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Long-term TNT and DNT contamination: 1-D modeling of natural attenuation in the vadose zone: case study, Portugal

dc.contributor.authorAmaral, Helena I. F.
dc.contributor.authorGama, Ana Cláudia
dc.contributor.authorGonçalves, Cláudia
dc.contributor.authorFernandes, Judite
dc.contributor.authorBatista, Maria João
dc.contributor.authorAbreu, Manuela
dc.date.accessioned2017-04-07T15:57:38Z
dc.date.available2017-04-07T15:57:38Z
dc.date.issued2016-07
dc.description.abstractThe vadose zone of a trinitrotoluene (TNT) and dinitrotoluene (DNT) contaminated site was investigated to assess the mobility of those explosives under natural conditions. Located in the left margin of the River Tejo Basin, Portugal, the site is located on unconsolidated sediments. Wastewaters associated with the 50-year explosives production were disposed in excavated ponds, from where water would infiltrate and pollute the unsaturated and saturated parts of the local aquifers. Two boreholes were drilled to 9 m depth in such a former waste pond to investigate the contaminant's fate in the vadose zone. Sediment samples were taken every 1-2 m for analysis of the polynitroaromatics (p-NACs) and organic volatile compounds, pH, organic carbon content, cation exchange capacity and grain size analysis. The main contaminant was TNT representing >70 % of the total p-NACs concentration that peaked approximately 7 mg/kg in one borehole, even if the median in both boreholes was of similar to 1 mg/kg. DNT was 4-30 % of the total p-NACs and nitrotoluene (NT), up to 5 %. No other (volatile) organic compound was detected. The predominance of TNT as the main contaminant implies that any natural mass reduction has been inefficient to clean the site. Several 1-D model simulations of p-NACs cleaning of the vadose zone under natural conditions indicated that the most probable scenario of combined advection and partitioning will only remove TNT after 10's of years, whereas DNT and NT will hardly be removed. Such low concentrations and long times for the p-NACs removal, suggest that by now those compounds have been washed-out to a level below standard limits.
dc.identifier.doi10.1007/s12665-015-4937-y
dc.identifier.issn1866-6280
dc.identifier.urihttp://hdl.handle.net/10400.1/9771
dc.language.isoeng
dc.peerreviewedyes
dc.publisherSpringer Verlag
dc.relationDelineating new sampling, analysing and modelling strategies for assessing the Contamination of soil and gRoUnDwatEr by organic compounds (CRUDE)
dc.relation.isbasedonWOS:000370239800089
dc.titleLong-term TNT and DNT contamination: 1-D modeling of natural attenuation in the vadose zone: case study, Portugal
dc.typejournal article
dspace.entity.typePublication
oaire.awardTitleDelineating new sampling, analysing and modelling strategies for assessing the Contamination of soil and gRoUnDwatEr by organic compounds (CRUDE)
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/3599-PPCDT/PTDC%2FCTE-GEX%2F72959%2F2006/PT
oaire.citation.endPage89
oaire.citation.issue1
oaire.citation.startPage89
oaire.citation.titleEnvironmental Earth Sciences
oaire.citation.volume75
oaire.fundingStream3599-PPCDT
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.nameFundação para a Ciência e a Tecnologia
rcaap.rightsrestrictedAccess
rcaap.typearticle
relation.isProjectOfPublication1b347192-71c3-451c-a4b7-6a36e5225060
relation.isProjectOfPublication.latestForDiscovery1b347192-71c3-451c-a4b7-6a36e5225060

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