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Long-term toxicity to fish

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Endpoint:
fish early-life stage toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
other: Benoit et al. 1982. A fathead minnow, Pimephales promelas, early life stage toxicity test method evaluation and exposure to four organic chemicals. Environ. Pollute 28: 189-297.
Qualifier:
according to
Guideline:
other: U.S. EPA. 1982. Wildlife aquatic organism data requirements. U.S. Government Printing Office, Washington, D.C. Federal Register 47: 53212.
GLP compliance:
no
Analytical monitoring:
yes
Details on sampling:
- Sampling: weakly
Vehicle:
not specified
Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: fathead minnow embryos and larvae
Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 d
Nominal and measured concentrations:
control, solvent control, 0.75, 1.5, 3.2, 7.4, and 15.0 (mean measured)
Details on test conditions:
TEST SYSTEM
- Type of flow-through (e.g. peristaltic or proportional diluter): Mount and Brungs (1967) type proportional diluters

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): hatching of embryos, survival and growth of larvae
Duration:
30 d
Dose descriptor:
NOEC
Effect conc.:
1.5 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
30 d
Dose descriptor:
NOEC
Effect conc.:
3.2 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality

Table 1: The effects on the embryos and larvae

Measured Concentration (mg/L)*

Hatch (%)*

30 days post hatch

Survival (%)*

Length (mm)*

Weight (mg)*

15(1)

56(31)**

0(0)**

-

-

7.4(0.9)

66(20)**

12(5)**

14(1)**

20(2)**

3.2(0.3)

84(6)

69(1)

19(2)**

53(3)**

1.5(0.3)

68(12)

62(2)

21(3)

78(8)

0.75(0.2)

98(1)

58(25)

22(2)

90(22)

Solvent Control

96(2)

86(2)

21(2)

80(6)

Control

94(6)

93(10)

21(2)

70(1)

* Mean (standard deviation)

** Significantly (p = 0.05) different from controls

Exposure to 7.4 and 15 mg/L 2,4-xylenol significantly reduced the hatching of fathead minnow embryos. No fathead minnow larvae survived exposure to 15 mg/L and survival of larvae was significantly reduced at 7.4 mg/L. Larvae survival was not affected at concentrations as high as 3.2 mg/L. Larvae growth was significantly reduced at concentrations of 3.2 and 7.4 mg/L , but was not affected at 0.75 and 1.5 mg/L.

Validity criteria fulfilled:
not specified
Endpoint:
fish early-life stage toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 210 (Fish, Early-Life Stage Toxicity Test)
Principles of method if other than guideline:
Early life stage test
GLP compliance:
no
Analytical monitoring:
not specified
Test organisms (species):
Pimephales promelas
Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
32 d
Hardness:
soft water from lake Superior
Test temperature:
25 ± 0.2 °C
Dissolved oxygen:
≥ 6.1 mg/L
Details on test conditions:
- Fluorescent lights provided 16h light per day
- Water chemistry data was recorded at the Environmental Research  Laboratory, Duluth, MN
- Fish were fed newly hatched brine shrimp ad libitum twice per day so that moderate accumulation occured.
Duration:
32 d
Dose descriptor:
NOEC
Effect conc.:
1.35 mg/L
Nominal / measured:
not specified
Conc. based on:
test mat.
Basis for effect:
larval development
Duration:
32 d
Dose descriptor:
LOEC
Effect conc.:
2.57 mg/L
Nominal / measured:
not specified
Conc. based on:
test mat.
Basis for effect:
larval development

NOEC for macromolecular content (nucleic acid, protein) was 2.57 mg/L (LOEC 4.20 mg/L). NOEC for growth was >4.2 mg/L

Validity criteria fulfilled:
not specified
Executive summary:

The chronic toxicity of p-cresol to fish was tested with Pimephales promelas in an Early-Life Stage Toxicity Test equivalent to OECD Guideline 210. The 32d NOEC is 1.35 mg/L.

Description of key information

Based on all available information and following an analogue read-across and worst case approach the freshwater NOEC (32d) of 1.35 mg/L determined for Pimephales promelas (Barron & Adelman, 1984) for p-cresol represent the most sensitive effect value for chronic toxicity to fish for Tar acids, Xylenol fraction (CAS 84989-06-0) and is considered as key value for the chemical safety assessment.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater fish:
1.35 mg/L

Additional information

Data on chronic toxicity to fish are available for two constituents of Tar acids, Xylenol fraction (CAS 84989-06-0) (p-cresol and 2,4 -xylenol). These data are used to determine the long-term hazard on fish by applying an analogue read-across approach. The studies were conducted with Pimephales promelas as test species. The resulting NOEC values of the two studies are in the same range with 1.35 mg/L for p-cresol (Barron & Adelman, 1984) and 1.5 mg/L for 2,4-xylenol (Le Blanc, 1984). The lower NOEC value of 1.35 mg/L for p-cresol was considered for PNEC derivation and risk assessment and for deriving environmental classification. For details on the read-across approach please refer to the analogue justification provided in IUCLID section 13.

Chronic effect values determined in the available studies are listed in the table below:

Source

*

Species

p-cresol

m-cresol

o-cresol

Barron & Adelman, 1984

f

Pimephales promelas

NOEC (32d) = 1.35 mg/L

-

-

 

2,3-xylenol

2,4-xylenol

2,5-xylenol

Le Blanc, 1984

f

Pimephales promelas

-

NOEC (30d) = 1.5 mg/L

-

* f = freshwater