INDIRECT DETECTION OF LIQUID HYDROCARBON LEAKAGES ON CONTAMINED SOIL-VEGETATION SYSTEMS THROUGH REFLECTANCE AND IMAGING (PROSPECTIR-VS)

SPECTROSCOPY: A POTENTIAL TOOL FOR EXTENSIVE PIPELINE MONITORING

Carlos Roberto Souza Filho1, Lucíola Magalhães1; Giuliana Quitério1 Marcos Nopper1 , Teodoro Almeida2 ; Wilson Olveira3; Lis Rabaco3; Renato Rocha3

University of Campinas, Campinas, Brazil 1

University of São Paulo, São Paulo, Brazil2

Petrobras S.A./CENPES, Rio de Janeiro, Brazil3

LAPIG

INTRODUCTION & OBJECTIVES

• Current methods of pipeline monitoring poses hindrances to the early detection of small hydrocarbon spills.

• Assuming that liquid fuels (gasoline and diesel) are potential vegetation stressors, this study investigates the spectral characteristics of agricultural crops subjected to daily contamination of liquid hydrocarbons, using reflectance spectroscopy (portable FieldSpec Hi-Res sensor, with 2150 bands in the VNIR-SWIR range) and imaging spectroscopy (airborne ProSpecTIR-VS hyperspectral sensor, with 357 bands in the VNIR-SWIR range).

• The study comprises both greenhouse and real scale experiments, where we will seek the probable impacts of hydrocarbon contamination through spectral changes in 5 plant species commonly present in the vicinity of pipelines, particularly in Brazil, with focus on Brachiaria brizantha (“grass”) and Neonotonia wightii (“soybean”)

THE EXPERIMENTS

THE EXPERIMENT• 2 SCALES: small scale experiment (“lysimeter”) & macro scale (real, field scale). • 3 types of spectral analysis

– Leaf (lysimeter) (FieldSpec Hi-Res – ASD)– Canopy (macro scale experiment) (FieldSpec Hi-Res – ASD)– Canopy (airborne hyperspectral survey) (357 bands at 5nm resolution -

ProSpecTIR-VS)

• 2 contaminants: diesel (DSL) and gasoline (GSL)

THE EXPERIMENT Vegetation Species

• Resistance (i.e. plagues) and commonness • Agronomic importance • Extensive occurrence along pipelines

Neonotonia wightii“soybean”

Brachiaria brizantha“perenial grass”

THE EXPERIMENTLysimeters

THE EXPERIMENTLysimeters

THE EXPERIMENTLysimeters

LYSIMETERSBrachiaria brizantha (grass)

Brachiaria brisantha

• Experiments – timeframes of 5 months.• Leakage – begininning with plantation • Periodical spectral measuments• Peridiocal leakages• Controlled irrigation • Samples collected for biochemical analysis

by the end of the experiment

*Soil Water Holding Capacity

Measument Time-days Vol-HC-ml SWHC*

LISYMETERNeonotonia wightii (soybean)

Neonotonia wightii

• Experiments: timeframes of 3 months• Leakage – begininning 30 days after

plantation • Periodical spectral measuments• Peridiocal leakages (once per 15

days)• Controlled irrigation (automatically)• Samples collected for biochemical

analysis by the end of the experimentMeasument Time-days Vol-HC-ml SWHC*

THE EXPERIMENTMacro (real) scale

HC resistant matle to avoid ground contatmination Hydrocarbon leakage system

THE EXPERIMENTMacro (real) scale

THE EXPERIMENTMacro (real) scale

Five plant species: Brachiaria brizantha (BR) (“grass”), Neonotonia wightii (SJ) (“soybean”), Saccharum spp (CA) (“sugar cane”), Phaseolus vulgaris (FE)

(“bean”), and Zea mays (MI) (“maize”) .

THE EXPERIMENTMacro (real) scale

• Experiments – timeframe of 2 (May-April/2010)

• Periodical spectral measuments of both leaf and canopy

• Peridiocal leakages – daily leakage of 200l of HCs

• Controlled irrigation • Samples collected for biochemical

analysis every week

APRIL MAY

THE EXPERIMENTCanopy Measuments from Specifically-designed Platform

Platform for canopy spectral measuments

- FieldSpec High Resolution (ASD);- Sampled area: 30cm;- 10 samples per parcel.

• Data acquisition: MAy, 18th, 2010• 14 days after HC leakage began • 2600 L of HCs in the system = 130L per parcel

• ProsSpecTIR Spectral resolution: VIS/NIR:125 channel; SWIR:232 channel• Spatial resolution: 60 cm

THE EXPERIMENTProSpecTIR Airborne System

RESULTSRESULTS

LYSIMETERSBrachiaria brizantha

CTR DSL GSL CTR

M1 (45 days/200mL)

M4 (93 days/250mL)

M7 (145 days/300mL)

Morphological alterations

M1 = 35 days/0mL

M4 = 64 days/100mL

M7 = 99 days/200mL

Canopy Roots

Leaves

GSL CTR DSL

Morphological Alterations

LYSIMETERSNeonotonia wightii

GSL CTR DSL

PL

AT

FO

RM

- D

oss

el -

LYS

IME

TE

R-

Lea

ves

-

GRASS SOYBEAN

MACRO SCALE EXPERIMENT CSe RATIO (R694/R760 )

Spectral Measument

Spectral Measument Spectral Measument

Spectral Measument

GR

AS

SS

OY

BE

AN

Comparative photos of plant canopies when spectral alterations are perceived through CSe ratios

GSL/M4 CTR/M5 DSL/M4

GSL/M5 CTR/M5 DSL/M4

MACRO SCALE EXPERIMENT

LYSIMETERSBrachiaria brizantha

SHORTWAVE INFRARED (SWIR) REGION

Three patterns are observed at:

• 2477nm ; 2485 - 2495nm e 2440 - 2485nm

Co

nti

nu

um

-re

mo

ve

d r

efl

ec

tan

ce

Wavelength (nm)

Poly-Saccharides

LYSIMETERSNeonotonia wightii

SHORTWAVE INFRARED (SWIR) REGION

Spectral pattern at 2062 nm >> association with leaf biochemical analysis (rise in monosaccharides (“sugar”) content)

Wavelength (nm)

No

rma

lis

ed

av

era

ge

(%

in

re

lati

on

to

CT

R)

monosaccharides

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

• Two step algorithm (Almeida & Souza Filho, 2004; 2008):• 1) Production of 15 spectral indices > enhancement of specific spectral signatures

of vegetation properties • 2) Principal Component Analysis applied to three sub-stes of spectral indices

Indices applied to vegetation analysis Group Index Spectral Formula ProSpecTIR channels

-CarotenAntocianina-Chlorophyllb-ChlorophyllCarotenoidsSIPICSe

NDVIVOG1WBIMAC

Leaf waterLigninCelluloseNitrogen

CTR

GSL

DSL

CSe Ratio

Degree of stress based on the CSe (694nm/760nm) ratio

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

Degree of stress

CTR

GSL

DSL

PC1 - Group 1 (VNIR)

a-Chlorophyll, b-Chlorophyll, Carotenoids

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

Degree of stress

Eigenvector matrixEigenvector a-caroten antocian. a-Chlrop b-Chlorop Caroten. SIPI CSe

PC1 - Group 2 (NIR)

NDVI, VOG1 e WBI

CTR

GSL

DSL

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

Eigenvector

Eigenvector matrix

Degree of stress

PC2 – Group 3 (NIR/SWIR)

Lignin

CTR

GSL

DSL

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

Degree of stress

Eigenvector Leaf Water Lignin Cellulose Nitrogen

RGB Colour Composition

R: PC1 - Group 1 (VNIR)G: PC1 - Group 2 (NIR) B: PC2 - Group 3 (NIR/SWIR) 

CTR

GSL

DSL

INFORMATION EXTRACTION OF HYPERSPECTRAL DATA (PROSPECTIR VS)

PC1Group 1

PC1Group 2

PC2Group 3

DISCUSSIONS & CONCLUSIONSDISCUSSIONS & CONCLUSIONS

DISCUSSIONS & CONCLUSIONS

The proposed methodology showed a high correlation between canopy spectral measurements taken at close range with the FieldSpec Hi-Res sensor and from the airborne ProspecTIR-VS sensor.

It was possible to characterize the reflectance of leaves grown in soils contaminated by low concentrations of gasoline and diesel and differentiate them from plants grown on soil without HCs.

The use of selected vegetation indices showed a high correlation with the behavior of vegetation stressed by the presence of HCs in all three scales of observations.

The spectral changes were similar among species but more prominent for gasoline (GSL) than diesel (DSL), occurring at different timeframes and under different doses of HCs

The results confirm the higher toxicity of gasoline for all selected crops.

The development of this work supports the possibility to preserve certain crops along pipelines that can be used as a bio-indicator of small leakages and the types of crops more susceptible to stress-induced leakage.

It also makes a first step on the establishment of the initial timing (i.e., exposure time and volume of injected hydrocarbons) when the contamination effects are more perceptible remotely.

Thank you !

Geosciences Institute

University of Campinas (UNICAMP)

www.ige.unicamp.brwww.ige.unicamp.br/

sdm

beto@ige.unicamp.br

LAPIG