In a new study published in the Science Advances journal, the University of Florida Institute of Food and Agricultural Sciences, researchers say they have found a better way to assess the potential impacts of low doses of man-made chemicals – like pharmaceuticals and personal care products (PPCPs) – on water bodies and their ecosystems. PPCPS are widely released into the world’s freshwaters and oceans, where they mix at low concentrations over long time periods and seep into diverse environmental pathways such as surface water, groundwater, drinking water, or soil.
“The end effect could be degradation of aquatic life,” said Rafael Muñoz-Carpena, a UF/IFAS professor of agricultural and biological engineering and a lead author of a new UF/IFAS-led study. “Some pharmaceuticals that individually are typically not toxic at even high doses, can damage aquatic life at very low doses when present in complex mixtures often found in natural waters after wastewater finds its way there.” Most PPCPs have been found and analyzed in high concentrations individually, but a new test developed by the UF/IFAS-led team detects the effects of the chemicals in low-dose mixtures.
In the study, the team tested their method in a freshwater environment that they created in their lab. They selected PPCPs including antibiotics, caffeine, analgesics and psychiatric drugs. Researchers then mixed those 16 chemicals with blue algae engineered to produce light. They used changes in the light signal to gauge the toxicity of the different mixtures of chemicals in the bacteria.
Scientists found that a handful of the PPCPs in the mixtures, particularly antibiotics and other commonly used medicines, may impede processes such as growth, assimilation of nutrients, photosynthesis, reproduction and more. Results confirm that PPCP mixtures make freshwater ecosystems more susceptible to stresses such as light, temperature, nutrient availability and competition with other organisms.