Butanamine, N,N-dibutyl-, branched and linear, fluorinated

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Mar 1984 - 01 Jun 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: test predated OECD or EC guidelines but is equivalent, nominal concentrations only, limit test.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

not applicable

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Perfluorotributylamines

IUPAC Name:

Perfluorotributylamines

Details on test material:

- Name of test material (as cited in study report): FC-43
- Analytical purity: not reported. Test material purified by silica gel column before test as per normal practice for commercial sale. Test substance reflects the product as marketed at time of the study date.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 1000 mg of FC-43 was added to 2000 mL of DI water. The solution was sonicated one hour and mixed overnight. A stock solution was made up freshly every one to two days for the semi-static assay. pH for the stock solutions ranged from 4.2 - 5.2, average 4.7 (See Table 1). The stock solution was diluted for the assay using well water as diluent.
- Concentrations (nominal): 0 mg/L (blank), 4 mg/L, 40 mg/L, 400 mg/L
- Controls: 100% well water blank.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): not reported

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Remarks on exposure duration:

replacement of test solution every 48 hours

Test conditions

Hardness:

variable

Test temperature:

22-23°C

pH:

control, 4 mg/L and 40 mg/L, 7.9 - 8.2; 400 mg/L, 7.5 - 7.8

Dissolved oxygen:

6.1 -9.1 mg O2/L

Salinity:

not applicable

Nominal and measured concentrations:

0 mg/L (blank), 4 mg/L, 40 mg/L, 400 mg/L (nominal only)

Details on test conditions:

TEST SYSTEM
- Test vessel: jar
- Material, size, headspace, fill volume: 500 mL in a 625 mL jar
- Aeration: none. See Table 1 for DO concentration at renewal.
- Renewal rate of test solution (frequency/flow rate): every 48 hrs. Test chambers were examined to obtain approximate numbers of young, but were not opened and counted until renewal.
- No. of organisms per vessel: five
- No. of vessels per concentration (replicates): four
- No. of vessels per control (replicates): four

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: well water, hardness 244 mg/L as CaCO3
- Test medium hardness by test substance concentration: 0 mg/L and 4 mg/L, 244 mg/L as CaCO3. 40 mg/L, 236 mg/L as CaCO3. 400 mg/L, 104 mg/L as CaCO3. It should be noted that hardness did not dilute proportionally.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: not reported
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality in adults and live young at day 0, 2, 4 then daily from day 6 to study conclusion. Dead young every two days beginning at day 6

VEHICLE CONTROL PERFORMED
Not applicable

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

40 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Effect concentrations 2

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.71 µg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: Concentration is maximum attainable test substance concentration in abiotic samples during the 2012 acute Daphnia toxicity test (elsewhere in this dossier)

Details on results:

The control population met the following criteria:
-Adult mortality: none
-First brood release: 6 days
-Cumulative young per adult: 14-day, 87; 21-day, 186
-Ephippia: none
-Dissolved oxygen: 82% saturation
-pH: 8.0 ± 0.2
This study precedes the publication of guidelines for long-term daphnia testing. However, the control population criteria demonstrate the ability of this laboratory to successfully conduct a study of this type.

Due to the method used for making the test solutions, each test concentration had a different hardness with the highest concentration (400 mg/L) having a substantially different hardness (104 mg/L as CaCO3 for the 400 mg/L test concentration v. ca 240 mg/L as CaCO3 for all other concentrations from negative control to 40 mg/L). The hardness of the highest test concentration is below that recommended for Daphnia magna in the current revision of OECD TG202 (140 mg/L). Moreover, the stock solution, which constituted 80% of the test solution for the highest concentration, was notably acidic (Table 1) and caused a slight but significant decrease in test solution pH relative to controls. The formulation method (1 hour sonication with overnight mixing) may have created some impurities in the test stock solution. In later tests, solutions made in the same way (sonication) as the stock solution in the long-term toxicity study had a TOC concentration of 3 mg/L, whereas a solution prepared only by stirring had a TOC <2 mg/L. A reasonable estimate is that 3 equivalents of strong acid (HF and pefluorobutyric acid) would be produced per equivalent of PTBA. To attain a pH of 4.2, no more than ca. 3 % of starting PTBA would be consumed in the process. The acidity of the stock solution may be explained by this mechanism.

To address whether the reduction in reproduction seen at the 400 mg/L loading rate was due to differing levels of hardness, a later assay was conducted using 100% well water (hardness 248 - 256 as mg CaCO3/L) and 1:4 well water:DI water (hardness 76 - 84 as mg CaCO3/L). Results for 100% well water were 164 ± 19 live young per surviving adult (mean ± standard deviation) v. 146 ± 10 live young per surviving adult for 1:4 well water:DI water. The 11% difference in fecundity was not statistically significant.

The significant difference in reproduction seen at the highest test concentration relative to controls may have been confounded with differences in water quality or impurities in the stock solution and cannot be ascribed to the test substance alone. Further, at the loading rates used in this study, the test substance would have been at saturation levels at both 40 mg/L and 400 mg/L loading rates, indicating that the effect on reproduction seen only at 400 mg/L was due to some factor other than the test substance. Therefore, the highest loading rate does not constitute a valid LOEC.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

The 21-day NOEC of the test substance to Daphnia magna reproduction is 40 mg/L (nominal concentration). Based on contemporary data, the actual dissolved concentration of test substance was 0.710 µg/L.

Executive summary:

Chronic toxicity of the test substance was assessed in a 21-day reproduction study using Daphnia magna. No test guideline was cited, although the test was broadly similar to April 1984 OECD guidelines for long-term reproduction tests of Daphnia magna. Test solutions were refreshed every two days. The test substance is a mixture of isomers. Stock solutions (500 mg/L) were made by sonicating and mixing the test substance with distilled, deionized water, with dilution to the appropriate concentration with well water. The resulting stock solution was notably acidic. Nominal concentrations of 4 mg/L, 40 mg/L and 400 mg/L were tested. 20 total organisms were tested at each exposure level. Live and dead offspring were counted every other day until Day 21. Results for the 400 mg/L loading rate were confounded by differences in water quality parameters (hardness and pH) in those test vessels, and the results are not considered reliable. No effect was observed at 4 and 40 mg/L loading rates. The test was conducted in such a way as to maintain test substance saturation in the test medium throughout the test period. Based on contemporary data, the actual dissolved concentration of PTBA was 0.710 µg/L throughout the exposure period. The 21-day NOEC for reproduction of Daphnia magna was therefore 40 mg/L (nominal concentration), 0.710 µg/L (estimated concentration).

This study predates chronic aquatic invertebrate test guidelines and is not compliant with GLP criteria. However, performance of controls was in keeping with current validity criteria and the laboratory had experience with performing chronic tests. The study uses an inconsistent test matrix with varying water hardness. Hardness at the highest test concentration was below the level recommended for D. magna in the current revision of OECD TG202. The significant difference in reproduction seen at the highest test concentration relative to controls may have been confounded with the differences in water quality and cannot be ascribed to the test substance alone. There is evidence that the method for formulating the stock solution created impurities with an unknown impact on test results. Nevertheless, this study serves to a establish a minimum or worst case value of the NOEC and is conservative for purposes of PNEC calculation. Therefore, this study is classified as reliable with restrictions and is suitable for calculation of PNECs in support of Risk Assessment.