Measurements of field parameters made in discrete or nonpumped samples are more vulnerable to bias from changes in temperature, pressure, turbidity, and concentrations of dissolved gases than measurements using a downhole or flowthrough-chamber system. Subsamples can be used for conductivity, pH, and alkalinity. Subsamples must not be used for reported measurements of temperature, dissolved oxygen, Eh, or turbidity. Figure 6.0-5 shows the steps for measurement of field parameters on a bailed sample. If collecting a sample with a bailer, use one with a double check valve.
Field rinse the sampler with sample water before using.
To shield the sample from atmospheric contamination, make measurements in a collection chamber or in a glove box filled with inert gas. Indicate on field forms the sampling and measurement procedures used.