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Environmental fate & pathways

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A ‘ready’ biodegradability (modified Sturm test) was conducted with di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA). Since di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) was not sufficiently soluble to allow preparation of an aqueous solution at a concentration of 1 g/l, weighed amounts were added to the 2-litres test bottles containing medium with microbial organisms and mineral components. The relative biodegradation values calculated from the measurements performed during the test period revealed 14 and 17% biodegradation of di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA), for the duplicate bottles tested. In conclusion, di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) was designated as not readily biodegradable.

An inherent biodegradation study was conducted withdi C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) in sealed vessels with headspace test analysis of C02. Since, di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) was poorly soluble in water, 3.2 mg test substance,corresponding toa final organic carbon concentration of 20 mg C/l, was added directly to the test medium (final volume bottle 107 ml). The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA).

In conclusion, di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) is designated as not inherently biodegradable.

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