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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
other: bibliography
Adequacy of study:
weight of evidence
Study period:
1986 to 1996
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Ledum palustre mother tincture is a UVCB and natural complex substance, and is assesed through constituents approach taking into account one the main constituent : ethanol present at 65%.
Qualifier:
according to guideline
Guideline:
other: Growth rate measured as chlorophyll content and biomass accumulation at concentrations of 0.05% (500 mg/l) and higher (range 500 to 10,000 mg/l).
Principles of method if other than guideline:
Growth rate measured as chlorophyll content and biomass accumulation at concentrations of 0.05% (500 mg/l) and higher (range 500 to 10,000 mg/l).
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
not specified
Details on test solutions:
Ethanol was tested three times at each concentration (0, 0.05, 0.1, 0.3, 0.5 and 1%).
Test organisms (species):
Chlorella vulgaris
Details on test organisms:
Cultivation method: Cultures were grown in Algal Assay Procedure (1971) medium in 500 ml flasks containing 250 ml algal suspension.
Cells were not removed from medium prior to measurement; cell density not given.
Controls consisted of algal suspensions without solvent in each experiment.
Test type:
not specified
Water media type:
not specified
Total exposure duration:
4 d
Remarks on exposure duration:
This duration is different than standard duration (72h or 96h) but this test was chosen because Chlorella vulgaris is the most sensitive species.
Hardness:
15 mg/l NaHCO3 and 12 mg/l K2HPO4
Test temperature:
21 +/- 1 deg C with continuous illumination at 100 microE/m^2-sec.
pH:
not described
Dissolved oxygen:
not described
Salinity:
not described
Conductivity:
not described
Nominal and measured concentrations:
Test design: Ethanol was tested three times at each concentration (0, 0.05, 0.1, 0.3, 0.5 and 1%).
Method of calculating mean measured concentrations: Only nominal concentrations were used.
Details on test conditions:
Cells removed before measurement: cells were not removed.
Biological observations:
+Cell density at each flask/each measuring point: Not given.
Reference substance (positive control):
not specified
Key result
Duration:
4 d
Dose descriptor:
EC50
Effect conc.:
1 000 mg/L
Nominal / measured:
meas. (not specified)
Basis for effect:
growth rate
Remarks on result:
other: Growth was inhibited 54% at an ethanol concentration of 1000 mg/l, the value approximating the EC50.Growth inhibition was 37% at 500 mg/l. Growth was significantly inhibited (p=0.05) at all concentrations of ethanol.
Details on results:
Growth was inhibited 48% at an ethanol concentration of 10,000 mg/l; this approximates the ErC50.
Validity criteria fulfilled:
not specified
Conclusions:
Growth was inhibited 48% at an ethanol concentration of 10,000 mg/l; this approximates the ErC50.
Executive summary:

Using CPL regulation criteria (1272/2008 regulation) for classification, ethanol is not toxic or harmful for algae.

Description of key information

DATA FOR ETHANOL

Two robust studies of 96-hr duration each give NOEC values of <500 mg/l for the growth rate end point in Chlorella vulgaris and Selenastrum capricornutum (El Jay, 1996). Corresponding EC 50 values were 1,000 mg/l and 10,000 mg/l. Another study conducted to a high standard in Chlamydomonas eugametos yielded a 48-hr EC 50  of 2000mg/l (Hess, 1980) and a study on Chlorella pyrenoidosa and a variety of algal species all gave EC 50 values greater than 1,000 mg/l (Cowgill, 1989; Hess, 1980; Stratton, 1987; Stratton, 1988). 

One study of 5 days duration in Skeletonema costatum gave a NOEC in the range 3,240 to 5,400 mg/l based on cell count and corresponding EC 50 values of 10,943-11,619mg/l). The authors (Cowgill, 1989) remark that using EPA criteria, ethanol can be judged non-toxic by this test and that ethanol was used as a carbon source stimulating growth of the alga before inhibition began.

All results are shown in the table 12 of UNEP publication (see below) :

 SPECIES  TEST PERIOD (in days)  EC50 (mg/L)
 Chlorella vulgaris  1000
 Lemna gibba  4432
 Lemna minor 7  3690
Selenastrum capricornatum  4  10000
 Chlamydomonas eugametos  2000
 Skeletonema costatum  10943 - 11619
 Chlorella pyrenoidosa 10   1180

DATA FOR LEDUM PALUSTRE MOTHER TINCTURE

With a dilution in water (ca 33%), EC 50 value of tincture mother can be estimated as EC50 of ethanol in a wort case so it can can be estimated greater than 1000 mg/l.

Using CPL regulation criteria (1272/2008 regulation) for classification, ledum palustre mother tincture is not toxic or harmful for algae.

Key value for chemical safety assessment

Additional information

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