Pitch, coal tar, high-temp., < 1% 4- to 5-membered condensed ring aromatic hydrocarbons

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

open test conditions

Principles of method if other than guideline:

Preparation of the water-accommodated fraction (WAF) as part of a toxicity study.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

Original name: Pitch, coal tar, high-temp., heat-treated [EC no. 310-162-7; CAS no. 121575-60-8] (CTPhtht)

Water solubility:

< 0.2 other: mg DOC/L

Temp.:

20 °C

pH:

>= 7.7 - <= 8.2

Remarks on result:

other: estimated value from TOC measurements

Details on results:

Solubility data relate to loadings of 100 - 1000 mg pitch/L (see Remarks on results below).

Water solubility (as water-accommodated fraction) of CARBORES at 20 °C

in test medium (daphnia) at various loadings:

Note: Pitch-related values are in the range of background values and

hence are not precisely quantifiable by the method applied.

A. Main test

	Loading [mg/L]
	Control	1000
	WAF [mg TOC/L]
24 h (stirring)	0.9	0.5

Note: Values represent TOC including background.

B. Pre-test

	Loading [mg/L]
	Control	100	1000
	WAF [mg TOC/L]
24 h (stirring)	0.6	0.5	0.7

Note: Values represent TOC including background.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Principles of method if other than guideline:

As a summation parameter, TOC was measured rather than single PAHs.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

- Physical state: solid (here: applied as fine-granular powder < 180 µm)
- Density: 1.30 – 1.35 g/cm³ (20°C) (DIN 51 757)
- Stability under test conditions: WSF (water-soluble fraction): limited
- Storage condition of test material: room temperature, exclusion of light

Key result

Water solubility:

0.242 mg/L

Conc. based on:

other: dissolved organic carbon (DOC)

Loading of aqueous phase:

1 000 mg/L

Temp.:

20 °C

pH:

6.8

Remarks on result:

other: average over 3 time intervals (24, 48, and 72 h) measured in replicate samples

Water solubility:

0.215 mg/L

Conc. based on:

other: dissolved organic carbon (DOC)

Loading of aqueous phase:

100 mg/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

6.7

Remarks on result:

other: average at 72 h (replicate samples)

Solubility Results for Pitch, coal tar, high temp(coal-tar pitch)

(Mean values of two replicates per time interval) (data taken from Table 4 of the report, modified)

Sample		Carbon content [mg/L]
Dilution water^1)		0.732	Mean	Mean over time (24, 48, 72 h)^4)	Mean over time (48, 72 h)^4)	Deviation (48, 72 h) [%]
1000 mg/L	No. 1 (24 h)	0.320	0.289^2)	0.242
	No. 2 (24 h)	0.258
	No. 1 (48 h)	0.988	0.204^3)		0.218	14.5
	No. 2 (48 h)	0.883
	No. 1 (72 h)	0.930	0.233^3)
	No. 2 (72 h)	1.000
100 mg/L	No. 1 (72 h)	0.186	0.215^2)
	No. 2 (72 h)	0.243

1) Dilution water for samples 48, 72 h at 1000 mg/L loading (measured 2010-11-15)

2) Mean values of replicates, dilution water carbon content not subtracted as dilution water carbon content

was 0 mg/L (measured 2010-11-12)

3) Mean values of replicates, dilution water carbon content subtracted (measured 2010-11-15)

4) The time average over 24,48, and 72 h was calculated, thus deviating from the study report in which only the average over 48 and 72 h has been quoted.

Reference 3

Endpoint:

water solubility

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

ANALOGUE APPROACH JUSTIFICATION
Coal-tar pitch, high temp. [CAS no. 65996-93-2] is the precursor of CTPhtht and used as analogue: similar structure and phys-chem. properties like the target substance, Pitch, coal tar, high-temp., < 1% 4- to 5-membered condensed ring aromatic hydrocarbons [EC no. 701-305-8] (CTPhtht).

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Read-across to preceding entry:
Source test material: pitch, coal tar (CTP)
Reference: NOACK 2011, water solubility

Specific details on test material used for the study:

Original name: Pitch, coal tar, high-temp., heat-treated [EC no. 310-162-7; CAS no. 121575-60-8] (CTPhtht)

Key result

Water solubility:

0.242 mg/L

Conc. based on:

other: Dissolved Organic Carbon (DOC)

Loading of aqueous phase:

1 000 mg/L

Temp.:

22 °C

pH:

6.8

Remarks on result:

other: average over 3 time intervals (24, 48, and 72 h) measured in replicate samples

Key result

Water solubility:

0.215 mg/L

Conc. based on:

other: Dissolved Organic Carbon (DOC)

Loading of aqueous phase:

100 mg/L

Incubation duration:

72 h

Temp.:

22 °C

pH:

6.7

Remarks on result:

other: 72 h (replicate)

Description of key information

The water solubility of  Pitch, coal tar, high-temp., < 1% 4- to 5-membered condensed ring aromatic hydrocarbons [EC no. 701-305-8] (CTPhtht) at 20 °C is estimated to be < 0.2 mg DOC/L at a loading of 1000 mg/L. 

Key value for chemical safety assessment

Water solubility:

0.002 mg/L

at the temperature of:

20 °C

Additional information

In an acute daphnia study with Pitch, coal tar, high-temp., < 1% 4- to 5-membered condensed ring aromatic hydrocarbons [EC no. 701-305-8] (CTPhtht), the measured TOC values at a loading of 1000 mg/L did not significantly differ from those of the control values. The relevant WAF is estimated to be < 0.2 mg/L (STZ 2007).

For coal-tar pitch, the structure analogous precursor compound, the mean TOC of the water-soluble fraction (WAF) was 0.24 mg/L at a loading of 1000 mg pitch/L. at 20 °C. A total of 0.8 to 1.4 µg/L was found in the WAF of a loading of 100 mg/L at 21 °C, related to the 16 EPA PAHs. It is conclusive to assume that CTPhtht [EC no. 701-305-8] will have a lower water solubility than coal-tar pitch, the precursor material [CAS No. 65996-93-2].

The solubility of benzo[a]pyrene (BaP) is adopted as representative parameter for single constituents that may be released and bioavailable.