Low Level Mercury Analysis

Method Overview

Method 1631E provides measurement of mercury at previously unachievable, ultra-trace levels in water matrices, in support of state NPDES permit limits, TMDL measurements, and the Great Lakes Initiative. Mercury is analyzed using Cold-Vapor Atomic Fluorescence Spectrometry. Ultra-clean sampling techniques (Method 1669) along with laboratory analysis under clean room conditions are used to ensure the lowest achievable detection limits and to avoid common causes of sample contamination.

Method Detection Limits

Detection limits achieved by Method 1631E may vary according to the sample matrix and effectiveness of the sampling technique. Current method detection and reporting limits are:

• Matrix                                   Detection Limit                      Reporting Limit
• Water Samples                             0.197 ng/L                            0.500 ng/L

Method Specifications

• Preservation Holding Times:  28 days to preservation
• Analysis Holding Times:        90 days from collection
• Method Turnaround (TAT):    10 business days
• Field QAQC:                        One field blank per sample point (<0.500 ng/L

                                               or 1/5 sample conc.)