polymeric zinc propylenebis(dithiocarbamate);propineb (ISO)

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:

2011/07/08 to 2011/08/31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

It was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“ (2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

The activated sludge was taken from the aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal, Germany). The sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant. An aliquot of the wet sludge was dried in order to determine the wet weight / dry weight ratio of the sludge and to prepare a stock suspension (activated sludge) of 3 g dw/L. The calculated amount of sludge, needed to achieve 300 mL of this stock suspension, was dissolved in mineral medium and then filled up to a defined end volume. Before use, the inoculum was stored for two days at room temperature under continuous shaking with aeration.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test volume : 250 mL
Test apparatus : OxiTopControl System (WTW)
Mixing : 1 magnetic stirrer per test vessel
Incubation time : 28 days
Incubation temperature : 22 ± 1 °C

A suspension of 100 mg/L test item in a mineral medium, equalling to 50-100 mg ThOD or COD/L as the nominal sole source of organic carbon, was stirred in a closed flask and inoculated at a constant temperature (22 ± 1 °C) for up to 28 days under aerobic conditions in the dark.

The consumption of oxygen (BOD) was determined by measuring the drop in pressure in the automated respirometer flasks. Evolved carbon dioxide was absorbed in sodium hydroxide. The amount of oxygen taken up by the test item (corrected for uptake by blank inoculum, run in parallel) was expressed as a percentage of chemical oxygen demand (COD).

The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures. A toxicity control (test item and reference compound mixed) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms.

Degradation was followed by the determination of oxygen uptake and measurements were taken at frequent intervals to allow the identification of the beginning and end of biodegradation and the slope of the biodegradation curve. The test lasted for 28 days. Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, determinations of reference compound were carried out in duplicate and of test item and inoculum blank in triplicate.

The oxygen uptake was calculated from the readings taken at regular and frequent intervals, using the method given by the manufacturer of the equipment. At the end of incubation, the pH was measured in the flasks.

Reference substance:

other: sodium benzoate

Key result

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

7 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

14 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

21 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

28 d

Parameter:

COD

Value:

1.658 other: mg O2/mg

Results with reference substance:

The reference compound sodium benzoate showed 89 % degradation after 14 days.
Theoretical oxygen demand NH3: 1.665 mg O2/mg

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Propineb is considered to be "Not Readily Biodegradable".
However, it should be considered that the oligomer Propineb decomposes immediately in aqueous solution. This standardized test measures the complete mineralization of the transformation products to carbon dioxide at a high dose rate.

Executive summary:

A study was performed to assess the ready biodegradability of Propineb.
The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992). A suspension of Propineb in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations.

Propineb showed:
1 % degradation after 7 days
0 % degradation after 14 days
0 % degradation after 21 days
0 % degradation after 28 days

Therefore, Propineb is considered to be “Not Readily Biodegradable“.
The reference compound sodium benzoate showed 89 % degradation after 14 days.

Description of key information

A suspension of Propineb in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations. The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).

Propineb showed:
1 % degradation after 7 days
0 % degradation after 14 days
0 % degradation after 21 days
0 % degradation after 28 days

Propineb is considered to be “Not Readily Biodegradable“.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

other: Mineral medium (activated sludge)