Triphenyl phosphate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to standard guideline with acceptable modifications (pH of test media not stated) (also assessed by OECD)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

According to an OECD guideline 201: Alga, growth inhibition test (1984); modified

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

Stock solutions prepared in acetone

Test organisms (species):

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

Details on test organisms:

Algal inocula were obtained from actively growing axenic cultures of S. capricornatum, Cambridge Collection No. CCAP 278/4

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

120 h

Remarks on exposure duration:

LOEC values calculated at 72h

Post exposure observation period:

Not applicable

Hardness:

No data given

Test temperature:

22°C

pH:

No data given

Dissolved oxygen:

No data given

Salinity:

Not applicable

Nominal and measured concentrations:

0.05, 0.1, 0.5, 1.0 and 5.0 mg/l

Details on test conditions:

Tests conducted in Erlenmeyer flasks containing sterile culture medium, TPP added in acetone (<0.1ml/l medium).
Bolds basal medium (= BBM), OECD and EPA recommended media used in three separate tests
10E4 cells/ml

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.5 - 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 - 2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

BBM-Medium: 72 h-LOEC = 0.5 mg/l; OECD-Medium: 72 h-LOEC = 5 mg/l; US-EPA-Medium: 72 h-LOEC = 1 mg/l

Growth medium composition does affect the toxic values

obtained in standard algal toxicity tests. The observed
effects, however, were neither consistent nor predictable

Conclusions:

LOEC values of between 0.5 and 5.0 mg/l have been determined, depending on the culture medium used.

Executive summary:

A static study has been performed with S. capricornatum for TPP according to OECD guideline 201: Alga, growth inhibition test (1984); modified. The effect of three different media has been analyzed. After 72 h LOEC values between 0.5 and 5.0 mg/L have been determined, depending on the culture medium used.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: test procedure acc. to standard guideline with acceptable modifications (pH of test media not stated) (also assessed by OECD)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

According to OECD guideline 201: Alga, growth inhibition test (1984); modified

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

Stock solutions prepared in acetone

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Algal inocula were obtained from actively growing cultures of S. subspicatus, Cambridge Culture Collection No. CCAP 276/20

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

120 h

Remarks on exposure duration:

LOEC values calculated at 72h

Post exposure observation period:

Not applicable

Hardness:

No data given

Test temperature:

22°C

pH:

No data given

Dissolved oxygen:

No data given

Salinity:

Not applicable

Nominal and measured concentrations:

0.05, 0.1, 0.5, 1.0 and 5.0mg/l

Details on test conditions:

Tests conducted in Erlenmeyer flasks containing sterile culture medium, TPP added in acetone (<0.1ml/l medium).
Bolds basal medium (= BBM), OECD and EPA recommended media used in three separate tests
10E4 cells/ml

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.5 - 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 - 2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Details on results:

BBM-Medium: 72 h-LOEC = 0.5 mg/l, OECD-Medium: 72 h-LOEC = 5 mg/l, US-EPA-Medium: 72 h-LOEC = 1 mg/l

Growth medium composition does affect the toxic values
obtained in standard algal toxicity tests. The observed
effects, however, were neither consistent nor predictable

Conclusions:

LOEC values of between 0.5 and 5.0mg/l have been determined, depending on the culture medium used.
NOEC values between 0.25 and 2.5mg/l have been derived using a standard procedure.

Executive summary:

A static study has been performed with S. subspicatus for TPP according to OECD guideline 201: Alga, growth inhibition test (1984); modified. The effect of three different culture media has been analyzed. After 72 h LOEC values of between 0.5 and 5.0 mg/L have been determined, depending on the culture medium used. NOEC values between 0.25 and 2.5mg/l have been derived using a standard procedure.

Description of key information

The most critical values were obtained for Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) and Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) and the data reports of LOECs between 0.5 and 5.0 mg/L depending on the growth medium. While there was no NOEC in the publication this was calculated based on the method outlined in REACH Guidance document R.10 (2008), page 11, which explains that a LOEC may be divided by 2 to estimate the NOEC. This calculation results in a NOEC of 0.25 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.25 mg/L

Additional information

The influence of varying growth medium compositions on the toxicity of the test substance was investigated for three algae species. The authors do not state NOEC values. Due to the only slight effect shown in the figures demonstrating the LOEC growth graphs compared to the control, derived NOECs are given for this test, using the procedure cited  in the Technical Guidance Document by the EU for Risk Assessments. There, LOEC values of 10 to 20 % effect are halved to derive a NOEC (LOEC/2 =  NOEC).