Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

Phototransformation in water

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988-08-10 to 1988-09-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Study type:

other: Direct and indirect photolysis

Qualifier:

according to guideline

Guideline:

EPA Guideline Subdivision N 161-2 (Photodegradation Studies in Water)

Principles of method if other than guideline:

The test substance was exposed to a xenon light source for 30 days; controls were kept in the dark for 30 days.

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No information provided

Radiolabelling:

yes

Analytical method:

other: LSC and Radio-TLC

Details on sampling:

The test item was used at a nominal concentration of 10 µg/mL and was conducted at 25°C in aqueous solution buffered at pH 7.
Samples of non-sensitized and sensitized solutions were removed for analysis after 0, 1.03, 2.02, 7.03, 14.0, 21.0 and 29.9 days.

Buffers:

Definitive test buffer solution
Millipore water (pre-filtered through a 0.22 micron filter) was used to prepare the pH 7 buffer solution for this study. The buffered solution was prepared by adding 329 ml of 0.2M hydrochloric acid solution to 350 ml of 0.2M tris(hydroxymethyl)amino methane. The solution was made to a volume of 1400 ml with pre-filtered Millipore water. The pH of the buffer solution was confirmed as being 7.00 using a suitable pH meter. The buffer was autoclaved for 30 minutes at 121°C and 15 psi.

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

>= 290 - <= 750

Details on light source:

- Emission wavelength spectrum: 290mn to 750nm
- Relative light intensity based on intensity of sunlight: Approximately one-half the intensity of the sun
- Duration of light/darkness: 30 days light exposure.

Type of sensitiser:

other: acetone

Details on sensitiser:

No information provided.

Concentration of sensitiser:

ca. 1 other: %

Details on test conditions:

A study using 14C-Didecyldimethylammonium Chloride (DDAC) at a nominal concentration of 10 µg/ml was conducted at 25°C in aqueous solution buffered at pH 7. The test substance was exposed to a xenon arc light source for 30 days; controls were kept in the dark for 30 days.

Duration:

30 d

Temp.:

25 °C

Initial conc. measured:

10 other: µg/ml

Reference substance:

not specified

Dark controls:

yes

Computational methods:

No information provided.

Preliminary study:

At a nominal DDAC concentration of 10 µg/mL, it was found that the test material does not absorb significantly to glassware (silanised or non-silanised). Results from the preliminary study indicated that after 14.0 days of exposure, 93.1% radioactivity remained as parent in the non-sensitised system and 94.5% in the sensitised system. Based on these results, a 30 day exposure period was chosen for the definitive study.

Test performance:

Direct photolysis:
Half-life was not determined since no significant degradation of the test substance was detected during the 30-day evaluation period.
No detectable degradation occurred during the 30-day test period.

Indirect photolysis:
Half-life was 227 days (light, exposed) and 432 days (dark, exposed)
Approximately 7% degradation over a period of 30 days when exposed to light. Little or no degradation occurred in the presence of acetone without exposure to the light source.
Rate constant: 0.00304 days-1 (light, exposed)/ 0.00160 days-1 (dark, exposed)
Breakdown products: Yes, only in the presence of a photosensitiser when exposed to light. Essentially all of the 14C-moiety not present as parent compound was found in a single degradate.

Key result

% Degr.:

7

Sampling time:

30 d

Test condition:

In the presence of the photosensitiser when exposed to the light source.

Rate constant (for indirect photolysis):

0.003 other: days-1

Predicted environmental photolytic half-life:

227 days (light, exposed)
432 days (dark, exposed)

Transformation products:

yes

No.:

#1

Details on results:

Little or no degradation occurred in the presence of acetone without exposure to the light source.

The sensitised exposed samples also show a decrease in pH over time (pH 7 to 6 after 30 days). This change was not considered to be significant.

Based on the data generated during this study, Didecyldimethylammonium Chloride was found to be photolytically stable in the absence of a photosensitiser. An accurate estimate of the photolysis rate constants and the half-life for solutions containing no photosensitiser and all dark controls (both sensitised and nonsensitised) could not be determined since no significant degradation of the test substance was detected during the 30 day evaluation period. The overall mean 14C-activity accountability for this study was 98.5%.

There was very little volatalisation of the 14C in any of the test systems.

The mass balance for each system (non-photosensitised and photosensitised) was > 97%

Observed pH (mean of two values) for DDAC Photolysis samples
Sample Non-sensitized Non-sensitized Sensitized Sensitized
Day Exposed Dark Exposed Dark
0 7.00 7.00 7.00 7.00
1.03 7.01 7.00 7.00 7.00
2.02 7.02 7.02 7.00 7.00
7.03 7.03 7.05 6.97 7.04
14.0 7.00 7.00 6.84 7.00
21.0 7.05 7.06 6.80 7.05
29.9 7.03 7.05 6.60 7.05

DDAC Photodegradation in Solution – Exposed samples, non-photosensitized system
Sample µg/mL % as Parent as µg/mL Percent of Natural
Day Expressed as Determined DDAC Time Zero Logarithm of
Parent By RTLC Concentration % Time Zero
Equivalents
0 8.58 95.6 8.20 100 4.61
1.03 8.43 94.7 7.98 97.3 4.58
2.02 8.79 93.1 8.18 99.8 4.60
7.03 8.54 93.9 8.02 97.8 4.58
14.0 8.64 97.3 8.41 103 4.63
21.0 7.76 96.4 7.48 91.2 4.51
29.9 8.07 96.6 7.80 95.0 4.55

DDAC Photodegradation in Solution – Dark samples, non-photosensitized system
Sample µg/mL % as Parent as µg/mL Percent of Natural
Day Expressed as Determined DDAC Time Zero Logarithm of
Parent By RTLC Concentration % Time Zero
Equivalents
0 8.58 95.6 8.20 100 4.61
1.03 8.68 93.5 8.12 98.9 4.59
2.02 8.26 92.8 7.67 93.5 4.54
7.03 8.34 94.8 7.91 96.4 4.57
14.0 8.40 95.7 8.04 98.0 4.59
21.0 8.44 95.7 8.08 98.5 4.59
29.9 8.04 97.0 7.80 95.1 4.55

DDAC Photodegradation in Solution – Exposed samples, photosensitized system
Sample µg/mL % as Parent as µg/mL Percent of Natural
Day Expressed as Determined DDAC Time Zero Logarithm of
Parent By RTLC Concentration % Time Zero
Equivalents
0 8.59 96.1 8.25 100 4.61
1.03 8.60 97.6 8.39 102 4.62
2.02 8.56 95.7 8.19 99.2 4.60
7.03 8.71 92.8 8.08 97.9 4.58
14.0 8.63 80.0 6.90 83.6 4.43
21.0 8.62 92.1 7.94 96.2 4.57
29.9 8.47 90.7 7.68 93.1 4.53

DDAC Photodegradation in Solution – Dark samples, photosensitized system
Sample µg/mL % as Parent as µg/mL Percent of Natural
Day Expressed as Determined DDAC Time Zero Logarithm of
Parent By RTLC Concentration % Time Zero
Equivalents
0 8.59 96.1 8.25 100 4.61
1.03 8.51 97.7 8.31 101 4.61
2.02 8.78 95.7 8.40 102 4.62
7.03 8.53 95.7 8.16 98.9 4.59
14.0 8.21 96.7 7.94 96.2 4.57
21.0 8.30 96.3 7.99 96.8 4.57
29.9 8.20 97.5 8.00 96.9 4.57

DDAC Photodegradation Mass Balance Table – Non-sensitized samples
Sample Total Activity Percent of Time Zero
Day as µg/mL DDAC Concentration
Exposed Dark Exposed Dark
0 8.58 8.58 100 100
1.03 8.43 8.68 98.3 101
2.02 8.79 8.26 102 96.3
7.03 8.54 8.34 100 97.2
14.0 8.64 8.40 101 97.9
21.0 7.76 8.44 90.4 98.4
29.9 8.07 8.04 94.1 93.7
Mean 97.9 97.8
Overall mean and ±SD 97.9 ± 3.29

 
DDAC Photodegradation Mass Balance Table – Sensitized samples
Sample Total Activity Percent of Time Zero
Day as µg/mL DDAC Concentration
Exposed Dark Exposed Dark
0 8.59 8.59 100 100
1.03 8.60 8.51 100 99.1
2.02 8.56 8.78 99.7 102
7.03 8.71 8.53 101 99.3
14.0 8.63 8.21 100 95.6
21.0 8.62 8.30 100 96.6
29.9 8.47 8.20 98.6 95.5
Mean 100 98.3
Overall mean and ±SD 99.1 ± 1.93

Results with reference substance:

No data

The test substance was found to be photolytically stable in the absence of a photosensitiser. An accurate estimate of the photolysis rate constants and the half-life for solutions containing no photosensitiser and all dark controls (both sensitised and nonsensitised) could not be determined since no significant degradation of the test substance was detected during the 30 day evaluation period. Essentially all of the14C-moiety not present as parent compound was found in a single degradate.

Validity criteria fulfilled:

yes

Conclusions:

The test substance is photolytically stable in the absence of a photosensitising agent. In the presence of the energy from a xenon arc lamp and the photosensitising agent, acetone, it appears that Didecyldimethylammonium Chloride breaks down to form a single degradate.

Executive summary:

In a study conducted in accordance with U.S.EPA-FIFRA N-161-2, the photolysis rate of Didecyldimethylammonium Chloride was determined. The test substance (at a nominal concentration of 10 µg/ml was conducted at 25°C in aqueous solution buffered at pH 7) was exposed to a xenon arc light source for 30 days and controls were kept in the dark for 30 days. The test substance is photolytically stable in the absence of a photosensitising agent. In the presence of the energy from a xenon arc lamp and the photosensitising agent, acetone, it appears that Didecyldimethylammonium Chloride breaks down to form a single degradate.

Description of key information

The study has been conducted with the chemical and structural analog, Didecyldimethylammonium Chloride (DDAC). The photolysis data available for DDAC are adequate for Didecylmethylpoly(oxyethyl)ammonium Propionate. The study carried out in accordance with the U.S.EPA-FIFRA N-161-2 guidelines. No degradation occurred in the presence of acetone without exposure to the light source. The test substance is photolytically stable in absence of a photosensitising agent.   

Key value for chemical safety assessment

Half-life in water:

227 d

Additional information

In a study conducted in accordance with U.S.EPA-FIFRA N-161-2, the photolysis rate of Didecyldimethylammonium Chloride (read- across) was determined. The test substance (at a nominal concentration of 10 µg/ml was conducted at 25°C in aqueous solution buffered at pH 7) was exposed to a xenon arc light source for 30 days and controls were kept in the dark for 30 days. The test substance is photolytically stable in the absence of a photosensitising agent. In the presence of the energy from a xenon arc lamp and the photosensitising agent, acetone, it appears that Didecyldimethylammonium Chloride breaks down to form a single degradate.

Based on the close similarities of this structural analog, didecylmethylpoly(oxyethyl)ammonium propionate is expected to undergo comparable phototransformation in water.