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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 24-26, 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study without GLP or analytical confirmation
Justification for type of information:
Please see Category Approach
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)
Deviations:
no
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM- Common name: daphnid- Strain: - Source: SLI laboratory culture- Age at study initiation (mean and range, SD): <24 hours- Weight at study initiation (mean and range, SD): - Length at study initiation (length definition, mean, range and SD): - Valve height at study initiation, for shell deposition study (mean and range, SD): - Peripheral shell growth removed prior to test initiation: - Method of breeding: - Feeding during test - Food type: not fed - Amount: - Frequency: ACCLIMATION- Acclimation period:- Acclimation conditions (same as test or not): yes- Type and amount of food: combination of 2 mL Ankistrodesmus falcatus and 0.5 mL of trout food suspension- Feeding frequency: - Health during acclimation (any mortality observed): healthyQUARANTINE (wild caught)- Duration: - Health/mortality:
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
160 mg/L
Test temperature:
19-20 degrees C
pH:
8.2
Dissolved oxygen:
87-98 % of saturation
Nominal and measured concentrations:
0, 130, 220, 360, 600 and 1000 mg/L as active ingredient (nominal)
Details on test conditions:
TEST SYSTEM- Test vessel: - Type (delete if not applicable): open - Material, size, headspace, fill volume: 250 mL glass beakers filled with 200 mL test solution - Aeration: none- Type of flow-through (e.g. peristaltic or proportional diluter): - Renewal rate of test solution (frequency/flow rate):- No. of organisms per vessel: 5- No. of vessels per concentration (replicates): 4- No. of vessels per control (replicates): 1- No. of vessels per vehicle control (replicates):- Biomass loading rate: TEST MEDIUM / WATER PARAMETERS- Source/preparation of dilution water: fortified well water following published ASTM methods and filtered through a Amberlite XAD-7 resin column to remove any organic contaminants.- Total organic carbon: 1.5 mg/L- Particulate matter:- Metals: all less than limit of quantitation except 2.3 mg/L magnesium and 0.02 mg/L manganese - Pesticides: all less than limit of quantitation- Chlorine:- Alkalinity: 90-110 mg/L as CaC03- Ca/mg ratio: 3:1- Conductivity: 500-800 micromhos per centimeter- Culture medium different from test medium:- Intervals of water quality measurement: OTHER TEST CONDITIONS- Adjustment of pH:- Photoperiod: 16 hrs light and 8 hrs dark- Light intensity: 30-100 footcandles at the surfaceEFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilization at 24 hour intervalsTEST CONCENTRATIONS- Spacing factor for test concentrations: <2X- Justification for using less concentrations than requested by guideline: - Range finding study - Test concentrations: 0.10 - 100 mg/L as active ingredient - Results used to determine the conditions for the definitive study: no immobilization at any test concentration
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
other: immobility
Remarks on result:
other: no immobility observed at any test concentration
Results with reference substance (positive control):
no reference substance
Validity criteria fulfilled:
yes
Conclusions:
Test material not acutely toxic to daphnids at up to 1000 mg/L active ingredient

Description of key information

There are five short-term invertebrate studies for hydrotrope category substances. These include two GLP compliant studies (EPA OTS 797.1300 and EU Method C.2) and an OECD 202 study, all of which are highly reliable. The Key Study (Collins, 1993) reports an EC50 value for the hydrotropes of >1000 mg/L in the guideline GLP study with the test substance sodium xylenesulphonate.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1 000 mg/L

Additional information

A range of short-term data is available for aquatic invertebrates from >40.3 to > 1,020 mg/L corresponding to four Hydrotrope category substances. The key study is a 1993 USEPA Guideline study (EPAOTS 797.1300) Aquatic Invertebrate Acute Toxicity. The study was not conducted following GLP principles but there is considerable detail provided. Daphnids were exposed to five nominal test concentrations of sodium xylenesulphonate and immobility was monitored for 48 hours. The exposure was static and there was no analytical measurement. No immobilization was observed in the test concentrations and the nominal 48-hour EC50 was >1000 mg/L active substance.

In a supporting study, the 48 hour EC50 was 1020 mg/L measured active substance based on immobilization of 30% and 50% of the organisms in each of two replicate exposures at this concentration. The flow-through study (Ruetgers-Nease Corporation, 1994) with analytical measurements was conducted with calcium xylenesulphonate. The NOEC was 470 mg/L measured active substance.

The three short-term studies with potentially lower acute toxicity values included the 1995 OECD 202 Guideline supporting study with the test substance sodium xylenesulphonate that reported no immobility of daphnids at any concentration up to the highest concentration tested (100 mg/L); corresponding to an EC50 of >40.3 mg/L active substance. An acute invertebrate toxicity study for sodium cumenesulphonate is a static limit test conducted according to the OECD 202 guideline (1995). No mortality or immobility was observed and the 48-hr EC50 was reported as >100 mg/L (nominal concentration). A 1995 EU Method C.2 study of sodium toluenesulphonate conducted under GLP requirements followed a static test method with analytical confirmation of the test substance. The 48-hour EC50 was 54 mg/L active substance and the NOEC was 35 mg/L active substance. It is not apparent why this study has an order-of-magnitude lower toxicity value than the other four guideline studies. The study result is considered to be an outlier and is not taken into account in PNEC derivation.