Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

Endpoint summary

Description of key information

Terrestrial toxicity endpoints are available for three trophic levels: producers (higher plants), consumers (earthworms) and decomposers (soil microorganisms). The studies for higher plants and decomposers were conducted with Bardac 22 (DDAC), a structural analog surrogate for Bardap 26.

The plant study addressed the short-term effects on emergence and seedling development in soil treated with DDAC. No significant impact on germination was observed. Treatment related effects were observed in relation to seedling development, with the lowest EC₅₀found to be 283 mg/kg dry soil for mustard (Brassica alba).

The key study for acute toxicity to earthworms (Eisenia foetida) found that the 14-day LC₅₀for Bardap 26 exceeded 1000 mg/kg dry artificial soil. In a further earthworm study it was estimated that the 14-day LC₅₀was 4390 mg/kg dry artificial soil, and the NOEC was 2000 mg/kg dry artificial soil.

In the study of the effects of Bardac 22 (DDAC) on the activity of indigenous microbial communities, no significant inhibition effects were found for either the mineralization of organic carbon, or the transformation of nitrogen.The NOECS determined in this 28 day study were greater than 1000 mg/kg dry soil for both carbon and nitrogen transformation processes. It is also important to note that many distinct groups of organisms are involved in nitrogen transformation, and that the results obtained show that none of these groups are affected by DDAC on a long-term basis.

Based on these studies, terrestrial plants emerge as the most sensitive group of soil organisms, with seedling growth being the most impacted measured parameter.

Toxicity to small macroorganisms except arthropods:

In a study conducted in accordance with OECD Guideline 207 and Directive 88/302/EEC, Part C, earthworms (Eiseniafoetidafoetida) were exposed to the test substance, N,N-Didecyl-N-methyl-poly(oxyethyl)ammonium Propionate at concentrations of 0, 95, 171, 309, 556 and 1000 mg/kg soil.The test was conducted in labelled one-litre glass containers and groups of forty worms were allocated to artificial soil containing one of the test concentrations.Worms were removed and counted on days 7 and 14. Worms were replaced in the soil on day 7. There was a single mortality in test group 95 mg/kg but this was considered to be unrelated to treatment. There were no adverse effects observed on body weight, morphological observations or behavioural observations. Under the conditions of the test, the LC₅₀value was determined to be greater than 1000 mg/kg, the highest level tested. The test substance had no effect on mortality and body weights, under the conditions of this study.

Toxicity to terrestrial plants:

In a study conducted in accordance with OECD Guideline 208, Mustard (Brassica alba), Mung bean(Phaseolus aureus) and Wheat (Triticum aestivum) were exposed to the test substance, Bardac 22 at concentrations of 100, 200, 400, 800 and 1600 mg/kg for a period of 19 - 20 days. Groups of 40 seeds (eight replicate pots of five seeds) were sown into a garden loam soil treated with Barquat MB 50 (ADBAC), with controls also included. The Bardac 22 was prepared in a 100 mL volume of reverse osmosis water for each species at each rate of application. This was then thoroughly mixed into the soil. A further 50 mL of water was then added to produce a soil structure suitable for sowing.

After application and sowing the pots were checked daily and emergence recorded. Growth inhibition, mortality and other symptoms were recorded at least every other day following 50% emergence in the control pots. Plants were harvested 14 - 16 days after germination by cutting each stem at soil level. The wet weight of each plant was then recorded. The plants were then dried before being re-weighed to obtain a measurement of dry weight.

The test substance had no significant effect on the number of germinated plants for any species.

For mustard, all concentrations of the test substance significantly reduced both wet and dry weight. For wheat, the test substance at 400 mg/kg and higher gave a significant reduction for both dry weight and wet weight. For mung bean, at 320 mg/kg and higher gave a significant reduction for both wet and dry weight. 

The EC₅₀for mustard seeds was determined to be 283 mg/kg (dry weight), for wheat, the EC₅₀was determined to be 857 mg/kg (dry weight) and for mung beans, the EC₅₀was determined to be 1670 mg/kg (dry weight). The results of the study indicate that Didecyldimethylammonium Chloride is slightly toxic to terrestrial plants.

Toxicity to soil microorganisms:

In a study conducted in accordance with OECD Guidelines 216 and 217, 50 g samples of low humic content sand and sandy loam were treated with Didecyldimethylammonium Chloride at concentrations of 0, 10, 100 and 1000 mg/kg dry weight soil and incubated in the dark at 20°C for 28 days. Samples were taken to determine nitrogen metabolite content on days 5 and 28. CO₂evolution was determined on days 5 – 8 and 25 – 28. Didecyldimethylammonium Chloride can be characterised as having no long-term influence on nitrogen or carbon transformations in soils. The test substance had no effect on the production of nitrates, nitrites and carbon dioxide.

Toxicity to birds:

In a study conducted in accordance with US EPA FIFRA Guideline 71-1, Northern Bobwhite (Colinus virginianus)were exposed to the test material, N,N-Didecyl-N-methyl-poly(oxyethyl)ammonium Propionate (Bardap 26), for 21 days, at concentrations of 0, 28, 47, 78, 130, 216, 360 and 600 mg/kg. A vehicle control of deionised water was also used. Male and female test animals were used, with 10 animals (5 males and 5 females) per test concentration and vehicle control. Mortality and signs of clinical toxicity were observed twice daily and bodyweight and estimated feed consumption were measured on Days 0, 3, 7 and 14 and 21 of the test. Under the conditions of this study, the acute oral LD₅₀for Northern bobwhite was found to be 226 mg/kg. Lesions observed at necropsy, primarily associated with necrosis in the esophagus and crop, would indicate a “point of entry” effect of the test substance. Based on the results of this study, the LD₅₀for Northern bobwhite was found to be 226 mg/kg and the no mortality level was 78 mg/kg.