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| Map and histogram showing concentration levels and locations of lead (Pb) samples in Boston Harbor that are currently in the database. High metal values are those greater than the ER-M (110 micrograms/gram), the concentration at which 50 percent of test sediments are found to have consistent adverse effects on biota. Low metal values are those less than ER-L (35 micrograms/gram) the concentration at which 10 percent of test sediments are found to have consistent adverse effects on biota. |
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