Biomonitoring of lead in Antarctic lichens using laser ablation inductively coupled plasma mass spectrometry

Autor(es)

Guerra, Marcelo B. B. ^{[1, 2]} ; Amarasiriwardena, Dulasiri ^[2] ; Schaefer, Carlos E. G. R. ^[3] ; Pereira, Catarinie D. ^[1] ; Spielmann, Adriano A. ^[4] ; Nobrega, Joaquim A. ^[1] ; Pereira-Filho, Edenir R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, UFSCar, Grp Appl Instrumental Anal, Dept Chem, BR-13565905 Sao Carlos, SP - Brazil

^[2] Hampshire Coll, Sch Nat Sci, Amherst, MA 01002 - USA

^[3] Univ Fed Vicosa, Dept Soil Sci, UFV, BR-36570000 Vicosa, MG - Brazil

^[4] Univ Fed Mato Grosso do Sul, UFMS, BR-79080190 Campo Grande, MS - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Analytical Atomic Spectrometry; v. 26, n. 11, p. 2238-2246, 2011.
• Citações Web of Science: 14

Resumo

A method for direct determination of Pb by LA-ICP-MS in lichen samples collected in a heavily anthropogenically impacted area of Maritime Antarctica was developed. The lichen samples were cryogenically ground and digested with nitric acid and hydrogen peroxide. Lead determination by solution-based ICP-MS was validated by the use of 2 certified reference materials. Once the Pb concentrations were measured with adequate accuracy and precision, a method for its direct determination by LA-ICP-MS was developed. The laser ablation parameters were optimized by the use of a Doehlert design matrix. The final optimized conditions were: laser energy (60%), spot size (150 mu m) and repetition rate (10 Hz). Lead concentration of the analyzed lichen samples were plotted against the intensity of the lead isotopes ((208)Pb, (207)Pb and (206)Pb) determined by LA-ICP-MS. Satisfactory linear correlation factors were obtained when (13)C was used as internal standard. Lead distribution profiles in lichen thalli cross-sections were also obtained. By these results, LA-ICP-MS emerges as a potential analytical tool for Pb concentration estimation in lichen samples. Minimum amount of sample required, bioimaging capability, high analytical throughput, and minimization of waste generation are the major analytical features of this approach. The significant differences between the Pb concentration in the lichen samples from the control site (1.12 +/- 0.05 mg kg(-1)) and from the impacted points (mean 5.03 +/- 0.57 mg kg(-1)) permitted qualify these organisms as good biomonitors. Elemental bioimaging of lichens demonstrated that the medulla region of lichen thalli is consistently the main atmospheric lead bioaccumulating lichen tissue. (AU)

• Processo FAPESP: 08/08260-3 - Análises químicas de amostras ambientais da Antártica: determinação espectrométrica de Cd, Cr, Ni e Pb, uso de micro-fluorescência de Raios-X com radiação síncrotron e aplicações de ferramentas quimiométricas
• Beneficiário: Marcelo Braga Bueno Guerra
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 06/59083-9 - Espectrometria de massa acoplada ao plasma induzido: aspectos fundamentais e aplicações
• Beneficiário: Joaquim de Araújo Nóbrega
• Modalidade de apoio: Auxílio à Pesquisa - Temático