[env-trinity] Proposed Suction Dredging Regs

Brian Hill bhill at igc.org
Fri Mar 9 07:50:30 PST 2012


Thank you Glen for the documentation and very clear explanation.  This is the first documentation I have seen regarding mercury and suction dredging.  I hope the suction dredging community will spend time studying these reports, because, if the reports confirm the news article you reference, then it seems that suction dredging is a threat to waterways as suction dredge technology exists today.  I will forward your information to the dredging community.

 

Brian Hill

 

From: FISH1IFR at aol.com [mailto:FISH1IFR at aol.com] 
Sent: Thursday, March 08, 2012 7:14 PM
To: bhill at igc.org; env-trinity at mailman.dcn.org
Subject: Re: [env-trinity] Proposed Suction Dredging Regs 

 

In a message dated 3/8/2012 6:33:06 P.M. Pacific Standard Time, bhill at igc.org writes:

Suction dredges are designed to remove heavy metals, esp., gold and platinum, from waterways.  Because mercury and lead are almost as heavy as gold, suction dredges REMOVE mercury and lead from waterways along with gold and other heavy metals.  This blatant fact known to every dredge miner is carefully circumvented by those opposed to small stream miners.

 

Doesn't it make sense that removing mercury from waterways improves the health of the waterway?

 

A test of whether dredging stirs up or removes mercury from waterways would be very simple to demostrate.

 

Brian Hill

Brian....

 

I know the above in an "article of faith" for suction dredge miners, and one of their great defensive talking points, but it is also dead wrong on the science.  While the dredge might catch some otherwise dormant and sequestered subsurface mercury, it also stirs it up and methylates the rest (and likely a lot more than it catches), thus creating the most water soluble (and toxic to humans and fish) chemical compounds of mercury known.  

 

See, for instance, the USGS study Mercury contamination in California’s South Yuba River, available at:   <http://www.usgs.gov/newsroom/article.asp?ID=2686> http://www.usgs.gov/newsroom/article.asp?ID=2686

 

In short, the tests have been done, in many streams under varying conditions, and the conclusion is inescapable that suction dredging releases otherwise sequestered river bottom mercury that constitutes a human as well as fish health hazard.  And this is quite aside for any other adverse impacts, which also occur (increased sediments, disturbing or destroying intra-gravel eggs, disrupting noises affecting fish behavior, etc.).  All these suction dredge impacts are well documented.  In fact, CDFG did a good literature search of the scientific literature showing these various impacts, which is included as Appendix D to the Draft EIR and (for those hardy souls who like to see the source of such assertions) is attached.  

 

There is thus every good reason, both for environmental and human health reasons, to minimize suction dredge impacts in many California streams, and in many others to ban it altogether.  

 

======================================
Glen H. Spain, Northwest Regional Director
Pacific Coast Federation of Fishermen's Associations (PCFFA)
PO Box 11170, Eugene, OR 97440-3370
Office: (541)689-2000 Fax: (541)689-2500
Web Home Page: www.pcffa.org <http://www.pcffa.org/> 
Email: fish1ifr at aol.com

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