Tin(2+) neodecanoate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11.2017 to 04.2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2108

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Tin(2+) neodecanoate

EC Number:

256-370-0

EC Name:

Tin(2+) neodecanoate

Cas Number:

49556-16-3

Molecular formula:

C20H38O4Sn

IUPAC Name:

λ²-tin(2+) bis(2,2-dimethyloctanoate)

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The test substance concentrations were measured via DOC measurement at time 0 and 72 h after filtration of the samples.

Test solutions

Vehicle:

no

Details on test solutions:

Due to the very low water solubility of the test item individual Water Accommodated Fractions (WAFs) of the test item will be prepared according to the OECD guidance No. 23.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Raphidocelis subcapitata
- Strain: Catalog No 61.81 SAG
- Source (laboratory, culture collection): The organism was obtained from 'Sammlung von Algenkulturen', Göttingen (SAG), Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, D-37073 Göttingen, Germany
- Age of inoculum (at test initiation): 3 d
- Method of cultivation:
Stock culture: The stock cultures are maintained fulfilling the criteria of the OECD guideline (culture medium recommended by Bringmann und Kühn (1980).
Pre-culture: Prior to testing a pre-culture will be established in standard OECD growth medium to obtain exponentially growing algae for the test. The culture duration of the pre-cultures was 3 days.

ACCLIMATION
- Acclimation period: 3 d
- Culturing media and conditions (same as test or not): OECD growth medium according to OECD 201 was used.
- Any deformed or abnormal cells observed: Normal appearance of algal cells at all concentrations. Some cell debris at 63.3 and 200.0 mg test iten/L (nominal concentration)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21 - 24°C (controlled at ± 2°C)

pH:

at test start: 7.00-7.51
at test end:7.61-7.97

Nominal and measured concentrations:

Control, 2.00, 6.33, 20.0, 63.3 and 200 mg test item/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL conical flasks
- Type (delete if not applicable): covered with air-permeable silicone-sponge caps
- Material, size: glas, 250 mL
- Aeration: not reported
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- Initial cells density: 1.904 x 10E6 cells/mL
- Control end cells density: 10,000 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8 (test medium only)


GROWTH MEDIUM
- Standard medium used: yes according to guideline

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: culture medium prepared according to guideline
- Culture medium different from test medium: medium of the pre-culture and test culture were the same
- Intervals of water quality measurement: the pH of the test solutions was measured at the start and at the end of the exposure; temperature and light intensity were measured daily.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous light
- Light intensity and quality: ranged from 93.94 to 96.96 µE m-2 s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: electronic particle counter

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.16
- Range finding study: performed
- Test concentration (range finding study): 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes
- Due to the very low water solubility of the test item individual Water Accommodated Fractions (WAFs) of the test item will be prepared according to the OECD guidance No. 23.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

63.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

6.33 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

54.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

11.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Results with reference substance (positive control):

- Results with reference substance valid? yes
- The sensitivity of the test organism is routinely checked using 3,5-dichlorophenol as primary standard following internal SOPs in a non-GLP test twice a year. The latest (December 2017) ErC50 value of 2.90 mg/L (nominal; 95% confidence limits: 2.66 – 3.16 mg/L) for inhibition of growth rate is in good agreement with the results of an international ring test with an ErC50 of 3.38 ± 1.30 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a study conducted according to OECD Guideline 201 using Raphidocelis subcapitata as test organism, the EyC50 (0 -72 h) value was 54.9 mg/L and the LOEC and NOEC values were 20.0 and 6.33 mg/L, respectively, after 72 h of exposure. For the parameter growth rate the ErC50 (0 -72 h) value was > 200 mg/L and the LOEC and NOEC values were 63.3 and 20 mg/L, respectively, after 72 h of exposure.

Executive summary:

In an alga growth inhibition test conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test) cultures of Raphidocelis subcapitata were exposed to nominal test substance concentrations of 2.00, 6.33, 20.0, 63.3, and 200 mg/L Neodecanoic acid, tin(2+) salt (2:1) for 72 h under static conditions. The test substance concentrations were checked by DOC analysis at 0 and 72 h after application. For the parameter yield the EyC50 (0 -72 h) value was 54.9 mg/L and the LOEC and NOEC values were 20.0 and 6.33 mg/L, respectively, after 72 h of exposure. For the parameter growth rate the ErC50 (0 -72 h) value was > 200 mg/L and the LOEC and NOEC values were 63.3 and 20 mg/L, respectively, after 72 h of exposure.

The study is regarded as reliable without restriction and satisfies the requirements of the guideline.

Synopsis

Test organism: Raphidocelis subcapitata

Test type: static

Test duration: 72 h

Results:

Yield

EyC50 (0 -72 h): 54.9 mg/L

LOEC (0 -72 h): 20.0 mg/L

NOEC (0 -72 h): 6.33 mg/L

Growth rate

ErC50 (0 -72 h): > 200 mg/L

LOEC (0 -72 h): 63.3 mg/L

NOEC (0 -72 h): 20 mg/L (all values refer to nominal concentrations)

Endpoint(s) affected: growth rate, yield