Dipropylamine

Biodegradation in water: screening tests

Description of key information

Dipropylamine is readily biodegradable (according to OECD criteria).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

As key study, the biodegradability of dipropylamine (CAS 142 -84 -7) was assessed in Manometric Respirometry Test according OECD 301F. The degradation extent of Dipropylamine based on the ThOD_(NO3) was 97.6% within 28 days, the 10-d-window was met. The test item reached the criteria for ready biodegradability (60% of ThOD within 28 days and within a 10-d window).

Furthermore, the biodegradability of the substance was assessed in an OECD 301B study with domestic activated non-adapted sludge. The substance was degraded to 80% after 28 d based on CO₂evolution (BASF AG, 2005)). No estimation of exposure concentrations was performed in this study. However, according to ECETOC TR no. 123 “Assumptions regarding the aqueous solubility of the ionized species will reflect how the air-water equilibrium partitioning, or Henry’s Law constant, is defined. In this instance, it is generally assumed that the ionized species is non-volatile and will not be presented in the gas phase”. Dipropylamine will be present in its ionized form at environmentally relevant conditions (pKa = 11). Therefore, it is considered that the test substance was stable during the study.

I order to support the experimental data for dipropylamine, the biodegradation potential of the structurally similar substance diethylamine (CAS 109 -89 -7) was assessed in a modified MITI test according to OECD 301C. Mixed inoculum from 10 different sampling sites was used. After 28 days, a degradation (based on O₂consumption, BOD(NO₂)) of 69% was observed (NITE, 1992).

In conclusion, based on the existing experimental data for the target substance itself, dipropylamine is readily biodegradable (according to OECD criteria).