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Post by stephan on Jan 17, 2019 0:22:25 GMT -5
Interesting. Why so much bad publicity about pesticides and herbicides then? Because they can b highly toxic. For example nicotine is used as an insecticide yet as little as 5mg can kill an adult human.
A common insecticide used back in the 50s was DDT, which has been linked to various cancers. Even though it was eventually banned we are still experiencing problems from DDT since it takes 100 years to break down in the soil and has entered the food chain concentrating mainly in predators.
And most herbicides are very powerful and stable xenoestrogens. These xenoestrogens can be up to hundreds of thousands more powerful that our own human estrogens and can last decades in the soil. As an example look at the compound Agent Orange, which was an herbicide/defoliant sprayed in Vietnam. It contains high levels of the powerful xenoestrogen dioxin linked to various cancers.
While nicotine IS highly toxic, it's not quite that toxic. The oral LD50 is estimated between 5-50mg/kg body weight.
There is also a huge difference between "old" and a lot of the "new" chemistry when it comes to "-cides" (insectices, fungicides...). While the suffix essentially means "killer," newer products tend to be a lot more specific to the target organism. That said, if you read the Safety Data Sheets, most of them are still toxic to aquatic life, and runoff needs to be avoided. However, products listed for "organic" use are not necessarily harmless. You can scan the OMRI (Organic Materials Review Institute) lists of approved chemicals, and cross-reference them with the Safety Data Sheet, and some still qualify as "hazardous" in states like California. At the same time, some completely benign substances are not approved. As both James and I have stated, it's complicated. And often political. And, unfortunately, some pseudo-science does enter. The whole anti-GMO blanket policy, of the organic movementfor instance, actually increases the use of chemicals by "conventional" growers who are one the fence.
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Post by stephan on Jan 17, 2019 0:45:46 GMT -5
Oh! One more thing: some "toxic" minerals are necessary for life. Check the label on a multi-vitamin/mineral sometime. While there's no lead or arsenic (unless it's made in China) it'll likely have copper, chromium, molybdenum, selenium and others. Too much of the essential minerals isn't good (even calcium or iron), but some amount is necessary. Life is very complex. I will have to see if I can find a sheet that I once had that listed all the "ingredients" for an apple. I'll post it if I do. It's pretty astounding. It is not just amount but also form. Trivalent chromium for example is essential to health as where hexavalent chromium is extremely toxic.
Yep, that was my point. You can't just tell from the presence of a mineral. Amount and form matter. Not just the oxidation state (like in chromium), but the counter-ion. Some mineral salts are practically insoluble and inert, while another for is highly poisonous.For example, Copper (II) chloride has an LD50 of >2000mg/kg (based on mouse testing, average adult human would have to ingest more than 140g, or 5oz for half of them to die -- and probably a lot more than that, that is just where they stopped testing). Copper sulfate, on the other hand has and LD50 of 482mg/kg -- at least four times lower. Again. Complicated.
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Post by vegasjames on Jan 17, 2019 2:20:12 GMT -5
Because they can b highly toxic. For example nicotine is used as an insecticide yet as little as 5mg can kill an adult human.
A common insecticide used back in the 50s was DDT, which has been linked to various cancers. Even though it was eventually banned we are still experiencing problems from DDT since it takes 100 years to break down in the soil and has entered the food chain concentrating mainly in predators.
And most herbicides are very powerful and stable xenoestrogens. These xenoestrogens can be up to hundreds of thousands more powerful that our own human estrogens and can last decades in the soil. As an example look at the compound Agent Orange, which was an herbicide/defoliant sprayed in Vietnam. It contains high levels of the powerful xenoestrogen dioxin linked to various cancers.
While nicotine IS highly toxic, it's not quite that toxic. The oral LD50 is estimated between 5-50mg/kg body weight. Lot less than that:
"The lethal dose of nicotine for adults has been known as 40-60 mg (0.5-1.0 mg/kg body weight). Fatalities have been reported from ingestion of 30g tobacco and 0.8 g of snuff."
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Post by arghvark on Jan 17, 2019 8:57:30 GMT -5
If you don't completely resolve the wheel or shaft balance issue and don't want to mess with mats, what about velcro "dots" at the corners of the base to hold it to the workbench?
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Post by Rockoonz on Jan 17, 2019 21:01:16 GMT -5
If you don't completely resolve the wheel or shaft balance issue and don't want to mess with mats, what about velcro "dots" at the corners of the base to hold it to the workbench? Dots a good idea...
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Post by arghvark on Jan 18, 2019 10:11:50 GMT -5
If you don't completely resolve the wheel or shaft balance issue and don't want to mess with mats, what about velcro "dots" at the corners of the base to hold it to the workbench? Dots a good idea... I see what you did there
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victor1941
fully equipped rock polisher
Member since November 2011
Posts: 1,978
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Post by victor1941 on Jan 18, 2019 22:35:21 GMT -5
I would try to tamp down the vibration as step one. I use a UV-18 vibe tumbler and have placed it on a table with a 1" wooden frame around the base to prevent it from walking off the table. The frame is nailed to a plywood shop table.
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