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Water pH Details

pH is a measure of acidity (or basicity) on a scale from 0 to 14, with 7 being neutral. Freshwater streams should ideally have pH levels between 6.5 and 8.5 to support aquatic life and be safe for recreational use (U.S. Environmental Protection Agency [EPA], 2022). Deviations from this range can indicate the presence of pollutants or other environmental issues that may harm aquatic organisms and pose risks to human health

Factors Affecting pH Levels

Several factors can influence the pH levels in Hawaiʻi’s streams:

  1. Natural Processes: Volcanic activity, rainfall, and the presence of certain minerals can naturally alter pH levels (Hawaiʻi Department of Health [DOH], 2021).
  2. Human Activities: Runoff from agricultural lands, urban areas, and industrial sites can introduce pollutants that affect pH (EPA, 2022).
  3. Erosion and Sedimentation: Soil erosion and sedimentation can introduce materials that change the acidity or basicity of the water (Hawaiian Ecosystems at Risk project [HEAR], 2019).

Relationship Between pH and Other Water Quality Indicators

  1. Turbidity: High turbidity, or cloudiness of water, often results from erosion and sedimentation. Suspended particles can affect pH by introducing acidic or basic materials (USGS, 2018).
  2. Dissolved Oxygen: The availability of dissolved oxygen is crucial for aquatic life and is influenced by pH levels. Extreme pH values can reduce the solubility of oxygen in water, affecting aquatic organisms (EPA, 2022).
  3. Specific Conductivity: This measures the water’s ability to conduct electrical current, which is related to the concentration of dissolved ions. Changes in pH can alter the ionic composition of water (USGS, 2018).
  4. Nitrate and Nitrite: These nutrients, often from agricultural runoff, can influence pH by contributing to eutrophication, which can cause algal blooms and subsequent pH fluctuations (EPA, 2022).
  5. Phosphate: Like nitrate and nitrite, phosphate can lead to eutrophication and affect pH levels (DOH, 2021).
  6. Silicon Dioxide: This natural component can impact water clarity and, indirectly, pH by influencing the levels of dissolved and suspended solids (HEAR, 2019).
  7. E. coli and Enterococcus: These bacteria are indicators of fecal contamination. High levels can be associated with runoff events that may also affect pH by introducing organic matter (DOH, 2021).

Public Health and Safety

Maintaining pH levels within the safe range is essential for public health and recreational safety. The Haʻikū Community Association continuously monitors stream pH levels and provides this data on our website. Safe pH levels for recreational activities typically range from 6.5 to 8.5 (EPA, 2022). Levels outside this range may indicate pollution or other environmental issues, and caution should be exercised when using the streams.

How to Use pH Data

The HCA provides real-time pH data for local streams on our website (https://www.haikumaui.org/water-quality-data/). Community members and visitors can use this information to determine the safety of a stream on any given day. Here are some tips for using the information:

  • Check the Latest Measurements: Before heading out for recreational activities, review the most recent pH measurements posted on our website.
  • Understand the Implications: Be aware that pH levels outside the safe range (6.5-8.5) can indicate potential health risks.
  • Stay Informed: Follow any advisories or alerts issued by the HCA regarding water quality and safety.

Conclusion

By monitoring and understanding pH levels, the Haʻikū Community Association aims to ensure the health of our streams and the safety of our community. For more detailed information and the latest pH data, please visit our website.

References

EPA. (2022). Water quality criteria. U.S. Environmental Protection Agency. https://www.epa.gov/wqc

Hawaiian Ecosystems at Risk project. (2019). Impacts of soil erosion. https://hear.org

Hawaiʻi Department of Health. (2021). Water quality monitoring and assessment report. https://health.Hawaiʻi.gov/cwb

U.S. Geological Survey. (2018). Water properties: pH. https://www.usgs.gov/special-topic/water-science-school/science/water-properties-ph