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Comparing the utility of wastewater tracers between temperate and tropical coastal urbanized embayments
Citation:
Katz, D., J. Sullivan, I. Cappiello-Cosme, Alana Hanson, M. Molina, E. Huertas, M. Schwartz, AND A. Oczkowski. Comparing the utility of wastewater tracers between temperate and tropical coastal urbanized embayments. Ocean Sciences Meeting 2022, NA, Virtual, February 24 - March 04, 2022.
Impact/Purpose:
The high concentration of people living on or near the coasts results in the discharge of wastewater or other sources of pollution and burdens coastal ecosystems. We used caffeine and sucralose as wastewater tracers to study the distribution of compounds sourced from human waste. By comparing the distribution of these compounds across different estuaries, we seek to learn how different estuaries respond between regions with markedly different climates. These climatic differences are expected to alter the degradation of natural and human derived organic chemicals and therefore result in different exposure outcomes in each location. This study found that although the ratio of these two compounds were similar between estuaries, clear differences existed which pointed to enhanced degradation of organic compounds tropical systems.
Description:
Approximately forty percent of the world’s population lives within 100 km of the coast and, as a result of human activity, nutrients and co-pollutants are discharged to estuarine ecosystems via surface water runoff, groundwater flows as well as direct and indirect wastewater discharges. However, treatment levels of wastewater before discharge to the environment and impacts associated with these effluents often vary widely with geography and socioeconomic development. This study used measurements of known wastewater tracers, caffeine and sucralose, in two coastal embayments (San Juan Bay, PR, and Narragansett Bay, RI) to compare anthropogenic impairment of the estuaries and tracer performance. These locations are both similar in level of urbanization but very different climate and socioeconomic conditions, which may impact tracer performance. By comparing the distribution of these compounds across different estuaries, we seek to learn how different estuaries respond between regions with markedly different climates. These climatic differences are expected to alter the degradation of natural and human derived organic chemicals and therefore result in different exposure outcomes in each location. Ratios of wastewater tracers were similar in both regions, however differences in concentration levels were observed in surface waters and ancillary data suggested surface water hydrology and precipitation as the driver of these differences. Warmer temperatures and more active microbial communities in tropical ecosystems are hypothesized to degrade organic contaminants more quickly, which these data partially support. Despite differences in tracer behavior between estuaries, the discussed results further demonstrate their utility in identifying and tracing wastewater inputs to surface waters.
