SO461 Lab, Fall 2014
Wet Sieve and Pipette Sediment Analysis
- One member of the group should label and weigh 6 small
beakers. You must use the sensitive balances with the weighing enclosures
accurate to 0.0001 g,
because we will have very small quantities of sediment.
Use this data sheet.
- Sediment prep
Select a sample of about 25 g of sediment. Obvious shells
should be removed. This need be accurate only the nearest gram, and
insures an adequate sample size without inducing flocculation
Use the #230 sieve, with a pan below it
Use the fine brush and a squirt bottle of distilled water, and
wash the sediment through the sieve. You should have a small number of sand
grains on the sieve, and all the fines in a watery mixture in the pan.
Place the sand in a small beaker. You can wash the sieve, and
drain off any excess water from the beaker. This is sample #1.
Transfer the fines/water mix into a 1000 ml graduated cylinder.
Wash the pan clean.
Add 20 ml of 0.5% calgon solution to the graduated cylinder.
This prevents flocculation.
Fill the cylinder to the 1000 ml level
- Check the water temperature to determine the correct
time table to use.
- Use the stirrer to thoroughly mix the fines in the
- Start timing.
- At the indicated time (http://pubs.usgs.gov/of/of00-358/graphics/chapter1/c1tab2.htm),
and withdrawal depth, remove 20 ml of solution with a pipette. Place the
solution in one of the beakers.
- If the next time comes too soon, you can restir the
mixture and restart the clock. This should only be a problem for the 5F
- You should be able to take samples for 4,5,6,7
F samples. These will be samples
#2 to #5.
- Take a sample of 20 ml of the Calgon solution and place
it in a beaker. This is sample #6. This amount of Calgon
will be in each of the pipette samples.
- Dry the samples in the drying oven overnight.
Verify that you have 6 beakers, and they are labeled so that you can identify
them as belonging to your group and the sample.
- Reweigh the samples and compute the weight in each
class. Use this data sheet.
Equipment per group:
- 1 1000 ml plastic
- 1 large plastic funnel
- 1 stirrer
- 6 50 ml pyrex beakers
- 1 25 ml pipette
- 1 #230 sieve, with pan
- 1 camelís hair brush
- 1 Squeeze bottle
- 1 scoop for sediment
Equipment for class:
- Calgon solution
- 30% hydrogen peroxide solution (about 100
ml) for demonstration
- Drying oven
- One or more sensitive balances with the weighing
enclosures, accurate to 0.0001 gm. Those accurate to 0.01 gm are not
adequate for this lab.
The removal of organic matter may be necessary to achieve
complete dispersion of the clay and, in sediments with an elevated organic
content (>3%), to prevent the organics from being counted as part of the sample,
which would bias the grain-size distribution. The sample is placed in a 600-ml
beaker and a small volume (~10 ml) of 30% hydrogen peroxide is added. The sample
is stirred and, if necessary, water is added to slow the reaction down and
prevent bubbling over. More hydrogen peroxide is added until the dark color of
the organic matter has largely disappeared; then the sample is washed three
times with a NaOAc buffer of pH 5 and once with methanol to remove the remaining
released cations (Jackson, 1956).