Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles (Final Report)
The Ecological Risk Assessment Support Center (ERASC) is announcing the release of the final report entitled, Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles.
The report evaluates approaches for estimating the probability of ingestion by birds of contaminated particles such as pesticide granules or lead particles (i.e. shot or bullet fragments). In addition, it presents an approach for using this information to estimate the risk of mortality to birds from ingestion of lead particles.
An important route of chemical exposure in many ecological risk assessments is the ingestion of chemicals on or in sediments, soil and small gravel (i.e., grit). Several approaches have been developed to address this route of exposure in risk assessments. The particular focus for this white paper is to evaluate approaches available for estimating the risk to birds from ingestion of lead shot or other lead fragments (hereafter referred to as lead particles). There are many similarities between lead particle ingestion and the ingestion of pesticide granules as grit or food items. More specifically, the paper focuses on two primary issues affecting avian exposure to lead—the rate of ingestion of lead particles by birds and the length of time lead particles are retained and eroded in avian gizzards to release a dose of lead to target organs. The paper discusses soil and grit ingestion by birds, reviews several published approaches for estimating the rate of ingestion of lead particles or pesticide granules, and examines the important sources of uncertainty in parameter estimates for approaches to estimating exposure to lead particles. It recommends an approach for improving the estimation of lead particle exposure to birds in ecological risk assessments. This paper does not comprehensively review the toxicity of lead in birds, but does demonstrate an approach for estimating the risk of mortality from ingesting lead particles.
|Oct 2007||An Internal Review Draft was completed.|
|Dec 2009||Internal review was completed and comments were addressed to produce the report, Risk to Birds from Ingestion of Contaminated Grit Particles (a draft that was externally peer reviewed).|
|Mar 2011||EPA published the final report incorporating external peer review comments.|