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Environmental fate & pathways

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Although TMQ is not readily biodegradable and also not inherently biodegradable with nearly no degradation observed up to 35 days, it is abiotically unstable in aquatic environment with a hydrolysis half-life of 16 hours at 23°C and a half-life of direct phototransformation in water of less than 3 minutes. However, these abiotic degradations are of less relevance, since TMQ as a mixture of oligomer derivatives is mostly insoluble TMQ is bioaccumulative with an experimentally determined BCF up to 1300. Simultaneously, TMQ has a high adsorption potential in soil/sludge with the adsorption coefficient (log Koc) mostly above 4.09. TMQ is essentially non-volatile with the estimated Henry's law constant in the range of 2.8*10-9 to 3.0*10-5 Pa*m3/mol at ambient temperature using TMQ-dimer and trimer as typical compositions. The half-life in air of TMQ-dimer and trimer was estimated to be 1.5-2.0 hours which is much shorter than 48 hours and hence no potential for long-range transport of TMQ in air is expected. As a mixture of oligomer derivatives of 1,2-Dihydro-2,2,4-trimethylquinoline with diverse physico-chemical properties, generic distribution is hardly to be modeled. However, considering the low water solubility observed (< 1 mg/l at 20°C), the low vapour pressure (<< 1 Pa), and relatively high Log Pow (5.8 in average) and Log Koc (mostly above 4.09), the TMQ released into environment is expected to be mostly found in sediment and soil compartment.