4-(1,1,3,3-tetramethylbutyl)phenol

Toxicity to aquatic plants other than algae

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

In accordance with Regulation (EC) 1907/2006 Annex XI (1.5) and the relevant ECHA guidance documents, the substances detailed in the table below are grouped for the purposes of read across to reduce the need for unnecessary repeat testing on the basis that the substances are similar on the basis of a common functional groups.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.901 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

frond number

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

2.08 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

frond number

Reported statistics and error estimates:

- NOEC and LOEC determined by one-way analysis of variance (ANOVA)

Validity criteria fulfilled:

yes

Conclusions:

The read across for 4-tert-octylphenol (CAS: 140-66-9); is based upon the analogous substances to which basic form, degree of substitution of functional groups is not considered to effect the proposed read across for the endpoint of Toxicity to aquatic plants other than algae. Based on the information available for the read across substances, the substance is expected to be toxic to aquatic plants other than algae.

Reference 2

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not provided

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Klimisch 2b. Guideline study with acceptable restrictions which do not impair the overall conclusion from the data.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: ASTM 1991. E1415-91 Standard Guide for Conducting Static Toxicity Tests with Lemna gibba.

Deviations:

yes

Remarks:

Test was performed with alternate species. Plants at 2-frond stage were used rather than three or four frond stage recommended by ASTM. ASTM requirements for duration, frond production, light intensity or uniformity were not met.

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: stock solutions generated with a liquid/liquid equilibrator
- Controls: dilution water control

Test organisms (species):

Lemna minor

Details on test organisms:

TEST ORGANISM
- Common name: common duckweed
- Source: ERL-D culture
- Age: two-frond stage
- Nutrients: supplied throughout test

ACCLIMATION
- Culturing media and conditions: grown with nutrient media in static culture chamber with weekly nutrient additions

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

- Total hardness: 175 +/- 28.7 mg/L as CaCO3

Test temperature:

- Temperature: 22.8 +/- 0.3 °C

pH:

- pH: 8.25 +/- 0.13

Dissolved oxygen:

- Dissolved O2: 7.6 +/- 0.6 mg/L

Salinity:

NA

Nominal and measured concentrations:

- Test concentrations: <0.088, 0.109, 0.375, 0.901, and 2.080 mg/L measured

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 2.4 L test solution per chamber
- Type of flow-through: proportional mini-diluter system
- No. of colonies per vessel: 22 frond plants per exposure concentration
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 1

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: City of Superior, WI municipal water supply. Dechlorinated by passing through activated charcoal column and addition of sodium sulphite. Passed through cation exchange resin to remove heavy metals.
- Alkalinity: 105 +/- 22.6 mg/L as CaCO3

OTHER TEST CONDITIONS
- Light intensity and quality: did not meet ASTM

EFFECT PARAMETERS MEASURED
- Determination of frond number: manual counting daily

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.901 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

frond number

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

2.08 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

frond number

Reported statistics and error estimates:

- NOEC and LOEC determined by one-way analysis of variance (ANOVA)

Validity criteria fulfilled:

yes

Conclusions:

The NOEC for inhibition of frond development was 0.901 mg nonylphenol/L. The LOEC for inhibition of frond development was 2.08 mg nonylphenol/L. No further conclusions drawn.

Executive summary:

Brooke (1993).EPA: Klimisch 2b. 

In a 96 hour acute toxicity study, Lemna minor (ERD-L culture) was exposed to nonylphenol at final measured test concentrations of <0.088, 0.109, 0.375, 0.901, and 2.080 mg nonylphenol/L under flow through conditions following ASTM guidelines. This test did not meet all ASTM requirements for duration or frond development, and light intensity, but was conducted for a sufficient period of time to observe effects. The NOEC for inhibition of frond development was 0.901 mg nonylphenol/L.  The LOEC for inhibition of frond development was 2.08 mg nonylphenol/L. 

 

There were no compound related phytotoxic effects.

 

Brook (1993) is classified as acceptable and satisfies the guideline requirements for a supporting acute Lemna minor toxicity test. The NOEC and LOEC values reported in Brooke (1993) are not comparable toEC₅₀and other point estimates of effects. The NOEC and LOEC information is provided to support the findings in key studies Scholz (1992) and Ward and Boeri (1990).

 

Results Synopsis

 

Test Organism: Lemna minor– two frond stage

Test Type: Flow through

 

96 hEC₅₀:  none                                95% C.I. :  none

96 h EC₅₀/IC₅₀: none                         95% C.I. :  none

NOEC:   0.901 mg nonylphenol/L       Probit Slope:  none

LOEC:   2.08mg nonylphenol/L 

Endpoint(s) Effected:  Frond development

 

Brook (1993 ) was selected as a supporting study because nonylphenol toxicity information is presented for a common aquatic plant species other than algae in addition to the algae Selenastrum capricornutum. Results of this study support the finding of Key Study Ward and Boeri (1990).

Description of key information

The NOEC for inhibition of frond development was 0.901 mg nonylphenol/L. The LOEC for inhibition of frond development was 2.08 mg nonylphenol/L. No further conclusions drawn.

Key value for chemical safety assessment

EC10 or NOEC for freshwater plants:

0.901 mg/L