Life-history traits of standard and autochthonous cladocerans: I. Acute and chronic effects of acetylsalicylic acid.

Pharmaceuticals have been recognized as an important group of aquatic micropollutants, mainly because of their biologically active nature. Acetylsalicylic acid (ASA), which is the active compound of Aspirin and many other pharmaceuticals, is consumed in large quantities every year. Therefore, its acute and chronic effects on standard (Daphnia magna) and autochthonous (Daphnia longispina) daphnids were investigated. The results showed that ASA impaired the survivorship, reproduction, and growth of the cladoceran species. The standard daphnid was the more tolerant species in acute assays (48-h EC(50) = 1293.05 mg/L; D. longispina: 48-h EC(50) = 647.31 mg/L); whereas the autochthonous daphnid seemed to be more resistant under chronic exposure to ASA, mainly its population-level traits. Despite this, the observed effect concentrations were much higher than the environmental concentrations of ASA. Notwithstanding this, the impairment of individual-level traits is likely to occur at environmental levels as an ultimate response to long-term exposure.