Traps, Mistakes, and Errors - Field Sampling: Principles and Practices in Environmental Analysis - page 281

TABLE 11.2 Soil Analysis Results for a Field in Central Ohio

cmol c /kg

1:1 kg/ha

Soil sample number pH CEC Ca Mg P K

WC-15a 5.6 8 1,200 230 15 200

WC-15b 6.1 10 1,100 340 22 195

WC-15c 7.4 10 1,500 550 10 156

WC-15d 5.9 9 1,000 320 23 250

WC-15e 6.2 9 1,100 360 25 245

lakes, and other bodies of water or onto uncontaminated land. It is also possible to have
water moving underground for some distance only to emerge aboveground at some other
locality. All of the area in which the water is moving both below- and aboveground is
important to sample and monitor. In addition to water carrying contaminants out of an
area it can also carry contaminants into an area. Recognizing the potential for movement
of contaminates out of and into an area will greatly simplify sampling.

11.3. KNOWING WHAT IS OR IS LIKELY TO BE PRESENT

For both safety and sampling it is essential to have some idea of the type and amount of
contamination that is known or suspected to be present. The type and amount of
protective equipment and clothing needed by sampling personnel will be dictated by this
information. Relatively innocuous contaminants that do not produce hazardous fumes and
are not toxic will require minimal safety equipment and precautions. On the other hand,
high levels of contamination and contamination with highly toxic materials will require
the maximum in safety equipment and precautions.
The type of sampler and sample container used will be determined by the type of
contaminant thought to be present. Samples thought to contain volatile organic
compounds (VOCs) need to be sampled and placed in sealed containers without
headspace. * This is necessary to prevent the loss of VOCs before the analysis can be
completed. On the other hand, soil to be analyzed for metals need not be stored in
containers that are airtight. However, in this case they must be kept away from metal
contamination, which might occur if they were stored in metal sample containers. Also,
samples stored for metal analysis may lose other contaminants (e.g., VOCs), and thus
borrowing a portion of this sample for some other analysis is not possible.

* Headspace is the space (air space) between the sample and the top of the container closure.