Probes/kits used in testing the water quality 2014 Group 4 Project

pH

Why is pH important? pH is an important indication of water quality. Aquatic organisms are sensitive to the pH of their environment. pH is an important indication of water quality. Aquatic organisms are sensitive to the pH of their environment. A pH range of 6.5 to 8.2 provides the optimum conditions for life of freshwater fish and bottom dwellers. A pH range of 6.5 to 8.2 provides the optimum conditions for life of freshwater fish and bottom dwellers.

Factors that Affect pH Levels Acidic rainfall Acidic rainfall Algal blooms Algal blooms Level of hard-water minerals Level of hard-water minerals Releases from industrial processes Releases from industrial processes Carbonic acid from respiration or decomposition Carbonic acid from respiration or decomposition

Vernier pH Probe Streams and lakes are often basic, with pH values between 7 and 8 Vernier pH Probe Streams and lakes are often basic, with pH values between 7 and 8

Turbidity

Turbidity Turbidity is a measure of water’s lack of clarity. Water with high turbidity is cloudy, while water with low turbidity is clear. Sources of Turbidity Soil erosion Soil erosion Urban runoff Urban runoff Industrial waste Industrial waste sewage treatment effluent sewage treatment effluent particulates particulates Abundant bottom- dwellers Abundant bottom- dwellers Microorganisms Microorganisms decaying plants and animals decaying plants and animals

Why Turbidity is important?  Decreases photosynthetic rate  Increases water temperature  Causing oxygen levels to fall. VERNIER TURBIDITY PROBE

Vernier Turbidity Probe Water is visibly turbid at levels above 5 NTU. Water is visibly turbid at levels above 5 NTU. Drinking water ranges between 0.5 to 1 NTU. Drinking water ranges between 0.5 to 1 NTU.

Temperature Temperature

Temperature The temperature of a body of water influences its overall quality. The temperature of a body of water influences its overall quality. One important aspect of water temperature is its effect on the solubility of gases, such as oxygen. One important aspect of water temperature is its effect on the solubility of gases, such as oxygen.

Factors that Affect Water Temperature Air temperature Air temperature Amount of shade Amount of shade Soil erosion and increasing turbidity Soil erosion and increasing turbidity Thermal pollution from human activities Thermal pollution from human activities

Water Temperature influences The amount of dissolved oxygen (DO) The amount of dissolved oxygen (DO) Rate of plant growth Rate of plant growth Metabolic rate of organisms Metabolic rate of organisms

Vernier Temp. Probe

Dissolved Oxygen (DO)

Dissolved Oxygen Oxygen dissolved in water is vital to the existence of aquatic organisms ( cellular respiration ) Oxygen dissolved in water is vital to the existence of aquatic organisms ( cellular respiration ) The concentration of dissolved oxygen, DO, is an important indicator of the water quality. The concentration of dissolved oxygen, DO, is an important indicator of the water quality.

How does Oxygen enter into the water?  Diffusion of Oxygen from atmosphere  Aeration of water - water moves over rocks and debris - wind and waves  Photosynthesis by aquatic plants Factors that affect DO levels Temperature Temperature Aquatic plants Aquatic plants Decaying organic material in water Decaying organic material in water Stream flow Stream flow pressure pressure Human activities Human activities

Vernier DO Sensor

Biochemical oxygen Demand (BOD) BOD is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. BOD is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. When nutrients and sunlight are overly abundant due to human influence, BOD is increased. When nutrients and sunlight are overly abundant due to human influence, BOD is increased. Oxygen consumed in the decomposition process robs other aquatic organisms of the oxygen they need to live. Oxygen consumed in the decomposition process robs other aquatic organisms of the oxygen they need to live.

Measuring Biochemical Oxygen Demand (BOD) After 5 days of incubation in the dark at 20 o C, the BOD bottles are unsealed and the final dissolved oxygen (DO) concentrations are read. After 5 days of incubation in the dark at 20 o C, the BOD bottles are unsealed and the final dissolved oxygen (DO) concentrations are read. The difference between the initial and final concentrations, The difference between the initial and final concentrations,

Total Dissolved Solids Solids are found in lake waters, both s uspended and dissolved. Solids are found in lake waters, both s uspended and dissolved. Suspended solids include silt, stirred-up bottom sediment, decaying plant matter, run offs or sewage effluent. Suspended solids include silt, stirred-up bottom sediment, decaying plant matter, run offs or sewage effluent. Dissolved solids include salts that yield ions such as sodium (Na + ), calcium (Ca 2+ ), magnesium (Mg 2+ ), bicarbonate (HCO 3 – ), sulfate (SO 4 2– ), or chloride (Cl – ). Dissolved solids include salts that yield ions such as sodium (Na + ), calcium (Ca 2+ ), magnesium (Mg 2+ ), bicarbonate (HCO 3 – ), sulfate (SO 4 2– ), or chloride (Cl – ). Total dissolved solids, or TDS, can be measured using a Vernier Conductivity Probe. Total dissolved solids, or TDS, can be measured using a Vernier Conductivity Probe.

Effects of high total solids Can be harmful to aquatic organisms Can be harmful to aquatic organisms Reduce water clarity (increased Turbidity) Reduce water clarity (increased Turbidity) Aesthetically unpleasing Aesthetically unpleasing Decrease photosynthetic rate Decrease photosynthetic rate Increase water temperature Increase water temperature

Vernier Conductivity Probe