[Update 12/17: The Olympian has reported that the Department of Health has narrowed down the area which the geoduck with elevated levels of Paralytic Shellfish Toxins (PST) were harvested from. One is in Poverty Bay, located north of the old ASARCO plant. The actively harvested "Redondo" tract was closed in 5/31 due to elevated levels of PST (97) then reopened again 6/14. It was unknown whether elevated arsenic levels were found in this shipment, but in the 1997 NOAA report noted below the highest levels of Arsenic in sediments were found in core samples 5 and 6 (see graph in post below). As noted as recently as this month in the on-line version of Science of the Total Environment: "The American Smelting and Refining Company (ASARCO) smelter in Ruston, Washington, contaminated the south-central Puget Sound region with heavy metals, including arsenic and lead."]
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Is this geoduck something you'd want to eat?
The Chinese now say no.
Why so surprised?
The recent ban on importing shellfish harvested from Washington state due to elevated levels of Arsenic and paralytic shellfish toxins (PST) found in geoduck shipments should come as no surprise to agencies nor the industry. In fact, it is better to ask the question of why it took so long for the Chinese to get upset. Fingers pointing to whether the Chinese know how to test shellfish should also be directed to those agencies responsible for overseeing food safety in the United States and shellfish harvested from Puget Sound.
Measurements of Arsenic in Puget Sound Core Samples
from "Historical Trends in the
Accumulation of Chemicals in Puget Sound." (1997)
Measurements of Arsenic at various depths. Estimated year
accumulated on left, depth on right, level at the bottom.
p. 25 of NOAA Technical Memorandum
(click to enlarge)
Elevated levels of Arsenic in Puget Sound sediments is old news to NOAA
Since 1997 NOAA has been aware of elevated levels of Arsenic in Puget Sound's sediments, concentrated highest in those sediments north of the old ASARCO plant in Tacoma. Operating for almost 100 years, the once largest smokestack in the United States discharged arsenic, lead, and a variety of other chemicals into the air. From there the prevailing winds carried the discharge plume north over Puget Sound where the chemicals and metals gradually settled out of the air into the waters of Puget Sound and onto the adjacent lands where they sometimes remained, other times washed into the various bodies of water, both fresh and marine. Rainfall only hastened the deposits. As seen in the graphs above, over time sedimentation buried those deposits. But they did not go away, leaving the highest concentrations remaining in depths of 30 to 50 centimeters, or 1 to 2 feet undisturbed. Until geoduck harvesting began.
Commercial geoduck harvesting
from subtidal sediments.
Geoduck burrow into deeper sediments which, when harvested, overturn those sediments and reintroduce them to the water columnGeoduck are the largest burrowing clam in the world, burrowing into the sediments to depths of 3 feet. There they grow up to 7 pounds in weight. During harvest, a water jet is used to dislodge the sediments surrounding the geoduck from which it is pulled. As seen in the short video clip above, all sediments down to the depth of the geoduck are disturbed. When the geoduck is pulled out large amounts of sediment enter the water column, along with anything else they may happen to contain. From there they drift and settle, in some cases being taken in and absorbed by marine species in the area, such as geoduck. Through their indiscriminate filtering, metals and chemicals may be absorbed and retained, in turn taken in by those who may happen to eat parts in which they are retained.
Just because you don't see it
doesn't mean it's not there.
Who tests the sediments and how deeply are they tested? Oakland Bay's lesson
The Department of Ecology generally oversees sediment testing. However, testing is typically within the upper few centimeters, not deeper where past industrial activities may have resulted in higher discharges than currently taking place and where things may have settled, to be buried over time. In addition to the Arsenic found in the 1997 report to NOAA is what was found in the deeper sediments of Oakland Bay near Shelton. Currently producing the largest amount of Manila clams in the United States, the deeper sediments were found to contain elevated levels of Dioxins. Because Manila clams do not burrow as deeply as geoduck it is currently believed these Dioxins will remain in the deeper sediments. But it is an example of what lies below the surface.
Note: For a more current study on sediments and current concerns over increasing "non-point" pollution problems from urban runoff, read "Historical Inputs and Natural Recovery Rates for Heavy Metals and Organic Biomarkers in Puget Sound during the 20th Century".
Alexandrium cantenella, the
source of PSP toxins
Paralytic Shellfish Poisoning toxins and subtidal tract closures occur often, are occurring now, and is not something new
It should be clear from the number of subtidal tracts which close, open, and close again due to elevated levels of PST that Puget Sound is dynamic and testing for PST is critical. Through the past six months alone there have been over 15 subtidal tracts which were closed to harvesting due to elevated levels of paralytic shellfish poisoning toxins. Currently there are four active tracts closed.
Subtidal tracts closed due to
paralytic shellfish poisoning toxins
Since September 10, Wyckoff Shoal has
opened/closed numerous times
Timing is everything
The challenges of timing and testing are easily seen in tracts closed, opened and closed again. Seen above are two of the currently active subtidal tracts in south Puget Sound which are currently closed - Wyckoff Shoal and Fox Island South. Of importance is the number of times Wyckoff Shoal has been closed and reopened over the past 10 weeks. Closed 9/10, it was reopened again on 9/26. 10/2 it was closed again and reopened 10/29, only to be closed 12/4. Just east of Wyckoff shoals is Fox Island whose active tract was closed 9/13. While the above demonstrates testing is active, it more importantly demonstrates the dynamics of Alexandrium populations and the significance of missing one day, the result being geoduck with elevated levels of PSP toxins arriving in China. Of most significance is the closures/openings demonstrate there are active populations of Alexendrium blooming throughout Puget Sound (see table below for tracts which have been closed, some multiple times, due to elevated levels of PST). *For a map click here where you can enter the name of the tract to find the location.
Redondo (closed 5/31, opened 6/14); Lisabeulla (closed 6/14, opened 8/27, closed 11/18, opened 11/25); Protection Island (closed 6/25, opened 9/10, closed 10/14, opened 10/21); Manzanita (closed 7/1, opened 7/8, closed 9/16, opened 9/23, closed 9/30, opened 10/28, closed 11/12); Buck Bay (closed 7/23, opened 8/6); Siebert Creek (closed 8/12); Fox Island (closed 9/13); Agate Pass/Sandy Hook (closed 11/5); Indianola (closed 11/12, opened 11/19); Apple Cove (closed 12/9)
Testing for Alexendrium Cysts in Puget Sound
Alexandrium and PST no longer appears to be a warm water problem in Puget Sound
From the University of Washington on the Clifford A. Barnes and Alexandrium: We are working on mapping the distribution of Alexandrium catenella cysts in the surface sediments of Puget Sound. This dinoflagellate (type of phytoplankton) has a life cycle where it spends the winter months as a cyst in the sediment and then when conditions are right (warmer for instance) can germinate into the water column and reproduce. [click here for study site] Beyond the closures of subtidal tracts, the awareness of the problem which Puget Sound has regarding Alexandrium and PST is found further in the testing which the University of Washington is doing. Through use of the Cliffor A. Barnes, they are taking core samples throughout Puget Sound to try and determine population "seed beds" of the cysts from which Alexandrium blooms. What is not clear is whether the current closures of subtidal tracts during the colder months means that Alexandrium and PST are no longer a warm water problem.
Poaching and greed presents a problem for everyone, not just the Chinese
On top of the agency awareness of chemcials within the deeper sediments in which geoduck grow and the apparent year round problem which Alexandrium and PST are creating comes poaching. Driven by the unsustainable price of geoduck, based on only what the Chinese are willing to pay, comes greed to "grab what you can when you can." It is next to impossible to guarantee no wild geoduck are harvested illegally. It is too easy for divers to work under the cover of night, hidden in the fog of south Puget Sound, to harvest wild geoduck. Inaccurate reporting of harvest volumes allows poached geoduck to be claimed as legally harvested and exported, arriving on China's doorstep with elevated levels of Arsenic and PST. When tested and found, is it any wonder China questions who is doing what?
This bubble too shall pop
Whether it be the current situation or the elevated level of education making the Chinese population aware that geoduck are not the equivalent of Viagra, this bubble too shall pop. Left in its wake will be thousands of PVC used currently to grow intertidal, and perhaps soon subtidal geoduck. A few will have been made wealthy, able to walk away from long term leases and the mess left, leaving the taxpayer and tideland owners to clean up afterwards. Maybe some should be thanking China for bringing this to a head.
Who gets to clean up the mess?
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