Behaviour of pharmaceuticals in spiked lake sediments – Effects and interactions with benthic invertebrates

The behaviour and effects of atorvastatin (ATO), carbamazepine (CBZ), and 17α-ethinylestradiol (EE2) were investigated in spiked lake sediments, at concentrations up to 56.5 mg kg−1 dry weight (dw), with the benthic invertebrates Chironomus dilutus and Hyalella azteca. Desorption constants were calculated in the presence and absence of animals, using linear isotherms, yielding Kd values of 28.2, 189.0 and 125.1 L kg−1 (ATO), 73.7, 201.7 and 263.2 L kg−1 (CBZ), and 114.9, 114.2 and 519.2 L kg−1 (EE2) for C. dilutus, H. azteca, and without animals, respectively. For ATO and CBZ, Kd values were smaller in the presence of C. dilutus, indicating greater desorption to the overlying water from bioturbation, which is consistent with the predominantly benthic occurrence of C. dilutus compared to H. azteca. In contrast, due to its greater hydrophobicity, bioturbation did not significantly affect desorption of EE2. No significant toxicity was observed, indicating decreased bioavailability of the chemicals sorbed to sediments compared with water-only toxicity assays.

► We examined the behaviour and effects of three pharmaceuticals in lake sediments.
► We calculated desorption constants with and without benthic invertebrates present.
► ATO and CBZ had smaller desorption constants with C. dilutus due to bioturbation.
► Desorption of EE2 was unaffected due to its greater hydrophobicity.
► No toxicity was observed, reflecting decreased bioavailability in sediments.