What does ALAP test for?
Water samples gathered by ALAP volunteers are analyzed for: **
- Calcite Saturation Index
- Total Phosphorus
- Secchi Disk Transparency
- Dissolved Oxygen
** All scientific information generously provided by the Adirondack Watershed Institute **
PH – The pH level is a numeric measurement of acidity (concentration of hydrogen ions in water), that ranges from 1 to 14. On the pH scale, 7 is neutral, lower numbers are more acidic, and higher numbers are more basic. Many aquatic species struggle with growth and reproduction when pH levels fall below 5.5, whereas an acceptable pH level for Adirondack lakes is greater than 6.0
ALKALINITY – Alkalinity (acid neutralizing capacity) is a measure of the buffering capacity of water, and in lake ecosystems refers to the ability of a lake to absorb or withstand acidic inputs. In the northeast, most lakes have low alkalinities, which mean they are sensitive to the effects of acid rain.
CALICITE SATURATION INDEX – The Calcite Saturation Index (CSI) is another method used to determine the sensitivity of a lake to acidification. High CSI values indicate increasing sensitivity to acidic inputs.
TOTAL PHOSPHORUS – Phosphorus is one of the essential nutrients for life, and in northeastern lakes, is often the controlling or limiting nutrient in lake productivity. Total phosphorus measures all forms of phosphorous, both organic and inorganic, and its levels are directly related to the trophic status (water quality conditions) of a lake.
SECCHI DISK TRANSPARENCY – The Secchi Disk is a tool used to measure the clarity of water in lakes and ponds. It is determined by lowering the 20cm black and white disk (Secchi) into a lake to the depth where it is no longer visible from the surface.
NITRATE – Nitrogen, along with Phosphorus, is another one of the essential nutrients for life. Nitrate is the inorganic form of nitrogen, and occurs naturally in the environment. In excess of its natural production, however, it is an atmospheric pollutant. Elevated levels of nitrate concentrations may be indicative of lake acidification or wastewater pollution.
CHLORIDE – Chloride is an anion (negatively charged ion) that occurs naturally in surface waters, and typically in low concentrations (usually less than 1 ppm). Chloride above typical levels in Adirondack lakes (often caused by winter road de-icing, faulty septic systems, etc.) can alter the distribution and abundance of aquatic plant and animal species.
CONDUCTIVITY – Conductivity is the measurement of water’s ability to conduct electric currents, and will increase as dissolved minerals build up within a water body. Some high conductivity values are naturally occurring, while others may be indicative of pollution by road salt runoff or faulty septic systems.
COLOR – The measurement of color is usually used in lake classification to describe the degree to which the water body is stained due to the accumulation of organic acids. The color is affected by both dissolved material (metallic ions, organic acids) and suspended materials (silt and plant pigmentations).
ALUMINUM – Aluminum is one of the most abundant elements found within the earth’s crust. Dependent on the acidic level and composition of a water body, certain types of aluminum can bond with dissolved organic carbon, and can be potentially harmful or fatal to aquatic fauna.
DISSOLVED OXYGEN – Dissolved Oxygen analysis measures the amount of oxygen that is dissolved in water. If dissolved oxygen decreases as we approach the bottom of a lake, we know there is a great amount of bacterial decay happening, indicating an abundance of nutrients (such as phosphorous) collected on the bottom.