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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

Data for this PBT / vPvB Assessment are from the bis hydrogenated substance , Quaternary ammonium compounds, di- C16-18 (even numbered) -alkyldimethyl, chlorides (DHTDMAC), CAS No. 92129-33-4.


Based on the conservative degradation half-life of DHTDMAC derived in the EU Risk Assessment DODMAC/DHTDMAC, 2002, (EUR 20397 EN/2, ISSN 1018-5593) of 150d for surface water the 'P' criteria of the PBT/vPvB Assessment is fulfilled. For sediment and soil even more conservative half-lives of 500d were derived the EU Risk Assessment. Experiences with other quats e.g. Behentrimonium chloride, CAS No. 68607-24-9 have shown that despite high sorption to sediment and soil fast biodegradation has occured. The half-lives measured were all considerably lower than the half-life criteria for P and vP.


Lepomis macrochirus was exposed to 14C-DHTDMAC for 49 days to determine the BCF for quaternary ammonium compounds, di-C16-18(even numbered) -alkyldimethyl, chlorides. The maximum BCF was found to be 13 L/kg in the non edible fraction with an elimination DT90 of 14 days. Therefore the 'B' criteria for the vPvB/PBT Assessment are not fulfilled.


For the aquatic compartment the lowest chronic NOEC from a Daphnia river water test is 62 µg/l. Due to mitigation of ecotoxicity in river water a safety factor of 10 should be applied to the river water result. This results in a chronic NOEC of 6 µg/L for DHTDMAC. Therefore the 'T' criteria of the vPvB/PBT Assessment is fulfiled.