Assessing Caffeine and Linear Alkylbenzene Sulfonate Effects on Molting and Reproduction of Daphnia magna by Quantitative and Qualitative Approaches

Caffeine (CAF) and linear alkylbenzene sulfonate (LAS) are human activity indicators, classified as contaminants of emerging concern (CECs). The long-term effects of these CECs on keystone species are still scarce in the literature. In this study, the molting and reproduction of Daphnia magna were evaluated over chronicle experiments by quantitative and qualitative approaches. The reported environmental concentrations (scenario 1) of CAF (0.005, 0.03, and 0.127 mg L −1 ) and LAS (0.4, 1.0, and 2.5 mg L −1 ) did not show statistical differences in molting process. Inhibition for molting index (%I M ) was observed in expected effect concentration exposures (scenario 2) to CAF (20, 40, and 60 mg L −1 ) and LAS (4.1, 4.5, and 4.9 mg L −1 ). A decrease in the number of offspring (17 to 30%) and anticipation of the release time of the first four broods were observed in exposures to CAF. Moreover, LAS increased the offspring number produced per D. magna in the 1st (33 to 40%) and 2nd (22 to 52%) broods, in addition to a reduction of the time between 2nd and 3rd broods. Evidence of offspring induction in offspring index (%I O ) was observed in exposures to LAS in scenario 1 and inhibition was recorded for scenario 2 (all LAS concentration and 60 mg L −1 of CAF). In scenario 2, for CAF and LAS, caused an inhibition on %I O and a significant decrease in the total offspring produced, especially on the 2nd brood (from 26 to 48%). These findings suggest that the D. magna life cycle may be impacted by a wide range of doses of environmentally relevant pollutants, whereas different approaches support interpreting the level of damage to daphnids’ reproduction and development.