D.O.
DO is the level of oxygen dissolved in water, and it is measured in either mg/L or ppm (1 mg/L=1 ppm). Normal levels are between 5 and 6 mg/L, which is about 90% saturation. DO is important because oxygen is essential for organisms to survive. The factors that affect DO are temperature and BOD. Colder water means more DO. Photosynthesizing algae also increases DO.
B.O.D.
BOD measures the consumption of oxygen by microbes. Normal levels for BOD are about 5 mg/L. Debris, dead organisms, manure, effluents from pulp and paper mills, wastewater treatment plants, feedlots, food-processing plants, failing septic systems, and stormwater runoff all increase BOD. Microbes that don’t photosynthesize use oxygen to metabolize organic matter.
Ammonia and Nitrate
Nitrate is the most readily available form of nitrogen in rivers. Ammonia, a more toxic nitrogen compound, is converted to nitrates and thus less common in rivers. We tested for both of these forms of nitrogen this winter. Non-toxic nitrogen is consumed by algae and plankton in rivers. As the nitrates decrease due to algae blooms, the existing algae population dies off, decomposes, and results in an anoxic zone in the water.
Temperature
Air temperature, shade, soil erosion (which increases turbidity), and thermal pollution from human activities all have an effect on water temperature. In turn, the water temperature has an effect on the solubility of dissolved oxygen, rate of plant growth, and the metabolic rate of organisms. The advantage of low water temperature is that more oxygen can be dissolved. However, warm water temperatures can cause an increase in the photosynthetic rate of aquatic plants and algae. This, in turn, increases dissolved oxygen (DO), which can be beneficial to the ecosystem.
E. coli
E. coli (Escherichia coli) is a bacteria found in most animal's digestive system. It is measured by the number of colonies forming per 100 milliliters of water collected (unit/mil). Humans can pick up these harmful bacteria by drinking contaminated water, eating uncooked foods, and contact with fesces (swimming in a contaminated river). There should be no E. coli in drinkable water. Rainfall, melted snow, waste, sewage system failures, and livestock farms draining into rivers are all factors that increase E. coli.
Benthic
The benthic count of aquatic bugs is an excellent indicator of long-term health of a river. Species such as stoneflies, mayflies and dragonflies are good indicators of a healthy system, while worms, black fly larva and midges are tolerant of unhealthy water. Mussels and snails are also indicators of a healthy river. The combination of the number of species and their relative abundance is important in determining the biodiversity of a system. Land use in the watershed such as farming practices, runoff from streets, and siltation affects the benthic count.
Phosphate
Phosphate is an inorganic ion that is a salt of phosphoric acid. A phosphate level of 0.10 mg/L is optimal for a stream or river. Most natural waters contain a phosphate level of around 0.02 mg/L. An increase in phosphate can be caused by soil erosion, rock weathering, agricultural runoff, industrial wastewater discharges, animal feed lots and manure storage runoff. Phosphates, along with nitrates, can result in eutrophication.
pH
pH measures the acidity or alkalinity concentration in water. pH is measured on a scale of 1-14, with 1-6.9 being acidic, 7 being neutral, and 7.1-14 being basic. Most natural water has a pH of between 6.5 and 8.5. Optimum pH for river water is around 7.4. A pH higher or lower than the 6-8 range can decrease the survival rate of aquatic organisms, which in turn lead to a loss in stream ecosystem diversity. pH can be affected by natural occurrences such as limestone, acid rain, or decaying leaves in streams. On the other hand, it can be affected by automotive exhaust runoff and agricultural runoff.
Conductivity
Conductivity measures monatomic and polyatomic ion concentration in water. This would include salinity and the concentration of minerals and contaminants. The erosion of minerals from soil, precipitation from the atmosphere, and runoff from impermeable surfaces can increase conductivity.
Turbidity
Turbidity is the cloudiness or haziness caused by suspended particles and dissolved solids. Urban runoff, rainfall, algae growth, and natural riffles all affect the turbidity level of a river. Turbidity is measured in NTUs and drinking water must not exceed .3 NTU while other systems such as rivers must be below 5 NTUs in order to be healthy. High turbidity decreases the ability for plants and algae to photosynthesize resulting in low dissolved oxygen. The suspended solids can also interfere with respiration and filter feeding.
DO is the level of oxygen dissolved in water, and it is measured in either mg/L or ppm (1 mg/L=1 ppm). Normal levels are between 5 and 6 mg/L, which is about 90% saturation. DO is important because oxygen is essential for organisms to survive. The factors that affect DO are temperature and BOD. Colder water means more DO. Photosynthesizing algae also increases DO.
B.O.D.
BOD measures the consumption of oxygen by microbes. Normal levels for BOD are about 5 mg/L. Debris, dead organisms, manure, effluents from pulp and paper mills, wastewater treatment plants, feedlots, food-processing plants, failing septic systems, and stormwater runoff all increase BOD. Microbes that don’t photosynthesize use oxygen to metabolize organic matter.
Ammonia and Nitrate
Nitrate is the most readily available form of nitrogen in rivers. Ammonia, a more toxic nitrogen compound, is converted to nitrates and thus less common in rivers. We tested for both of these forms of nitrogen this winter. Non-toxic nitrogen is consumed by algae and plankton in rivers. As the nitrates decrease due to algae blooms, the existing algae population dies off, decomposes, and results in an anoxic zone in the water.
Temperature
Air temperature, shade, soil erosion (which increases turbidity), and thermal pollution from human activities all have an effect on water temperature. In turn, the water temperature has an effect on the solubility of dissolved oxygen, rate of plant growth, and the metabolic rate of organisms. The advantage of low water temperature is that more oxygen can be dissolved. However, warm water temperatures can cause an increase in the photosynthetic rate of aquatic plants and algae. This, in turn, increases dissolved oxygen (DO), which can be beneficial to the ecosystem.
E. coli
E. coli (Escherichia coli) is a bacteria found in most animal's digestive system. It is measured by the number of colonies forming per 100 milliliters of water collected (unit/mil). Humans can pick up these harmful bacteria by drinking contaminated water, eating uncooked foods, and contact with fesces (swimming in a contaminated river). There should be no E. coli in drinkable water. Rainfall, melted snow, waste, sewage system failures, and livestock farms draining into rivers are all factors that increase E. coli.
Benthic
The benthic count of aquatic bugs is an excellent indicator of long-term health of a river. Species such as stoneflies, mayflies and dragonflies are good indicators of a healthy system, while worms, black fly larva and midges are tolerant of unhealthy water. Mussels and snails are also indicators of a healthy river. The combination of the number of species and their relative abundance is important in determining the biodiversity of a system. Land use in the watershed such as farming practices, runoff from streets, and siltation affects the benthic count.
Phosphate
Phosphate is an inorganic ion that is a salt of phosphoric acid. A phosphate level of 0.10 mg/L is optimal for a stream or river. Most natural waters contain a phosphate level of around 0.02 mg/L. An increase in phosphate can be caused by soil erosion, rock weathering, agricultural runoff, industrial wastewater discharges, animal feed lots and manure storage runoff. Phosphates, along with nitrates, can result in eutrophication.
pH
pH measures the acidity or alkalinity concentration in water. pH is measured on a scale of 1-14, with 1-6.9 being acidic, 7 being neutral, and 7.1-14 being basic. Most natural water has a pH of between 6.5 and 8.5. Optimum pH for river water is around 7.4. A pH higher or lower than the 6-8 range can decrease the survival rate of aquatic organisms, which in turn lead to a loss in stream ecosystem diversity. pH can be affected by natural occurrences such as limestone, acid rain, or decaying leaves in streams. On the other hand, it can be affected by automotive exhaust runoff and agricultural runoff.
Conductivity
Conductivity measures monatomic and polyatomic ion concentration in water. This would include salinity and the concentration of minerals and contaminants. The erosion of minerals from soil, precipitation from the atmosphere, and runoff from impermeable surfaces can increase conductivity.
Turbidity
Turbidity is the cloudiness or haziness caused by suspended particles and dissolved solids. Urban runoff, rainfall, algae growth, and natural riffles all affect the turbidity level of a river. Turbidity is measured in NTUs and drinking water must not exceed .3 NTU while other systems such as rivers must be below 5 NTUs in order to be healthy. High turbidity decreases the ability for plants and algae to photosynthesize resulting in low dissolved oxygen. The suspended solids can also interfere with respiration and filter feeding.