Quaternary ammonium compounds, di-C12-18-alkyldimethyl, chlorides

Toxicity to terrestrial arthropods

Administrative data

Endpoint:

toxicity to non-target arthropods on inert substrate (NTA other than pollinators)

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Overall, the ionic nature of the test substance supported with the predicted and experimental read across BCF values indicates a low bioaccumulation potential. Considering a conservative approach, the higher BCF value of 71 L/kg ww from the QSAR study with the test substance has been considered further for hazard/risk assessment. 

BCF (aquatic species):

71 L/kg ww

Study 1:The BCF value for the test substance were estimated using the regression-based methodology of the BCFBAF v3.01 program (EPI Suite v4.11). Since the test substance is a ionic and UVCB with similar constituents varying mainly in carbon chain lengths, the BCF values were predicted for the individual components using regression method, followed by the determination of an overall weighted-average. SMILES codes were used as the input parameter. Based on the regression-based method for ionic substances and log Kow values for the individual constituents, the BCF values were predicted to be 70.8 L/kg ww (log BCF = 1.85) (US EPA, 2020)indicating a low bioaccumulation potential. On comparing with domain descriptors, not all constituents were found to meet the log Kow domain criteria as defined in the BCFBAF user guide of EPISuite. Further, taking into consideration the model’s training set and validation set statistics and the fact that the training set only contains 61 ionic compounds, the BCF predictions for the individual constituents are considered to be reliable with moderate confidence.

Study 2: A study was conducted to determine the aquatic bioaccumulation of the 14C-radiolabelled read across substance, C16-18 DAQ in Lepomis macrochirus (bluegill fish) under continuous flow-through conditions, according to OECD 305. The bluegill were exposed to nominal 20 µg/L concentrations of 14C-labeled test substance in aerated, carbon-filtered well water and to 23 µg/L in town river water under continuous flow conditions for 49 days, followed by a 21-d depuration period.. No solvent was used in the two tests. The 14C-test substance equilibrated in the test waters for 13 d prior to introducing the fish into the 30 L glass test chambers. The 115 fish in the two exposure aquaria and the 50 fish in the two control tanks were fed trout chow daily during testing. The river water was sampled at Town River, Massachusetts, and contained 2-84 mg/L suspended solids, 0.04-0.59 mg/L MBAS (methylene blue active substances) and 10-15 mg/L DBAS (disulfine blue active substances). The pH ranged from 6.4-7.7 and total hardness was 14-38 mg/L (CaCO3). Radiometric analyses in the selected fish tissues revealed that the mean steady state bioconcentration factor (BCF) in the non-edible (viscera) and whole-body fish tissue during the 49 days of exposure to be 94 and 13 L/kg ww in river water and 256 and 32 L/kg ww in well water respectively. In both waters, the test substance did not concentrate to a significant degree in edible tissue (BCF of the fillets < 5 L/kg). In a depuration phase in well water, 93% of the accumulated radioactivity was eliminated from the inedible tissues after 14 days. Overall, these results demonstrated that testing cationic surfactants under more realistic conditions (in river water) give lower bioavailability compared to studies using laboratory water (Lewis & Wee, 1983). Under the conditions of the study, the whole body bluegill BCF values were determined to be 13 L/kg ww in river water and 32 L/kg ww in well water, indicating a low bioaccumulation potential (Lewis, 1983).Based on the results of the read across study, similar low bioaccumulation potential can be expected for the test substance.

Besides these studies, the following table gives an overview of the available bioconcentration/bioaccumulation data on the read across substance C18 DAQ (also known as DODMAC) which has been litsted and reviewed in its EU RAR (EU, 2002) and the ECETOC Technical Report No. 53 (ECETOC, 1993). References mentioned below can be found in these two reports as well.

Env. Compartment	Endpoint	Type	Value	Accumulation potential	Remark
Freshwater	BCFfish	measured	13 L/kg wwt.	low	Lewis et al, 1983
Freshwater sediment	BSAFsediment	measured	0.28	low	Conrad, 1999
Freshwater sediment	BSAFsediment	measured	0.78	low	Comber, 2000
Soil	BCFworm	estimated	3 L/kg wwt.	low	estimated from BCFfish

In the EU RAR, the following assessment of the data is given:

The short-term uptake (24 h) of C18 DAQ by juvenile Pimephales promelas was assessed in a flow-through system with laboratory water and two different concentrations of humic acids (Versteeg & Shorter, 1992). A depuration phase of 72 hours followed. Compared with the laboratory water controls 6.8 mg/L humic acids decreased the uptake rate by a factor of 20 and increased the depuration rate two-fold.

These values together with the results from the study with C16 -18 and C18 -unsatd. DAQ (Lewis et al., 1983), indicate the dependence of the BCF-values on the surrounding medium which is also obvious in ecotoxicological testing. Based on test results with laboratory water, a bioaccumulation is indicated, but it is assumed that it is low under environmental conditions. A BCF of 13 L/kg is used in the risk assessment, assuming fish to be representative for all aquatic organisms. It should be pointed out, that for the diversity of organisms and environmental conditions the bioaccumulation potential (bioconcentration and biomagnification) is not known. A relatively simple microcosm study might clarify these uncertainties.

Bioaccumulation of 14C-labelled C18 DAQ by Lumbriculus variegatus from a natural sediment was measured over a period of 28 days. The total organic carbon content of the sediment was 1.73%. Worms were exposed to the C18 DAQ concentrations in the sediment in the range of 150 - 5800 mg/kg dw. After 28 days the C18 DAQ tissue concentration in the worms was measured by liquid scintillation counting. A Biota Sediment Accumulation factor (BSAF) of 0.28 was derived from the experimental data. As the concentration in the worms was only measured at the end of the 28 day test period it is not clear whether equilibrium was reached (Conrad et al., 1999).

The aim of a second experiment was the identification of the main uptake routes of C18 DAQ by Lumbriculus variegatus from the sediment. For this test feeding and non-feeding worms were exposed to a sediment containing 8.7 mg/kg of C18 DAQ. A viable non-feeding worm was generated by removing the head of an intact feeding worm. The new worm is unable to ingest sediment for up to 6- 8 days. The use of non-feeding worms allows the contribution of ingestion as an uptake route to be assessed. A 13 day bioaccumulation study with feeding and non-feeding Lumbriculus variegatus showed that the main route of uptake for C18 DAQ was via sediment ingestion. At Day 5 a comparison of tissue concentrations between the feeding and non-feeding worms showed that around 86% of the body burden in the feeding worms could be attributed to ingestion (Conrad et al., 1999).

Bioaccumulation of14C-labelled C18 DAQ by Tubifex tubifex from a natural sediment was measured over a period of 28 days. The total organic carbon content of the sediment was 1.73%. Worms were exposed to the C18 DAQ concentrations in the sediment in the range of 300-5000 mg/kg dw. After 28 days the C18 DAQ tissue concentration in the worms was measured by liquid scintillation counting. A BSAF of 0.78 was derived from the experimental data. As the concentration in the worms was only measured at the end of the 28 day test period it is not clear whether equilibrium was reached (Comber/Conrad, 2000).

To evaluate the uptake of C18 DAQ (purity > 98%) by plants, soil experiments were conducted with tomato, bean, cucumber and radish seedlings. C18 DAQ was applied to soil adsorbed to activated sludge (2 g/kg) and a concentration of 2 mg DODMAC/kg soil was achieved. Concentrations of 0.02 to 0.05 mg/kg were found in the shoots of the plant seedlings and the radish roots after 28 to 36 days exposure (Lötzsch et al., 1984).

Overall, the ionic nature of the test substance supported with the predicted and experimental read across BCF values indicates a low bioaccumulation potential. Considering a conservative approach, the higher BCF value of 71 L/kg ww from the QSAR study with the test substance has been considered further for hazard/risk assessment. 

Cross-reference 2

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Based on the results of the study with adult earthworms, the 56 day NOEC of the test substance for effects on reproduction was determined to be 500 mg/kg soil dw (nominal).

Short-term EC50 or LC50 for soil macroorganisms:

1 000 mg/kg soil dw

Long-term EC10, LC10 or NOEC for soil macroorganisms:

500 mg/kg soil dw

A study was conducted to evaluate the chronic toxicity of the test substance, C12-18 DAQ (99.6% active) to adult Eisenia fetida, according to OECD guideline 222 and ISO 11268-2 in compliance with GLP. Adult earthworm (Eisenia fetida), with clitellum and weight range 300 to 599 mg and 9 to 10 m old from in-house culture was used in the study. Ten adult earthworm per replicate were allocated to an artificial soil containing 62.5, 125, 250, 500 and 1000 mg a.i./kg soil dw (nominal concentrations) for 56 days. No analytical dose verification was performed. Assessment of adult worm mortality, behavioural effects and biomass development was carried out after 28 d exposure of adult worms in treated artificial soil. Reproduction rate (number of offspring) was assessed after additional 28 d (assessed 56 d after application). No mortality was observed in any treatment group, except at the control, where one worm died. The body weight change of the earthworms after 4 weeks exposure to test material was not statistically significantly different compared to the control up to and including the highest test concentration of 1000 mg test material/kg soil dw. The reproduction rates were not significantly different compared to the control up to and including the test concentration of 500 mg test material/kg dry soil. At the highest test concentration of 1000 mg/kg soil dw the reproduction was significantly reduced compared to the control. No behavioural abnormalities were observed in any of the treatment groups. The feeding activity in all the treated groups was comparable to the control. Under the study conditions, the NOEC of the test substance for mortality, growth and feeding activity of the earthworm Eisenia fetida was determined to be 1000 mg/kg soil dw (highest tested conc), whereas the NOEC for reproduction was determined to be 500 mg/kg soil dw (Witte, 2010).

The above study is supported by the results from a study with the read across substance C16 -18 DAQ, which has been reported in the EU RAR on DODMAC (or C18 DAQ) (EU, 2002) and has been summarised below:

In the study, Eisenia fetida was exposed to C16-18 DAQ (solved in methanol, 76.1% active ingredient) incorporated into artificial soil consisting of 9.4% organic matter, 70% fine sand and 20% kaolinite clay (Coulson et al. (1989). At the only concentration of the definitive test with 1,000 mg active ingredient/kg dry soil no mortality, no significant reduction in body weight nor any behavioral effects were observed after 14 days.