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Ecotoxicological information

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:
toxicity to aquatic plants other than algae
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards, well documented and acceptable for assessment
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1984

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: ASTM, Proposed New Standard Practice for Conducting Static Toxicity Tests with Duckweed
Deviations:
not specified
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material: anhydrous AlCl3
- Analytical purity: 99.7%
- Source: MCB Manufacturing Chemists, Inc.
- Lot/batch No.: B7N14
- All other template details: Not reported
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: all exposures including control
- Sampling method: samples were collected before, at the beginning of, and at the end of the 96 hr exposure. Samples (15-20 mL) were collected midway between the surface and bottom of the water column in the center of each exposure chamber. A 30 mL adjustable-volume glass-teflon syringe was rinsed three times with the exposure water prior to collecting a sample.
- Sample storage conditions before analysis: All samples were immediately acidified to 1% (v/v) with concentrated nitric acid (Baker Instra analyzed Lot No: 340040). Two mL of potassium chloride solution (95 g KCl/L) was added per 100 mL sample, as suggested in method 202.1. Methods for Chemical Analysis of Water and Wastewater (U.S. EPA, 1979).

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Exposure and control tanks were prepared a minimum of 48 hr in advance of organism introduction to the tanks. The water volume was measured, then added to each exposure tank, and aluminum introduced from a 50,000 mg/l stock solution. Daily adjustments of pH were necessary in many of the exposures. Tests run at pH values above neutrality declined in pH in proportion to the total aluminum present. Controls dropped the least or not at all. Tests run at a pH below neutrality (6.5 nominal) rose in pH in all test chambers.
- Evidence of undissolved material: a precipitate was readily apparent at concentrations of 3.12 mg/L or above
- All other template details: Not reported

Test organisms

Test organisms (species):
Lemna minor
Details on test organisms:
TEST ORGANISM
- Common name: duckweed
- Source: A stock culture of Lemna minor was obtained from Dr. W. Wang, Water Quality Section, Illinois State Water Survey, Peoria, Illinois.
- All other template details: Not reported

ACCLIMATION
- Acclimation period: 7 days
- Culturing media and conditions: maintained in dilution water
- Any deformed or abnormal cells observed: not reported

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
Not reported

Test conditions

Hardness:
47.4 mg/L as CaCO3
Test temperature:
24 ± 2 degrees C
pH:
two pH levels: 7.6 ± 0.05 and 8.2 ± 0.05
Dissolved oxygen:
Not reported
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal test concentrations (mg/L): 0 (control), 3.12, 6.25, 12.5, 25.0, 50.0
Measured concentrations (mg/L): <0.3, 2.8, 5.9, 11.4, 23.2, 45.7
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL beaker
- Material, size, headspace, fill volume: 200 mL of test solution in each beaker
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter):
- No. of colonies per replicate: 10
- No. of fronds per colony: 2
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- All other template details: Not reported

GROWTH MEDIUM: Not reported

SEDIMENT USED: Not applicable

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Superior water collected from a tap on the City of Cloquet, MN raw water intake in the City of Superior, WI. The source of the water was from approximately 3200 meters offshore on the lake bottom.
- Total solids: 61 ± 5 mg/L
- Particulate matter (total suspended solids): <1.0 mg/L
- Chloride: 1.5 ± 0.42 mg/L
- Alkalinity: 41.6 ± 1.27 mg/L as CaCO3
- Culture medium different from test medium: no
- Intervals of water quality measurement: measured on each batch of water used
- All other template details: Not reported

OTHER TEST CONDITIONS
- Sterile test conditions: not reported
- Adjustment of pH: Exposure solutions were pH adjusted using either NaOH or HCl of ACS grade purity if the pH differed from the desired test pH by more than 0.2 units.
- Photoperiod: not reported
- Light intensity and quality: 400 ± 40 ft. candles

EFFECT PARAMETERS MEASURED : total number of fronds
- Determination of frond number: nor reported, assumed manual counting

RANGE-FINDING STUDY: Not reported
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
> 45.7 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Basis for effect:
frond number
Remarks on result:
other: Unbounded NOEC for both pH levels
Details on results:
- Other: pH dropped during the test from 0.2 to 1.0 pH units. The 96 hr water column concentrations of Al were all at or below the detection limit with the exception of two questionable values.
- All other template details: Not reported
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
Not reported

Any other information on results incl. tables

TABLE 3. Frond Production by Duckweed (Lemna minor) Exposed for 96 Hr to A13+ in Lake Superior Water at Initial pH Values of 7.6 and 8.2.

Al3+ Concentration (mg/L)

 

Nominal

0

3.12

6.25

12.5

25

50

 

Total Measured 1

<0.3

2.8

5.9

11.4

23.2

45.7

pH 7.6

Mean Number of Fronds (± SD)

39.0 ± 3.5

37.0 ± 2.0

38.0 ± 1.7

38.7 ± 1.2

36.7 ± 2.5

38.3 ± 1.2

 

Percent Effect

-

10.5

5.3

1.6

12.1

3.7

pH 8.2

Mean Number of Fronds (± SD)

42.7 ± 0.6

36.3 ± 3.8

37.0 ± 2.6

38.7 ± 2.9

39.3 ± 3.2

40.7 ± 1.2

 

Percent Effect

-

28.2

25.1

17.6

15

8.8

 

1- Total measured Al is the initial amount present in the water column prior to pH adjustment and the start of the test. No precipitate was observed.

Applicant's summary and conclusion

Conclusions:
96 hr exposure of Lemna minor to aluminium chloride concentrations up to 45.7 mg/L resulted in no significant effects on frond number compared to controls at a pH of 7.6 or 8.2.