Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The substance is a liquid at ambient temperature. It is slightly soluble in water (1.24 mg/L), has a low volatility (vapour pressure = 5.8 x 10-10Pa at 25 °C) and, by read-across, has a high affinity for soil / sediment (log Koc soil = 22.96 and log Koc sewage sludge was estimated to be 24.61). As such, any environmental release will result in virtually all of the substance compartmentalising into the sediment/soil compartment, with little release directly to atmosphere.

 

An EPIWIN estimation have been undertaken on the substance. The following partitioning data have been derived based on the EPIWIN Fugacity III model (Mackay et al. 1996):

-         Air                          0.122%

-         Water                    12.2%

-         Sediment              87.5%

-         Soil                         0.106%

 

Based on the model available, the substance will have a tendency to bind tightly primarily to sediment.

The adsorption coefficient (Koc) of read-across substance, tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate, on soil and on sewage sludge was determined using high performance liquid chromatography (HPLC) according to OECD test methods. Log Koc soil was determined to be 22.96 and log Koc sewage sludge was estimated to be 24.61. The McCall classification of soil mobility potential classifies the substance as immobile in soil.As such, significant exposure related effects to water dwelling organisms are considered to be negligible. 

Based on a bioaccumulation study in fish with a closely related structural analogue and QSAR modelling, the BCF value for the test substance is estimated to be 4.1 L/kg ww (geometric mean). Therefore, the substance is not considered to be bioaccumulative.

In a study conducted according to OECD Guideline 301B, the biodegradation of the test substance was 2% at 28 days therefore the substance is not considered to be biodegradable. Based on its low water solubility, high partition coefficient and low biodegradation rate it can be concluded that it is likely that the substance could potentially be persistent within the environment. Abiotic effects within the environment will result in eventual removal from the environment. Given the low mammalian toxicity and predicted bioaccumulation potential, it is expected that effects on organisms in the food chain can considered to be minimised. 

Finally, the test substance and closely related structural analogues demonstrate low acute toxicity in mammalian studies. As the substance is also not anticipated to bioaccumulate, in the event of exposure of higher level organisms via ingestion of environmental organisms, effects due to secondary poisoning can be excluded.