Tall oil, reaction products with diethylenetriamine

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

It is considered appropriate to address the data requirements for DTO_DETA by read-across to the available studies on the main components of DTO_DETA: AAI_DETA and Rosin.
DTO_DETA and AAI_DETA are each a mixture of constituents which include monoamide, diamide, residual amine and imidazoline (mono-, di- and tri-condensate) chemical structures. The substances therefore have common functional groups based on amide, amine and imidazoline moieties and are sufficiently similar in terms of chemical structure to support a read-across approach.
DTO_DETA contains comparatively lower levels of imidazolines and higher levels of resin acids than AAI_DETA and therefore consideration of data for resin acids is also considered necessary. The main resin acid in DTO_DETA is abietic acid, but abietic acid derivatives and other acids, such as pimaric acid, are also found in notable quantities, and the resin acids collectively are known as ‘rosin’. DTO_DETA contains upto 25% unreacted rosin, and taking into account the compositional information available for the rosin in DTO_DETA and Rosin (CAS# 8050-09-07, EC# 232-475-7), the latter was considered appropriate for read-across to DTO_DETA.
The AAI_DETA dataset is worst case with regards to biodegradability and aquatic toxicity, with the dataset for Rosin showing a lower toxicity profile. Therefore, AAI_DETA is considered to be a worst case read-across source for the DTO_DETA target substance in the context of toxicity to aquatic algae and cyanobacteria.

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.343 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

94.4% a.i.

Basis for effect:

growth rate

Remarks on result:

other: 0.325-0.371

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.505 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

94.4% a.i.

Basis for effect:

growth rate

Remarks on result:

other: 0.461-0.568

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):
- Unusual cell shape: No
- Colour differences: No
- Flocculation: No
- Adherence to test vessels: No
- Aggregation of algal cells: No
- Other: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal
values: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50:
Rate-related inhibition: 0.82 (CI 0.78 - 0.85) mg/L
Yield Inhibition: 0.37 (CI 0.36 - 0.40) mg/L

Reported statistics and error estimates:

EC10-, EC20- and EC50-values of the growth rate and yield inhibition after 72 h were calculated by sigmoidal dose-response regression. Calculation of the confidence intervals of EC10-, EC20- and EC50- values were carried out from the best fit values, the standard error and the t-distribution with the software GraphPad Prism.

EC₁₀-, EC₂₀-and EC₅₀- values and 95 % Confidence Intervals of Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7) (0-72 h) based on nominal test item concentrations [mg/L]

	Rate-related inhibition
ErC10	0.343 (0.325 – 0.371)
ErC20	0.395 (0.372 – 0.436)
ErC50	0.505 (0.461 – 0.568)
	Inhibition of yield
EyC10	0.265 (0.249 – 0.277)
EyC20	0.295 (0.286 – 0.305)
EyC50	0.356 (0.347 – 0.367)

 

Cell densities

Nominal test item concentration [mg/L]	Replicate No.	Cell density [cells/mL]
		0 h	24 h	48 h	72 h
10.0	1	9787	-426	-1047	0
	2	9787	-1220	-2222	0
	3	9787	-233	-2264	0
	Mean	9787	-626	-1844	0
3.20	1	9787	-2052	-2137	1520
	2	9787	-1742	-1977	380
	3	9787	-1690	-1789	760
	Mean	9787	-1828	-1968	887
1.00	1	9787	-562	1031	5722
	2	9787	975	1745	5327
	3	9787	1623	2958	13622
	Mean	9787	679	1911	8224
0.320	1	9787	37860	278636	1622761
	2	9787	39750	304557	1657894
	3	9787	32695	198158	1317148
	Mean	9787	36768	260450	1532601
0.100	1	9787	48125	569717	2285269
	2	9787	61459	628674	2188829
	3	9787	57248	553027	2240600
	Mean	9787	55611	583806	2238233
Control	1	9787	54164	640687	2232516
	2	9787	58145	665385	2138901
	3	9787	63141	667914	2230335
	4	9787	56905	633096	2290857
	5	9787	56914	642755	2150971
	6	9787	63677	653038	2288211
	Mean	9787	58824	650479	2221965

 

Evaluation after 72 h

Nominal test item concentration [mg/L]	Replicate No.	Growth rate [d^-1]	Rate-related inhibition [%]	Yield [cells/mL]	Inhibition of yield [%]
10.0	1	0.000	100	-9787	100
	2	0.000	100	-9787	100
	3	0.000	100	-9787	100
	Mean	0.000	100	-9787	100
3.20	1	-0.621	100	-8267	100
	2	-1.083	100	-9407	100
	3	-0.852	100	-9027	100
	Mean	-0.852	100	-8900	100
1.00	1	-0.179	100	-4065	100
	2	-0.203	100	-4460	100
	3	0.110	93.9	3835	99.8
	Mean	-0.090	98.0	-1563	99.9
0.320	1	1.70	5.79	1612974	27.1
	2	1.71	5.39	1648107	25.5
	3	1.63	9.63	1307361	40.9
	Mean	1.68	6.94	1522814	31.2
0.100	1	1.82	-0.52	2275482	-2.86
	2	1.80	0.27	2179042	1.50
	3	1.81	-0.16	2230813	-0.840
	Mean	1.81	-0.14	2228446	-0.730
Control	1	1.81	-	2222729	-
	2	1.80	-	2129114	-
	3	1.81	-	2220548	-
	4	1.82	-	2281070	-
	5	1.80	-	2141184	-
	6	1.82	-	2278424	-
	Mean	1.81	-	2212178	-

 

 

Section-by-Section and Average Specific Growth Rates of the Control Group (0-72 h)

	Replicate No.	Specific growth rate [d^-1] section-by-section			Mean (0-72 h)	SD ±	VC %	Mean VC %
		0.-24 h	24-48 h	48-72 h
Control	1	1.71	2.47	1.25	1.81	0.617	34.1	32.7
	2	1.78	2.44	1.17	1.80	0.635	35.4
	3	1.86	2.36	1.21	1.81	0.579	32.0
	4	1.76	2.41	1.29	1.82	0.564	31.0
	5	1.76	2.42	1.21	1.80	0.609	33.9
	6	1.87	2.33	1.25	1.82	0.539	29.6
				Mean	1.81
				SD ±	0.01
				VC %	0.54

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the target substance DTO_DETA to aquatic algae is estimated to be a 72 h EC10 = 323.8 µg a.i./L and EC50 = 476.7 µg a.i./L, based on read-across from a study testing AAI_DETA.

Executive summary:

The toxicity of the target substance DTO_DETA to aquatic algae is estimated to be a 72 h EC₁₀ = 323.8 µg a.i./L and EC₅₀ = 476.7 µg a.i./L, based on read-across from a study testing AAI_DETA.

As explained in the justification for type of information, DTO_DETA and AAI_DETA are each a mixture of constituents which include monoamide, diamide, residual amine and imidazoline (mono-, di- and tri-condensate) chemical structures. The substances therefore have common functional groups based on amide, amine and imidazoline moieties and are sufficiently similar in terms of chemical structure to support a read-across approach.

DTO_DETA contains comparatively lower levels of imidazolines and higher levels of resin acids than AAI_DETA and therefore consideration of data for resin acids is also considered necessary. The main resin acid in DTO_DETA is abietic acid, but abietic acid derivatives and other acids, such as pimaric acid, are also found in notable quantities, and the resin acids collectively are known as ‘rosin’. DTO_DETA contains upto 25% unreacted rosin, and taking into account the compositional information available for the rosin in DTO_DETA and Rosin (CAS# 8050-09-07, EC# 232-475-7), the latter was considered appropriate for read-across to DTO_DETA and relevant studies testing Rosin are included as separate supporting source records.

The AAI_DETA dataset is worst case with regards to biodegradability and aquatic toxicity, with the dataset for Rosin showing a lower toxicity profile. Therefore, AAI_DETA is considered to be a worst case read-across source for the DTO_DETA target substance in the context of toxicity to aquatic algae and cyanobacteria.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-02-16 to 2010-03-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP, All validity criteria fulfilled, complete identification of test substance, including chemical analyses

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7)
- Physical state: Liquid, amber, viscous
- Analytical purity: 94 %
- Purity test date: 2009-05-11
- Lot/batch No.: S000922
- Expiration date of the lot/batch: 2017-07-02
- Water solubility: Insoluble
- Density: 980 kg/m3 at 20 °C
- pH: 10 - 12 at 75 % solution
- Stability under test conditions: Not specified
- Storage condition of test material: Room temperature, protected from moisture and light, under nitrogen

Analytical monitoring:

yes

Details on sampling:

- Concentrations: From the series of concentrations the second lowest and the second highest test concentration (0.320 and 3.20 mg/L) and the control were analytically verified at the beginning of the test.
- Sampling method: Separate replicates for the test item analysis after 0 and 72 h were prepared without algae. Analysis after 72 h of these concentrations were carried out. Sorption to the walls of the glass container was checked out of one test replicate (prepared with algae) of a concentration level close to the EC50-value (the second lowest test concentration of 0.320 mg/L was analysed).
- Sample storage conditions before analysis: The samples were stored under room temperature until start of analysis, if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of 10 mg/L was freshly prepared. Dispersion treatment was ultrasound for 5 min at room temperature. An equilibration phase for 1 h before application was carried out.
- Eluate: Natural water
- Differential loading: 0.100 - 0.320 - 1.00 - 3.20 - 10.0 mg/L
- Controls: Six replicates without test item were tested under the same test conditions as the test replicates.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata HINDAK
- Strain: SAG 61.81
- Source (laboratory, culture collection): SAG Pflanzenphysiologisches Institut der Universitaet Goettingen, Nikolausberger Weg 18, D-37073 Goettingen, Germany
- Age of inoculum (at test initiation): 4 days
- Method of cultivation: Fresh stocks were prepared from Z-Agar. Light intensity amounted 35 - 70 µE x m-2 x s-1 for 24 h per day.


ACCLIMATION
- Culturing media and conditions (same as test or not): Not the same, standard growth medium
- Any deformed or abnormal cells observed: No

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

After 72 h of exposure, 0.2 – 1 mL aliquots of the test medium (i.e. samples of exposed algal cells) from test concentrations 1.00 – 3.20 mg/L and control were transferred to 10 mL untreated test medium. Algae were then allowed to grow for further 3 – 10 days under test conditions. The test item effect was observed to be reversible at these concentrations. Therefore, there is potential for recovery following exposure up to 3.20 mg/L (second highest test concentration).
For results please refer to "Any other information on materials and methods".

Hardness:

Not measured

Test temperature:

Mean: 22.5 °C, Min: 22 °C, Max: 23 °C

pH:

Nominal test item concentration pH-value
[mg/L] Start; 0 h End; 72 h
10.0 8.23 7.87
3.20 8.10 7.81
1.00 8.08 7.71
0.320 8.07 8.19
0.100 8.06 8.56
Control 8.07 8.64

Dissolved oxygen:

Not measured

Salinity:

Not measured, freshwater

Nominal and measured concentrations:

please refer to information on materials and methods

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): sealed with cotton wool plugs
- Material, size, headspace, fill volume: sterile 250 mL Erlenmeyer flasks, test volume 100 mL
- Aeration: Test containers were placed on a rotary shaker and oscillated at appr. 70 rpm
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): One application at test start
- Initial cells density: 9787 cells/mL
- Control end cells density: Mean 2221965 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): None


GROWTH MEDIUM
- Standard medium used: Yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Water of the river Leine was used. This river is located near D-31171 Nordstemmen, Marienbergstraße, Germany (52° 10’ 14.98‘’, 9° 46’ 7.64’’). Water parameters are given in Table 1. Additionally 50 % of the components concentrations of the dilution water (total application volume 6.5 mL/L) acc. to the guideline were added to enable a sufficient growth of algae
River Leine
Location D-31171 Nordstemmen, Marienbergstrasse
Sampling Date 2009-12-15
Weather on Day of Sampling cloudy, ca. - 1 °C
Colour Yellowish, clear
pH 7.97
Conductivity [µS/cm] 386
DOC [mg C/L] 3.9
TOC [mg C/L] 3.9
Ammonium-N [mg N/L] 0.042
Nitrate-N [mg N/L] 2.62
o-Phosphate-P [mg P/L] 0.062
Total Phosphate [mg P/L] 0.053
Suspended Matter [mg/L] 16.2
Total Hardness [mg CO3/L] 154

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: 24 h
- Light intensity and quality: 60 - 120 µE x m-2 x s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] Fluorimeter, via Chlorophyll-a fluorescence (excitation at 436 nm, emission at 685 nm), cell concentrations were related to all cell density values acc. to a calibration curve.



TEST CONCENTRATIONS
- Range finding study: Yes
Results of the Range Finding Test (0 – 72 h)
Results of the Range Finding Test (0 – 72 h)

Nominal
Test Item Concentration
[mg/L] Specific Growth Rate Inhibition[%] Yield Inhibition [%]
10.0 100 100
1.00 28 76
0.10 - 1 - 5
0.01 - 1 - 6
0.001 1 3

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.343 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

94.4% a.i.

Basis for effect:

growth rate

Remarks on result:

other: (0.325 - 0.371)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.505 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

94.4% a.i.

Basis for effect:

growth rate

Remarks on result:

other: (0.461-0.568)

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):
- Unusual cell shape: No
- Colour differences: No
- Flocculation: No
- Adherence to test vessels: No
- Aggregation of algal cells: No
- Other: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50:
Rate-related inhibition: 0.82 (CI 0.78 - 0.85) mg/L
Yield Inhibition: 0.37 (CI 0.36 - 0.40) mg/L

Reported statistics and error estimates:

EC10-, EC20- and EC50-values of the growth rate and yield inhibition after 72 h were calculated by sigmoidal dose-response regression. Calculation of the confidence intervals of EC10-, EC20- and EC50-values were carried out from the best fit values, the standard error and the t-distribution with the software GraphPad Prism.

EC₁₀-_, EC₂₀-and EC₅₀- values and 95 % Confidence Intervals of
Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7) (0-72 h)

                                based on nominal test item concentrations [mg/L]

                               

	Rate-related inhibition
ErC10	0.343 (0.325 – 0.371)
ErC20	0.395 (0.372 – 0.436)
ErC50	0.505 (0.461 – 0.568)
	Inhibition of yield
EyC10	0.265 (0.249 – 0.277)
EyC20	0.295 (0.286 – 0.305)
EyC50	0.356 (0.347 – 0.367)

Cell Densities

	Nominal test item concentration		Replicate		Cell density [cells/mL]
[mg/L]		No.		0 h		24 h	48 h	72 h
10.0		1		9787		-426	-1047	0
		2		9787		-1220	-2222	0
		3		9787		-233	-2264	0
		Mean		9787		-626	-1844	0
3.20		1		9787		-2052	-2137	1520
		2		9787		-1742	-1977	380
		3		9787		-1690	-1789	760
		Mean		9787		-1828	-1968	887
1.00		1		9787		-562	1031	5722
		2		9787		975	1745	5327
		3		9787		1623	2958	13622
		Mean		9787		679	1911	8224
0.320		1		9787		37860	278636	1622761
		2		9787		39750	304557	1657894
		3		9787		32695	198158	1317148
		Mean		9787		36768	260450	1532601
0.100		1		9787		48125	569717	2285269
		2		9787		61459	628674	2188829
		3		9787		57248	553027	2240600
		Mean		9787		55611	583806	2238233
Control		1		9787		54164	640687	2232516
		2		9787		58145	665385	2138901
		3		9787		63141	667914	2230335
		4		9787		56905	633096	2290857
		5		9787		56914	642755	2150971
		6		9787		63677	653038	2288211
		Mean		9787		58824	650479	2221965

Evaluation after 72 h

             

Nominal test item concentration	Replicate	Growth rate		Rate-related inhibition	Yield		Inhibition of yield
[mg/L]	No.	[d^-1]		[%]	[cells/mL]		[%]
10.0	1		0.000	100		-9787	100
	2		0.000	100		-9787	100
	3		0.000	100		-9787	100
	Mean		0.000	100		-9787	100
3.20	1		-0.621	100		-8267	100
	2		-1.083	100		-9407	100
	3		-0.852	100		-9027	100
	Mean		-0.852	100		-8900	100
1.00	1		-0.179	100		-4065	100
	2		-0.203	100		-4460	100
	3		0.110	93.9		3835	99.8
	Mean		-0.090	98.0		-1563	99.9
0.320	1		1.70	5.79		1612974	27.1
	2		1.71	5.39		1648107	25.5
	3		1.63	9.63		1307361	40.9
	Mean		1.68	6.94		1522814	31.2
0.100	1		1.82	-0.52		2275482	-2.86
	2		1.80	0.27		2179042	1.50
	3		1.81	-0.16		2230813	-0.840
	Mean		1.81	-0.14		2228446	-0.730
Control	1		1.81			2222729
	2		1.80			2129114
	3		1.81			2220548
	4		1.82			2281070
	5		1.80			2141184
	6		1.82			2278424
	Mean		1.81			2212178

Section-by-Section and Average Specific Growth Rates of the Control Group
               (0 – 72 h)

	Replicate No.	Specific growth rate [d^-1]			Mean (0 - 72 h)	SD ±	VC %	Mean VC %
		section-by-section
		0 - 24 h	24 - 48 h	48 - 72 h
Control	1	1.71	2.47	1.25	1.81	0.617	34.1	32.7
	2	1.78	2.44	1.17	1.80	0.635	35.4
	3	1.86	2.36	1.21	1.81	0.579	32.0
	4	1.76	2.41	1.29	1.82	0.564	31.0
	5	1.76	2.42	1.21	1.80	0.609	33.9
	6	1.87	2.33	1.25	1.82	0.539	29.6
				Mean	1.81
				SD ±	0.01
				VC %	0.54

Validity criteria fulfilled:

yes

Conclusions:

Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7) was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 h with the following effect values (nominal concentrations): The EC10-values with 95 % confidence intervals for inhibition of specific growth rate (ErC10) and yield (EyC10) after 72 h were 0.343 (0.325 – 0.371) and 0.265 (0.249 – 0.277) mg/L, respectively. The EC50-values with 95 % confidence intervals for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 h were 0.505 (0.461 – 0.568) and 0.356 (0.347 – 0.367) mg/L, respectively.

The concentrations of Tall oil diethylenetriamine imidazoline were analysed at the concentration levels 0.320 and 3.20 mg/L (prepared without algae) and the control at test start via LC-MS/MS analysis. The measured concentrations at test start were in the range of 79 – 89 % of the nominal values. At the end of the test Tall oil diethylenetriamine imidazoline was analysed at concentration levels 0.320 and 3.20 mg/L (prepared without algae) and gave recoveries of < LOQ - 22 % of the nominal values. Biodegradation as possible reason for this decrease is very unlikely considering the short time frame, also the river water was frozen before use to minimize the microbial activity. The decrease is attributed to additional sorption to suspended matter and DOC due to thermodynamically driven redistribution of the sorbed fraction. No test item could be recovered from the glassware (lower than 5 µg/L, which was the lowest analytical standard). This means that less than 1.6 % of the nominal concentration was observed sorbed to glassware. Therefore all effect values are given based on nominal concentrations of the test item.

The test item effect was observed to be reversible at 1.00 – 3.20 mg/L. Therefore, there is potential for recovery following exposure up to 3.20 mg/L (second highest test concentration).

Executive summary:

The toxicity of Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7) (Batch no.: S000922)to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 at Dr.U.Noack-Laboratorienin 31157 Sarstedt, Germany from February 16 to March 01, 2010 with the definitive exposure phase from February 16 to 19, 2010. The aim of the study was the determination of EC₁₀- , EC₂₀ - and EC₅₀ - values of growth rate and yield over a period of 72 h.

Tall oil diethylenetriamine imidazoline (CAS no. 68442-97-7) is insoluble in water and has a strong tendency to adsorb to negatively charged surfaces such as suspended matter, algae and test vessels or organic material (including dissolved organic matter such as humic acids). Many cationic substances in general but long chain amido amines/imidazolines in particular rank among the most difficult substances to test in environmental toxicology. Standard guideline studies are inappropriate to test substances with such properties and the current REACH Guidance Documents do not provide sufficient guidance concerning bioavaibility and exposure assessment for cationic surface-active substances like the amido amines/imidazolines as these were written with normal hydrophobic chemicals in mind, failing to take into account the lack of bioavaibility that occurs in the environment with cationic surface-active substances.

The aquatic ecotoxicity tests with amido amines/imidazolines were therefore performed in river water to allow a PEC_aquatic,bulk/PNEC_aquatic,bulkapproach and is considered to be conservative but more environmentally realistic than the standard method. This approach is based on PEC estimations representing 'total aquatic concentrations'. To characterize the risk to the aquatic compartment the PEC_aquatic,bulkis compared with the PNEC_aquatic,bulk derived from river water ecotoxicity studies (ECETOC, 2003).

         

In order to class standard laboratory toxicity study valid, it is of particular importance that – besides information on test substance, test method / conditions and test organism used – suitable precautions are taken to prevent the loss of test substance by adsorption and that exposure concentrations are based upon measured levels.

         

For ecotoxicity tests performed using the bulk approach, however, adsorption to suspended matter and DOC is acceptable and only adsorption to glassware should be accounted for. For a valid bulk approach test the concentration-effect relationship should be based on the sum of adsorbed and dissolved substance in the volume of the medium tested. One of the advantages of the bulk approach tests with these difficult substances is that in the presence of suspended matter, humic acids and/or algae, the residual sorption to glassware will be negligible. The results of these bulk approach tests are therefore much easier and more realistic, and if compared to PEC_bulk clearly provide a more appropriate assessment of risks for the environment.

An individual test design was applied. Natural river water was used as dilution medium

The study was conducted under static conditions with an initial cell density of approximately 1 x     10⁴ cells/mL. Five concentrations were tested in a geometrical series with a dilution factor of √10, nominal: 0.100 - 0.320 - 1.00 - 3.20 - 10.0 mg/L. Three replicates were tested for the test item concentrations and six replicates for the control. Environmental conditions were determined to be within the acceptable limits.

The concentrations of Tall oil diethylenetriamineimidazolinewere analysed at the concentration levels 0.320 and 3.20 mg/L (prepared without algae) and the control at test start via LC-MS/MS analysis. The measured concentrations at test start were in the range of 79 – 89 % of the nominal values. At the end of the test Tall oil diethylenetriamineimidazolinewas analysed at concentration levels 0.320 and 3.20 mg/L (prepared without algae) and gave recoveries of  LOQ - 22 % of the nominal values. Biodegradation as possible reason for this decrease is very unlikely considering the short time frame, also the river water was frozen before use to minimize the microbial activity. The decrease is attributed to additional sorption to suspended matter and DOC due to thermodynamically driven redistribution of the sorbed fraction. No test item could be recovered from the glassware (lower than 5 µg/L, which was the lowest analytical standard). This means that less than 1.6 % of the nominal concentration was observed sorbed to glassware. Therefore all effect values are given based on nominal concentrations of the test item.

Tall oil diethylenetriamine imidazoline (CAS No. 68442-97-7) was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 h with the following effect values (nominal concentrations): The EC₁₀-values with 95 % confidence intervals for inhibition of specific growth rate (E_rC₁₀) and yield (E_yC₁₀) after 72 h were 0.343 (0.325 – 0.371) and 0.265 (0.249 – 0.277) mg/L, respectively. The EC₅₀-values with 95 % confidence intervals for inhibition of specific growth rate (E_rC₅₀) and yield (E_yC₅₀) after 72 h were 0.505 (0.461 – 0.568) and 0.356 (0.347 – 0.367) mg/L, respectively.

After 72 h algae were transferred from the nominal concentrations of 1.00 – 3.20 mg/L and the control to fresh untreated medium and allowed to grow for further 3 – 10 d under test conditions. The test item effect was observed to be reversible at these concentrations. Therefore, there is potential for recovery following exposure up to 3.20 mg/L (second highest test concentration).

Description of key information

It is considered appropriate to address the data requirements for DTO_DETA by read-across to the available studies on the main components of DTO_DETA: AAI_DETA and Rosin.
    
    
    
    
    

The toxicity of AAI_DETA to aquatic algae in a valid algal study resulted in a 72 hour EC10 and EC50 based on growth of resp. 323.8 and 476.7 µg a.i./L. For Rosins, the worst case conservative result is an EL50 of >100 mg/L.










  
  
  
  
  

The AAI_DETA dataset is worst case with regards to biodegradability and aquatic toxicity, with the dataset for Rosin showing a lower toxicity profile. Therefore, AAI_DETA is considered to be a worst case read-across source for the M102K target substance in the context of toxicity to aquatic algae and cyanobacteria. The toxicity of M102K to aquatic algae is therefore estimated to be a 72 hour EC10 and EC50 based on growth of resp. 323.8 and 476.7 µg a.i./L, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

476.7 µg/L

EC10 or NOEC for freshwater algae:

323.8 µg/L