On Thursday, Sept. 15, the Macalester community gathered to listen to a combined panel of professors and students present on environmental issues that have stemmed from redlining in the Twin Cities metropolitan area.

After a brief introduction from environmental studies (ES) professor Anika Bratt, ES guest professor Hannah Ramer began the presentation by talking about the history of racial covenants. Racial covenants were a system where plots or areas of land could only be bought by people of a certain race, and they almost exclusively benefited white people.

“[Racial covenants] were a way to exclude certain racial groups from the benefits of property ownership,” Ramer said.

She went on to talk about how racial covenants usually “ran with the land” to permanently exclude certain racial groups from ever owning that land. These covenants were sometimes applied to individual parcels of land, but more often they applied to whole neighborhoods. The covenants weren’t outlawed until the Fair Housing Act of 1968.

There are numerous examples of racial covenants in the Twin Cities, but Ramer focused on one near Como Park where a residential developer, Thomas Frankson, used Como Park and the exclusion of people of color to advertise his development in the surrounding area.

“[Frankson was] bundling urban greenspace and whiteness to create value in the real estate market,” Ramer said.

Ramer discussed how the definition of “whiteness” has changed throughout history. People’s immigration status and spoken language were often factors when determining if they got access to the benefits of “whiteness.” She emphasized that for Frankson, race was more important than any other factor.

“The racial hierarchy at the time took priority over citizenship, over primary language, over birthplace, as Swedish immigrants were incorporated into the category of white,” Ramer said.

Ramer then introduced the topic of redlining, a system of ranking land on a scale from “desirable” to “hazardous,” and how racial covenants often were a major factor in these rankings.

“Areas that had access to greenspace and parks that had racial covenants on them tended to be categorized as most desirable,” Ramer said.

The presentation then shifted to focus on biology professor Mary Heskel’s research where she used leaf radiocarbon isotope ratios and satellite remote sensing to examine the environmental legacies of redlining.

First, she talked about what radiocarbon isotope ratios are and how they can be used to track pollution.

By collecting leaves, she was able to see if there was higher or lower fossil fuel air pollution in an area based on how much carbon-14 was in those leaves, with lower amounts of carbon-14 indicating higher fossil fuel air pollution rates.

Despite only being able to use six leaves due to high costs, areas deemed “desirable” by redlining had less carbon dioxide in the air according to radio carbons than areas deemed “hazardous.” She hopes that this will be a pilot study for this kind of pollution detection and that in the future sample sizes can be larger.

However, radiocarbon ratios were not the only method she used to track pollution. She also used a much larger scale method called satellite remote sensing.

Satellite remote sensing is a form of data where satellites detect the amount of a certain material, often a pollutive, in the troposphere.

“I think satellite remote sensing is a fantastic tool when on-the-ground measurements are not available, and they’re not in many places,” Heskel said.

By looking at nitrogen dioxide levels in the atmosphere above Midwestern cities, Heskel found that some cities had statistically significant differences between “desirable” and “hazardous” zones, and some did not. However, she did point out some limitations of this kind of data collection and hoped that her study will be a catalyst for expanding data collection systems that are more relevant to people on the ground.

“This is tropospheric data, not the lived experiences of people walking around, that has huge public health implications,” Heskel said. “I think it could be a first pass where you could set up ground-based sensors where people actually live, not the airport.”  

The presentation then transitioned to a focus on water quality, starting with Ahmed Abdalla Ahmed ’23 who talked about his research using existing water quality detection systems set up by the local government.

These detection systems involve sensors that publicly collect data on the amount of pollutants in the water. Abdalla Ahmed analyzed the data to look at differences between redlined areas.

“In [hazardous] areas, total nitrogen content and phosphorus content is higher than in [desirable] areas,” Abdalla Ahmed said.

Since this data has been collected by the government, it has been accumulating for decades in many different areas, meaning the data set is expansive.

“We were quite surprised that it can be this pronounced, especially given that it was such a huge data set,” Abdalla Ahmed said. “These are thousands of points that, for some lakes, they started collecting data in the 70s up until 2021. [For] some other lakes, they started collecting in the early 2000s and then stopped in the 2010s.”

This data is especially concerning considering that it’s focused on total nitrogen content and phosphorus, which can both indicate algae growth. Alexandra Jabbarpour ’23 talked about how excessive algae growth can affect both wildlife and people near these ponds and lakes.

“When there’s more nitrogen and phosphorus that go into the water it can increase algae blooms, and algae blooms can decrease oxygen levels in the water which can cause fish to die, but we were especially interested in harmful algae blooms,” Jabbarpour said.

Jabbarpour discussed her own research in coordination with Abdalla Ahmed where she focused on ponds and lakes that were smaller and lacked government water quality detectors. She was concerned about how these smaller ponds and lakes are often in residential communities.

Since there aren’t any established water quality detectors in these ponds and lakes, she had to collect and analyze these samples herself along with one of her colleagues to see if there were harmful algae blooms present in the water.

“Harmful algae is algae which can potentially produce toxins,” Jabbarpour said. “So the book is showing microcystis which produces the toxin microcystin which harms fish and wildlife, but could also harm people and has been known to have killed dogs as well as babies.” 

She found that these smaller lakes and ponds often contain harmful algae and that communities deemed “hazardous” by redlining often have more water pollution causing these algae blooms.

“We think since [in hazardous areas] there’s more air pollution and then less greenspace, so less trees and vegetation to pick that up, where’s it gonna go?Because when it rains it’s either picked up by the vegetation or it goes into the lakes and ponds,” Jabbarpour said. 

Jabbarpour concluded the presentation by emphasizing the importance of this type of informative research.

“The goal is to let people know and also to hopefully have policies that can fight against this because these are health concerns,” Jabbarpour said.

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