A Risk Assessment Example for Soil Invertebrates Using Spatially Explicit Agent-Based Models

Melissa Reed, Tania Alvarez, Sonia Chelinho, Valery E Forbes, Alice Johnston, Mattia Meli, Frank Voss, Robert Pastorok

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review


    Current risk assessment methods for measuring the toxicity of plant protection products (PPPs) on soil invertebrates use
    standardized laboratory conditions to determine acute effects on mortality and sublethal effects on reproduction. If an
    unacceptable risk is identified at the lower tier, population-level effects are assessed using semifield and field trials at a
    higher tier because modeling methods for extrapolating available lower-tier information to population effects have not yet
    been implemented. Field trials are expensive, time consuming, and cannot be applied to variable landscape scenarios.
    Mechanistic modeling of the toxicological effects of PPPs on individuals and their responses combined with simulation of
    population-level response shows great potential in fulfilling such a need, aiding ecologically informed extrapolation. Here,
    we introduce and demonstrate the potential of 2 population models for ubiquitous soil invertebrates (collembolans and
    earthworms) as refinement options in current risk assessment. Both are spatially explicit agent-based models (ABMs),
    incorporating individual and landscape variability. The models were used to provide refined risk assessments for different
    application scenarios of a hypothetical pesticide applied to potato crops (full-field spray onto the soil surface [termed
    “overall”], in-furrow, and soil-incorporated pesticide applications). In the refined risk assessment, the population models
    suggest that soil invertebrate populations would likely recover within 1 year after pesticide application, regardless of
    application method. The population modeling for both soil organisms also illustrated that a lower predicted average
    environmental concentration in soil (PECsoil) could potentially lead to greater effects at the population level, depending on
    the spatial heterogeneity of the pesticide and the behavior of the soil organisms. Population-level effects of spatial-temporal
    variations in exposure were elucidated in the refined risk assessment, using ABMs and population-level endpoints while
    yielding outputs that directly address the protection goals. We recommend choosing model outputs that are closely related
    to specific protection goals, using available toxicity data and accepted fate models to the extent possible in parameterizing
    models to minimize additional data needs and testing, evaluating, and documenting models following recent guidance.
    TidsskriftIntegrated Environmental Assessment and Management
    Udgave nummer1
    Sider (fra-til)58-66
    Antal sider9
    StatusUdgivet - 1 jan. 2016

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