Mayor's Report - October 2008

As part of its Liquid Waste Management Plan (LWMP) adopted in 2002, Metro Vancouver committed to undertake an ambient monitoring program of the Burrard Inlet receiving environment in areas where the water quality could potentially be affected by wastewater and/or storm water.

In 2006, Metro Vancouver developed a Burrard Inlet Ambient Monitoring Program to allow the assessment of ambient conditions through water, sediment, fish health and fish tissue chemistry (biota) monitoring in the Outer Harbour, Inner Harbour, Central Harbour, Port Moody Arm and Indian Arm of Burrard Inlet.

Water column and biota monitoring were undertaken in 2007, and the draft report on the water column sampling results was recently presented to Metro Vancouver’s Environment Committee. (The draft reports for the 2007 biota monitoring and the 2008 sediment monitoring are expected in the late fall of 2008.) The 2007 Burrard Inlet Ambient Monitoring Program involved weekly sampling at seven sites and at two depths between October 29^th and November 26^th, 2007, during a period of high runoff. The “top” or “near-surface” sample was collected one (1) metre below the surface to capture the lens of freshwater runoff. The “bottom” or “near-bottom” sample was taken two (2) metres above the ocean floor.

The spatial variation in water quality appeared to be related primarily to physical oceanographic factors rather than discharges from Metro Vancouver or industrial sources. Dissolved oxygen concentrations showed the lowest levels at the two Indian Arm sites where the configuration of the basin restricts deep water renewal, promoting prolonged periods of oxygen depletion.

Dissolved oxygen concentrations below the Burrard Inlet Water Quality Objectives (6.5 mg/L) occurred in one or more near-bottom samples from all sites and in one near-surface sample from the Inner Harbour and the Port Moody Arm. Enterococci exceeded the 30-day average objective in all near-bottom sampling locations from the Outer, Inner and Central Harbours. In addition, enterococci in the near-surface samples from the Inner Harbour and fecal coliforms in the near-bottom samples from the same site exceeded their respective 30-day average objectives. Potential contributors to elevated microbiological parameters and metals, and depressed dissolved oxygen concentrations include stormwater run-off from parks, residential, industrial, and commercial properties, and wet-weather discharges from Combined Sewer Overflows (CSOs).

A review of previous water quality data revealed that historically, dissolved oxygen concentrations have been depressed throughout Burrard Inlet. In the past, several other parameters, including fecal coliforms, enterococci, copper, mercury, lead and zinc have failed to meet Burrard Inlet Water Quality Objectives. The 2007 ambient water quality monitoring program results are consistent with the historical data for dissolved oxygen and bacteria. However, the 2007 metals met the water quality objectives, suggesting a possible improvement in water quality with time.

The results of the first year of the Burrard Inlet Ambient Monitoring Program can be put in perspective by addressing the following four questions:

What is the overall health status of Burrard Inlet?
Generally, the data shows that water quality in Burrard Inlet is protective of aquatic life. Metro Vancouver is partnering with the Burrard Inlet Environmental Action Program (BIEAP) in the development of Best Management Practices (BMPs) to manage non-point source pollution. The BMPs will be in the form of educational materials for distribution to local industry and the public. The City of Vancouver is also committed to addressing Combined Sewer Outfall (CSO) issues through its CSO program, which includes physical separation of storm and sanitary sewers.

Is the environmental quality the same from year-to-year?
The results of the 2007 ambient water quality monitoring program are consistent with the historical data for dissolved oxygen and bacteria. Previous results for several other parameters, including fecal coliforms, enterococci, copper, mercury, lead and zinc have failed to meet Burrard Inlet Water Quality Objectives. However, the 2007 metals results generally met the water quality objectives.

How does environmental quality vary within Burrard Inlet?
With the exception of microbiological parameters, spatial variation in water quality appeared to be related primarily to physical oceanographic factors rather than discharges from Metro Vancouver or industrial sources. Using average concentrations, bacterial results were higher in the Outer, Inner and Central Harbours.

Does the observed water quality suggest any significant environmental concerns?
Dissolved oxygen levels in deep water samples remain a concern. However, these occurrences may be the result of physical oceanographic factors. Total boron concentrations fall within the expected range for Canadian coastal marine waters.

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