4-hydroxy-3-methoxycinnamic acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

The objective of this study was to screen a wide range of commercially available natural compounds for selective cyanobacterial algicides. Some of the natural compounds screened in this study may be produced or released during lignin decomposition. Other natural compounds selected for screening in this study possess similar mechanisms of toxicity as those of several synthetic compounds that were previously found to be selectively toxic towards Oscillatoria chalybea.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

other: Pseudokirchneriella subcapitata; Pediastrum simplex; Anabaena sp and Oscillatoria cf. chalybea

Details on test organisms:

- Selenastrum capricornutum, a representative species for green algae (provided by Dr. J. C. Greene, USEPA, Corvallis, OR)
- greenalga Pediastrum simplex UTEX #LB 1601 (Culture Collection of Algae,University of Texas, Austin, TX).
- Anabaena sp. LP 691 (obtained from George Izaguirre, TheMetropolitan Water District of Southern California, La Verne, CA)
- cyanobacterium Oscillatoria cf. chalybea

Test type:

static

Water media type:

freshwater

Total exposure duration:

5 d

Test temperature:

25 to 27°C

Nominal and measured concentrations:

Nomimal concentration between 1µM and 1000µM

Key result

Duration:

5 d

Dose descriptor:

LOEC

Effect conc.:

194 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Pseudokirchneriella subcapitata; Pediastrum simplex; Anabaena sp

Key result

Duration:

5 d

Dose descriptor:

LOEC

Effect conc.:

0.194 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Oscillatoria chalybea

Duration:

5 d

Dose descriptor:

EC100

Effect conc.:

194 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Pseudokirchneriella subcapitata; Anabaena sp and Oscillatoria cf. chalybea

Duration:

5 d

Dose descriptor:

EC100

Effect conc.:

> 194 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Pediastrum simplex

Details on results:

The phenolic compounds, ferulic acid and sinapic acid, were inhibitory to O. cf. chalybea at 1 and 10 µM, respectively, based on LOEC results. Ferulic acid had a high differential sensitivity based on LOEC results and, therefore, was the most selectively toxic phenolic compound screened. However, ferulic acid was not selectively toxic towards another cyanobacterium, Anabaena sp. LP 691.
Therefore, ferulic acid might be of use in selectively controlling the growth of particular species of cyanobacteria such as O. cf. chalybea, but could not be used as a broad-spectrum cyanobacterial algicide.


Species: Pseudokirchneriella subcapitata; Pediastrum simplex; Anabaena sp. LOEC (5 d) = 194 mg/L (population growth rate)
Species: Oscillatoria chalybea LOEC (5 d)= 0.194 mg/L (population growth rate)

Validity criteria fulfilled:

not applicable

Remarks:

no guideline followed

Conclusions:

For the Species: Pseudokirchneriella subcapitata; Pediastrum simplex; Anabaena sp., the LOEC (5 d) was found to be 194 mg/L (1000 µM) based on the population growth rate.
For the Species: Oscillatoria chalybea, the LOEC (5 d) was 0.194 mg/L (1 µM) based on the population growth rate.

Executive summary:

In this study, the main objective was to screen a wide range of commercially available natural compounds for selective cyanobacterial algicides. Thus, the toxiciy of several compounds including Ferulic acid towards algal culture i.e.cyanbacteria and green algae (Selenastrum capricornutum) was investigated.

For the Species: Pseudokirchneriella subcapitata; Pediastrum simplex; Anabaena sp., the LOEC (5 d) was found to be  194 mg/L (1000 µM) based on the population growth rate.

For the Species: Oscillatoria chalybea, the LOEC (5 d) was 0.194 mg/L (1 µM) based on the population growth rate.

Description of key information

Two studies involving a standard algae species were found (Pseudokirchneriella subcapitata and Microcystis aeruginosa).

In the Rui et al 2016 study,  the authors investigated the effects of allelochemical Ferulic acid on a series of physiological and biochemical processes of blue-green algae Microcystis aeruginosa, in order to find sensitive diagnostic variables for allelopathic effects.

To obtain the dose response effects of Ferulic acid on M. aeruginosa, the exposure medium were prepared by adding Ferulic acid in flasks containing MA medium at a series of concentrations: 60.1, 91.2, 135.8, 201.8, 302.6, 450.1, 673.2 and 1003 mg/L.

Several biological effect are investigated as cell density but also the membrane integrity, Membrane potential, Esterase activity Chlorophyll a content and Interferences on photosynthetic activities.

Under the tests conditions, Ferulic acid exposure inhibited the growth of blue-green algae Microcystis aeruginosa. The 48h-EC50 and the 96h-EC50 were 442 mg/L and 211 mg/L (i.e. 2.28 mM and 1.09 mM respectively) based on the biomass (cell density). Furthermore this algae cell density was significantly suppressed by Ferulic acid (in the range 0.31 -5.17 mM) only after 48 h exposure therefore the LOEC is determined to be 60.1 mg/L

The second study is a publication from 1998 (Schrader et al 1998) in which the main objective was to screen a wide range of commercially available natural compounds for selective cyanobacterial algicides. In this study, the toxiciy of several compounds including Ferulic acid towards algal culture with cyanbacteria (Anabaena sp and Oscillatoria chalybea ) and green algae (Selenastrum capricornutum and Pediastrum simplex) was investigated.

Thus, for the Species: Pseudokirchneriella subcapitata, Pediastrum simplex and Anabaena sp., the LOEC (5 d) was found to be 194 mg/L (1000 µM) based on the population growth rate. For the Species Oscillatoria chalybea, the LOEC (5 d) was 0.194 mg/L (1 µM) based on the population growth rate. According to the high differential sensitivity between the cyanobacteria Oscillatoria chalybea and the other species (Pseudokirchneriella subcapitata, Pediastrum simplex and Anabaena sp), and also the other study available ( Rui et al 2016), its LOEC is not considered as representative of the algal or cyanobacteria.

Therefore as the Pseudokirchneriella subcapitata is one of the standard species recognized and the study of scharder closer to the OECD guideline test conditions, its LOEC was taken as key value (i.e. EC50 > 194 mg/L).

Key value for chemical safety assessment

EC50 for freshwater algae:

194 mg/L