Quaternary ammonium compounds, C20-22-alkyltrimethyl, chlorides

Endpoint summary

Description of key information

 

 

ABIOTIC DEGRADATION INAIR

DIRECT PHOTOLYSIS in air
C20/C22 ATQ does not absorb light >290 nm (ozone band) and therefore a direct photolysis in air will not occur.

INDIRECT PHOTOLYSIS in air

OH radical induced indirect photolysis of C20 ATQ and C22 ATQ can be calculated with US EPA AOPWIN Program estimating low degradation half-lives (C20 homologue 9.7h, C22 homologue 9h). But as C20/22 ATQ has a Henry’s Law Constant of <1.0*10^-5Pa*m3/mole (see IUCLID Sections 4.6 & 4.8), volatilisation is not an exposure route which has to be considered. 

 

ABIOTIC DEGRADATION IN WATER

HYDROLYSIS

C20/C22 ATQ has no functional groups which could be hydrolyzed under envrionmental conditions as stated in OECD Guideline 111. In addition C20/C22 ATQ is readily biodegradable.

 

DIRECT PHOTOLYSIS in water
C20/C22 ATQ does not absorb light >290 nm (ozone band) and therefore a direct photolysis in water will not occur.

INDIRECT PHOTOLYSIS in water

OH radical induced indirect photolysis of C20/C22 ATQ in air can be estimated with US EPA AOPWIN Program estimating low degradation half-lives (C20 homologue 9.7h, C22 homologue 9h). Therefore C20/C22 ATQ may also be degraded in water by indirect photolysis if sufficent OH radicals were available. As C20/C22 ATQ is rapidly biodegraded in surface water (see IUCLID Section 5.2.2) indirect photolysis will play a minor role in degradation.

 

ABIOTIC DEGRADATION IN SOIL

 

DIRECT PHOTOLYSIS in soil

C20/C22 ATQ does not absorb light >290 nm (ozone band) and therefore a direct photolysis on soil surface will not occur.

INDIRECT PHOTOLYSIS in soil

OH radical induced indirect photolysis of C20/C22 ATQ in air can be estimated with US EPA AOPWIN Program estimating low degradation half-lives (C20 homologue 9.7h, C22 homologue 9h). Therefore C20/C22 ATQ may be degraded on soil surface by indirect photolysis but as C20/C22 ATQ is rapidly biodegraded in aerobic soils (see IUCLID Section 5.2.3) indirect photolysis will play a minor role in degradation.

 

 

A. BIODEGRADATION IN WATER - STATIC TESTS

1. General remark on Biodegradation Testing

C20/22 ATQ inhibts sludge respiration at concentrations which are normally used in Screening test on biodegradation (ready and inherent tests). From an OECD209 Test the EC10 (3h) is 9.5 mg/L and the EC50 (3h) 43 mg/L which makes clear that the test concentration has to be selected carefully not to interfere with toxicity.

2. OECD 301 Type Screening tests

An OECD 301B CO₂Evolution test was carried out at 10 and 5 mg/L test concentration for 28d. The biodegradation rate was higher at the lower concentration (see Table 5.2-1) but at these test concentrations the test criteria for ready biodegradation was not achieved. When carrying out the OECD 301B with [14C]-C22 ATQ at a test concentration of 0.2 mg/L the formation of CO₂reached 80% after 28d.

 

Table 5.2-1  OECD 301 B Biodegradation results (see IUCLID Chapter 5.1.2) after 28d

Test material	Test conc. (mg/L)	Formation of CO2 (%)
C20/22 ATQ	10	21
C20/22 ATQ	5	40
[14C] C22 ATQ	0.2	80
C18 TMAC	1	77 (O2 Consumption)

 

 

C20/22 ATQ is readily and ultimately biodegradable at a concentration of 0.2 mg/L being which is higher than the STP influent concentration e.g. for manufacturing and cosmetic use of C20/22 ATQ.

In an Enhanced OECD 301D Closed bottle test (see REACH Guidance Document) at 0.5-2 mg/L different test settings were applied. For example Humic acid and river water with silica gel was used and the exposure time expanded up to 60 days. In two of the four test setting biodegradation exceed the test criteria of 60% but only after 60d.

A second study was conducted to determine the biodegradation in water of the test substance, C18 TMAC (99.5% active) according to OECD guideline 301D, EU Method C.6 and ISO 10707 (Closed Bottle test), in compliance with GLP. The test was performed with activated sludge, domestic in 0.30L BOD (biological oxygen demand) bottles with glass stoppers. There were 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with the test substance. The concentrations of the test substance, and sodium acetate in the bottles were 1.0, and 6.7 mg/L, respectively. (A slight inhibition of the endogenous respiration of the inoculum by the test substance was detected at day 7. Therefore, limited inhibition of the biodegradation due to the "high" initial concentration of the test compound is expected. This toxicity was the reason for testing at an initial test compound concentration of 1.0 mg/L). The test substance was biodegraded by 77% and 73% by the end of 28 days using and ThODNH3 and ThODNO3 equations respectively. The test was valid, as shown by an endogenous respiration of 1.1 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 66% of its theoretical oxygen demand after 14 day. Oxygen concentrations remained >0.5 mg/ L in all bottles during the test period. Under the study conditions, the test substance can be considered readily biodegradable (van Ginkel, 2005).

.

OECD 303A C20/22 ATQ Simulation Test Activated Sludge Unit -Aerobic Sewage Treatment
C20/22 ATQ was continuously dosed into the activated sludge unit resulting in an influent concentration of 300 µg/L (41 µg/L C20 isomer, 243 µg/L C22 isomer). Influent and effluent concentration of C20/22 ATQ were measured daily using LC MS MS (LOQ C20influent= 4.1 µg/L, C22 24.3 µg/L; LOQ C20effluent= 2.1 µg/L, C22 12.1 µg/L). Already one day after the start of the test the elimination of C20/22 ATQ was > 99% (C20 and C22 fraction). Biodegradation of C20/22 ATQ has started immediately and reached a maximum of 98% during the plateau phase. Biodegradation of the C20 fraction was 94-98% (median 96%) and of the C22 fraction 87-93% (median 91%).

 

 

OECD 308

Docosyltrimethylammonium Chloride (DTAC) was steadily degraded in two water-sediment systems to carbon dioxide.  Dissipation rates of DTAC from the water phases in the Calwich Abbey and Lumsdale systems, under the experimental conditions gave DT50 (water) values of 4.16 days and 1.19 days, respectively.  Disappearance times calculated for DTAC in the total system under the experimental conditions gave DT50 (total) values of 29.0 days and 56.7 days obtained for Calwich Abbey and Lumsdale sediment systems, respectively.

 

OECD 309

[14C]Carbon dioxide was a major product of degradation in both the low and high application rate of the surfactant [14C]Docosyltrimethylammonium chloride.  The rate of transformation was moderate and consistent throughout the study, where the DT50 (half-life) was 101 and 166 days for the high and low application rates respectively.  No major metabolites were identified, but one minor metabolite was present within the high application rate vessels and identified as desaturated [14C]Docosyltrimethylammonium chloride (– 2H).

 

OECD 307 Aerobic Transformation in Soil, Key study

 

According Annex IX, Section 9.2.1.3 column 2 of the REACH Regulation 1907/2006/EC a Soil simulation test need not to be carried out if the substance is readily biodegradable. Nevertheless available information is provided using read across from the supporting substance C22-ATQ (CAS 17301-53-0). The degradation rate of 14C-C22 -ATQ in three aerobic soils was investigated during 124 days. The 14C-labelled substance was applied at a rate of 0.2 mg a.i./kg soil dw. using sewage sludge as carrier. The application rate was determined from an exposure modelling using realistic use rates. Soil sampling was done after 3, 7, 14, 29, 62 and 124 days. Significant amounts of radioactive carbon dioxide and bound residues were formed. The total mean recoveries of radioactivity were in the range of 105 to 107% for the three soils. From the measurements the following DT50 for biotransformation were calculated:

 

DT50 soil 1: 23.2 d;

DT50 soil 2: 24.9 d;

DT50 soil 3: 41.4 d,

 

 

 

Aquatic bioaccumulation

 

An uptake of all analyzed compounds C18_ATQ, C20_ATQ and C22_ATQ of the test item in fish was observed. Since no steady-state phase was reached during uptake, no steady-state bioconcentration factors were calculated. The kinetic bioconcentration factors have been calculated based on fish body weight and time-weighted average mean measured concentrations of the test item compounds C18_ATQ, C20_ATQ and C22_ATQ in water during uptake phase.

The results showed an ambiguous finding regarding the carbon chain length. Due to the high adsorption of the test substance it can be assumed that a certain amount of the substance is adsorbed on the fish skin. In order to differentiate between the fraction on the fish skin and the fraction in the fish fillet, further investigations were necessary. The results of this distribution in fish (fillet and skin) ends in the following BCFs

 

Nominal test concentration [µg/L]		5.00	20.0
BCFKGL	C18_ATQ	1787	957
	C20_ATQ	1263	920
	C22_ATQ	691	351
Weighted BCFKGL [L * kg^-1]		835	465

 

All BCFs of the 3 chain lengths and of the two concentrations are below 2000.

 

C20/22 ATQ is a quaternary substance and positively charged. It is known that ionic compound have a low potential to cross membranes.

 

 

Terrestrial bioaccumulation                                                                                   

C20/22 ATQ is a quaternary substance and positively charged. It is known that ionic compound have a low potential to cross membranes. In addition C20/22 ATQ has a low measured Log Kow of 3.3 (see IUCLID Section 4.7) and therefore a bioaccumulation potential in soil is unlikely. It can be concluded that the substance is rapidly biodegraded/transformed in soils (see IUCLID Section 5.2.3). The half-life determined from three different soils for C22-ATQ was 28.5 days (geometric mean).

 

 

[14C]-C22 ATQ Adsorption Desorption test according OECD 106

Cationic surfactants do not only sorb via van der Waal forces but also by ionic interactions (e.g ion pair formation, cation exchange). So far no mechanistic model exists to estimate the sorption behaviour of these substances. Therefore measurements are warranted to address the sorption to solid phases reliably. Sorption was measured in three different soils, one sediment and one secondary sludge. The Freundlich isotherms for the different matrices are non-linear (1/n < 1). As the lowest tested concentration is used for the exposure assessment Table 5.4-1 below lists the Kd and Koc at that concentration which allows to judge the sorption behaviour without a calculation excerise using the Freundlich isotherm.

  

Table 5.4       Sorption behaviour of [14C]-C22 ATQ to different solid matrices

 

SOIL		% OC		% Clay		CEC (Meq/100g)	Kd (L/kg) lowest conc.Measured		Koc (L/kg) lowest conc.Measured
Cranfield 164		3.7		28		22.8	2028
		3.7		28		22.8	1856
Cranfield 277		2.7		57		8.3	12326
		2.7		37		8.3	17013
Cranfield 299		2.9		26		14.9	3670
		2.9		26		14.9	5295
mean		3.1		34		15.3	7031		226807
median		2.9		28		14.9	4483		154569
SEDIMENT
SW		11.1		35		47.3	1178
		11.1		35		47.3	2449
mean		11.1		35		47.3	1814		29250
SLUDGE
secondary (activated)		39.0		64		129	267
		39.0		64		129	281
mean		39.0		64		129	274		731

 

 The Koc values from the OECD 106 study were used in the Environmental exposure assessment of C20/22 ATQ carried out with the EUSES model. As EUSES assigns certain percentages of organic carbon (OC) to the different compartments, Kd values for EUSES were calculate from the available Koc as given in the table 5.4-2

  

Table 5.4-2    Recalculation of Sorption constants for C22 ATQ to values which can be used in the EUSES Exposure assessment

 

	OECD106 results at 10 µg/L		EUSES STANDARD VALUES %OC and Kd related to Koc
SOIL
	% OC	Koc (L/kg) average lowest conc.Measured	% OC EUSES	Kd (L/kg) EUSES based on EUSES OC	EUSES Term for Compartment
Cranfield 164	3.7	52486
Cranfield 277	2.7	543315
Cranfield 299	2.9	309138
mean	3.1	226807	2	4536	SOIL
SEDIMENT
SW	11.1	29258	5	1463	SEDIMENT
SLUDGE
secondary (activated)	39.9	731	37	270	ACTIV. SLUDGE

 

  

Henry’s Law Constant (HLC)

The HLC of C20/22 ATQ can be calculated from vapour pressure (IUCLID Section 4.6) water solubility (IUCLID Section 4.8). The Exposure assessment tool EUSES 2.1 recalculates the HLC of 3.6*E-3 Pa*m3*mol-1at 25 degree C to 1.7*E-3 Pa*m3*mol-1at the environmental temperature of 12 degree C. The dimensionless air-water partitioning coefficient is calculated to 7.4*E-7 m3/m3. The HLC shows that volatilisation of C20/22 ATQ from aqueous solutions is very low.