3,4,5,6-tetrachloro-N-[2-(4,5,6,7-tetrachloro-2,3-dihydro-1,3-dioxo-1H-inden-2-yl)-8-quinolyl]phthalimide

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD 318

GLP compliance:

no

At any of the time points mentioned in the TG-318, the influence of Ca is critical. Regardless of pH, the pigment is least stable in 10 mM Ca, representing high water hardness. After 6h, the samples showed high dispersion stability in 0 mM Ca and 1 mM Ca and low stability in 10 mM Ca at all pH. After 24 hours the stability in 0 mM Ca at all pH became intermediate. The sample stability in 1 mM Ca at pH = 4 remained high and for samples at pH = 7 and pH = 9 became intermediate. For the samples in 10 mM Ca the stability remained low.

 

Full results of the dispersion stability in the presence of NOM
	Ca(NO3)2	Stability after 6h	Standard deviation	Stability after 15h	Standard deviation	Stability after 24h	Standard deviation
	[mM]	[%]	[%]	[%]	[%]	[%]	[%]
pH 4	0	95.7	1.1	92.7	0.9	86.9	7.5
pH 4	1	98.7	0.5	95.8	1.1	90.5	1.0
pH 4	10	9.6	0.9	3.9	0.5	2.3	0.3
.
pH 7	0	92.5	0.6	86.7	1.4	80.9	2.7
pH 7	1	97.5	2.2	94.9	3.9	89.1	8.0
pH 7	10	9.2	1.3	3.5	0.8	2.1	0.5
.
pH 9	0	94.5	2.8	89.3	4.6	84.3	5.8
pH 9	1	95.7	3.6	90.5	9.5	75.8	12.3
pH 9	10	9.6	1.1	4.3	0.4	2.5	1.3

 

To rationalize the observed dispersion stability, we finally checked the particle size distribution directly in the environmental medium. We applied the NanoDefine method of Analytical Ultracentrifugation (SOP AUC-RI, published by 3). The centrifugation parameters are given in the methods section.

As required by TG318, paragraph 31, the tested nanomaterial was pre-wetted in ultrapure water and left in the form of wet-paste for 24 h. The TG318 requires this step “to insure the proper interaction of nanomaterial surface with ultrapure water.” We visually observed incomplete wetting, and so any ensuing measurement would have been incorrect. In accord with the NanoGenoTox dispersion protocol, a drop of ethanol was added, successfully transferred the powder into a paste, which was then further diluted as specified in the TG318

The observed size distributions confirm the moderate agglomeration at 1 mM Ca, pH7, with NOM (Figure 4). If the particles would have been significantly dissolved, no size distribution would be observable at all by this method, which relies on the detection of the movement of particles during centrifugal separation.

Additionally, the centrifugation methods include a determination of the remaining absorption after centrifugation, fully consistent with the conventional determination of the dissolved fraction after centrifugation as recommended by the TG-318. The remaining absorption was measured at ca. 0.042. This is a fraction of 3% of the initial absorption, but actually is close to the LOD of the built-in UV/Vis detector. Considering the LOD, between 0% and 3% of the sample may have been dissolved.

All evidence combined, the results after centrifugation confirm that at least 97% of the observed dispersion stability has to be attributed to the particles, not to dissolution.

Conclusions:

At any of the time points mentioned in the TG-318, the influence of Ca is critical. Regardless of pH, the pigment is least stable in 10 mM Ca, representing high water hardness. After 6h, the samples showed high dispersion stability in 0 mM Ca and 1 mM Ca and low stability in 10 mM Ca at all pH. After 24 hours the stability in 0 mM Ca at all pH became intermediate. The sample stability in 1 mM Ca at pH = 4 remained high and for samples at pH = 7 and pH = 9 became intermediate. For the samples in 10 mM Ca the stability remained low.

Cross-reference 2

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

Parameter ranges: In domain; Structural domain: Out of domain (Correct fragments: 71.43%; Incorrect fragments: 0%; Unknown fragments: 28.57%); Unable to mineralize: --

Principles of method if other than guideline:

Estimation of results of OECD screening tests on ready biodegradation in water: CATALOGIC (v5.14.1.5); CATALOGIC 301C v.11.16

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Duration of test (contact time):

28 d

Parameter:

probability of ready biodegradability (QSAR/QSPR)

Remarks on result:

not readily biodegradable based on QSAR/QSPR prediction

Parameter:

half-life in days (QSAR/QSPR)

Remarks on result:

other: primary half-life: 2.71 days; ultimate half-life: 1y 0m 5d

Details on results:

Model domain similarity:
- Parametric domain: 100%
- Structural domain: out of domain (Correct fragments: 71.43%; Incorrect fragments: 0%; Unknown fragments: 28.57%);
- Mechanistic domain: 0%

Predicted BOD value: 0.05 ± 0.0121

Prediction: Not ready degradable

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance is not readily biodegradable (according to OECD criteria)

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

3,4,5,6-tetrachloro-N-[2-(4,5,6,7-tetrachloro-2,3-dihydro-1,3-dioxo-1H-inden-2-yl)-8-quinolyl]phthalimide

EC Number:

250-063-5

EC Name:

3,4,5,6-tetrachloro-N-[2-(4,5,6,7-tetrachloro-2,3-dihydro-1,3-dioxo-1H-inden-2-yl)-8-quinolyl]phthalimide

Cas Number:

30125-47-4

Molecular formula:

C26H6Cl8N2O4

IUPAC Name:

4,5,6,7-tetrachloro-2-[2-(4,5,6,7-tetrachloro-1,3-dioxo-2,3-dihydro-1H-inden-2-yl)quinolin-8-yl]-1H-isoindole-1,3(2H)-dione

Test material form:

solid: nanoform

Details on test material:

- Physical state/ appearance: solid / yellow
- Shape of particles: spherical
- Aspect ratio: 1.5
- Particle size distribution: 62.7 nm
- Crystal structure: crystalline
- Surface area of particles: 29.6 m^2/g
- Surface treatment: no

Results and discussion

Transformation products:

not specified