradation was followed by determining the carbon dioxide produced. Measurements were taken at sufficiently frequent intervals to allow the identification of the beginning and end of biodegradation. Degradation behaviour of positive control and toxicity control was normal. The degradation of the positive control was 63 % after 14 days. Abiotic degradation was not observed. Both replicates of the test item showed very good correspondence. All validity criteria were met. Within the study period of 28 days a degradation of 2.4 % was determined for the test substance. The test substance is considered to be not ready biodegradable.

Description of key information

Biodegradation in water: screening test

The ready biodegradability of the test item was determined according to OECD 301 B (1992) (reference 5.2.1-1). Within the study period of 28 days a degradation of 2.4 % was determined for the test substance. The test substance is considered to be not ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of the test item was determined according to OECD 301 B (1992) under GLP conditions. This study was performed in order to evaluate aerobic elimination and degradation potential of the test substance in a test for ready biodegradability, using a test item concentration of nominally 20 mg organic carbon/L (corresponding to 48.0 mg test substance/L). Activated sludge from a biologic sewage treatment plant was used. The chosen plant is treating mostly domestic sewage. The sludge was filtrated, washed with tap water twice, then washed with and re-suspended in test medium. It was then aerated for > 12 hours. The dry matter was determined with 4120 mg suspended solids/L. The test item in a mineral medium was inoculated and incubated under aerobic conditions in the dark. The amount of DOC in the test solution due to the inoculum was kept as low as possible compared with the amount of organic carbon due to the test item. Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A positive control (aniline) was run in parallel to check the operation of the procedures. Degradation was followed by determining the carbon dioxide produced. Measurements were taken at sufficiently frequent intervals to allow the identification of the beginning and end of biodegradation. Degradation behaviour of positive control and toxicity control was normal. The degradation of the positive control was 63 % after 14 days. Abiotic degradation was not observed. Both replicates of the test item showed very good correspondence. All validity criteria were met. Within the study period of 28 days a degradation of 2.4 % was determined for the test substance. The test substance is considered to be not ready biodegradable.