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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: no glp, no guideline a available (older than guideline and glp)
Qualifier:
no guideline followed
Principles of method if other than guideline:
Primary activity was measured by the amount of 14C uptake by algae over a 48h periode. The concentration causing a 50% reduction in productivity (median inhibition activity, IC 50) was estimated.
The effect of tin on reproduction (growth) was measured spectrophotometrically. One ml of the incolum was added to 49 k CHU-10 medium with and without tin compounds.
GLP compliance:
no
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
other: scendesmus quadricauda
Test type:
static
Water media type:
freshwater
Limit test:
no
Remarks on exposure duration:
see table
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
50 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: dissolved Sn
Basis for effect:
other: 14C uptake
Duration:
4 h
Dose descriptor:
EC50
Effect conc.:
14 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: dissolved Sn
Basis for effect:
cell number
Duration:
4 h
Dose descriptor:
EC50
Effect conc.:
50 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: dissolved Sn
Basis for effect:
cell number
Duration:
4 h
Dose descriptor:
EC50
Effect conc.:
12 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: dissolved Sn
Basis for effect:
cell number
Duration:
8 d
Dose descriptor:
NOEC
Effect conc.:
14 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Remarks:
Sn
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
NOEC (Reproduction) = 12 mg Sn/ L = 21.7 mg SnSO_4 7 l (stabilisation with humic acid instead of EDTA); measurement of Sn total
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: no glp, good documentation
Qualifier:
no guideline required
Principles of method if other than guideline:
The cyanobacterium was exposed to tin compounds in the liquid modified medium Z (with lowered phosphate and bicarbonate contents by 50% compared to the original cultivation medium), of initial pH 7.2, or (dependent on the experiment) buffered with 10 nM Hpes/NaOH and adjusted to an appropriate pH value (7-9).
Inorganic tin was used in the forms of stannous (SnCl_2 x 2H_2O) and stannic chlorides(SnCL_4 x 5H_2o) in the range 1-10 mg Sn/L. The stock solution of humic acid was added to the cyanobacterium cultures to the final concentration of 20 mg/KL. The solution of metal and humic acid ware prepared separately and sterilized by passing through membrane filters (0.45 µm).
Growth of the cyanobaterium cultures was recorded by measuring the optical density at 650 nm and chlorophyll a content.
All experiments were carried out at least in triplicate at 23°C in an illumination regime: 16h light / 8h dark.
GLP compliance:
no
Analytical monitoring:
yes
Vehicle:
yes
Test organisms (species):
other: synechocystis aquatilis
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
5 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: Sn(II)
Basis for effect:
growth rate
Remarks on result:
other: pH 7.2
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
10 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: Sn(II)
Basis for effect:
growth rate
Remarks on result:
other: pH 7.2
Validity criteria fulfilled:
yes
Conclusions:
NOEC SnSO_4 = 9.1. mg/L
EC50 SnSO_4 = 18.2 mg/L

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
18.2 mg/L
EC10 or NOEC for freshwater algae:
9.1 mg/L

Additional information