Regionalized concentrations and fingerprints of polycyclic aromatic hydrocarbons (PAHs) in German forest soils

doi:10.1016/j.envpol.2015.03.026

Environmental Pollution

Volume 203, August 2015, Pages 31-39

https://doi.org/10.1016/j.envpol.2015.03.026 Get rights and content

Highlights

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Highest PAH concentrations were found relatively close to potential emitters.
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PAH fingerprints show regional-specific distribution patterns.
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Enrichment factors between mineral soils and humic layers depend on humus type.
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Regional sources dominate contents and patterns more than long-range transport.

Abstract

Samples of 474 forest stands in Germany were analysed for concentrations of polycyclic aromatic hydrocarbons (PAHs) in three sampling depths. Enhanced concentrations were mainly found at spots relatively close to densely industrialized and urbanized regions and at some topographically elevated areas. Average enrichment factors between mineral soil and humic layer depend on humus type i.e. decrease from mull via moder to mor. Based on their compound-patterns, the observed samples could be assigned to three main clusters. For some parts of our study area a uniform assignment of samples to clusters over larger regions could be identified. For instance, samples taken at vicinity to brown-coal strip-mining districts are characterized by high relative abundances of low-molecular-weight PAHs. These results suggest that PAHs are more likely originated from local and regional emitters rather than from long-range transport and that specific source-regions can be identified based on PAH fingerprints.

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds which are released to the environment by combustion processes involving biomass or fossil fuels. Due to their persistency and recalcitrance as well as the carcinogenic potential of some homologues, their fate in different compartments of the global ecosystem has been intensely studied (e.g. Jones and de Voogt, 1999, Wilcke, 2000, Srogi, 2007, Ravindra et al., 2008, Křumal et al., 2013).

While relatively high deposition rates of PAHs are expected in vicinity to emitters, especially the low-molecular-weight homologues with enhanced volatility show a significant potential for long-range-transport (e.g. Hung et al., 2005). Consequently, a relatively large number of studies have evaluated PAH pollution in urban environments (e.g. Mielke et al., 2001, Aichner et al., 2007, Liu et al., 2010; and references therein). Studies from more remote areas mostly concentrate on grassland or agricultural areas (e.g. Heywood et al., 2006, Maliszewska-Kordybach et al., 2008, Plaza-Bolaños et al., 2012), while data from forest sites are in many cases only available from selective spots and extensive large-scale studies are relatively rare (Krauss et al., 2000, Weiss et al., 2000, Desaules et al., 2008, Holoubek et al., 2009, Aichner et al., 2013). Soils appear to act as a sink for PAHs, due to the high affinity of those compounds to soil organic matter (SOM) (Sweetman et al., 2005). At forest stands, this effect is enhanced by the canopy scavenging of trees, which increase pollutant fluxes from air to soil, e.g. by litter fall (Horstmann and McLachlan, 1998). Once in the soil, PAHs are susceptible to re-volatilization, reversible sorption to SOM, translocation to deeper soil horizons, mineralization, and aging, i.e. irreversible binding to SOM which decreases bioavailability (Brorström-Lundén and Löfgren, 1998, Cousins et al., 1999, Alexander, 2000, Haritash and Kaushik, 2009, Luo et al., 2012).

Recently, we analysed persistent organic pollutants (POPs), in O horizons on 474 forest stands distributed over Germany in 16 × 16 km grid (Aichner et al., 2013). The results clearly showed that maximum concentrations could be attributed to specific present or historic sources for most compound groups, which included PAHs, polychlorinated biphenyls (PCBs), and several pesticides. For this follow-up study, we further analysed PAH concentrations in the mineral soil, thus adding up to totally three sampling depths (Of/Oh horizon; mineral soil: 0–5 cm and 5–10 cm) and included a more in-depth evaluation of relative PAH abundances. We aim to a) evaluate if specific source-regions are identifiable based on PAH patterns, and b) decipher the processes behind potential variability in depth distribution, considering both PAH fingerprints and concentrations.

Section snippets

Study area

Germany extends between ca. 5.86 and 15.04 °E and 47.27 and 55.06 °N, covering a total area of 357,021 km². It can be segregated in four major topographic units: the Northern German Lowlands, the Central German Uplands, the Alpine Foreland of southern Germany and the Alps in the very south with the Zugspitze as highest point (2962 m) (Fig. 1a). About 30% of the total area is covered by forest (Fig. 1b).

Due to its location in the influence of the Westerlies and the Gulf Stream, the climate is

PAH concentrations

Sum of total 16 EPA-PAH concentrations range from 105 to 14,889 ng/g d.w. in the O horizon (Aichner et al., 2013), from 20 to 9038 ng/g d.w. and from 7 to 4424 ng/g d.w. in the mineral topsoil (0–5 cm and 5–10 cm, respectively) (Table 1, Fig. 2). Thus, average concentrations are decreasing with depth. Nevertheless, ca. 25% of sampling spots show similar or higher concentrations in the mineral soil compared to the organic layer.

In the organic horizon, highest concentrations were found primarily

Influence of humus-type on depth distribution

At most sampling sites PAH concentrations are decreasing with depth (Table 1), while some plots show higher concentrations in the mineral soil compared to the organic layer. Enrichment factors (EF) were calculated as ratios between the PAH concentrations in the lower and the upper soil horizon (Krauss et al., 2000); i.e. the mineral topsoil (0–5 cm) to the O horizon. Fig. 5 illustrates average enrichment factors of PAHs classified by the number of benzene-rings and the humus types mull, moder

Conclusions

In this study, we found clear spatial trends concerning concentrations and fingerprints of PAHs in German forest soils. The spatial distributions of PAH patterns are comparable in different sampling depths while concentrations show some variability between the O horizons and the mineral soils. Generally, PAH concentrations are decreasing with depths at most sampling sites but enrichment factors are dependent from humus type. At mull stands relatively high enrichment factors were measured which

Acknowledgements

This study was conducted within the German National Forest Soil Inventory (BZE II – Bodenzustandserhebung Wald II) and was enabled by the co-operation between the federal and state authorities for forest and environment. Specifically, forest soil samples were taken by the authorities of the German states and provided for this study. We gratefully thank Katja Kaminski and Dino Berners for processing the samples in the BAM laboratory. The authors thank for fruitful discussions with the colleagues

References (42)

C. Achten et al.
Native polycyclic aromatic hydrocarbons (PAH) in coals – a hardly recognized source of environmental contamination
Sci. Total Environ.
(2009)
B. Aichner et al.
Polycyclic aromatic hydrocarbons and polychlorinated biphenyls in urban soils from Kathmandu, Nepal
Org. Geochem.
(2007)
E. Brorström-Lundén et al.
Atmospheric fluxes of persistent semivolatile organic pollutants to a forest ecological system at the Swedish west coast and accumulation in spruce needles
Environ. Pollut.
(1998)
A.K. Haritash et al.
Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review
J. Hazard. Mater.
(2009)
I. Holoubek et al.
Soil burdens of persistent organic pollutants—their levels, fate and risk. Part I. Variation of concentration ranges according to different soil uses and locations
Environ. Pollut.
(2009)
A. Holsten et al.
Evaluation of the performance of meteorological forest fire indices for German federal states
For. Ecol. Manage.
(2013)
M. Horstmann et al.
Atmospheric deposition of semivolatile organic compounds to two forest canopies
Atmos. Environ.
(1998)
H. Hung et al.
Temporal and spatial variabilities of atmospheric POPs in the Canadian Arctic: results from a decade of monitoring
Sci. Total Environ.
(2005)
K.C. Jones et al.
Persistent organic pollutants (POPs): state of the science
Environ. Pollut.
(1999)
S. Jonsson et al.
Degradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils by Fenton's reagent: a multivariate evaluation of the importance of soil characteristics and PAH properties
J. Hazard. Mater.
(2007)

N.R. Khalili et al.

PAH source fingerprints for coke ovens, diesel and gasoline engines, highway tunnels, and wood combustion emissions

Atmos. Environ.

(1995)

M. Krauss et al.

Polycyclic aromatic hydrocarbons and polychlorinated biphenyls in forest soils: depth distribution as indicator of different fate

Environ. Pollut.

(2000)

K. Křumal et al.

Polycyclic aromatic hydrocarbons and hopanes in PM1 aerosols in urban areas

Atmos. Environ.

(2013)

S. Liu et al.

Polycyclic aromatic hydrocarbons in urban soils of different land uses in Beijing, China: distribution, sources and their correlation with the city's urbanization history

J. Hazard. Mater.

(2010)

L. Luo et al.

Relationships between aging of PAHs and soil properties

Environ. Pollut.

(2012)

B. Maliszewska-Kordybach et al.

Monitoring of the total content of polycyclic aromatic hydrocarbons (PAHs) in arable soils in Poland

Chemosphere

(2008)

H.W. Mielke et al.

PAH and metal mixtures in New Orleans soils and sediments

Sci. Total Environ.

(2001)

K. Ravindra et al.

Atmospheric polycyclic aromatic hydrocarbons: source attribution, emission factors and regulation

Atmos. Environ.

(2008)

P. Schmid et al.

Correlation of PCDD/F and PCB concentrations in soil samples from the Swiss soil monitoring network (NABO) to specific parameters of the observation sites

Chemosphere

(2005)

A.J. Sweetman et al.

The role of soil organic carbon in the global cycling of persistent organic pollutants (POPs): interpreting and modelling field data

Chemosphere

(2005)

M. Tobiszewski et al.

PAH diagnostic ratios for the identification of pollution emission sources

Environ. Pollut.

(2012)

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Regionalized concentrations and fingerprints of polycyclic aromatic hydrocarbons (PAHs) in German forest soils

Highlights

Abstract

Introduction

Section snippets

Study area

PAH concentrations

Influence of humus-type on depth distribution

Conclusions

Acknowledgements

Sci. Total Environ.

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Environ. Pollut.

J. Hazard. Mater.

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J. Hazard. Mater.

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