Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

TEA-Esterquats are readily biodegradable, biodegradable under anaerobic conditions and under different environmental conditions (water, sewage treatment plants). Due to the ready biodegradability and the anaerobic biodegradability biodegradation does not need to be investigated further according to REACH Regulation (Annex IX, 9.2.1.4, column 2) and column 2 of REACH Regulation Annex IX, 9.2.1.3.

 

 

Public available data from a HERA Risk Assessment report was evaluated in order to gather values to be used for CSA:

Soil: Low levels of undegraded esterquats may reach the soil compartment via agricultural use of digester sludge. Degradation of DEEDMAC in sludge amended soils was investigated by Giolando et al. [1995]. The evolution of14CO2was monitored for up to 142 days. The extent of mineralisation ranged from 52 to 72% and the half-life for mineralisation was 14-18 days [Giolando et al., 1995]. DEEDMAC can therefore be classified as biodegradable in soils. Supporting data was given in the HERA RAR for HEQ, showing that the half-life for mineralisation of HEQ in soil is 2 to 3 weeks. Comparably high biodegradability test results of all esterquats under aerobic and anaerobic conditions justify a half-life of 18 days in soils for all esterquats.

Value used for CSA:half-life in soil 18 d at 20 °C

Surface water: Based on their ready biodegradability, a default half-life value of all esterquats in surface waters of 15 days may be used as proposed by the TGD. However, it is obvious that the removal of the parent material (primary biodegradation) representing the basis for the exposure assessment within the environmental risk assessment process is at least as fast and effective as the ultimate biodegradation of these chemicals. Therefore, mineralisation kinetics data of esterquats obtained in river die-away tests can be considered a very conservative estimate of the removal rate of the esterquats in surface waters. The biodegradation study of (14C-methyl-) radiolabelled DEEDMAC in a river die-away test system revealed a mineralisation half-life time of 1.1 days (Giolando et al., 1995). A similar investigation using HEQ radiolabelled in different positions of the molecule revealed mineralisation half-lifes of <1 day (14C-stearyl-labelled) - ca. 8 days (14C-methyl) (Waters et al., 1991). The 8 day result was found in a study with radio-labeled head-group, while degradation of the unlabeled chain would actually determine the primary biodegradation rate. This allows to conclude that the half-life of the parent materials will be rather in an order of hours instead of days. This conclusion is supported by the observation that the primary biodegradation kinetics of another surfactant, LAS, in rivers corresponds to a half-life of 1-3 hours (Takada et al, 1992; Schröder, 1995) while the mineralisation half-life in a river die-away study was 18 h (HERA, 2004: RA of LAS). Based on these facts, a conservative half-life of 16 h will be used for the esterquats in this HERA risk assessment.

Value used for CSA:half-life in surface water 1.1 d at 20 °C

Sediment: No concrete data for the biodegradation kinetics of esterquats in sediments are available. A conservative estimate can be based on the approach suggested by the TGD (2003), i.e. using the half-life time for aerated soils. This approach is justified due to the ready biodegradability (according to the OECD criteria), as well as the good anaerobic biodegradability. Therefore, a half-life of 18 days in sediments for all esterquats is used as a conservative estimate.

Value used for CSA:half-life in sediments 18 days at 20 °C