Background Levels

{
  "id": "MLC-T-ENV-002632",
  "term": "Background Levels",
  "field": "Environment",
  "definition": "1. Two types of background levels may exist for chemical substances: (a) Naturally occurring levels: Ambient concentrations of substances present in the environment, without human influence; (b) Anthropogenic levels: Concentrations of substances present in the environment due to human-made, non-site sources (e.g., automobiles, industries).\n\n2. Levels representing the chemical, physical, and biological conditions that would result from natural geomorphological processes such as weathering or dissolution.\n\n3. The concentration of a chemical already present in an environmental medium due to sources other than those under study. Two types of background levels may exist for chemical substances: (a) Naturally occurring levels of substances present in the environment, and (b) Anthropogenic concentrations of substances present in the environment due to human associated activities (e.g., automobiles, industries).\n\n4. Two types of background levels may exist for chemical substances: 1) Naturally occurring levels: ambient concentrations of substances present in the environment, without human influence. 2) Anthropogenic levels: concentrations of substances present in the environment due to human-made, non-site sources (e.g., automobiles, industries).\n\n5. The concentration of a substance in an environmental media (air, water, or soil) that occurs naturally or is not the result of human activities. In exposure assessment the concentration of a substance in a defined control area, during a fixed period of time before, during, or after a data-gathering operation.\n\n6. An average or expected amount of a substance or radioactive material in a specific environment, or typical amounts of substances that occur naturally in an environment.",
  "subject": "Health and safety",
  "references": [
    "Integrated Risk Information System (IRIS) Glossary; IRIS, 1999: Glossary of IRIS Terms",
    "Sediment Total Maximum Daily Loads (TMDLs) Glossary",
    "Improving Air Quality in Your Community Glossary; EPA 2004",
    "EPA 2003",
    "EPA 2005b",
    "ATSDR 2004"
  ],
  "url": "https://mlchart.com/terminology/environment/background-levels/"
}