Soil Contaminant Concentrations at Urban Agricultural Sites in New Orleans, Louisiana: A Comparison of Two Analytical Methods

Bridget Simon-Friedt,Jeffery Wickliffe,Mark Wilson,Kyle Moller,James Hartwell

doi:10.5304/jafscd.2018.082.010

Abstract

Along with the many benefits of urban agriculture comes the possible exposure to contaminants not typically seen in rural soils. Through the use of standard laboratory analyses (ICP-AES and CVAAS) and a field-portable X-ray fluorescence spectrometer (XRF) calibrated for soil analysis, this study quantified contamination levels at urban agricultural sites throughout New Orleans, Louisiana. The results of the standard laboratory analyses were compared to the results from the XRF. We collected soil samples at 27 urban and suburban farm and garden sites from the Greater New Orleans area. We analyzed the soil samples for arsenic, cadmium, chromium, cobalt, copper, mercury, lead, nickel, and zinc using the XRF and standard methods. Most sites had median concentrations significantly below Louisiana’s soil standards. Paired soil samples showed XRF results were significantly higher than laboratory results for all metals but copper. Only lead (ρ=0.82, p<0.0001) and zinc (ρ=0.78, p=0.0001) were highly correlated. Poor correlation of results between XRF and standard methods make the standard methods preferred. See the press release for this article.

Highlights

This study examines soil contamination of urban agriculture in New Orleans, Louisiana
This study examines arsenic, cadmium, chromium, cobalt, copper, lead, mercury, nickel, and zinc; These substances are all soil contaminants of concern to human health (Bruker, n.d.)
The X-ray fluorescence spectrometer (XRF) consistently showed higher results compared to the laboratory analyses

Summary

Introduction

Introduction and Literature ReviewUrban agriculture can provide numerous benefits to people and communities by improving food security and local food economies, reducing transportation costs, and revitalizing blighted neighborhoods (Brown & Jameton, 2000; Cohen, 2011; Hagey, Rice, & Flournoy, 2012; Kim, Poulsen, Margulies, Dix, Palmer, & Nachman, 2014; Mougeot, 2000; Patel, 1991; Rose, Bodor, Swalm, Rice, Farley, & Hutchinson, 2009; Smit & Nasr, 1992; Sommers & Smit, 1994). This study examines soil contamination of urban agriculture in New Orleans, Louisiana Cities such as New Orleans with historic and current industrial activity, high-traffic, and leadpainted houses often have higher levels of soil contamination (Brown & Jameton, 2000; Finster, Gray, & Binns, 2004; Grubinger & Ross, 2011; Laidlaw & Filippelli, 2008; Meuser, 2010; Mielke, Wang, Gonzales, Le, Quach, & Mielke, 2001; Mielke & Reagan, 1998; Wu, Edwards, He, Liu, & Kleinman, 2010). Studies examining New Orleans have shown high levels of soil contamination from metals (Mielke et al, 2001; Mielke, Wang, Gonzales, Powell, Le, & Quach, 2004; Mielke, Gonzales, Smith, & Mielke, 2000). Past lead levels in New Orleans have been found to range from non-detectable levels to 190,980 parts per million (ppm), with a median of 120.4 ppm (Mielke, Gonzales, Smith, & Mielke, 2000)

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