Calcium cyanamide

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Available experimental data for cyanamide are used in a read-across approach for the assessment of calcium cyanamide technical grade:
For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Type:

Pow

Partition coefficient:

0.19

Temp.:

20 °C

pH:

ca. 6.8

Key result

Type:

log Pow

Partition coefficient:

-0.72

Temp.:

20 °C

pH:

ca. 6.8

Type:

log Pow

Partition coefficient:

ca. -0.81

Temp.:

20 °C

pH:

ca. 7

Remarks on result:

other: QSAR prediction

Details on results:

The detector calibration for the UV analysis was found to be a curve over the range 1.0 to 25.7 mg/L of standard solutions hence a polynominal regression was applied.
The mean recoveries of Cyanamid F1000 from the method verification samples were as follows: Cyanamid F1000 in n-octanol and in water showed a recovery of 101 % and a RSD (n = 4) of 10.5 and 1.1 respectively. These results indicate that the analytical methods were accurate in the quantification of the test substance in both n-octanol and water.
Results of the test showed a measured Pow value of 0.2 (log Pow = 0.70).

Determination of the partition coefficient of Cyanamid F1000 between n-octanol and water

Sample	A	B	C	D	E	F
n-octanol volume (ml)	15	15	20	20	10	10
Cyanamid F1000 in n-octanol (mg/l)	33.45	32.07	57.12	59.59	19.26	24.75
Total Cyanamid F1000 in n-octanol (mg)	502	481	1140	1190	193	248
Water volume (ml)	15	15	10	10	20	20
Cyanamid F1000 in water (mg/l)	179.7	175.8	311.1	301.6	94.88	95.61
Total Cyanamid F1000 in water (μg)	2700	2640	3110	3020	1900	1910
Total Cyanamid F1000 added (μg)	3440	3440	4580	4580	2290	2290
Total Cyanamid F1000 recovered (μg)	3200	3120	4250	4210	2090	2160
pH of water phase after partition	6.8	6.7	6.8	6.9	6.8	6.8
Pow	0.186	0.182	0.184	0.198	0.203	0.259*
Log10Pow	-0.730	-0.739	-0.736	-0.704	-0.693	-0.587*

* value not included in the mean calculations as it is considered to be outlier under the Dixon criterion, at the 5% significance level.

 Mean P_ow = 0.19

Standard deviation = 0.01

 Mean log P_ow = –0.72

Standard deviation = 0.02

Conclusions:

The (mean) octanol/water partition coefficient of Cyanamid F1000 was found to be 0.19 ± 0.01 (mean log Pow = -0.72 ± 0.02) at 20°C.

Available experimental data for cyanamide are used in a read-across approach for the assessment of calcium cyanamide technical grade:
For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Executive summary:

The partition coefficient (octanol-water) of Cyanamid F1000 was determined using the shake flask method according to OECD guideline 107 and EU method A.8 at 20°C. The octanol-water partition coefficient, P_ow, of Cyanamid F1000 was determined to be 0.19 ± 0.01 (log P_ow = –0.72 ± 0.02) at 20 °C. QSAR prediction result in a log P_ow of –0.81, which is in very good agreement with the experimental value.

This information is used in a read-across approach in the assessment of the target substance.

For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

 

Reference 2

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

2017-10-24 to 2017-10-25

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
KOWWIN v1.68; integrated within the Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11;

2. MODEL (incl. version number)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C(#N)N

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Explanations are derived from the on-line KOWWIN™ User's Guide (v1.68). KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate. KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values. KOWWIN’s "reductionist" fragment constant methodology (i.e. derivation via multiple regression) differs from the "constructionist" fragment constant methodology of Hansch and Leo (1979) that is available in the CLOGP Program (Daylight, 1995). See the Meylan and Howard (1995) journal article for a more complete description of KOWWIN’s methodology.

5. APPLICABILITY DOMAIN
- All constituents fall within the Molecular Weight ranges domain.
- No substance has functional groups or features not in the training set of the model and/or for which no fragment constants and correction factors available
- No constituents contain multiple fragment instances than the maximum of the training set

6. ADEQUACY OF THE RESULT
- The QSAR model is scientifically valid.
- The substance falls within the applicability domain of the QSAR model
- The prediction is fit for regulatory purpose

Qualifier:

according to guideline

Guideline:

other: REACH guidance on information requirements and chemical safety assessment, chapter R.6: QSARs and grouping of chemicals, May 2008.

Principles of method if other than guideline:

QSAR calculation using the fragment constant methodology

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

-0.81

Remarks on result:

other: QSAR calculation

Details on results:

The estimated log Kow for Cyanamide is very low and suggests hydrophilic properties associated with a minor potential for adsorption and bioaccumulation.

Cyanamide

- is inside of the molecular weight range of the training set compounds (ca. 18–720 g/mol),

- does not have more instances of a given fragment than the maximum for all training set compounds.

- does not have additional functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed.

Therefore, Calcium cyanamide is considered to be in the applicability domain of the model.

Conclusions:

The estimated log Kow for Cyanamide of -0.81 is very low and suggests hydrophilic properties associated with a minor potential for adsorption and bioaccumulation.
The final result is considered adequate for a regulatory conclusion.

Executive summary:

The octanol-water partition coefficient of Cyanamide was estimated by QSAR calculation using EPISuite 4.1/KOWWIN v.1.68. The estimated log Pow of -0.81 is relatively low and suggests hydrophilic properties associated with a decreased potential for adsorption and bioaccumulation.

Reference 3

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004-12-13

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

photometric method

Key result

Type:

Pow

Partition coefficient:

0.19

Temp.:

20 °C

pH:

ca. 6.8

Key result

Type:

log Pow

Partition coefficient:

-0.72

Temp.:

20 °C

pH:

ca. 6.8

Details on results:

The detector calibration for the UV analysis was found to be a curve over the range 1.0 to 25.7 mg/L of standard solutions hence a polynominal regression was applied.
The mean recoveries of Cyanamid F1000 from the method verification samples were as follows: Cyanamid F1000 in n-octanol and in water showed a recovery of 101 % and a RSD (n = 4) of 10.5 and 1.1 respectively. These results indicate that the analytical methods were accurate in the quantification of the test substance in both n-octanol and water.
Results of the test showed a measured Pow value of 0.2 (log Pow = –0.70).

Determination of the partition coefficient of Cyanamid F1000 between n-octanol and water

Sample	A	B	C	D	E	F
n-octanol volume (ml)	15	15	20	20	10	10
Cyanamid F1000 in n-octanol (mg/l)	33.45	32.07	57.12	59.59	19.26	24.75
Total Cyanamid F1000 in n-octanol (mg)	502	481	1140	1190	193	248
Water volume (ml)	15	15	10	10	20	20
Cyanamid F1000 in water (mg/l)	179.7	175.8	311.1	301.6	94.88	95.61
Total Cyanamid F1000 in water (μg)	2700	2640	3110	3020	1900	1910
Total Cyanamid F1000 added (μg)	3440	3440	4580	4580	2290	2290
Total Cyanamid F1000 recovered (μg)	3200	3120	4250	4210	2090	2160
pH of water phase after partition	6.8	6.7	6.8	6.9	6.8	6.8
Pow	0.186	0.182	0.184	0.198	0.203	0.259*
Log10Pow	-0.730	-0.739	-0.736	-0.704	-0.693	-0.587*

* value not included in the mean calculations as it is considered to be outlier under the Dixon criterion, at the 5% significance level.

 Mean P_ow= 0.19

Standard deviation = 0.01

 Mean log₁₀P_ow= –0.72

Standard deviation = 0.02

Conclusions:

The (mean) octanol/water partition coefficient of Cyanamid F1000 was found to be 0.19 ± 0.01 (mean log10Pow = -0.72 ± 0.02) at 20°C.

Executive summary:

The partition coefficient (octanol-water) of Cyanamid F1000 was determined using the shake flask method according to OECD guideline 107 and EU method A.8 at 20°C. The octanol/water partition coefficient, Pow, of Cyanamid F1000 was determined to be 0.19 ± 0.01 (log Pow = -0.72 ± 0.02) at 20°C.

Description of key information

The partition coefficient of calcium cyanamide technical grade is evaluated by means of data on its corresponding acid (cyanamide, CAS # 420-04-2) by read-across. Both measured data and a QSAR calculation are available for cyanamide. The QSAR-predicted partition coefficient is log P_ow = –0.81, the measured result is log P_ow = –0.72.

For the calcium cyanamide technical grade the value is expected to be even lower due to its ionic nature.

By weight-of-evidence, in view of the good agreement between theoretically estimated and experimentally determined values, the latter (log P_ow = –0.72) is adopted as a worst-case figure (potentially highest bioaccumulation and/or adsorption probability).

Nevertheless, the worst-case figure for the partition coefficient indicates negligible bioaccumulation and adsorption potential of the substance.

Key value for chemical safety assessment

Log Kow (Log Pow):

-0.72

at the temperature of:

20 °C

Additional information

Available experimental data for cyanamide are used in a read-across approach for the assessment of calcium cyanamide:

Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide. Thus, upon release of calcium cyanamide to water the environmental distribution and exposure is driven by the physico-chemical/fate properties of hydrogen cyanamide.