The biodegradability of 2-sulfonatofatty acid methylester (a-SFMe) , an anionic surfactant recently developed for heavy-duty household detergents, was studied by the shake culture method , river die-away test and biochemical oxygen demand measurment method (MITI test). Biodegradation was followed by the methylene blue active substances (MBAS) analysis and/or dissolved organic carbon (DOC), or biochemical oxygen demand (BOD). The biodegradation of a-SFMe was found to start quickly , and then to proceed rapidly to ultimate degradation at sewage treatment plants and in natural river water.

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Effects of 2-sulfonatofatty acid methyl ester (ƒ¿-SFMe) on aquatic organisms and activated sludge were studied. Acute fish toxicity was determined using Japanese killifish (Oryzias latipes) with individual homologues of ƒ¿-SFMe (C12, C14 or C16 alkyl chain length) and C14/C16-mixed ƒ¿-SFMe, according to JIS K 0102 "Testing Methods for Industrial Wastewater-Acute Toxicity Test with Fish". The 96 h lethal concentration fifty (LC50) values for C16-, C14-and C12-ƒ¿-SFMe were 1.3, 24 and 298 mg/L, respectively,

The biodegradation pathways of ƒ¿-SFMe were determined based on changes in the chemical structure of C14-ƒ¿-SFMe by IR, NMR and HPLC analyses in the MITI test. Microbial attack on the surfactant structure was initiated by ƒÖ-oxidation to form a carboxyl group and continued with ƒÀ-oxidation, causing the removal of two carbons at a time, to form a temporary intermediate, monomethyl ƒ¿-sulfosuccinate. Degradation subsequently occurred by desulfonation.

This paper reports the ecotoxicological study of "tetradecanoic acid, 2-sulfo-, 1methylester, sodium salt (C14MES)". This salt was synthesized by sulfonating 1-methyl tetradecanoic acid derived from palm oil and coconut oil with sulfur trioxide. The tests were attempted in accordance with the OECD (Organization for Economic Cooperation and Development) Guidelines for the Testing of Chemicals. The 72 h ErC 50 exceeded 100 mg/L in the alga growth inhibition test. In the daphnia acute immobilization and reproduction tests, 17.2 mg/L of 48 h EC 50 and 4.10 mg/L of NOEC were derived, respectively. These ecotoxicities of C14MES were equivalent to or lower than that of other similar anionic surfactants, such as LAS (linear alkylbenzene sulfonate) or AOS (alpha olefin sulfonate).