2-[3-(4-propyl-heptyl)-morpholin-4-yl]-ethanol hydrochloride

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 03, 2016 - October 17, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Determine the ready biodegradability of test item.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-[3-(4-propylheptyl)morpholin-4-yl]ethan-1-ol hydrochloride

EC Number:

688-947-1

Cas Number:

98092-92-3

Molecular formula:

C16H34NClO2

IUPAC Name:

2-[3-(4-propylheptyl)morpholin-4-yl]ethan-1-ol hydrochloride

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Test item name: Delmopinolo HCl
Batch number: 2510468
Internal number: 2929564-001
Chemical name 2-[3-(4-propylheptyl)-4-morpholinyl) ethanol hydrochloride (1:1)
Purity : 100.3% w/w

The test item is stored at room temperature without particular precaution to avoid the light exposure following Test Substance Data Sheet (TSDS) supplied by the Sponsor.
Stability under
storage conditions: protect from moisture

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: Aerobic activated sludge from BRIANZACQUE civil wastewater treatment plant.

Details on inoculum:

Since the test item was fully soluble in water, a concentrated stock solution at 100.0 mg/L was prepared by weighing 0.0500 g of test item in 500 mL of mineral medium. The proper volume was dosed in the test flasks to obtain the final concentrations of 35 mg/L of test item making to a final volume of 250 mL or 150 mL (based on setting scale) with test medium. Moreover, stock solutions (10 g/L) of reference item Sodium Benzoate and sterilizing agent HgCl2 were prepared and an appropriate aliquot of the stock solution was added to the test medium (final volume: 250 mL or 150 mL ) in the test flasks to obtain a final concentration of
100 mg/L. Activated sludge was added to each flask (with the exception of the abiotic control) before incubation. Finally, the test flasks, containing stir bars covered with teflon, were kept under continuous stirring by the means of a magnetic stirrer for the 28-days test period.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 35 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Experimental design
The assay on test item was carried out in parallel with the following bottles:
- a known ready biodegradable reference item (one replicate), Sodium Benzoate, at 100 mg/L;
- two inoculum control replicates (blank);
- two test item replicates at 35 mg/L concentration;
- one abiotic control containing the test item at 35 mg/L and a sterilizing agent (HgCl2) at 100 mg/L (without inoculum);
- one toxicity control, containing the test item at 35 mg/L and reference item at 100 mg/L.
BOD flasks of 500 mL capacity, equipped with pressure sensors fitted on the bottle mouth, were used as test units.
The method is based on an electro-chemical analyses process. The biodegradation process consumes the dissolved oxygen in liquid and generates CO2. Evolved carbon dioxide is
adsorbed by potassium hydroxide and the total pressure decreases in the test flasks. The pressure decrease is detected and converted into an electrical signal by means of an
electrode type manometer.

Test medium
The test medium was prepared according to the testing guidelines: salts of analytical grade were dissolved in purified water to obtain the stock solutions.
In order to allow the storage of solution, one drop of concentrated HCl was added. 10 mL of stock solution a) and 1 mL of stock solutions b), c) and d) were added to 800 mL of
purified water, then made up to 1000 mL with purified water. The pH of test medium was 7.45 (mean value between two blank bottles), so adjustment with a diluted hydrochloric acid or sodium hydroxide solution, before making up to volume, was not needed.

Test solutions
Since the test item was fully soluble in water, a concentrated stock solution at 100.0 mg/L was prepared by weighing 0.0500 g of test item in 500 mL of mineral medium. The proper volume was dosed in the test flasks to obtain the final concentrations of 35 mg/L of test item making to a final volume of 250 mL or 150 mL (based on setting scale) with test medium. Moreover, stock solutions (10 g/L) of reference item Sodium Benzoate and sterilizing agent HgCl2 were prepared and an appropriate aliquot of the stock solution was added to the test medium (final volume: 250 mL or 150 mL ) in the test flasks to obtain a final concentration of 100 mg/L. Activated sludge was added to each flask (with the exception of the abiotic control) before incubation. Finally, the test flasks, containing stir bars covered with teflon, were kept under continuous stirring by the means of a magnetic stirrer for the 28-days test period.

Temperature:
The incubation temperature was continuously monitored during the course of the study by means of a data logger. It was in the range 22.3 – 22.4 °C with a mean value of 22.3 °C and a standard deviation of 0.01 °C. The temperature range recommended by OECD guideline is 22 ± 2 °C, this range was corrected according to the data logger precision, therefore the range to be considered for the test was 20.5 – 23.5 °C while the recorded temperature values were corrected according to the correction factor, Cw (0.0 °C).
The recorded temperature values during the test period were within the recommended range and the maximum deviation was lower than 1 °C, as recommended by the guideline.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 0

Sampling time:

28 d

Details on results:

The tested concentration was 35 mg/L (corresponding to 89.25 mg ThOD/L).
All reported results are related to the nominal concentration of test item, since the test concentrations were not measured during the test.

The biodegradation was followed by measuring the oxygen uptake (mg/L) of the test item under defined conditions by the means of a manometric method and calculating from these values the BOD (Biochemical Oxygen Demand).

The following information are reported in attached in the section illustration:
- The oxygen concentrations measured in inoculum control bottles;
- The oxygen concentrations measured in test item bottles, the corresponding BOD values and percentage biodegradation;
- The oxygen concentrations measured in reference item and toxicity control bottles, the corresponding BOD values and percentage biodegradation;
- The oxygen concentrations measured in the abiotic control bottle, the corresponding BOD values and percentage biodegradation;
- The ThODNH3 value (Theoretical Oxygen Demand without nitrification process) was calculated to be equal to 1.67 mg O2/mg for reference item, Sodium Benzoate. While for the test item the ThODNO3 value (Theoretical Oxygen Demand with nitrification process) was assessed to be 2.55 mg O2/mg.
These values, 1.67 mg O2/mg for reference item and 2.55 mg O2/mg for the test item, were used to calculate the % biodegradation. Nitrate and nitrite concentration was measured at the start and at the test end. During the test period only a slightly nitrite formation was observed. The oxygen amount used in oxidising ammonium process was determined to be equal to 0.523 mg O2.

The test item, Delmopinolo HCl, was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test, since no biodegradation was observed during the test period. No significant degradation was observed in the abiotic control.

The toxicity control clearly showed that the test item does not cause inhibitory effect on the microorganisms activity at the tested concentration. Actually, the toxicity control exceeded the 25 % pass level after eight days of exposure (25.5 %). The reference item exceeded the biodegradation pass level (60%) after four days (63.5 %), within the range fixed by OECD guideline (first 14 days).

BOD5 / COD results

BOD5 / COD

Key result

Parameter:

BOD5

Value:

ca. 0 other: mg/L

Results with reference substance:

The reference substance is considered to be readily biodegradable (BOD5 is 107 mg/L, BOD 1.0600 and % biodegradation >60%)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item, Delmopinolo HCl was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test, since no biodegradation was reached during the test period. No significant degradation was observed in the abiotic control. Moreover, the test item showed no inhibitory effects on the microorganism activity at the tested concentration, as demonstrated by the biodegradation percentage in the toxicity control exceeding the 25 % pass level after eight days of exposure (25.5 %).

Executive summary:

The test item, Delmopinolo HCl was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test.