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SETAC Barcelona Session Summaries
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Risk Assessment, Regulation and Public Perception Session Summaries from SETAC Barcelona

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  • Assessment of Risks Posed by Systemic Insecticides to Hymenopteran Pollinators: From Lab via (Semi-) Field to Landscape Scale Testing
    • Fred Heimbach (tier3 solutions) and Richard Schmuck (Bayer CropScience)

      An important point of any regulatory environmental risk assessment concerns the question whether adverse effects observed for individuals under controlled experimental conditions in the laboratory translate into significant (unacceptable) risks for populations in field environments. In field environments, individuals are not homogeneously exposed to contaminants, since the level of contamination often varies from one compartment to another (dilution of exposure), and population structures provide a resilient buffer against losses of individuals (resilience by loss compensation). Some systemic insecticides like nitro-substituted neonicotinoids reveal a very high acute toxicity to bee species, and even minute doses have been shown to cause significant adverse effects to individuals under controlled laboratory or field conditions. The purpose of this session was to capture the risks posed by systemic insecticides to bee species in their natural social and environmental context.

      Twelve platform presentations were delivered in the session with eight presenting findings from differently designed field and field-monitoring studies where domestic honeybees, bumblebees and mason bees were exposed to residues of systemic neonicotinoid insecticides in artificial syrup, in natural pollen or nectar, or in drifted seed dust particles. One presentation examined the influence of these systemic insecticides on the immune system of honeybees, and one introduced a new class of systemic insecticides (diamides), which were shown to not pose an unacceptable risk to bee species. Two presentations introduced modeling approaches to examine our mechanistic understanding of field exposure patterns based on the foraging behavior of honeybees and the dissipation behavior of systemic compounds within the beehive. Another presentation followed up on the importance to adequately consider the ecological consequences of both, using and not using systemic compounds, in regulatory decision-making. 

      Presentations concerning exposure of bee species in field environments included studies with confined (dust particle exposure) and unconfined (exposure to residues in food) bee populations. These presentations demonstrated that exposure to low residues of systemic insecticides either in nectar, pollen, sucrose solution or drifted seed dust particles do not result in observable adverse effects to honeybees, bumblebees or solitary bees (mason bees).  The effects of residues in natural nectar and pollen to managed honeybee colonies, bumblebee colonies and solitary bees were examined in one pair of similar landscapes of 65 km² in size, with controlled treatments in nearly 1,000 ha winter oilseed rape. It was discussed, with considerable disagreement, whether the six test locations within each landscape can be regarded as true replicates. Also, the treatment of the majority of oilseed rape fields in both landscapes with pyrethroids was further challenged, although it was acknowledged that these compounds were classified as non-hazardous to bees and were necessary to ensure the health of the oilseed rape plants, which otherwise would have differed in their attractiveness and nutritional value for the examined bees. Finally, the potential ecological consequences of a suspension of systemic neonicotinoid insecticides and their substitution by less effective products was summarized from a food production and trade-flow perspective, and it was emphasized that the environmental risks of substitutes need to be carefully examined not to risk an even poorer environmental record in the end.

      The session on field evidence-based risk assessment of systemic insecticides was very well attended with over one hundred attendees for several presentations. The key points for the 12 presentations included:

      1. Field and field-monitoring studies provide the most valuable input data for a solid evaluation of risks
      2. Field and field-monitoring studies need to compromise between statistical power (replication) and standardization of environmental conditions (level of control of other impact factors)
      3. Data modeling and weight of evidence approaches are considered as highly supportive tools to reduce uncertainties in interpretation of field data and to make these highly relevant data usable for regulatory decisions
      4. An effective and environmentally protective regulation requires an appropriate integration of field data and a comprehensive consideration of the ecological impacts of both, the use and non-use of (specific) agrochemicals

      Authors’ contact information: fred.heimbach@tier3.de and richard.schmuck@bayer.com

  • Ecological Risk Assessment and Sustainable Management of Contaminated Sediment: Perspectives and Experiences
    • Elisa Bizzotto (Ramboll-Environ), Licia Guzzella (CNR-IRSA) and Mario Carere (Italian Institute of Health)

      This session was aimed to facilitate discussions among scientists, risk assessors and managers working in academia, industry and government to share experiences and approaches to achieving realistic, risk-based decisions for potentially contaminated sediments.

      The European Water Framework Directive (WFD) for the protection of the aquatic environment requires the achievement of “good chemical and ecological status” for all surface water bodies. The assessment of chemical status is based on the comparison of monitoring data with environmental quality standards (EQS) derived at a European level for water and biota and at member state level for sediment. The ecological status is based mainly on evaluation of biological quality elements (e.g., benthic macroinvertebrates). Progress has been made recently towards the development of an EU regulatory framework for sediment risk assessment and management including the derivation and harmonization of sediment quality standards.

      The session was well-attended with more than 120 participants. The main focus of the 6 platform presentations was on approaches and general framework adopted in different EU member states. Four presentations were about application and development of quality guidelines and risk-based benchmark and evaluation of contaminated sediment case studies in Italy (Lake Maggiore), Switzerland (Venoge River), Spain (Bay of Biscay) and Germany (Elbe River). The presentations illustrated approaches and adopted methods, with details on methods for sediment toxicity testing, benthos evaluation and the overall framework for assessment and management.

      One presentation was about a risk assessment framework to support management for dredged materials. The concluding presentation was about risk assessment schemes for prospective sediment toxicity testing in an ecosystem services framework.

      Presentations highlighted challenges related to sediment investigation and assessment (also in relation to EQS set by different member states under the WFD), recognizing the importance of a tiered approach to refine uncertainties (optimizing costs and resources) and the need for more realistic risk assessment to support decision-making. In case of contaminated sediment, management measures may become necessary but need to be based not only on exceedance of EQS but also on ecotoxicological responses and a profound system understanding.

      The results of the ecological risk assessment should be scientifically based and help the decision-makers to select the sustainable measures for the management of contaminated sediment. When meant to support decision-making for remedial action, wrong results may have heavy managing and economical implications (i.e., removal and treatment of high volume of sediments) with possible further deterioration of the aquatic environments.

      Authors’ contact information: ebizzotto@environcorp.com, guzzella@irsa.cnr.it and mario.carere@iss.it

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