Appendix 2A–B. Descriptions of methods for harbor-site sampling and mercury sampling.

Regular samples

• Kemmerer sampler
• Fill pickle jar with 9 liters to make composite sample.
• Field clean equipment between sampling locations.
• Weighted sampler
• Fill three baked 1-liter amber glass bottles for:
• Dissolved organic carbon (DOC) and total particulate carbon and nitrogen analysis
• Pesticides analysis
• Wastewater analysis
• Field measurements (dissolved oxygen (DO), temperature, pH, and specific conductance)
• Three measurements—one measurement at each of three depths

QA/QC samples: These samples are collected in association with regularly collected samples and are also done at a specified frequency.

• Blanks: A blank is run after a regular sample is collected and equipment has been cleaned.
• Samples regularly collected with kemmerer sampler
• Fill sampler with universal blank water then dump into pickle jar, as one would a sample
• Samples regularly collected with weighted sampler
• Fill 1-L glass bottles with universal blank water, cap
• No field measurements are made on universal blank water
• Sample time recorded as 1 minute before the regular sample’s time
• Replicates:
• Kemmerer sampler
• Collect replicate samples immediately after the original sample has been collected, in the same manner
• Weighted sampler
• Collect replicate samples immediately after the regular sample has been collected, in the same manner
• No additional field measurements are needed; use the ones from the regular sample
• Sample time is recorded as 1 minute after the regular sample’s time

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Whole-water samples were collected whenever possible from the centroid of flow by field personnel wearing arm-length gloves and submersing a 1-L PETG (glycol-modified polyethylene terephthalate) bottle. The filled bottle was hermetically sealed in a re-sealable clear plastic bag and immediately placed in a cooler for transport to the USGS Wisconsin Mercury Research Laboratory in Middleton, Wis. Once at the lab, the water samples were filtered to separate the dissolved and particulate associated fractions of methylmercury and total mercury. Sample filtration was done by use of an acid-cleaned, plastic filtration dome, baked (at 500ºC); quartz fiber filters (QFFs); a vacuum pump, and a Teflon sample tower. In this procedure, the sample is exposed to ambient air for a few minutes and only contacts Teflon surfaces that have been rigorously cleaned in hot acid, thoroughly rinsed with deionized water, and then double-bagged until use. Filtered water samples for total mercury and methylmercury analysis were preserved by adding concentrated HCl to 1 percent by volume. Particulates retained on the QFFs during filtration were immediately placed in Teflon petri dishes, sealed in clear plastic bags, and kept frozen until analysis.

A brief description of the analytical procedures for total mercury and methylmercury water and suspended particulates is given here but a complete description can be found in Olson and DeWild (1999), Dewild and others (2004), and Olund and others (2004). Total mercury and methylmercury determinations were done at the USGS Wisconsin Mercury Research Laboratory, a facility specifically designed and dedicated for low-level speciation analysis of environmental samples for mercury. Total mercury was determined by cold vapor atomic fluorescence spectroscopy (CVAFS) following oxidation with BrCl at 50ºC, reduction by SnCl², and purge and trap of the evolved Hg0 onto gold-coated glass bead columns. The analytical procedure for methylmercury is a two-step process involving distillation of the sample to separate the methylmercury from potential matrix-interference effects of dissolved organic carbon (DOC), followed by aqueous phase ethylation and quantification using gas chromatography and CVAFS. Ancillary chemical data to assist in the interpretation of the results were determined by the following methods: pH was measured in the field with a calibrated probe, sulfate by ion chromatography, and DOC by a carbon analyzer that employs acidification and persulfate/UV oxidation.

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continue to Appendix 3. Water-quality properties and constituents, reporting levels, and analyzing laboratories.