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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
Sulfuryl dichloride hydrolyzes slowly in moist air and reacts violently with water, forming hydrochloric acid and sulfuric acid.

2 H2O + SO2Cl2 → 2 HCl + H2SO4

Hydrogen chloride is a colourless gas which has a pungent odor, and has a vapour pressure of 42,200 hPa at 20°C and a water solubility of 823 g/L at 0°C. Its aqueous solution (called hydrochloric acid) possesses strong acidity. Hydrogen chloride is readily dissociated in water into hydrated protons and chloride ion. Sulfuric acid is a strong mineral acid that dissociates readily in water to sulfate ions and hydrated protons, and is totally miscible with water.
Cross-reference
Reason / purpose:
read-across source
Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
Sulfuryl dichloride hydrolyzes slowly in moist air and reacts violently with water, forming hydrochloric acid and sulfuric acid.

2 H2O + SO2Cl2 → 2 HCl + H2SO4

Hydrogen chloride is a colourless gas which has a pungent odor, and has a vapour pressure of 42,200 hPa at 20°C and a water solubility of 823 g/L at 0°C. Its aqueous solution (called hydrochloric acid) possesses strong acidity. Hydrogen chloride is readily dissociated in water into hydrated protons and chloride ion. Sulfuric acid is a strong mineral acid that dissociates readily in water to sulfate ions and hydrated protons, and is totally miscible with water.
Reason / purpose:
read-across source
Qualifier:
no guideline followed
Principles of method if other than guideline:
The effect of sulfuric acid addition for several years (1976 to 1983) in a natural (cold water) Canadian “Lake 223” was assessed in aquatic species populations. From an initial level of about 6.7, the pH was lowered at a pH rate of about 0.5 pH units a year (6.49 – 6.13 - 5.93 – 5.64 – 5.59) until it reached an average pH 5.1 and was held there for 3 years. This lake was one of the lakes of “ELA” (Experimental Lake Area) in Canada, where a set of natural lakes was selected as representative for a natural non-polluted environment. The phytoplankton community structure was also studied, giving a NOEC of pH 5.6 (0.13 mg/l) (chlorophyte increase and species shift to large inedible Gymnodium sp.). This NOEC integrates not only algae growth rate, but also consumption by invertebrates and fish, and also effects of successive one year exposures to pH 6.49, 6.13, 5.93
GLP compliance:
no
Test organisms (species):
other: Epilimnetic phytoplankton in a natural lake
Details on test organisms:
Chlorella mucosa (chlorophyte), Dinobryon sertularia, Mallomonas sp., Stichogloea sp., Uroglena sp. (chrysophycean species), Asterionella ralfsii(diatom), Gymnodinium sp., Peridinium inconspicuum (dinoflagellates) Chroococus minutus, Merismopedia sp. (cyanophyte)
Test type:
not specified
Key result
Duration:
52 wk
Dose descriptor:
EC50
Effect conc.:
0.13 mg/L
Nominal / measured:
nominal
Conc. based on:
other: measured pH
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
NOEC of pH 5.6 (0.13 mg/l) (chlorophyte increase and species shift to large inedible Gymnodium sp.)

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The effect of sulfuric acid addition for several years (1976 to 1983) in a natural (cold water) Canadian “Lake 223” was assessed in aquatic species populations. From an initial level of about 6.7, the pH was lowered at a pH rate of about 0.5 pH units a year (6.49 – 6.13 - 5.93 – 5.64 – 5.59) until it reached an average pH 5.1 and was held there for 3 years. This lake was one of the lakes of “ELA” (Experimental Lake Area) in Canada, where a set of natural lakes was selected as representative for a natural non-polluted environment. The phytoplankton community structure was also studied, giving a NOEC of pH 5.6 (0.13 mg/l) (chlorophyte increase and species shift to large inedible Gymnodium sp.). This NOEC integrates not only algae growth rate, but also consumption by invertebrates and fish, and also effects of successive one year exposures to pH 6.49, 6.13, 5.93
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test organisms

Test organisms (species):
other: Epilimnetic phytoplankton in a natural lake
Details on test organisms:
Chlorella mucosa (chlorophyte), Dinobryon sertularia, Mallomonas sp., Stichogloea sp., Uroglena sp. (chrysophycean species), Asterionella ralfsii(diatom), Gymnodinium sp., Peridinium inconspicuum (dinoflagellates) Chroococus minutus, Merismopedia sp. (cyanophyte)

Study design

Test type:
not specified

Results and discussion

Effect concentrations
Key result
Duration:
52 wk
Dose descriptor:
EC50
Effect conc.:
0.13 mg/L
Nominal / measured:
nominal
Conc. based on:
other: measured pH
Basis for effect:
growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
NOEC of pH 5.6 (0.13 mg/l) (chlorophyte increase and species shift to large inedible Gymnodium sp.)