Effects of pharmaceuticals on the reproduction of aquatic organisms: a meta-analysis

Trabalho de projecto de mestrado, Bioestatística, Universidade de Lisboa, Faculdade de Ciências, 2019Pharmaceutical compounds have been discharged into the environment for as long as they have been produced. Many of these pharmaceuticals can disperse directly into the environment or through sewage plants, contaminating rivers, estuaries and interacting with non-target organisms. Though their concentrations in the aquatic environment are often low, these drugs are designed to produce biological effects at low concentrations, targeting specific metabolic pathways. Though research on the impacts of pharmaceuticals in aquatic organisms is growing substantially, we still lack clear understanding on the topic. This study aims to provide quantitative insight on the effects of antidepressants in the reproduction of fish and crustaceans. To address this, multilevel meta-analysis was performed. It consisted of 19 studies from research literature investigating effects of antidepressant exposure in fish or crustaceans’ reproduction according to specific selection criteria. Following standard procedures used in meta-analytic studies, heterogeneity analysis was performed and the moderating effect of concentration, exposure time, organism group and toxicant was tested. Additionally, publication bias was also addressed. The results showed that, overall, there is no significant association between antidepressant exposure and the reproduction of fish and crustaceans. Moderator analysis revealed, however, that concentration is a significant moderator for fish and crustatea fecundity. Fish and crustatea showed contrary results when accounting for this moderator. The former had a small, yet positive effect (g=0:368), meaning that increased concentrations result in increased fish fecundity, and the latter a negative, in magnitude slightly larger, effect (g = 0:453), meaning a decrease in crustaceans’ fecundity with a concentration rise. These findings help us understand that though antidepressants can have effects on reproductive outcomes in aquatic organisms, as narrative reviews address, other factors can have an important role. In spite of this, more research on the subject is need since meta-analysis are only as statistically powerful as the number of studies they include