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

Endpoint summary

Description of key information

Under the conditions of the tests presented and based on their results, N,N-Didecyl-N-methylpoly(oxyethly)ammonium Propionate can be considered to be hydrolytically stable at 25°C at pH 4, 7 and 9 for over 1 year.

The phototransformation study has been conducted with the chemical and structural analog, Didecyldimethylammonium Chloride (DDAC). DDAC is photolytically stable in absence of a photosensitising agent. Based on the close similarities of this structural analog, didecylmethylpoly(oxyethyl)ammonium propionate is expected to undergo comparable phototransformation in water.

Ready Biodegradability:

The key study was carried out in accordance with OECD Guideline 301B.

The ready biodegradability of¹⁴C-N,N-didecyl–N-methyl-poly(oxyethyl)ammonium propionate, dosed at 0.2 mg/L, was determined in a ready biodegradability study conducted according to OECD Guideline 301B. The mean cumulative¹⁴CO₂production was equivalent to 10% after 4 days and progressed rapidly until Day 8. The rate of biodegradation then slowed. 34% biodegradation had occurred by the end of the study, but was less than the 60% required to qualify for classification as readily biodegradable. Under the strict terms and conditions of the OECD Test Guidelines for ready biodegradability N,N-didecyl–N-methyl-poly(oxyethyl)ammonium propionate cannot be termed readily biodegradable.

A supporting study was carried out according to the same procedure (OECD Guideline 301B, CO2 Evolution Test), with non radio-labelled test substance dosed at a concentration of 5 mg C-equivalent/L. Didecyldimethylpoly(oxyethyl) ammonium propionate showed 0% degradation at the end of the incubation, confirming the indication of the key study, i.e. that the test substance is not readily biodegradable. There was no evidence of interference due microbial inhibition in the toxicity control included in the study design (the test substance caused no significant suppression of the degradation of the reference substance) and a subsequent (non-standard) toxicity check showed no evidence of microbicidal activity based on total viable counts of the inoculum after exposure to the same concentration of didecyldimethylpoly(oxyethyl) ammonium propionate under incubation conditions identical to those of the biodegradability assessment.

Inherent biodegradability:

In a further supporting study, the behaviour of Didecyldimethylpoly(oxyethyl)ammonium Propionate

was investigated according to OECD Guideline 302B (Zahn-Wellens Test). Activated sludge suspended in a standard mineral salts medium was dosed with Didecyldimethylpoly(oxyethyl)ammonium propionate at 303 mg C-equivalent/L. It should be noted that this concentration considerably exceeds the 3 -hour EC50 for the inhibition of respiration of activated sludge microorganisms and toxicity may have influenced the outcome of the study. Based on the measured DOC concentrations in samples taken after 3h and on days 1, 7, 10, 15, 20 and 28, the % elimination and % biodegradation was calculated after correction for the corresponding blank values.

53% elimination was observed after 3h, indicating a high degree of adsorption. Elimination of didecyldimethylpoly(oxyethyl)ammonium propionate reached 80% after 28 days, representing the combined effects of physico-chemical elimination and biodegradation processes (23% and 57%, respectively). Didecyldimethylpoly(oxyethyl)ammonium propionate removal between the untreated influent and the treated effluent due to the combined effects of abiotic and biological processes was expected to exceed 50% in industrial waste water treatment works.

Biodegradation in soil:

An initial aerobic degradation study in soil and additional soil degradation studies are not required.

Bioconcentration:

In a study conducted in accordance with U.S.EPA Guideline 165-4 (1989), Bluegill fish (Lepomis macrochirus) was exposed to the test material, Bardac 22 with radiolabelled Didecyldimethylammonium Chloride at concentrations of 0, 59.0 µg/l (actual concentration - 93 ± 32 µg/l). 220 bluegill were tested at each concentration. The test organisms were exposed to the test material in aquaria for 28 days, with an 18 day depuration period. Fish were collected on days 4, 10, 17, 24 and 28 of the exposure and on days 3, 7, 14 and 18 of depuration. Tissues from control fish were sampled on days 0 and 28 of exposure and day 18 of depuration. On day 28 of exposure, an additional five fish were sampled and divided into three tissue portions; edible (fillets), non-edible (head, fins and viscera) and skin. Edible tissues from each of three sets of approximately 10 fish sampled on day 28 were subjected to hexane/methanol tissue extraction, combusted and then counted to quantify that portion of the¹⁴C-residue not extractable with either solvent. Five treated fish died during the exposure test and no fish died during depuration. Under the conditions of this study, for edible tissue, the BCF was 38 (predicted 52) and elimination after 14 and 18 Days was 57% and 38%, respectively. For non-edible tissue, the BCF was 140 (predicted 160) and elimination after 14 and 18 Days was 71% and 66%, respectively. For whole-body, the BCF was 81 (predicted 95) and elimination after 14 and 18 Days was 67% and 56%, respectively. In conclusion, skin tissue showed¹⁴C-residues 2 to 6 times higher than edible tissue portions. The test substance may bind significantly to skin and scales of exposed fish. Of the accumulated¹⁴C-residue in the edible tissue of bluegill exposed 28 days to the test substance, 65.5% was extractable with a polar solvent (methanol), 8.1% was extractable with a nonpolar solvent (hexane) and 25.9% was not extractable with either solvent. Based on measured BCF values, didecylmethylammonium chloride has only a modest bioconcentration tendency and the same may be expected for N,N-didecyl-N-methyl-poly(oxyethyl)ammonium propionate.

Mobility in soil:

An adequate study has been conducted on the chemical and structural analog, Didecyldimethylammonium Chloride. In view of the chemical and structural similarities, it is considered that the available data is adequate for N,N-Didecyl-N-methyl-poly(oxyethyl)ammonium Propionate.

Didecyldimethylammonium Chloride was classified as immobile in four soil/sediment types with the adsorption (K_d) and mobility (K_oc) coefficients of K_d=1,095 and K_oc=437,805 for sand, K_d=8,179 and K_oc=908,757 for sandy loam, K_d=32,791 and K_oc=1,599,564 for clay loam, and K_d=30,851 and K_oc=1,469,081 for silt loam (Ref No 1792).

The results of the adsorption in soil study on a structural analog Didecyldimethylammonium chloride indicate little or no potential for mobility in soil and should not pose an environmental risk for contamination of ground water.