Dense Non-Aqueous Phase Liquid

{
  "id": "MLC-T-ENV-007631",
  "term": "Dense Non-Aqueous Phase Liquid",
  "field": "Environment",
  "definition": "1. A non-aqueous phase liquid (NAPL) with a specific gravity greater than 1.0. Because the specific gravity of water is equal to 1.0, DNAPLs sink through the water column until they encounter a confining layer. DNAPLs flow along the surface of the confining layer and can migrate in directions contrary to the hydraulic gradient. Because DNAPLs are found at the bottom of aquifers (rather than floating on the water table) typical monitoring wells will not indicate whether DNAPLs are present. DNAPLs are typically chlorinated hydrocarbon solvents or very heavy petroleum fractions and are, therefore, not usually of concern at petroleum UST sites.\n\n2. A liquid which consists of a solution of organic compounds (e.g., chlorinated hydrocarbons) and which is denser than water. DNAPLs sink through the water column until they reach the bottom of the aquifer where they form a separate layer. Unlike LNAPLs, DNAPLs flow down the slope of the aquifer bottom which is independent of the direction of hydraulic gradient.\n\n3. Non-aqueous phase liquids such as chlorinated hydrocarbon solvents or petroleum fractions with a specific gravity greater than 1.0 that sink through the water column until they reach a confining layer. Because they are at the bottom of aquifers instead of floating on the water table, typical monitoring wells do not indicate their presence.\n\n4. Liquid contaminants that are relatively insoluble and heavier than water; also known as \"sinkers\" because they will sink to the bottom of an aquifer, where they become especially difficult to detect and clean up.\n\n5. A DNAPL is one of a group of organic substances that are relatively insoluble in water and more dense than water. DNAPLs tend to sink vertically through sand and gravel aquifers to the underlying layer.",
  "abbreviation": "dnapl",
  "subject": "Land, waste and cleanup",
  "references": [
    "Underground Storage Tank Sites Guide Glossary; Underground Tank Glossary",
    "Leaking Underground Storage Tanks Sites Glossary",
    "RCRA Glossary of Terms; Terms of Environment",
    "Superfund for Students and Teachers Glossary",
    "USDA National Agricultural Library Thesaurus"
  ],
  "url": "https://mlchart.com/terminology/environment/dense-non-aqueous-phase-liquid/"
}