UMD Researcher is Using Soil Chemistry to Help Bridge the Gaps in African American History through Collaboration with Howard University’s New York African Burial Ground Project

New publication in Nature Scientific Reports combines anthropology and soil chemistry to give a more complete picture of how freed and enslaved Africans lived

African Burial Ground in Manhattan

Image Credit: Preserve America

February 17, 2020 Samantha Watters

What can soil tell us about African American history? In a new paper published in Nature Scientific Reports, Howard University teamed up with UMD lecturer Candice Duncan, Department of Environmental Science & Technology, to tackle that question. As a soil chemist, Duncan’s input is helping to unlock the secrets held in grave soil samples from the New York African Burial Ground (the largest African burial ground in the country) using hard soil chemistry, a discipline that is not commonly combined with anthropology. In this preliminary pioneering work, Duncan and the team at Howard - home to the entire collection of soils, remains, and artifacts uncovered by the African Burial Ground Project in New York - have proven the effectiveness of nondestructive methods of soil chemistry to identify trace metals in the soil and make anthropological inferences about the way its inhabitants lived.

“We know a lot of the history of how Africans came here to the US and the injustices in that process, but when they got here and after they were freed, it’s nice to know how they survived,” says Duncan. “What did they eat? How did they live? What trades were they doing? The collection at Howard could give us pieces to that puzzle, and maybe one day we will get a complete picture, which is currently a gap in African American heritage. I wanted to know, ‘What could I learn from this that I couldn’t read about?’”

The research on these grave soil samples is currently being led at Howard University by Carter Clinton, doctoral candidate in biological anthropology and assistant curator at the W. Montague Cobb Research Laboratory. Duncan is a member of his dissertation committee, “Bacterial, elemental, and geospatial analysis of 17th and 18th Century New York African Burial Ground grave soil samples,” and all soil chemical analyses were conducted on site at UMD by Clinton and Duncan in Ray Weil’s lab, professor and renowned soil scientist.

With this new work incorporating soil chemistry, preliminary findings show high levels of arsenic, copper, and zinc in the soil that suggest the site was being used as a dumping ground by local kilns and pottery factories, but the presence of artifacts could also suggest this as a potential trade for freed African slaves. Additionally, high levels of strontium were found.

“The interesting thing is when you see these elevated levels of strontium in human remains, it’s an indicator of a vegetative diet,” says Clinton. Soil chemistry is the first component of his work, but Clinton is also looking at bacterial DNA and microbial compounds in the soil, the geospatial mapping of the soil, and bioethical components of how all of these data come together to tell a complete story.

African Burial Ground National Monument, New York
African Burial Ground National Monument, New York, by Carol M. Highsmith, Library of Congress

“Reconstructing these data gives us real insight into what life was like back then,” says Fatimah Jackson, professor emerita at UMD and now the director of the W. Montague Cobb Research Laboratory at Howard University leading this project and Clinton’s doctoral committee. Using biological and dental analysis, researchers at Howard have already gone a long way in filling in the gaps in the biological history of African Americans, uncovering the age of remains, life expectancy, and making inferences about where these inhabitants came from.

Duncan is thrilled to be a part of this work as a way for African American researchers to own their history, a key reason why the samples were entrusted to Howard University and Jackson’s lab. As a soil chemist, Duncan is also particularly excited to bring together the fields of soil chemistry and anthropology to show the benefits of a historical perspective in science, and a scientific perspective in history. 

“What really sparked my interest was the history behind it all. We don’t always connect the historical and anthropological background to some of the hard sciences, even though those hard sciences like biology and chemistry can help tell the story of what happened from a historical perspective,” says Duncan. “Here, we are trying to put a timeline together based on what layers were being added to the soil over what periods of time. It’s still soil chemistry, but now we have a better story to tell. We have much more to say because it has a history and means something personal to a lot of people, including the researchers in this project. I find that very fascinating, and would hope others have that same fascination.”

The team hopes to continue work on these samples and do more in depth chemical analysis in the future to learn more about the people who were buried at this site, confirm preliminary findings, and connect this with chemical analysis of bone and artifact samples. “This work has the potential to make a significant impact as we obtain more and more chemical information using the samples,” says Duncan. “I look at the whole collection of samples as an information chip in time, and we are decoding to get a story from it. Long term, I see it giving us a lot of information about enslaved, now free, Africans being able to have a say in their true lineage.”

The paper, entitled “Identification of trace metals and potential anthropogenic influences on the historic New York African Burial Ground population: A pXRF technology approach,” is published in Nature Scientific Reports.