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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: non GLP, non Guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
not specified
GLP compliance:
not specified
Analytical monitoring:
no
Details on sampling:
no sampling
Vehicle:
no
Details on test solutions:
not indicated
Test organisms (species):
Nitocra spinipes
Details on test organisms:
Not fed during the study.
Only adult animals , harvested from 3 to 6 weeks old cultures were used.
Test type:
static
Water media type:
brackish water
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
no post exposure period
Hardness:
not indicated
Test temperature:
10°C
pH:
7.8
Dissolved oxygen:
not indicated
Salinity:
0.7 %
Nominal and measured concentrations:
at least six concentrations with one control (not specified)
Details on test conditions:
N. spinipes (2x 10 animals) were tested in 15 ml standard laboratory test tubes containing 10 ml of brackish water at 10°C. Mortality was recorded after 96 h under a low power microscope with strong illuminations.
Reference substance (positive control):
no
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
92.5 g/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95% CL: 26.8 - 305.0
Details on results:
no details given
Results with reference substance (positive control):
no reference substance
Reported statistics and error estimates:
Graphical analysis according to Litchfield and Wilcoxon.
Validity criteria fulfilled:
yes
Conclusions:
The LC50 of methenamine in Nitocra spinipes (brackish water) was determined to be 36 g/L.
Executive summary:

The 96 hr-acute toxicity of methenamine to Nitocra spinipes was studied under static conditions. Nitocra were exposed to control and at least 6 test concentrations for 96 hr. Mortality/immobilization were observed at test termination. The 96 hour LC50 was 92.5 g/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with saltwater invertebrates.

Results Synopsis

Test Organism Age: adult

Test Type: Static

LC50: 92.5 g/L (95% C.I. : 26.8 to 305.0 g/L

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: non GLP
Qualifier:
according to guideline
Guideline:
other: ASTM Committee on Water Quality, 1979: Proposed standard practice for conducting static acute toxicity tests on process wastewaters with Daphnia.
Deviations:
not specified
GLP compliance:
not specified
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
Chemical was of reagent quality.
Analytical monitoring:
no
Details on sampling:
no sampling
Vehicle:
no
Details on test solutions:
Reconstituted water used.
Test organisms (species):
Daphnia magna
Details on test organisms:
Obtained from Ann Arbor Biological Center.
Fed on a suspension of dry activated yeast and Purina Trout Chow.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
no post exposure period
Hardness:
100 mg/l CaCO3
Test temperature:
not indicated
pH:
7.6
Dissolved oxygen:
not indicated
Salinity:
freshwater was used
Nominal and measured concentrations:
nominal: 15, 20, 30 , 40 g/L
Details on test conditions:
The tests were conducted in replicates of four by placing five young daphnids (1-3 days old) into each of 250 ml Erlenmeyer flasks containing 200 ml of test solution. The number of organisms not showing movement within 30 sec were presumed dead and thus were removed. Readings were taken at 2, 8, 24, and 48 h.
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
36 g/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95 % CL: 29.9 - 43.4
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
15 g/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
no details given
Results with reference substance (positive control):
no reference substance
Reported statistics and error estimates:
LC50 was calculated by probit analysis (slope of probit line: 5.29)
Validity criteria fulfilled:
yes
Conclusions:
The LC50 of methenamine in Daphnia magna (freshwater) was determined to be 36 g/L.
Executive summary:

The 48 hr-acute toxicity of methenamine to Daphnia magna was studied under static conditions. Daphnids were exposed to control and test chemical at nominal concentration of 15, 20, 30 and 40 g/L for 48 hr. Mortality/immobilization were observed daily. The 48 hour LC50 was 36 g/L. The 48 hr NOEC based on mortality/immobilization was 15 g/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

Results Synopsis

Test Organism Age : 1-3 days

Test Type: Static

LC50: 36 g/L (95% C.I. : 29.9 to 43.4 g/L

NOEL: 15 g/L

Probit Slope: 5.29

Description of key information


The LC50 of methenamine in Daphnia magna (freshwater) was determined to be 36 g/L. The LC50 of methenamine in Nitocra spinipes (brackish water, saltwater) was determined to be 92.5 g/L.


Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Dose descriptor:
EC50
Effect concentration:
36 000 mg/L

Marine water invertebrates

Marine water invertebrates
Dose descriptor:
EC50
Effect concentration:
92 500 mg/L

Additional information

Key-Studies:

- The 48 hr-acute toxicity of methenamine to Daphnia magna (Walton, 1980) was studied under static conditions. Daphnids were exposed to control and test chemical at nominal concentration of 15, 20, 30 and 40 g/L for 48 hr. Mortality/immobilization were observed daily. The 48 hour LC50 was 36 g/L. The 48 hr NOEC based on mortality/immobilization was 15 g/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

- The 96 hr-acute toxicity of methenamine to Nitocra spinipes was studied under static conditions. Nitocra were exposed to control and at least 6 test concentrations for 96 hr. Mortality/immobilization were observed at test termination. The 96 hour LC50 was 92.5 g/L.

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with saltwater invertebrates.

Based on the available data, no toxicity towards fresh and saltwater invertebrates species even at concentrations > 92000 mg/L, which by far exceeded the recommended limit concentration of OECD guidelines (100 mg/L) clearly indicate, that methenamine is not toxic at all towords saltwater or freshwater invertebrates.