Effects of atorvastatin and its photoproducts on three trophic levels of the aquatic food web

Abstract Atorvastatin (ATV) photodegradation with radiation relevant to the shortest solar radiation wavelengths reaching the Earth’s surface was studied. Fourteen products of atorvastatin photodegradation (P-ATV) were identified by HPLC-HRMS/MS, chemical structures were proposed for twelve of them. The suggested structures include decarboxylated, dehydrated ATV, ether-like structures and phenanthrene-like byproducts. Toxicity assays revealed that exposure to ATV had a greater negative effect on the growth of the green algae Desmodesmus subspicatus than the exposure to P-ATV (IC20 values 140 µg/l and 475 µg/l, resp.). The opposite trend was observed with Daphnia magna where P-ATV was 12 times more toxic than ATV with LC50 values of 3.25 mg/l and 38.5 mg/l, resp.). Long-term exposure to environmental concentrations showed that P-ATV significantly lowered the number of juveniles of D. magna , while ATV had no effect. Neither ATV nor P-ATV affected the interclutch period or the number of clutches. The higher toxicity of P-ATV was observed also in the 96-h test with Danio rerio embryos (the determined LC50 values for ATV and P-ATV 5.56 mg/l and 2.74 mg/l, resp.). Both groups of embryos of D. rerio (exposed to ATV or P-ATV) showed malformations such as heart and yolk sac oedema with the more pronounced effect in P-ATV. The novelty of the study is in a significant contribution to the understanding of the photochemical degradation of atorvastatin under UV light conditions relevant to surface waters together with the demonstration of deleterious effects of photoproduct mixture on the selected aquatic organisms of different trophic levels. Graphical abstract