Chemosphere 58 (2005) 905–915

www.elsevier.com/locate/chemosphere

Persistent toxic substances in soils and waters alongan altitudinal gradient in the Laja River Basin,

Central Southern Chile

Ricardo Barra a,*, Peter Popp b, Roberto Quiroz a, Coretta Bauer b,Hernan Cid a, Wolf von Tumpling b

a Aquatic Systems Research Unit, EULA-Chile Environmental Sciences Center, University of Concepcion,

Barrio Universitario S/N, P.O. Box 160-C, Concepcion, Chileb UFZ Center for Environmental Research, Departments of Analytical Chemistry and Inland Waters Research,

Leipzig-Halle, Magdeburg, Germany

Received 24 March 2004; received in revised form 27 August 2004; accepted 24 September 2004

Abstract

In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, super-

ficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objec-

tive was to establish the basin�s contamination status. The working hypothesis was that PTS levels and distribution in

the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three

organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and

from a coastal reference station (Lleu–Lleu River). Soil samples were extracted using accelerated solvent extraction with

acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and

snow samples by liquid–liquid extraction (LLE). PAH and organochlorine compound quantification was carried out

by HPLC with fluorescence detection and GC–MS, respectively. PCBs in soils presented four different profiles in the

altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated

pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data

from other remote areas of the world. HigherP

PAHs levels in soils were found in the station located at 227masl

(4243ngg�1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher

than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions.

No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling sta-

tions with the highest levels being found in Laja Lake waters, where 1.1ng/l were observed. This concentration is two

times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine com-

pound in snow sampled at the highest elevation point of the basin is indicative of the transport and atmospheric dep-

osition phenomena of a-HCH, c-HCH and PCB 52, with values being similar to the levels reported in Canadian snow

samples. We conclude that environmental PTS substance levels are in general relatively low, although PAHs may be of

concern in some areas of the basin.

� 2004 Elsevier Ltd. All rights reserved.

0045-6535/$ - see front matter � 2004 Elsevier Ltd. All rights reserved.

doi:10.1016/j.chemosphere.2004.09.050

* Corresponding author. Tel.: +56 41 204 013; fax: +56 41 207 076.

E-mail address: ricbarra@udec.cl (R. Barra).

906 R. Barra et al. / Chemosphere 58 (2005) 905–915

Keywords: Laja River; Chile; POPs; Soils; Waters; Snow; Pollution; PAHs

1. Introduction

Persistent toxic substances (PTS) belong to a chemi-

cal class that is bioaccumulative, resistant to degrada-

tion, and possesses toxic properties. At present, there

is concern due to these pollutants� ability to travel long

distances through the atmosphere or oceans to places

where these compounds have never been used before

(UNEP, 2003).

A PTS study in different environmental compart-

ments such as soils, sediments, water and snow in geo-

graphical areas with a continuous matter cycling flux

could provide insights on the biogeochemical cycling

of the pollutants within hydrographical basins according

to their anthropogenic influence (Grimalt et al., 2001).

Recently, research has focused on altitudinal gradi-

ents (Blais et al., 1998) where similar pollution patterns

previously observed at latitudinal gradients are being

observed in mountains areas, i.e. highland areas seems

to be receiving a higher pollutant burden from nearby

source areas. This fact needs to be studied in detail in

the Southern Hemisphere where pollution levels seem

to be lower than in the northern industrialized

hemisphere.

PTS behavior and dynamics in the Southern Hemi-

sphere, and particularly in Chile, is poorly understood

(Barra et al., 2001; Munoz et al., 2003). There exist some

antecedents in biotic matrices, such as fish from different

trophic levels (Fuentealba, 1997), invertebrates (Palma

et al., 1998), bird eggs (Munoz and Becker, 1999;

Munoz et al., 2003), water birds and freshwater fish

(Focardi et al., 1996), and in abiotic matrices such as

sediments (Barra et al., 2001, 2004).

Soils are very important in the fate and distribution

of PTS in the environment since they have a huge reten-

tion capacity and they may work as re-emission sources

for the atmosphere (Wild and Jones, 1995; Harner et al.,

2001). The net PTS content in soils reflects both the in-

puts and losses, assuming that atmospheric deposition is

the main entry pathway in remote areas (Meijer et al.,

2002). Pollutant entry into the soil is highly dependent

on soil uses and environmental variables as well as the

physicochemical properties of the pollutant. The princi-

pal loss pathways are volatilization, degradation and

leaching, which are greatly affected by temperatures

(Hippelein and McLachlan, 2000; Sinkkonen and Paasi-

virta, 2000).

Water has a limited capacity for holding PTS due to

their low water solubility and high partitioning coeffi-

cient towards sediment and organic matter. However,

river waters can be efficient transport pathways within

hydrographic basins towards the ocean (UNEP, 2003).

On the other hand, snow water can act as an efficient

scavenger of vapor and particulate atmospheric pollut-

ants (Franz and Eisenreich, 1998). The presence of

detectable pollution in snow samples from remote areas

could be used as evidence for atmospheric deposition in

highland areas.

This paper reports the results for a selected set of PTS

levels obtained during a 2002 survey in the Laja River

Basin in Central South Chile. The targeted compounds

were pesticides (DDTs, HCHs) industrial compounds

(PCBs, HCB), and polyaromatic hydrocarbons (PAHs).

We established three sampling sites along the river basin

as well as one coastal reference site for soil and water

analysis. In addition, water samples from the Laja Lake

in the Andes Mountains and snow samples from a per-

manent snowfield located at the highest elevation point

within the basin, above 2300m altitude, were analyzed.

The working hypothesis was that PTS environmental

levels are directly related to the influence of anthropo-

genic activities at each sampling site.

2. Material and methods

2.1. Study area

The Laja River Basin covers a total area of 4600km2,

is located in the Andes Mountains east of the Antuco

Volcano in South Central Chile (VIII Region, between

36�54 0, 37�39 0 SL and 71�05 0 and 72�43 0 WL). Its alti-

tude varies from 3585masl in the Sierra Velluda Moun-

tains to 40masl at the river mouth where it joins the

Biobio River (Fig. 1).

The climate is characterized as a warm, template cli-

mate with a rainy winter season. Precipitation events

come as cyclone-type frontal systems, and are concen-

trated in the period between April and September. In

the Andean area, there is cold highland weather without

dry months, presenting an average annual precipitation

rate above 2500mm and that reaches 4000mm in the

highland areas.

The basin topography can be classified in three main

zones. The high area formed by the Andes Mountains

with an average altitude of 2000masl, where the Antuco

Volcano and Sierra Velluda stand out with altitudes of

2985masl and 3585masl, respectively. The pre-Andean

zone, with altitudes between 400 and 600masl, is charac-

terized by the river�s deep penetration into the glacier-

originated valley, whose width reaches 4km. Low altitude

hills and small slopes characterize the lower basin zone.

On the basin�s west side, the coastal range becomes the

western border with altitudes reaching 500masl.

Fig. 1. Study area location, indicating the type of samples taken in each site.

R. Barra et al. / Chemosphere 58 (2005) 905–915 907

The basin is subjected to multiple uses where the

most important are hydropower energy generation (with

a complex of three dams in the upper part of the basin),

forestry and agriculture. Only small towns with less than

20.000 inhabitants are present in the basin area.

3. The Laja Lake

One of the main elements within the basin is the Laja

Lake, located at 1368masl with a total surface area of

100km2, average depth of 75m, and a total drainage basin

of about 975km2. The Laja Lake is of glacial and volcanic

eruption origin (the last eruption of Laja Volcano was in

the 19th century, and provoked an elevation in 20mof the

water level (Fig. 1)).

The river starts with the Laja Lake ground filtrations

3km west of the lake. The river runoff is from east to

west with a total longitude of 124.8km. It subsequently

receives the waters draining in from small Andean

streams, following a course along sandy banks produc-

ing an important transport during winter and snow

melting periods.

4. Sampling sites

Three sites for soil and water sampling were selected

along the river as well as one coastal reference site, all

located within the VIII Region in South Central Chile.

Additionally, water samples were taken in the Laja Lake

and snow samples were obtained from a permanent

snowfield in the Sierra Velluda Mountain, the highest

elevation point within the basin. The location of the

sampling stations is shown in Fig. 1. All soil and water

sampling sites along the river and in the reference site

have similar landscape characteristics (i.e. forestry plan-

tations along their course).

908 R. Barra et al. / Chemosphere 58 (2005) 905–915

Lleu–Lleu River: This river drains from the lake of

same name, is located on the coast, and receives some

marine waters affected by the tides. The land use is

mainly forestry and agriculture (Fig. 1B, Site 00).

Puente Perales: Located in an agricultural-forestry

area near the towns of Laja (industry) and Yumbel

(agriculture-forestry), the area is the river potamon with

fine textured sediments. The land use is mainly forestry

and agriculture (Fig. 1A Site 01).

Cholguan: Located in a forestry area near an indus-

trial setting (sawmill and wood-panel production). The

land use is mainly forestry (Fig. 1A Site 02).

Campamento Viejo: Located at the beginning of the

Laja National Park near hydroelectric dams and for-

estry activities. The land use is mainly native forest

(Fig. 1A site 03).

Laja Lake: Located with the Laja National Park. The

land use is mainly nude rocks and some native forest

(Fig. 1A site 04).

Sierra Velluda mountains: A permanent snowfield

(Fig. 1A site 05).

5. Sampling procedure

5.1. Soil

In each sampling site, the top 10cm were sampled at

five points: the four corners of a square matrix of

100 · 100m, and the central point. To analyze the varia-

bility within the sampling soils a pre-investigation was

conducted in two sampling sites (Lleulleu and Chol-

guan), where soil samples were analyzed separately and

in an integrated sample. Since the comparison between

all five samples and the integrated one presented a differ-

ence lower than 20%, analysis of the integrated sample

was selected. Samples were stored in aluminum foil and

then stored in plastic hermetic bags for later analysis.

5.2. Water and snow

Grab water samples were taken in duplicate at each

sampling site considering only surface waters. Seven

snow samples were taken with a metallic corer, removing

only surface snow from a permanent snowfield in the

Sierra Velluda Mountains. Samples were stored on ice

until transported to the Laboratory, where they were

frozen at �20 �C.

6. Analytical procedures

6.1. PAHs in soils

Soil samples were mixed with anhydrous sodium sul-

fate, and then extracted by accelerated solvent extrac-

tion with acetone:cyclohexane (1:1) at 150 �C, 14MPa

for 5min (three times). Extracts were combined and con-

centrated to 5ml.

PAH analysis was performed in 200ll of the above

extracts, concentrated to dryness and re-suspended in

200ll of acetonitrile. The homogenization was per-

formed by sonication (5min). The analysis was per-

formed with an HPLC HP1050 with a programmable

fluorescence detector using a chromatographic column

LiChroCART 250-3, Lichrospher PAH (5lm) at

20 �C. The mobile phase was acetonitrile:water (50%

V:V), increasing the acetonitrile proportion to 60% (0–

3min) and 100% (3–14min), which was maintained con-

stant until 24min. The PAH detection limits in soils were

between 0.03ng/g (benzo(k)fluoranthene) and 0.15ng/g

(indeno(1,2,3-cd)pyrene) and the detection limits of the

other compounds were between 0.01ng/g and 0.03ng/g.

6.2. Organochlorines and PCBs in soils

For the organochlorine compounds analysis, 2ml of

the above extracts (see PAHs in soil) were concentrated

to 0.2ml and then cleaned up in a Florisil column

(10mm i.d., 3g Florisil).

The conditions of the performed GC/MS analysis

were: column from Machery Nagel (Optima d6, 60m,

0.25mm, 0.25lm film thickness). The temperature pro-

gram was 80 �C, then 3min isothermal, 15 �C/min to

160 �C, then 3 �C/min to 280 �C hold for 12min. Quanti-

fication was performed with the external standard

method with six calibration levels.

6.3. Organochlorines and PCBs in water and snow

Snow and water samples (500ml) were analyzed with

liquid–liquid extraction followed by GC–MS for HCHs,

HCB and DDT and metabolites. The extracts were con-

centrated to 1ml and analyzed by GC/MS as described

above. Detection limits for PCBs, HCB, HCHs, p,p 0-

DDE and p,p 0-DDT in water and snow were between

0.05ng/l (HCB) and 0.63ng/l (b-HCH).

6.4. Standards and reference materials

The HCH standard materials were obtained from

Riedel de Haen, HCB, the DDX reference materials

were obtained from Dr. Ehrenstorfer, and the PCB ref-

erence material. The PCB selection criterion used was

the German standard method for the determination of

water, waste and sludge-jointly determinable substances

(group F)—part 3: determination of polychlorinated

biphenyls (DIN 38407-3). PCB reference material was

purchased from Promochem. The PAH calibration mix

(10mg of each compound per ml acetonitrile) was sup-

plied by Supelco. HPLC grade water and acetonitrile

were supplied by Baker.

Table 1

Characterization of sampling stations

Stations Basin Altitude (masl) Ubication Temperaturea (�C) Samples Land use

00 Lleu–Lleu River 6 38�07028.800S 12.5 Soil, water Forestry, Agriculture

73�26007.200W

01 Laja River 63 37�14023.200S 12.2 Soil, water Forestry, Agriculture

72�30052.800W

02 Laja River 227 37�11009.200S 11.2 Soil, water Forestry

72�04001.200W

03 Laja River 864 37�22055.400S 7.3 Soil, water Native forest

71�28006.800W

04 Laja Lake 1386 37�22028.500S 4.1 Water Native forest, Rocks

71�22002.900W

05 Laja Mountain 2648 37�26057.000S n.i. Snow Permanent snowfield

71�24007.300W

n.i.: no information.a Annual mean.

R. Barra et al. / Chemosphere 58 (2005) 905–915 909

6.5. Organic carbon determination

Total organic carbon (TOC) was determined accord-

ing to the method of Gaudette et al. (1974). Ten millili-

tres of 1N K2Cr2O7 solution was added to 0.5g of dry

soil; then 20ml of concentrated sulfuric acid was added

and the mixture was gently shaken, and left to digest for

30min. The solution was then diluted to 200ml with dis-

tilled water, and 10ml of phosphoric acid and 0.2g of

NaF was added. Finally, the solution was cooled and ti-

trated with anhydrous ferrous sulfate ammonium.

6.6. Statistical analysis

Statistical analysis was performed using TOC norma-

lized data. Pearson correlations were calculated between

compounds through a statistical software package

(STATISTICA (Statsoft Inc., 1997)). Factorial analysis

was carried out to determine correlation between varia-

bles. Principal component analysis was performed using

normalized data. New variables in these analyses repre-

sented by axes are derived from linear combinations of

the original variables. The first axis explains the maxi-

mum amount of variation within the data set. Subse-

quent axes are derived with the added constraint that

they are orthogonal to the previously derived axes.

Spatial arrangement of PAHs was analyzed to under-

stand relationships among the different components

detected.

7. Results and discussion

7.1. Soils

Soil samples were analyzed for OCPs, PCBs and

PAHs in the integrated samples. Each sampling point

was located near the river. All soil samples were analyzed

for organic carbon content for comparative purposes.

Each sampling point was characterized according to

the main land use patterns. Table 1 shows the distribu-

tion of land uses in each sampling site.

7.2. Soil organochlorines

The chlorinated compounds c-HCH, p,p 0-DDE, HCB

and all PCBs analyzed are detected in all the stations. a-HCH is well above detection levels in the coastal sam-

pling site (more than two orders of magnitude higher).

PCBs levels ranged between 8.9 and 16.8ng/g OC

and the p,p 0-DDE level was between 2.02 and 4.79ng/g

OC.

No altitudinal gradients could be described for the

different analyzed compounds, where four groups of

compounds could be identified according to the environ-

mental levels and fingerprints found in the different

sampling sites. PCB 52, PCB 101 and HCB are homoge-

neously distributed along the gradient; however PCB

153, PCB 138, PCB 180 and c-HCH are clearly high in

the Cholguan sampling site (02), and finally p,p 0-DDE

showed higher levels in the sites 01 and 02 (Fig. 2a–c).

Levels were homogeneously distributed among the dif-

ferent stations despite their anthropogenic influence.

For instance, p,p 0-DDE was higher in samples where

forestry and agricultural activities predominate and less

natural areas are involved. These stations were histori-

cally used for agricultural purposes (Puente Perales

and Cholguan). No p,p 0-DDT was detected in any of

the analyzed samples, indicating the absence of fresh

DDT discharges in the study area. p,p 0-DDE concentra-

tions in both Puente Perales (01) and Cholguan (02) are

two times the observed reference site concentrations

(Fig. 2c). Again, the Cholguan site (02) presented the

highest concentrations of PCB 153, PCB 180, PCB 138

Fig. 2. Organochlorines in soils samples along the altitudinal gradient, classified according observed patterns (a–c), and the altitudinal

concentration gradient observed for PCB 28 (d).

910 R. Barra et al. / Chemosphere 58 (2005) 905–915

and c-HCH (Fig. 2b). In this site, a clear industrial influ-

ence (a saw mill and a wood-panel industry are near the

sampling site) is noted. Concentrations of these pollut-

ants are two times higher than the other sampling sites.

The above mentioned PCBs represent some of the most

common and persistent PCBs in historically used com-

mercial PCB mixtures such as Aroclor 1260 and Aroclor

1254 (Schultz et al., 1989; Newman et al., 1998). How-

ever, for PCB 101, 52 and HCB, no differences are ob-

served and they are homogeneously distributed among

the different sampling stations (Fig. 2a). A possible

explanation for such observed results could be that

Henry�s Law constants of PCBs with lower molecular

weights produces volatilization losses that are higher

than heavier congeners, and therefore, there is a high

potential of mixing with the surrounding atmosphere,

resulting in quite homogeneous levels in all sampling

sites. An exception to this fact could be the PCB 28,

which was the only compound where a clear altitudinal

gradient was observed i.e. the highest concentrations

were detected in the higher elevation samples (Fig. 2d).

It is probable that this altitudinal gradient could be par-

tially explained by the relatively high Koa observed for

PCB 28 with respect to the other analyzed PCB conge-

ners. More insights regarding this effect are not possible

due to the limited number of PCBs congeners analyzed

in this work.

Octanol air partitioning coefficients are indicative of

the ability of the POPs to be transferred from organic

matrices (soils, leaves) to air under equilibrium condi-

R. Barra et al. / Chemosphere 58 (2005) 905–915 911

tions. Koa relationships and concentration observed in

our study agree with higher values for the more substi-

tuted PCB congeners. It is likely that the higher content

of organic carbon in soils also contributes to a high PCB

burden, suggesting that PCB burden in soils is related to

the organic carbon content. PCB 28 has lower Log Koa,

and therefore a high tendency to move towards the

atmospheric environment, reflecting a clear altitudinal

gradient (Fig. 2d). However, the other PCBs did not pre-

sent any altitudinal trend.

The a/c-HCH ratio is often used for distinguish the

use of technical (>1) or pure formulations (<1) of lin-

dane (Ballschmiter and Wittlinger, 1991; Haugen et al.,

1998). At the Cholguan station, that ratio was 2, indicat-

ing the technical formulation use, which contrasts with

other information gathered in Chile where a dominance

of pure lindane is clear (Barra et al., 2001; Barra et al.,

2004). It might be possible then, that the sources of both

compounds are different; i.e. lindane derives from their

recent use as insecticide, but a-HCH may come from

atmospheric deposition.

In general for organochlorine compounds, it can be

established that lindane levels reflect a pattern of rela-

tively recent use throughout the basin since these com-

pounds were only recently forbidden for agricultural

purposes in 1998 (Barra et al., 2004) and there is a clear

relationship with agricultural surrounding areas to the

sampling sites. p,p 0-DDE levels seem to indicate that

fresh DDT is no longer being used within the basin; in

fact, DDT was forbidden more than 10years ago, but

the persistent DDE levels still continue to be detected

in the analyzed samples.

Fig. 3. PAHs profile in soil samples in

The analyzed PCB levels indicate that PCB pollution

is widely distributed along the basin gradient, where the

heavier (molecular weight), persistent, and abundant

congeners in commercial PCB mixtures (153,138,180)

present consistently higher values than the levels ob-

served in the reference site at the coast, indicating the

influence of sources located probably within the basin.

The rest of the PCB congeners and the volatile HCBs

are reflecting a more widely distributed contamination

in the region, since no differences could be established

with the reference zone.

7.3. Soil PAHs

PAHs levels are well above detection limits, where

the values were eight times higher in the Cholguan sta-

tion (site 02) than in the other sampling sites with aPPAHs of 4243ng/g OC. Values were in the order of

600ng/g OC. PAHs fingerprints were similar between

the Campamento Viejo and Puente Perales sites (Fig. 3).

Higher levels in the Cholguan station (site 02) is

clearly related to anthropogenic influence, and could be

due to the PAH incorporation in soils due to forest fires

and the presence of wood pallets using boilers feed with

wood residues. In general terms, PAH levels reported in

this paper, are lower there than in areas with a high level

of human influence, but higher than zones receiving only

natural inputs. According to the classification proposed

by Maliszewska-Kordybach (1996), a soil PAH concen-

tration between 200ngg�1 and 600ngg�1 d.w. is conside-

red as weakly contaminated, a soil PAH concentration

between 600 and 1000ngg�1 d.w. is a contaminated soil,

the different sampling stations.

Fig. 4. Principal component analysis of PAHs in soils.

912 R. Barra et al. / Chemosphere 58 (2005) 905–915

and concentrations above 1000ngg�1 d.w. is a heavily

contaminated soil. Therefore, it can be stated that levels

found in two of the three sites in the Laja River Basin re-

flect a medium-low level of pollution due to PAHs, while

the Cholguan site (02) represents a heavily contaminated

soil.

To evaluate the potential soil sources of PAHs, we

compared the fingerprints obtained in this study with

the results observed in the literature for both environ-

mental levels and emission sources. This evaluation is

based on the hypothesis that the main input of PAHs

in these soils is from atmospheric deposition, and obvi-

ously that the profiles found in sources are not different

from the profiles found in the receptor environment

when sampling sites and sources are relatively near. We

compared only eight PAHs from the analyzed soils:

naphthalene, fluorene, phenanthrene, anthracene, fluo-

ranthene, pyrene, benzo(a)anthracene and chrysene. In

the PCA analysis, we included the profiles determined

by Jenkins et al. (1996), Lao et al. (1975) and the PAHs

determined by Wilcke et al. (2002) for human impacted

environments (gas station, highway and a home garden).

Fig. 4 presents the results of the analysis. From the fig-

ure, it follows that the profiles obtained for the Laja

Basin are clearly intermediates between some pyrolitic

profiles and the profiles obtained in polluted environ-

ments. Neither coal combustion nor wood combustion

seems to affect the PAH profile observed in the Cholguan

site (site 02), although the profiles are similar to those ob-

served in human impacted environments. These two fac-

tors explain more than the 90% of the variability

observed. Factor 1 could be interpreted as the sources

of PAHs and the factor 2 as the degradation and selec-

tion processes occurring between the source and the

receptor site in soils. The reference site (site 00) and the

Cholguan site (site 02) range from pyrolitic profiles to

coal combustion dominated profiles found in contami-

nated soils, respectively. The other two sites represent

intermediate profiles. All these results indicate that

PAH distribution and levels in soils reflect local rather

than regional conditions.

7.4. Waters

No pesticides nor PCBs 180 and 153 were detected in

the water samples. PCB 52 was detected in all the sam-

pling sites including the reference site. Total PCBs were

higher in Laja Lake water where the frequency of indi-

viduals PCB detection was high (Table 2). Total PCBs

levels reached 1ng/l in the lake. This result could be de-

rived from: the nearby hydropower stations located in

the upper part of the basin and/or the atmospheric dep-

osition and cold condensation effect. In fact the ob-

served levels are higher than levels detected in other

lakes in the world such as the Lake Baikal and in the

Upper Great Lakes, where reported levels of total dis-

solved PCBs (measured as Aroclor 1260 and 1254)

reached 0.5ng/l (Kucklick et al., 1994). Even though

the concentrations are not very low, the observed

concentrations in the lake water were higher than in

the river waters. Detection limits obtained with the

reported method (Popp et al., 2003) are above the range

of 0.1ng/l, and therefore, transport from the lake into

the river is feasible and probably occurring, although

the levels reached due to dilution effects may prevent the

positive detection by the analytical methods used.

7.5. Snow samples

The samples analyzed for chlorinated compounds

were obtained above 2.300masl in a permanent snow-

field. The most frequently detected compounds were

Table 2

Organochlorine compounds in surface waters, concentrations in ng/l ± Std

Stations

00 01 02 03 04

PCB 28 n.q. n.q. n.q. n.q. 0.23 ± 0.06

PCB 52 0.33 ± 0.12 n.q. 0.19 ± 0.07 0.18 ± 0.09 0.33 ± 0.15

PCB 101 n.q. n.q. n.q. n.q. 0.23 ± 0.06

PCB 153 n.q. n.q. n.q. n.q. n.q.

PCB 138 n.q. n.q. n.q. n.q. 0.23 ± 0.1

PCB 180 n.q. n.q. n.q. n.q. n.q.PPCBs 0.33 – 0.19 0.18 1.01

n.q.—No quantified.

R. Barra et al. / Chemosphere 58 (2005) 905–915 913

the a-HCH isomer and the PCB 52 followed by the

c-HCH and PCB 28 and 101. The other compounds

were below the detection limits (Table 3).

The presence of chlorinated compounds in snow

samples is clearly a demonstration that pesticides and

PCBs are arriving into the Andes system by atmospheric

transport and deposition processes, in particular a-HCH, c-HCH and PCB 52, revealing the high environ-

mental mobility of these compounds. The a/c ratios in

those snow samples where both compounds were de-

tected are close to 1, in agreement with the reported

ratio for other environmental compartments (sediments)

within the region (Barra et al., 2001) and in the Southern

Hemisphere (Ballschmiter and Wittlinger, 1991; Haugen

et al., 1998). In one sample, p,p 0DDT is also detected

above detection limits, probably derived from a recent

Table 3

Levels of organochlorines compounds in snow from seven samples o

Sample A Sample B Sample C S

a-HCH 0.60 ± 0.25 n.q. 0.43 ± 0.09 9

b-HCH n.q. n.q. n.q. n

c-HCH 0.60 ± 0.36 n.q. n.q. n

d-HCH n.q. n.q. n.q. n

e-HCH n.q. n.q. n.q. n

a/c 1.0 – – –

HCB n.q. n.q. n.q. n

o,p 0-DDE n.q. n.q. n.q. n

p,p 0-DDE n.q. n.q. n.q. n

o,p 0-DDD n.q. n.q. n.q. n

p,p 0-DDD n.q. n.q. n.q. n

o,p 0-DDT n.q. n.q. n.q. n

p,p 0-DDT n.q. 1,13 n.q. n

PCB 28 0.18 ± 0.16 0.18 ± 0.04 n.q. n

PCB 52 0.20 ± 0.13 0.32 ± 0.21 n.q. 0

PCB 101 0.17 ± 0.11 0.17 ± 0.13 n.q. n

PCB 153 0.16 ± 0.05 n.q. n.q. n

PCB 138 0.25 ± 0.18 n.q. n.q. n

PCB 180 n.q. n.q. n.q. nPPCBs 0.96 0.68 – 0

Concentrations in ng/l ± Std. n.q.—Levels below the detection limits.

use, transport and deposition of this pesticide. How-

ever, more data is needed to confirm this result. Levels

found in our study are similar to those levels reported

for Canadian snow samples (Gregor and Grummer,

1989).

The observed PTS levels reflect a snapshot of the

environmental levels along an altitudinal gradient in

South Central Chile within a basin with relatively low

anthropogenic impacts, except for hydropower genera-

tion and forestry activities. The level of chlorinated pes-

ticides reflects the historical use of pesticides, but the

levels found are generally low when compared to the lev-

els described for remote soils in Europe and North

America (Fu et al., 2001; Ribes et al., 2002). All these re-

sults point out that except for the anthropogenic influ-

ence, chlorinated pesticide levels are very low.

btained in the Sierra Velluda Mountains (Site 05)

ample D Sample E Sample F Sample G

.21 ± 5.36 3.65 ± 1.3 1.20 ± 0.93 0.44 ± 0.18

.q. n.q. n.q. n.q.

.q. 0.38 ± 0.06 1.39 ± 0.58 0.45 ± 0.24

.q. n.q. 0.82 n.q.

.q. n.q. n.q. n.q.

9.7 0.9 1.0

.q. n.q. 0.14 ± 0.06 n.q.

.q. n.q. n.q. n.q.

.q. n.q. n.q. n.q.

.q. n.q. n.q. n.q.

.q. n.q. n.q. n.q.

.q. n.q. n.q. n.q.

.q. n.q. n.q. n.q.

.q. n.q. 0.26 ± 0.17 n.q.

.14 ± 0.08 0.16 ± 0.07 0.33 ± 0.19 0.16 ± 0.05

.q. n.q. 0.21 ± 0.04 n.q.

.q. n.q. 0.18 ± 0.12 n.q.

.q. n.q. 0.26 ± 0.21 n.q.

.q. n.q. n.q. n.q.

.14 0.16 1.24 0.16

914 R. Barra et al. / Chemosphere 58 (2005) 905–915

In conclusion, PCBs levels in soils samples are also

very low, three to four magnitude orders below concen-

trations detected in heavily polluted zones within the

country, but comparable to remote soils from the

Northern Hemisphere. In general, organochlorine com-

pounds are widely distributed within the area being de-

tected in all the analyzed matrices, with fairly

homogeneous levels for soil, snow and water samples.

PAH levels in soils, however, are more related to local

contaminating sources near the sampling areas and re-

ported data could be of some concern.

Acknowledgments

This research was funded by FONDECYT Grant

1010640 and CONICYT (Chile)/BMBF (Germany)

International Scientific Cooperation Program Project

No. 2000-111 Granted to Dr. Peter Popp (UFZ-Ger-

many) and Dr. Ricardo Barra (EULA-Chile).

References

Ballschmiter, K., Wittlinger, R., 1991. Interhemisphere

exchange of hexachlorocyclohexanes, hexachlorobenzene,

polychlorinated biphenyls, and 1,1,1-trichloro-2,2-bis(p-

chlorophenyl)ethane in lower troposphere. Environ. Sci.

Technol. 25, 1103–1111.

Barra, R., Cisternas, M., Urrutia, R., Pozo, K., Pacheco, P.,

Parra, O., Focardi, S., 2001. First report on Chlorinated

pesticides deposition in a sediment core a small lake in

central Chile. Chemosphere 45, 749–757.

Barra, R., Cisternas, M., Suarez, C., Araneda, A., Pinones, O.,

Popp, P., 2004. PCBs and HCHs in a salt-marsh sediment

record from South-Central Chile: use of tsunami signatures

and 137Cs fallout as temporal markers. Chemosphere 55,

965–972.

Blais, J.M., Schindler, D.W., Muir, D.C.G., Kimpe, L.E.,

Donald, D.B., Rosenberg, B., 1998. Accumulation of

persistent organochlorine compounds in mountains of

western Canada. Nature 395, 585–588.

Focardi, S., Fossi, M., Leonzio, C., Corsolini, S., Parra, O.,

1996. Persistent organochlorine residues in fish and birds

from the Biobio River, Chile. Environ. Monit. Assess. 43,

73–92.

Franz, T., Eisenreich, S., 1998. Snow scavenging of polychlo-

rinated and polycyclic aromatic hydrocarbons in Minne-

sota. Environ. Sci. Technol. 32, 1771–1778.

Fu, S., Chu, S., Xu, X., 2001. Organochlorine pesticide residue

in soils from Tibet, China. Bull. Environ. Contam. Toxicol.

66, 171–177.

Fuentealba, M., 1997. Pesticidas organoclorados y bifenilos

policlorados en Trachurus murphyi en la zona de centro Sur

de Chile. Bol. Soc. Biol. 68, 39–46.

Gaudette, H.E., Flight, W.R., Toner, L., Folger, D.W., 1974.

An inexpensive titration method for determination of

organic carbon in recent sediments. J. Sediment. Petrol.

44, 249–253.

Gregor, D., Grummer, W., 1989. Evidence of atmospheric

transport and deposition of organochlorine pesticides and

polychlorinated biphenyls in Canadian arctic snow. Envi-

ron. Sci. Technol. 23, 562–565.

Grimalt, J., Fernandez, P., Berdie, L., Vilanova, R., Catalan, J.,

Psenner, R., Hofer, R., Appleby, P., Rosseland, B., Lien, L.,

Massabuau, J., Battarbee, R., 2001. Selective trapping of

organochlorine compounds in mountain lakes of temperate

areas. Environ. Sci. Technol. 35 (13), 2690–2697.

Harner, T., Bidleman, T., Jantunen, L., Mackay, D., 2001. Soil-

air exchange model of persistent pesticides in the United

States cotton belt. Environ. Toxicol. Chem. 20, 1612–1621.

Haugen, J., Wania, F., Ritter, N., Schlabach, M., 1998.

Hexachlorohexenes in air in Southern Norway. Temporal

variation, sources allocation, and temperature dependence.

Environ. Sci. Technol. 32, 217–224.

Hippelein, M., McLachlan, M.S., 2000. Soil/air partitioning of

semivolatile organic compounds. 2. Influence of temperature

and relative humidity. Environ. Sci. Technol. 34, 3521–3526.

Jenkins, B., Jones, A., Turn, S., Williams, R., 1996. Emission

factors for polycyclic aromatic hydrocarbons from biomass

burning. Environ. Sci. Technol. 30, 2462–2469.

Kucklick, J., Bidleman, T., McConnell, L., Walla, M., Ivanov,

G., 1994. Organochlorines in water and biota of lake Baikal

Siberia. Environ. Sci. Technol. 28, 31–37.

Lao, R., Thomas, R., Monkman, J.L., 1975. Computerized gas

chromatographic–mass spectrometric analysis of polycyclic

aromatic hydrocarbons in environmental samples. J. Chro-

matogr. 112, 681–700.

Maliszewska-Kordybach, B., 1996. Polycyclic aromatic hydro-

carbons in agricultural soils in Poland: preliminary propo-

sals for criteria to evaluate the level of soil contamination.

Appl. Geochem. 11, 121–127.

Meijer, S., Steinnes, E., Ockenden, W., Jones, K., 2002.

Influence of environmental variables on the spatial distri-

bution of PCBs in Norwegian and UK soils: Implications

for global cycling. Environ. Sci. Technol. 36, 2146–2153.

Munoz, J., Becker, P., 1999. The kelp Gull as bioindicator of

environment chemicals in the Magallan Region. A compar-

ison with other coastal sites in Chile. Sci. Marina 63 (Suppl),

495–502.

Munoz, J., Becker, P.H., Sommer, U., Pacheco, P., Schlatter,

R., 2003. Seabird eggs as bioindicators of chemical con-

tamination in Chile. Environ. Pollut. 126, 123–127.

Newman, J., Becker, J., Blondina, G., Tjeedema, R., 1998.

Quantitation of Aroclors using congener-specific results.

Environ. Toxicol. Chem. 17, 2159–2167.

Palma, H., Alvarez, E., Gutierrez, E., 1998. Compuestos

organoclorados cıclicos en organismos representativos de

la biota del estuario del rıo Valdivia. Bol. Soc. Chil. Quım.

43, 201–211.

Popp, P., Bauer, C., Hauser, B., Keil, P., Wennrich, L., 2003.

Extraction of polycyclic aromatic hydrocarbons and

organochlorine compounds from water: A comparison

between solid-phase microextraction and stir bar sorptive

extraction. J. Separation Sci. 26, 961–967.

Ribes, A., Grimalt, J., Torres Garcia, C.J., Cuevas, E., 2002.

Temperature and organic matter dependence of the distri-

bution of organochlorine compounds in mountain soils

from the Subtropical Atlantic (Teide, Tenerife Island).

Environ. Sci. Technol. 36, 1879–1885.

R. Barra et al. / Chemosphere 58 (2005) 905–915 915

Schultz, D., Petrick, G., Duinker, J., 1989. Complete charac-

terization of polychlorinated biphenyls congeners in com-

mercial Aroclor and Clophen mixtures by multidimensional

gas chromatography—electron capture detection. Environ.

Sci. Technol. 23, 852–859.

Sinkkonen, S., Paasivirta, J., 2000. Degradation half-life times

of PCDDs, PCDFs and PCBs for environmental fate

modeling. Chemosphere 40, 943–949.

Statsoft, Inc., 1997. Statistica for Windows [Computer program

manual]. StatSoft, Tulsa, OK. Available from: <http://

www.statsoft.com>.

UNEP 2003. Regionally based assessment of persistent toxic

chemicals, Global Report. United Nations Environment

Programme, Chemicals division, Available in internet at

www.chem.unep.ch/pts.

Wilcke, W., Krauss, M., Amelung, W., 2002. Carbon isotope

ratio of polycyclic aromatic hydrocarbons (PAHs): evidence

for different sources in tropical and temperate environ-

ments?. Environ. Sci. Technol. 36, 3530–3535.

Wild, S.R., Jones, K., 1995. Polynuclear aromatic hydrocar-

bons in the United Kingdom environment: a preliminary

sources inventory and budget. Environ. Pollut. 88, 91–108.