Method 29 Hg Only
Determination of Mercury Emissions from Stationary Sources
This method is for the collection and analysis of mercury (Hg) emissions from stationary sources. Hg emissions can be measured, alternatively, using EPA Method 101A of Appendix B, 40 CFR Part 61. This method is considered by most as equivalent to the SW-846 0060 / 7471 series of methods. This method also allows for the determination of particulates using Method 5 procedures from the filter and probe rinses if required. The method requires that each mercury fraction generated from the sampling train (there are 5) be analyzed separately and in duplicate using cold vapor atomic asorption (CVAA) following SW-846 Method 7471A.
Samples are collected isokinetically using a Method 29 train (similar to a Method 5 train) consisting of a quartz filter containing no organic binders and a series of impingers. The 1st and 2nd impingers are filled with 100mL of a HNO3/ H2O2 solution. The 3rd impinger is left empty. The 4th and 5th impingers are filled with 100mL of acidified KMnO4. The 6th impinger is filled with 200-300g of silica gel.
It is important that no metal be used in the probe, probe liner, filter support, or in the collection brushes used in sample recovery. Metal parts could serve as a source of contamination of the sample. The method also calls for the solution of KMnO4 to be prepped daily. It is also important to note safety precautions to be used when shipping the KMnO4. There must be a way for the glass container to vent as KMnO4 reacts with acid present in the solution to form a gas and there must be a way for the container to vent, otherwise, it becomes an explosion hazard.
After collection, the contents of all impingers are weighed to later assist with the determination of stack moisture. The filter is folded such that the particulate is on the inside on the filter and placed in a petri dish. In all the sample collection procedures, it is important to use 100mL of rinsing solution as specified in the method so that the blank correction procedures will be correct. An acetone rinse of the probe, liner, and front half of the filter holder (if particulates are determined) is collected in a separate container. This rinse is not collected if particulates are not needed. The probe, liner and front half of the filter holder is rinsed with HNO3 and collected in a separate container. The contents of the HNO3/H202 impingers and associated HNO3 rinses of the impingers can be combined into one container or multiple containers if needed for volume. HNO3 is used to rinse the empty impinger and is collected in a separate container. Another container holds the contents of the KMnO4 impingers which are combined with the KMnO4 rinse of the impingers and collecting glassware and water rinse of the impingers and connecting glassware. The impingers are then washed with exactly 25mL of 8N HCl and put into a separate container holding 200mL of water.
The filter, acetone rinse (if collected), and probe rinse are all digested separately with HNO3 and concentrated HF and then combined for analysis. This sample represents the front half section of the sampling train. The HNO3/H202 impingers and rinses are digested with HNO3 and concentrated HF and then analyzed. The three sample fractions generated from the KMnO4 impingers are all analyzed separately.
(EPA 40CFR Part 60 Appendix A)