Propranolol, a commonly prescribed medication, is often found in wastewater, raising concerns about its impact on aquatic life, particularly in fathead minnows exposed at various developmental stages.
The study measured the fish's transcriptional responses to different concentrations of propranolol over specific timeframes, revealing that older fish (over 7 days post-fertilization) were more sensitive to its effects.
Findings suggest that traditional toxicity testing may underestimate risks since it typically involves younger fish that haven't reached significant developmental milestones, potentially affecting how chemicals like propranolol are understood in terms of environmental impact.