Contaminants in the Mississippi River
U.S. GEOLOGICAL SURVEY CIRCULAR 1133
Reston, Virginia, 1995

### CONVERSION FACTORS AND ABBREVIATED WATER-QUALITY UNITS

```

Multiply                           By                   To obtain

meter (m)             3.281                   foot
kilometer (km)            0.6214                  mile
square kilometer (km2)           0.3861                  square mile
cubic kilometer (km3)           0.2399                  cubic mile
centimeter (cm)            0.3937                  inch
millimeter (mm)            0.03937                 inch
micrometer (µm)            0.00003937              inch
liter (L)             1.057                   quart
milliliter (mL)            0.03381                 fluid ounce
kilogram (kg)            2.205                   pound, avoirdupois
metric ton          2205                       pound, avoirdupois
cubic meter per second (m3/s)          35.31                    cubic foot per second
kilogram per square kilometer (kg/km2)           0.008924                pounds per acre

Concentration unit                                          Equals

milligram per gram (mg/g)                                      part per thousand
milligram per kilogram (mg/kg)                                     part per million
microgram per gram (µg/g)                                      part per million
nanogram per gram (ng/g)                                      part per billion (109)

Concentration unit                                          Approximately* equals

gram per cubic meter (g/m3)                                      part per million
milligram per liter (mg/L)                                      part per million
microgram per liter (µg/L)                                      part per billion (109)
nanogram per liter (ng/L)                                      part per trillion (1012)

*At the concentrations encountered in this study, and considering the detection limits of the
analytical methods employed, these units can be considered equal in the context of this report.

Degree Celsius (°C) may be converted to degree Fahrenheit (°F) by using the
following equation:

°F=9/5 (°C)+ 32.

Sea level:  In this report "sea level" refers to the
National Geodetic Vertical Datum of 1929 (NGVD of 1929)--a geodetic
datum derived from a general adjustment of the first-order level nets
of both the United States and Canada, formerly called Sea Level Datum
of 1929.
```