2cmorau
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Selenium, Mercury and Suction Dredging -- Studies Contradict California State Water Resources Board - Miner's News - ICMJ's Prospecting and Mining Journal
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There is no doubt that mercury and methyl mercury are hazardous substances when absorbed by humans through contact or when consumed within food in large quantities.
Federal and state regulatory agencies often cite mercury and methyl mercury in our waterways as a major factor for further restrictions on placer mining, and on suction gold dredge mining, in particular.
However, these regulatory agencies are minimizing selenium and its neutralizing effects.
In the Draft Subsequent Environmental Impact Report (DSEIR) on suction dredging published by the California Department of Fish and Wildlife in 2011, the agency calls the evidence of selenium neutralization “lacking” despite numerous studies to the contrary.
The DSEIR reads, “Evidence from laboratory experiments has shown that selenium may be able to moderate the toxic effects of Hg when present at a molar ratio greater than around 1:1, and that most fish in the United States contain high enough levels of selenium to make this a possibility. However, epidemiological support for this phenomenon is lacking, and the limited evidence gives mixed results.”
In contrast to the claims made by the California Department of Fish and Wildlife, numerous scientific studies have shown that selenium—a common element in soils and waterways—binds with mercury and methyl mercury to neutralize it.
Raymond and Ralston, in Mercury: selenium interactions and health implications, state, “Measuring the amount of mercury present in the environment or food sources may provide an inadequate reflection of the potential for health risks if the protective effects of selenium are not also considered. Selenium’s involvement is apparent throughout the mercury cycle, influencing its transport, biogeochemical exposure, bioavailability, toxicological consequences, and remediation.
“Likewise, numerous studies indicate that selenium, present in many foods (including fish), protects against mercury exposure. Studies have also shown mercury exposure reduces the activity of selenium dependent enzymes. While seemingly distinct, these concepts may actually be complementary perspectives of the mercury-selenium binding interaction. Owing to the extremely high affinity between mercury and selenium, selenium sequesters mercury and reduces its biological availability.”
Dr. TW Clarkson of the University of Rochester, New York, published a study on the effects of methyl mercury exposure after nearly fifty years of research. Clarkson concluded that consuming fish that contained typical mercury levels would have no adverse effects.
get this out to buds, spread the news
There is no doubt that mercury and methyl mercury are hazardous substances when absorbed by humans through contact or when consumed within food in large quantities.
Federal and state regulatory agencies often cite mercury and methyl mercury in our waterways as a major factor for further restrictions on placer mining, and on suction gold dredge mining, in particular.
However, these regulatory agencies are minimizing selenium and its neutralizing effects.
In the Draft Subsequent Environmental Impact Report (DSEIR) on suction dredging published by the California Department of Fish and Wildlife in 2011, the agency calls the evidence of selenium neutralization “lacking” despite numerous studies to the contrary.
The DSEIR reads, “Evidence from laboratory experiments has shown that selenium may be able to moderate the toxic effects of Hg when present at a molar ratio greater than around 1:1, and that most fish in the United States contain high enough levels of selenium to make this a possibility. However, epidemiological support for this phenomenon is lacking, and the limited evidence gives mixed results.”
In contrast to the claims made by the California Department of Fish and Wildlife, numerous scientific studies have shown that selenium—a common element in soils and waterways—binds with mercury and methyl mercury to neutralize it.
Raymond and Ralston, in Mercury: selenium interactions and health implications, state, “Measuring the amount of mercury present in the environment or food sources may provide an inadequate reflection of the potential for health risks if the protective effects of selenium are not also considered. Selenium’s involvement is apparent throughout the mercury cycle, influencing its transport, biogeochemical exposure, bioavailability, toxicological consequences, and remediation.
“Likewise, numerous studies indicate that selenium, present in many foods (including fish), protects against mercury exposure. Studies have also shown mercury exposure reduces the activity of selenium dependent enzymes. While seemingly distinct, these concepts may actually be complementary perspectives of the mercury-selenium binding interaction. Owing to the extremely high affinity between mercury and selenium, selenium sequesters mercury and reduces its biological availability.”
Dr. TW Clarkson of the University of Rochester, New York, published a study on the effects of methyl mercury exposure after nearly fifty years of research. Clarkson concluded that consuming fish that contained typical mercury levels would have no adverse effects.
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