Tar acids, xylenol fraction

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Preliminary guideline proposal of the German Umweltbundesamt, state 1984-01-01

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

IRCHA strain - Age: 24 h

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

2.5 mmol/l Ca + Mg
synthetic fresh water

Test temperature:

25 +/- 1 °C

pH:

8.0 +/- 0.2
pH values were measured during the test in two tests-vessels per concentration level. The detected variation of the parameter had
no negative influence on the organisms.

Dissolved oxygen:

oxygen-concentrations were measured during the test in two tests-vessels per concentration level. The detected variation of the parameter had
no negative influence on the organisms.

Salinity:

Na/K ratio: 10:1

Details on test conditions:

- Tested concentration range: 0.003-10 mg/L
Determination of NOEC for reproduction rate, parent mortality, and the time of the first appearance of offspring
- Number of replicates: 4
- individuals per replicate: 20

Reference substance (positive control):

yes

Remarks:

chromate

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

the most sensitve parameter (of parent animal mortality, reporduction rate, and appearance of first offspring) was used for NOEC determination

- Only the nominal value for the most sensitive parameter is given. However, no losses were reported to be greater than 20%.
- Tested concentration range: 0.003-10 mg/L

Validity criteria fulfilled:

not applicable

Executive summary:

The long-term toxicity of p-cresol to aquatic invertebrates was determined by a test according to the preliminary guideline proposal of the German Umweltbundesamt from1984. The 21d-NOEC is 1 mg/L.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Static bioassay

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

other aquatic worm: Dugesia tigrina (Planaria)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

80 d

Test temperature:

20 °C

Duration:

80 d

Dose descriptor:

EC10

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality, regeneration, and growth

LC50 = 11.08 mg/l after 10 days
LC10 = 2.0 mg/l after 80 days (4 generations)
LC20 = 4.0 mg/l after 80 days (4 generations)

Validity criteria fulfilled:

not applicable

Executive summary:

In a non-guideline study with a 4 generations of the planarian Dugesia tigrina, an 80 d-EC10 of 2 mg/L was measured.

Reference 3

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

static bioassay

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Dilution series of a stock solution with moderate hard synthetic fresh water and mixed with appropriate volume of algae suspension; the suspension was mixed gently on a magnetic stirrer( approx. 120 rpm)for max. 30 min; 12 mL were used per test vessel;
- Controls: yes

Test organisms (species):

other: Brachionus calyciflorus

Details on test organisms:

TEST ORGANISM
- Common name: Rotifer cyst
- Strain/clone: Brachionus calyciflorus Pallas
- Justification for species other than prescribed by test guideline:
- Source: originally collected in Gainesville, Florida,USA
- Age of parental stock (mean and range, SD): 15 - 16 h
Feeding during test
- Food type: Green algae Nannochloris oculata
- Amount: 12 mL to each test tuve of stock solution: 3.0 x 10 E+06 cells/mL; an appropriate amount was added to the dilution water and an appropriate amount of test item (toxicant)
- Frequency: once

ACCLIMATION
- Acclimation period: 15 - 16h (time until hatching)

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Test animals were obtained by hatching rotifer cysts after 15 - 16 h. Hatching was initiated by placing about 40 ml of dilution water into a petri dish along with one cyst vial (approximately 3,000 cysts). The hatching dish was incubated at 25°C in light of 2,000 to 4,000 lux for 15 to 16 h. Hatching started after about 16 h, and within 2 h rotifers were transfer to test tubes.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

25 °C

pH:

7.5

Nominal and measured concentrations:

control treatment and five test concentrations

Details on test conditions:

TEST SYSTEM
Test vessel:
- Type: closed (capped)
- Material, size, headspace, fill volume: 16 x 150 mm disposable glass; 12 mL test volume;
- No. of organisms per vessel: 6 females
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 5

- Biomass loading rate: 6 females in 12 mL

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water consisted of 96 mg NaHCO, 60 mg CaSO4.2H2O, 60 mg MgS04.7H20, and 4 mg KCI in 1L of deionized water, adjusted to pH 7.5 with 10 M KOH or HCI, deionized water from Sybron-Barnstead (Dubuque, IA) Nanopure II@ system.
- Culture medium different from test medium: not different

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: darkness
- Light intensity: darkness
- Others: placed on a rotator revolving at 10 - 15 rph

EFFECT PARAMETERS MEASURED: Reproduction rate: number of animals per tubes were counted

RANGE-FINDING STUDY no range-finding test was performed

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: reproduction (total number of offspring per single female within a 48 h test period)

Validity criteria fulfilled:

not applicable

Description of key information

Based on all available information (weight-of-evidence and following an analogue read-across and worst case approach the freshwater NOEC (21d) of 1.0 mg/L determined for Daphnia magna (Kühn et al., 1988; Kühn, 1989) for p-cresol represents the most sensitive effect value for chronic toxicity to aquatic invertebrates 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

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1 mg/L

Additional information

Data on the chronic toxicity to aquatic invertebrates are available for constituents of Tar acids, Xylenol fraction (CAS 84989-06-0), i.e. p-cresol and 2,4-xylenol. These data are used to determine the hazard of Tar acids, Xylenol fraction (CAS 84989-06-0) by applying a weight of evidence and an analogue read-across approach. The studies were conducted with different species of freshwater invertebrates. A worst-case scenario is followed, i.e. for classification and assessment purposes the most sensitive values are considered. Although only data for p-cresol and 2,4-xylenol are available it is emphasized here, that there is numerous data available for several different constituents for acute and chronic toxicity to fish and acute toxicity to aquatic invertebrates. These data exemplify that effect values are in general in the same order of magnitude and effect values for p-cresol in particular are among the lowest. Therefore, data presented here for chronic aquatic toxicity to invertebrates are considered to be representative for Tar acids, Xylenol fraction (CAS 84989-06-0). For details on the read-across approach please refer to the analogue justification provided in IUCLID section 13.

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

Source	*	Species	p-cresol	2,4-xylenol
Solski & Piontek, 1987	f	Dugesia tigrina	EC10 (80d) = 2.0 mg/L	-	-
Kuehn et al., 1988-1989	f	Daphnia magna	NOEC (21d) = 1.0 mg/L	-	-
Snell & Moffat, 1992	f	Brachionus calyciflorus	-	NOEC (24h) = 2.0 mg/L	-

* f = freshwater

From the table above it can be seen that available data demonstrate effect values for chronic toxicity to aquatic invertebrates in a close range from 1.0 to 2.0 mg/L. The most sensitive value for freshwater (Daphnia magna) was determined in the study by Kühn et al. (1988) and Kühn (1989) with a NOEC (21d) of 1.0 mg/L for p-cresol. This value is considered for PNEC derivation and risk assessment and for deriving environmental classification.