Environmental applications concentration units

The conversion between concentration units and the expression of the units themselves can be confusing. We will now review the typical concentration units used in various environmental media. Concentration in water is usually given as mass per unit volume or moles per unit volume. The conversion between them is a straightforward application of molecular weights. For example, we have 2.0 g/m of CO2 dissolved in water. The molecular weight of carbon dioxide is 44 g/mole. Then the concentration in moles/m is... 

In recent years, improper disposal of various waste materials has posed serious threats to surface and groundwater supplies and developed into a global scale soil and water pollution problem [1], Heavy metals account for much of the contamination found at hazardous waste sites in the United States, and have been detected in the soil and groundwater at approximately 65% of the U.S. Environmental Protection Agency Superfund sites [2], Dramatic increases in land application of agricultural and municipal biosolids have accentuated the problem. In spite of their beneficial contributions as nutrient sources and soil conditioners, these amendments, if not monitored, pose a considerable environmental risk because of their high heavy-metal concentrations [3],... 

US EPA, United States Environmental Protection Agency RfC, reference concentration OSHA, Occupational Safety and Health Administration NIOSH, National Institute for Occupational Safety and Health ACGIH, American Conference of Governmental Industrial Hygienists PEL, permissible exposure limit REL, recommended exposure limit TWA, time-weighted average IDLH, immediately dangerous to life or health TLV, threshold limit value NA, not applicable. 

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