RADAR

RADAR (Risk Assessment tool to evaluate exposure Duration And Recovery) was developed by Waterborne for the Ecological Committee on FIFRA Risk Assessment Methods (ECOFRAM) to evaluate time-series concentration data for exposure characterization. As described below, several types of analyses are performed.

To obtain a copy of the model, please go to the model download page.

Probability Analysis on Extreme Value Series

The extreme value series consists of the largest observation in a given time interval. Annual series and 30-day series are recommended by ECOFRAM for a Tier 2 analysis. Observations include peak concentration and 24-hour, 48-hour, 96-hour, 21-day, 60-day, and 90- RADAR day durations. A user-defined series may also be evaluated for extended Tier 2 analysis or Tier 3 applications. A user-defined series may represent a sensitive life stage or the period of species and habitat co-occurrence based on migratory patterns. Probabilities are calculated using the Weibull probability distribution.

Catalog and Characterization of Exposure Events

Events are defined by concentration exceeding a threshold value. Event characterization includes the event duration, peak concentration, arithmetic mean concentration, geometric mean concentration, standard deviation of concentration within the event, peak concentration to average concentration ratio, number of inflections within the event, and dose commitment (the time integral of magnitude above threshold for event). The event duration is the elapsed time until the concentration drops below the threshold.

Period of Record Summaries

Summary statistics are provided for both the complete data record and for a user-defined season throughout the period. Statistical information includes the minimum, maximum, and average value of various event attributes. The program also summarizes the percent of time throughout the analysis period that concentrations exceed the threshold concentration.

Event Tally Based on User-defined Sensors or Triggers

This output provides the number of events that occurred within each year or seasonal period within each year. Events can be defined by threshold.

References

Hendley, P., J. Giddings. (1999) Draft report of the Aquatic Workgroups of ECOFRAM (Ecological Committee on FIFRA Risk Assessment). US Environmental Protection Agency, Pesticides: Environmental Effects, Initiative to Revise the Ecological Assessment Process for Pesticides.

Williams, W.M., P. Singh, KH. Reinert, and J.M. Giddings (1999). RADAR: Risk Assessment Tool for Aquatic Exposure Characterization. Poster session, 20th Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, November 1999.

Giddings J. M., Anderson T. A., Hall L.W., Hosmer A. J., Kendall R. J., Richards R. P., Solomon K. R., Williams W. M., 2005. Aquatic Ecological Risk Assessment of Atrazine, A Tiered Probabilistic Approach. SETAC Press, 2005.

Reinert, K.H.; J.M. Giddings, and L. Judd, 2002. Effects Analysis of Time-Varying or Repeated Exposures in Aquatic Ecological Risk Assessment of Agrochemicals. Environmental Toxicology and Chemistry, Volume 21, Issue 9.