1. What, Why, & How

2. a limiting nutrient for aquatic plant growth sources include: atmospheric deposition organic matter decomposition excretion by organisms urban and agricultural run off (human activity) Nitrates…

3. Nitrate is highly soluble in water and is stable over a wide range of environmental conditions Excessive amounts of nitrates (and phosphorus) can cause explosive algae and aquatic plant growth Significance of Nitrate…

4. Excessive concentrations may be harmful to animals, specifically humans In intestines, nitrate is converted to nitrite which reacts with hemoglobin to produce methemoglobin Methemoglobin does not efficiently carry oxygen resulting in methemoglobinemia In the same way, high nitrate (and subsequent nitrite) levels can affect fish Nitrite reacts with hemoglobin to form methemoglobin which cannot carry oxygen effectively Fish will suffocate even if there are adequate DO levels in the water Significance of Nitrate…

5. LaMotte kits report the amount of nitrate in a water sample as NO3 - -N (nitrate- nitrogen) NO3 - -N levels Natural waters - lower than 1 mg/L is normal Fresh water (U.S.) - above 10 mg/L is considered unsafe for human consumption Acceptable Levels

6. Measuring Nitrates… Nitrate cannot be measured directly. It must first be converted to nitrite using an oxidation-reduction reaction. Cadmium is used for this reaction. The amount of nitrite is then determined by color.

7. Sample Collection & Reporting Follow directions in the LaMotte Nitrate test kit to test the water sample. Repeat 3 times. Values should agree with the precision of the kit. If not, discard outlier(s).

8. Nitrates Measuring [Nitrate + Nitrite] NO 3 - NO 2 - Step 1. The 1 st reagent converts nitrate to nitrite

9. NO 3 - + NO 2 - Step 2. The 2 nd reagent reacts with nitrite and creates color. The amount of [nitrate + nitrite] is determined by measuring the color intensity. Nitrates Measuring [Nitrate + Nitrite]

10. The 2 nd reagent reacts with nitrite and creates color. Repeat step 2 only to measure the amount of nitrite alone in the water sample. NO 2 - Nitrates Measuring [Nitrate + Nitrite]

11. To calculate the amount of nitrate in the sample: [Nitrate] = [Nitrate + Nitrite] – [Nitrite] Nitrates Calculating [Nitrate]

12. Perform every six months to test kit chemicals and technique (prepare fresh solutions each time). Follow the instructions in the GLOBE Teacher’s Guide on how to prepare a 2mg/L Standard using the stock nitrate standard. Quality Control

13. For Help AMSTI-GLOBEThe GLOBE Program www.amsti.org/globe www.globe.gov Lynn VaughanJerry CobbsAMSTI-GLOBE Resource SpecialistTechnology Specialist lynn@amsti.org jerry@amsti.org Robin Nelson AMSTI-GLOBE Administrator robin@amsti.org