Print PagePharmaceutical and Personal Care Products (PPCPs) are chemicals of emerging concern that have been detected in many of our nation’s waterways. The Rio Grande is the main source for drinking and irrigation water to many parts of the United States and to Mexico, especially the El Paso/Ciudad Juárez metroplex. The river receives pollutants from industrial, urban and agricultural uses that potentially affect the aquatic system but little is known about PPCPs in the Rio Grande and even less is understood about their impacts on aquatic life. We are using rotifer Plationus patulus, a basal member of aquatic food webs, to test for potential acute and chronic toxicity of 4 selected PPCPs (caffeine, triclosan, acetamidophenol, sulfamethazine). Two populations of P. patulus were tested, one from a highly impacted site (Rio Grande, downstream El Paso, TX) and the other from a remote site near Big Bend National Park, TX.
Results/Conclusions
For P. patulus at the unimpacted site, the 48 hr caffeine LC50 was 425 mg/L which was slightly lower than values reported for Daphnia magna, an EPA aquatic indicator species. The LC50 for acetamidophenol is 25 mg/L which is also lower than Daphnia magna (LC50 = 40.8 mg/L); thus P. patulus is more susceptible to these PPCPs and may represent a more sensitive bioindicator for these compounds. Chronic toxicity was assessed using a modified life cycle test in which the population growth rate was calculated over a range of concentrations of caffeine. For the unimpacted population, this resulted in a significant decline in population growth with an increase in caffeine concentration. After 5 days there was a significant decrease in population growth rate (r) between the control (0.23 ± 0.02), 100ppm and 200ppm (0.06 ± 0.012), and 300ppm (-0.08). Preliminary range finder tests show that P. patulus from the impacted site have a higher tolerance for caffeine (LC50, 600 mg/L). Replicate tests will be conducted for the remaining three PPCPs. Results for these experiments will provide insight into how these compouns may impact aquatic invertebrate communities and provide data for resource managers to more effectively protect our water resources.
