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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The publication contains a significant level of details. Despite the study was not performed in accordance with a particular guideline, the tested species is recommended in the current guidances, and the measured parameters are considered in the American OPPTS guideline; revealing they are relevant indicators of toxicity. A restriction was nevertheless pointed as the test substance concentrations were not followed. However, it should be noticed that exposed organisms were transferred to freshly prepared substrate in the course of the experiment.
Principles of method if other than guideline:
The study does not follow any particular guideline. A long-term test was performed on the earthworm Eisenia foetida to assess the effect of a 42-day exposure to catechol on growth and survival. If reproduction is the primary parameter investigated in the long-term toxicity test of the OECD, both growth and survival are considered in the OPPTS guideline; indicating these parameters are relevant indicators of toxicity.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
not specified
Details on preparation and application of test substrate:
- Method of mixing into soil: Catechol was processed for assay by mixing 0.01, 0.1, 0.5 or 1 g into 100 g sludge which contained 11-15% solids. Assuming 13% solids in the sludge, the substances were thus tested at concentrations of about 0, 0.1, 1, 4, and 8% (w/w) dry weight, including controls. After 4 weeks of exposure, catechol-contaminated substrates were freshly prepared and worms were transferred there.
- Controls: yes, test substrate without catechol.
No further data. 
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: redworms, brandling worms, tiger worms or red wiggler worms
- Source: Stock cultures of E. fetida were maintained on horse manure or activated sludge. Hatchlings were obtained according to Hartenstein et al. (1981).
- Age at test initiation (mean and range, SD): No data, except that hatchlings were exposed.
- Weight at test initiation (mean and range, SD): 10 mg live, wt.

ACCLIMATION
No data.
Study type:
laboratory study
Substrate type:
other: activated sludge
Limit test:
no
Total exposure duration:
42 d
Test temperature:
24 +/- 1°C
pH:
No data
Moisture:
No data
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 20 x 100 mm Petri dish
- Amount of soil or substrate: About 30 g sludge (ca. 13% solids) with test substance or not (controls) were placed over a ca. 4 mm depth of silt loam.
- No. of organisms per container (treatment): 2
- No. of replicates per treatment group: 5
- No. of replicates per control: 5

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Preparation and characteristics of the substrate used: Humic acids were prepared from anaerobic and activated sludge digest. The pH of sludge, which contained about 2% solids w/w, was brought to pH 11 with 40% NaOH, centrifuged and the supernatant was collected by centrifugation, resuspended in alkali, reprecipitated and resuspended twice, dialyzed exhaustively against water and lyophilized. For exposure, 30 g of sludge contaminated or not with catechol, were placed over a ca. 4 mm depth of silt loam.

OTHER TEST CONDITIONS
- Photoperiod and light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
Growth was checked every 2 weeks. Growth achieved at 2 or 4 and 6 weeks was determined by rinsing the worms in distilled water, blotting and weighing. Mortality was determined by enumeration and said to be significant if 5 or more earthworms died.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: No regular spacing factor.
No further data.
Nominal and measured concentrations:
Assuming exactly 13% solids in the sludge, the catechol concentrations were: 0.1, 1, 4 and 8% (w/w) dry weight.
Based on gut load and transit time, E. foetida can be expected to ingest 5 mg dry activated sludge per 100 mg live wt/day. Assuming a 500 mg worm, the 50 mg ingesta would have provided 50, 500, 2000 and 4000 mg/kg/day, corresponding to 0.1, 1, 4 and 8% concentrations, respectively.
Duration:
42 d
Dose descriptor:
LOEC
Effect conc.:
ca. 4 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
42 d
Dose descriptor:
LOEC
Effect conc.:
ca. 2 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Duration:
42 d
Dose descriptor:
NOEC
Effect conc.:
ca. 2 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
42 d
Dose descriptor:
NOEC
Effect conc.:
ca. 500 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Details on results:
In the publication, the only reported toxicity results referred to the lowest concentrations which significantly reduced growth rate or caused death. These concentrations thus correspond to LOECs. By deduction, the NOECs are the concentrations immediately lower than that causing the first significant effects.
Reported statistics and error estimates:
Weight at 6 weeks was evaluated by analysis of variance. Significant differences were determined by the Neuman-Keul test.
Validity criteria fulfilled:
not specified
Conclusions:
Based on mortality of Eisenia foetida, catechol presents 42d-NOEC and -LOEC of 2000 and 4000 mg/kg dw. Based on growth, catechol presents 42d-NOEC and -LOEC of 500 and 2000 mg/kg dw.
Executive summary:

Hartenstein (1982) investigated the chronic effects of catechol on Eisenia foetida. No particular guideline was followed, but this worm species is that recommended in the current guidances, and the measured parameters are considered in the OPPTS guideline; revealing they are relevant indicators of toxicity. Hatchlings were exposed for 42 days to 50, 500, 2000 and 4000 mg/kg dw of catechol. Mortality and growth were assessed. The first significant effects were observed at 2000 and 4000 mg/kg dw for growth and mortality, respectively. These values were thus retained as 42d-LOECs. By deduction, the 42d-NOECs based on growth and mortality were 500 and 2000 mg/kg dw, respectively.

Description of key information

Based on Eisenia foetida survival: 42d-NOEC = 2000 mg/kg dw, 42d-LOEC = 4000 mg/kg dw.
Based on Eisenia foetida growth: 42d-NOEC = 500 mg/kg dw, 42d-LOEC = 2000 mg/kg dw.

Key value for chemical safety assessment

Additional information

Only one reliable study is available (Hartenstein, 1982). Despite it did not follow any guideline, it was scored as a reliability 2 and flagged as a key study. Indeed, it was fully described, the test species is that recommended in the current guidances and the measured parameters are relevant indicators of toxicity. Eisenia foetida hatchlings were exposed for 42 days to catechol concentrations of 50, 500, 2000 and 4000 mg/kg dw. Based on mortality, catechol presented 42d-NOEC and -LOEC of 2000 and 4000 mg/kg dw. Based on growth, catechol presented 42d-NOEC and -LOEC of 500 and 2000 mg/kg dw.

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