For waste management in Asunción, Paraguay to improve, so too must the rate of public recycling participation. However, due to minimal public waste management infrastructure, it is up to individual citizens and the private sector to develop recycling solutions in the city. One social enterprise called Soluciones Ecológicas (SE) has deployed a system of drop-off recycling stations called ecopuntos, which allow residents to deposit their paper and cardboard, plastic, and aluminum. For SE to maximize the use of its ecopuntos, it must understand the perceived barriers to, and benefits of, their use. To identify these barriers and benefits, a doer on-doer survey based on the behavioral determinants outlined in the Designing for Behavior Change Framework was distributed among Asunción residents. Results showed that perceived self-efficacy, perceived social norms, and perceived positive consequences – as well as age – were influential in shaping ecopunto use. Other determinants such as perceived negative consequences, access, and universal motivators were significant predictors of gender and age. SE and other institutions looking to improve recycling can use these results to design effective behavior change interventions.

The threat of global climate change to the world’s water resources has jeopardized access to clean drinking water across the world and continues to devastate biodiversity and natural life globally. South Africa operates as a useful case study to understand and analyze the effectiveness of public policy responses to the perils of climate change on issues of water access and ecosystem preservation. After the new South African Constitution was enacted in 1997, protecting water resources and ensuring their equitable distribution across the nation’s population was a paramount goal of the young democratic government. The National Water Act was passed in 1998, nationalizing the country’s water infrastructure and putting in place programs seeking to ensure equitable distributive and environmental outcomes. Thus far, it has failed. Access to South Africa’s water resources is as stratified as access to its economy; its aquatic ecosystems remain in grave danger; and many of the same problems of South Africa’s Apartheid era still plague its efforts to create an equitable water system. Decision-making power continues to be concentrated in the hands of the wealthy, at the expense of historically marginalized groups, whose voices are still not adequately heard. Corporate actors still exert undue influence over legislative policy that favors economic growth over environmental sustainability. The looming threat of climate change is exponentially increasing the chances of disasters like Cape Town’s 2018 feared ‘Day Zero’. The National Water Act’s noble intentions were never actualized, and therefore the people of South Africa remain in serious danger of acute and chronic threats to their water supply.

The integration of Urban Ecological Infrastructure (UEI) has gained attention as cities seek to address challenges posed by urbanization. Constructed treatment wetlands (CTWs), commonly used for removing pollutants from wastewater effluent and storm water runoff, have been proposed as a solution to address challenges posed by rising water challenges. CTWs serve as a unique type of UEI and provide a range of ecosystem services in urban landscapes. With current global concerns over water scarcity and sustainable resource management, wetlands emerge as key components, providing vital ecosystem services, one of which is nutrient filtration. Nitrogen pollution in water bodies poses significant environmental and public health concerns, emphasizing the need for effective mitigation strategies. CTWs present a promising solution for addressing nitrogen pollution in urban settings. However, there are gaps in understanding wetland functioning within arid environments, necessitating arid climate studies to explain nitrogen dynamics. This study, conducted in the Tres Rios Wetland in Phoenix, Arizona, aims to examine nitrogen content in soils. Soil nitrogen content trends from 2019 to 2023 were investigated, with a focus on understanding nitrogen dynamics from inflow to outflow points and comparison from water to shore. There were no trends seen in nitrogen content over time from 2019 to 2023. Additionally, nitrogen levels tended to be higher at the shorelines compared to the open water, likely due to the accumulation of organic matter and soil nitrogen absorption. However, there were no trends observed in nitrogen content from the inflow to outflow points.

Plasticizers are plastic additives used to enhance the physical properties of plastic and are ubiquitous in the environment. A class of plasticizer compounds called phthalate esters that are not fully eliminated in wastewater treatment facilities are relevant to the ecological health of downstream ecosystems and urban areas due to their ecotoxicity, tendency for soil accumulation, and the emerging concern about their effects on public health. However, plasticizer concentrations in a constructed wetland environment have rarely been studied in the United States, prompting the need for a method of plasticizer quantification in the Tres Rios Constructed Wetlands which are sustained by the effluent of the 91st Avenue Wastewater Treatment Plant in Phoenix, Arizona. The concentrations of four common plasticizer compounds (dimethyl: DMP, diethyl: DEP, di-n-butyl: DnBP, and bis(2-ethylhexyl): DEHP phthalate) at five sites across the wetland surface water were quantified using solid-phase extraction followed by gas chromatography coupled with mass spectrometry (GC/MS). The sampling period included four sample sets taken from March 2022 to September 2022, which gave temporal data in addition to spatial concentration data. Quantification and quality control were performed using internal standard calibration, replicate samples, and laboratory blanks. Higher molecular weight phthalates accumulated in the wetland surface water at significantly higher average concentrations than those of lower molecular weight at a 95% confidence level, ranging from 8 ng/L to 7349 ng/L and 4 ng/L to 27876 ng/L for DnBP and DEHP, respectively. Concentrations for dimethyl phthalate and diethyl phthalate were typically less than 50 ng/L and were often below the method detection limit. Average concentrations of DnBP and DEHP were significantly higher during periods of high temperatures and arid conditions. The spatial distribution of phthalates was analyzed. Most importantly, a method for successful ultra-trace quantification of plasticizers at Tres Rios was established. These results confirm the presence of plasticizers at Tres Rios and a significant seasonal increase in their surface water concentrations. The developed analytical procedure provides a solid foundation for the Wetlands Environmental Ecology Lab at ASU to further investigate plasticizers and contaminants of emerging concern and determine their ultimate fate through volatilization, sorption, photodegradation, hydrolysis, microbial biodegradation, and phytoremediation studies.

Humans can influence wildlife populations and behavior through structural and behavioral disturbances, which can be particularly pronounced along the gradient of urbanization. Importantly, although anthropogenetic structural characteristics are relatively static along the gradient of urbanization for a given period of time, the presence of humans can be dynamic on daily and seasonal scales, which can affect wildlife activity patterns. The rapid onset of the COVID-19 pandemic created a unique opportunity to evaluate how a sudden change in human behavior can affect wildlife activity along the urbanization gradient. Specifically, we used a before-after-control-impact (BACI) study design to compare human presence and coyote daily activity patterns from before the COVID-19 pandemic to after COVID-19 stay-at-home orders and shutdowns were put in place in areas of low and high levels of urbanization. We predicted that human detection rates would increase in low levels of urbanization and decrease in high levels of urbanization due to the COVID-19 pandemic shutdowns. We also predicted that coyote daily activity patterns would shift in response to human detection rates, where coyotes would become more nocturnal in areas of low levels of urbanization where human presence was expected to increase and become more diurnal in areas of high levels of urbanization where human presence was expected to decrease. We used data from wildlife cameras across the gradient of urbanization from 2019 to 2020 within the Phoenix Valley of Arizona. Across 8 sites in low levels of urbanization and 12 sites in high levels of urbanization, we did not find a statistical difference in human detection rates or coyote activity patterns in response to the COVID-19 pandemic. However, low sample size likely led to low power to detect differences and next steps for this research (as part of my M.S. thesis project) will be incorporating additional wildlife camera locations and wildlife species (e.g., bobcat, cottontail rabbit, gray fox, etc.), into future analyses. This project and future studies can help us better understand how structural and behavioral characteristics of humans can shape wildlife populations along the gradient of urbanization, which has important conservation implications for wildlife and people.