Effects range low and effects range median

In <a href="/facts/Environmental_toxicology/HNaAP7tb">environmental toxicology</a>, effects range low (ERL) and effects range median (ERM) are measures of <a href="/facts/Toxicity/qa96rs60">toxicity</a> in marine <a href="/facts/Sediment/zsIH1A6U">sediment</a>. They are used by public agencies in the United States in formulating guidelines in assessing toxicity hazards, in particular from <a href="/facts/Trace_metal/tDXmwLAs">trace metals</a> or organic contaminants.
The ERL and ERM measures are expressed as specific chemical concentrations of a toxic substance in sediment. The ERL indicates the <a href="/facts/Concentration/wqBmz5od">concentration</a> below which toxic effects are scarcely observed or predicted: the ERM indicates that above which effects are generally or always observed. They are derived from biological toxicity <a href="/facts/Assay/fPUYjx1I">assays</a> and synoptic sampling.
The numerical values are incorporated in sediment quality guidelines (SQGs) that were developed by Long and Morgan for the <a href="/facts/National_Oceanic_and_Atmospheric_Administration/IvcuqNJg">National Oceanic and Atmospheric Administration</a> (NOAA) National Status & Trends program as informal tools to evaluate whether a concentration of a contaminant in sediment might have toxicological effects. These guidelines are used for screening sediments for trace metals and organic contaminants. They are not <a href="/facts/Regulatory/eFR0l2x9">regulatory</a> criteria in any way and are not intended to be used as such.

Effects range low and effects range median open-in-new

Effects range low and effects range median