Test+3+-+Turbidity

﻿Turbidity

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 Turbidity is a measure of water's lack of clarity. High water turbidity is cloudy, while water with a low turbidity is clear. The cloudiness is produced by light reflection off particles in the water; meaning, the more water particles, the higher turbidity. =====

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 Many different things help contribute to the turbidity of water. The faster in stream flow due to a heavy rain or lower vegetation in stream banks can speed up the process of soil erosion. The less vegetation the more added suspended particles. =====

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 Runoff of different types of solids may add turbidity to the stream. Agricultural runoff often contains suspended soil particles. Many other types of runoff include industrial wastes, water treatment plant effluent, and urban runoff from parking lots, roads, rooftops, etc. =====

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 Bottom dwelling aquatic organisms, such as catfish, can contribute to turbidity of the water by stirring up the sediments at the bottom of the stream. Organic matter, such as decaying plants, suspended in the water can also increase the turbidity of water. =====

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 High turbidity will decrease the amount of sunlight able to penetrate the water, therefore decreasing the photosynthetic rate. In lowering the clarity also makes water less aesthetically pleasing. This might not be harmful directly, but it’s certainly undesirable for many water uses. =====

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 When the water is cloudy, sunlight warms the particles, making the particles absorb sunlight, warming the surrounding water. However, this could create problems with the increase of temperature. However, you can’t always assume clear water is healthy. Slightly turbid water can be perfectly healthy, while clear water could still contain unseen toxins or unhealthy levels of nutrients. =====

High Turbidity(picture)

Testing Procedures
1. Position the computer safely away from the water. Keep water away from the computer at all times. 2 . Plug the turbidity sensor into Channel 1 of the Vernier interface. **Important** : Let the Turbidity Sensor warm up for two minutes before proceeding to the next step. 3. Prepare the computer for dat collection by opening the file "03 Turbidity" from the //Water Quality with Vernier// folder of //LoggerPro//. 4. You are now ready to calibrate the Turbidity Sensor. First Calibration Point a. Choose Calibrate > CH1: Turbidity (NTU) from the Experiment menu and then click [calibrate now] b. Prepare a blank by rinising the glass turbidity cuvette with distilled water, then filling it with distilled water so that the bottom of the meniscus is even with the top of the white line. Place the lid on the cuvette. Gently wipe the outside with a soft, lint-free cloth or tissue. c. Check the cuvette for air bubbles. If air bubbles are present, gently tap the bottom of the cuvette on a hard surface to dislodge them. d. Holding the cuvette by the lid, place it in the Turbidity Sensor. Make sure that the mark on the cuvetter is aligned with the mark on the Turbidity Sensor. Close the lid. e. Type ** 0 ** (the value in NTU) in the edit box. f. When the displayed voltage reading for Reading 1 Stabilizes, Click (keep). g. Remove the cuvette and set aside for use in Step 5. Second Calibration Point h. Obtain the cuvette containing the Turbidity Standard (100 NTU) and gently invert it four times to mix in any particles that may have settled to the bottom. Important: Do not shake the standard. Shaking will introduce tiny air bubbles that will affect turbidity. i. Wwipe the outside with a soft, lint-free cloth or tissue. j. Holding the standard by the lid, place it in the Turbidity Sensor. Make sure that the mark on the curvette is aligned with the mark on the Turbidity Sensor. Close the lid. k. Type the ** 100 **(the value in NTU) in the edit box. l. When the displayed voltage reading for Reading 2 stabilizes, click [keep], then click [done] 5. You are now ready to collect turbidity data. a. Gently invert the sample water to mix in any particles that may have settled to the bottom. ** Important **:Do not shake the sample. Shaking will introduce tiny air bubbles that will affect turbidity. b. Empty the water from the cuvette used in Step 4. c. Rinse the cuvette with sample water, then fill it with sample water so that the bottom of the meniscus is even with the top of the white line. Place lid on the cuvette. Gently wipe the outside with a soft, lint-free cloth or tissue. d. Check the cuvette for air bubbles. If air bubbles are present, gently tap the bottom of the cuvette on a hard surface to dislodge them. e. Holding the cuvette by the lid, place it into the Turbidity Sensor. Make sure it is in the same orientation in the cuvette slot that it was before. Close the lid of the Turbidity Sensor. f. Click [>collect] to begin data collection. g. Click [keep] to begin a 10 s sampling run. Keep the lid closed for the next 10 seconds. **Note** : Particles in the water will settle over time and show a slow downward drift in turbidity readings. Therefore, start data collection soon after placing the cuvette in the sensor. h. When the sampling run is complete, stop data collection and record the average temperature on the Data & Calculations sheet. 6 . Return to Step 5 to obtain a second reading. When both readings have been taken, rinse the cuvette with distilled water.

DATA & CALCULATIONS
Turbidity Stream or lake: site name: site number: <span style="color: #f2c018; font-family: Georgia,serif;">date: <span style="color: #f2c018; font-family: Georgia,serif;">time of day: <span style="color: #f2c018; font-family: Georgia,serif;">Student name: <span style="color: #f2c018; font-family: Georgia,serif;">Student name: <span style="color: #f2c018; font-family: Georgia,serif;">Student name:

(NTU) || Turbitidy (NTU) ||  || <span style="color: #00ff00; font-family: Georgia,serif;">Column Procedure : <span style="color: #f2c018; font-family: Georgia,serif;">A. Record turbidity as read from the computer.
 * Column || A ||
 * Reading || Turbidity
 * 1 ||  ||
 * 2 ||  ||
 * Average

<span style="color: #00ff00; font-family: Georgia,serif;">Field Observations (e.g., weather, geography, vegetation along stream):