Molecular Markers and Trace-Metals as Indication of Biomass Combustion in Central Amazon Sediments Tereza Cristina Oliveira Angela Wagener e Arthur Scofield

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.

Study Area 1LB 1LA Baixio Lake 2LB 2LA Preto Lake 6LB 6LA Araçá Lake 1L Baixio Lake 2L Preto Lake 3SSolimões River 4PPurus River 4SSolimões River 5LAnaná Lake 5SSolimões River 6LAraçá Lake 7LMaracá Lake 7SSolimões Lake 8LPPuraquê Lake 8SSolimões River 8LCCoari Lake 9LAruã Lake 9UUrucu River

Sampling

Chromatograms: (a) (a)Coari-Manaus, 1L 0,82 – 148  g g ‑ 1 (b) Industrial area, IND2 45,6 – 1060  g g ‑ 1 C 29 \ (a) volts minutes a (b) volts minutes MCNR C 30 \ b Aliphatic hydrocarbons

Perylene was the major PAH 70% of ∑PAH Perylene

WetSeason DrySeason Parental and Alkylated PAH – Coari-Manaus  PAH = 52 – 774 ng g -1

Parental and Alkylated PAH in Industrial Manaus C1DBT C2DBT C3DBT  g 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  g 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  PAH = ng g -1

- 1.7/( )DMPh: a proxi for combustion a proxi for combustion - Fluoranthene/Pyrene - Fluoranthene/Pyrene - C 0 and C 1 homologs - C 0 and C 1 homologs of Fluoranthene and of Fluoranthene and Pyrene Pyrene Motor Emissions Mixed Combustion Wood Combustion Biomass Combustion Petroleum Combustion Petroleum Combustion Petroleum Fl/(Fl + Py) C 0 /(C 0 + C 1 )FlPy 1.7/( )Dimethylphenanthrene Oil Diagnostic Ratios

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. 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)] 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)] 13 % 66 % Cd → 0,09 – 1,33  g g -1 Zn → 24,5 – 147  g g -1

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

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

Cromatogram of ions for aromatical composite demonstration of natural sources 3S I -Amirina-Amirina

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

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

Obrigada!