Figure 2.  Relationships between EMAP sediment tables

The diagram below shows the sediment data tables and their relationships with each other.  The data in all the tables can be linked using the station ID field.   (The toxicity table is shown with a dotted border because it has not been incorporated into this USGS database.)  EPA maintains similar relational tables for biological and water quality data, and these tables are also related to these sediment tables via the station ID ("sta_name").  See Table 2 for example data from the chemistry table.

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