 |
| Titel |
Efficiency of single extraction schemes in highlighting the impact of changes in land use of contaminated agricultural soils on their trace metal availability |
| VerfasserIn |
Muhammad Iqbal, Isabelle Lamy, Alain Bermond |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086547
|
| Publikation (Nr.) |
 EGU/EGU2014-436.pdf |
|
|
|
|
|
| Zusammenfassung |
| Presently changes in the land use of contaminated and marginal agricultural lands from
conventional annual food crops to perennial non-food bionergy crops are being
encouraged globally. This is being done to avoid food chain contamination with metal and
organic contaminants and to meet world energy needs without disturbing normal
fertile agricultural lands. Changes in land use from the annual cropping systems to
the perennial cropping systems are known to modify organic matter quality and
quantity in case of non contaminated soils. In the case of contaminated soils such
changes are susceptible to alter trace metal availabilities but studies reporting such
changes are scarce. Different single extraction protocols are used to assess the trace
element availability in soils. The efficiency of these extractants depends upon soil
conditions and may vary case to case. The objective of the present work was to assess
the changes in trace metal availability of contaminated soils when annual crops
system is replaced by a perennial crop system using different single extraction
protocols.
A strategy of studying Cd and Zn availabilities of two sites differing in the soil texture
and origin of pollution was adopted i.e. the site of Metaleurop (North of France) and the site
of Pierrelaye (Paris Region). They differed in the degree of metal pollution (for Cu,
Pb, Cd and Zn) and in the quantity and nature of organic matter (different C/N
values). The samples used for this study involved the soils under annual crops and
the perennial crop i.e. miscanthus. We investigated the trace metal availabilities
of the soils using different single extraction protocols involving chemical metal
extractions with EDTA, DTPA and NH4NO3 at equilibrium and kinetic EDTA
extractions.
The results for the soil under miscanthus compared to annual crop soil showed that single
extraction schemes using chelating agents like EDTA and DTPA, however, failed to
show if the metal availability can be impacted by land use. The differences in metal
availability in the soils under miscanthus and annual crops were highlighted by
the weaker extractant NH4NO3 and by kinetic extractions using EDTA. For the
Metaleurop site, a trend of decrease in Cd and Zn availability in the soil under
perennial miscanthus crop compared to the soil under annual crop was observed. For
the organic matter rich sandy soils of Pierrelaye labile Zn increased while Cd was
decreased. These results showed little impact on trace metal availabilities at the
earlier stage of changes in land use (3 years after conversion). However, on longer
terms, the impact can be more remarkable. The study also highlighted the efficacy
of the use of combination of metal availability assessment approaches instead of
relying on single approaches. In addition the type of changes being occurred in metal
availability can be predicted using combined extraction approaches because the
mechanisms behind each extraction scheme and their target metal pools being different. |
|
|
|
|
|
|