Page 202 - Plant-Based Remediation Processes

194 A. Branzini and M.S. Zubillaga

Consequently, in order to reduce significantly the loss of heavy metal to the environ-
ment by human activities, recycling is an interesting part solution. In addition, this
action could avoid the new metal entering into circulation. As a result, a metal-
containing waste could be converted to product. However, reality is that significant
quantities of heavy metals will never be collected for recycling by the present waste
management systems. Thus recycling will not prevent a continued release to the
environment of heavy metals in circulation in the technosphere.

10.5 Conclusions

The effects of mixtures of heavy metals’ incorporation into soil and their toxic
properties are important challenges that we have to outface. In addition, the
utilization of in situ technologies to remediate the effects has to be carefully
selected due to the objective of remediation. Amendments and phytostabilization
could adsorb, bind, or co-precipitate the contaminating metals and/or can use plants
for immobilization of toxic metals. Consequently, stabilization of heavy metals in
soil appears as a low-cost alternative and supposes an attractive and emerging
technology for site restoration. However, it has to be clear that these strategies
require monitoring process. The use of plants in combination with chemical
amendments in designing low-cost treatment system is still a challenge in environ-
mental managements. In fact, in Argentina, there are some species like Sesbania
virgata, which have high capacity to tolerate and accumulate heavy metals in their
tissues, being useful for phytostabilization of contaminated soils with mixtures of
heavy metals.

References

Adriano DC (2001) Trace elements in terrestrial environments. Biogeochemistry, bioavailability
and risks of metals, 2nd edn. Springer, New York
Adriano DC, Wenzel WW, Vangronsveld J, Bolan NS (2004) Role of assisted natural remediation
in environmental cleanup. Geoderma 122:121–142
Alloway BJ (1995) The origins of heavy metals in soils. In: Alloway BJ (ed) Heavy metals in soils,
2nd edn. Blackie Academic and Professional, London
Alvarez JM, Almendros P, Gonzalez D (2008) Residual effects of natural Zn chelates on navy bean
response, Zn leaching and soil Zn status. Plant Soil 317:277–291
Basta NT, McGowen SL (2004) Evaluation of chemical immobilization treatments for reducing
heavy metal transport in a smelter-contaminated soil. Environ Pollut 127:73–82
Basta NT, Gradwohl R, Snethen KL, Schroder JL (2001) Chemical immobilization of lead, zinc
and cadmium in smelter-contaminated soils using bio solids and rock phosphate. J Environ
Qual 30:1222–1230
Basta NT, Ryan JA, Chaney RL (2005) Trace elements chemistry in residual-treated soil: key
concepts and metal bioavailability. J Environ Qual 34:49–63