Lead Laden Soil
an easier way to test
By Alyse Horn
“People are worried about water, and they should be, but water is not the main driver of lead poisoning among children.”
Jonathan Burgess [pictured above], senior agriculture conservationist at Allegheny County Conservation District, said studies show the majority of lead poisoning comes from dust and paint.
“Not water.”
Burgess said the sources of lead contaminants, such as lead smelters, gasoline, and lead paint, end up in soil. Lead contaminated soil can be found in playgrounds, gardens, and vacant lots. Around the country there is a lot of interest in soil lead levels, particularly in old industrialized cities, like Detroit and Pittsburgh.
An easier way to test
In the Steel City, groups like ACCD, DECO Resources, and Grow Pittsburgh have been able to conduct studies on soil lead levels in neighborhood vacant lots using an X-ray Florescent Spectrometer, also known as the XRF. This handheld machine can test soil for lead and receive results in about 60 seconds.
“We affectionately call it the soil ray gun,” said Anthony Stewart, president and environmental director of DECO Resources.
At the end of 2015, Burgess said ACCD started looking for ways to make it easier for organizations to test soil lead levels. Before getting the XRF, soil samples had to be sent to labs at Penn State University or the University of Massachusetts, costing money and time. Tests cost $15 to $66 and take up to two weeks for results.
“You can get a grant to pay for soil tests, but how quickly does that run out? So we started looking into purchasing equipment to do that in house,” Burgess said. “That led us to XRF technology.”
The ACCD reached out to the Environmental Protection Agency and other organizations for advice on using the equipment in field exploration. Burgess said not many people are using XRF to test soil levels, and it is mainly for testing the metal makeup of rocks or determining if there are metals in soil or paint. But, it can be used to test lead levels in soil if the soil is processed properly. With a grant from the Hillman Family Foundation, the ACCD purchased an XRF.
To properly test the soil in a vacant lot for lead, Stewart said the lot is first broken up into areas that are usually 10 square feet and five samples are taken from each section. The soil must then be dried and processed into fine granules before being tested by the XRF. With this level of analysis, Stewart said they have been getting “laboratory grade results.”
“We do send out 10 to 15 percent of our samples off to a lab for confirmation, and we are finding that we are spot on,” Stewart said.
Countywide soil lead screenings
Since obtaining the XRF, the ACCD has been holding free soil screenings for neighborhoods around Pittsburgh and the county. By asking the participants nearest intersections, Burgess said they are able to start compiling data of lead levels around the area with the goal of sharing those larger findings publically.
“[We want] to engage people and give them information on how to deal with and mitigate the problem,” Burgess said.
They also conducted a large-scale pilot test in Larimer with evolveEA and took over 400 soil samples from the area. Stewart said they ended up finding a lot of variability, with high levels of lead next to low levels of lead.
Rachel Bukowitz, a soil science fellow with ACCD and recent University of Pittsburgh graduate, said there were two 10 square foot areas within the Larimer lots that had particularly high lead levels. Working out of Dr. Daniel Bain’s lab at the University of Pittsburgh, she began testing different soil amendments and how each affected the lead levels in soil with the goal of remediating it.
“Specifically I was looking at bioavailability,” Bukowitz said.
By adding different soil amendments, Bukowitz said she was changing the pH balance of the organic matter and changing “how much of that lead is actually a potential threat to become bioavailable and become a harm for anyone in those lots.”
Bukowitz said she chose compost, woodchips, and lime for her soil amendments. Compost and woodchips are organic matter, which lead in soil will bind to, making the lead less bioavailable. Lime, Bukowitz said, raises the pH in soil making it more alkaline, which would also result in decreasing the bioavailability of lead.
Shelly Danko+Day, the open space specialist for the City, said she became aware of soil lead levels in the area in 2006 when she was working for Grow Pittsburgh. Danko+Day said once they started testing the soil, they were finding levels of lead that were dangerous for children and others to be working in.
In 2014 when Danko+Day started working for the City, she said the first thing she did was create a soil policy and standards for the Adopt-A-Lot program that made lead testing mandatory. Stewart said the City only requires one test from each vacant lot, which he believes is inadequate because of lead variability, but Danko+Day said each test has a composite of eight to ten samples from a lot.
“While it’s true we only require one soil test per project, primarily to keep the costs low for the applicants, they are free to take more if they would like,” Danko+Day said.
“While it’s true we only require one soil test per project, primarily to keep the costs low for the applicants, they are free to take more if they would like,” Danko+Day said.
Burgess said this has been the standard for lead testing in many different cities, but “because of how quickly land use and prior land use changes every couple of feet,” there is a lot of variation within 5 to 10 feet. Burgess understands the City doesn’t want to make vacant lot rehabilitation cost prohibitive to well-meaning people, which is why the ACCD offers free soil screenings with the XRF.
Getting the community involved
Danko+Day has been working with Stewart and Jmar Bey, president of South Hilltop Men’s Group, to help them gain permission to experiment with soil remediation techniques in four lots on Beltzhoover Avenue. The lots, Stewart said, have lead levels between 400-1,000 parts per million, meaning technically they are not allowed to dig into the soil and must use raised beds per City guidelines.
Stewart said he and Bey were able to work out an Adopt-A-Lot agreement with Danko+Day and they will use raised beds, “but the idea is that even though we aren’t going to be digging into the soil, the plants will still root.”
“We are using a completely natural process to begin mixing that soil, so when we go and test again we hope that those levels of lead are lower,” Stewart said. “Then we will be able to till that soil and really reduce those levels of lead completely within the code of the City.”
Stewart and Bey will start with sunflowers, hops and mustard greens in several soil blends that include two different amendments: woodchips and compost. All three plants are effective at removing lead from soil, and this study will determine what plants and amendments work best at making the soil less harmful for humans. Eventually oyster mushrooms will also be added, which Stewart said through a process called chelation will pull the lead out of the soil and into the mushrooms roots.
The SHMG recently received a grant from the Conservation Leadership and Innovation Program through the ACCD, which allows the project to move forward with DECO as the consultant. Stewart said the goal is to have members of the community become certified in maintaining the lots so “they won’t need companies like us.”
“We are trying to empower the community to be able to take ownership of these sites that may have elevated levels of lead,” Stewart said.
Within Pittsburgh’s scientific community, a collection of individuals from various organizations have formed the Urban Soil Working Group with the intentions of educating the public on how to deal with lead in soil and creating guidelines.
Stewart, who is part of the group, said he would like to see collaboration between the organization and the City so “vetted scientists” would be allowed to access the City’s soil data that is currently internal and private.
“It would be incredibly helpful… to use that data to drive policy and decision making,” Stewart said. “That’s kind of where I see the shortcoming right now.”
Writer: Alyse Horn
Photographer & Web Producer: Will Halim
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[…] lots each contain soil lead levels between 400 – 1,000 parts per million, which designates their use as limited under City code. A series of 24 raised beds are to be constructed on this land, each of which will contain a […]