Use of Biomarkers Indices in a Sediment Core to Evaluate Potential Pollution Sources in a...

This article appeared in a journal published by Elsevier. The attachedcopy is furnished to the author for internal non-commercial researchand education use, including for instruction at the authors institution

and sharing with colleagues.

Other uses, including reproduction and distribution, or selling orlicensing copies, or posting to personal, institutional or third party

websites are prohibited.

In most cases authors are permitted to post their version of thearticle (e.g. in Word or Tex form) to their personal website orinstitutional repository. Authors requiring further informationregarding Elseviers archiving and manuscript policies are

encouraged to visit:

http://www.elsevier.com/authorsrights

Author's personal copy

Chemie der Erde 73 (2013) 555 563

Contents lists available at ScienceDirect

Chemie der Erde

jou rn al homepage: www.elsev ier .de /chemer

Use of biomarkers indices in a sediment core to evaluate potentialpollution sources in a subtropical reservoir in Brazil

Juan Sneza,, Sandro Froehnerb, Filipe Falcob

a Graduate Program in Water Resources and Environmental Engineering, Federal University of Parana, 81531-990 Curitiba, Parana, Brazilb Environmental Engineering Department, Federal University of Parana, 81531-990 Curitiba, Parana, Brazil

a r t i c l e i n f o

Article history:Received 29 November 2012Accepted 24 July 2013

Keywords:Biogenic decompositionBiomarkersCarbon preference indexn-AlkanesPAHsOrganic matterSediment pollutionSubtropical reservoir

a b s t r a c t

The presence of PAHs, n-alkanes, pristane, and phytanes in core sediment from the Vossoroca reser-voir (Parana, southern Brazil) was investigated. The total concentration of the 16 PAHs varied from15.5 to 1646 g kg1. Naphthalene was present in all layers (3.3474.0 g kg1). The most abun-dant and dominant n-alkanes were n-C15 and n-C36, with average concentrations of 198.1 46.8 and522.9 167.7 g kg1, respectively. Lighter n-alkanes were distributed more evenly through the layersand showed less variation, specially n-C9, n-C12, and n-C18, with average concentrations of 14.6 3.0,31.6 1.9, and 95.0 5.2 g kg1, respectively; heavier n-alkanes were more unevenly distributed.

The study of the biomarker ratios indicates a slight inuence from the nearby Highway BR 376: depositof sediments coming from the pavement and sources of pyrolytic origin from the heavy trafc of vehiclesand a gas station close to the sample point. In addition to this, the n-alkanes ratio analysis indicates that theregion receives signicant contribution from higher plants, with low contribution from autochthonousorganic matter origin. Identied PAHs suggest pyrogenic sources formed during the pyrolysis of fossilfuels and direct inuence from the heavy trafc from the nearby highway. The DBahA was found to berelated to the contribution of particulate pavement, but only in signicant concentrations after 15 cmdepth. Sediment fractions seem to be oxic, and the absence of phytane can be explained by severalperiods of bioturbation and tidal. In general, when compared with other studied sediments, the areaseems low-polluted.

2013 Elsevier GmbH. All rights reserved.

1. Introduction

The role of sediments in aquatic ecosystems is indispensible.This environmental matrix can store nutrients, organic matter, andpollutants, sometimes replacing these substances in the water col-umn. Despite the importance of their role, since the middle of thelast century, sediments have been subjected to degradation andheavy pollution from diverse toxic chemicals like pesticides, heavymetals, endocrine disruptors, polychlorinated biphenyl (PCBs),polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons(AHC) from fuel and derivates, partly due to rise in oil consumptionand a heavy use of chemicals in our modern society, altering their

Abbreviations: CPI, carbon preference index; HMW, high molecular weight;LMW, low molecular weight; Paq, proportion of aquatic plants; TARHC, terrigenousaquatic ratio hydrocarbon.

Corresponding author at: Graduate Program in Water Resources and Environ-mental Engineering, Federal University of Parana, Caixa Postal 19011, Jardim dasAmricas, CEP 81531-990 Curitiba, Parana, Brazil. Tel.: +55 41 33613210;fax: +55 41 33613143.

E-mail address: [email protected] (J. Snez).

natural function within ecosystems (examples Chen et al., 2004;Venturini et al., 2008; Froehner et al., 2009; de Souza et al., 2011).

The quality of the sediments may be evaluated through thecontent of AHC and PAHs, which are the two major classes of com-pounds found in oil. Therefore, they are used as chemical markersto identify potential sources of environmental pollution from crudeoil, gasoline, and diesel (Yunker et al., 1999; Savinov et al., 2003;Lee et al., 2005; Liu et al., 2008; Froehner et al., 2012). Of these,the PAHs may enter the environment from different sources suchas pyrolytic, petrogenic, oil spills, and biogenic processes. Pyrolyticorigin is attributed to incomplete combustion of recent and fos-sil organic matter (Yunker et al., 2002a) at higher temperatureswhereas in the petrogenic process, organic matter matures slowlyunder geochemical gradient (Wan et al., 2005). The contribution ofPAHs by microorganisms is considered small and has not yet beenfully described (Soclo et al., 2000; Bzdusek et al., 2004; Opueneet al., 2007).

Ratios between some PAHs assisted in the investigation of possi-ble sources of petrogenic or pyrolytic PAHs sources. Stable isomersusually originate from petrogenic sources, while unstable isomersare of pyrolytic origin (Budzinski et al., 1997; Yunker et al., 2002a,b).The presence of high concentrations of PAHs having more than four

0009-2819/$ see front matter 2013 Elsevier GmbH. All rights reserved.http://dx.doi.org/10.1016/j.chemer.2013.07.005


556 J. Snez et al. / Chemie der Erde 73 (2013) 555 563

aromatic rings is indicative of the formation of the compoundsduring pyrolysis of fossil fuels (Gogou et al., 2000). The distribu-tion of PAHs depends on the temperature of the pyrolytic reactionthat yields products governed by thermodynamic properties at lowtemperatures (catagenesis) and by kinetic characteristics (Yunkeret al., 1999, 2002a) at elevated temperatures (pyrolysis).

An important group belonging to the AHC is the n-alkane hydro-carbons, which are linear, unbranched chains with saturated bonds,that may be synthesized by most living organisms: terrestrial(bacteria and higher plants) or aquatic (phytoplankton and zoo-plankton). Higher plants retain water in their leaves by synthesizingepicuticular waxes having long-chain n-alkanes ranging from n-C25 to n-C35, while algae synthesize short-chain n-alkanes rangingfrom n-C15 to n-C21. n-Alkanes dominate the group of saturatedorganic compounds present in the organic matter fraction of sed-iments. In both terrestrial and aquatic organisms, the synthesis ofn-alkanes having odd number of carbons is predominant (Volkmanet al., 1980), which may be rationalized from their biosyntheticpathway involving enzymatic decarboxylation from fatty acidsgenerally having an even number of carbon atoms (Killops andKillops, 2005). Natural sources of n-alkanes from continental ori-gin are mainly cuticular wax derivatives of vascular plants, suchas mangroves. The n-alkanes present in petroleum do not showany predominance with respect to the number of carbons in theirchains and cannot be related, which may be used as an indica-tive of contamination (Simoneit, 1993). Anthropogenic sources aremainly associated with industrial processes, pyrolysis of fossil fuels,oil spills and derivatives and their presence in lake sediments ismainly attributed to biogenic sources that originate from two majorgroups of plants, divided according to their biochemical composi-tion (Lichtfouse et al., 1997) as non-vascular plants, with little orno cellulose and lignin, with high protein content and rich in nitro-gen (e.g. phytoplankton) and vascular plants having a large contentof woody tissue, with abundant hydrocarbon waxes (e.g. grasses,shrubs, trees and ground emergent macrophytes in lakes).

In the last decade, several studies involving the quantication ofn-alkanes for reconstruction of environmental conditions and pastscenarios in marine and lacustrine environments (e.g. de Souza,2011; Froehner et al., 2012) were carried out. Ratios of n-alkaneswere used to identify sources of organic matter and petrogenic con-tamination from anthropogenic activity in sediments in the aquaticenvironment (i.e. Bray and Evans, 1961; Colombo et al., 1989;Steinhauer and Boehm, 1992; Bourbonniere and Meyers, 1996).

The principal objective of this study is to determine the contentof PAHs and n-alkanes in a sediment core and to evaluate importantrelated biomarker indices, in order to assess the potential sources ofpollution. Furthermore, the extent of the organic matter producedby the aquatic system itself as against terrigenous contribution inthe sediments would also be evaluated. These results accompaniedby other related investigations, could help understand the impactof neighboring human activities on the sediments of the Vossorocareservoir.

2. Methods

2.1. Study area

The Vossoroca reservoir spanning over a 5.1 km2 ooded area,is located in the central region of the First Parana Plateau in theSerra do Mar region, 80 km from Curitiba, the capital of the ParanaState, in southern Brazil. The reservoir comes under the Environ-mental Protection Area of Guaratuba and is surrounded by steepareas covered with vegetation and includes a few marshy stretches.The impoundment is part of Vossorocas Chamine HydroelectricComplex installed on the So Joo River, under the municipality of

Tijucas do Sul, Parana State. The dam is intended to retain water inorder to generate electricity in the Chamine Plant, located 12 kmupstream of the Salto do Meio reservoir (Silveira, 2005; Kanteket al., 2009).

The topography of the region is very rugged having domain ofCombisol type of soil shallow soils, drainage and limited agricul-tural use. The native vegetation is preserved and has a biodiversitytypical of the Atlantic Forest (Forest ombrophilous Montana), withpresence of Araucaria Forest. The type of climate is Cfb HumidSubtropical mesothermal, with cool summers and frequent frosts,with no dry season. The annual temperature averages less than22 C in the warmer months and below 18 C in the colder monthswhile the annual average temperature is 17 C. Rainfall is between1330 and 1400 mm and the relative humidity is 85%. The hydricindex is between 60 and 100, without water decit. The So JooRiver is the main tributary of the reservoir, and ows across urbanregions and areas predominantly covered by rainforests.

The reservoir shows thermal stratication and dissolved oxygenin warm periods and destratication in low temperature months,with characteristics of hypoxia most of the time. The reservoirhas a natural tendency to cyanobacteria blooms. High density ofthese organisms is favored due to higher temperatures in the upperlayers of the reservoir, column stratication of water and high resi-dence time in the reservoir (121 days, lentic environment). Localcyanobacteria predominate over other groups of phytoplanktonalgae.

Commercial agriculture, not signicant in the region, isrestricted to small portions where the soil can meet the high expec-tations of productivity and transportation is facilitated. The tourismactivity (leisure farms with open barbeques, boats, sheries, etc.)is a growing activity (de Souza, 2011).

2.2. Sampling and sample treatment

The sampling site was located in the proximity of the BR 376highway (Rod. Henrique Herwig) leading to the Vossoroca reser-voir, 5 m to the left of the road, which passes over the reservoir(Fig. 1). The level of the reservoir was low due to a long droughtperiod. The sample was collected in a 2 m PVC tube having a 3 in.diameter. A sediment core of 50 cm was collected that had verypasty consistency. The core was frozen and subsequently fraction-ated into 5 cm pellets. Each fraction was separately dried in an ovenat 40 C. The dried sediment was ground with a mortar and pestleaid.

Sedimentation rate was calculated in the order of 0.0375 m/yearat an error of 10%, giving approximately 1.3 years for every 5 cm ofdeposition.

2.3. Analysis

The methodology used by Froehner et al. (2011) was followedwith some minor modications. Upon drying the pellets, each onewas homogenized and sieved. In a 50-mL beaker, 10 g of a dried andsieved sample was placed, to which 20 mL of hexane was added.Further, the beaker was placed in an ultrasound bath for 15 min inorder to extract the analyte from the sediment. The supernatantand remaining solvent were ltered and separated and procedurewas repeated with 20 mL of 1:1 hexane:dichloromethane followedby extraction with 20 mL of dichloromethane. The three extractswere mixed and the solvent was distilled out on a rotary evapo-rator until dryness. 3 mL of hexane was added to the dried extractthat was stirred for a few seconds with ultrasound. Then, the solu-tion was added to a previously conditioned column for cleaning upwith hexane and dichloromethane. Each fraction was again evapo-rated until dryness in a rotary evaporator and redissolved in 1 mL


J. Snez et al. / Chemie der Erde 73 (2013) 555 563 557

Fig. 1. Brazil map showing the localization of the Parana State and the Vossoroca Reservoir (a). Part of the Vossoroca Reservoir showing the Highway BR 375, the samplingsite (arrow) and, in the circle, the gas station (b).

of dichloromethane. Then, the solution was placed in a vial for itsanalysis by GC with FID.

3. Results and discussion

3.1. PAHs

Sixteen standard PAHs were analyzed (Table 1) of whichsix compounds, namely, acenaphthene, benzo[a]anthracene,benzo[k]uoranthene, benzo[a]pyrene, indene[1,2,3-cd]pyreneand benzo[ghi]perylene, were not detected in any fraction of thesediment core. Fluorene was only detected in the 4550 cm frac-tion. Naphthalene was present in all the layers (3.3474.0 g kg1),followed by anthracene (1.4610.0 g kg1) and followed by uo-ranthene (4.8414.9 g kg1) having two, three and four benzene

rings respectively. The last one is mainly from a pyrolytic source,while the rst two are from petroleum. The total concentrationof the 16 PAHs (PAH) varied from 15.5 to 1,646 g kg1 withinthe 510 cm and 3035 cm layers, respectively. In general, withsome exceptions, concentration of individual PAHs was verylow in comparison to those found in urban and industrializedregions (e.g. Colombo et al., 1989; Doskey and Andren, 1991;Medeiros and Bcego, 2004; Lee et al., 2005; Banger et al., 2010).The upper layers, between 0 and 15 cm contained relativelylow to medium concentrations of PAHs (15.5122 g kg1),while the lower layers between 15 and 50 cm comprised ofmedium to high (2151646 g kg1) concentrations of PAHs.An interesting feature was the dominance of naphthalene, ace-naphthylene, anthracene and uoranthene (8.260.8%), possiblyfrom unburned fossil fuels in the fresh topmost layer (015 cm)



Table 1Individual concentration (g kg1 dry sediment) and important indices of PAHs in the sediment core layers.

Sediment core layer (cm)

05 510 1015 1520 2025 2530 3035 3540 4045 4550

Naphthalene 74.0 5.95 74.0 4.29 3.34 3.78 6.67 28.2 4.22 6.76Acenaphthylene 37.7 bdl 37.7 36.5 35.2 bdl bdl bdl bdl bdlAcenaphthene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlFluorene bdl bdl bdl bdl bdl bdl bdl bdl bdl 5.17Phenanthrene bdl bdl bdl bdl 6.45 3.83 bdl bdl 4.41 6.55Anthracene 10.0 4.71 10.0 bdl 1.46 1.52 6.27 8.51 bdl 9.13Fluoranthene bdl 4.84 bdl 8.94 14.9 9.68 6.86 bdl 8.83 9.87Pyrene bdl bdl bdl bdl 13.2 bdl bdl bdl 6.63 8.48Chrysene bdl bdl bdl 6.84 1.43 6.40 bdl 9.7 7.46 1.68Benzo[a]anthracene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlBenzo[b]uoranthene bdl bdl bdl 158 101.8 bdl bdl 488 137 211Benzo[k]uoranthene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlBenzo[a]pyrene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlIndene[1,2,3-cd]pyrene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlBenzo[ghi]perylene bdl bdl bdl bdl bdl bdl bdl bdl bdl bdlDibenzo[ah]anthracene bdl bdl bdl bdl 783 1028 1627 bdl 1269 bdlPAHs 122 15.5 122 215 961 1053 1646 534 1438 259Ant/Ant+Phe 1 1 1 a 0.1847 0.284 1 1 a 0.582Flt/Flt+Pyr a 1 a 1 0.529 1 1 a 0.571 0.537BaA/BaA+Chry a a a 0 0 0 a 0 0 0IP/IP+BghiP a a a a a a a a a a

Phe/Ant 0 0 0 a 4.414 2.515 0 0 a 0.718Flt/Pyr a a a a 1.127 a a 1.331 1.164BaA/Chry a a a 0 0 0 a 0 0 0LMW/HMW a a a a 0.227 0.0245 0.012 a 0.133 a

bdl, below detection limit.a Calculations not made due to being divided by zero.

which was in contrast to the overbearing presence of PAHs hav-ing four and ve aromatic rings and a pyrolytic origin, namely,benzo[b]uoranthene (9.698.8%) and dibenzo[a,h]anthracene(81.598.8%) in the lower layers (1550 cm).

While stable isomers are usually produced from petrogenicsources, the unstable isomers are of pyrogenic origin (Budzinskiet al., 1997) and the predominance of high concentrations of PAHshaving more than four aromatic rings points to their formationduring pyrolysis of fossil fuels (Gogou et al., 2000).

Interestingly, in all layers where it was possible to evaluatethe ratios of PAHs (Yunker et al., 2002a, 2002b), the values indi-cated a pyrolytic origin (Gschwend and Hites, 1981; Soclo et al.,2000). The An/An+Phe, Flt/Flt+Pyr, and Flt/Pyr indices showed val-ues above 0.10, 0.5 and 1, respectively. Meanwhile, the Phe/Antand LMW/HMW presented ratios below 10 and 1, respectively. Incontrast, the BaA/BaA+Chry and BaA/Chry presented ratios below20 and 0.4, more specically zero values in both the cases, whichsuggests petrogenic origin of PAHs (Gschwend and Hites, 1981;Yunker et al., 2002a, 2002b). Notably, BaA was not detected (val-ues below the detection limit). Further, the prepared crossplotsbetween Ant/Ant+Phe and Phe/Ant vs. Flt/Flt+Pyr ratios (Fig. 2)revealed that, in general, sources of PHAs were of pyrolytic ori-gin with a possible small contribution of petroleum (4045 cm)(Gschwend and Hites, 1981; Yunker et al., 2002a, 2002b; Bcegoet al., 2006).

Froehner et al. (2012) studied the presence of PAHs in the sur-cial sediments in the Vossoroca Reservoir. On comparing the PAHsconcentration with our research, some interesting ndings showedup. Acenaphthene, benzo[a]anthracene, benzo[k]uoranthene,benzo[a]pyrene, indene[1,2,3-cd]pyrene and benzo[ghi]perylenewere present in all samples the values for which from our researchwere below detection limit and were not present in any layer. Sim-ilarly, uorene was present only in the deeper core (4550 cm),although it occurred in all samples studied by Froehner et al.In general, the values for other PAHs, particularly in sedimentsclose to the bridge, were several times higher than those foundin our sediment core layers, indicating possible degradation over

time. Comparison of the ratios between PAHs with those reportedby Froehner et al., revealed similar conclusions where the mainsources of PAHs are of pyrolytic origin, especially emissions fromvehicles that cross the bridge. In accordance to literature values, thedibenzo[a,h]anthracene concentrations were relatively high whichcould be attributed to coal tar pavement, considering that the sam-ple site was close to a heavily transited road.

Additionally, there was no report of any important episode ofoil spill registered close to the area of study; however, the samp-ling site being located close to a highway, soot, exhaust gases, oiland petroleum leaks and dust from worn out tires may reach thesite close to the reservoir. The studied zone is not an industrializedone; the main activities are subsistence farming and tourism forleisure (like the burning of coal for barbecues), although these activ-ities are neither extensive nor intensive. In summary, an apparentpredominance of pyrolytic PAHs was observed in the lower lay-ers, while apparently unburned fossil fuels prevailed in the upperlayers.

3.2. n-Alkanes

n-Alkanes bearing eight to forty carbon atoms were evaluatedand their concentrations have been presented in Table 2. n-C8 andn-C10 alkanes were not detected in any layer. n-C15 and n-C36 werethe most abundant and dominant n-alkanes averaging 198 46.8and 523 168 g kg1, respectively in the core while other promi-nent ones were n-C18 and n-C32. In general, the heavier n-alkanesprevailed, in concentration and abundance, over the lighter onesand, although not very clear, odd n-alkanes were slightly dominantover even n-alkanes. Distribution proles of these compounds havebeen shown in Fig. 3.

In Fig. 3, each bar representing a particular chain-length is theconcentration of the specic n-alkane in that layer, from upper(left) to lower (right) layers. The lighter n-alkanes were distributedmore evenly through the layers, particularly n-C9, n-C12 andn-C18 showed less variation, averaging 14.6 3.0, 31.6 1.9 and95.0 5.2 g kg1, respectively, in the core whereas the heavier



Fig. 2. Crossplots of the values Ant/Ant+Phe and Phe/Ant ratios against Flt/Flt+Py ratio for all the layers of the core sediment.

n-alkanes presented a more odd distribution. The predominanceof n-alkanes (Table 3) like n-C36, as well as alkanes of carbon chaingreater than 35, was also observed in bitumen compounds thatact as a binder substance on the pavement, and can therefore be,characteristic of both sources. It is noteworthy that high concen-trations of n-C36 in the sediment in comparison to other chainlengths suggest that the impact is primarily due to the contri-bution of the pavement. On the other hand, n-C15 is associatedwith aquatic algae, plankton and photosynthetic bacteria (Cranwellet al., 1987; Doskey and Andren, 1991) and n-C31 to related grasses

(Cranwell, 1973). Although less abundant, contributions fromn-C27, n-C29 and n-C31 alkanes were noted and possibly arose fromwaxes of higher plants growing nearby (Eglinton and Hamilton,1963, 1967; Cranwell, 1973; Cranwell et al., 1987; Rieley et al.,1991; Meyers, 2003), n-C23 probably from oating and submergedplants (Cranwell, 1984; Ficken et al., 2000), and n-C18 from indige-nous sources, such as bacterial degradation of algae and detritus(Elias et al., 1997; Ekpo et al., 2005).

Analysis of the Carbon Preference Index (CPI) values in thecore revealed that they ranged between 0.35 and 3.99. CPIs values

Fig. 3. Chain-length distribution of n-alkanes from the sediment core. Each bar, for a determined chain-length, is the concentration of this specic n-alkane in that layer,from upper (left) to lower (right) layers. The arrow indicates a bar out of scale, in this case the concentration is 1514 g kg1 (510 cm).



Table 2n-Alkane concentrations (g kg1 dry sediment) in the layers of the sediment core from the Vossoroca Reservoir.

Sediment core layer (cm)

05 510 1015 1520 2025 2530 3035 3540 4045 4550

Prystane 46.6 31.5 21.7 19.4 29.2 30.4 22.8 20.4 33.9 30.4Phytane bdl bdl bdl 1.55 2.87 bdl bdl bdl 7.61 bdln-C8 bdl bdl bdl bdl bdl bdl bdl bdl bdl bdln-C9 13.1 13.1 13.0 14.3 14.4 13.0 22.3 bdl 15.1 13.0n-C10 bdl bdl bdl bdl bdl bdl bdl bdl bdl bdln-C11 3.21 2.67 3.40 12.3 3.80 2.83 3.55 5.50 3.17 2.83n-C12 36.7 30.5 29.4 30.3 31.5 31.3 31.9 31.7 31.3 31.3n-C13 19.4 63.3 83.5 2.50 72.0 0.92 1.02 1.47 85.9 0.92n-C14 42.8 52.4 35.6 35.9 36.8 37.3 60.4 95.2 47.5 37.3n-C15 253 200 229 245 216 218 135 127 140 218n-C16 65.9 40.2 31.3 23.5 23.5 62.3 102 19.1 18.6 62.3n-C17 bdl 24.3 bdl bdl bdl bdl 19.0 15.68 bdl bdln-C18 102 97.0 bdl 93.5 90.7 89.8 102 100 90.7 89.8n-C19 10.9 20.4 7.99 10.7 11.2 19.0 22.1 11.4 1.46 19.0n-C20 7.00 13.7 4.23 5.60 4.87 7.50 3.00 1.42 97.7 7.5n-C21 105 9.19 10.9 27.7 23.2 2.93 2.69 bdl 55.0 2.93n-C22 11.8 16.3 5.88 6.78 8.71 14.6 10.2 13.6 10.6 14.6n-C23 bdl bdl bdl 18.0 31.1 55.1 bdl 97.2 50.4 55.1n-C24 1.40 22.9 17.9 2.70 24.5 13.6 36.0 10.1 37.2 13.6n-C25 bdl 11.0 7.61 2.80 0.31 8.79 bdl bdl bdl 8.79n-C26 544 44.8 18.6 14.2 16.8 35.9 27.2 39.4 28.3 35.9n-C27 1.90 61.2 9.00 22.6 42.3 107 44.2 55.7 2.10 107n-C28 29.3 20.1 12.9 10.8 5.85 5.07 24.1 35.0 23.0 5.07n-C29 4.54 6.85 23.6 39.7 38.2 164 49.4 97.7 289 164n-C30 1.30 196 1.72 7.98 13 24.5 28.7 45.6 17.8 24.5n-C31 530 75.9 109 18.3 157 89.0 16.0 1.55 599 89.0n-C32 181 530 33.9 48.0 64.2 213 124 322 203 213n-C33 130 266 44.7 70.6 52.4 117 98.7 195 99.3 117n-C34 72.6 1514 6.32 bdl 94.9 6.07 2.86 905 2.89 6.07n-C35 6.82 7.69 296 39.6 91.0 0.63 24.0 22.3 80.6 0.63n-C36 491 431 284 440 337 613 484 827 709 613n-C37 bdl bdl bdl 1.16 9.64 18.6 196 14.8 14.0 18.6n-C38 11.0 38.7 bdl bdl 10.3 bdl 4.01 14.9 3.21 bdln-C39 bdl bdl 0.12 bdl bdl bdl bdl 194 bdl bdln-C40 50.6 54.1 42.4 13.4 5.92 bdl 1.98 0.41 41.7 bdln-Alkanes 2725 386 1363 1259 1530 1970 1676 3300 2797 1970Odd/even 0.65 0.25 1.60 0.72 0.99 0.71 0.61 0.34 1.05 0.71TARHC 2.034 0.587 0.599 0.315 1.044 1.518 0.622 1.008 6.29 1.518CPI 0.842 0.35 2.462 1.869 1.91 1.681 0.936 0.518 3.399 1.681Pr/Ph a a a 12.5 10.2 a a a 4.5 a

Pr/n-C17 a 1.296 a a a a 1.201 1.299 a a

Ph/n-C18 0 0 a 0.017 0.032 0 0 0 0.084 0LMW/HMW 0.325 0.406 1.322 1.438 0.953 0.511 0.962 0.407 0.341 0.511Paq 0 0.117 0.054 0.264 0.139 0.202 0 0.495 0.054 0.202

bdl, below detection limit.a Calculations not made due to being divided by zero.

lower than 1 were reported for 510, 3035 and 3540 cm layersshowing a value of 0.35, 0.936 and 0.518, respectively. Theremaining layers showed values above 1 but below 4 which gener-ally suggest oil dominance in the n-alkanes over biogenic sourceslike higher plants plausibly due to contamination from the petrolstation located upstream. The CPI calculated for the 1030 cm

layers suggests involvement of n-alkanes of higher terrestrial plantsand oil. The CPI plot (Fig. 4) showed low values for the upperlayers, while peaking at 1015 cm until the values drop con-sistently till layer 3540 cm after which another peak for thehighest value occurs, before nally dropping again for the 4550 cmlayer.

Fig. 4. Variation of total n-alkanes concentration, odd/even n-alkanes ratio, terrigeneous/aquatic n-alkanes (TARHC), Carbon Preference Index (CPI), low molecular weightand high molecular weight n-alkanes ratio (LMW/HMW), and proportion of aquatic plants (Paq) ratios along the depth prole compared to the deposition time.



Table 3Distribution of predominant n-alkanes through the layers of the core sediment.

Depth (cm) Predominant n-alkane chain

05 n-C15 (15.8%), n-C26 (19.0%), n-C31 (15.6%), n-C36 (12.5%)510 n-C15 (9.9%), n-C32 (12%), n-C34 (32.3%), n-C36 (8.7%)1015 n-C13 (11.1%), n-C15 (26.2%), n-C35 (14.2%), n-C36 (13.3%).1520 n-C15 (29.8%), n-C18 (9.0%), n-C36 (21.8%)2025 n-C13 (8.5%), n-C15 (22.0%), n-C18 (7.3%), n-C31 (7.5%),

n-C36 (14.0%)2530 n-C15 (18.8%), n-C29 (7.1%), n-C32 (8.4%), n-C36 (21.6%)3035 n-C15 (13.4%), n-C16 (9.4%), n-C18 (8.0%), n-C36 (19.5%)3540 n-C15 (7.6%), n-C32 (8.8%), n-C34 (23.3%), n-C36 (20.2%)4045 n-C15 (8.9%), n-C29 (9.3%), n-C31 (18.0%), n-C36 (18.5%)4550 n-C15 (18.8%), n-C29 (7.1%), n-C32 (8.4%), n-C36 (21.6%)

The ratio of hydrocarbons for terrigenous and aquatic sources(TARHC = n-C27 + n-C29 + n-C31/n-C15 + n-C17 + n-C19) is associatedwith the ratio of long-chain hydrocarbons and short-chain hydro-carbons (Bourbonniere and Meyers, 1996; Tenzer et al., 1999). HighTARHC values suggest increased external supply or drainage basin,organic matter source soil and vegetation ground, compared tothe internal source of organic matter, pertaining to the aquaticora (Meyers, 1997; Tenzer et al., 1999). The external source oforganic matter from terrestrial plants is reected in the higherconcentration of n-alkanes with respect to the internal supply ofwater sources, which may result in an unbalanced weight of TARHC(Bourbonniere and Meyers, 1996; Meyers, 1997; Peters et al., 2005).

TARCHC ranged from 0.35 to 3.39, indicating a dominance ofterrigenous organic matter through the layers with only layersbetween 5 and 20 cm and 3035 cm presented an aquatic inu-ence on the organic matter. It was observed that the upper layersnamely, between 5 and 20 cm, display higher aquatic inuence thanthe lower layers pertaining to 20 and 50 cm (except 3035 cm); ter-rigenous material has a tendency to resist further degradation, incontrast to material of aquatic origin owing to the longer carbonchains leading to more apolarity and consequently greater per-sistence. The non-homogeneity between the origin of the organicmatter could be related to variations in rainfall as the maininuence on the distribution dynamics, whereas the terrigenousmaterial may be transported to the reservoir as a runoff resultingfrom the rainfall. Thus, the higher TARHC values in this study arerelated to the high values of n-C31, indicative of the presence ofgrasses, which suggests periods of grass pruning and subsequentlyentering into the water body and further sediment deposition.

Ratio of low molecular weight and high molecular weightof n-alkanes (LMW/HMW), analogous to the CPI index, indi-cates sources of n-alkanes and possible contamination withoil, LMW/HMW = n-Ci/n-Cj (i = 13,14,. . .,20; j = 21,22,. . .,33)(Volkman et al., 1980; Colombo et al., 1989). The indices showedvalues much below 1 for upper (010 cm) and bottom layers(3550 cm), indicating aquatic fauna, higher plants and non pho-tosynthetic bacterial sources (Gearing et al., 1976; Colombo et al.,1989; Commendatore et al., 2000). LMW/HMW values close to onewere found for 2025 and 3035 cm layers, which indicate possiblealgae, plankton, and crude oil sources. Layers between 10 and 20 cmreported values 1.3 and 1.4 respectively, which suggests recentcontamination by oil and degraded oil as a source of n-alkanes.

Ficken et al. (2000) correlated n-alkanes having average (n-C23and n-C25) and long carbon chains (n-C29 and n-C31) with ori-gin and proportion of submerged/oating aquatic plants versusemergent and terrestrial plant sources in lake sediments, themeasure of which is given by the proportion of aquatic plants(Paq = n-C23 + n-C25/n-C23 + n-C25 + n-C29 + n-C31). The core prolepresented a mixed pattern. However, a dominance of emergentmacrophytes at 510, 1530, and 4550 cm layers was observed,where Paq values occurred between 0.1 and 0.4. The dominance

of terrestrial plants was found for the layers 05, 1015, and4045 cm, having values lower than 0.1. Only the 3540 cm layerreported a Paq value between 0.4 and 1, indicating dominance ofsubmerged and oating macrophytes.

3.3. Isoprenoids

Pristane (2,6,10,14-tetramethyilpenthadecano) and phytane(2,6,10,14-tetramethylhexadecano) are present in most sources ofpetroleum, usually as a major constituent within a much widerrange of isoprenoid alkanes (NCR, 1985). The pristane/phytane(Pr/Ph) relationship is considered a biomarker indicator of oxic-ity and anoxia and its use is based on the differential reaction ofphytol, the parent compound mainly derived from the side chainof chlorophylls. Under oxic conditions, phytol is decarboxylated topristane while in a reducing environment, phytol tends to form pre-dominantly phytane. Risatti et al. (1984) stated that methanogenicbacteria, present in anoxic conditions, are an important source ofphytane.

In the present study, phytane was detected in layers beneath thezone of bioturbation, but only in the 1520, 2025, and 4045 cmfractions at a concentration of 1.55, 2.87 and 7.61 g kg1, respec-tively (Table 2). The concentrations were less than that of pristaneand its closely eluting alkane, n-C18. In contrast, pristane, averaging28.6 8.2 g kg1 in the core, showed up in all fractions and rangedbetween 19.4 g kg1 (1520 cm) and 46.6 g kg1 (05 cm), thelast fraction being the bioturbation zone and being more oxidic.This dominance of pristane over phytane could indicate the pri-ority of the conversion of phytol into pristane, a characteristic atoxidic conditions. Measurement of Pr/Ph ratio was possible only inthe layers where phytane was present which were 12.5 (1520 cm),10.2 (2025 cm) and 4.5 (4045 cm). In uncontaminated sedimentsthis ratio usually lies between 3 and 5 (Steinhauer and Boehm,1992). The absence of phytane may be explained by several periodsof bioturbation and tidal as the sample was collected close to theshoreline of the reservoir, which is subjected to seasonal tidal andperiods of oxidic conditions.

The ratios Pr/n-C17 and Ph/n-C18 were applied to the study ofcontaminated areas. Due to the microbial preference, both the iso-prenoids are degraded more slowly than their associated n-alkane,thus high ratios of >2 indicating contribution of recent oil, whilstlower values pertaining to previously degraded residues (Colomboet al., 1989). Although the area has not been subjected to oil spills,the reservoir is in direct line of inuence of a gas station situatedalong the road, about 900 m from the sampling point such that itmay have been subjected to contamination by leakages renderingthe ratios useful. The ratio Ph/n-C18 reported no signicant values,as a result of low or absent levels of phytane while it was pos-sible to calculate Pr/n-C17 ratios of only fractions 510, 3035 and3540 cm. They showed values higher than 1 but lower than 2, pos-sibly due to prior degraded waste while higher ratios could indicatecontamination.

4. Conclusions

The studied area showed signicant inuence from the highway,with sediment deposit originating from the pavement, and suggest-ing sources of pyrolytic origin from the heavy trafc of vehicles fromthe BR 376 highway and a gas station closer to the sample point. Ananalysis of n-alkanes indicated that the region receives signicantcontribution from higher plants, with low contribution originat-ing from autochthonous organic matter. Identied PAHs suggestedpredominance of pyrogenic sources, formed during the pyrolysis offossil fuels, a direct inuence from the heavy highway trafc close-by. Detected DBahA, contributed by particulate pavement, occurs



in signicant concentrations only below 15 cm depth. Sedimentsappear to be toxic and the absence of phytane can be due to sev-eral periods of bioturbation and tidal, the sample being collectedclose to the shoreline. In general, on being compared with othersediments cores, the area seems to be less polluted.

Acknowledgments

We thank Luis Carlos Barbosa for helping us in the eld work andDr. Cristovo Fernandes for the sediment rate data. Sandro Froehnerthanks the National Council of Technological and Scientic Devel-opment (CNPq) grants 300448/2009-0 and 471183/2010-5. JuanSnez thanks the Support Program for the Restructuring and Expan-sion of Federal Universities (UFPR/Reuni) for the post doctoratefellowship grant. The authors would like to thank the anony-mous reviewers for their comments that helped improve themanuscript.

References

Banger, K., Toor, G., Chirenje, T., Ma, L., 2010. Polycyclic aromatic hydrocarbonsin urban soils of different land uses in Miami, Florida. Soil Sed. Contam. 19,231243.

Bcego, M.C., Taniguchi, S., Yogui, G.T., Montone, R.C., da Silva, D.M.A., Lourenc o, R.A.,Martins, C.C., Sasaki, S.T., Pellizari, V.H., Weber, R., 2006. Assessment of contam-ination by polychlorinated biphenyls and aliphatic and aromatic hydrocarbonsin sediments of the Santos and So Vicente Estuary System, So Paulo, Brazil.Mar. Pollut. Bull. 52, 17841832.

Bourbonniere, R.A., Meyers, P.A., 1996. Sedimentary geolipid records of historicalchanges in the watersheds and productivities of Lakes Ontario and Erie. Limnol.Oceanogr. 41 (2), 352359.

Bray, E.E., Evans, E.D., 1961. Distributions of n-parafns as a clue to recognition ofsource beds. Geochim. Cosmochim. Acta 22, 215.

Budzinski, H., Bellocq, I.J.J., Pierard, C., Garrigues, P., 1997. Evaluation of sedimentcontamination by polycyclic aromatic hydrocarbons in the Gironde estuary. Mar.Chem. 58, 8597.

Bzdusek, P.A., Christensen, E.R., Li, A., Qimeng, Z., 2004. Source apportionment ofsediment PAHs in Lake Calumet, Chicago: application of factor analysis withnonnegative constraints. Environ. Sci. Technol. 38, 97103.

Chen, B., Xuan, X., Zhu, L., Wang, J., Gao, Y., Yang, K., 2004. Distribution of polycyclicaromatic hydrocarbons in surface waters, sediments and soils of Hangzhou City,China. Water Res. 38, 35583567.

Colombo, J.C., Pelletier, E., Brochu, C., Khalil, M., 1989. Determination of hydro-carbon sources using n-alkane and polyaromatic hydrocarbon distributionindexes. Case study: Rio de La Plata Estuary, Argentina. Environ. Sci. Technol. 23,888894.

Commendatore, M.G., Esteves, J.L., Colombo, J.C., 2000. Hydrocarbons in coastal sed-iments of Patagonia, Argentina: levels and probable sources. Mar. Pollut. Bull.40 (11), 989998.

Cranwell, P.A., 1984. Lipid geochemistry of sediments from Upton Broad, a smallproductive lake. Org. Geochem. 7, 2537.

Cranwell, P.A., 1973. Chain-length distribution of n-alkanes from lake sedi-ments in relation to post-glacial environmental change. Freshwater Biol. 3,259265.

Cranwell, P.A., Eglinton, G., Robinson, N., 1987. Lipids of aquatic organisms as poten-tial contributors to lacustrine sedimentsII. Org. Geochem. 11, 513527.

de Souza, D.B., 2011. Geochemical composition evaluation of Lacustrine sedimentsorganic matter. Federal Technological University of Parana UTFPR, Graduationdissertation in Technological Chemistry.

de Souza, D.B., Machado, K.S., Froehner, S., Scapulatempo, C.F., Bleninger, T., 2011.Distribution of n-alkanes in lacustrine sediments from subtropical lake in Brazil.Chem. Erde-Geochem. 71 (2), 171176.

Doskey, P.V., Andren, A.W., 1991. Aliphatic Hydrocarbons in Sediment Cores fromthe Southern Basin of Lake Michigan. Argonne National Lab, IL, United States,http://dx.doi.org/10.2172/10141721.

Eglinton, G., Hamilton, R.J., 1963. The distribution of alkanes. In: Swaine, T. (Ed.),Chemical Plant Taxonomy. Academic Press, London/New York, pp. 87217.

Eglinton, G., Hamilton, R.J., 1967. Leaf epicuticular waxes. Science 156,13221335.

Ekpo, B.O., Oyo-Ita, O.E., Wehner, H., 2005. Even-n-alkane/alkene predominancesin surface sediments from the Calabar River, SE Niger Delta, Nigeria. Naturwis-senschaften 92, 341346.

Elias, V.O., Simoneit, B.R.T., Cardoso, J.N., 1997. Even n-alkane predominances on theAmazon Shelf and Northeast Pacic hydrothermal system. Naturwissenschaften84, 415420.

Ficken, K.J., Li, B., Swain, D.L., Eglinton, G., 2000. An n-alkane proxy for the sed-imentary input of submerged/oating freshwater aquatic macrophytes. Org.Geochem. 31, 745749.

Froehner, S., de Souza, D.B., Machado, K.S., Falco, F., Fernandes, C.S., Bleninger,T., Neto, D.M., 2012. Impact of coal tar pavement on polycyclic hydrocarbon

distribution in lacustrine sediments from non-traditional sources. Int. J. Environ.Sci. Technol. 9, 327332.

Froehner, S., Maceno, M., Machado, K.S., 2011. Predicting bioaccumulation of PAHsin the trophic chain in the estuary region of Paranagua, Brazil. Environ. Monit.Assess. 174, 135145.

Froehner, S., Zeni, J., Cardosso da Luz, E., Maceno, M., 2009. Characterization of gran-uloemtric and chemical composition of sediments of Barigui river samples andtheir capacity to retain polycyclic aromatic hydrocarbons. Water Air Soil Pollut.203, 381389.

Gearing, P., Gearing, J.N., Lytle, T.F., Lytle, J.S., 1976. Hydrocarbons in 60 northeastGulf of Mexico shelf sediments: a preliminary survey. Geochim. Cosmochim.Acta 40 (9), 10051017.

Gogou, A., Bouloubassi, I., Stephanou, E.G., 2000. Marine organic geochemistry of theEastern Mediterranean: 1. Aliphatic and polyaromatic hydrocarbons in CretanSea surcial sediments. Mar. Chem. 68, 265282.

Gschwend, P.M., Hites, R.A., 1981. Fluxes of polycyclic aromatic hydrocarbons tomarine and lacustrine sediments in the northeastern United States. Geochim.Cosmochim. Acta 45, 23592367.

Kantek, R.T., Sauter, K.D., Michaliszyn, M.S., 2009. Environmental impacts in theEnvironmental Protection Area (APA) of Guaratuba, State of Paran, Brazil: thetraditional communities point-of-view. Soc. Nat. 21 (2), 3956.

Killops, S., Killops, V., 2005. Introduction to Organic Geochemistry, 2nd ed. BlackwellPublishing, Oxford, ix+393 pp.

Lee, C.L., Hsieh, M.T., Fang, M.D., 2005. Aliphatic and polycyclic aromatic hydrocar-bons in sediments of Kaohsiung Harbour and adjacent coast, Taiwan. Environ.Monit. Assess. 100, 217234.

Lichtfouse, ., Budzinski, H., Garrigues, P., Eglinton, T.I., 1997. Ancient polycyclicaromatic hydrocarbons in modern soils: 13C, 14C and biomarker evidence. Org.Geochem. 26 (56), 353359.

Liu, Y., Chen, L., Jianfu, Z., Qinghui, H., Zhiliang, Z., Hogwen, G., 2008. Distributionand sources of polycyclic aromatic hydrocarbons in surface sediments of riversand an estuary in Shanghai, China. Environ. Pollut. 154, 298305.

Medeiros, P.M., Bcego, M.C., 2004. Investigation of natural and anthropogenichydrocarbon inputs in sediments using geochemical markers. I. So Sebastio,SP, Brazil. Mar. Pollut. Bull. 49, 761769.

Meyers, P.A., 1997. Organic geochemical proxies of paleoceanographic,paleolimnologic, and paleoclimatic processes. Org. Geochem. 27 (56),213250.

Meyers, P.A., 2003. Applications of organic geochemistry to paleolimnologicalreconstructions: a summary of examples from the Laurentian Great Lakes. Org.Geochem. 34, 261289.

National Research Council (NCR), 1985. Oil in the Sea Inputs, Fates, and Effects. Steer-ing Committee for the Petroleum in the Marine Environment Update. NationalResearch Council, Washington DC, 601 p.

Opuene, K., Agbozu, I.E., Ekeh, L.E., 2007. Identication of perylene in sedi-ments: occurrence and diagenetic evolution. Int. J. Environ. Sci. Technol. 4,457462.

Peters, K.E., Walters, C.C., Moldowan, J.M., 2005. The Biomarker Guide. Biomark-ers and Isotopes in Petroleum Exploration and Earth History, vol. 2. CambridgeUniversity Press, Cambridge, UK, pp. 700.

Rieley, G., Collier, R.J., Jones, D.M., Eglinton, G., 1991. The biogeochemistry ofEllesmere Lake, UK. I: source correlation of leaf wax inputs to the sedimentarylipid record. Org. Geochem. 17, 901912.

Risatti, J.B., Rowland, S.J., Yon, D., Maxwell, J.R., 1984. Stereochemical studies ofacyclic isoprenoids, XII. Lipids of methanogenic bacteria and possible contrib-utions to sediments. In: Schenck, P.A., de Leeuw, J.W. (Eds.), Advances in OrganicGeochemistry 1983. Pergamon, Oxford, pp. 93103.

Savinov, V.M., Savinova, T.N., Matishov, G.G., Dahle, S., Naes, K., 2003. Polycyclicaromatic hydrocarbons (PAHs) and organo-chlorines (OCs) in bottom sedi-ments of the Guba Pechenga, Barents Sea, Russia. Sci. Total Environ. 306,3956.

Silveira, C.T., 2005. Landscape ecodynamic units study of Guaratuba/PR APA:subsidies for environmental planning. Federal University of Parana, Curitiba(Dissertation, MSc in Geology).

Simoneit, B.R.T., 1993. Aqueous high-temperature and high-pressure organic geo-chemistry of hydrothermal vent systems. Geochim. Cosmochim. Acta 57 (14),32313243.

Soclo, H.H., Garrigues, P.H., Ewald, M., 2000. Origin of polycyclic aromatic hydrocar-bons (PAHs) in coastal marine sediments: case studies in Cotonou (Benin) andAquitaine (France) areas. Mar. Pollut. Bull. 40, 387396.

Steinhauer, M.S., Boehm, P.D., 1992. The composition and distribution of satu-rated and aromatic hydrocarbons in near shore sediments, river sediments, andcoastal peat of Alaskan Beaufort Sea: implications for detecting anthropogenichydrocarbon inputs. Mar. Environ. Res. 33, 223253.

Tenzer, G.E., Meyers, P.A., Robbins, J.A., Eadie, B.J., Morehead, N.R., Lansing, M.B.,1999. Sedimentary organic matter record of recent environmental changes inthe St. Marys River ecosystem, MichiganOntario border. Org. Geochem. 30(23), 133146.

Venturini, N., Muniz, P., Bcego, M.C., Martins, C.C., Tommasi, L.R., 2008. Petroleumcontamination impact on macrobenthic communities under the inuence of anoil renery: integrating chemical and biological multivariate data. Estuar. Coast.Shelf Sci. 78 (3), 457467.

Volkman, J.K., Eglinton, G., Corner, E.D.S., Sargent, J.R., 1980. Novel unsatu-rated straight-chain C37C39 methyl and ethyl ketones in marine sed-iments and a coccolithophore Emilianiahuxleyi. Phys. Chem. Earth 12,219227.



Wan, G.J., Chen, J.A., Wu, F.C., Xu, S.Q., Bai, Z.G., Wan, E.Y., Wang, C.S., Huang, R.G.,Yeager, K.M., Santschi, P.H., 2005. Coupling between 210Pb and organic matter insediments of a nutrient-enriched lake: an example from Lake Chenghai, China.Chem. Geol. 224, 223226.

Yunker, M.B., Backus, S.M., Graf Pannatier, E., Jeffries, D.S., Macdonald, R.W., 2002b.Sources and signicance of alkane and PAH hydrocarbons in Canadian ArcticRivers. Estuar. Coast. Shelf Sci. 55, 131.

Yunker, M.B., MacDonald, R.W., Goyette, D., Paton, D.W., Fowler, B.R., Sullivan, D.,Boyd, J., 1999. Natural and anthropogenic inputs of hydrocarbons to the Straitof Georgia. Sci. Total Environ. 225, 181209.

Yunker, M.B., Macdonald, R.W., Vingarzan, R., Mitchell, R.H., Goyette, D., Sylvestre,S., 2002a. PAHs in the Fraser river basin: a critical appraisal of PAH ratios asindicators of PAH source and composition. Org. Geochem. 33, 489515.

Use of Biomarkers Indices in a Sediment Core to Evaluate Potential Pollution Sources in a...

Documents

Transcript of Use of Biomarkers Indices in a Sediment Core to Evaluate Potential Pollution Sources in a...