Molecular Markers and Trace-Metals as Indication of Biomass Combustion in Central Amazon Sediments

1. Molecular Markers and Trace-Metals as Indication of Biomass Combustion in Central Amazon Sediments Tereza Cristina Oliveira Angela Wagener e Arthur Scofield tereza.cristina@piatam.org.br

2. Objectives and Methods • Characterization of hydrocarbons in sediments of Solimões River and associated lakes prior to oil exploration. • Base line and diagnostic origin. • Surface sediment sampling in Jun/2005 (wet period) and Nov/2005 (dry period) + cores sediment in 3 lakes. • Molecular markers in saturated and aromatic fractions, 38 PAH, trace-metals, ancillary data. • GC-MS for organics, ICPMS for metals and TOC for organic carbon.

3. 6LB 6LA 1LA 1LB 2LB 2LA Araçá Lake Preto Lake Baixio Lake Study Area 1L Baixio Lake 2L Preto Lake 3S Solimões River 4P Purus River 4S Solimões River 5L Ananá Lake 5S Solimões River 6L Araçá Lake 7L Maracá Lake 7S Solimões Lake 8LP Puraquê Lake 8S Solimões River 8LC Coari Lake 9L Aruã Lake 9U Urucu River

4. Sampling

5. a (a) C29 \ volts minutes b (b) C30 \ volts MCNR minutes Aliphatic hydrocarbons • Chromatograms: • Coari-Manaus, 1L • 0,82 – 148 mg g‑1 • (b) Industrial area, • IND2 • 45,6 – 1060 mg g‑1

6. Perylene was the major PAH Perylene 70% of ∑PAH

7. Parental and Alkylated PAH – Coari-Manaus Wet Season SPAH = 52 – 774ng g-1 Dry Season

8. 90 80 70 60 50 40 30 20 10 0 mg kg-1 N ACEF ACE F Ph A Fl Py B(a)A Ch B(a)F B(k)Fl B(a)Py Ipy DB(ah)A B(ghi)PER 600 500 400 300 200 100 0 mg kg-1 N C1N C2N C3N C4N F C1F C2F C3F Ph C1Ph C2Ph C3Ph C4Ph Py C1Py C2Py Ch C1Ch C2Ch DBT C1DBT C2DBT C3DBT C1DBT C2DBT C3DBT Parental and Alkylated PAH in Industrial Manaus SPAH = 132 - 4713ng g-1

9. Wood Combustion Motor Emissions Mixed Combustion Biomass Combustion Fl/(Fl + Py) Petroleum Combustion Petroleum Combustion C0/(C0 + C1)FlPy Petroleum Oil 1.7/(1.7 + 2.6)Dimethylphenanthrene Diagnostic Ratios - 1.7/(1.7+2.6)DMPh: a proxi for combustion - Fluoranthene/Pyrene - C0 and C1 homologs of Fluoranthene and Pyrene

10. 13 % 66 % Perylene partly derived from combustion ? • Factorial analysis groups " 3-6 rings PAH” (Fl, BaA, BbFl, BaPy, Pe, IPy, Py) and Corg in fator 1 contributing to 66% of the variance. • Good correlations of Pe and some trace metals that can be emitted during combustion [Cd (r=0,83), Pb (r=0,77), Cu (r=0,79), Zn (r=0,73)] Cd → 0,09 – 1,33 mg g-1 Zn → 24,5 – 147 mg g-1

11. Early diagenesis of PAH seen in a core Confirmed identifying geochemical precursors and

12. Series of insaturated compounds and of recent hopanes in 4SII - hopane Recent + mature hopanes in the industrial area

13. 3SI a-Amirina b-Amirina Cromatogram of ions for aromatical composite demonstration of natural sources

14. Mass spectro (Wolf et al., 1989; Bouloubassi & Saliot, 1993; Abas et al. 1995, Buldizinsk et al. 1997Somoneit, 2005; e Simoneit, 2005;).

15. Conclusions • There are no indication of contamination due to ship traffic or oil activities in Coari-Manaus. This is different in industrial Manaus. • Early diagenesis at high local temperatures and biological activity interferes with PAH typology. • Molecular markers are essential in such cases. • In dry periods biomass burning in the “deforestation arc” migrates north and is recorded in sediments. • Some of the perylene found in sediments may derive from these events. • High fraction of 1.7DMPh in dated core indicate combustion (slash-and-burn) records as early as end 19th century.

16. Obrigada!