Fatty acids, tall-oil, reaction products with linseed oil, maleic anhydride and methanol

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Acute toxicity test conducted on a read-across substance in accordance with an OECD guideline, and GLP compliant (with two reported exceptions); the exceptions to GLP principles did not adversely affect the study integrity or the interpretation of results generated from the study. Analytical monitoring was not conducted due to the complex/unknown composition and the lack of an analytical reference standard. The study incorporated water-soluble fraction with respect to the limited solubility of the test substance. Read-across from another substance in the category.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

The specific conductivity and total alkalinity of the dilution water were not measured at the start of the test. The total hardness of the prepared dilution water (i.e., hardness-adjusted blended freshwater) was measured prior to the start of the WSF.

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The dilution water for the definitive test was a moderately hard freshwater prepared by blending naturally hard well water with well water that was demineralized by reverse osmosis (RO). The well water and RO water were blended together to yield a total hardness of 130 to 160 mg CaCO3/L. The final hardness of the dilution water was adjusted to 134 mg CaCO3/L with an additional aliquot of RO water. Prior to hardness adjustment, dilution water for the definitive test was passed through a sediment filter (5 µm). Characterization of the base water, i.e. ABC well water, used to prepare the dilution water was included in Appendix A of the study report.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Rainbow trout (Oncorhynchus mykiss) were obtained from Trout Lodge, Sumner, Washington. Fish were fed salmon starter daily. No diseases were observed or treated during the 14-day period prior to use in the test. Food was withheld during acclimation for approximately 24 hours prior to initiation of the test, and mortality did not exceed 5 percent during the 48 hours immediately before definitive test initiation. A representative sample of ten acclimated fish were measured at test initiation and ranged from 44 to 54 mm total length (mean and standard deviation 51 ± 3.0 mm). The fish weighed from 0.787 to 1.499 g in blotted wet weight (mean and standard deviation = 1.275 ± 0.210 g). Based on this representative sample, the instantaneous biomass loading rate was 0.595 g of fish tissue per liter of test solution, which is below the protocol maximum loading rate of 1.0 g fish tissue/L.

Test type:

other: static-renewal, at 24 hour intervals

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

134 mg CaCO3/L (prior to WSF preparation)

Test temperature:

14.7 to 16.7°

pH:

7.7 to 8.4

Dissolved oxygen:

Dissolved Oxygen (new): 8.6 to 9.8 mg/L (91 to 103% sat.)
Dissolved Oxygen (old): 6.7 to 8.1 mg/L (70 to 84% sat.)

Nominal and measured concentrations:

0 (control), 3.3, 6.5, 13, 25, 50, and 100 mg TPSA/L

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mortality (fish)

Details on results:

After 96 hours of exposure, mortality was 0% in the control and all test substance treatments and no sublethal effects were observed. Based on nominal loading rates, the 24-hour, 48-hour, 72-hour, and 96-hour LC50 values were >100 mg TPSA/L, the highest concentration tested. The 96 hour NOEC was 100 mg TPSA/L based on nominal loading rates and a lack of mortality and sublethal effects at this and all test substance concentrations.

Reported statistics and error estimates:

Due to lack of mortality in the control and all test substance treatments, no statistical analyses were necessary.

Sublethal observations / clinical signs:

Table 1.          Mortality of Rainbow Trout,Oncorhynchus mykiss,Exposed to the Water Soluble Fraction of Tetrapropenyl Succinic Anhydride for 96 Hours Under Static-Renewal Test Conditions

 

Nominal Loading Rate (mg TPSA/L)	R E P	Cumulative Mortality (% Mortality)^a
		24 Hours	48 Hours	72 Hours	96 Hours
0 (Control)	A	0 (0)	0 (0)	0 (0)	0 (0)
3.3	A	0 (0)	0 (0)	0 (0)	0 (0)
6.5	A	0 (0)	0 (0)	0 (0)	0 (0)
13	A	0 (0)	0 (0)	0 (0)	0 (0)
25	A	0 (0)	0 (0)	0 (0)	0 (0)
50	A	0 (0)	0 (0)	0 (0)	0 (0)
100	A	0 (0)	0 (0)	0 (0)	0 (0)

^aNo sublethal effects were observed.

Note:  Seven fish were placed in each test chamber at initiation. 

Validity criteria fulfilled:

yes

Remarks:

There was no mortality in the control treatment during the course of the study. Therefore, control animals satisfied test acceptability criteria for survival (i.e., ≥ 90%) as stated in the study protocol and the OECD 203 testing guideline.

Conclusions:

Based on nominal loading rates, the 24-, 48-, 72-, and 96 hour LC50 values were >100 mg TPSA/L, the highest concentration tested. No sublethal effects were observed during the exposure. The 96 hour NOEC was 100 mg TPSA/L, based on nominal loading rates and a lack of mortality and sublethal effects at this and all lower test substance concentrations. Data can be read-across among the two analogue substances, based on similar functional groups and similar types of effects. This is adequate to fulfill the information requirements, to be the basis for classification and labelling decisions, and for risk assessment.

Description of key information

The key study was a static-renewal acute fish toxicity test on the effects of the read-across substance tetrapropenyl succinic anhydride (TPSA) on the freshwater rainbow trout Onchorhyncus mykiss, following OECD Guideline 203. No toxicity of TPSA to the fish was observed; the 96-h NOEC was reported as ≥ 100 mg/L (based on the nominal concentration of the water-accommodated fraction); the 96-h EC₅₀ was reported as > 100 mg/L (based on the nominal concentration of the water-accommodated fraction).

The analogue approach will be used for the hazard assessment of an eco-toxicological endpoint (i.e., acute aquatic toxicity to fish). Information from acute fish toxicity testing of the substance tetrapropenyl succinic anhydride (TPSA, CARN 26544-38-7) will be used as the basis for the assessment of ZWA 5496/100. 

The hypothesis is that data can be read-across between the substance and its analogue, because their properties and behaviours are similar, based on similar functional groups and similar types of effects. These features are in accordance with Annex XI, Section 1.5, of Regulation EC No. 1907/2006, using the guidance found in the Read-Across Assessment Framework (ECHA, 2017). 

This read-across uses Scenario 2 from the Read-Across Assessment Framework (different compounds have the same kind of effect).  The two substances each contain one or more hydrophobic carbon chains consisting of unsaturated fatty acids, reacted with maleic anhydride, resulting in a succinic anhydride attached group. These common structural elements result in similar properties such as low water solubility, high octanol-water partition coefficient, and surface activity attributable to the presence of hydrophilic groups to one end of the fatty acid chain. Therefore, these common structural components and similar chemical properties are expected to result in similar behaviour in the acute aquatic fish toxicity assay. 

Read-across between the two analogue substances is substantiated by the similar functional groups and toxicological effects, as provided in the Analogue Approach Assessment Format (AARF) attached to the IUCLID file. It is adequate to fulfill the information requirements of Annex VIII, to be the basis for classification and labelling decisions, and for risk assessment.