Pesticide risk assessment tool

What are the benefits of using ecological modeling as a pesticide risk assessment tool ... 

What Are the Benefits of Using Ecological Modeling as a Pesticide Risk Assessment Tool ... 

Ecological models were identified as potentially important tools for the following topics in pesticide risk assessment ... 

There are quite a few challenges if EMs are to be established as a widespread tool for pesticide risk assessment, but the overall consensus was that these indeed are challenges, not insurmountable obstacles. Challenges require work and concerted actions, but there was agreement that the potential to obtain better risk assessments warrants the effort required to overcome the challenges. 

This is admittedly a strong statement, but it is based on the acknowledgment of the diversity, complexity, extent, and slow dynamics of most ecosystems. Modeling has become an indispensable tool for ecology and is employed for addressing all kinds of theoretical and applied problems. There is no reason to believe that pesticide risk assessment should be an exception. 

There is a growing need to better characterize the health risk related to occupational and environmental exposure to pesticides. Risk characterization is a basic step in the assessment and management of the health risks related to chemicals (Tordoir and Maroni, 1994). Evaluation of exposure, which may be performed through environmental and biological monitoring, is a fundamental component of risk assessment. Biomarkers are useful tools that may be used in risk assessment to confirm exposure or to quantify it by estimating the internal dose. Besides their use in risk assessment, biomarkers also represent a fundamental tool to improve the effectiveness of medical and epidemiological surveillance. 

In addition to the need for scientific improvements to allow probabilistic risk assessments to be properly performed and interpreted, there also exists a need to educate stakeholders about what the US system for tolerance establishment and monitoring does and does not do. In simplest terms, the US system can be described as a food quality system but not necessarily a food safety system. This results from the fact that the pesticide tolerances are not safety standards but rather exist as enforcement tools that allow an assessment of how well pesticide application regulations are adhered to. Violative residues demonstrate the likelihood of pesticide misuse but should not be considered, in the vast majority of cases, to represent unsafe residues. Safety considerations govern whether or not the use of pesticides on specified commodities will be permitted tolerances, when granted, serve as indicators of good agricultural practices rather than as toxicological benchmarks. 

In conclusion, understanding the biotransformation of pesticides is a useful tool in determining species dependent and mechanistic effects of these compounds in fish and helps to reduce uncertainty in ecological risk assessment strategies. 

If ecological modeling is to become a standard tool for risk assessments of pesticides, all stakeholders involved need to understand what models are and how they are developed. It is important to realize that models by definition ignore many, if not most, aspects of real systems in order to identify key factors of the system s internal organization. Models are based on assumptions that are implemented, tested, and revised. Model development is iterative and ends when certain acceptance criteria are fulfilled. To assess or evaluate a model, we need to know its purpose. 

The aim of our stock taking was to prove that these key issues need to be addressed explicitly and in a systematic, standardized way. There needs to be a clearly defined set of criteria by which models can be assessed so that all stakeholders involved in pesticide registration gradually build up confidence in ecological models as a tool for decision making. In this way, we could eventually start utilizing the potential of ecological models to overcome the inherent limitations of risk assessments that focus on effects at the level of individuals (Chapter 2). 

Information on exposure levels is fundamental for the assessment and management of health risks related to occupational and environmental exposure to pesticides. Biological monitoring is a primary tool for exposure evaluation,... 

The use of uncertainty analysis and probabilistic methods requires systematic and detailed formulation of the assessment problem. To facilitate this, a) risk assessors and risk managers should be given training in problem formulation, b) tools to assist appropriate problem formulation should be developed, and c) efforts should be made to develop generic problem formulations (including assessment scenarios, conceptual models, and standard datasets), which can be used as a starting point for assessments of particular pesticides. 

The proposed tiers are not obligatory but contain extrapolation tools that can be used differently in a number of situations and, in some cases, regulatory protocols, in which certain combinations of extrapolation methods are prescribed as methods that must be used for the assessment, such as in the formal registration of pesticides. The proposed tiered system is based on a scientific classification of the available extrapolation method types. With ideal data and concepts for extrapolation, this scheme may be expected to yield reduced degrees of overestimation of risk when moving up the tiers from Tier-0 to Tier-4 (i.e., risks are more precisely estimated in the higher tiers). 

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