Water Chemistry Field Sampling
54
reanalysis, if necessary), wide-mouth HDPE or LDPE bottles. For some studies,
it may be possible to use smaller bottles; some studies collect 2 L of water, but
this weighs about 4 pounds (1.8 kg). This can be an important constraint on
sampling of multiple remote sites.
Note that if water samples are to be collected for analysis of Hg concentrations, sample bottles will need to be Teflon or glass (with Teflon-lined caps),
and special bottle cleaning procedures will need to be followed, including prolonged heating in an acid solution. Check with the analytical laboratory for
specific requirements.
Preprinted labels with prompts for all required information associated
with the sample should be affixed to each sample bottle as part of the bottle
preparation. At a minimum, this information should include (1) collection date
and time, (2) site identification (lake or stream) (inlet/outlet/deep), (3) name
of the person who collected the sample (first initial and complete last name),
and (4) sample ID/bar code. The field crew must take precautions to ensure
that no bottle mouth is contaminated with leaking refrigerant, tap water, dirt,
handling contact, or other foreign substance. One reasonable precaution is to
package each processed bottle individually in a zipper-lock-type plastic bag.
Refrigerant should be in double zipper-lock bags. This precaution is especially
important if the laboratory analysis indicates that sample contamination has
been an issue in the past.
The following steps need to be completed before going to the field:
• Obtain the necessary sample bottles and (if required) syringes for
each site to be sampled. Depending on the intended laboratory analyses and sample replication requirements, this can range from one to
several bottles and syringes per site. Preprocessed bottles, often filled
with DIW, with a preprinted or blank label tape affixed, should be provided by the analytical laboratory. It is a good idea to carry a few extra
bottles beyond those needed for the intended sampling.
• Field studies often, but not always, include some sample replication
(often 5% to 10% of samples) for QA purposes. Replication is generally
desired to assess the repeatability of the sampling procedure, sample
holding and treatment, and laboratory analysis. The amount of replication will be dependent on the sampling design and the QA/QC program. Some studies replicate all samples. This should be done in areas
where access to the site is difficult and travel to the site is the biggest
expense involved in the sample collection and analysis.
• Obtain ice blocks or frozen refrigerant. Ice blocks generally work better for shipping samples to the lab unless a large number of refreezable packs are used. If using refrigerant, be sure that it has been in the
freezer at least 2 days prior to the day of sampling. If using block ice, it
54
reanalysis, if necessary), wide-mouth HDPE or LDPE bottles. For some studies,
it may be possible to use smaller bottles; some studies collect 2 L of water, but
this weighs about 4 pounds (1.8 kg). This can be an important constraint on
sampling of multiple remote sites.
Note that if water samples are to be collected for analysis of Hg concentrations, sample bottles will need to be Teflon or glass (with Teflon-lined caps),
and special bottle cleaning procedures will need to be followed, including prolonged heating in an acid solution. Check with the analytical laboratory for
specific requirements.
Preprinted labels with prompts for all required information associated
with the sample should be affixed to each sample bottle as part of the bottle
preparation. At a minimum, this information should include (1) collection date
and time, (2) site identification (lake or stream) (inlet/outlet/deep), (3) name
of the person who collected the sample (first initial and complete last name),
and (4) sample ID/bar code. The field crew must take precautions to ensure
that no bottle mouth is contaminated with leaking refrigerant, tap water, dirt,
handling contact, or other foreign substance. One reasonable precaution is to
package each processed bottle individually in a zipper-lock-type plastic bag.
Refrigerant should be in double zipper-lock bags. This precaution is especially
important if the laboratory analysis indicates that sample contamination has
been an issue in the past.
The following steps need to be completed before going to the field:
• Obtain the necessary sample bottles and (if required) syringes for
each site to be sampled. Depending on the intended laboratory analyses and sample replication requirements, this can range from one to
several bottles and syringes per site. Preprocessed bottles, often filled
with DIW, with a preprinted or blank label tape affixed, should be provided by the analytical laboratory. It is a good idea to carry a few extra
bottles beyond those needed for the intended sampling.
• Field studies often, but not always, include some sample replication
(often 5% to 10% of samples) for QA purposes. Replication is generally
desired to assess the repeatability of the sampling procedure, sample
holding and treatment, and laboratory analysis. The amount of replication will be dependent on the sampling design and the QA/QC program. Some studies replicate all samples. This should be done in areas
where access to the site is difficult and travel to the site is the biggest
expense involved in the sample collection and analysis.
• Obtain ice blocks or frozen refrigerant. Ice blocks generally work better for shipping samples to the lab unless a large number of refreezable packs are used. If using refrigerant, be sure that it has been in the
freezer at least 2 days prior to the day of sampling. If using block ice, it