Philadelphia’s has been chock full of Industrial fumes, old paint and now-banned gasoline additives putting toxic metals like lead in soil for generations. Is this a serious problem though? Lead is a basic element, so it’s normal to find small amounts in soil. According to the United States Geological Survey, lead in the soil naturally occurs at a level of 33 parts per million in the Philadelphia region. The national average is 19 ppm, and industrial East Coast cities pull that number up with higher concentrations due to longer industrial use.
NBC reports though that a Temple University master’s student Stephen Peterson found lead in higher than expected concentrations throughout the park system.
Sampling twenty-four sites in parks across the city, Peterson was still surprised by how much lead he found and where.
“It turns out only one percent of my samples were at or below that geologic background level,” said Peterson. “Sixteen percent of the soil samples were above the EPA soil saturation limit for residential use, which is 400 ppm.” In a few sites, he found extremely high levels of lead – with one in North Philadelphia clocking in at 10,000 ppm, roughly one percent of the entire soil makeup. “I took that sample next to an old building, so the lead probably came from layers and layers of paint scraping off over the years,” said Peterson.
Peterson also found elevated lead levels in remote parts of the Wissahickon, and other areas with no history of industrial or even residential use.
Another concern for Peterson was Philadelphia’s community gardens so testing for lead in these areas became a focal point of Peterson’s research. “Everywhere that I saw an urban garden, I made sure I tested,” said Peterson. In all of those soil samples, “the level was super low or not even detectable.” Peterson says urban gardeners who use raised beds, bringing in clean soil, are taking the right steps.
Peterson’s research led him to work closely with the Philadelphia Department of Parks and Recreation, which oversees the entire Fairmount Park system. Parks and Recreation already makes recommendations for gardeners and people with yards to test their soil and to plant in raised beds.