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Acute aquatic toxicity profile of N-benzyl-N-C16-18 (even numbered)-alkyl-N-methyl-C16-18 (even numbered)-alkyl-1-aminium chloride has been assessed and data are available for characterizing its possible ecological impacts at different levels of the trophic chain. As no data are available for characterizing long-term effects, read-across is proposed with DHTDMAC based on structures analogies and acute toxicity profiles similarity. For DHTDMAC, depending on the study standard or river water was used. When available, it is considered more relevant from an environmental point of view to use the toxicity value of studies carried out with river water based on the intrinsic properties of the substance. Indeed, these substances are poorly soluble in water and also have a strong tendency to adsorb to negatively charged surfaces such as suspended matter, vessels or organic material (including dissolved organic matter such as humic acids). Many cationic substances in general but long chain dialkyl quats in particular rank among the most difficult substances to test in environmental toxicology. Standard guideline studies are inappropriate to test substances with such properties and the current REACH Guidance Documents do not provide sufficient guidance concerning bioavailability and exposure assessment for cationic surface-active substances like the dialkylquats as these were written with normal hydrophobic chemicals in mind, failing to take into account the lack of bioavailability that occurs in the environment with these substances. Aquatic ecotoxicity tests performed in river water are therefore considered to assess the aquatic environmental risk more realistically for these difficult substances as the use of river water in the effect assessment compensates for the difficient prediction of the bioavailability in the exposure assessment. Aquatic ecotoxicity tests performed in river water were therefore selected to allow a PECaquatic, bulk/PNECaquatic, bulkapproach. This is considered to be conservative but more environmentally realistic than the standard method. This approach is thus based on PEC estimations representing "total aquatic concentrations". To characterize the risk to the aquatic compartment the PECaquatic, bulkis compared with the PNECaquatic, bulkderived from river water ecotoxicity studies (ECETOC, 2001).

 In order to class standard laboratory toxicity study valid, it is of particular importance that - besides information on test substance, test method/conditions and test organism used - suitable precautions are taken to prevent the loss of test substance by adsorption and that exposure concentrations are based upon measured levels.

For ecotoxicity tests performed using the bulk approach, however, adsorption to suspended matter and DOC is acceptable and only adsorption to glassware should be accounted for. For a valid bulk approach test the concentration-effect relationship should be based on the sum of adsorbed and dissolved substance in the volume of the medium tested. One of the advantages of the bulk approach tests with these difficult substances is that in the presence of suspended matter and/or humic acids, the residual sorption to glassware will be negligible. The results of these bulk approach tests are therefore much easier to interpret, more environmental realistic, and if compared to PECbulkclearly provide a more appropriate assessment of risks for the environment.

Short-term toxicity to fish (bulk approach)

A study by M. Kean, 2010, was conducted to determine the short-term toxicity of the test material to fish.

The following results were obtained:

LC50 (96 -h): 3 mg/L

NOEC (96 -h): 2 mg/L

LOEC (96 -h): 4.5 mg/L

Long-term toxicity to fish (read-across from DHTDMAC):

As for short-term toxicity tests, it has been noticed that toxicity was dependent on the experimental conditions. Embryo larval tests were conducted with Pimephales promelas in filtered well water and natural river water. In river water the NOEC for the most sensitive parameters hatchability and mean weight of larvae was 0.23 mg/L after 33 days test duration versus 0.053 mg/L in well water considering the most sensitive parameters (weight, lenght and larvae survival).

Short-term toxicity to invertebrates

The acute toxicity (inhibition of mobility) of N-benzyl-N-C16-18 (even numbered)-alkyl-N-methyl-C16-18 (even numbered)-alkyl-1-aminium chloride to Daphnia magna was assessed according to the method C2 of the European Directive 92/69/CEE and in the guideline 202 (part I) of the OECD.

EC50 -48h = 0.66 mg/L

Long-term toxicity to invertebrates (read-across from DHTDMAC and DSDMAC)

The no observed effect concentration (NOEC) for daphnids exposed to 14C-labeled DSDMAC (considered as a good surrogate for DHTDMAC) in river water was determined to be 0.38 mg/L by Lewis and Wee in 1983. Length, total young and mean brood size of adults exposed to mean concentrations of >= 0.76 mg/L DSDMAC were significantly less (p <= 0.05) than the same parameters for adults in the controls and in the remaining test waters.

Toxicity to algae (bulk approach)

A study by M. Kean, 2010, studied the toxicity of the test material to aquatic algae. The toxicity to algae test was conducted according to approved guidelines with GLP accreditation with deviations reported and justified. This test can be considered reliable without restrictions.

The following results were obtained:

EC10 (72 -h): 0.99 mg/L (growth rate)

EC50 (72 -h): 1.87 mg/l (growth rate)

EC10 (72 -h): 0.31 mg/L (biomass)

EC50 (72 -h): 0.84 mg/L (biomass)

NOEC (72 -h): 0.51 mg/L (growth rate)

LOEC (72 -h): 1.63 mg/L (growth rate)

Toxicity to sediment organisms (read-across from DHTDMAC)

DHTDMAC toxicity toward sediment organisms has been extensively reviewed. Among all those tests, four are considered as appropriate for the effects assessment of sediment: the studies by Pittinger et al., Conrad et al., Comber/Conrad and BSB. ForChironomus ripariusa NOEC of 876 mg/kg dw was found.Lumbriculus variegatuswas less sensitive to adsorbed DODMAC. A NOEC of about 5,000 mg/kg dw was found for this sediment ingesting worm. For the nematodeCaenorhabditis elegansa NOEC of 1,350 mg/kg dw was derived. The NOEC found for the oligochaeteTubifex tubifexwas with 1,515 mg/kg dw in the same range with the NOECs from the other tests. However, a EC10-value of 550 mg/kg dw could be calculated that is used a basic value for the PNEC derivation.

Toxicity to Microorganisms

In order to predict effects of chemicals in the environment and in biological waste water treatment plants, an activated sludge respiration inhibition test was performed. The toxicity to activated sludge was determined in accordance with OECD Test Guideline 209, and in compliance with the OECD principles of Good Laboratory Practice. Based on the obtained results, quaternary ammonium compounds, benzyl bis (hydrogenated tallow-alkyl) methyl, chlorides is therefore considered not harmful to activated sludge.

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