Acid chlorides, coco

Bioaccumulation: aquatic / sediment

Description of key information

Parent compounds and corresponding acids: Significant accumulation in organisms is not expected.
However, the assessment of the bioaccumulation potential of the parent compound may be of low relevance due to the rapid hydrolysis of the acid  chloride in aqueous solutions.

Additional information

A study is not required for this tonnage band.

 

Acid chlorides, coco

The substance is a mixture of the following components which hydrolyse rapidly in water to form HCl (CAS 7647-01-0) and the corresponding acid.

1) Lauroyl chloride (CAS 112-16-3): >=30 to <=70%
(hydrolysis product: lauric acid, CAS 143-07-7)

2) Tetradecanoyl choride (myristoyl chloride; CAS 112-64-1): >=10 to <=30%
(hydrolysis product: myristic acid, CAS 544-63-8)

3) Palmitoyl chloride (CAS 112-67-4): >=1 to <=20%
(hydrolysis product: palmitic acid, CAS 57-10-3)

4) Decanoyl chloride (CAS 112-13-0): >=1 to <=15%

(hydrolysis product: decanoic acid, CAS 334-48-5)

5) Stearoyl chloride (CAS 112-76-5): >=1 to <=15%

(hydrolysis product: stearic acid, CAS 57-11-4)

6) Octanoyl chloride (CAS 111-64-8): <=1 to <=10%

(hydrolysis product: octanoic acid, CAS 124-07-2)

The assessment of the bioaccumulation potential of the parent substances may be of low relevance due to the rapid hydrolysis of the acid chlorides in aqueous solution, therefore the assessment is mainly based on the corresponding acids as their hydrolysis products.

 

Experimental data are available only for the structurally similar substance sodium laurate (CAS 629 -25 -4). In a study similar to OECD 305E using Danio rerio as test organism, the BCF was determined to be 252 ± 19 L/kg (conc. 2.0 to 3.6 mg/L, nominal; Van Egmond et al., 1999; also cited in ECHA, 2012). The study was selected as key study although some deficiencies were detected (e.g., steady state only assumed based on log Kow, sampling of fish only at end of exposure, depuration phase not studied).

 

In addition QSAR estimates were calculated with 5 models for each of the hydrolysis compounds. The following models were used to estimate the BCF:

1) BCFBAF: EPI Suite v4.01, BCFBAF v3.10

2) Catalogic: OASIS Catalogic v5.11.6TB, BCF baseline model v.02.05 (listed results were calculated taking mitigating factors such as size, metabolism and the substance type (acids) into consideration)

3) TEST: US EPA T.E.S.T. v4.1

4) VEGA: CAESAR v2.1.8 (http://vega-qsar.eu)

5) UBA: Müller & Nendza (2011). Comparative analysis of estimated and measured BCF data (OECD 305). Umweltbundesamt-Texte 15, pp.

 

Only valid data were taken into consideration if information on the applicability domain was given. The following table gives an overview on the estimated data.

Hydrolysis product	CAS no.	Estimated BCF
		BCFBAF	Catalogic	TEST	VEGA	UBA
Octanoic acid	124-07-2	3.16	6	11	7	24
Decanoic acid	334-48-5	3.16	12	21.59	125	3 - 129
Lauric acid	143-07-7	3.16	34	23.33	410	27 - 684
Myristic acid	544-63-8	56.2	109	38.72	491	136 - 5082
Palmitic acid	57-10-3	56.2	99	29.05	330	461 - 49147
Stearic acid	57-11-4	10	29	12.02	58	1558 - 427805

 

The BCF data from the UBA models which is based on the log Kow only shows a wide range given for each substance. The BCF estimated by BCFBAF, Catalogic, TEST and VEGA show a good agreement, with a tendency to higher BCFs by the VEGA model. The high BCF values resulting from the UBA model should not be considered since mitigating factors like metabolism and substance type were ignored. The effect of these mitigating factors was shown to have a great effect using the Catalogic BCF baseline model where metabolism, substance type and molecular size were most effective.

 

In a weight of evidence approach using the available experimental and QSAR data, it can be concluded that the substance does not significantly accumulate in organisms (BCF < 500).