2012/13
Chemistry instructions for sampling and analysis onsite. The parameters to measure, in the river water, are: pH, temperature, dissolved oxygen, nitrates and phosphorus (as phosphate). They are part of our syllabus and are well-tested scientifically for water sampling . • pH is the measure of the acid content of a substance (in this case water), it influences chemical processes in the waterbody and indicates how hospitable a waterbody is to aquatic life. • water temperature is also an important factor for determining what will live in a waterbody. It‟s largely determined by the amount of solar energy absorbed by the water, but it can also be indicative of where the water originates and how it is being used, for instance for industrial uses. • the amount of dissolved oxygen in a water body also affects whether a waterbody can provide optimal habitat for fish and other aquatic life. If compared to the maximum allowed by the temperature of the water, it tells more about capacity of self-purification and/or eutrophication • nitrates are a chemical compounds that can dissolve in water, they are some of the major nutrients needed for plant growth. Their overabundance is often related to eutrophication • phosphorus is another plant nutrient. Generally it is suspended in waters in its organic form or found in sediments. It limits the growth of aquatic plants. It‟s the major chemical responsible of eutrophication. There also two additional parameters: Biological oxygen demand (BOD5) and Fecal Coliform bacteria. • Biological oxygen demand (BOD5) is the amount of oxygen necessary to naturally breakdown or biodegrade and cleanse the river of organic matter suspended in the water. It can be related to the nutrient circle and/or to the degree of pollution in the water.