How many SOC non-detects does it take to be meaningful?

摘要

Changes are needed in the way drinking water compliance monitoring is conducted. A greater focusrnis needed on constituents that have public health significance. Changes are needed to allowrnregulatory flexibility so that knowledge from past monitoring can be applied and increase thernpotential that monitoring might have a real public health impact. This should include the ability torneliminate testing requirements for parameters that are rarely detected in drinking water.rnCompliance monitoring data were reviewed for Synthetic Organic Compounds (SOCs) inrnPennsylvania and compared with national trends. Details are provided on the detection of specificrncompounds, including: DEHP, atrazine, EDB, simazine, glyphosate, dioxin, and PCBs.rnRecent data from Pennsylvania are significant because in 2011, previously issued monitoringrnwaivers were eliminated. In addition, results from Pennsylvania were not included in EPA’srnmandated six-year review of drinking water data. In the absence of newly issued monitoringrnwaivers, water systems were required to conduct initial quarterly monitoring in 2011 for manyrnSOCs that were probably not previously tested in their system. Major implications of the newrnregulations included a dramatic increase in monitoring/reporting violations and the cost ofrnimplementing the rules.rnA review of data from Pennsylvania’s Drinking Water Reporting System indicated that all of the 30rnregulated SOCs had low rates of occurrence (even lower than national rates). The number ofrnPennsylvania samples with a result over a Maximum Contaminant Level was extremely low (16rnover the past 11 years).rnRecommendations to improve the process and more effectively use the finite resources of waterrnsystems and regulatory agencies include: revise regulations and Standard Monitoring Frameworkrnas part of the next SDWA-mandated 6-year review process; revise or eliminate monitoringrnrequirements for parameters with very low rates of occurrence; encourage the use of EPA HealthrnAdvisories to replace or supplement regulations.