TY - JOUR

T1 - Chemical measures of bioavailability/bioaccessibility of PAHs in soil

T2 - fundamentals to application

AU - Riding, Matthew J.

AU - Doick, Kieron J.

AU - Martin, Francis L.

AU - Jones, Kevin C.

AU - Semple, Kirk T.

PY - 2013/10/15

Y1 - 2013/10/15

N2 - Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.

AB - Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.

KW - Bioavailability

KW - Remediation

KW - Organic contaminants

KW - Chemical extraction

KW - Risk assessment

U2 - 10.1016/j.jhazmat.2013.03.033

DO - 10.1016/j.jhazmat.2013.03.033

M3 - Journal article

C2 - 23583092

VL - 261

SP - 687

EP - 700

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

ER -