Vernier Water Depth Sampler User Manual

Water Sampler

Purpose:

For the collection of water samples at varying depths or distances away from a shoreline.

Contents:

One (1) Assembled Water Sampler
One (1) Cord (15 meter length)

Site Selection:

If you are serious about collecting data on water quality in your area, several collection sites
must be carefully chosen. The site should be accessible year round and under all weather
conditions. You must be able to return to these sites each time you test. Be sure to get the land
owner's permission to use the site. Keep the site clean.

A meaningful collection site will allow you to collect samples from an open stream, river, or
lake. Sites located in shallows, behind dams, or other relatively sheltered areas may not represent
the stream as a whole.

Once a site is chosen, place a marker at the site, and record its location in your notebook
along with a site number. When collecting data, always record your data along with the site
number.

Water Sampling:

Make sure the retrieving line is securely fastened to the eye bolt in the side of the
water sampler. The line should be neatly coiled and free from tangles and knots. Fasten the free

end of the line to some permanent fixture of the dock, bridge or boat you are on; this will prevent
the water sampler from being lost overboard if the free end of the line accidentally slips through
your hands. Some users have found that a Lobsterman’s Toggle (float) is sufficient to prevent loss
of the sampler. When tied to the free end, the toggle will float on the surface of salt water while
supporting the sampler. This has not been documented in fresh water.

Arm the water sampler by pulling both balls directly outward at the same time, then folding
them up over the top of the sampler body. Slip the two metal tubes together (one inside the other)
and align the holes that have been drilled through their sides. When these holes have been aligned,

# 15010

OPERATING INSTRUCTIONS

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insert the trigger pin through both metal tubes. You can now release the balls. Pull the trigger pin
out slightly until it extends 1 cm beyond the
side of the metal tube.

A sharp tug on the retrieving line is all
that is required to trigger and seal the water
sampler. If you try triggering the sampler out
of the water, be sure that no one is standing
near by because the closing action is very
quick and the trigger mechanism will swing
wildly. The sampler is designed to properly
trigger under water.

To obtain a sample from a desired
depth, mark the retrieving line by wrapping
tape around the cord at the desired distance
from the sampler body. Arm the sampler, and
slowly lower it over the side of the boat or
dock until the mark you've made is touching the water. If the sampler tends to float instead of
sink, drop the sampler from a small height into the water. The white balls must flood if the
sampler is to sink. To capture the sample, take a firm grip on the line then pull sharply upward.
A quick tug of only a few inches is preferable. Slowly pull the sampler back out of the water.

To use your water sample, hold the water sampler vertically and gently pull the top ball up
and to the side. Be careful not to agitate the water because this will introduce additional oxygen
into the sample and affect any measurements of dissolved oxygen that you may make. The sample
may be withdrawn by opening the pinch cock.

When the sampling is completed, rinse your equipment with fresh water then dry.

Caution: Do Not Store the Water Sampler in the Armed Position.

Applications:

Dissolved Oxygen and Biological Oxygen Demand (BOD):

Oxygen can get into the water by a variety of methods; diffusion through the water's
surface, aeration by waves breaking or rapids splashing over rocks or water falls, and
photosynthesis from aquatic plants. Three fourths of the earths oxygen is produced by oceanic
algae. Animals living in the water require oxygen to live. If there are too many microscopic
animals in the water then the oxygen supply will be depleted. For example, if the water contains a
large amount of biodegradable material, bacteria will try to reduce this material into simpler
forms. This process uses up large quantities of oxygen. The Biological Oxygen Demand (BOD) is
a measure of the amount of oxygen used by living organisms in the water. Testing for BOD shows
the long term effects of biodegradable wastes in a given area whereas oxygen content tests report
on the conditions at the moment the test was made.

Procedure:

© 2006 The Science Source · P.O. Box 727 · Waldoboro, Maine 04572 ·Tel. [phone]

e-mail us: [e-mail] visit our web site: www.thesciencesource.com

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