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Water Quality

Preserving the integrity of our marine environment.

What is water quality and why is it important?

Water quality is defined in terms of the chemical, physical and biological content of water.  It can be affected in many ways, often by nature’s own patterns, but also by human activities occurring in and around it.  

PRPA’s Marine Environmental Water Quality (MEWQ) program measures and monitors the state of the water in the Prince Rupert harbour.  By paying close attention to test results, we can learn a great deal about water quality.  For example, low levels of dissolved oxygen can increase stress on aquatic life, while high concentrations of heavy metals like lead and mercury can cause deformities and death among fish. Measuring chlorophyll and nutrients such as nitrates can determine if large amounts of plankton or algae are present, which deplete oxygen levels for fish and other organisms.

How is water quality measured?

PRPA staff collect water samples four times a year, from 32 sites throughout in the inner and outer harbour to represent a full range of port operations. The samples are then shipped to labs where they are analyzed to determine their general properties, as well as the presence of metals, nutrients, algae, bacteria and polycyclic aromatic hydrocarbons (PAH).

In addition to collecting samples, the crew of PRPA’s port patrol boat, the Charles Hays, also measure temperature, conductivity, dissolved oxygen, dissolved solids, salinity and pH levels at each site every two weeks.  Measurements are taken at depth profiles of one-metre intervals are useful to see how water quality changes at various depths, and help build our baseline water quality data. The high frequency of testing ensures PRPA is able to recognize and respond to potential marine pollution incidents in a timely manner.

The Water Quality Index identifies five categories of water quality: excellent, good, fair, marginal and poor.

What determines poor water quality?

Water quality objectives are highly dependent on end uses and natural baselines, but for comparison purposes water results are compared to standards developed by:

•    Canadian Council of Ministers of Environment’s Canadian Water Quality Guidelines for the Protection of Aquatic Life, Marine

•    BC Approved Water Quality Guidelines for the Protection of Aquatic Life

The current water quality in Prince Rupert harbour is generally good, and provides a healthy environment for our primary concerns of aquatic life and wildlife.  The introduction of MEWQ’s monitoring and measuring is providing the baseline data that allows us to record and respond to any changes as they occur.