Water 101 Sampling and Sondes
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Water 101Sampling and Sondes
Common Sample Types
Metals-in-Water
Routine Water Chemistry
Sediment Contaminants
Flow Measurement
Field Parameters
Presenter
Presentation Notes
The most common routine sampling types are field measurements, water chemistry, and instantaneous streamflow. However metals in water and sediment contaminants are often collected routinely at some sites.
Field Measurements
YSI EXO1 and Display
Report data from the sonde:TemperatureSpecific ConductanceSalinity (estuarine/marine only)pHDissolved OxygenDepth of measurement(s)
Presenter
Presentation Notes
Field measurements are collected using multiprobes or “sondes”. There are multiple types of sondes used by TCEQ regional staff and Clean Rivers Partners staff including YSI 600 XLMs, 6920’s, or the newer EXO’s. Additionally Hydrolabs and Manta sondes are used. The primary field parameters collected are water temperature, specific conductance, pH, dissolved oxygen, depth of measurement, and salinity at estuarine and marine sites.
Sondes and SensorsYSI 6920 and 6600 YSI EXO 1
pHConductivity/TemperatureDissolved Oxygenoptical
Presenter
Presentation Notes
Most sondes used for routine field measurements include sensors for pH, specific conductance/temperature, and dissolved oxygen. Salinity is calculated from the specific conductance and temperature values.
Calibration
• General Procedure• Calibrate in a temperature-controlled environment• Calibrate sensors in order
1. Specific conductance2. pH 3. Dissolved oxygen4. Depth (at first site)
Presenter
Presentation Notes
Sondes should be calibrated in a temperature-controlled environment such as a lab with access to a sink and deionized water for rinses. Sensors are calibrated in a specific order starting with specific conductivity, followed by pH (7.0 buffer and then either 4.0 or 10.0 buffer, dependent on the water body to be sampled, and lastly dissolved oxygen. The sonde depth sensor should be zeroed at the first monitoring site of the day.
Calibration• General Procedure con’t.• Rinse minimum 2x with calibration standard• Rinse minimum 2x with deionized water between
standards
• NEVER override a calibration error message without fully understanding the cause
Presenter
Presentation Notes
For more detailed explanations of the calibration process, reference the SWQM Procedures, Volume 1, Chapter 8.
Calibration• Each sonde has a dedicated
calibration logbook
• Record calibration/post calibration
• Maintenance
Presenter
Presentation Notes
Each sonde must have a logbook. Calibration and maintenance activities are recorded in the logbook.
Collecting Field Measurements and Water Chemistry Samples
• Freshwater Streams:• Collect samples from centroid of
flow upstream from bridges or road crossings
• Avoid backwater and stagnant pool areas in flowing water
Presenter
Presentation Notes
Field measurements and water samples should be collected as close to the centroid of flow as possible and upstream of bridges to avoid any influence from runoff from the bridge. Additionally, you want to avoid areas of stagnant or still water or backwater eddies in a flowing stream. The lower picture is the 2060 SWQM Team.
Collecting Field Measurements and Water Chemistry Samples
• Freshwater Streams:• Face upstream when filling containers
• Collect bacteria samples in sterile container
o Avoid contaminating samples with debris from banks
o Label containers clearly
Presenter
Presentation Notes
Despite both of the samplers facing each other, samples should be collected facing upstream. Bacteria samples should be collected in a sterile container. Care should be taken to avoid contamination of the sample by any floating debris or influence from the bank. All sample container labels including bottles and amber bags.
Sample Preservation—Routine
Preservation “kits” should contain safety glasses, gloves, and sodium bicarbonate for
spills
Pre-measured vials of 1:1 H2SO4 are a simple alternative to a
preservation kit
Place an “X” on the container lid and label container “Preserved-
H2SO4” or “H2SO4”
Add ~2mL of 1:1 H2SO4 to the sample container
Presenter
Presentation Notes
Water quality samples require different methods of preserving the integrity of the sample until it arrives at the lab and analyses can begin. Some may require the addition of acid or base while others may require the limiting exposure to sunlight. Still others may just require refrigeration.
Secchi Disk
The viewers eye level should be no greater than 2 meters above the surface. Slowly lower the disk vertically and note the depth at which it is no longer visible.
Then slowly raise the disk and note the depth at which it reappears.
Secchi disk transparency (00078) is the mean, in meters, of the two depths
Presenter
Presentation Notes
When making this measurement always; Remove sunglasses Take readings in open but shaded side of the boat Avoid direct sunlight
Secchi TubeStep 1. Fill the tube with sample water to the top. The disk should not be visible.
Step 2. Person 1—looks through the top of the tube.
Step 3. Person 2—slowly releases water through the bottom valve
Step 4. Person 1 says “stop” as soon as the disk becomes visible; Person 2 closes the valve
2030
10
Step 5. Record the
depth of the water in meters.
21 cm = 0.21 meters
Secchi Tube With Attached Disk
Field Parameters
Measurement of water quality parameters using a data sonde
Temperature Specific Conductance Salinity pH Dissolved Oxygen Depth of measurement(s)
Presenter
Presentation Notes
Field measurements from a boat will most often be profile samples.
Sampling With A Bucket
Collecting Field Measurements and Water Chemistry Samples
Field Observations may include:
• Weather• Water color/appearance• Odor• Watershed activities• Recreation• Substrate description• Other conditions that
might affect water quality
Presenter
Presentation Notes
Field observations are important qualitative information. They can provide clues that help interpret environmental data.
Field Observations
After Sampling –Post Calibration Check
• Verifies instrument accuracy • checks for electronic drift • may detect instrument issues that occurred in the field
Presenter
Presentation Notes
Post-calibration is really not a “calibration”. It’s actually a calibration verification. These checks are used to determine the validity of the data.
Questions
LINK TO FORM IN THE CHAT
1. How is the sample bottle containing the acid preservative identified?
2. Which of these is NOT a sensor on most of the sondesused in the SWQM program?
a. pHb. Salinityc. Dissolved oxygend. Temperature/Specific conductivity
3. How many times should a bucket or water collection device be rinsed?
https://forms.office.com/Pages/ResponsePage.aspx?id=pIMah86hekuBVjvNk6CPujOMcd-FkhdKttQ1QJNVwlZUNk1OVEVaUlc4SlY4T1FLUElaUEU1WVdXNi4u
Answers to Review Questions
• 1 – With an X on the lid and the preservative written on the bottle.
• 2 – Salinity
• 3 – Three times
Related Documents
