Skip to content Skip to left sidebar Skip to footer

Conductivity and Specific Conductivity Details

Conductivity in Haʻikū Streams

In Hawaiʻi, the health of our freshwater streams is vital for both the environment and public health. The Haʻikū Community Association is committed to keeping our streams clean and healthy! This webpage provides information on conductivity and specific conductivity measurements in Haʻikū streams and how they relate to water quality, although they are not directly used to assess public health safety for swimming.

What is Conductivity?

Conductivity and specific conductivity measurements are key indicators of water quality in streams. Conductivity is a measure of a water’s ability to conduct electricity, which correlates with the concentration of dissolved salts or ions [1]. Pure water is a poor conductor, while water containing dissolved salts and minerals conducts electricity more readily [2]. Therefore, conductivity readings can be a general indicator of the total amount of dissolved ions in the water.

Specific Conductivity

Specific conductivity is a measurement that considers the conductivity of the water after accounting for temperature. Specific conductivity is the conductivity corrected to a standard temperature, typically 25°C, allowing for comparisons between different water bodies [9]. This allows for more accurate comparisons between conductivity readings taken at different temperatures [3].

How Conductivity Relates to Stream Health

While not a sole indicator, elevated conductivity can suggest potential water quality concerns. High conductivity levels can indicate pollution from various sources, including agricultural runoff, urban wastewater, and industrial discharges [4]. Possible sources of increased conductivity include:

  • Natural Mineral Content: Streams flowing through areas with naturally high mineral content may have higher baseline conductivity [1].
  • Pollution Sources: Human activities like road runoff, fertilizer application, or wastewater discharge can introduce dissolved salts and minerals, raising conductivity [5].

Recreational Public Health Safety

For the residents and visitors of Haiku, knowing the conductivity levels in our streams is crucial for ensuring safe recreational activities. Elevated conductivity levels can suggest contamination by pollutants such as heavy metals, which pose health risks to those swimming, fishing, or engaging in other water activities [6]. Regular monitoring of conductivity helps us stay informed and take necessary precautions to protect public health [12].

Factors Affecting Conductivity

Several factors can influence conductivity levels in streams:

  • Geology: The underlying rocks and minerals can influence the natural level of dissolved ions in the water [1].
  • Salinity: Saltwater has a much higher conductivity than freshwater. In coastal areas, saltwater intrusion can increase a stream’s conductivity [7] [13].
  • Water Temperature: Warmer water conducts electricity more readily than colder water. Specific conductivity helps account for this temperature influence [2].
  • pH: Changes in pH can affect the solubility and mobility of ions, impacting conductivity levels [11].
  • Pressure: Variations in atmospheric pressure can influence the solubility of gases and minerals, thereby affecting conductivity [11].
  • Nitrites and Nitrates: High levels of these nutrients can increase conductivity by adding more dissolved ions to the water [14].
  • Phosphate: Similar to nitrates, high phosphate levels can raise conductivity by contributing additional ions [13].
  • Dissolved Oxygen (DO): While DO itself does not affect conductivity, the processes that deplete DO, such as organic matter decomposition, can release ions that increase conductivity (15).
  • E. Coli and Enterococcus: Presence of these bacteria can indicate fecal contamination, which is often associated with higher conductivity due to the influx of nutrients and organic matter [16].
  • Erosion and Sedimentation: Increased erosion can introduce minerals and ions into streams, raising conductivity levels (17).

Relating Conductivity to Other Parameters:

  • pH: While not directly linked, some dissolved salts can affect pH. However, conductivity doesn’t provide specific information about the types of dissolved ions that might influence pH [8].
  • Nutrients (Nitrates, Nitrites, Phosphates): These nutrients are often present as ions and can contribute to conductivity, though they are not the only source [1].
  • Dissolved Oxygen (DO): There is no direct relationship between conductivity and DO. However, some pollution sources that elevate conductivity might also contribute to DO depletion [9].

Erosion and Sedimentation

Erosion from construction sites or agricultural land can increase the amount of dissolved and suspended solids entering streams, potentially raising conductivity [10]. Sedimentation, the settling of these particles, can also impact stream health in other ways.

Using Conductivity Data

The Haʻikū Community Association is dedicated to providing transparent and accessible water quality data. Our website offers real-time and historical data on various water quality parameters, including conductivity levels. This information helps the community determine the safety of local streams for recreational use [12]. The Haʻikū Community Association website may publish conductivity data alongside other stream monitoring results. While not a standalone indicator of safety for swimming, long-term trends in conductivity can help identify potential pollution sources. This information can be used to guide efforts to protect stream health.

Looking Forward

By monitoring conductivity and other parameters, we can gain valuable insights into stream health. The Haʻikū Community Association encourages responsible land management practices to minimize pollution and protect our waterways. Visit our website (https://www.haikumaui.org/water-quality-data/) to access the latest water quality data and learn more about our efforts to protect our streams and ensure a healthy environment for all.

References:

  1. American Public Health Association (APHA). (2017). Standard Methods for the Examination of Water and Wastewater.
  2. Hem, L. (1989). Study and Interpretation of the Chemical Characteristics of Natural Water (3rd ed.). U.S. Environmental Protection Agency.
  3. U.S. Geological Survey. (2016, October 11). Specific Conductance (EC). Retrieved from https://www.usgs.gov/publications/specific-electrical-conductance
  4. U.S. Environmental Protection Agency (EPA). (2020). Water Quality Standards for Surface Waters.
  5. U.S. Environmental Protection Agency. (2023, April 26). Types of Water Pollution. Retrieved from https://www.epa.gov/environmental-topics/water-topics
  6. World Health Organization (WHO). (2011). Guidelines for Drinking-water Quality (4th ed.). WHO Press.
  7. National Oceanic and Atmospheric Administration. (n.d.). What is Salinity? Retrieved from https://coastwatch.noaa.gov/cwn/product-families/sea-surface-salinity.html
  8. How Does pH Affect the Availability of Nutrients? Retrieved from https://www epa.go
  9. U.S. Environmental Protection Agency. (2016, August 8). Effects of Nutrients on Surface Waters.
  10. Soil Quality Impacts from Erosion. (2015, November 19). United States Department of Agriculture (USDA) Natural Resources Conservation Service.
  11. Boyd, C. E. (2015). Water Quality: An Introduction. Springer.
  12. Hawaii Department of Health (HDOH). (2019). State of Hawaii Water Quality Monitoring and Assessment Report.
  13. Dodds, W. K. (2002). Freshwater Ecology: Concepts and Environmental Applications. Academic Press.
  14. Correll, D. L. (1998). The Role of Phosphorus in the Eutrophication of Receiving Waters: A Review. Journal of Environmental Quality, 27(2), 261-266.
  15. Wetzel, R. G. (2001). Limnology: Lake and River Ecosystems (3rd ed.). Academic Press.
  16. Soller, J. A., Schoen, M. E., Bartrand, T., Ravenscroft, J. E., & Ashbolt, N. J. (2010). Estimated Human Health Risks from Exposure to Recreational Waters Impacted by Human and Non-human Sources of Faecal Contamination. Water Research, 44(16), 4674-4691.
  17. Waters, T. F. (1995). Sediment in Streams: Sources, Biological Effects, and Control. American Fisheries Society.