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Chapter 3
Laboratory Analyses
3.1 INTRODUCTION
Surface water samples collected in watersheds on forested lands with minimal recent influence from urban or agricultural development tend to have
low concentrations of nutrients. Because these watersheds are most commonly located in upland areas with rocky, infertile soils, their drainage
waters also tend to have low ionic strength. This means that most other dissolved constituents are also low in concentration. Analysis of water samples
having low concentrations of major constituents is challenging. Chemical
analysis of dissolved materials at low concentrations sometimes requires
modification of the standard methods used by the laboratory for routine
sample preparation and analysis. The laboratory selected for analyzing lownutrient, low-ionic strength surface water samples should not only be experienced with these types of samples but also should (1) analyze them on a
routine basis and (2) provide data with reporting limits sufficiently low for
project needs.
Studies of effects of atmospherically deposited constituents, including acid
precursors, nutrients, and toxic substances, entail collection of water samples
and laboratory analysis of a wide range of chemical parameters using a wide
range of instruments and analytical methods. It is beyond the scope of this
book to describe them. Nevertheless, there are a number of laboratory issues
common to most or all such investigations. These are the issues we focus on
in presenting this protocol. We outline important steps to be taken, or at
least considered, by the laboratory in conducting water quality studies. These
include elements of laboratory preparation prior to sample analysis and the
analyses themselves. In preparing to accept samples for processing, the laboratory must rely on developed procedures for bottle cleaning, sample processing,
and the preservation (as needed) and storage of samples in the laboratory. The
investigators must ensure that, to the extent possible, preprocessing holding
Chapter 3
Laboratory Analyses
3.1 INTRODUCTION
Surface water samples collected in watersheds on forested lands with minimal recent influence from urban or agricultural development tend to have
low concentrations of nutrients. Because these watersheds are most commonly located in upland areas with rocky, infertile soils, their drainage
waters also tend to have low ionic strength. This means that most other dissolved constituents are also low in concentration. Analysis of water samples
having low concentrations of major constituents is challenging. Chemical
analysis of dissolved materials at low concentrations sometimes requires
modification of the standard methods used by the laboratory for routine
sample preparation and analysis. The laboratory selected for analyzing lownutrient, low-ionic strength surface water samples should not only be experienced with these types of samples but also should (1) analyze them on a
routine basis and (2) provide data with reporting limits sufficiently low for
project needs.
Studies of effects of atmospherically deposited constituents, including acid
precursors, nutrients, and toxic substances, entail collection of water samples
and laboratory analysis of a wide range of chemical parameters using a wide
range of instruments and analytical methods. It is beyond the scope of this
book to describe them. Nevertheless, there are a number of laboratory issues
common to most or all such investigations. These are the issues we focus on
in presenting this protocol. We outline important steps to be taken, or at
least considered, by the laboratory in conducting water quality studies. These
include elements of laboratory preparation prior to sample analysis and the
analyses themselves. In preparing to accept samples for processing, the laboratory must rely on developed procedures for bottle cleaning, sample processing,
and the preservation (as needed) and storage of samples in the laboratory. The
investigators must ensure that, to the extent possible, preprocessing holding