Bioavailability-Based In Situ Remediation To Meet Future Lead (Pb) Standards in Urban Soils and Gardens

Abstract

Recently the Centers for Disease Control and Prevention lowered the blood Pb reference value to 5 μg/dL. The lower reference value combined with increased repurposing of postindustrial lands are heightening concerns and driving interest in reducing soil Pb exposures. As a result, regulatory decision makers may lower residential soil screening levels (SSLs), used in setting Pb cleanup levels, to levels that may be difficult to achieve, especially in urban areas. This paper discusses challenges in remediation and bioavailability assessments of Pb in urban soils in the context of lower SSLs and identifies research needs to better address those challenges. Although in situ remediation with phosphate amendments is a viable option, the scope of the problem and conditions in urban settings may necessitate that SSLs be based on bioavailable rather than total Pb concentrations. However, variability in soil composition can influence bioavailability testing and soil amendment effectiveness. More data are urgently needed to better understand this variability and increase confidence in using these approaches in risk-based decision making, particularly in urban areas.

Subcellular Compartmentalization and Chemical Forms of Lead Participate in Lead Tolerance of Robinia pseudoacacia L. with Funneliformis mosseae

“…Pb pollution has also been a serious threat to human health and food safety (Cuypers et al, 2016), especially harmful to young children (Datko-Williams et al, 2014). Over the last decade, evidence has been shown that Pb exposure-related health injury occur already at lower blood Pb levels than previously documented (Henry et al, 2015). Recently, the Centers for Disease Control and Prevention has lowered the reference value of blood Pb level to 5 μg dL -1 (Burns and Gerstenberger, 2014).…”

Using Phosphorus and Zeolite to Immobilize Lead in Two Contrasting Contaminated Urban Soils

“…Even though the effectiveness of Pb immobilization has been reported depending on the phosphate amendment, no significant differences were observed among H 3 PO 4 and/or Ca(H 2 PO 4 ) 2 amendments in the current study. The efficiency of the phosphorus amendment in Pb-contaminated soil has also been reported related to the type of soil and the nature and extent of the contamination [9].…”

“…Henry et al [9] demonstrated that the in situ remediation with phosphate amendments based on bioaccessibility assessments is the best approach. Phosphate (P) amendments are known to form stable Pb-P minerals (i.e., pyromorphite) [10].…”

“…Therefore, quantifying the Pb speciation -particularly of its bioavailable form -under the applied chemical amendments is of utmost importance in risk assessment and remediation [8] . Research is urgently needed to increase confidence in using these approaches in riskbased decision making in the context of natural urban soils [9]. In this study, we conducted batch incubation experiments with amendments (H 3 PO 4 , Ca(H 2 PO 4 ) 2 , H 3 PO 4 + Ca(H 2 PO 4 ) 2 , and zeolite) in two contrasting contaminated urban soils.…”

Incorporating ToxCast and Tox21 datasets to rank biological activity of chemicals at Superfund sites in North Carolina

“…In 2006, the EPA celebrated the completion of construction at the one thousandth Superfund site (EPA, 2015a). The cleanup of these hazardous waste sites has had numerous public health and economical benefits on the surrounding communities (Arndt et al, 1999; EPA, 2011; Gamper-rabindran et al, 2011; Henry et al, 2015). However, many Superfund sites remain as hazardous waste sites that pose significant threats to human health through contaminant exposure via soil, surface water, or ground water (Carlin et al, 2015; Jung et al, 2011; Messier et al, 2012; U.S.…”