Download Summary of workshop «Contaminants in urban food webs

Summary of workshop «Contaminants in urban food webs»
The purpose of the workshop was to improve the national monitoring programs “Contaminants
in an urban fjord”, “Contaminants in Norwegian big lakes” and “Contaminants in terrestrial and
urban environments” and to establish a dialogue/ get input from the research community on
how this can be obtained. A main challenge with these programs is how to provide robust
information on bioaccumulation of new and emerging pollutants. Hence, the most important
topic of discussion was how the monitoring programs should be designed in order to achieve
this objective. In particular the reliability and uncertainty of TMFs relative to other
bioaccumulation metrics for use in national and international regulations were discussed. The
workshop also discussed the choice of species and matrixes used in each program and the
challenges with the food web models that had been used. We also wanted to discuss knowledge
gaps and get inputs on what type of research needed in order to reach the objectives that has
been set for each of these monitoring programs. The workshop was divided in three parts. First
a series of presentations were held, then the participants moved into groups where they
discussed different topics. Conclusions and presentations from the group discussions were then
presented and discussed in plenary. See appendix for further details.
The groups were asked to discuss and conclude on the following questions:
1. How can we improve monitoring of bioaccumulation of contaminants in marine and terrestrial
urban areas?
a. What are the flaws and challenges with the current food web models?
b. Which changes may be recommended for future monitoring (with the same economic
limit)?
i. Which species and types of samples should be included in the program?
ii. Which locations?
iii. Are the goals for the program too ambitious or too narrow minded regarding the
need of data?
c. Which changes may be recommended for the future (with an increased economic limit)?
i. Which species and types of samples should be included in the program?
ii. Which locations?
2. What level of quality are sufficient? Do we need the TMF, or is it enough with the BMF?
a. What are the challenges with the TMF?
b. Is it compatible for all types of chemicals?
c. Which chemicals are particularly challenging?
d. Should we switch to BMF instead?
e. If yes, which changes in study design of the programs could be recommended?
f. Lipophilic vs proteinophilic chemicals: Current research status, and study designs for
capturing them in the monitoring programs?
3. What kind of research are needed in order to reach our goals?
a. What kind of research questions are most important in the context of bioaccumulation
of contaminants in urban food webs?
b. Which parameters and processes are important for understanding how changes in the
abiotic environment influences the accumulation of contaminants in food webs?
c. What kind of existing data could be of use in this context and should be made more
available for future research projects?
In summary, the workshop highlighted several challenges with the existing programs – mostly
regarding the choice of species - and resulted in specific recommendations for the three food
webs. Overall the TMF was considered to be the most robust endpoint for documenting
bioaccumulation and biomagnification.
Even though there are several obstacles with the trophic magnification factor method (TMF),
the general view from the workshop participants was that it should still be used in the
programs. The TMF provides more room for ecological complexity compared to the BMF (bio
magnification factor) and is more ecologically relevant. Although it is possible to extrapolate
from BMF to TMF using mathematical calculations (and vice versa), the BMF is still difficult to
obtain because few species has a one-to-one relationship. Hence, using a BMF does not solve
the challenges with the TMF, and the programs should therefore focus on improving the current
food web models in the context of TMF. The workshop also discussed the challenges with
generating reliable TMFs in more heterogenous environments and the need for including a
reference site in addition to the monitoring sites in urban environments. In areas with more
anthropogenic activity such as urban centers, as well as in more heterogeneous matrixes such
as soil, there may be large differences in pollutant load and composition over short
(geographical) distances. While some argued that reference sites are important and provides a
quality assurance of TMFs generated in such environments, others did not share this view. At
present the monitoring programs exclusively measures pollutant loads in different species of
biota, and the need to also include measurements of pollutant loads in abiotic matrixes such as
sediment and soil was raised. It was argued in particular that such information could provide
valuable information on uptake. It was also suggested that such information could generate
valuable information on the heterogeneity/ variation of the environments under study. Passive
sampling devices were proposed as an additional and possibly useful endpoint to provide insights
on uptake in biota from the surrounding environment.
Another important issue that was discussed was the choice of monitoring/ study sites. A general
view at the workshop was that, it is important to build on the current knowledge, and therefore
keep the existing locations in Oslo and Åmotdalen. However, it was also proposed to include
other urban locations in the future as this would contribute to a better understanding of
pollution challenges in Norwegian urban environments. Tromsø and/or Trondheim). Kautokeino
was suggested as a possible reference site for Tromsø.
The use of nitrogen and carbon stable isotopes are crucial for obtaining a complete ecological
picture, but was it was also argued to include isotopes of sulphur , especially since these
programs are monitoring urban pollution. Delta 34S has been argued to offer additional
separation between habitats and species, and has potential as urban indicator. In addition, the
choice of species should not only be based on trophic level, but also represent different foraging
strategies (specialists, generalists, opportunists, etc). All programs should be better linked to the
abiotic environment and thus include sediment, water and soil samples (preferably using
passive samplers). Extra parallel samples should be stored in the specimen bank. A possible
potential in linking the marine food web together with the terrestrial food web using the herring
gull was also pointed out.
It was adviced to include several trophic levels in the current freshwater food web in Mjøsa.
Similarly, the food web in two other lakes (Femunden and Randsfjorden) should be extended by
another trophic level. Furthermore, it was argued that the program should include additional
lakes in the Arctic.
The marine food web used in the existing Urban fjord programme indicated an incomplete
coverage of trophic levels and unexpected trophic relations, since the species are not directly
linked to each other. The herring gull, in particular, is an outsider with its opportunistic foraging
strategy, and the stable isotope signature links it to the terrestrial system. The food web
including cod (excluding herring gull) shows a more trustworthy TMF (using PCB 153 as a
benchmark), compared to the food web including herring gull. Cod should therefore be
included. The herring gull is still of interest, but mainly as an opportunistic “outsider”. The
oystercatcher could be an option to the herring gull, as it feeds on polychaetes and mussels, and
hence may be more related to the food web.
The terrestrial programme was adviced to keep the current food web: earthworms -> fieldfare > sparrow hawk, but could be improved by including soil samples and tawny owl (which feeds
on both rats and sparrow hawk) as part of the food web model. An optional foodweb consisting
of lichen -> moose/reindeer and/or hare -> wolf, wolverine and/or golden eagle was also
recommended based on peer review published results. An alternative and less expensive option
to monitoring of pollutant loads in soil would be to employ existing data and knowledge on
contaminated soil in Oslo to identify and characterize sampling sites.
Appendix – More detailed summary from the presentations and discussions
Part 1 – From the management’s perspective
Trine Celius (Contaminant regulations and the B-criteria)
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The Stockholm convention has the following criteria:
o (i) Bioconcentration factor (BCF) and/or Bioaccumulation factor (BAF)
 BCF5000 or log Kow5
o (ii) High bioaccumulation in other species (terrestrial and aquatic):
 Biomagnification factor (BMF)
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 Tropic magnification factor (TMF)
o (iii) Monitoring data in biota indicating a bioaccumulation potential
 High levels of the chemical detected at an important level in a food web
or in top predators
 High levels of the chemical detected in Arctic organisms especially top
predators
o Total evaluation based on a weight of evidence approach
REACH has the following criteria:
o B-criteria: BCF is greater that 2000 (aquatic)
o vB-criteria: BCF is greater that 5000 (aquatic)
o All available information (BAF, BMF, TMF) on bioaccumulation shall be
considered in a weight of evidence approach
o Criteria for terrestrial species are under consideration
One major challenge is the substances with the non-classical bioaccumulation:
o Very hydrophoblic, log Kow7
o Big molecules with high molecular weight
o Chemicals that undego biotransformation
o Chemicals that do no accumulate in fat but bind to proteins
o Should they be reported using lipid weight or wet weight?
o Should we measure them using whole body measurement or tissue levels?
Is it enough with the BMF, or should we reach for the TMF?
Bård Nordbø/Eivind Farmen/Norith Eckbo (Monitoring bioaccumulation)
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All monitoring programs (the former Climate and pollution agency’s programs) were
evaluated in 2010-2011 and revised in 2012
The monitoring changed from focusing on industry reference sites, marine and air, long
transport and classical contaminants, to urban areas, new contaminants, population as
source, and food webs
We no longer only need to measure the contaminant concentrations in the environment,
but also methods to measure the properties of contaminants (toxicity and
bioaccumulation)
The marine food web
o Use of data: REACH, Stockholm-convention, OSPAR, national regulations
o Coordination: MILKYS and RID
o Goals:
 What is the source of contaminants in urban fjords?
 Where do the contaminants end up?
 What are the effects of the contaminant levels?
o Future questions:
 Is the Oslofjord representative?
 Should we include or move to other fjords in Norway?
 How can we improve the study design in order to reach our goals?
 Which species should we include next year?
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The freshwater food web
o Use of data: REACH, Stockholm-convention, national regulations, Water
Framework Directive
o Coordination: Norwegian specimen bank, screening program
o Goals:
 What are the contaminant levels and trends in large Norwegian lakes?
 How do the contaminants accumulate in the food web?
 What are the effects of the contaminant levels?
o Future questions:
 Are the selected lakes representative?
 Should we include or move to other lakes in Norway?
 How can we improve the study design in order to reach our goals?
 Which species should we include?
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The terrestrial food web
o Use of data: REACH, Stockholm-convention,national regulations
o Coordination: Norwegian specimen bank, Urban fjord, screening program
o Goals:
 What are the contaminant levels in terrestrial urban ecosystems?
 How do contaminants accumulate in the food web?
 What are the effects of the contaminant levels?
 What is the combined toxicity?
o Future questions:
 Should we include the arctic – Tromsø?
 Which species and locations should we include next year?
 Should we include humans in the food web?
o We should keep in mind the species included in the Norwegian specimen bank
and the other monitoring programs (Rovvilt and Hjortevilt-program) when
choosing species
Part 2 – Experiences with the new programs
Anders Ruus (NIVA) (Contaminants in an urban fjord)
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The results of the stable isotopes suggest that the species collected in the present study
do not constitute a representative food web (species analyzed may not represent
important predator-prey relationships)
o Difficult to conclude on biomagnifying properties
Isotopic signatures suggests the Oslofjord cod as a favourable species to include in the
sampled food web in similar future evaluations of the biomagnifying properties of
(“emerging”) contaminants in the inner Oslofjord, where for instance PCBs can serve as
“benchmark” in the evaluations of biomagnifying properties
o When including cod, PCBs show known properties
The cod should be included in the food web
The herring gull is not part of the food web, but is an interesting species due to its
ecology and should be kept
The results show:
o A significant negative relationship was found between the concentration of
bisphenol A (BPA) and eggshell thickness of herring gull eggs
 Not possible to determine any causal relationships between the BPA
concentrations observed in herring gull eggs and the eggshell thickness,
and future studies will be valuable for indicating if this correlation was a
“random” observation, or if such a relationship may be expected
o A significant positive relationship was observed between trophic level and the
(log) concentration of the cyclic volatile methylsiloxane ‘D5’
 It will be valuable to study the disposition of D5 in the Inner Oslofjord
food web, when the sampled species represent more accurate predatorprey relationships
It might be worthwhile exploring other representatives of the zoo- plankton community
(than krill) in future programmes, maybe copepods
It could be beneficial to include a more comprehensive storm water/surface water
campaign in future programmes, where one can utilize passive samplers (for compounds
where it is possible), for more time integrated measurements
o to attempt to acquire good flow estimates at the storm water sampling sites for
the purpose of calculating total yearly contribution from this source of inputs to
the fjord
Dorte Herzke (NILU) (Contaminants in terrestrial and urban environment)
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The result from the first report (2012 data) show the following load of the various
contaminant group in the investigated species was as follows (on a wet weight basis):
o Golden eagle: sumPCB > toxic metals > sumPFAS > sumPBDE
o Pied flycatcher: sumPCB > sumPBDE
o Rats: Toxic metals >> sumPCB > sumPFAS > sumPBDE
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o Earthworms: Toxic metals >> sumPFAS > sumPCB
The earthworm from Oslo area showed a Sum(MEC/PNECpred) > 1 ranging between 5.9
and 12.6, indicating a risk for predators with earthworm as an important food item
Cadmium contributed most to the estimated risk, followed by PFOS and lead and
mercury
For the other species only limited PNECpred exist, limiting a risk evaluation of combined
exposure
It is positive that the management is including the terrestrial system in contaminant
monitoring, because the terrestrial ecosystem, urban pollution and risk of combined
exposure are little understood
The challenges with the program is primarily the selection of species:
Species should be present both in city and ref sites,
Species should be local
We should avoid scavengers and protected species
And the program has had challenges with logistics under sampling due to many
people/institutions involved
Eirik Fjeld (NIVA) (Contaminants in large Norwegians lakes)
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Coming soon
Igor Eulaers (University of Antwerpen) (Inputs on the terrestrial program)
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This is the first initiatives to systematically biomonitor the Norwegian terrestrial and
urban environment
Aim to account for high spatial heterogeneity in pollution and web food dynamics
o Include Tromsø and/ or Trondheim as additional urban areas. Kautokeino is a
possible reference location to Tromsø
Aim for corner stone species, simplify to food web and food chain
o Contaminant exposure depends on dietary habits, which are flexible among
individuals, and in space and time
Aim for ‘human-relevant’ and ‘typical Norwegian’ species
Aim for long-term monitoring and environmental specimen banking
Aim for standardised practices
Include stable isotopes of sulphur and mixing models
In addition to new contaminants it is important to include legacy contaminants:
o toxicological concern e.g. PCBs, Hg, …
o re-emerging concern e.g. HCB, DDT, …
o benchmarking potentiale.g. CB 153, …
o POPs: PCBs, DDTs, HCB, HCHs, CHLs, PBDEs, HBCDDs
o metals: Cd, Pb, Hg
New contaminants of special concern in terrestrial system:
o previously unknown e.g. TTBP-TAZ, PBDPP, …
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o poorly studied e.g. nBFRs, PFRs, CFRs, ...
o PFASs + FRs + PPCPs: ask for expert advice
The choice of matrix should be consistent among species (interpretation of exposure and
calculation of biomagnification)
o muscle or non-invasive alternatives (blood, feathers, hair)
o egg awareness (invasive, laying order, maternal transfer, …)
o integration with health endpoints
o standard sampling procedures
You should sample individuals because living individuals allow control of confounding
life-history
o hunted individuals may not fit the design
o individuals should be non-migratory
o 10 individuals per experimental unit (may be a good rule to start with)
Species should be:
o Constituents of the same food chain
o Typical dietary habits rather than trophic level
o Ubiquitous at all locations
o Representative of the required spatial scale
Some species could be of special interest regarding:
o human consumption e.g. Moose, game, …
o unique/endangered species e.g. Wolverine, Wolf, …
o international comparison e.g. Peregrine Falcon, …
Logistics considerations:
o Ease of tracking and sampling
o Legal requirements
o Complementary to existing monitoring efforts
Recommended food web 1:
o Earth worms
o Rat (eats earth worms)
o Fieldfare (eats earth worms)
o Sparrow hawk (eats fieldfare)
o Tawny owl (eats rats and sparrow hawk)
Recommended food web 2:
o Lichen
o Moose/reindeer (eats lichen)
o Hare (eats lichen)
o Wolverine (eats moose, reindeer and hare)
o Wolf (eats moose, reindeer and hare)
o Golden eagle (eats moose, reindeer and hare)
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Herring gull, human and pigeon are of interest since they are opportunistic feeders and
may have different contaminants levels and patterns compared to the other species in
the food web
Part 3 – Research needs
Dag Hjermann (NIVA) (Effects of changes in discharges, climate and other factors on coastal
contaminants and their biological consequences (COCO))
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Using already existing data (both monitoring and research data) to investigate how the
distribution of contaminants in the marine ecosystem are influenced by environmental
factors such as climate
Linking these data to population dynamics
Following the contaminants from source to final fate in the ecosystem
Need inputs on what kind of data/other factors should be included in the analyses
Katrine Borgå (TMF, BMF and research needs)
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Borgå was unable to participate, but gave her comments in this summary
Part 4 – Group work and discussion
All 27 participants were divided into three discussion groups.
Results of discussion groups
Group 1 – How to improve the food webs in urban marine and urban terrestrial ecosystems?
Participants: Anders Ruus, Claire Coutris, Jens Vedal, Elisabeth Lie, Torgeir Nygård, Igor Eulaers,
Tomasz Ciesielski, Gunn Lise Haugestøl, Ian Allan, Christina Tolfsen and Norith Eckbo.
1. The group repeated the shortcomings and challenges pointed out by Ruus, Herzke and
Eulaers. In addition, the group also discussed the following:
 Both programs should be better linked to the Specimen bank, and samples from the
programs should be automatically stored in the bank
 Earthworms should be sampled from the upper part of the soil
 It could be useful to measure abiotic concentrations in sediment and soil and/ or to
use semi-permeable membranes as a proxy to provide a better understanding of the
uptake from soil/sediment to the organisms
 That measurements of pollutant loads in eggs, which reflect what pollutants are
transferred from mother to off-spring are not necessarily representative of the
trophic transfer within a food chain and should be accompanied by measurements of
blood and/ or feathers to provide reliable data on bioaccumulation
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That use of migratory species preferably should be avoided as their pollutant load
will not truly reflect the pollutant load at the study site. With regard to the use of
eggs for biomonitoring it was however pointed out that that migratory birds mostly
use energy derived from foraging at the breeding site to produce eggs, but that this
needs to be further verified by actual measurements.
2. Which species, locations and matrixes should we include next year (same economic
limit)?
Marine food web
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Zooplankton (but maybe another species; copepod, instead of krill)
Shrimps
Blue mussel (data can be obtained from MILKYS)
Cod (data and samples can be obtained from MILKYS)
Herring gull should maybe be replaced by Oyster catcher (which feeds on
polychaetes and mussels in the benthic zone) or Common eider (which feeds on blue
mussel)
But Herring gull is also interesting due to high levels of contaminants which may be
linked to effect parameters
Inner Oslofjrod should be kept as location, but it might be a good idea include
Tromsø (priority 1) or Trondheim (priority 2)
Terrestrial food web
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Include data from soil contamination project (Kindergarden project)
Earth worms in the upper level of the soil
Fieldfare (maybe also include nest boxes)
Sparrow hawk, but goshawk is preferred because it does not migrate (which the
sparrow hawk does)
Oslo should be kept in order to follow-up studies, and also due to coordination with
Urban fjord-program and maybe include the Herring gull data in the terrestrial food
web
3. Suggestions for food web and study design with increased economic limit
Marine food web should include:
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other zooplankton species; copepod
passive samplers
Tromsø and Trondheim as additional fjords
in vitro toxicity test on sediment pore water samples
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non-target screening in order to screen for unknown contaminants which may be
essential for assessing toxicity and combined toxicity
Terrestrial food web should include:
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fieldfare and goshawk in Tromsø (pri 1) and Trondheim (pri 2)
Tawny owl and rodents (Norwegian rat)
blood and hair samples from moose and lynx
feathers as an extra tissue type in fieldfare and sparrow hawk
soil samples at the same site at the earth worms
non-target screening for unknown contaminants which may be essential for
assessing toxicity and combined toxicity
Group 2 - What level of quality are sufficient? Do we need the TMF, or is it enough with the
BMF?
Participants: Trine Celius, Dorte Herzke, Anita Evenset, Eivind Farmen, Amanda Poste and Eirik Fjeld
1. What are the challenges with the TMF?
 Non-linearity of a food chain
 Even sampling across trophic levels
 Even number of samples representing different trophic levels
 Mixing of pelagic and bentic representatives within a foodweb
 Mixing of poikilothermic and homothermic organisms within a foodweb
 Comparison between a mix of sample matrixes (whole organism pooled samples
(zooplankton) vs fish liver)
 Comparison of organisms with short vs long life span (zooplankton vs fish)
 Seasonal variation may affect N15 signature
 Many of the challenges mentioned can be dealt with statistically
2. Is it compatible for all types of chemicals?
 Challenging for certain compound such as BDE 209
 Challenges may be resolved by various normalization procedures (to wet weight,
albumin, bile salts etc instead of lipids)
3. Which chemicals are particularly challenging?
 Large molecules, such as BDE209
 Very hydrophobic molecules
 Chemicals that does not necessary partition into fat (per- and poly fluoralkyl substances
(PFAS), BDE-209)
 For chemicals that undergo biotransformation (different species metabolize differently,
species higher up in the food web can have a higher degree of metabolism)
 Metabolite can have a higher potential for bioaccumulation
4. Should we switch to BMF instead?
 BMFs require a strict 1:1 relationship between predator:prey, which is not easy to
identify or commonly found within complex foodwebs
 BMFs require a higher degree of replication, whereas TMF will smoothen differences
across trophic levels.
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But it is possible to use N15 data to calculate BMFs in the absence of a TMF (or a TMF
under 1).
5. If yes, which changes in study design of the programs could be recommended?
 It was generally adviced to stay with a TMF approach, but if changed to BMF, samling
must be designed to a higher degree of replication alongside with careful species
selection (predator:prey)
6. Lipophilic vs proteinophilic chemicals: Current research status, and study designs for capturing
them in the monitoring programs?
 Choice of sample matrix is essential. For instance for PFAS, blood and/or liver enables
improved detection compared to muscle.
Group 3 - What kind of research are needed in order to reach our goals?
Partiscipants: Heli Routti, Dag Hjermann, Tore Høgaasen, Jostein Starrfelt, Sjur Andersen, Morten
Helberg, Bård Nordbø and Ivo Havranek
1. What kind of research questions are most important in the context of bioaccumulation of
contaminants in urban food webs?
2. Which parameters and processes are important for understanding how changes in the abiotic
environment influences the accumulation of contaminants in food webs?
3. What kind of existing data could be of use in this context and should be made more available for
future research projects?