WQ_Analysis_Tuesday (2)

Introduction to Environmental Science Lab: Water Quality Analysis Purpose The objectives of this lab exercise are to:  Understand the application and purpose of water quality monitoring and analysis  Perform basic water quality measurements Key Terms calibration, standard, parameter, nutrients, eutrophication, quality control Materials  Computer  Water Quality data  Nutrient test kits  Water samples Introduction Water is continually moving around, through, and above the Earth as water vapor, liquid water, and ice. In fact, water is continually changing its form. The Earth is pretty much a "closed system," like a terrarium. That means that the Earth neither, as a whole, gains nor loses much matter, including water. This means that the same water that existed on Earth billions of years ago is still here and is continuously being recycled around the planet. Water is known as the universal solvent because most substances will dissolve when placed in a water-based solution, and these dissolved substances are generally invisible, odorless, and tasteless. There are times, however, when concentrations of substances other than hydrogen and oxygen exceed acceptable limits for the purpose which the water is being used (i.e. drinking, swimming, aquaculture--raising fish/shellfish, etc.). In these cases, the water is referred to as being contaminated, which implies that the water contains “ harmful ” or “ objectionable ” substances. Water Quality Analysis Water Quality Analyses use some parameters that serve as indicators, or sometimes as direct measures, of the quality of water as intended for a specific purpose. What are some of the parameters investigated when determining water quality? It really depends on what type of water sample you are investigating and why. This may cover a broad range and must therefore be put into context. The investigators must clearly define their purpose for conducting water quality analyses and select the appropriate parameters in order to answer their questions. For example: if we wanted to know if recreational waters were safe to use, we would test our water sample for fecal coliform levels. The most common form of these bacteria is E. coli and is associated with the fecal material of warm-blooded animals. The presence of fecal coliform bacteria in aquatic environments indicates that the water has been contaminated with the fecal material of man or other animals. Fecal coliform bacteria may occur in ambient water as a result of the overflow of domestic sewage or nonpoint sources of human and animal waste. The presence of fecal contamination (at a high concentration) is an indicator that a potential health 1

risk exists for individuals exposed to this water. In southwest Florida heavy rainfall often contributes to these conditions because water treatment facilities become overwhelmed and septic tanks leak. This parameter would also be a logical choice for determining if water quality was suitable for shellfish harvesting (who wants to eat raw sewage???). Nutrients, especially nitrogen and phosphorous, are indicators of nutrient pollution of water. Although both of these nutrients are required for growth and maintenance of aquatic organisms, excessive concentrations (a condition known as eutrophication ) may lead to rapid growth of bacteria, algae, and other phytoplankton. Decomposers (bacteria and fungi) use oxygen to break down the dead and dying plankton (remember detritus ?) and in doing so may deplete the amount of oxygen available for other organisms. This can cause permanent changes in the ecosystem and result in eutrophication. Eutrophication is the process whereby a water body transitions from a pristine, nutrient poor condition to a stagnated, nutrient rich one. The process of eutrophication may occur naturally or be accelerated by anthropogenic influence via run-off of fertilizer or sewage. In this lab, you will use a nutrient kit to test the water for pH levels, ammonia, nitrites, and nitrates. Other contaminants that might be monitored include lead, mercury, and copper. Excessive levels of these elements (which are all metals, mercury is a heavy metal—rock on! ) may cause physiological impairment of the nervous system and kidneys and may result in death. Parameters  Salinity Salinity is the total of all non-carbonate salts dissolved in water, usually expressed in parts per thousand (1 ppt = 1000 mg/L). Unlike chloride (Cl–) concentration, you can think of salinity as a measure of the total salt concentration, comprised mostly of Na+ and Cl– ions. Even though there are smaller quantities of other ions in seawater (e.g., K+, Mg2+, or SO42–), sodium and chloride ions represent about 91% of all seawater ions. Salinity is an important measurement in seawater or in estuaries where freshwater from rivers and streams mixes with salty ocean water. The salinity level in seawater is fairly constant, at about 35 ppt (35,000 mg/L), while brackish estuaries may have salinity levels between 1 and 10 ppt. Since most anions in seawater or brackish water are chloride ions, salinity can be determined from chloride concentration. The following formula is used: salinity (ppt) = 0.0018066 * Cl - (mg/L) A Chloride Ion-Selective Electrode can be used to determine the chloride concentration, which is converted to a salinity value using the above formula.  pH The pH of a solution is actually the measure of the hydrogen (H + ) ions in solution. The lower the pH reading, the more H + ions there are in solution. pH is represented on a logarithmic scale, with neutral water having a pH value of 7. Anything below 7 is an acid; anything above 7 is a base. Rainwater is normally a little acidic, having a pH around 5.6 because of dissolved carbon dioxide. Seawater is usually a little basic, having a pH around 8. Most aquatic organisms, including fish, prefer a pH of between 6.5 and 8.2. When the pH deviates beyond these levels, fish are affected; for example, some fish will produce deformed 2

was not too acidic, the ammonium read as fresh and the nitrates read 0 (both good indicators for the water being able to hold life). Our sample could have been innaccurate. 3) According to SECOORA’s data portal, the pH on October 18 th at 3 p.m. was 6.7; that was two years ago, but the same date and roughly the same time as we took our pH reading last week. How do the two pH readings compare? Discuss at least two reasons they might be similar/different (2 points). Two years ago with a 6.7 pH, the water was slightly acidic but closer to neutral than it is now, with a reading of 8 pH and being alkaline. They are about 1 off, so still pretty similar. Two reasons it might have changed slightly is that in the past two years, usf st pete installed the water goat so maybe that improved the water quality. Another reason is more broadly st pete may have better water quality laws. 4) Ammonium, nitrates, and nitrites are all compounds containing nitrogen. What happens when an estuarine environment receives excess nutrients like nitrogen? Write about at least two consequences of an overload of nutrients in a system like Clam Bayou (3 points). When an estuarine environment receives excess nutrients such as Nitrogen, it is called eutrophication. This causes an algal bloom, which algae overgrows and covers the surface of the water, preventing plants at the bottom of the water from being able to perform photosynthesis. Two consequences of an overload of nutrients in an estuarine environment are that they can disrupt food webs, damage habitats, and deplete oxygen (to the point organisms must either relocate or die). PART TWO 1) Use the Clam Bayou data table below to create two graphs. For each graph you will choose two parameters. Create a line graph with both parameters represented on the y- axis, and time on the x-axis. To do this you will have to create two y-axes, since you’re looking for trends in the data. You will have two graphs when you are done with this part of the assignment. Don’t forget axis labels and a title. (2 points per graph) Note that you need to add a secondary axis to make your graphs look their best. Here is a helpful website on adding a secondary axis to an excel chart: https://www.geeksforgeeks.org/plot-multiple-data-sets-on-the-same-chart-in-excel/ Table: Clam Bayou Parameters on October 19, 2019 Time Turbidit y (NTU) Chlorophyll (micrograms/L ) Dissolved Oxygen Concentration (micrograms/L ) pH blue green algae (micrograms/L ) 4

14:00:00Z 3.47 4.3 3.36 7.96 10.29 14:12:00Z 4.69 5.33 3.09 7.96 13.13 14:24:00Z 6.28 5.03 3.19 7.93 12.44 14:36:00Z 3.75 4.39 3.44 7.98 10.02 14:48:00Z 4.38 4.34 3.61 7.98 9.6 15:00:00Z 4.6 4.71 3.37 7.96 11.29 15:12:00Z 5.12 4.1 4.23 7.99 9.39 15:24:00Z 8.89 7.94 2.91 7.92 20.16 15:36:00Z 5.67 5.31 3.47 7.93 14.04 15:48:00Z 7.2 5.89 3.7 7.96 16.48 16:00:00Z 7.97 6.88 4.3 8 15.88 16:12:00Z 9.79 6.8 3.75 7.97 17.95 16:24:00Z 7.51 6.18 4.21 7.99 15.18 16:36:00Z 8 6.04 4.04 7.99 15.81 16:48:00Z 7.54 6.02 4.53 8.02 16.69 5