Non-Detects

{
  "id": "MLC-T-ENV-018835",
  "term": "Non-Detects",
  "field": "Environment",
  "definition": "Pollutants that are measured at concentrations below the sample detection limit concentration. The Advanced Search provides users three options for calculating pollutant loads for concentrations reported “not detected,” setting all concentrations reported “not detected” to zero, to ½ the detection limit, or to the detection limit. Section 3.1.3 of the Technical Users Background Document for the Water Pollutant Loading Tool (https://echo.epa.gov/trends/loading-tool/resources/technical-support-document) describes how the Loading Tool calculates pollutant loads for concentrations reported “not detected”. Search Considerations:The Loading Tool identifies pollutant measurements that are \"not detected\" using data qualifiers in ICIS-NPDES. If these qualifiers are missing due to a data-entry error, then the Loading Tool will not identify the measurement as a non-detect. These data are from ICIS-NPDES.",
  "subject": "Enforcement and compliance",
  "references": [
    "Glossary of Frequent Terms in the Loading Tool"
  ],
  "url": "https://mlchart.com/terminology/environment/non-detects/"
}