Safety - Field Sampling: Principles and Practices in Environmental Analysis - page 102

water safety precautions, such as life preservers, must also be followed.
4.9. CONTAMINATION TYPES AND CONCENTRATIONS
Two other aspects of safety are the contaminant concentration and type. We are all
exposed to radiation and arsenic every day but we do not feel it and there are not any ill
effects from them as long as they are at natural or background levels. There are some
toxic chemicals that are an essential part of the diet. Selenium is toxic and yet it is
essential for good health. Boron is an essential nutrient for plants and yet if levels are
even a little too high it is toxic to them. (See also Chapter 9.)
When concentrations above natural or background levels are likely to be encountered
in the field safety precautions are extremely important. On a site heavily contaminated
with VOCs it is critically important to eliminate all sources of ignition, such as matches
and cigarettes. In fields contaminated with heavy metals or selenium, inhalation of dust is
of concern. Fields contaminated with radioactive waste require special protective clothing
and radiation monitoring badges. In addition to knowing the type of toxic material likely
to be encountered it is thus also important to know its likely concentration.
Many types of contamination are designated toxic, but that does not mean that they are
all toxic in the same way. Gases are toxic by inhalation; liquids by inhaling fumes,
drinking, or getting on skin; and solids by contact, eating, or reaction to form toxic
substances. Because of these differences the way they are treated and the precautions
taken need to be appropriate to the material being handled. It is thus important to consult
MSDS sheets dealing with the particular toxic material present or being handled.
4.10. OFF-FIELD PROTECTION
Sample containers need to be clean on the outside before they exit a contaminated site. If
glass containers are used they should be sealed in a plastic bag and wrapped in protective
material, such as bubble wrap. No portion of the sample should escape during storage or
transportation to the analytical laboratory. Also, as noted above, the proper signage needs
to be affixed to containers of samples so that in the case of a spill persons handling the
samples will know how to respond appropriately.
4.11. THE CHEMICAL HYGIENE PLAN
The CHP will be a document that outlines appropriate safety procedures for the field
being sampled. It explains how to handle various types of chemicals and what to do in
case of spills and accidental exposure to dangerous materials. All personnel need to know
where the CHP is and how to use it. Some topics commonly covered in a CHP are given
in Table 4.6. Details of the development of a CHP can be found on the Internet, along
with a sample plan. There are also various publications describing CHP plans [3, 12, 13].