In:
Journal of Environmental Quality, Wiley, Vol. 37, No. 6 ( 2008-11), p. 2116-2124
Kurzfassung:
In–situ stabilization using phosphate (P) amendments, such as P‐based fertilizers and rock, are a potentially cost‐effective and minimally disruptive alternative for stabilizing Pb in soils. We examined the effect of time (0–365 d), in vitro extraction pH (1.5 vs. 2.3), and dosage of three P‐based amendments on the bioaccessibility (as a surrogate for oral bioavailability) of Pb in 10 soils from U.S. Department of Defense facilities. Initial untreated soil bioaccessibility consistently exceeded the U.S. Environmental Protection Agency default value of 60% relative bioavailability, with higher bioaccessibility consistently observed at an in vitro extraction pH of 1.5 vs. 2.3. Although P‐based amendments statistically ( P 〈 0.05) reduced bioaccessibility in many instances, with reductions dependent on the amendment and dosage, large amendment dosages (approximately 20–25% by mass to yield 5% P by mass) were required to reduce average bioaccessibility by approximately 25%. For most amendment combinations, reductions continued to occur for periods up to 1 yr, indicating that the observed reductions were not merely experimental artifacts of the in vitro extraction procedure. Although our results indicated that reductions in Pb bioaccessibility with P amendments are technically feasible, relatively large amendment masses were required to achieve relatively modest reductions in bioaccessibility. The cost and potential environmental implications of adding such large amounts of P may limit the practicality of in situ immobilization for some Pb‐contaminated soils, industrial and firing range soils in particular.
Materialart:
Online-Ressource
ISSN:
0047-2425
,
1537-2537
DOI:
10.2134/jeq2007.0426
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2008
ZDB Id:
120525-0
ZDB Id:
2050469-X
