Impact of acetaminophen and microplastic exposure on Physa acuta movement, growth, and reproduction

Pharmaceuticals and plastics are frequently detected in aquatic ecosystems because of their increasing production and use. Pharmaceuticals, such as acetaminophen, enter freshwater ecosystems through non-point sources and from hospital and wastewater treatment plants effluent. Microplastics are plastic particles smaller than 5 mm that form from the breakdown of plastic often from consumer products and packaging materials. This study examines the effects of individual and combined acetaminophen and microplastics on the aquatic snail Physa acuta. Over a 14-day period, we measured snail growth, movement, and reproductive outputs (i.e., number of egg clusters and total number of eggs). Our results showed that snail movement decreased when exposed to acetaminophen and increased when exposed to microplastics, with these two treatments significantly different from each other (p = 0.017). The total number of eggs decreased when exposed to individual and combined acetaminophen and microplastics (p < 0.001). Overall, acetaminophen effects were likely as result of oxidative stress and neurotoxicity, while microplastics affected the digestive system. Both impair energy acquisition and reserves thus decreasing available energy for movement and reproduction. These changes in snail fitness have the potential to alter food webs, nutrient cycles, and biodiversity. Our findings highlight the need for research on pharmaceuticals and microplastics to better understand their long-term ecological impacts.