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Aging reduces the bioavailability of even a weakly sorbed pesticide (carbaryl) in soil

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dc.contributor.authorAhmad, R.
dc.contributor.authorKookana, R.
dc.contributor.authorMallavarapu, M.
dc.contributor.authorAlston, A.
dc.date.issued2004
dc.description.abstractWe investigated bioavailability and biodegradation of carbaryl (1-naphthyl methylcarbamate) in a soil with a long history of pesticide contamination from a storage facility located at Mamoon Kanjan, Pakistan. Carbaryl is weakly sorbed and generally considered to be easily degradable in soil. Extraction studies revealed that 49% of the total carbaryl in soil (88.0 mg kg(-1)) was not water-extractable and also not bioavailable, as demonstrated by inoculation of the contaminated soil with a carbaryl-degrading, mixed bacterial culture. Inoculation of the contaminated soil with the carbaryl-degrading culture showed that the bacteria were capable of degrading only the available (i.e., water-extractable) fraction of the pesticide. When the soil was pulverized in a ball mill to enhance the release of residue, an additional 19% of the carbaryl became bioavailable. A significant proportion of residue (approximately 33%) remained unavailable. The long (>12 years) contact time between the pesticide and soil (i.e., aging), allowing possible sequestration into soil nanopores and the organic matter matrices, is suggested to have rendered the pesticide unavailable for microbial degradation. High concentration (88.0 mg kg(-1)) in soil facilitated its persistence and sequestration. Results from the present study demonstrate that even a weakly sorbed and easily degradable pesticide, carbaryl, is effectively sequestrated in soil with time, rendering it partly inaccessible to microorganisms and affecting the bioavailability of the compound.
dc.identifier.citationEnvironmental Toxicology and Chemistry, 2004; 23(9):2084-2089
dc.identifier.doi10.1897/03-569
dc.identifier.issn0730-7268
dc.identifier.issn1552-8618
dc.identifier.orcidKookana, R. [0000-0002-0477-3284]
dc.identifier.urihttps://hdl.handle.net/11541.2/114360
dc.language.isoen
dc.publisherSETAC Press
dc.rightsCopyright status unknown
dc.source.urihttps://doi.org/10.1897/03-569
dc.subjectCarbaryl
dc.subjectaging
dc.subjectbioavailability
dc.subjectbiodegradation
dc.subjectsequestration
dc.subjectPseudomonas
dc.subjectInsecticides
dc.subjectSoil Pollutants
dc.subjectPesticide Residues
dc.subjectSoil Microbiology
dc.subjectAdsorption
dc.subjectTime Factors
dc.subjectPakistan
dc.subjectBiodegradation, Environmental
dc.titleAging reduces the bioavailability of even a weakly sorbed pesticide (carbaryl) in soil
dc.typeJournal article
pubs.publication-statusPublished
ror.mmsid9915913487801831

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