Activated Carbon - Low Density Skeleton

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

17/10/2012 - 03/11/2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study according to international guideline (OECD guideline 105) under GLP. No deviations significantly affecting study reliability were reported. The study was assigned a Klimisch 2 rating due to the read-across purpose, in accordance with the ECHA Practical guide #6 on the reporting of read-across in IUCLID.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline".

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline".

Principles of method if other than guideline:

Deviation No. 1 (31 December 2012).
The Study Plan stated that four column elution systems will be rinsed with water for one week, prior to draining and loading the test item in the relevant columns, etc. This was to allow for two sample columns, at flow rates of ~ 25 mL/hr and ~ 12.5 mL/hr, as well as two blank columns (one for each flow rate). However, due to apparatus issues, it was decided to split the testing and perform the ~ 25 mL/hr tests first, and then perform the ~ 12.5 mL/hr testing using the same systems as earlier but this time with the flow rates halved. Additionally, the Sponsor/Study Monitor indicated that the test item had to be rinsed with water in the columns for (at least) one week, to remove any water-soluble impurities (prior to draining, re-filling, re-starting the flow, and sampling, etc.). Thus, overall, the column elution systems and the test item were rinsed for (at least) one week, prior to taking any of the time point samples. The impact of these changes on the study was considered to be negligible.

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

< 1 mg/L

Temp.:

20 °C

pH:

7

Remarks on result:

other: Stanadard error of temperature is +/- 0.5ºC

Details on results:

The result is below the LoQ of 1.0 mg/L.

High flow results

Sample number	Total Contact Time (hours)	TOC concentration (g/L)		Solution pH
		Sample	Sample Blank
1	190	0.6591	0.6403	7.1
2	192	0.9399	1.081	7.1
3	194	0.7273	0.6736	7.1
4	196	0.7863	1.088	7.2
5	213	0.581	0.7318	7.1
6	216	1.126	0.865	7.1
7	218	0.5727	1.042	7
8	220	0.5416	0.6093	7

Low flow results

Sample number	Total Contact Time (hours)	TOC concentration (g/L)		Solution pH
		Sample	Sample Blank
1	334	0.7742	1.056	7
2	338	0.7676	0.7799	7.1
3	342	0.5584	0.4571	6.8
4	358	0.3988	0.3778	7
5	362	0.7131	0.8601	7.2
6	366	0.2192	0.345	7
7	380	0.6851	0.5127	7
8	384	0.7103	0.5261	7.1

Overall results

Flow rate (mL/h)	Overall TOC Concentration (mg/L)
25.5	< 1.0
12.5	< 1.0
Overall	< 1.0

Conclusions:

Interpretation of results (migrated information): other: < limit of quantification of 1 mg/L
The water solubility of Activated Carbon (Sugar Based) - Preparation (1) is < 1 mg/L at 20ºC and pH 7.

Executive summary:

The water solubility of Activated Carbon (Sugar Based) - Preparation (1) was determined according to OECD guideline 105 under GLP using the column elution method. The limit of quantitation (LOQ) of the TOC analysis has been determined to be 1.0 mg/L TOC. Subsequently, all sample results after correction for sample blank have been assessed as being < LOQ, i.e. < 1.0 mg/L TOC. Thus, the water solubility was found to be < 1 mg/L at 20ºC and pH 7.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

17/10/2012 - 06/11/2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study according to international guideline (OECD guideline 105) under GLP. No deviations significantly affecting study reliability were reported. The study was assigned a Klimisch 2 rating due to the read-across purpose, in accordance with the ECHA Practical guide #6 on the reporting of read-across in IUCLID.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline".

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline".

Principles of method if other than guideline:

Deviation No. 1 (31 December 2012).
The Study Plan stated that four column elution systems will be rinsed with water for one week, prior to draining and loading the test item in the relevant columns, etc. This was to allow for two sample columns, at flow rates of ~ 25 mL/hr and ~ 12.5 mL/hr, as well as two blank columns (one for each flow rate). However, due to apparatus issues, it was decided to split the testing and perform the ~ 25 mL/hr tests first, and then perform the ~ 12.5 mL/hr testing using the same systems as earlier but this time with the flow rates halved. Additionally, the Sponsor/Study Monitor indicated that the test item had to be rinsed with water in the columns for (at least) one week, to remove any water-soluble impurities (prior to draining, re-filling, re-starting the flow, and sampling, etc.). Thus, overall, the column elution systems and the test item were rinsed for (at least) one week, prior to taking any of the time point samples. The impact of these changes on the study was considered to be negligible.

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

< 1 mg/L

Temp.:

20 °C

pH:

7

Remarks on result:

other: Standard error of temperature is +/- 0.5ºC

Details on results:

The result is below the LoQ of 1.0 mg/L.

High flow results (26.0 mL/h)

Sample number	Total Contact Time (hours)	TOC concentration (g/L)		Solution pH
		Sample	Sample Blank
1	190	0.8175	0.8331	6.9
2	192	0.5891	0.9692	7.2
3	194	0.5956	0.8553	7.0
4	196	0.7373	0.6166	7.1
5	213	0.7455	0.6245	7.1
6	216	0.7892	1.038	7.0
7	218	0.5553	0.6763	7.0
8	220	0.3876	0.7204	7.0

Low flow results (12.5 mL/h)

Sample number	Total Contact Time (hours)	TOC concentration (g/L)		Solution pH
		Sample	Sample Blank
1	334	0.9695	0.933	7.1
2	338	0.9818	1.048	7.0
3	342	0.5541	0.7301	7.1
4	358	0.6329	0.5614	7.0
5	362	0.9734	0.7608	7.0
6	366	0.4918	0.4864	7.0
7	380	0.4611	0.4957	7.0
8	384	0.5173	0.422	7.1

Overall results

Flow rate (mL/h)	Overall TOC Concentration (mg/L)
26.0	< 1.0
12.5	< 1.0
Overall	< 1.0

Conclusions:

Interpretation of results (migrated information): other: < 1 mg/L which is the limit of quantification
The water solubility of Activated Carbon (Sugar Based) - Preparation (2) is < 1 mg/L at 20ºC and pH 7.

Executive summary:

The water solubility of Activated Carbon (Sugar Based) - Preparation (2) was determined according to OECD guideline 105 under GLP using the column elution method. The limit of quantitation (LOQ) of the TOC analysis has been determined to be 1.0 mg/L TOC. Subsequently, all sample results after correction for sample blank have been assessed as being < LOQ, i.e. < 1.0 mg/L TOC. Thus, the water solubility was found to be < 1 mg/L at 20ºC and pH 7.

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10/03/2010 - 22/06/2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

performed under GLP

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

< 0.1 mg/L

Temp.:

20 °C

pH:

6.8

Details on results:

During the pre-test the water solubility of the test item at about 23 °C was estimated to be 3.9 mg/L by a simplified flask test. Therefore, the column elution method was used for the performance of the main test.

During the main test six samples have been analyzed during the first run (0.42 mL/min) and six samples during the second run (0.21 mL/min), each with a sampling interval of at least ten bed volumes. Total elution time was 190.25 hours. The quantification of the test item content was performed by TOC measurement. The water solubility of Chemically Activated Carbon at 20 °C was determined to be 2.69 mg/. The TOC content of a blank solution treated in exactly the same way like the test item solution has been determined to be 3.57 mg/L.

The values for sample No. 1 and 2 in Table 1 and 2 respectively are exceptionally high. As the analytical method is very sensible to possible contaminations this might be the result of such a contamination. The two high values are also the reason that the SD is relatively high in case of the higher flow.

The reason for the higher TOC valve of the blank solution might be as follows: The whole apparatus (pump, tubes etc.) has a lot of possible sources of carbon contamination. The Chemically Activated Carbon absorbs such contaminations up to a certain amount and therefore
the samples with Chemically Activated Carbon show a lower TOC than the blank sample.

The TOC content of the test item solution is lower than the TOC content of the blank solution. Thus it can be concluded that no test item is soluble in water.

For detailed results, see attached file "results.doc".

Conclusions:

Interpretation of results (migrated information): insoluble (< 0.1 mg/L)
Chemically activated carbon is insoluble in water.

Executive summary:

The water solubility of chemically activated carbon was determined according to OECD guideline 105 under GLP using the column elution method. It was found that chemically activated carbon is insoluble in water at pH 6.8 and a temperature of 20 degrees Celsius.

Description of key information

The substance is not soluble in water.

Additional information

In a key study, the water solubility of Activated Carbon - Low Density Carbon was determined according to OECD guideline 105 under GLP using the column elution method. It was found that Activated Carbon - Low Density Carbon is insoluble in water at pH 6.8 and a temperature of 20 degrees Celsius.

Two supporting studies on the water solubility are available of activated carbon (high skeletal density). Because these studies are used as read across, they are assigned with reliability 2. Also these studies were peformed according to OECD guideline 105 using the column elution method under GLP. The studies report a water solubility of < 1 mg/L as concentrations of activated carbon were found to be below the limit of quantification (1 mg/L).

Based on these three studies it can be concluded that no quantifiable dissolved amounts of chemically activated carbon were found using the column elution method (for substances with a low water solubility) and that chemically activated carbon is thus not soluble in water.