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

Abstract Atorvastatin (ATV) photochemical degradation with radiation relevant to the shortest solar radiation wavelengths reaching the Earth’s surface was studied. Fourteen products of photodegradation (P-ATV) were identified by HPLC-HRMS/MS analysis and for twelve of them, chemical structures were proposed. 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 exposure to P-ATV (IC20 values 140 µg/l and 475 µg/l, resp.). The opposite trend was observed in assays with Daphnia magna where P-ATV were 12 times more toxic than the parent compound (LC50 values obtained for atorvastatin and the photoproduct mixture after 48 h of exposure were 38.5 mg/l and 3.25 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 in comparison to the control group. Neither ATV nor P-ATV affected the interclutch period or the number of clutches. The same trend of higher toxicity of P-ATV was observed in the 96-h test with Danio rerio embryos, where the determined LC50 value for ATV was 5.56 mg/l, while the calculated LC50 value for P-ATV was only 2.74 mg/l. Both groups of embryos of D. rerio (exposed to ATV and P-ATV) showed malformations such as heart oedema and yolk sac oedema with the more pronounced effect being in exposure to P-ATV).