Professor Dan Brabander Analyzes Lead Levels in City Compost as Urban Gardeners Seek Sources of Low-Lead Compost

Geosciences professor Dan Brabander spoke with National Public Radio’s All Things Considered for a story on the urban gardening crisis in Boston. This past summer the City of Boston announced that the free compost that had been made available to residents and community garden groups was no longer going to be distributed due to rising lead levels.

Since 2003, Brabander and his Wellesley research students have been working with the nonprofit organization The Food Project to monitor lead levels in soil and compost at a Dorchester farm and neighboring residential plots. With more than a thousand analyses, the average lead concentration in garden soils in these neighborhoods was found to exceed the EPA benchmark for lead in soils by a factor of two. Building raised beds filled with city compost then became an important component of developing best practices for safer urban gardening in the context of high lead soils.  

Brabander told WBUR’s Sacha Pfeiffer that lead levels in city compost—used in hundreds of raised bed gardens throughout Roxbury and Dorchester—have doubled since 2009. With the assistance of Wellesley students, Brabander is working to determine where that lead is coming from. Modeling efforts to date can now determine the relative abundances of feedstocks used in compost facilities. The goal is to identify the high-lead waste streams and to modify collection and handling processes so that average lead concentrations in municipal compost falls back to the 150 parts per million range.

Nutrient-rich compost, known by many gardeners as “black gold,” is a precious tool in growing healthy edible urban gardens, which in turn is key to the reduction of food deserts in urban areas and provides produce that is part of the lead-safe diet guidelines. Maia Fitzstevens ‘13, a student in Brabander’s lab, calculated the approximate costs of replacing city compost with alternate products. “Each raised bed garden’s compost requires $61 in start-up costs and $12 in yearly addition of compost," she said. “As there are nearly 700 raised beds in the Food Project neighborhood, the cost has become a challenge for many gardeners who once benefited from free compost.”
 
Brabander and his current group of research students including Sarah George '14, Maia Fitzstevens '13, and Marjorie Cantine '13 will present at the Geological Society of America Annual meeting in Charlotte, N.C., November 4-7, 2012, on the next steps in compost research including geochemical fingerprinting lead sources and designing techniques to immobilize the lead present in compost.

Listen to the story in its entirety on WBUR's website.