DL-α-(aminomethyl)-p-hydroxybenzylic alcohol hydrochloride

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:

28 Jun 2018 to 29 Oct 2018

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)

Deviations:

yes

Remarks:

None of the deviations were considered to have impacted the overall integrity of the study or the interpretation of the study results and conclusions.

GLP compliance:

yes

Specific details on test material used for the study:

Identification: Octopamine hydrochloride Appearance: White to off white powder (determined by Charles River Den Bosch) Batch: D151-1710037 Test item storage: At room temperature protected from light Stable under storage conditions until: 26 October 2019 (retest date)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Source: The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
Treatment: The freshly obtained sludge was kept under continuous aeration until further treatment. Before use, the sludge was coarsely sieved (1 mm) and washed with mineral medium. After treatment the concentration of suspended solids (SS) was determined to be 3 g/L in the concentrated sludge as used for the test. The magnetically stirred sludge was used as inoculum at the amount of 3 mL per litre of mineral medium, leading to a SS concentration of 8 mg/L.
Reason for selection: The test has been accepted internationally for determining the 'ready' biodegradability of test items under aerobic conditions.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 12 mg/L

Based on:

TOC

Initial conc.:

ca. 23.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Source: The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
Treatment: The freshly obtained sludge was kept under continuous aeration until further treatment. Before use, the sludge was coarsely sieved (1 mm) and washed with mineral medium. After treatment the concentration of suspended solids (SS) was determined to be 3 g/L in the concentrated sludge as used for the test. The magnetically stirred sludge was used as inoculum at the amount of 3 mL per litre of mineral medium, leading to a SS concentration of 8 mg/L.
Reason for selection: The test has been accepted internationally for determining the 'ready' biodegradability of test items under aerobic conditions.

TEST CONDITIONS
Test duration 28 days for the inoculum blank and test item (last CO2 measurement on day 29). 14 days for the procedure and toxicity control (last CO2 measurement on day 15). During the test period, the test media were aerated and stirred continuously.
Test vessels 2 litre brown coloured glass bottles.
Milli- RO water Tap-water purified by reverse osmosis (Milli- RO) and subsequently passed over activated carbon.
Stock solutions of A) 8.50 g KH2PO4 mineral components 21.75 g K2HPO4 67.20 g Na2HPO4.12H2O 0.50 g NH4Cl dissolved in Milli- RO water and made up to 1 litre, pH 7.4 ± 0.2 B) 22.50 g MgSO4.7H2O dissolved in Milli- RO water and made up to 1 litre.
C) 36.40 g CaCl2.2H2O dissolved in Milli- RO water and made up to 1 litre. D) 0.25 g FeCl3.6H2O dissolved in Milli- RO water and made up to 1 litre.
Mineral medium 1 litre mineral medium contains: 10 mL of solution (A), 1 mL of solutions (B) to (D) and Milli- RO water.
Barium hydroxide 0.0125 M Ba(OH)2 (Boom, Meppel, The Netherlands), stored in a sealed vessel to prevent absorption of CO2 from the air.
Synthetic air (CO2 < 1 ppm)1 A mixture of oxygen (ca. 20%) and nitrogen (ca. 80%) was passed through a bottle, containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was passed through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 mL/min). Illumination The test media were excluded from light.

Preparation of Bottles
Pre-incubation medium: The day before the start of the test (day -1) mineral components, Milli- RO water (ca. 80% of final volume) and inoculum were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.
Type and number of bottles: Test suspension: containing test item and inoculum (2 bottles). Inoculum blank: containing only inoculum (2 bottles) Procedure control: containing reference item and inoculum (1 bottle). Toxicity control: containing test item, reference item and inoculum (1 bottle).
Preparation: At the start of the test (day 0), test and reference item were added to the bottles containing the microbial organisms and mineral components. The volumes of suspensions were made up to 2 litres with Milli- RO water, resulting in the mineral medium described before. Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit air line of each test bottle.

Determination of CO2
Experimental CO2 production: CO2 produced in each test bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol® ampoule), Merck, Darmstadt, Germany).

Measurements: Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until day 28, for the inoculum blank and test item. Titrations for the procedure and toxicity control were made over a period of at least 14 days. Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers were moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series. Phenolphthalein (1% solution in ethanol, Merck) was used as pH-indicator. On the penultimate day, the pH of respective test suspensions was measured and 1 mL of concentrated HCl (37%, Merck) was added to the bottles of the inoculum blank and test suspension. The bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 15 (procedure and toxicity control) and on day 29 (remaining vessels). Theoretical CO2 production The theoretical CO2 production was calculated from the molecular formula.

Measurements and Recordings
pH: At the start of the test (day 0) and on the penultimate day (day 14 for the procedure and toxicity control and day 28 for the inoculum blanks and test item), before addition of concentrated HCl. Temperature of medium Continuously in a vessel with Milli- RO water in the same room.

Reference substance:

other: Sodium acetate

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 42

Sampling time:

28 d

Details on results:

Theoretical CO2 Production
The ThCO2 of Octopamine hydrochloride was calculated to be 1.86 mg CO2/mg. The ThCO2 of sodium acetate was calculated to be 1.07 mg CO2/mg.

Biodegradation
The relative biodegradation values calculated from the measurements performed during the test period revealed 42% biodegradation of Octopamine hydrochloride (based on ThCO2), for the duplicate vessels tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met. In the toxicity control, more than 25% biodegradation occurred within 14 days (50%, based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity. Functioning of the test system was checked by testing the reference item sodium acetate, which showed a normal biodegradation curve

Monitoring of Temperature
The temperature recorded in a vessel with water in the same room varied between 22 and 23°C.

Results with reference substance:

Functioning of the test system was checked by testing the reference item sodium acetate, which showed a normal biodegradation curve.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

In conclusion, Octopamine hydrochloride was designated as not readily biodegradable.

Executive summary:

The objective of the study was to evaluate the test item Octopamine hydrochloride for its ready biodegradability in an aerobic aqueous medium with microbial activity introduced by inoculation with activated sludge. The study procedures described in this report were in compliance with the OECD guideline No. 301 B, 1992. Octopamine hydrochloride was a white to off-white powder with a purity of 99.8% (HPLC). The test item was tested in duplicate at a target concentration of 23.5 mg/L, corresponding to 12 mg TOC/L. The organic carbon content was based on the molecular formula. The Theoretical CO2 production (ThCO2) of Octopamine hydrochloride was calculated to be 1.86 mg CO2/mg. The study consisted of six bottles:  2 inoculum blanks (no test item),  2 test bottles (Octopamine hydrochloride),  1 procedure control (sodium acetate) and  1 toxicity control (Octopamine hydrochloride plus sodium acetate). Since Octopamine hydrochloride was easily soluble in water the test media were prepared using a stock solution of 1 g/L in Milli-RO water. Aliquots of 47 mL of the clear and colourless stock solution were added to the test item bottles A and B and to the toxicity control. These test bottles contained medium with microbial organisms. The volumes of suspensions were made up to 2 litres with Milli-RO water. The test solutions were continuously stirred during the test, to ensure optimal contact between the test item and the test organisms. Test duration was 28 days for the inoculum blank and test item (last CO2 measurement on day 29) and 14 days for the procedure and toxicity control (last CO2 measurement on day 15). The relative biodegradation values calculated from the measurements performed during the test period revealed 42% biodegradation of Octopamine hydrochloride (based on ThCO2), for the duplicate vessels tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met. In the toxicity control, Octopamine hydrochloride was found not to inhibit microbial activity. Since all criteria for acceptability of the test were met, this study was considered to be valid. In conclusion, Octopamine hydrochloride was designated as not readily biodegradable.

Description of key information

The relative biodegradation values calculated from the measurements performed during the test period revealed 42% biodegradation of Octopamine hydrochloride (based on ThCO2), for the duplicate vessels tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met. Octopamine hydrochloride was designated as not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater