Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Key values for acute aquatic toxicity

Algae: 72h-ErC50 (Pseudokirchneriella subcapitata; growth rate; geometric mean measured) 10.1 (95% CI: 9.38 -10.9) mg/L;

Daphnia: 48h-EC50 (Daphnia magna, immobilisation; measured) 8 mg/L (95% CI: 6.1-10.8 mg/L);

Fish: 28-days LC50 (Danio rerio, mortality; analytically verified) > 10 mg/L;

 

Key value for chronic aquatic toxicity

Algae: 72h-EC10 (Pseudokirchneriella subcapitata; growth rate; geometric mean measured) 4.64 (95% CI: 3.97 – 5.53) mg/L;

 

Toxicity to microorganisms

STP microorganisms: 2h-NOEC (Nitrosomonas sp., Nitrobacter sp., inhibition of nitrification rate) 100 mg/L;

Additional information

Short-term and long-term toxicity

Fish:

According to the key study for acute toxicity to fish, the 28-d LC50 for acute fish toxicity is greater than 10 mg/L (OECD 204; Danio rerio; analyt. verified; Hoechst 1991).

The supporting study delivered a 96-h LC50 of 16.3 mg/L (OECD 203; Oryzias latipes; nominal; NITE, 2002).

 

There are no valid long-term toxicity results for fish available. Fish are not the most sensitive organisms. Therefore and for reasons of animal welfare, a long-term toxicity study in fish is not provided.

Aquatic invertebrates:

In the reliable key study, the 48-h EC50 for acute effects of tributylamine on aquatic invertebrates was experimentally determined to be 8 mg/L (OECD 202; measured; Daphnia magna; Pedersen, 2003).

There are no valid long-term toxicity results for aquatic invertebrates available. As the chemical safety assessment does not indicate the need for further testing, no long-tern toxicity tests on aquatic invertebrates is provided.

 

Algae:

A valid OECD 201 (GLP; RL 1) study with Pseudokirchneriella subcapitata over 72 hours was performed (Herrmann, 2018) with analytical verification of test item concentrations.

The following ECx -values with 95% confidence intervals were determined (based on geometric mean measured test item concentrations):

ErC50: 10.1 (9.38 -10.9) mg/L

EyC50: 5.13 (4.14 -7.26) mg/L

ErC10: 4.64 (3.97 – 5.53) mg/L

The NOEC-values for inhibition of growth rate and yield after 72 hours were 1.65 mg/L and 0.154 mg/L, respectively.

 

Microorganisms:

The results from the nitrification inhibition study were selected as key value for the derivation of the PNEC stp. Tributylamine does not disturb nitrification: 2-h NOEC: 100 mg/L (Nitrosomonas sp., Nitrobacter sp.; nominal; no guideline followed; Hockenbury and Grady, 1977).

 

The second reliable study (key study) was a respiration inhibition test conducted with activated sludge (predominantly domestic). No guideline was followed. The substrate was glucose. The 7-d EC05 was 100 mg/L (read across from tributylammonium chloride; Yoshimura et al., 1980).

  

Overview on key and supporting ecotoxicity studies

Endpoint

Species

Value [mg/L]

Reliability

Remarks

Source

Fish

28-d LC50

Danio rerio

> 10

1

key study

nominal,

analyt. verified

Hoechst AG (1991)

96-h LC50

Oryzias latipes

16.3

2

supp. study

nominal

NITE (2002)

96-h LC50

Leuciscus idus

> 100 - < 500

2

supp. study

pH-adjusted;

nominal

BASF AG (1987)/

(BASF SE (2011)

Aquatic invertebrates

48-h EC50

Daphnia magna

8

2

key study

analytically verified concentrations;
semi-static

Pedersen (2003)

Aquatic algae

72-h ErC10 (95% C.I.)

Pseudokirchneriella subcapitata

4.64 (3.97 – 5.53)

1

key study

geometric mean measured; growth rate

Herrmann (2018)

 

72-h ErC50 (95% C.I.)

 

Pseudokirchneriella subcapitata

10.1 (9.38 -10.9)

 

1

key study

geometric mean measured; growth rate

72-h EbC10

Desmodesmus subspicatus (reported as Scenedesmus subspicatus)

1.4

2

supp. study

test solutions neutralised; nominal; presumably biomass

Nusch (1987), cited in Amann et al. (1987/1988)

72-h EbC50

Desmodesmus subspicatus (reported as Scenedesmus subspicatus)

8.2

2

supp. study

test solutions neutralised; nominal; presumably biomass

Microorganisms

7-d EC05

Activated sludge, domestic

100

2

key study

Read-across to HCl salt of tributylamine used as test item; nominal

Yoshimura et al. (1980)

2-h NOEC

Nitrosomonas sp. and Nitrobacter sp.

100

2

key study

nominal

Hockenbury & Grady (1977)

 

It can be concluded that tributylamine is acutely toxic to aquatic organisms. TBA has been found to be stable in test solutions, based on TOC measurements in screening tests (without organisms) according to OECD 201 (>80% for 96 h) and OECD 202 (>80% for 48 h).