CPG Specimen Collection & Handling 2

Question 1

When placing rock core into a standard core box, how should the core be oriented?

Accepted Answer

Shallowest core at the top-left, read left to right like a book

Answer

Convention places the top of the hole at the upper-left and the core is read left to right, row by row, like text on a page.

Question 2

What is the primary purpose of a trip blank in a groundwater VOC sampling program?

Accepted Answer

To detect VOC contamination introduced during shipping and storage

Answer

Trip blanks are prepared in the lab with analyte-free water, travel unopened with the samples, and reveal contamination from transport and storage.

Question 3

Which sampler is designed to obtain relatively undisturbed samples of soft, cohesive clay for consolidation testing?

Accepted Answer

Thin-walled (Shelby) tube

Answer

Thin-walled Shelby tubes (ASTM D1587) have a low area ratio that minimizes disturbance in soft cohesive soils.

Question 4

Groundwater samples collected for dissolved metals analysis should typically be handled how in the field?

Accepted Answer

Filtered through a 0.45-micron filter and preserved with nitric acid to pH below 2

Answer

Dissolved metals are operationally defined by 0.45-µm filtration, followed by HNO3 preservation to keep metals in solution.

Question 5

Why should VOC soil samples be collected with a coring device such as an EnCore or Terra Core sampler rather than spooned into a jar?

Accepted Answer

To keep volatile loss to a minimum by limiting disturbance and headspace

Answer

EPA Method 5035 calls for low-disturbance coring and sealed containers or methanol preservation to prevent volatilization.

CPG - Certified Professional Geologist Practice Test