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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Morpholine does not accumulate significantly in organisms

Key value for chemical safety assessment

Additional information

The bioaccumulation potential of morpholine was studied in a flow-through test using Cyprinus carpio as test species for a 6-week exposure (25 °C) period according to the MITI protocol, which corresponds to OECD 305C (NITE, 1980). The BCF at the lower test concentration (0.5 mg/L) was ≤ 2.8 L/kg, while the BCF was lower ≤ 0.3 at the higher test concentration (5 mg/L).

This experimental result is supported with estimation of the BCF using the QSAR estimation model: BCF baseline v4.11 (OASIS CATALOGIC v5.14.1.5). The calculations were performed using experimental data for the water solubility (completely miscible; see IUCLID Ch. 4.8) and the log Kow for the charged (log Kow = -0.88 at pH 7; see IUCLID Ch. 4.7) as well as the uncharged molecule (log Kow = -2.55 at pH 10.3; see IUCLID Ch. 4.7). The results for the charged and the uncharged form are almost identical. The model estimated a BCF of 9.2 L/kg (at pH 7; 9.4 L/kg at pH 10.3) without considering mitigation factors. The model considers several mitigating factors which can reduce the bioconcentration of the substance in aquatic organisms: metabolism, size, water solubility. In case of morpholine, mainly water solubility reduces the  BCF to 3.1 L/kg (pH 7 and pH 10.3) as estimated by the model. The test substance is to 100% within the applicability domain of the model (BASF SE, 2021).

Based on the available experimentally determined BCF and the calculated BCF, it can be concluded that morpholine does not accumulate significantly in organisms.