A simple kit to detect extractable lead concentrations in soil
Year: 2025
Type: article
Abstract: Lead (Pb) contamination of soil is often spatially very heterogeneous and therefore difficult to map and remediate. To address the issue, we simplified a previously developed screening method that relies on an acidic glycine solution to extract Pb from soil and the precipitation of purple Pb rhodizonate as a visual indicator to avoid filtration of the extract. The simplified kit is limited to a plastic test tube, a soluble capsule of glycine hydrochloride crystals, a strip of pH paper, and a commercial cotton swab impregnated with sodium rhodizonate designed for testing Pb-based paint. The swab turns purple at a concentration in the extract equivalent to a concentration of ~200 mg/kg Pb in soil. The swab method was evaluated using 201 dried and sieved soil samples from the US and Peru spanning the 100-10,000 mg/kg range in total Pb concentrations. Excluding 14 samples from Peru with an extract pH>3, the results show a sensitivity and a selectivity of 85% relative to an extractable Pb concentration of 200 mg/kg in the extract measured by X-ray fluorescence. The US Environmental Protection Agency’s screening level for bare residential soil in areas where children play was recently lowered to 200 mg/kg total Pb. Depending on the proportion extractable Pb, this simple kit could help households and communities map soil contamination with Pb from mining, smelting, battery recycling, and flaking paint at or near the new screening level.
Source: Geoderma
Institution: Columbia University
Language: English
Topic: Heavy metals in environment
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,320
OpenAlex ID: W4414112054