NEMI Method Summary

Method Summary Information

Method Number: 180.1 Media: WATER
Revision: Revision 2.0, August 1993
Method Source: U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]
Analytes in this method
Subcategory: INORGANIC
Official Name: Turbidity (Nephelometric)
Descriptive Name Turbidity by Turbidimeter
Source Info: U.S.EPA National Exposure Research Laboratory (NERL)
Microbiological and Chemical Exposure Assessment Research Division (MCEARD)
[formerly the Environmental Monitoring Systems Laboratory (EMSL), Cincinnati, OH]
26 West Martin Luther King Drive
Cincinnati, Ohio 45268-0001
Fax: 513-569-7757
email: DWmethods.help@epa.gov
Citation: Methods for the Determination of Inorganic Substances in Environmental Samples (EPA/600/R-93/100)
29196 Byte file
Brief Method
Summary:
 The method is based upon a comparison of the intensity of light scattered by the sample under defined conditions with the intensity of light scattered by a standard reference suspension. The higher the intensity of scattered light, the higher the turbidity. Readings, in NTU's, are made in a nephelometer designed according to specifications outlined in the method. A standard suspension (i.e., formazin, AMCO-AEPA-1, or Hach Stablcal) is used to calibrate the instrument.
Scope And
Application:
 This method is applicable to drinking, surface, and saline waters in the range of turbidity from 0 to 40 nephelometric turbidity units (NTU). Higher values may be obtained with dilution of the sample.
Applicable
Conc Range:
 0 - 40 NTU
Interferences: The presence of floating debris and coarse sediments which settle out rapidly will give low readings. Finely divided air bubbles will affect the results in a positive manner. The presence of true color, that is the color of water which is due to dissolved substances which absorb light, will cause turbidities to be low, although this effect is generally not significant with finished waters.
QC Requirements: None.
Sample Handling: Preservation of the sample is not practical; analysis should begin as soon as possible. Refrigeration or icing to 4oC, to minimize microbiological decomposition of solids, is recommended.
Max Holding Time:
 48 hours (MCAWW, Table I)
Sample Prep Met None.
Relative Cost: Less than $50
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