12/07/2023
By Danielle Fretwell

The Francis College of Engineering, Department of Civil and Environmental Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Gustavo Salcedo on: Occurrence, Distribution, and Ecological Impacts of Drugs of Abuse in Aquatic Environments.

Candidate Name: Gustavo Salcedo
Degree: Doctoral
Defense Date: Monday, Dec. 18, 2023
Time: 10 a.m. to noon
Location: Perry 415

Committee:

  • Advisor: Sheree Pagsuyoin, Associate Professor, Civil & Environmental Engineering, UMass Lowell
  • Arghavan Louhghalam, Associate Professor, Civil & Environmental Engineering, UMass Lowell
  • Frédéric Chain, Associate Professor, Biological Sciences, UMass Lowell
  • Marta Gomez-Chiarri, Professor, Fisheries, Animal and Veterinary Sciences, URI

Brief Abstract:

Drugs of abuse are considered as emerging micropollutants (i.e., pollutants at parts per billion levels and below) of concern due to their increasing global consumption, incomplete removal during wastewater treatment, and continuous discharge to streams. They are highly psychoactive compounds, and many have been shown to be highly persistent in the environment. While the aquatic ecotoxicities of other micropollutants such as estrogens and antibiotics have been well studied, the impacts of drugs of abuse on aquatic organisms are poorly understood. There is a need to establish the ecological risks associated with residual drugs discharges in aquatic ecosystems.

The over-all goal of this research is to evaluate the environmental distribution and impacts of drugs of abuse in aquatic ecosystems. The study will be divided into three components: (i) examination of the distribution of drugs in surface waters (ii) ecotoxicity studies to assess impacts on growth and development of aquatic organisms, and (iii) evaluation of the environmental risks of drug discharges. Local environmental drug occurrence and distribution will be established through a through a field sampling campaign in four major urban rivers in Massachusetts (local distribution): Merrimack River, Blackstone River, Connecticut River, and Charles River. Additional sampling will be performed along the coasts of Massachusetts Bay in areas impacted by effluent discharges and combined sewer overflows. Ecotoxicity exposure tests on oyster larvae will evaluate drug exposure effects on the growth, survival, and induction of stress biomarkers (via transcriptomic analysis). Additionally, ecotoxicity tests on Daphnia magna will evaluate effects on mortality. An environmental risk rating scale, ranging from 0-1, will be developed to rank the relative ecological risks of residual drugs discharged to the environment. The index will be based on the median lethal dose concentrations (LC50) determined from the ecotoxicity tests. The findings of this study will provide insights on the distribution of drugs in aquatic ecosystems and contribute to our understanding of the ecological risks associated with drug discharges.