Tobacco Product Chemicals Harm Natural Environments: A Case Study in Mission Bay Park, San Diego

Sixteen acres of salt marsh are nestled in the northern end of Mission Bay Park in San Diego. This area, the Kendall-Frost Mission Bay Marsh Reserve, is supposed to be untouched by people, providing a safe habitat for the light-footed clapper rail and the Belding’s savannah sparrow, two endangered birds calling Mission Bay their home. In addition, all of Mission Bay Park is smokefree to protect people and the environment from tobacco smoke and product waste. Even with these protections, a recent study detected nicotine and cotinine, two toxic tobacco chemicals, in the reserve.

a painting of a tan light footed clapper rail bird walks by the water next to a cigarette butt

How did the chemicals get there? Was it simply people breaking the smokefree rule, or is there something bigger happening? What can we do to avoid tobacco pollution in the reserve and throughout Mission Bay in the future?

Read on to learn more about this study and explore the data to see what lead researcher Dr. Srimanti Duttagupta, an environmental scientist at San Diego State University, found through her research at the Kendall-Frost Mission Bay Marsh Reserve.

map of mission bay

For her study, Duttagupta took samples from two sites in the Kendall-Frost Mission Bay Marsh Reserve (blue dots). The first one, the Noyes St. site, does not connect to any bodies of water. The second, the Olney St. site, is connected to Mission Bay.

Duttagupta measured nicotine and cotinine levels in the water at each site 26 times between November 2019 and February 2022. She found the most nicotine in the water at Noyes St. in February 2021. She found the most cotinine at Noyes St. in July 2021. Hover over the data points on the graphs below to see the other measurements.

Duttagupta also measured nicotine and cotinine levels in the sediment at each site. She found the most nicotine in the sediment at Noyes St. in November 2020. She found the most cotinine at Noyes St. in August 2020. Hover over the data points on the graphs to see the other measurements.

Noyes St. likely had higher nicotine and cotinine levels because this drainage site has stagnant water. All of the water at this site came from runoff from the street, which carried cigarette butts and other litter into the site. This trash polluted the water with tobacco chemicals. There was no additional water to dilute it. In comparison, the Olney St. site connects to Mission Bay, which helped dilute the runoff water at this site.

Precipitation impacted the nicotine and cotinine levels as well. A little less than two-thirds of the sampling events took place during a wet season. Overall, the samplings during wet seasons had higher nicotine levels. This was especially noticeable at the Noyes St. site, which only contains runoff water. More rain means more runoff, which means more polluted water at the site. Hover over the data points to compare nicotine levels and precipitation.

Duttagupta’s study highlights the impact that upstream tobacco product waste plays in polluting Mission Bay. The water draining into Mission Bay comes from the upstream neighborhoods above Mission Bay. As residents and visitors in these neighborhoods use tobacco, the discarded cigarette butts collect on sidewalks and parking lots where they begin to break apart into microplastics. When it rains, they are swept into the stormwater drains and end up in Mission Bay.

The findings demonstrate the importance of tackling tobacco product waste created in neighborhoods upstream to keep ecosystems and waterways clean. While smoking bans in parks and beach cleanups help keep the environment clean, solutions that deal with the pollution before waste gets in the environment are longer-term and more effective. One of these solutions is educating the public that cigarette filters are single-use plastic that does not biodegrade and pollutes the environment with toxic leachates and microplastics. Other solutions include limiting where tobacco products can be bought, banning all tobacco use in public spaces, prohibiting the sale of filter cigarettes, and proper disposal of all tobacco product waste.

Bringing awareness to the toxic legacy of commercial tobacco products can pave the way to adopting policies to create a tobacco-free world for today’s and future generations of human and animal residents of San Diego County. 

Click here to read the research study.

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