Coastal Management

Caffeinated Seas: Unique Tracers for Wastewater-borne Contaminants

Cantwell, M.G., Katz, D.R., Sullivan, J.C., Lyman, M. (2019) Evaluation of wastewater tracers to predict pharmaceutical distributions and behavior in the Long Island Sound estuary. Chemosphere 220: 629-636.

Did you ever think your coffee addiction could help solve marine pollution? It turns out all that caffeine and artificial sweetener does more than just give you that afternoon energy boost. Outside of New York City in the Long Island Sound, scientists are evaluating the use of your coffee byproducts as tracers for wastewater contamination.

Newton Wastewater Treatment Plant. Source: Wikimedia Commons

Drugs in our Oceans

When it comes to marine pollution, many news sources highlight stories of megafauna entangled in plastic waste, but just out of sight is an equally dangerous pollutant: pharmaceutical residue. Basically, medicinal drugs end up suspended in our waterways after improper disposal and marine organisms may be negatively impacted. One impact of pharmaceuticals in the ocean is the feminization of fish from birth control pills, but broader impacts like biomagnification have yet to be thoroughly quantified.

Leave no Trace?

Estuaries often bridge the gap between urban hubs and marine ecosystems, and are therefore riddled with wastewater contaminants. This is especially true when they are located outside of one of the United States’ largest cities. In the Long Island Sound estuary, Cantwell et al. (2019) examined the sources and distribution of trace pharmaceuticals from wastewater treatment facilities. In 17 water samples from both the Sound and connecting rivers, the scientists measured concentrations of 16 highly prescribed pharmaceuticals (Figure 2).

Figure 2. Study Area (Long Island Sound). Source: Google Maps

Go with the Flow

The estuarine morphology and its physical processes provide insight into the distribution of pharmaceuticals. Cantwell et al. (2019) found highest concentrations of many of the pharmaceuticals where the large East River, home of many wastewater treatment facilities, meets the Long Island Sound estuary. Following the river eastward toward the Atlantic Ocean, levels of pharmaceuticals decreased. This decrease in pharmaceutical concentration also follows an increase in salinity as the water flows out towards the sea. Finally, of all 16 tested pharmaceuticals, only about half of them were found at every site.

Not Your Average Cup of Joe

So how does your cup of joe affect pharmaceutical contamination? The human body does not completely metabolize caffeine and artificial sweeteners (sucralose), and on top of that, wastewater treatment plants do not effectively remove these byproducts. As a result, both caffeine and sucralose end up in the Long Island Sound estuary and many other coastal bodies of water. So, what do these coffee ingredients and toxic pharmaceuticals have in common? They all most likely came from wastewater treatment plants.

Cantwell et al. (2019) showed that in the estuary, sucralose and caffeine levels corresponded to pharmaceutical concentrations. This makes these byproducts strong candidates for becoming wastewater tracers, or indicators of sites with other wastewater contaminants. Of the two tracers, however, sucralose proved to be a stronger indicator as it did not degrade as rapidly as caffeine.

With the help of tracers like sucralose that are ubiquitous in the marine environment, we can help pinpoint the location of high amounts of harmful pharmaceuticals. So, keep sipping that frappe and help scientists track dangerous wastewater contaminants!

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