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Long-term toxicity to aquatic invertebrates

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Reference
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1976-04 to 1977-02
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented, equivalent to guideline
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Deviations:
no
GLP compliance:
no
Remarks:
Study pre-dates GLP
Analytical monitoring:
yes
Details on sampling:
- Concentrations: all concentrations
- Sampling method: Samples were taken from test vessels on day 0, and every 3-5 days through out the 21-day test.
- Sample storage conditions before analysis: Preserved with 1% formaldehyde and stored at 5 C until analysis.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Direct dilution of the appropriate amount of test substance into blended well water
- Controls: Blended well water
- Evidence of undissolved material: no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Strain/clone: N/A
- Source: In-house culture
- Age of parental stock: not specified
- Age of test organisms: <12 h old at beginning of test
- Feeding during test: yes
- Food type: ground trout chow/alfalfa mixture, 1000 mg/L
- Amount: 5 mg/L
- Frequency: Each diluter cycle

ACCLIMATION
- Acclimation period: Not specified
- Acclimation conditions (same as test or not): N/A
- Type and amount of food: N/A
- Feeding frequency: N/A
- Health during acclimation (any mortality observed): N/A

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Young were manually siphoned from existing culture units.
Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Hardness:
120 +/- 18 mg/L CaCO3
Test temperature:
21 +/- 1 C
pH:
7.5 +/- 0.2 SU
Dissolved oxygen:
8.9 +/- 0.4 mg/L
Salinity:
N/A
Nominal and measured concentrations:
The nominal test concentrations were not specified in the study report. Mean Measured concentrations were 0, 0.32, 0.59, 1.18, 2.52, and 4.85 mg/L C11.8 LAS (active ingredient).
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: open
- Material: 1 liter glass beakers, 1 L test solution
- Aeration: N/A (test was flow-thru)
- Type of flow-through: Mount and Brungs proportional diluter, with modifications
- Renewal rate of test solution: 125 ml per 20 min cycle, or one chamber volume every 2.5 hr.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 5 daphnids/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Blended well water (a mixture of well water and deionized water)
- Total organic carbon: N/A
- Particulate matter: N/A
- Metals: N/A
- Pesticides: N/A
- Chlorine: N/A
- Alkalinity: N/A
- Ca/mg ratio: N/A
- Conductivity: N/A
- Salinity: N/A
- Culture medium different from test medium: No
- Intervals of water quality measurement: Daily

OTHER TEST CONDITIONS
- Adjustment of pH: N/A
- Photoperiod: N/A
- Light intensity: N/A

EFFECT PARAMETERS MEASURED: Mortality, 24 hr, 96 hr, 7 days, then daily to end of test. Reproduction, daily beginning day 7 or 8 to end of test.

RANGE-FINDING STUDY: no
Reference substance (positive control):
no
Key result
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1.18 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
other: Parent (F0) Survival and reproduction (Total # young in 21 days; and Mean Brood Size)
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
1.5 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
other: Total young production
Remarks on result:
other: 95% CL 0.75-3.33 mg/L
Duration:
21 d
Dose descriptor:
LC50
Effect conc.:
1.67 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Remarks on result:
other: 95% CL 1.28-2.18 mg/L
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
2.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
other: Average brood size
Remarks on result:
other: 95% CL 1.62-3.55 mg/L
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
2.31 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
other: Percentage of days reproduction occurred
Remarks on result:
other: 95% CL 0.30-4.18 mg/L
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
3.94 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Remarks on result:
other: 95% CL 2.87-6.83 mg/L
Details on results:
- Mortality of parent animals: Controls, 10%
- No. of offspring produced per Control: 39
- Body length and weight of parent animals: N/A
- Type and number of morphological abnormalities: N/A
- Type and number of behavioural abnormalities: N/A
- Number of males and females (parental): N/A
- Time to first brood release or time to hatch- 7 or 8 days
- Egg development time: N/A
- Brood size: Control, 8.0 (mean)
- Time to sexual maturity: N/A
- Type and magnitude of biochemical changes: N/A
- Other biological observations: N/A
- Effect concentrations exceeding solubility of substance in test medium: no
Reported statistics and error estimates:
All results were calculated with a computerized probit analysis program after Finney (1964, 1971). Survival data for 96 hr and 21 days was used to calculate LC50 values and confidence limits. All results were calculated based on mean measured concentrations of test material.

Chronic Toxicity of C11.8 LAS to Daphnia magna (study # 20710)

Mean Measured Test Conc (mg/L)

% Survival

Total Young Produced

Mean Brood Size

% of Days that Reproduction Occurred

0

90

786

8.0

82

0.32

85

1445

11.7

96

0.59

85

1131

9.7

90

1.18

75

1036

10.7

86

2.52

40

477

7.9

71

4.85

0

0

0

0

N=20 organisms at beginning of test (4 replicates of 5 organisms each).

LAS = linear alkylbenzene sulfonate.

Validity criteria fulfilled:
yes
Conclusions:
The 21 day NOEC of C11.8 LAS to Daphnia magna was 1.18 mg/L, based on survival and reproduction. The 21 day LC50 was 1.67 mg/L. Results are based on the mean measured concentration of the active ingredient.
Executive summary:

The long-term toxicity of C11.8 LAS (linear alkylbenzene sulfonate)) was evaluated in a 21 day survival and reproduction test with Daphnia magna, following the OECD 211 guideline. Four replicates per concentration, 5 organisms per replicate, were tested in a flow-through system (a modified Mount and Brungs proportional diluter). Mean measured concentrations were: Control, 0.32, 0.59, 1.18, 2.52, and 4.85 mg/L active ingredient (C11.8 LAS).

 

Survival was monitored at 24 hr, 96 hr, 7 days and daily thereafter. Reproduction was monitored beginning with the production of the first brood on day 7 or 8, and daily thereafter. LC50s and EC50s were calculated by probit analysis. Results are based on the mean measured concentration of the active ingredient.

 

The 21-day NOEC was 1.18 mg/L, based on both survival and reproduction. The 21-day LC50 was 1.67 mg/L (95% CL 1.28 -2.18 mg/L). The 21-day EC50s, based on total young production, average brood size, and % days reproduction occurred, were 1.50, 2.30, and 2.31 mg/L, respectively.


Description of key information

LAS provides suitable read across for LAB Sulfonic Acids as both form the identical chemical species in aqueous solutions at environmental pH’s, namely, the LAS ion (C10-13 linear alkyl benzene-SO3-).

A series of studies are used to characterize the long-term toxicity of LAS to aquatic invertebrates. In the first study (Maki 1977; van de Plassche et al 1999), the toxicity of C11.8LAS was evaluated in a 21-day survival and reproduction test with Daphnia magna. Four replicates per concentration, five organisms per replicate, were tested in a flow-through system. Mean measured concentrations were 0.32, 0.59, 1.18, 2.52, and 4.85 mg/L C11.8LAS as active ingredient. Survival was monitored at 24-hr, 96-hr, 7 days and daily thereafter. Reproduction was monitored beginning with the production of the first brood on day 7 or 8, and daily thereafter. Results, based on the mean measured concentration of the active ingredient, indicate that the 21-day NOEC was 1.18 mg/L. The 21 day LC50 was 1.67 mg/L, while the EC50s, based on total young production, average brood size, and percent days reproduction occurred, were 1.50, 2.30, and 2.31 mg/L, respectively. These results were then normalized to a C11.6LAS according to the methods of van de Plassche et al. (1999), and the final NOEC value is 1.41 mg/L.

In another study (Taylor 1984; van de Plassche et al 1999), a 7 day chronic toxicity test on C11.8LAS was conducted with Ceriodaphnia sp. under semi-static conditions.Ceriodaphnia were fed either a yeast diet, or an algae/trout chow diet. The test medium was renewed three times in the seven days. Nominal test concentrations were 0, 0.5, 1, 2, 3.5, 5 and 7 mg/L of active ingredient. The resultant 7 day LC50 values were 5-7 mg/L for both diets. The no effect concentrations differed between diets. The 7 day NOEC for the yeast diet was 0.5 mg/L (based on reproduction) while the 7 day NOEC for the algae/trout chow diet was 5 mg/L (based on mortality and reproduction). When normalized to a C11.6LAS, the lowest NOEC is 0.59 mg/L.

In the third study (Maki 1978, 1981; van de Plassche et al 1999), effects on the midge were examined. Groups of P. parthenogenica were exposed for 28 days to concentrations of 0.5, 1.0, 2.0, or 4.0 mg/L (nominal) of LAS. The LOEC was 4 mg/L based on survival and reproduction, and the NOEC was 2.0 mg/L. When normalized to C11.6LAS, the NOEC value becomes 2.8 mg/L.

The chronic toxicity of C12.3LAS was evaluated in a 2 day whole life cycle bioassay on the rotifer, Brachionus calyciflorus (Procter & Gamble 1996; van de Plassche et al 1999). Six newly hatched rotifers (<3 hours old) were placed in each replicate beaker, and exposed to C12.3LAS for 48 hours. Results were based on the total number of live, swimming organisms (both adults and offspring) and measured concentrations. The resultant EC10 value was 1.18 mg a.i./L, the EC20 was 1.4 mg a.i./L, and the EC50 was 2.0 mg a.i./L. When normalized to a C11.6LAS, the EC10 value becomes 1.69 mg/L.

Finally, the chronic toxicity of C12LAS was determined in a 32 day test (Versteeg 2001; Versteeg and Rawlins 2003; van de Plassche et al 1999) with three aquatic invertebrates (Corbicula, Elimia, Hyalella). The invertebrates were caged in the tail pools of an environmental stream mesocosm study of C12LAS. Toxicity was based on water concentrations at which adverse effects were observed. Results were also calculated based on the tissue concentrations at which adverse effects were observed. All invertebrates were exposed to nominal concentrations of 0, 0.15, 0.30, 1.0, and 3.0 mg a.i./L. As mean measured concentrations were 84-99% of nominal, results are based on measured concentrations. On days 0, 8, 16, and 32, the invertebrates were examined for growth and survival. The results can be summarized as follows (all normalized to C11.6): For Corbicula, the 32 day EC20 was 0.39 mg/L based on growth (length), for Elimina, the 32 day NOEC was 4.15 mg/L based on survival and for Hyalella the 24 day EC20 was 1.36 mg/L based on survival.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
0.268 mg/L

Additional information