Urban agriculture has gained popularity as an alternate farming system in urban areas, and as means to reclaim vacant unused land, and benefit the local economy. Newark, New Jersey has over 80 urban gardens located in its five wards. Longstanding contamination issues, especially of legacy pollutants, make farming in Newark’s urban soils challenging. Soils from seven community gardens located across four wards of the city were sampled and analyzed for heavy metals. Lead (Pb) was found to be the dominant heavy metal in most soils. A 1M HNO<sub>3</sub> extraction was used to determine total Pb concentrations in soil particle size fractions ranging from &lt;0.125–2 mm. For the 2 mm fraction, a 4-step Tessier sequential extraction was used to determine Pb concentrations in chemical fractions. Most garden soils contained detectable Pb, and three gardens had at least one sample exceeding the EPA Pb limit of 400 ppm. Sequential extraction results indicated that Pb concentrations ranged from 1- 915 ppm in the exchangeable and acid soluble fractions, and from 1-2240 ppm in the non-labile fractions. X-ray absorption fine structure spectroscopy (XAFS) was used to determine the speciation of Pb in sequentially extracted and particle size fractions with Pb &gt; 400 ppm. As finer particle size fractions tended to contain more Pb, human exposure through inhalation and ingestion may be of concern when farming in soils with high Pb concentrations. Results were used to advise garden managers on best practices for farming in metal-contaminated soils, and to engage undergraduate students through research, coursework and field visits.

Study of urban soil lead in community gardens of Newark, New Jersey

2019 Fall National Meeting

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