Use of sediment quality criteria for the assessment ... - Oekotoxzentrum

Use of sediment quality criteria for the
assessment of sediment toxicity : Applicability to
Switzerland
First report in the Project
“Assessment of Swiss sediment toxicity”
August 2010

Project Team
R. FLÜCK
Centre Suisse d’écotoxicologie appliquée Eawag/EPFL
EPFL-ENAC-IIE-GE, Station 2 (GR B0 391). CH-1015 Lausanne
+41 (0)21 693 37 85. rebecca.flueck@oekotoxzentrum.ch
S. CAMPICHE
Centre Suisse d’écotoxicologie appliquée Eawag/EPFL
EPFL-ENAC-IIE-GE, Station 2 (GR B0 391). CH-1015 Lausanne
+41 (0)21 693 62 58. sophie.campiche@oekotoxzentrum.ch
N. CHÈVRE
IMG-CAM - Faculté des Géosciences et de l'environnement
Université de Lausanne, Anthropole 1124. CH-1015 Lausanne
+41 (0)21 692 3557. nathalie.chevre@unil.ch
F. DE ALENCASTRO
EPFL ENAC IIE GR-CEL GR A1 382 Station 2
CH-1015 Lausanne
+41 (0)21 693 27 29. felippe.dealencastro@epfl.ch
B. FERRARI
Cemagref - Laboratoire d'écotoxicologie
3 bis, quai Chauveau. F-69336 Lyon Cedex 9
+33 (4)72 20 86 24. benoit.ferrari@cemagref.fr
S. SANTIAGO
Soluval Santiago
Rue Edouard-Dubied 2. CH-Couvet
+41 (0)32 863 43 60. ssantiago@bluewin.ch

Foreword
Both river and lake sediments are important compartments of the aquatic ecosystems as they
provide habitat and shelter for many organisms. However, sediments also act as a long-term source
of contamination, as pollutants can be temporarily unavailable for uptake when bound to particles
and so gradually released to the aquatic phase. Many benthic and epibenthic organisms which
represent much of the lower trophic levels may then be exposed to these substances. Adverse
effects such as changes in benthic community structure or population decline have been reported. In
Switzerland, sediments are considered as part of the surface waters. According to the Ordinance on
waters protection (OEaux, 1998), sediments should not accumulate any persistent pollutants in order
to protect the aquatic life. However, contaminants analyses and studies on their toxicity potential are
not often undertaken. In addition, recommendations for the characterisation of sediment are lacking
and quality criteria missing.
The present document is the first step of a project aiming at elaborating recommendations for the
assessment of sediment toxicity in Switzerland. We would like to present here a review and synthesis
of the current methods used in Europe and worldwide for the assessment of sediment quality as well
as some example of values to illustrate this point. This document aims to provide a basis for
discussion to help experts and stakeholders taking decisions regarding the choice and applicability of
sediment quality criteria to Switzerland. The proposed approach mainly refers here to sediment in
situ characterisation and does not aim at discussing sediment management in details for the
moment, which can be the purpose of a next document.
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Index
Foreword
…………………………………………..…...1
I- Background …………………………………………..…...3
i. Introduction …………………………………………..…...3
ii. Problem Statement
iii. Aim of the project
…………………………………………..…...3
…………………………………………..…...5
II. Sediment quality criteria: state-of-the-art
…………………………………………..…...6
i. Methods of derivation …………………………………………..…...6
The background level and reference condition approaches………………………………6
The theoretical approach: equilibrium partitioning ………………………………6
The effects-doses relationships approach …………………………………………..…...7
The assessment factors approach …………………………………………..…...8
The consensus approach
…………………………………………..…...8
The harmonised European approach within the Water Framework Directive…………..8
ii. Practical use of sediment quality criteria
…………………………………………..…...9
III. Sediment quality criteria: example of values
……………………………………………...10
IV. Discussion, conclusion and perspectives
……………………………………………...11
References
……………………………………………...16
List of figure and tables:
Figure1: Holistic approach for sediment quality assessment and associated possibilities of application ...…...5
Table 1: List of principal sediment quality criteria used Europe or world –wide. ……………………13
Table 2: Examples of sediment quality criteria values. ……………………………………………...14
Table 3: Examples of measured concentrations in Switzerland. ………………..……………………15
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I- I. Background
i. Introduction
Sediments are deposits found at the bottom of aquatic environments. They are made up of particular matters
which are of different size, form and mineralogical composition. These matters can originate either from soil
particles transported by fluvial processes, runoff and wind (terrigenous sediment), or they can result from
decomposition of organisms’ debris (organogenous or biogenous sediment). In addition, sediment particles
present variability in grain-size; the size fraction larger than sand, which measures between 0.02 and 0.20 mm,
is collectively called gravel and the size fraction smaller than sand (silt and clay) is collectively called mud. This
size variability will explain the repartition of the particles within a river flow. Indeed sediment particles can be
either in the flow as suspended matter because of important upwards velocity or deposited if the settling
velocity is stronger. As certain chemicals can adsorb to particular matter, they will also be found in these
different locations. Consequently aquatic life may be affected by contaminants though sediment contact and/or
ingestion and interstitial or surface water contact or uptake. Chemicals in suspended matter represent generally
the current pollution whereas the deeper layers of sediment stand for the historical contamination. The first
layers of sediment seems then to be the most relevant part to assess as it accounts for newly deposited matter
which will be the major feeding source and/or contact substrate for sediment-dwelling organisms.
Sediment, which shows variability in time and space, is thus an essential, integral and dynamic part of our river
basins (SedNet, 2006) because of its role of both shelter for many organisms and long-term source of
pollutants. It is part of the water continuum and should not be neglected as its pollution 1 can be source of
deleterious pressures that have to be considered in the monitoring of aquatic ecosystems.
ii. Problem statement
Nowadays, sediment quality assessment methods used in Europe and worldwide, mainly rely on a chemical
approach, i.e. total environmental concentrations are measured (concentrations can also be predicted) and
then compared to available reference, target, recommended or quality values.
In Switzerland there are still no trigger values on pollutants in sediments and there is only little systematic
analysis of the sediment load, which complicates the definition and identification of polluted river sections
(BMG, 2007). Nevertheless, some sediment contamination studies have been reported and the following
examples can be cited:
- The famous accident of the “Schweizerhalle” in Basel in 1986 caused important Hg and Cd
contamination in the Rhine, although the situation seems to have improved much.
- Rivers close to shooting ranges can show heavy lead and antimony pollution (Umwelt Aargau N°37,
2007). Decontamination actions and enhancement of these infrastructures have been undertaken to
find a solution for this kind of problem.
- According to a publication of the Office for Water from canton Zürich about water quality of lakes,
surface and underground waters, sediments present important contamination with Cu and Zn.
- The International Commission for the Protection of Lake Geneva (CIPEL) and the Forel Institute
(University of Geneva) showed that the Vidy Bay, in Lausanne, is highly contaminated by heavy metals
(www.cipel.org).
1 We usually talk about contamination when chemicals found in the sediment are not usually found there or when they are found in higher
quantities than natural background concentrations. Contamination can be distinguished from the word pollution which is used when
sediment contamination results in deleterious biological effects (according to Chapman, 2007).
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- Sediments of hydroelectric plants reservoirs, like for example in the site of Verbois on the Rhône (GE),
are monitored in term of quantity but also in term of quality. In case of an evacuation need, toxicity
potential associated to metallic pollution of sediments may be investigated (www.rhone-geneve.ch, and
Institut Forel, 2003, 2010). Sediments of dams’ reservoirs have also been investigated downstream
from urban areas (Wildi et al., 2004) showing high metal contamination.
Currently, the emphasis seems thus to be put on heavy metal compounds although Switzerland should also
demonstrate interest in organic substances, that can be found in sediments, as the country signed the
Convention of Stockholm on persistent organic pollutants (POPs) 2 . Some examples on polycyclic aromatic
hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) sediment contaminations can be found anyway. As
an example we can cite PCBs pollution in the River Sarine, where in 2008 measurement of 53 sediment
samples gave a mean value of 1.34 mg/kg (sum of 6 PCBs). In Fribourg, the dump site of “La Pila” is an
important source of POPs, namely PCBs in the Birse River. Associated to this pollution, fish were found to
accumulate PCBs in their cells which can represent a hazard when they are consummated (Schmidt et al.,
2010). Within new emerging substances, nanoparticles could be interesting to consider because these
chemicals could present toxicity risk as they are said to be trapped in sediment particles.
This lack of trigger values to assess sediment quality is maybe resulting from the fact that no true legal base
regarding sediment protection has yet been decreed in Switzerland, as it is already the case, for over a decade,
in the water, for heavy metals and pesticides (OEaux, 1998) and in the soil compartment for heavy metals
(OSol, 1998). Despite this lack of a proper legislation, sediment and suspended matter are mentioned in the
Ordinance of Waters Protection (OEaux, 1998). Other texts, like the Ordinance on waste treatment (OTD,
1990), Dredging of lake sediments in harbours and waterways (1995), Ordinance on soil protection (OSol,
1998) and Directive on excavations materials (1999) focus principally the management of sediments. They
present recommendations in term of the “future” of sediments, when considered as a waste or excavation
material. Indeed, objective or quality values are given in OSol (soil indicative values) and the Directive on
excavations materials (U- and T-values), which are regularly used to assess the pollution of sediments, and
which mainly help in decision making concerning sediment management, like sediment dredging. There is then
an obvious lack in adequate values for in situ sediment characterisation.
Actually, some quality criteria for in situ sediment characterisation are currently used in Switzerland, like the
reference objectives of the International Commission for the Protection of the Rhine (ICPR). These references
objectives exist for 6 metals (Cd, Cu, Hg, Ni, Pb and Zn) in sediment or suspended matter whereas for organic
pollutants (Benzo(a)pyren, HCB, PCB 153 and sum of 7 PCBs) values have been derived from reference
objectives fixed for the water compartment. As long as the values of references objectives are not exceeded,
the protection of aquatic life, water supply, human fish consumption and the use of Rhine sediments are
guaranteed (CIPR, 2003). ICPR values are routinely applied, but only by cantons within the Swiss Rhine
watershed, as a comparison to measured environmental concentrations. Measured environmental
concentrations are also often compared with the “Swiss rivers median concentrations” which are median
contaminant concentrations in sediments (fine particles

iii. Aim of the project
The use of quality criteria to assess sediment toxicity could represent a simple and time effective tool for canton
regulators for the interpretation of measured environmental concentrations. However, as noticed previously,
and more examples will be given below, several quality criteria exist and/or are already used in Switzerland.
There is thus a need to fixedly define values, the most pertinent, to refer to, so that harmonisation in
Switzerland is obtained for this point. To help in this way, this present document gives a worldwide overview
and a discussion of the diversity of existing methods used for the definition of these values (Parts II. and IV.,
respectively). A comparison between values was also realised (Part III.). This state-of-the-art will hopefully
provide a basis for discussion to help experts and stakeholders taking decisions regarding the choice and
applicability of sediment quality criteria to Switzerland.
At this step, it is important to distinguish two kinds of approaches concerning sediment quality assessment:
sediment management and sediment “compliance checking”. The first approach aims at characterising
sediment pollution in order to take a decision in its dredging and/or treatment or predict impacts of dredging or
dilution (e.g. values used for excavation materials or OSol indicative values). The second approach aims at
characterising in situ sediments and should be included in the monitoring of surface waters, as evaluation of
sediment toxicity could bring useful information for the understanding of hazard to aquatic ecosystems.
The present document principally focuses on in situ sediment characterisation using sediment quality criteria
(Figure 1, grey-highlighted cells). Further discussions on sampling strategies, applying of bioassays and
biological indexes, worldwide recognised as beneficial for assessment, will follow in further documents, aiming
at finally making available recommendations on how to globally evaluate and characterise sediments in term of
chemical exposition hazard and toxic effects on benthic organisms.
Triad approach 3 for the assessment of sediment quality
Physical and chemical
characterisation
Analysis of chemical concentrations
in whole sediment and comparison
to a quality criterion.
Grain-size (silt, clay, sand)
Total organic carbon
Bioavailability...
Compliance checking in aquatic
ecosystems monitoring
Biological surveys
Use of biological indexes:
- Standard Global Biological
Index
- IOBS Index (Oligochetae
communauty index)
- MakroIndex (Cf. Swiss Modular
Stepwise Procedure)…
Sampling strategies
(Manipulation, pre-treatment, storing, conservation…)
Possibilities of application
Ecotoxicological tests
Depending on the studied fractions,
bioassays can be used:
- Whole sediment: C. riparius
(Insect), H. azteca (Crustacean)
- Sediment extracts: V. fischeri
(Bacteria), D. magna (Crustacean)…
Also possible in situ.
Management of sediments
Figure 1: Holistic approach for sediment quality assessment and associated possibilities of application.
3 The triad approach, which was first proposed by Chapman, 1990, aims at gathering several lines of
investigations to assure proof of evidence in sediment quality assessment.
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II- Sediment quality criteria: state-of-the-art
Sediment quality criteria are numerical chemical concentrations intended to be either protective to biological
resources or predictive of adverse effects to those resources, or both (Wenning et al., 2005). In other words,
they provide scientific benchmarks, or reference points, for evaluating the potential for observing adverse
biological effects in aquatic systems (CCME, 1999). Sediment quality criteria can be used for example to
classify sediment samples with regard to their toxic potential, identify problematic contaminants, put priorities
on areas, based on the frequency and degree of which values are exceeded.
i. Methods of derivation
The overview of sediment quality criteria in Europe and further informed us that harmonisation is lacking and
that the existence of different sediment quality criteria is mainly due to the existence of diverse methods of
derivation. Most of the current used sediment quality criteria, which are defined for a region, a country or in
case of international commissions, can be found in Table 1. Among these criteria, different derivation methods
have been noticed and are detailed below.
The background level and reference condition approaches
The background level approach gives median concentration according to the geochemistry of an area. This
was historically the first method used to derive sediment quality criteria. Data on geochemical background are
usually easily available and can be found for example on the website of the Forum of the European Geological
Surveys (FOREGS; http://www.gtk.fi/publ/foregsatlas/index.php, 2010), where a geochemical atlas of Europe
gives measured concentrations of metallic trace elements. Values for Switzerland are for example of 22.9 +/-
7.8 mg/kg dry weight (mean +/- standard deviation) for Ni, 17.9 +/- 7.4 for Cu and 80.1 +/- 59.5 for Zn (10
sampling points).
As an example of application, background concentration is taken into account for metals in Europe in the
development of Environmental Quality Standards for sediments (QS sed ). QS sed equals background
concentration added to a Maximum Permissible Addition (MPA) which is derived through a theoretical or
empirical method (see below).
Close to this approach, the so-called reference condition approach is, or was widely used in Europe; reference
values are measured in non polluted reference sites. In Belgium, for example, the Flemish Environmental
Protection Agency published reference values (RV). These reference values are means of environmental
concentrations (for metals, sum of PAHs and PCBs, non-polar hydrocarbons…) measured in 12 sites being
part of a monitoring program (every four years) and which have been chosen for their good biological status.
Examples of some environmental concentrations measured in Swiss rivers or lakes sediments can be found in
Table 3.
The theoretical approach: equilibrium partitioning
The equilibrium partitioning method is often used to calculate the exposition to and the effects of chemicals on
organisms based on water phase concentrations when toxicity data on dwelling organisms are very limited
(OECD, 1992). Indeed this method is generally used as it is the only way to have prediction on toxicity when no
or very few ecotoxicity data exist for the assessed substance. This theoretically-based approach uses the
hypothesis of the existence of an equilibrium in the distribution of contaminants between the 3 main phases:
interstitial water, sediment / suspended matter and biota. Moreover this method accounts for differences in
bioavailability (Di Toro et al., 1991). Base calculation formula is:
Sediment Quality Criteria = Kp * Water Quality Criteria
where Kp is the coefficient of partition which can be derived theoretically or calculated from
field studies (OECD, 1992).
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The Environmental Protection Agency of the USA (USEPA) recently published a guideline for the derivation of
sediment screening benchmarks (SSB) with this method for metals in mixtures. For unique substances, SSB
values originate from several method derivations or previous published criteria (see Table 1).
Some adaptation of the above formula exists. For example, the Dutch environmental protection agency
normalised their values to the organic content (loss of ignition) and the grain size of the sediment. Integrating
those important parameters of sediment increases the environmental pertinence of sediment quality criteria as
variability in geochemical proprieties can widely change the bioavailability of contaminants.
An alternative method to the equilibrium partitioning could be the evaluation of interstitial water quality. In that
case, interstitial chemical concentration is measured instead of being predicted through the equilibrium
partitioning model. This approach suffers from several limitations as it uses only a water extract of the sediment
and the European Commission (EC, 2003) concluded that only whole sediment tests with benthic organisms
are appropriate for a pertinent evaluation of risks associated with contaminated sediments.
The effects-doses relationships approach
More and more data on toxic effects to benthic organisms are available and enable the use of an empirical
method based on effects-doses relationships. Effect-dose relationships approach, or statistical or frequencybased
method, consists in establishing relationships between sediment contamination (total concentration of
the target chemical) and toxic responses of benthic organisms. The effects data on organisms are obtained
from laboratory and/or field assays. In laboratory natural or synthetic sediments can be “spiked” (sediment is
contaminated with the contaminant of interest).
The United States of America were the firsts to give such values. The original method is the one from the
National Status Trends Program (NSTP, early 1990s). They set a database combining marine and freshwater
effects values against measured contaminant concentrations. After the demand of Canada to include data from
their country, the still-used databank Biological Effects Database for Sediments (BEDS) was created. Contrary
to the initial approach, in BEDS data on freshwater and marine sediments are treated separately. Furthermore,
data are classified in two groups, data with effects (E) and data without effects (WE), whereas the NSTP did not
differentiate them. Data without effects were included because one considered that they procure relevant
information for the definition of relationship between contaminants and biological response (MacDonald, 1994).
For Canada, two values were defined: TEL i.e. threshold effect level (the so called ISQG) and PEL i.e.
predicted effect level. Formulations for the calculations of TEL and PEL are:
TEL = √ (E15xWE50)
PEL = √ (E50xWE85)
E i = i th percentiles of Effects data;
WE j = j th percentile of Without Effects data.
Numbers of percentile have been chosen empirically.
Some substances are rich in term of available toxicity information and effect concentration data obtained from
several benthic species of different trophic levels. In that case, an extrapolation approach, the method of
Species Sensitivity Distribution (SSD) can be used and should be privileged. SSD assembles single-species
toxicity data, usually No Observed Effect Concentrations (NOEC), in a log-normal or log-logistic distribution, in
order to predict a Hazardous Concentration (HCp). Under this concentration, 100-p % of species in a
community or region of concern is assured to be protected, contamination affecting only a certain percentage
(p) of most sensitive species. Usually HC 5 is employed, for which a minimum of 10 NOECs from at least 8
different taxonomic groups are required. Lack of data on sediment chronic tests hasn’t allowed yet the definition
of many Hazardous Concentrations for freshwater sediments whereas this method has been much more used
for the derivation of water quality criteria. With this approach the relevance of the calculated value is assured by
decreasing the uncertainty, as we gather maximum information and proof weight-of-evidence. This method was
first developed in the Netherlands in 2000.
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The assessment factors approach
As for the derivation of water quality criteria, the application of an assessment factor (AF) is often used to
derive quality criteria for sediments. This method is applied when NOEC (No Observed Effect Concentration) or
EC10 (Effect Concentration 10) values are available resulting from chronic assays’ dose-response
relationships. The assessment factor approach consists in a numerical adjustment used to extrapolate from
experimentally determined dose response relationships to estimate the substance exposure at and above
which adverse effects may occur (http://www.iupac.org/publications/ci/2001/march/risk_assessment.html). It will
reduce the lowest obtained effect concentration value by dividing it by a factor ranging generally from 2 to 100
or sometimes 1000. The assessment factor will take into account the intra-species to inter-species
extrapolation, the long term/short term extrapolation and the laboratory to in situ extrapolation, among others. It
will also compensate the limitation in data quantity shortness. As an example, in the Technical Guidance
Document on risk assessment which comes with the Water Framework Directive (EC, 2003), the following
assessment factors are used according to the available data:
Available test result
Assessment factor
One long-term test (NOEC or EC10) 100
Two long-term tests (NOEC or EC10) with species representing different living and feeding
conditions
Three long-term tests (NOEC or EC10) with species representing different living and feeding
conditions
50
10
The consensus approach
Consensus-based sediment quality criteria are calculated mean values of effect-based criteria published by
several authors and institutions and which are close to each other. It allows the derivation of a unique sediment
quality criterion per substance. This approach was notably introduced by MacDonald in the USA (McDonald et
al., 2000) who calculated the geometric means from different values such as
- Equilibrium partitioning-based sediment quality levels,
- ERLs, LELs, TELs, METs for the derivation of a Threshold Effect Concentration (TEC) 4
- SELs, ERMs and PELs for Predicted Effect Concentration (PEC) 5 .
Values were derived for a list of 28 chemicals (8 metals, PCBs, PAHs and organochlorine pesticides). TEC and
PEC values are generally used over the world and in Switzerland one refer also often to them.
The harmonised European approach within the Water Framework Directive (WFD)
At its establishment in 2000, the WFD (2000/60/CE) did not address specifically to sediment monitoring and
this compartment was literally ignored. But, according to Förstner, 2007 concerning a proposition to the
European Commission, an insight has been brought that sediment should no longer be neglected in this
context. Afterwards, and principally thanks to the elaboration of SedNet 6 , problems of sediment pollution are
taken into account in Europe. According to the European Commission (EC, 2010), for the purpose of trend
monitoring, sediment, or alternatively suspended matter, and biota are the most suitable matrices for many
substances because they integrate, in time and space, the pollution in a specific water body; the changes of
pollution in these compartments are not as fast as in the water column and long-term comparisons can be
made. The Directive of priority substances (2008/105/EC) gives an indication of the chemicals that should be
taken into consideration for trend monitoring as well as for the frequency of monitoring of those substances.
Thirty three priority substances and eight other pollutants are considered.
The publication of the Technical Guidance Document on Risk Assessment (EC, 2003) gives also methods to
derive Environmental Quality Standards (EQS). For sediments, according to the amount of available data on
benthic organisms, we will either apply the theoretical method if no toxic data exist (using preferentially an
4 ERL: effects range low; LEL: lowest effect level; TEL: threshold effect level; MET: minimal effect threshold. Those values were derived by
a statistical approach based on effects-doses relationships.
5 SEL: severe effect level; ERM: effects range median; PEL: probable effect level. Those values were derived by a statistical approach
based on effects-doses relationships.
6 SedNet is a European network aiming at incorporating sediment issues and knowledge into European strategies to support the
achievement of a good environmental status and to develop new tools for sediment management (www.sednet.org).
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experimental coefficient of partition) or the assessment factor approach if data on benthic organisms are
available. But ideally Species Sensitivity Distributions should be employed when possible. PNEC sed are then
defined and field data will afterwards be required for the validation and the definition of a QS sed .
The International Commission for the Protection of the Rhine (ICPR) aims also at deriving its reference
objectives like QS sed . QS have been derived for the 14 significant pollutants for water whereas for the sediment
compartment, only 2 values have been derived until now, for zinc (use of the AF and ARA) and dibutyltin (EqP).
The lack of toxic data on benthic organisms explains this delay in the definition of sediment quality standards.
ii. Practical use of sediment quality criteria
The existence of quality criteria is very useful as it permits to easily calculate a quotient between a measured
(or predicted) environmental concentration and a quality criteria value for a chemical (see formula below).
Qs i = MEC i / SQC i
Qs i = calculated quotient for substance i in sediment
MEC i = measured environmental concentration (in total sediment) for substance i
SQC i = sediment quality criteria for substance i
According to the obtained result, decision can be taken in a short time. If the quotient result is below 1, toxicity
risk of the sediment would be said as negligible whereas if this quotient is higher than 1, the threshold value is
exceeded which indicates a possible hazard for aquatic life. In case of compliance checking, the quotient can
be used to compare different studied sites for their content in a pollutant (for example, up- and down-stream of
an investigated source of pollution) or to define priority substances.
In the sediment management approach, such quotient is often used to help in decision making; depending on
the range of exceedance, sediment will be let in place, dredged or diluted for example.
The Q PEC value is often used meaning that measured concentrations are compared to the values of
MacDonald’s Probable Effect Concentrations. This quotient is applied for example for the evaluation of
sediment toxicity in the dam reservoir of Verbois (GE). No system of classification based on this quotient has
yet been validated but published studies are available (for example, Cemagref & ENTPE, 2001).
Pollutants in environmental sediments being almost always present in mixtures, multi-contaminants toxicity
should also be investigated. Therefore, although Qs i values are independent of eventual presence of other
contaminants, which could be source of interactions (antagonism, additivity, and synergism), calculation of a
mean quotient has been proposed:
Qs m =∑Qs i / n
Qs m = mean quotient in sediment
∑Qs i= sum of Qs i
n = number of calculated quotients
In applied sediment ecotoxicology, such mean quotients have been developed mainly in the domain of
sediment management. As an example, for French waterways, triggers values, named S1, have been
published (Voies Navigable de France, 2005) and decreed. Those values are then used to calculate a Qs and
finally a median quotient Qs m . Recommendations for the interpretation of Qs m in term of sediment toxicity are:
• If Qs m < 0.1, the risk is said negligible. Excavation materials can be manipulated without any specific
constrain.
• If 0.1 < Qs m < 0.5, the risk is said low, but the non-hazard of sediments has to be checked.
• If Qs m > 0.5, the risk is non negligible and there is a need of a detailed diagnosis.
This classification may be an interesting approach, but is maybe more applicable by sediment managers.
Pertinence of such integration is questionable. Even if mean quotient value could be source of interesting
information when mixtures of same mechanism chemicals occurs, underestimation of hazard due to chemicals
presenting synergism actions could happen. Another possibility is the calculation of a total quotient (sum of Qs i )
but the pertinence of adding quotients from different substances needs more evidence and we should also
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cautiously consider synergism and antagonism interactions. Furthermore it appears clear here that the choice
of an adequate sediment quality criteria system has a big importance as decisions will depend on it.
In another practical view, without calculating a quotient, sediment quality criteria can be used as trigger values
for the determination of quality classes. As an example, the quality objectives of the overall evaluation system
of French waters (SEQ-eau) can be cited. Values from the BEDS were used to derive effect-based quality
criteria, TEL and PEL (Table 1). Quality classes have then been delimited based on TEL and PEL values.
This system is currently used in France for the hazard assessment of metals, sum of PCBs or PAHs in
sediments and still needs some development.
Finally, quality criteria and calculated quotients may not be enough to predict a global toxicity of sediment and a
monitoring concept (sampling, analysis) should be coupled with the use of quality criteria and additional lines of
investigations should be recommended, like community surveys and in situ and/or in laboratory bioassays.
III- Sediment quality criteria: example of values
The overview of existing sediment quality criteria and associated derivation methods enabled us to state that
worldwide harmonisation is missing even if some efforts are being done in Europe. This non-harmonisation
leads to the achievement of different reference values for a same chemical. To illustrate this point, some
examples of sediment quality criteria values for chosen substances are given in Table 2. Data are presented for
four heavy metals (Cu, Hg, Ni and Zn), an insecticide (dieldrin), PCBs (sum of 7) and a PAH (anthracene). The
minimal and maximal values obtained for each compound according to the derivation method used are
highlighted in green and red, respectively. It can be noticed that the maximal and minimal values obtained not
always refer to the same sediment quality criteria. For example, the lowest quality criterion (i.e. the most
restrictive) for Cu (0.8 mg/kg d.w) is obtained when calculating a PNEC sed whereas for Hg, the lowest value
(0.17 mg/kg d.w.) is obtained for the Canadian ISQGs. For the exemplified heavy metals, ICPR gives often the
most permissive and PNEC sed the most restrictive values. Furthermore, data derived from a reference condition
approach (Flanders Reference Values) show mean values, indicating that such a method could be an
interesting method and alternative to the others cited approaches. MacDonald’s Threshold Effect
Concentrations (TEC) are also in a mean range compared to other values, illustrating the fact that they are
derived in a consensus aim. We can also remark that data can vary in an important range for the same
substance. For example, there is a factor of 16 between the ICPR RO value (50 mg/kg d.w) and the European
PNEC sed value (3 mg/kg d.w.) for nickel. Furthermore, use of the equilibrium partitioning method or the
assessment factors brings to similar values for nickel (2.94 and 3.20 mg/kg d.w. respectively) whereas very
dissimilar values can be obtained within the same protocol as it is for example the case for Hg and QS sed
values. Indeed, equilibrium partitioning derived value is 0.67 mg/kg d.w. whereas the use of an effect data on
benthic organism (C. riparius) leads to a value of 9.3 mg/kg d.w., that is 14 times higher. Using the criterion of
0.67 mg Hg /kg d.w. could be too restrictive as at 9.3 mg Hg /kg d.w. there seems not to be any risk for benthic
organisms. We should anyway handle this last recommended value cautiously as it is obtained from the result
of only one test with a benthic organism.
Consequently, the use of one or another method can lead to divergent values, depending on the substance and
the available toxicity data. It is thus important to take into account chemical specificity of these criteria as well
as their dependence to data amount.
To be able to discuss the applicability of the described sediment quality criteria to Switzerland, trigger values
used in cantons like soil indicative values (OSol) and Swiss rivers median concentrations are included at the
end of Table 2. It can be remarked that OSol values are in the same range than ICPR RO . Although OSol and
ICRP values don’t aim at protecting the same resources, they are in the same range for Hg and Ni (0.5 and 50
mg/kg d.w., respectively), whereas values for Cu and Zn are around one third lower for OSol. Concerning
Swiss rivers median concentrations, except for Ni, it can be noticed that these values are below the
MacDonald’s Threshold Effect Concentration, which may indicate a pretty good global quality of our rivers in
term of probable effects on benthic organisms, but again values have to be taken cautiously.
Table 3 gives some values examples of measured total concentrations in sediments from a few Swiss case
studies. The two first examples/lines concern sediments of the Lake Geneva. Those values have been obtained
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using a geochemical background approach in order to serve as “natural content level”. It can be noticed that
Vernet (1997) values are similar to ICPR RO . A publication gives mean values for rivers sediments in the Leman
Basin (Favarger, 1990). For an example of sediment metallic but also organic chemicals concentrations in a
dam reservoir, data are presented for the case of the hydroelectric plant of Verbois situated on the Rhône
River. Another example gives mean data from eighteen different water bodies investigated in 2001 in canton
Aargau (AG). Sediments were analysed for their heavy metals content which resulted in concentrations also
close to ICPR RO . Some data from the canton Schaffhausen (personal communication of F. Lang, Amt für
Lebensmittelkontrolle und Umweltschutz SH) are presented; the maximum values obtained are given for each
metal. Finally some data have been added for sediments in the River Aar in the canton of Bern (BE). Important
Cu, Ni and Zn pollutions can be observed with the data presented for Schaffhausen (for example measured
concentration is more than 5 times the ICPR RO for copper) whereas for mercury the value is close to the Swiss
rivers median concentration (0.14 mg/kg d.w.). Mercury seems thus not to be problematic in that case study.
Measured environmental concentrations have always to be interpreted with caution has sampling and
preparation strategies as well as for example the grain-size of the analysed fraction are not always specified.
IV- Discussion, conclusion and perspectives
As illustrated by the quality criteria values given for Cu, Hg, Ni and Zn, big differences can be found for the
same compound between the criteria values according to the approach employed to derive them. For these
substances, the ICPR approach often gives the most permissive values whereas the most restrictive are often
obtained when deriving a PNEC sed . Indeed, ICPR RO values have been developed for the Rhine and its large
affluent rivers, so even if these data are widely used, interrogation can be made about their adequacy to small
local rivers. The use of OSol values, which are very similar to ICPR RO , is also questionable as they aim at
protecting soils. According to these remarks, these quality criteria could be too permissive for a local scale in
the case of rivers sediment compliance checking. Hazardous effects on benthic organisms and the all aquatic
environment could thus be minimised. Effects on benthic organism - based criteria may then be the most
appropriate for our aim of protection. However more data are needed. If we facilitate ecotoxicological studies
through research and harmonisation of sediment bioassays (including problematic sampling and extraction
methods) we will be able to have enough data to provide reliable Species Sensitivity Distribution derived quality
criteria, which integrate a lot of effect-dose relationships data and decrease uncertainty.
Predictive ability of sediment quality criteria also presents matter of discussion as it is still uncertain. Even if
some studies show good predictive ability, when coupling chemical analysis and ecotoxicological testing
(Desrosiers et al., 2010 for instance), false negatives and false positives have been reported; a false positive
occurs when the sediment exceeds a criterion indicating it is toxic, when in fact it is not. A false negative is the
opposite; the sediment is below the criterion, suggesting it is nontoxic, but it is toxic to benthic invertebrates
(Burton, 2002). Due to the reported errors of prediction, among other limitations of the use of sediment quality
criteria, the Netherlands which were one of the first countries in Europe to develop their own effect-based
values are reviewing their methods for the assessment of sediment quality. Sediments will now be envisaged
as an emission source for water pollution and development of integrated assessment approach is planned.
Other limitations of sediment quality criteria include the fact that values are defined for a unique substance, so
criteria are not yet considering effects of mixtures on toxicity, and the fact that they are mostly specific to a
region or river basin. Another underlined problem is the dependence to the sampling strategy (manipulation,
transport, storage…) and the risk that measured concentration may not reflect in situ conditions, i.e. sampling
and manipulation processes could alter sediment chemistry and therefore bioavailability, leading to over or
under estimation of the “real” toxicity. Consequently, sediment quality criteria derived from effects-dose
relationships, being mostly based on laboratory ecotoxicity bioassays, may not be ecologically and
environmentally relevant. In situ investigation through biomonitoring could compensate for this limitation and
should be encouraged.
Contaminant concentrations in total sediment are not always pertinent in term of real bioavailability of pollutants
in this complex matrix. Multiple trapping phases, like organic matter, silt, ferrous oxides or sulphides for
instance can change the speciation of pollutants and then reduce their availability; conversely, re-suspension,
Centre Ecotox Eawag/EPFL 2010
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while dredging, flooding for example can enhance it. Link to this property, a lack of guidance for including in the
derivation of threshold values “non-toxic” disturbances like grain size, organic matter content, re-suspension
risk... has also been noticed.
Sediment quality criteria present anyway a simple, time-effective method to assess, a priori or a posteriori, the
quality and/or toxicity of sediments; they have been developed in order to dispose of a tool for the interpretation
of measured environmental concentrations through an easy comparison or calculation of a quotient. The
pertinence of calculating of a mean or added quotient is anyway still questionable.
For the definition of sediment criteria values to use in Switzerland, one should consider the diversity of methods
of derivation that was illustrated in this document. If we aim to protect benthic organisms living in sediments
that are “in place” (in order to complement the protection of others aquatic species which is assured through the
MSK 7 ), one should follow recommendations of the Technical Guidance Document which comes with the Water
Framework Directive and use PNEC sed validated in QS sed . However no QS sed have yet been validated (only
proposed). Time and toxicity data are needed and research to develop existing- or provide new- test protocols
for sediments should be encouraged. Use of background environmental concentrations, like for example lakes
and rivers means values, could also be proposed in an added risk approach as it has been noticed that
PNEC sed values are the most restrictive and they could bring to much of false positives and may bring to inutile
remediation actions.
In a sediment management point of view, discussions will follow in the future if interest is showed to have
quality criteria developed in this aim. In that case, one could propose to use two values, one trigger value
indicating a contamination (values exceed “normal” concentrations) and another trigger which will indicate a
pollution, i.e the risk of deleterious effects on aquatic organisms (McDonald’s PEC for example or derived from
SSD). It must anyway be clear what the target of protection is.
For both kinds of approaches, either characterization or management, the use of a quotient and its
interpretation as well as its possibility of integration are also questionable. Proposition could be made to link
calculation of this quotient with biological surveys for example and then propose a classification system.
In a further step, some case studies will have to be envisaged to help in the choice of an adequate sediment
criterion system.
Sediment contamination, in time and space, is a hazard for aquatic organisms which cannot be understood only
by dosing chemical concentrations in the water column. As an interesting French project, “DIESE” for “Outils de
Diagnostic de l’Ecotoxicité des Sédiments” aims at developing a tiered approach for the evaluation of
environmental risks applicable to freshwater sediment biocenoses. A battery of tools, namely linking chemical
analysis (exposure) and bioassays (effects) is in development. This project brings evidence that holistic studies
are needed to evaluate toxicity of sediments. In Switzerland, sediments have not been neglected but
harmonised techniques are needed to have a complete biomonitoring protocol. Moreover good knowledge in
hydrodynamics, transport fate of sediments and suspended matter is available in our country. So, one should
take advantage of this body of knowledge because it is useful information when studying sediments. As there is
a growing demand on methods to assess hazard of heavy metals exposition in rivers as well as a need in
methodological recommendations, in term of frequency, sampling and parameters of measures for lakes
sediments (www.cercleau.ch), setting a valid nationwide survey method for the evaluation of heavy metals, and
organic pollutants, in sediments could be of many people’s interest. Indeed several cantons already pointed out
this lack in nationwide-harmonised methodological protocols and the need in enhancing evidences for the
identification of contamination sources. Through discussions with experts and stakeholders interested in
sediment, assessment priorities should be defined in this domain and making available a guideline with
recommendations of adequate methods will support users in their surveys for the assessment of sediment
pollution and toxicity. Discussions will next follow on sampling and analysis strategies of sediments and
afterwards a synthesis on existing bioassays and biological tools will be proposed. Those tools may be
necessary to complete the chemical approach of the use of quality criteria.
7 Modular Stepwise Procedure. Methods for assessing the ecological status of rivers in Switzerland (www.modul-stufen-konzept.ch).
Centre Ecotox Eawag/EPFL 2010
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Table 1: List of principal sediment quality criteria used Europe or world –wide.
Country/Institution Quality criteria Method of derivation
Belgium
Flemish
Environmental
Protection Agency
Europe
Technical Guidance
Document on risk
assessment (EC,
2003)
RV
Reference values
PNEC sed
Predicted No Effect
Concentration
12 reference sites of a monitoring program.
Equilibrium partitioning or assessment factors.
Whole sediment.
Europe
Water
Directive
Framework
QS sed
Quality standard for
sediment
(Drafts)
Organic chemicals
and PPP
- TGD:
EqP or
AF
- SSD
Metals:
- TGD: EqP or AF
- SSD
- Added Risk approach (ARA):
consideration of background
concentration.
The Netherlands
Dutch sediment quality
standards
France
SEQ – eau
Canada
Canadian Council of
Ministers of the
Environment
ICPR
International
Commission for the
Protection of the
Rhine
USA
Environmental
Protection
(Region III)
World-wide used
MacDonald, 2000
Agency
TV Target value
MPC sed
Maximum Permissible
Concentration
IT Intervention value
Quality criteria
2 values
ISQG
Interim Sediment Quality
Guidelines
ICPR RO
Reference objectives
SSB
Sediment Screening
Benchmarks
TEC
Threshold effect
concentration
PEC
Probable effect
concentration
TV = MPC sed/100
MPCsed determined using the TGD-approach applying an
organic content normalization factor.
IT = trigger value for sediment remediation
- If enough data: statistical approach effects-based First
threshold: TEL Second threshold: PEL
- If not enough data: EqP First level: EqP/10 Second level: EqP
Extrapolation to derive criteria for suspended matter: *1.5 for
metals, *2 for organics.
Statistical approach, derived from the National Status Trend
Program, using data from the Biological Effects Database for
Sediments BEDS. TEL Threshold Effect Level and PEL–
Probable Effect Level.
QS sed for 14 significant substances of the Rhine (CIPR, 2009).
Protection of fauna and flora, fishing, drinking water, suspended
matter, sediments and marine environment. EqP for organic
pollutants.
Fine particles.
55 % based on EqP; 20 % consensus-based TEC (McDonald et
al., 2000); 25 % others (11 references).
Geometric means of values, such as
- EqP-based sediment quality levels,
- ERLs, LELs, TELs, METs for TEC
- SELs, ERMs and PELs for PEC.
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Table 2: Examples of sediment quality criteria values.
mg/
kg
dw
Cu Hg Ni Zn
Anthracene
(PAH)
Dieldrin ∑ 7PBCs Notes
Flanders
RV
20 0.10 28 168 - - -
Ref. 1
Trigger value (« x ») for
class 1 (less polluted).
PNECsed
0.80
(AF50,TGD)
0.47
(EqP,TGD)
2.94
(EqP,TGD)
3.20
(NOECTubifex
/AF10)
37
(AF2,TGD)
0.03
(EqP,TGD)
- - Ref. 2
QSsed
Not part of
priority
substances
0.67
(EqP,ARA, Rhine)
9.30
(NOEC-
C.riparius/AF100)
-
(no QS water)
Not part of priority
substances
0.03
(EqP,TGD)
Not part of
priority
substances
-
Ref. 3
Drafts
(priority substances only)
SEQ –
eau
31 0.20 22 120 0.05 0.002 0.06
Ref. 4
« TEL » values
Canadian
ISQGs-
TEL
35.7 0.17 In dev. 123 0.05 0.003 0.03
Ref. 5
Anthracene value is
provisional (from marine
ISQG).
CIPRRO
50 0.50 50
190
(AF+ARA,
priority
substance)
- - 0.03
Trigger value for resuspension
risk
assessment = 4*CIPR RO
TEC
31.6 0.18 22.7 121 0.06 0.002 0.06
Ref. 6
Consensus-based.
Swiss
median
27.4 0.14 30.8 86.3 - - 0.007
Ref. 7
1999-2000
sampling in rivers (n=40)
Osol
40 0.50 50 150 - - - Swiss soil indicative values
Ref. 1 De Cooman et al., 1999. Ref. 2 EC, 2003. Ref. 3 Common Implementation Strategy for the Water
Framework Directive Environmental Quality Standards (EQS) - Substance Data Sheet. Ref. 4 MEDD &
Agences de l’eau, 2003. Ref. 5 CCME, 2002. Ref. 6 McDonald et al., 2000. Ref. 7 Pardos et al., 2003.
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Table 3: Examples of measured concentrations in Switzerland.
mg/
kg
dw
Cu Hg Ni Zn
Anthracene
(PAH)
Dieldrin
∑PBCs
(7)
References
Lake
Geneva
50 0.05 50 100 - - - Vernet, 1977
32 0.015 - - - Arbouille, 1989
Leman
basin’s
rivers
30 0.03 50 60 - - - Favarger, 1990
Verbois
Dam
5.1
32.7

Table 3: Examples of measured concentrations in Switzerland.
References
∝
∝
Arbouille D., Howa H., Span D. & Vernet J.-P., 1989. Étude générale de la pollution par les métaux et répartition des
nutriments dans les sédiments du Léman. Rapport Commission Internationale pour la Protection des Eaux du Léman
contre la pollution (CIPEL). Campagne 1995 ; pp. 239-245.
BMG Engineering AG im Auftrag des Bundesamtes für Umwelt (BAFU), 2007. Sedimente am Hochrhein. Kurzbericht.
∝ Burton J. G. A., 2002. Sediment quality criteria in use around the world. Limnology 3(2): 65-76.
∝
∝
Canadian Council of Ministers of the Environment, 1999. Protocol for the Derivation of Canadian Sediment Quality
Guidelines for the Protection of Aquatic Life. CCME EPC-98.
Canadian Council of Ministers of the Environment (CCME), 2002. Canadian sediment quality guidelines for the
protection of aquatic life: Summary tables. Updated. In: Canadian environmental quality guidelines, 1999, Canadian
Council of Ministers of the Environment, Winnipeg.
∝ Cemagref & ENTPE, 2001. Evaluation écotoxicologique de sédiments contaminés ou de matériaux de dragage. I :
Présentation et justification de la démarche ; II : Présentation des méthodes d’essai ; III : Application au Canal de l’Est
branche Sud ; 163 p.
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
Chapman, P. M., 1990. The sediment quality triad approach to determining pollution-induced degradation. Science of
the Total Environment 97-98: 815-825.
Chapman, P. M., 2007. Determining when contamination is pollution - Weight of evidence determinations for sediments
and effluents. Environment International 33(4): 492-501.
Commission Internationale pour la Protection du Rhin (CIPR), 2009. Détermination de normes de qualité
environnementale pour les substances significatives pour le Rhin. Rapport N° 164 Kaiserin-Augusta-Anlagen 15, D
56068 Coblence.
Commission Internationale pour la Protection du Rhin (CIPR), 2003. Le Rhin remonte la pente. Bilan du Programme
d’Action. Kaiserin-Augusta-Anlagen 15, D 56068 Coblence.
Curdy R., 2010. Proposition d’une méthode pour l’évaluation de la pollution et de la toxicité des sédiments : Application
pour un site sur la rivière Urtenen dans le canton de Berne. Projet de Master. Sciences et Ingénierie. EPFL.
De Cooman W., Florus M., Vangeheluwe M. L., Janssen C. R., Heylen S., DePauw N., Rillaerets E., Meire P. &
Verheyen R., 1999. Sediment characterisation of rivers in Flanders. The Triad approach. Proceedings: CATS 4:
Characterisation and treatment of sediments, 15-17 Sept, Antwerpen, pp 351-367.
Desrosiers M., Babut M. P., Pelletier, M., Bélanger, C., Thibodeau, S. & Martel, L., 2010. Efficiency of Sediment Quality
Guidelines for Predicting Toxicity: The Case of the St. Lawrence River. Integrated Environmental Assessment and
Management 6(2): 225-239.
DiToro, M. D., C. S. Zarba, et al., 1991. Technical basis for establishing sediment quality criteria for nonionic organic
chemicals using equilibrium partitioning. Environmental Toxicology and Chemistry 10(12): 1541-1583.
European Parliament and Council, 2000. Directive 2000/60/EC of the European Parliament and of the Council
establishing a framework for the Community action in the field of water policy"
European Parliament and Council, 2000. DECISION No 2455/2001/EC of 20 November 2001 establishing the list of
priority substances in the field of water policy and amending Directive 2000/60/EC.
European Commission, 2003.Technical Guidance Document on Risk Assessment. In support of Commission Directive
93/67/EEC on Risk Assessment for new notified substances, Commission Regulation (EC) No 1488/94 on Risk
Assessment for existing substances, Directive 98/8/EC of the European Parliament and of the Council concerning the
placing of biocidal products on the market. Part II.
European Commission, 2010. EU guidance on chemical monitoring of sediment and biota under the water framework
directive. Version 7.
Favarger P.-Y., Span D. & Vernet J.-P., 1990. Métaux lourds dans les sédiments des rivières du basin lémanique
suisse. Institut F.-A. Forel, Université de Genève, CH 1290 Versoix.
Förstner, U., 2007. Environmental quality standards (EQS) applicable to sediment and/or biota. Journal of Soils and
Sediments. 7(4): 270.
Institut Forel, 2007. Aspects sédimentaires de la gestion du barrage de Verbois. Loizeau, J.-L. & Wildi, Services
industriels de Genève (SIG).
Institut Forel, 2010. Échantillonnage et analyse de sédiments du réservoir de Verbois : Complément d’investigations.
Loizeau, J.-L. & Wildi, Services industriels de Genève (SIG), 2010.

Table 3: Examples of measured concentrations in Switzerland.
∝
∝
∝
∝
MacDonald D. D., 1994. Approach to the Assessment of Sediment Quality in Florida Coastal Waters. Pour le
Department of Environmental Protection de la Floride. MacDonald Environmental Sciences, Ltd., Ladysmith (C.-B.).
Vol. 1, 123 pages.
MacDonald D., Ingersoll C. & Berger, T., 2000. Development and evaluation of consensus-based sediment quality
guidelines for freshwater ecosystems. Archives of Environmental Contamination and Toxicology. 39(1): 20-31.
Margot J., 2008. Impacts des déversoirs d’orage sur les cours d’eau. Application de la méthodologie STORM et
validation par le biais d’analyses écotoxicologiques et chimiques. Projet de Master. Sciences et Ingénierie. EPFL.
Ministère de l’Environnement et du Développement Durable & Agences françaises de l’eau, 2003. Grilles d’évaluation
version 2.
∝ OECD, 1992. Report of the OECD Workshop on effects assessment of chemicals in sediments. Copenhagen 13 th –
15 th May 1991.
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
∝
Office Fédéral de la Protection de l’Environnement, 1990. Ordonnance du 10 décembre 1990 sur le traitement des
déchets (OTD). No. RS 814.600. Berne, Suisse.
Office Fédéral de la Protection de l’Environnement, 1995. Le dragage de sédiments lacustres dans les ports et voies
navigable. Informations concernant la protection des eaux. No. MGS-19-F. Berne, Suisse.
Office Fédéral de la Protection de l’Environnement, 1998. Ordonnance du 1 er juillet 1998 sur les atteintes portées aux
sols (Osol). No. RS 814.12. Berne, Suisse.
Office Fédéral de la Protection de l’Environnement, 1998. Ordonnance du 28 octobre 1998 sur la protection des eaux
(OEaux). No. RS 814.201. Berne, Suisse.
Office Féféral de la Protection de l’Environnement, 1998. Système modulaire gradué. Informations concernant la
protection des eaux. No. 26. Berne, Suisse.
Office Fédéral de la Protection de l’Environnement, 1999. Directive pour la valorisation, le traitement et le stockage des
matériaux d'excavation et déblais (Directive sur les matériaux d'excavation). No. VU-3003-F. Berne, Suisse.
Pardos M., Dominik J. & Houriet J.-P., 2003. Micropolluants dans les sédiments. Métaux et micropolluants organiques
dans les matières en suspension et sédiments superficiels des grands cours d’eau suisses. Cahier de l’Environnement.
Office fédéral de l’Environnement. Des Forêts et du Paysage, Berne. No. 358.
Schmid P. et al., 2010: Polychlorobiphényles (PCB) dans les eaux en Suisse. Données concernant la contamination
des poissons et des eaux par les PCB et les dioxines : évaluation de la situation. Connaissance de l’environnement n°
1002. Office fédéral de l’environnement, Berne. 104 p.
SedNet, 2006. Sediment Management – an essential element of River Basin Management Plans. Report on the
SedNet Round Table Discussion. Venice, 22-23 Nov.
Vernet J.-P., 1977. Etude de la pollution des sédiments du Léman et du bassin du Rhône. Commission Internationale
pour la Protection des Eaux du Léman contre la Pollution, Lausanne. No. 1976.
Voies navigable de France (VNF), 2005. Guide pour la pratique du dragage.
Wenning R. J., Batley G. E., Ingersoll C. G. and Moore D. W., 2005. Use of Sediment Quality Guidelines & Related
Tools for the Assessment of Contaminated Sediments (SQG). Summary booklet of a SETAC Pellston Workshop.
Wildi W., Dominik J., Loizeau J.-L., Thomas R. L., Favarger P.-Y., Haller L., Perroud A. & Peytremann C., 2004. River,
reservoir and lake sediment contamination by heavy metals downstream from urban areas of Switzerland. Lakes &
Reservoirs: Research and Management. 9: 75-87.
Zürich-Amt für Abfall, Wasser, Energie und Luft, 2006. Wasserqualität der Seen, Fliessgewässer und des
Grundwassers im Kanton Zürich. Statusbericht.