Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.001 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
0 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0 mg/L
Assessment factor:
100
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
1.3 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
9.27 mg/kg sediment dw

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.927 mg/kg sediment dw

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
7 mg/kg soil dw

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

C16 -C18 TMAC is expected to be readily biodegradable. Therefore, it can reasonably be assumed that there is no significant long-term exposure of soil macro and micro-organisms, terrestrial plants or birds to the substance. Furthermore, based on the available information, bioaccumulation is also not of significant concern. Therefore secondary poisoning is not considered relevant and no PNEC oral for secondary poisoning was derived and no risk assessment on secondary poisoning was performed.

The data for the assessment of theecotoxicity propertiesofC16-C18 TMAC is based on the followingalkyltrimethylquaternary ammonium compounds (TMACs) with differing alkyl chain lengths and benzyl alkyldimethyl quarternary ammonium compound (ADBAC).

 

Alkyltrimethylquaternary ammonium compounds (TMACs) used for read-across:

  • quaternary ammonium compounds, coco alkyltrimethyl chlorides (R=C12-C18)
  • quaternary ammonium compounds, cetrimonium chloride (R= C16)
  • quaternary ammonium compounds, tallow alkyl trimethyl ammonium chloride (R=C16-C18 and C18 and unsaturated)
  • quaternary ammonium compounds, octadecyl trimethyl ammonium chloride (R=C18)

 

Benzyl alkyldimethyl quaternary ammonium compounds (ADBACs) used for read-across:

·        quaternary ammonium compounds, benzyl-C12-C16-alkyldimethyl, chloride (R=C12-C16)

 

The read-across is justified based on the TMACs and ADBAC core chemical structures. They are characterized by a positively charged ammonium group. In the case of TMACs, the nitrogen is bound to three methyl groups and the longer alkyl chain and in the ADBAC, one methyl group is replaced with abenzyl substituent. The positively charged quaternary ammonium group is balanced by a negatively charged chloride anion.

 

In both TMACs and ADBACs, it is the positive entity (i.e., the quaternary ammonium group) that is of importance from an ecotoxicology perspective. The chloride ion does not contribute significantly to the overall toxicity of the substance.

 

C16-C18 TMACand C12-C16 ADBAC are soluble in water and also have a strong tendency to adsorb to negatively charged surfaces such as suspended matter, algae, organic matter (including dissolved humic acids) and test vessels. This property which results in a lack of bioavailability and reduced exposure to environmental organism is particularly important to consider when assessing ecotoxicological hazards and risks associated with QAS substances on the basis of ecotoxicology studies conducted according to standard guidelines. Due to their surfactant properties and high tendency to be present at the interface between the aqueous and organic phase, cationic substances in general and long chain QAS substances in particular rank among the most difficult substances to test in environmental toxicology.

 

The aquatic (i.e., fish, daphnia, algae) toxicity and toxicity to micro and macro-organisms of the QAS substances show comparable toxicity.QAS substances are very toxic to fish, invertebrates and algae with acute LC50/ EC50values in the range of <1 mg a.i./L. Chronic toxicity, data shows that chronic exposure ofDaphnia magnato C12-C16 ADBAC does not increase the risk compared to acute exposure and this is expected to be the same for all QAS substances.

Compounds with n-alkyl chain lengths of n < 4 or n >18 are virtually inactive. ADBACs affect a number of different molecules, such as proteins and lipids. The primary mode of action against microbial cells is the interaction with cell membranes causing disruption and leakage of the cellular content by predominantly acting at the level of the cytoplasmic membrane. The action involves association of the positively charged quaternary nitrogen with the head group of acidic-phospholipids before integration of the hydrophobic tail into the hydrophobic membrane core. At high concentrations, ADBACs solubilise hydrophobic cell membrane components by forming mixed micellular aggregates. The available ecotoxicology data in simple organisms such as daphnia and algae correlate well withC16-C18 TMACand C12-C16 ADBAC and their activity on microbial cells. The chronic toxicity data show C12-C16 ADBAC is toxic to daphnia (NOEC of 0.025µg/L). Furthermore, C12-C16 ADBAC was harmful to activated sludge in an inhibition of microbial activity study, was not toxic to earthworms at the highest concentration tested (1,000 mg/kg dw of artificial soil) and did not have long-term influence on nitrogen and carbon transformations in soils based on experimental data.

Conclusion on classification

The environmental hazard assessment of C16-C18 TMAC justifies R50 classification according toEC criteria (67/548/EEC) and hazardous to the aquatic environment with the aquatic acute and chronic category 1 classification according to CLP criteria (EC 1272/2008). M factors to be applied are 10 for acute and 1 for chronic.