Phthalic acid

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

inhibition of germination

GLP compliance:

no

Analytical monitoring:

no

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

seed germination/root elongation toxicity test

Study type:

laboratory study

Substrate type:

other: agar media

Total exposure duration:

3 d

Species:

Lactuca sativa

Duration:

3 d

Dose descriptor:

EC50

Effect conc.:

731 other: mg/l

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: germination

The result is given as LC50 =  4.4 mmol/l at pH 2.80.

Executive summary:

Reynolds (1975) examined pH restraints on lettuce (Lactuca sativa) fruit germination. The EC50 of phthalic acid was 731 mg/l at pH 2.80.

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

short-term, splitroot experiments

GLP compliance:

not specified

Species:

other: other terrestrial plant: Gossypium hirsutum L.

Test type:

vegetative vigour test

Study type:

laboratory study

Substrate type:

other: soil-solutions

Phthalic acid showed essentially no root-protection capacity at acid 
 levels up to 50 µmol/L.

Reference 3

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

phytotoxicity test

GLP compliance:

not specified

Species:

other: other terrestrial plant: Lycopersicon esculentum Mill, cv TVR-2

Test type:

vegetative vigour test

Study type:

laboratory study

Substrate type:

not specified

Beside other organic acids the phthalic acid was identified as one of 
the  phytotoxic acids.

Reference 4

Endpoint:

toxicity to terrestrial plants: long-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

The study on toxicity of phthalic acid towards terrestrial plants cannot be used for assessment. Therefore, the equilibrium partitioning method (EPM) is applied to assess the hazard to soil organisms.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

731 mg/kg soil dw

Additional information

For phthalic acid only one reliable toxicity test on terrestrial plants is available. Reynolds (1975) examined pH restraints on lettuce (Lactuca sativa) fruit germination on agar media treated with the test substance. An EC50 of 731 mg/l at pH 2.80 was determined.

The scope of the terrestrial effects assessment under the adopted REACH regulation is restricted to soil organisms in a narrow sense and does not actually include adverse effects on soil functions that are only indirectly linked to the biota in soils. The test described above, was designed assessing the influence of phthalic acid on germination and growth on agar treated with the substance. As no soil was used in the test standardisation of soil effect data to given soil parameters is not possible. Further, converting the result to an appropriate dimension is not applicable. Therefore the result should not be used for the hazard assessment. Nevertheless, the obtained effect values indicate that phthalic acid is of low toxicity to terrestrial plants.