Evaluation of the effectiveness of <i>in situ</i> stabilization in the field aged arsenic-contaminated soil: Chemical extractability and biological response

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The effectiveness of <I>in situ</I> stabilization in the long-term As-contaminated soil was assessed. <I>In situ</I> stabilization of As was conducted through a Fe-based sorbent amendment. Chemical extractability of As was first determined by solubility/bioavailability research consortium extraction method and any change in human health risk through oral ingestion was characterized. Also, nonspecifically bound As in soil was determined by five-step sequential extraction. The results indicate that such extractable fractions of As decreased, and consequently risk through oral ingestion decreased probably due to hematite transformed from both the goethite in the original soil and the Fe-based sorbent, which was identified through the X-ray absorption spectroscopy. In ecotoxicity test with <I>Hordeum vulgare</I>, root and shoot elongation and germination rate decreased which was contrary to the chemical extraction data. Such increase in As toxicity is because of increased exchangeable Ca<SUP>2+</SUP> concentration causing As accumulation in the membrane surface of <I>H. vulgare</I>. Also, adsorption of phosphorus onto the Fe-based sorbent decreased available phosphorus concentration causing phosphorus deficiency for growth. Our results demonstrate that the effectiveness of <I>in situ</I> stabilization should be evaluated by means of both chemical extractability and biological response, as chemical analysis alone may not be sufficient to assess the ecotoxicity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>In situ</I> stabilization with Fe-based sorbent in As-contaminated soil was conducted. </LI> <LI> The effectiveness of <I>in situ</I> stabilization was evaluated chemically and biologically. </LI> <LI> Chemical extractability of As decreased, probably due to formation of hematite. </LI> <LI> Ecotoxicity to <I>H. vulgare</I> increased, owing to changes in soil properties. </LI> <LI> Chemical extractability and biological responses must be monitored concurrently. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>