Registration Dossier

Administrative data

Endpoint:
toxicity to terrestrial arthropods: long-term
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Cross-referenceopen allclose all
Reason / purpose:
data waiving: supporting information
Reference
Overall, based on the available weight of evidence, the test substane can be considered to be readily biodegradable.  
Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Study 1: A study was conducted to determine the ready biodegradability of the read across substance, Coco TMAC (33% active in water), according to OECD 301D and EEC Guidelines using a closed bottle test. The test substance at 3 mg/L was incubated with sludge from activated sludge plant treating predominantly domestic waste and O2 consumption was determined over a period of 28 d. The biodegradation was calculated as the ratio of the biochemical oxygen demand to the theoretical oxygen demand. The test substance reached a biodegradation of 75% at Day 28. As evident from the biodegradation of 59% at Day 5 and 74% at Day 15, the plateau for ready biodegradability of the test substance was reached within 14 d of time point when 10% degradation occurred. Further, using C12 as the representative structure for the test substance and using ThODNO3 and ThODNH3 equations, the biodegradability of the test substance following nitrification corrections was determined to be 77% and 70% within 28 days respectively. Under the study conditions, the test substance is readily biodegradable (van Ginkel, 1989). Based on the results of the read across study, the test substance is overall considered to be readily biodegradable.  

Study 2: A preliminary study was conducted to determine the ready biodegradability of the read across substance, C16-18 and C18-unsatd. TMAC (96% active), using Closed bottle test, according to the OECD Guideline 301D. The inoculum used were: (a) activated sludge obtained from the local wastewater treatment plant and diluted to 2 mg Dry Weight (DW)/in the biological oxygen demand (BOD) bottles (b) river water without particles and spiked with mineral salts of the nutrient medium was used undiluted. Ammonium chloride was omitted from the medium to prevent nitrification. The read across substance (solvent free) and humic acid were dosed using an aqueous stock solution of 1 g/L in water. Isopropanol was dosed from a 0.1 g/L stock solution in demiwater. The tests were performed in 0.3 L BOD bottles with glass stoppers. Use was made of 3 control bottles containing only respective inoculum, 36 µg/L isopropanol (to correct for the small amount of isopropanol still present in the read across substance), and silica gel or humic acid. For the read across substance (at 2 mg/L) 3 bottles were used containing the respective inoculum and silica gel or humic acid. Silicagel and humic acid concentrations in the bottles (test and control) were 1 and 2 g /bottle and 1 and 2 mg acid/L, respectively. Each of the prepared solutions was dispensed into the respective group of BOD bottles so that all bottles were completely filled without air bubbles. The bottles were closed and incubated in the dark at temperatures ranging from 22 to 24°C. The biodegradation was measured by following the course of the oxygen decrease in the bottles using a special funnel and an oxygen electrode. The dissolved oxygen concentrations were determined electrochemically using an oxygen electrode and meter (WTW). The BOD (mg/mg) of the read across substance was calculated by dividing the oxygen consumption by the concentration of the read across substance in the closed bottle. The validity of the test is demonstrated by oxygen concentrations >0.5 mg/L in all bottles during the test period. The pH of the media was 7.4 and 7.2±0.1 (activated sludge) and 8.2 and 8.0±0.1 (river water) at the start and end of Day 42 of the test respectively. Temperatures ranged from 22 to 24°C. The inhibition of biodegradation by the read across substances is usually detected prior to the onset of the biodegradation through suppression of the endogenous oxygen consumption. The inhibition of the endogenous respiration of the inoculum was detected only at day 7 of the test for the bottles supplemented with humic acid at a concentration of 1 mg/L. The ThODNH3 and ThODNO3 of the active ingredient (active with average chain length) used to calculate the biodegradation percentages was 2.86 g/g and 3.05 g/g, respectively. The biodegradation percentages at Day 28 using activated sludge as inoculum were slightly higher compared to results achieved with river water. Using the conservative ThODNO3 to calculate the biodegradation of read across substance still >60% biodegradation was achieved within 28 days using activated sludge as inoculum and 1 g silica gel / bottle for detoxification. Under the study conditions, the read across substance was determined to be readily biodegradable with >60% biodegradation after 28 days (Geerts, 2020). Based on the results from the preliminary study with the read across substance, the test substance is overall considered to be readily biodegradable.

Study 3: OECD 301D study ongoing on another read across substance, C16 -18 TMAC. The draft study report of this study will be available by 31 March 2020.

Study 4: A study was conducted to determine the biodegradation in water of the read across substance, C18 TMAC (99.5% active) according to OECD guideline 301D, EU Method C.6 and ISO 10707 (Closed Bottle test), in compliance with GLP. The test was performed with activated sludge, domestic in 0.30L BOD (biological oxygen demand) bottles with glass stoppers. There were 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with the read across substance. The concentrations of the read across substance, and sodium acetate in the bottles were 1.0, and 6.7 mg/L, respectively. (A slight inhibition of the endogenous respiration of the inoculum by the read across substance was detected at day 7. Therefore, limited inhibition of the biodegradation due to the "high" initial concentration of the test compound is expected. This toxicity was the reason for testing at an initial test compound concentration of 1.0 mg/L). The read across substance was biodegraded by 77% at Day 28 in the Closed Bottle test. The test was valid, as shown by an endogenous respiration of 1.1 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 66% of its theoretical oxygen demand after 14 day. Oxygen concentrations remained >0.5 mg/ L in all bottles during the test period. Under the study conditions, the read across substance can be considered readily biodegradable (van Ginkel, 2005). Based on the results of the read across study, which is a worst case read across, the test substance can also be considered to be readily biodegradable.

Overall, based on the available weight of evidence, the test substance can be considered to be readily biodegradable. 

Reason / purpose:
data waiving: supporting information
Reference

Based on the results of the read across study, the test substance can also expected to undergo 64% degradation in 70 days, with DT50 value of 40 days.

Half-life in soil:
40 d
at the temperature of:
20 °C

A study was conducted to determine the aerobic biodegradation of the read across substance, C12-16 ADBAC (50% active in water) in loamy soil, using a closed bottle test for 28 days according to the US FDA Environmental Assessment Handbook, Technical Assistance Document 3.12 (1987). The study comprised two treatments: test and chemical blank control group, each with three replicates. The read across substance was added into biometers at a concentration of 10 mg carbon per 50 g soil using appropriate amount of deionised water required for bringing the soils to 50-70% of the moisture capacity. Loam was added to the biometers after the test solutions to facilitate uniform moistening of the soils by capillary action. The test was then incubated at 22 ± 3°C and run for approximately 90 d. The side tube of the biometer contained 20 mL 0.2 M KOH for absorbing carbon dioxide produced by the microorganisms. The theoretical CO2 production of the read across substance was calculated from its carbon content. The amounts of carbon dioxide were calculated by subtracting the mean carbon dioxide production in the test systems containing the read across substance and the mean carbon dioxide production level in the control blank. Biodegradation was calculated as the ratio of experimental carbon dioxide production to theoretical carbon dioxide production [ThCO2P]. Under the study conditions, there was 64% degradation of the read across substance after 70 days. This percentage of the theoretical carbon dioxide production presumes complete mineralization. The DT50 was estimated to be 40 days (van Ginkel, 1994). Based on the results of the read across study, similar degradation potential and half-life is considered for the test substance. 

Reason / purpose:
data waiving: supporting information
Reference

The results of the read across study, supported with the estimated BCF value for the test substance together with its ionic nature indicates a low bioaccumulation potential. The experimental BCF value of 79 L/kg wt-wt from the read across study has been considered further for hazard/risk assessment

BCF (aquatic species):
79 L/kg ww

Study 1: A study was conducted to determine the aquatic bioaccumulation of the read across substance, C12 -16 ADBAC (30.64% active; 98.9% radiolabeled purity) in Lepomis macrochirus (bluegill fish) under flow-through conditions, according to EPA OPP 165-4, in compliance with GLP. The blue gill fish were continuously exposed to a nominal concentration of 0.050 mg/L of the read across substance (equivalent to a measured concentration of 0.076 mg/L) in well water for 35 days, followed by transfer of 35 fish into flowing uncontaminated water for a 21-d depuration period. Sampling was carried out on Days 0, 1, 3, 7, 9, 10, 14, 21, 23, 28 and 35 for the exposure period and Days 1, 3, 7, 10, 14 and 21 for the depuration period. Water samples were collected on Day 8 of the exposure period and Day 16 of the depuration for analytic determination of the read across substance concentration. Radiometric analyses of the water and selected fish tissues revealed that the mean steady state bioconcentration factor (BCF) in the edible, non-edible and whole-body fish tissue during the 35 days of exposure to be 33, 160 and 79 L/kg. The half-life for non-edible tissue was attained between Days 14 and 21, while it could not be reached for the edible and whole-body fish tissues by the end of 21-d depuration period. By Day 21 of the depuration period, the 14C residues present on the last day of exposure in the edible, non-edible and whole-body fish tissues had been eliminated by 29, 60 and 44% respectively. Analysis of skin tissue after 35 d of exposure showed residue levels somewhat higher than those observed for edible tissue at the same sampling period, indicating that there is likely significant binding of 14C-ADBAC to the skins and scales of exposed bluegill, as expected behaviour of cationic surfactants. Under the conditions of the study, the whole body BCF of the read across substance was determined to be 79, indicating low potential to bioaccumulate (Fackler, 1989).

Study 2: The Bioconcentration factor (BCF) value of test substance, C12-18 TMAC was predicted using regression-based and Arnot-Gobas BAF-BCF models of BCFBAF v3.02 program (EPI SuiteTMv4.11). The Arnot-Gobas method, takes into account mitigating factors, like growth dilution and metabolic biotransformations, therefore the BCF values using this method is considered to be more realistic or accurate. Therefore, except for ionic, pigments and dyes, perfluorinated substances, for which it is not recommended (as of now), the Arnot-Gobas method is used preferentially used for BCF predictions. Considering that the test substance is an UVCB containing majorly ionic (e.g., (e.g., the quaternary ammonium salts) and few non-ionic constituents (e.g., amines), the BCF values were predicted using regression-based and Arnot-Gobas BAF-BCF models respectively and using SMILES codes as the input parameter. The BCF values for the constituents ranged from 3.16 to 275.3 L/kg ww (log BCF: 0.50 to 2.44), indicating a low bioaccumulation potential. On comparing with domain descriptors, all constituents were found to meet the MW, log Kow and/or maximum number of correction factor instances domain criteria as defined in the BCFBAF user guide of EPISuite. Further, given that the major constituents are structurally very similar and vary only in the carbon chain length, a weighted average value, which takes into account the percentage of the constituent in the substance, has been considered to dampen the errors in predictions (if any). Therefore, the weighted average BCF value was calculated as 72.62 L/Kg ww (Log BCF = 1.86). Overall, considering either the individual BCF predictions for the constituents or the weighted average values, the test substance is expected to have a low bioaccumulation potential. However, 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.

This is further supported by the no bioaccumulation potential evidence observed in in the two toxicokinetic studies in mammals with the read across substance, C12 -16 ADBAC (Selim, 1987 and Appelqvist, 2006). .

Also, the biocides assessment reports available from RMS Italy on Coco TMAC and C12-16 ADBAC, concluded the substances to show low potential for bioaccumulation, based on the results from the above study (Fackler, 1989) and an additional read across to DDAC for the Coco TMAC's assessment ((ECHA biocides assessment report, 2015, 2016). The report concluded the following in the Coco TMAC assessment report:Coco alkyltrimethylammonium chloride is readily biodegradable, is rapidly excreted and does not accumulate in mammals, and it adsorbs onto the fish surface where its irritating action is expressed (therefore accumulation is more related to the concentration of the administered solution). Based on these properties’ bioaccumulation is not expected to be of concern for ATMAC/TMAC. An experimental BCFwhole body of 81 L/kg was determined in a flow-through test with Lepomis machrochirus and the read across substance DDAC (Lonza Cologne GmbH and Akzo Nobel Surface Chemistry AB, same study). A very similar result was obtained for the other quaternary ammonium compound benzyl-C12-16-alkyldimethyl ammonium chloride (C12-16-BKC/ADBAC) in a fish bioconcentration test, which gave a BCFwhole body = 79 L/kg (Akzo Nobel Surface Chemistry AB, access to Lonza Cologne GmbH study). Being both studies equally reliable, the BCFwhole body = 81 L/kg is chosen because related to the lead read across substance (DDAC) and it is slightly higher than the C12-16 BKC/ADBAC endpoint.”

Overall, the results of the read across study, supported with the estimated BCF value for the test substance together with its ionic nature indicates a low bioaccumulation potential. The experimental BCF value of 79 L/kg wt-wt from the read across study has been considered further for hazard/risk assessment.

Reason / purpose:
data waiving: supporting information
Reference

In line with the C12 -16 ADBAC biocides assessment report and based on the results of the read across study, the 16-d EC50 value of 277 mg a.i./kg dw of soil obtained for Brassica alba (mustard) due to effects on growth has been considered further for hazard/risk assessment.

Short-term EC50 or LC50 for terrestrial plants:
277 mg/kg soil dw

Study 1:

A study was conducted to determine the long-term toxicity of the read across substance, C12-16 ADBAC (49.9% active in water) to terrestrial plants, according to OECD Guideline 208, in compliance with GLP. Three plant species: Sinapis alba (mustard), Trifolium pratense (red clover) and Triticum aestivum (wheat) were used. Using 0.5 L capacity plastic pots, the read across substance was first applied to natural soil at nominal concentrations of 0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0 mg a.i./kg and to sand at nominal concentrations of 0, 28.8, 55.8, 93.4, 166.8 and 300.5 mg a.i./kg. This was followed by planting of 40 seeds per replicate of the three plant species. Analytical verification was performed for the read across substance. Three parameters: emergence, dry and wet weight of the plants were observed. Emergence was recorded daily until stabilisation. The plants in natural soil and sand were harvested 16 and 14 d respectively after 50% of the control seeds had been emerged. Wet and dry weight were determined immediately after harvesting. The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control. The extraction of the active substance proved that the natural soil had a strong sorbing effect and the total recovery was not achieved even when acidified methanol was used as an extraction solvent. That was not the case with quartz sand. The EC50 values in natural soil, based on the effect on emergence and growth were 342, 309, 684 mg a.i./kg ww of soil (or 537, 634 and 1960 mg a.i./kg dw of soil) for S. alba, T. pratense and T. aestivum, respectively; while those in sand were 31, 19, 105 mg a.i./kg ww (or 73, 74 and 141 mg a.i./kg dw) of sand respectively. The difference in toxicity in the two substrates were correlated with the lower bioavailability of test substance in soil due to a stronger adsorption potential. Further, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil was considered as a reasonable worst case for representing toxicity terrestrial plant species. Under the conditions of the study, the 16-d EC50 values in natural soil, based on the effect on emergence and growth were determined to be 342, 309, 684 mg a.i./kg ww or 537, 634 and 1960 mg a.i./kg dw of soil for S. alba, T. pratense and T. aestivum, respectively (Servajean, 2004).

Study 2:

A study was conducted to determine the long-term toxicity of the read across substance, C12-16 ADBAC (49.5% active in water) to terrestrial plants, according to OECD Guideline 208, in compliance with GLP. Three plant species: Phaeolus aureus (mung beans) Brassica alba (mustard) and Triticum aestivum (wheat) were used. Each plant species was sown into treated soil and assessed for 14 - 16 days following germination. For each species, groups of 40 seeds (eight replicate pots of five seeds) were sown into a garden loam soil treated with the read across substance. Untreated controls were also included. Treatment levels for the definitive study were based on the results of a preliminary range finding study. The dose levels of the read across substance used were 156, 313, 625, 1250 and 2500 mg a.i./kg dry soil for mung beans and 12, 37, 117, 375 and 1200 mg a.i./kg dry soil for mustard and wheat. After application and sowing, the pots were checked daily and the number of seedlings emerging recorded. Survival and sub-lethal effects were recorded every day following emergence. Plants were harvested 14-16 days after germination and the wet weights were measured. The plants were then dried before being re-weighed to obtain a dry weight measurement. There was no treatment-related effect on the germination and seedling survival of any of the plant species treated with the read across substance up to the highest tested concentrations. The growth inhibition occurred at higher rates of application for all the plant species. For mung bean, there was 25-40 and 50-75% inhibition at 1250 and 2500 mg a.i./kg, respectively. For mustard, there was 75-80 and >80% inhibition at 375 and 1200 mg a.i./kg, respectively and 50-75% for wheat at 1200 mg a.i./kg. Darker pigmentation was observed for all species at the higher rates of application. Under the conditions of the study the 14-16 d EC50 values based on growth inhibition in mung beans, mustard and wheat were determined to be at 1900, 277 and 670 mg a.i./Kg dry soil respectively (Gray, 2004).

Based on the above studies, same effect levels and low toxicity potential were concluded in the biocide assessment report on C12-16 ADBAC by RMS Italy. They further stated that: “The great deviation in the effects recorded in sand

and natural soil can be attributed to the lower bioavailability of C12-16 ADBACin natural soil caused by stronger adsorption to the soil particles as consequence of several binding processes. Since the results obtained in the test with silica sand are considered unrealistic worst case, only data from the tests conducted with natural soils are taken into account (this approach was agreed at TMII2013); among these, the most sensitive species was Brassica alba with an EC50 = 277 mg/kg dw soil (US ISC), which is the endpoint to be taken into account at product authorization stage (ECHA biocides assessment report, 2015). Similar conclusions were drawn in the Coco TMAC biocides assessment report, 2016, where the endpoint was mainly assessed based on read across to DDAC apart from the EQC owned supporting study on C12-16 ADBAC. The lowest EC50 for the most sensitive plant among all the tested species, i.e., EC50 (wet weight growth) = 148 mg/kg dw soil for T. pretense exposed to DDAC and corrected for MW as EC50 = 111.0 mg a.s./kg dw (98.3 mg a.s./kg ww) was selected for risk assessment (ECHA biocides assessment report, 2016).

 

In line with the C12 -16 ADBAC biocides assessment report and given that the read across to C12-16 ADBAC can be justified for the test substance based on a category approach, the 16-d EC50 value of 277 mg a.i./kg dw of soil obtained for Brassica alba (mustard) due to effects on growth has been considered further for hazard/risk assessment.

Reason / purpose:
data waiving: supporting information
Reference

Based on the results of the read across study, the 14 d LC50 and NOEC values for the test substance is considered to be at 7070 and 517 mg a.i./kg soil dw.  

Short-term EC50 or LC50 for soil macroorganisms:
7 070 mg/kg soil dw
Long-term EC10, LC10 or NOEC for soil macroorganisms:
517 mg/kg soil dw

Study 1. A study was conducted to determine the toxicity to soil macroorganisms of the read across substance C12-16 ADBAC (49.5% active) according to OECD Guideline 207, in compliance with GLP. Six groups of forty earthworm (Eisenia foetida) were allocated to an artificial soil containing 0, 953, 1715, 3086, 5556 or 10000 mg a.i./kg soil dw (nominal concentrations). No analytical dose verification was performed. Mortality was recorded on Days 7 and 14. Worms were weighed at the beginning and end of the study. After 7 days, all worms at 10000 and 2 worms at 5556 mg a.i./kg soil dw were dead. By Day 14, one additional worm died at 5556 mg a.i./kg soil dw. A treatment-related reduction in body weight was observed. Group mean body weights were affected by treatment with read across substance at 1715 mg a.i./kg soil dw and above. Under the study conditions, the 7 and 14 d LC50 values were 7160 and 7070 mg a.i./kg soil dw, respectively and the NOEC was 953 mg a.i./kg soil dw (nominal) (Rodgers, 2004).

Study 2. A study was conducted to determine the toxicity to soil macroorganisms of the read across substance, C12 -16 ADBAC (51.7% active) according to OECD Guideline 207, in compliance with GLP. Earthworms (Eisenia foetida) were exposed to a single dose of the read across substance at nominal concentrations of 100, 180, 320, 580 or 1,000 mg/kg dw of artificial soil. No analytical dose verification was performed. The individual live weights of the worms were reported after 14 d of exposure. Other effects (pathological symptoms, behaviour of the worms) were reported after 7 and 14 d of exposure. Results of the reference test with 2 -chloracetamide show that the method was sensitive and valid. The substance did not cause a change in behaviour, weight and mortality of the earthworm at any of the tested concentrations after 14 d of exposure. This was probably due to adsorption onto soil. The highest tested concentration without mortality and any other effects was 1000 mg/kg dw. Under the study conditions, the 14 d NOEC in earthworm was 1000 mg/kg dw (or 517 mg a.i./kg dw) and the 14 d LC0 was > 1000 mg/kg dw (or > 517 mg a.i./kg dw) (Noack, 1999).

Based on the above two studies, same effect levels were concluded in the biocide assessment report on C12-16 ADBAC by RMS Italy. They further stated that: “The findings of the two tests, although different in absolute values, are not in contrast. Since the second test provides a “higher than” value corresponding to a complete lack of lethal or sublethal effects, the 14d LC50 = 7070 mg/kg dry soil (US ISC) is selected to express the acute toxicity of Alkyl (C12-16) dimethylbenzyl ammonium chloride to soil dwelling invertebrates.” While the biocides assessment report on Coco TMAC, assessed the acute toxicity to earthworms based on a study with the substance itself as well as supporting read across studies from DDAC and C12 -16 ADBAC. All three studies indicated low acute toxicity potential in earthworms. The 14d LC50 = 3260 mg a.s./kg dry soil based on the study with Coco TMAC was selected further for risk assessment.

 

Given that the read across to C12-16 ADBAC can be justified for the test substance based on a category approach, the 14 d LC50 and NOEC values of 7070 and 517 mg a.i./kg soil dw has been considered further for hazard/risk assessment.

Reason / purpose:
data waiving: supporting information
Reference

In line with the C12-16 ADBAC biocides assessment report and based on the results of the read across study, the lower 28d EC50 = 153 mg a.i./kg dw and a 28d EC10 = 83 mg a.i./kg dw soildue to inhibition of microorganisms has been considered further for hazard/risk assessment.

Short-term EC50 for soil microorganisms:
153 mg/kg soil dw
Long-term EC10 or NOEC for soil microorganisms:
83 mg/kg soil dw

Study 1. A study was conducted to determine the toxicity of the read across substance, C12-16 ADBAC (49.9% active in water) to soil microorganisms, according to OECD Guideline 216, in compliance with GLP. In this study, the inhibition of microbial nitrogen transformation was investigated in sandy loam soil by evaluating the nitrite, nitrate and ammonium formation following 28 d exposure to the read across substance. A volume of 6.04 mL of deionized water containing the read across substance was added to 50-g of soil. The samples were incubated for 7 d at 20°C and at 10% of its water holding capacity. The samples were dosed with read across substance at nominal concentrations 0, 50, 100, 200, 400, 800, 1600, 3200 and 6400 mg a.i./kg soil ww. Analytical dose verification of the stock solutions indicated good correlation with the nominal concentrations. Therefore, doses were presented as nominal concentrations. The nitrogen transformation measurements were carried out at the beginning of the test and at the end at Day 28. The activity of the microorganisms transforming nitrogen in soil was slightly inhibited at 50 mg a.i./kg soil ww. The EC50 calculated was 130 mg a.i./kg siol ww with 95% confidence limits of 80 and 190 mg a.i./kg soil ww. The EC10, EC20 and EC80 of the read across substance were determined at 70, 90 and 200 mg a.i./kg soil ww respectively. In soil not only formation of nitrate occurs but also reduction of nitrate to nitrogen gas by denitrifying microorganisms. Decrease of the nitrate concentrations in the soil was observed at 400 mg a.s./kg soil ww and higher after 28 d. This was probably the result of the activity of these denitrifying microorganisms. The denitrifying microorganisms were inhibited at 6400 mg a.i./kg soil ww, as only a limited amount of the nitrate was removed after 28 d at this concentration. Under the study conditions, the 28 d EC50 and EC10 values were determined to be at 130 and 70 mg a.i./kg soil ww (i.e., equivalent to 153 and 83 mg a.i./kg soil dw) respectively (van Ginkel, 2004).

Study 2. A study was conducted to determine the toxicity of the read across substance, C12-16 ADBAC (49-51% active in water) to soil microorganisms, according to OECD Guideline 216 and 217, and US EPA OPPTS 850.5100, in compliance with GLP. In this study, the effects of the read across substance on carbon mineralization and nitrogen transformation activity of soil micro-organisms were investigated in two soil types (sandy loam soil and a low humic content sand) by evaluating nitrite, nitrate, ammonium and carbon dioxide formation following 28 d exposure. Fifty grams dry weight of soil samples were mixed with lucerne meal (13:1 carbon:nitrogen) and placed in 100 mL bottles. The samples were incubated in the dark at 20±2°C for 28 d. The moisture content of the samples was checked weekly. The samples were dosed with read across substance at nominal concentrations 0, 10, 100 and 1000 µg a.i./g soil dw. No analytical dose verification was performed for the read across substance. Samples were taken to determine nitrogen metabolite content on days 5 and 28 and the CO2 evolution was determined on Days 5 – 8 and 25 – 28. No significant reduction in ammonium formation was observed. The difference in the CO2 production and nitrogen transformation between the treated and untreated soil samples did not exceed 25% after 28 d of incubation. The highest inhibition recorded was 82.5% in the nitrite formation rate after 5 d at 10 mg a.i./kg soil dw in the sandy loam soil. After 28 d of incubation, however, no relevant effect was observed (<25% reduction). Therefore, it was not necessary to extend the test beyond 28 d. Under the conditions of the study, the read across substance was therefore considered to have a low potential for adversely affecting the microbial functions of sandy loam and low humic content sand soils and the 28 d EC50 and NOEC were considered to be at >1000 and ≥1000 µg a.i./g soil dw respectively (de Vette, 2001).

Based on the above studies, same effect levels and low toxicity potential were concluded in the biocide assessment report on C12-16 ADBAC by RMS Italy. They further stated that: “The studies from the two dossiers, although all rated 1, show marked difference in the results, even when the soil characteristics were similar like in the case of tests conducted with sandy loam soils. The endpoint with the lowest values is therefore selected to be taken into account, i.e., 28d EC50 = 153 mg a.i./kg dw (130 mg/kg wwt soil) and a 28d EC10 = 83 mg a.i./kg dw soil (70 mg a.i./kg ww soil), retrieved from the EQC dossier.”(ECHA biocides assessment report, 2015). Similar conclusions were drawn in the Coco TMAC biocides assessment report, 2016, where the endpoint was mainly assessed based on read across to DDAC along with the EQC owned supporting study on C12-16 ADBAC. The lowest 28d EC50 = 101.3 mg a.s. /kg dw (corrected for MW) and 28d EC10 = 59.3 mg a.s. /kg dw (corrected for MW) from the study on DDAC was selected for risk assessment.

In line with the C12 -16 ADBAC biocides assessment report and gven that the read across to C12-16 ADBAC can be justified for the test substance based on a category approach, the lower 28d EC50 = 153 mg a.i./kg dw and a 28d EC10 = 83 mg a.i./kg dw soil due to inhibition of microorganisms has been considered further for hazard/risk assessment.

Reason / purpose:
data waiving: supporting information
Reference
Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.42 µg/L
Assessment factor:
10
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
0.12 µg/L
Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.042 µg/L
Assessment factor:
1 000
Extrapolation method:
assessment factor
PNEC marine water (intermittent releases):
0.012 µg/L
Hazard assessment conclusion:
PNEC STP
PNEC value:
0.946 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor
Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
6.8 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method
Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.68 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method
Hazard assessment conclusion:
no hazard identified
Hazard assessment conclusion:
PNEC soil
PNEC value:
0.83 mg/kg soil dw
Assessment factor:
100
Extrapolation method:
assessment factor
Hazard assessment conclusion:
no potential for bioaccumulation

Based on the results from the available studies with the test or read across substances, daphnia has been identified to be the most sensitive species. The short-term 48 h EC50 value based on a read across study with Coco TMAC in Daphnia was determined to be 0.012 mg a.i./L (nominal) and the lowest long-term 21-day NOEC value based on a read across study with C12-16 ADBAC in daphnia was at 0.00415 mg/L (measured). Therefore, based on the available results, the test substance C12-18 TMAC warrants a classification as ‘Aquatic Acute 1’ and ‘Aquatic Chronic 1; H410: Very toxic to aquatic life with long-lasting effects’ according to EU CLP criteria (Regulation 1272/2008/EC). M factors to be applied are 10 for acute and 1 for chronic toxicity.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion