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Melissa Rivera-López

Doctoral Degree Student

Graduate Program: Anatomy & Neurobiology

Thesis Title: The effects of Atrazine on locomotion and anxiety-like behavior in a terrestrial mammalian model

Background: Chemical exposure, such as ingestion of an herbicide, can disrupt brain function (Tanner et al., 2011) and impair emotionally-relevant behaviors in rodents (Walters et al., 2016). In support of this, ingestion of the herbicide Atrazine in high doses, impairs emotions in rodents (Walters et al., 2016; Ma et al., 2018; Chávez-Pichardo et al., 2020). However, the effects of Atrazine ingested at levels thought to be safe according to the EPA (U.S. Environmental Protection Agency: Chemical Assessment Summary, 1993) are largely unexplored. Therefore, we aim to examine how exposure to “safe” levels of Atrazine may affect locomotion and anxiety-like behavior in rats.


Catalina Rodriguez Alemany

Ph.D. Student

Biology Graduate Program

Thesis Title: The neurophysiological, neuroendocrine, and behavioral effects of chemical stressors on the Western honey bee’s (Apis mellifera L.) nervous system

Background: Honey bees (Apis mellifera L.) are economically and ecologically important plant pollinators in agricultural and non-agricultural landscapes that are highly and constantly exposed to diverse abiotic and biotic environmental stressors such as chemical pollutants. Over the past decades, stressors have been linked as the source of honey bee colony losses and the decline of wild bee populations. Stressors’ impact bee’s individual and social homeostasis by affecting bee’s behavior and disrupt bee’s brain function and cognitive abilities. To assess the effects of chemical pollution on the Western honey bees’ neurobiology throughout development, two ubiquitous chemical pollutants - aluminum and phthalates - that have been detected in bee products and tissues were selected. Research on bees may develop this organism as a bioindicator of environmental pollution for other terrestrial organisms.


Stefani M. Cruz Rosa, MHSN

Ph.D Candidate

Environmental Sciences Department, University of Puerto Rico, Rio Piedras

Dissertation Title: Titanium Oxide nano-particles pollution in freshwater ecosystem: Atya lanipes shrimp as a neurotoxic model

Background: I specialize in emerging pollutants such as nanoparticles of Titanium Oxides and I evaluate the possible neurotoxic impact that they can have on the freshwater biota. My study organism is Atya lanipes shrimp which is an endemic shrimp to the rivers in Puerto Rico. This shrimp has a very important ecological role in the freshwater ecosystem since it promotes water quality, sediment restoration and is one of the first organism in the food web (many organisms feed on it). The purpose of my project is to understand how titanium oxide nanoparticles, which are widely used in sunscreen, cosmetics, lotions, as food additives and household materials such as primers, paints, etc., can affect this shrimp in the first few larval stages and in adulthood at the neurotoxic level. This project is very important in terms of gathering data that can eventually be used in the process of regulating these pollutants for the conservation of the freshwater ecosystem.

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Marla V. Santos

Doctoral Student

Environmental Sciences Department, University of Puerto Rico, Rio Piedras

Dissertation Title: Evaluation of the effect of different land-use histories on the population biology and individual exposure to insecticides of the freshwater shredder shrimp Xiphocaris elongata

Background: ¡Hola! I'm a freshwater ecologist in training, interested in freshwater shrimp population dynamics and their neuro-ecotoxicology. As a Ph. D. student in the Department of Environmental Sciences of the Universidad de Puerto Rico, Río Piedras Campus, my thesis project is titled "Evaluation of the effect of different land-use histories on the population biology and individual exposure to pesticides of the freshwater shredder shrimp Xiphocaris elongata". This body of work looks into the effect that rural, urban, and agricultural development around three Puerto Rican streams can have in the sex ratio, density, and fecundity of X. elongata, while describing their water quality and pesticide residues present. Secondly, the description of the changes in behavior of adult and juvenile individuals of X. elongata exposed to a series of concentrations of two neonicotinoid insecticides, thiamethoxam and imidacloprid. Data compiled is evaluated from behavioral (locomotion and response to predators) and neurological (immunohistochemistry of neurons) perspectives. Additionally, a series of conferences and seminars are directed to the general public and all kinds of schools. The intention is to share our knowledge in environmental neurosciences and transmit it to younger generations. If interested in the project, or have any other inquiry, you may contact me via

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