Tetrabutyltin

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 April 1993 and 8 April 1993 (experimental phase)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Measured concentrations in the media were not stable; therefore, results were based on geometric mean values.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

No information available

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: test substance was dissolved in 1 % Tween 80/acetone for an initial stock solution of 100 mg/mL. Serial dilutions of this stock solution were prepared with the auxiliary solvent and aliquots added to test water to give the desired series of exposure levels.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: (Straus)
- Source: Institute National de Recherche Chimique Appliquee (IRChA), France
- Age at study initiation (mean and range, SD): young daphnids produced overnight
- Feeding: Cultures were fed daily with a suspension of mixed algae (predominately Scenedesmus and Selenastrum spp.).
- Reproduction: parthoenogenesis

Gravid adults were isolated 24 hours pior to initiation of test

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

146 ± 12 mg CaCO3/L

Test temperature:

21 ºC

pH:

8.0-8.2

Dissolved oxygen:

8.3 - 8.4 mg O2/L

Nominal and measured concentrations:

1, 1.8, 3.2, 5.6 and 10 mg/L (nominal)

Details on test conditions:

- Aeration: 12 hours prior to use by recirulating through a gravel filter bed

- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 20 mL test solution per organism

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: laboratory water filter, dechlorinated and softened through an Elga water purificaiton system. Chlorine and organic contaminats are removed with high grade activated carbon filter. Water passes through a water softener before reverse osmosis tratement.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light, 8 hour dark without supplementary aeration or feeding during 48 hour expsoure period.

Reference substance (positive control):

not specified

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

2.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 2.1 - 3.2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 1.2 - 1.4

Duration:

24 h

Dose descriptor:

other: NOEL

Effect conc.:

0.56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

other: NOEL

Effect conc.:

0.56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Reported statistics and error estimates:

EC50 values and 95 % confidence limits were calculated according to the method of Thompson and Weil (1952, Biometrics 8:51-54). The no effect level is the highest concentration at and below which the incidence of immobilization is equal to or less than 10 %.

Table 1: Immobilization Data after 24 Hours

Cumulative immobilized 24 hours (initial population 10 per replicate)
Nominal Conc (mg/L)	R1	R2	Total
Control	0	0	0
Solvent Control	0	0	0
1.0	0	3	3
1.8	3	0	3
3.2	5	7	12
5.6	10	10	20
10	10	10	20

Table 2: Immobilization Data after 48 Hours

Cumulative immobilized 48 hours (initial population 10 per replicate)
Nominal Conc (mg/L)	R1	R2	Total
Control	0	0	0
Solvent Control	0	0	0
1.0	0	3	3
1.8	10	10	20
3.2	10	10	20
5.6	10	10	20
10	10	10	20

Validity criteria fulfilled:

not specified

Conclusions:

The 48 h EC50 (immobilization) value with Daphnia magna was 1.3 mg/L.

Executive summary:

A study was performed to assess the acute toxicity of Tetrabutyltin (ZK 24.942) to Daphnia magna in accordance with OECD Guideline No. 202.

Groups of twenty Daphnia were exposed for 48 hours to five concentrations of ZK 24. 942 dispersed in water under semi-static conditions. The incidence of immobilization was recorded for each test and control group at 24 and 48 hours and the following values determined:

EC50 (24 h): 2.6 mg/L (95 % confidence limits 2.1 -3.2 mg/L)

EC50 (48 h): 1.3 mg/L (95 % confidence limits 1.2 -1.4 mg/L)

NOEC was 0.56 mg/L at 24 and 48 h.

Description of key information

Tetrabutyltin was determined to have a 48 hour EC50 of 1.3 mg/L with respect to daphnia magna.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.3 mg/L

Additional information

Four studies are available to address this endpoint.

Short-term toxicity to aquatic invertebrates.001: Daphnia magna: EC50 (48 h): 1.3 mg/L (95% confidence limits 1.2 -1.4 mg/L), 48 h NOEC 0.56 mg/L

Short-term toxicity to aquatic invertebrates.002: The 24 hr EC50 (immobilization) for daphnia exposure to tetrabutyltin was 1.55 mg/L

Short-term toxicity to aquatic invertebrates.003: Daphnia magna: EC50 2.0 µg/L

Short-term toxicity to aquatic invertebrates.004: The LC50s for Cladocera and Anostraca exposure to tetrabutyltin are 776 and 53 µg/L, respectively

Short-term toxicity to aquatic invertebrates.001was determined as the key study for this endpoint as it was conducted to an OECD guideline, complied with GLP and was assigned a reliability rating of 2, according to the criteria of Klimisch et al. (1997). This was considered the most reliable study as all supporting studies have a reliability rating of 4, according to the criteria of Klimisch et al. (1997).