Moxlie Creek

Comments on Westman Mill Development, 510 State Ave NE, Olympia. September 25, 2017

Westman Mill 01.jpg
Westman Mill development area.

The area on State street that is today (February 2018) being readied for development, is adjacent to East Bay. If Moxlie Creek were daylighted, this would be the area of intertidal exchange, the estuary. This is the only place it can be located. It can’t be remediated elsewhere. The entire estuary at one time totaled several hundred acres. This is the only portion of the historic estuary that’s available for restoration.

Estuaries are one of nature’s perfect designs. Fresh water being lighter than salt water flows out on the surface drawing salt water in underneath, along with phytoplankton and zooplankton. This mixing is important and it happens best in shallow water in the presence of sunlight and atmospheric oxygen. In a darkened pipe there is no sunlight. No phytoplankton. No marine web of life. An intertidal culvert is especially bad because the tide pushes water back up into the pipe where it becomes septic. East Bay is Federally Degraded for low levels of dissolved oxygen and high levels of nitrates, conditions that would benefit from restoration.

East Bay is also contaminated with PCBs and dioxin. We should be attempting to locate, isolate and remediate the sources of this ongoing contamination. Southern Resident Orcas are probably heading toward extinction for two reasons, lack of food and the presence of lipophilic persistent bioaccumulative toxins like PCBs and dioxin.

Statewide, benthic levels of PCB and dioxin in urban, contaminated areas have not gone down. “PCBs in Puget Sound’s benthic indicator species appear to be increasing in several urbanized areas, and not decreasing in any sampled location. Particular challenges identified by these studies may be to develop methods for reducing new PCB sources to the pelagic food web and to understand the causes for PCB increases in benthic species from urbanized locations. Puget Sound’s pelagic prey base continues to be a hot-spot of PCBs in the northeastern Pacific Ocean region, resulting in long-term contamination of apex predators and other species important to healthy ecosystem function and to human use. Recovery of at least two species listed for protection and recovery by the U.S. Endangered Species Act and Canadian Species at Risk Act, southern resident killer whales (Krahn et al. 2002) and Chinook salmon (Myers et al. 1998) may be significantly hindered by their exposure to PCBs from their prey base in Puget Sound (Hickie et al. 2007; O’Neill and West 2009; Mongillo et al. 2016).”

Moxlie outfall 01.jpg
Moxlie Creek outfall into East Bay

According to the comprehensive Sediment Characterization Report of 2008 (page 54): “Additional evaluation is needed at the Hardel Mutual Plywood site and the Moxlie Creek discharge to determine whether these sites are significant sources of dioxin/furan contamination through the use of PCP as a wood preservative…” The way to do this is to sample using in-line sediment traps and similar techniques. If the Moxlie Creek discharge is the source of dioxin entering the bay, the most plausible source of dioxin entering the pipe would be contaminated fill around the pipe entering through fissures. Claiming that the source is an old piling or woody debris doesn’t rule out the culvert, even if true.

Ecology claims that they “collected and analyzed soil samples from borings to define the vertical extent of soil contamination (and) drilled as deep as we needed to, to define the vertical extent of soil contamination.” They claim that “if DNAPLs (dense non aqueous phase liquids like dioxin containing creosote) were present, we would see related contamination somewhere in the soil, vapor, and/or groundwater.”

According to the the EPA: “Although analysis of ground water provides useful information on the distribution of the soluble components of the DNAPL, the presence of other phases of the DNAPL may go unrecognized. The investigation must, therefore, be more detailed to obtain information concerning the phase distribution of the DNAPL at a site. Site characterization may require analyses on all four phases (aqueous, gaseous, solid, immiscible) to yield the appropriate information. In brief, data collected on the various phases must be compiled, evaluated and used to help identify: where the contaminant is presently located; where it has been” and so on.

The nature and extent of contamination on the Port Peninsula are unknowns. DNAPLs are heavier than water and will tend to sink to an impervious layer and migrate horizontally. We should sample to this impervious layer which on this property is about 25 feet deep.

Harry Branch