Date of Award

2018-01-01

Degree Name

Master of Science

Department

Geology

Advisor(s)

Elizabeth J. Walsh

Abstract

Rivers, including the Rio Grande, receive discharges from urban, agricultural, and industrial areas. These discharges have potentially harmful contaminants that may affect life span, fecundity, and/or behaviors of aquatic organisms. In this project, water quality was analyzed near a discharge point source and impacts of pharmaceuticals and personal care products (PPCPs) on a non-target organism (Plationus patulus) were investigated. Long-term and integrative organic samplers (POCIS) were left in situ for about 1 month near a wastewater treatment plant that discharges effluent into the Rio Grande. Over 40 PPCPs, including carbamazepine (ranging from 17.50 to 584.29 ng/L), erythromycin (ranging from 0.51 to 30.15 ng/L), gemfibrozil (ranging from 0.92 to 238.62 ng/L), ofloxacin (ranging from 446.43 to 687.13 ng/L), sulfamethoxazole (ranging from 2.44 to 269.86 ng/L), and trimethoprim (ranging from 0.81 to 118.77 ng/L) were detected in the river. Once PPCPs were identified, four antibiotics were selected to conduct acute (LC50) and chronic toxicity assessments using the riverine rotifer, Plationus patulus. The LC50 for P. patulus exposed to erythromycin for 48h was 39.5 mg/L, 821.8 mg/L for ofloxacin, and 170.3 mg/L for trimethoprim (Probit analysis, p=0.001). These compounds caused negative population growth rates (r) and reduced fecundity (Ro) as well as inhibited egg eclosion and increased egg detachment at sublethal concentrations during chronic exposures. Negative effects similar to those observed during exposures of the three individual PPCPs were seen when P. patulus was exposed to a mixture of them. These results show that wastewater treatment discharges may be a source of PPCP contamination in the Rio Grande and these compounds may have negative effects on the ecology river. Future work should include

determining acute toxicity for the remaining frequently detected compounds and assessing their effects on endpoints such as mortality, reproduction, and swimming behavior. The results of this study give a better understanding of which PPCPs are entering surface waters in the El Paso/Ciudad Juarez stretch of the Rio Grande and how they are potentially affecting aquatic life. Also, these results are contributing evidence that may be used to determine permissible concentrations of PPCPs in wastewater discharges and regulatory guidelines for management of surface waters.

Language

en

Provenance

Received from ProQuest

File Size

162 pages

File Format

application/pdf

Rights Holder

Enrique David Garcia

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