07.04.24 Flashcards
What are the two strategies practiced for the preservation of a variety of living species globally
- In-situ conservation
- Ex-situ conservation
- process of protecting an endangered plant or animal species in its natural habitat
- process of collecting specimens or data in the wild or on-site
in-situ
- relocation of endangered or rare species from their natural habitats to protected areas equipped for their protection and preservation
- collection of samples in the wild for its analysis in the laboratory
ex-situ
What is proper sample preservation and handling for
accurate materials analyses
if samples are not cared for properly, important information may be..
- destroyed
- adulterated
- obscured
where does soil sampling depend
- depth of desired sample
- type of sample required
- soil type
what are the type of sample required
- disturbed
- undisturbed
This type of sample is collected in a way that disrupts the natural structure and arrangement of the soil layers
disturbed sample
This type of sample is collected in a way that preserves the natural structure and layering of the soil as much as possible.
undisturbed sample
may be easily sampled using a spade, trowel, and scoop
near-surface soils
may be performed using a hand auger, continuous flight auger, a trier, a split-spoon, or, if required, a backhoe
sampling at greater depths
preservation method of soil sample not generally recommended
chemical preservation
how to minimize potential reaction in soil sample
cooled and protected from sunlight
Primary potential problems associated with soil sampling
- cross contamination
- improper soil collection
- can be eliminated or minimized through the use of dedicated sampling equipment
- if not possible or practical, then decontamination of sampling equipment is necessary
cross contamination
can involve using contaminated equipment, disturbance of the matrix resulting in compaction of the sample, or inadequate homogenization of the samples, resulting in variable, non-representative results
improper sample collection
refers to the maximum amount of time a sample can be stored before analysis without compromising the accuracy of the results
Hold time
common sampling methods for laboratory analysis
- grab sample
- composite sample
a discrete, individual sample taken within a short period of time (usually less than 15 min.)
grab sample
- sample comprised of a series of individual aliquots that have been combined to reflect mean analyte concentrations of the discharge during the sampleing period
- can be developed based on time or flow rate or depth
composite sample
