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Selected Issues Associated with the Risk Assessment Process for Pesticides with Persistent, Bioaccumulative, and Toxic Characteristics
Citation:
Selected Issues Associated with the Risk Assessment Process for Pesticides with Persistent, Bioaccumulative, and Toxic Characteristics.
Impact/Purpose:
The purpose of this FIFRA Scientific Advisory Panel meeting is to seek: 1. An independent review of the need to modify the suite of tools, methods and information traditionally used by the Agency to address issues with assessing ecological risks of pesticides with PBT characteristics. Some of these issues include: - Assessing non-aqueous routes of exposure of aquatic organisms (i.e., dietary uptake), - Assessing aquatic organism toxicity from dietary exposure, - Addressing lack of steady-state accumulation in standard laboratory toxicity tests, - Incorporating factors that affect pesticide bioavailability and bioaccumulation (e.g., organic carbon, lipid fraction, food web structure), and - Addressing the challenges associated with the ecological risk assessment of compounds with extremely low water solubility or with potential PBTs having unknown or complex degradate pathways. 2. An independent review of refinements made to the ecological risk assessment methodologies of four example pesticides with varying PBT characteristics, including the suite of methods, models and data used to characterize the risk. 3. Advice on how the Agency should modify its problem formulation process for future ecological risk assessments involving pesticides with PBT characteristics, including: - The process for identifying (screening) pesticides for potential PBT concerns (i.e., available data, triggers and assumptions regarding total residues of concern), - The scope of risk assessment issues that the Agency should consider for pesticides with combined PBT attributes, and - The existing suite of alternative models, methods and data the Agency should consider for addressing issues related to pesticide persistence, bioaccumulation and toxicity. 4. Advice for prioritizing the development of new models, methods, and information for addressing PBT issues (e.g., bioaccumulation in terrestrial food webs, assessment of long range transport), which would become the subject of future, topic-specific SAP reviews.
Description:
This Scientific Advisory Panel meeting will address selected scientific issues associated with assessing the potential ecological risks resulting from use of a pesticide active ingredient which has persistent, bioaccumulative, and toxic (PBT) characteristics. EPA will pose specific charge questions to the SAP on issues involving: - The range and combination of characteristics of persistence, bioaccumulation, and toxicity that should employ a modified approach to ecological risk assessment; - The need for changes to the conceptual model used to evaluate the potential ecological effects of pesticides with varying P and B characteristics; - Toxicity endpoints and methods OPP should consider when assessing pesticides with varying P and B characteristics; - Pathways of potential exposure that should be considered in assessing the ecological risks of a pesticide with varying P and B characteristics; - Data and model(s) appropriate for estimating and characterizing bioaccumulation and estimating steady and non-steady state pesticide residue concentrations in biota; - Data and model(s) appropriate for estimating and characterizing environmental fate in soil, water and sediment; and - Data and model(s) most appropriate for assessing exposure to biota through multiple pathways. The Office of Pesticides Programs (OPP) has recently completed ecological risk assessments on several pesticides with varying P and B characteristics. OPP will draw on information and analyses from these assessments to illustrate the evolving approach OPP is using to address selected issues and how differences across chemicals – for example, in terms of data, characteristics, and available models – influence OPP’s approaches. This meeting with the SAP is the first of what OPP anticipates will be several meetings over the next few years to improve OPP’s evolving approach to evaluating pesticides with varying P and B characteristics.