The estimated acute lethal dose of silver nitrate is at least 10 gm
The only known clinical picture of chronic silver intoxication is that of Argyria, a condition in which silver is deposed on skin and hair, and in various organs following occupational or iatrogenic exposure to metallic silver and its compounds, or the misuse of silver preparations.
Pigmentation of the eye is considered the first sign of generalized argyria.
Striking discoloration, which occurs particularly in areas of the skin exposed to light, is attributed to the photochemical reduction of silver in the accumulated silver compounds, mainly silver sulfide.
Melanin production has also been stimulated in some cases.
It is difficult to determine the lowest dose that may lead to the development of argyria.
A patient who developed a grey pigmentation in the face and on the neck after taking an unknown number of anti-smoking pills containing silver ethanoate was found to have a total body silver content of 6.4 ± 2 g.
It has been reported that intravenous administration of only 4.1 g of silver arsphenamine (about 0.6 g of silver) can lead to argyria.
Other investigators concluded that the lowest intravenous dose of silver arsphenamine causing argyria in syphilis patients was 6.3 g (about 0.9 g of silver).
It should be noted that syphilis patients suffering from argyria were often already in a bad state of health and had been treated with bismuth, mercury, or arsphenamine in addition to silver.
SAFETY OF NANOSILVER
Silver has been used for generations in goblets, silverware, and other food areas because of the belief that it inhibits diseases.
In more recent times, the former Soviet Union used silver to sterilize recycled water on their space shuttles.
Many international airlines use silver water filters to ensure safe drinking water for passengers.
The Swiss have approved use of these filters in homes and offices.
Some US city municipalities use silver in treatment of sewage and is sometimes used to purify swimming pool water to avoid the stinging of the eyes that chlorine causes.
CIS countries also purifies drinking water with nano-silver.
Silver has become the latest agent in the fight against airborne toxins, as well other industrial poisons, in the Japanese work place.
Each EPA approved product is required to have safety information, and according to that information a toxic spill or EPA reportable spill amount is required to be printed in the product MSDS sheet (Material Safety Data Sheet).
For example, a chlorine-type cleaning product (found for open purchase on store shelves right now) has a toxic spill rating of about three gallons, meaning that a spill of three gallons or more must be reported to the EPA and handled by HAZMAT authorities.
In comparison, American Biotech Labs™ 32 ppm nano-silver product has a toxic spill rating of 12,500,000 gallons.
An oil tanker will hold about a million gallons, which means that 12.5 oil tankers full of the ASAP nano silver disinfectant would have to spill their entire loads of the product together to be deemed a toxic event to the environment.
The management of American Biotech Labs believes that there is no tank or vat large enough in the entire world that could hold and subsequently spill enough of the ASAP disinfectant product to actually be reportable as a toxic spill to the environment.
In other words, nano-silver disinfectant product is perhaps the safest disinfectant product, for environmental reasons, ever approved to kill bacteria, mold, yeast and other pathogens.
Numerous ingested toxicity studies have been completed on nano-silver products.
Some of the studies are outlined below:
Independent LD-50 tests on animals at levels equivalent to approximately 200 times the normal internal use adult dosage were found to be non-toxic to the animals.
A 28-day bird flu study completed by a U.S. NIH virology lab also included a toxicity study in which the animals were fed levels of the nano-silver at 10-200 times the normal dosage daily. The ASAP nano-silver products were found to be non-toxic to the animals in the long term study.
A separate medical college study tested the ingestion of nano-silver product in animals at levels of 0.5 ml, 1.0 ml, and 1.5 ml daily for 28 days, and again found the product completely non-toxic to the animals.
An Indian (WHO approved) lab tested the ASAP nano-silver products for toxicity in a mouse-model study at levels of 50, 500, 5,000 mg/kg.The product was again found to be completely non-toxic to the animals at all levels tested in the Indian study.
A peer-reviewed preliminary HIV Human study found that the oral ingestion of 2 ounces daily for four months of the 10 ppm ASAP nano-silver product, had no negative effect on the seven human patients.
A U.S. Congressional Testimony outlines the use of the ASAP nano-silver product at between 0.5-1.0 ounce daily use at 10 ppm, for human use of the product against malaria and other human ailments (120+ cases).
In all cases, no negative effects were reported from any of the four hospitals and clinics that tested the product, by either external or internal use (mostly internal use).
The silver level is well below 180 micrograms / person / day permitted by W.H.O.
Hence it is safe for human as well as aquatic and terrestrial animal life.
Dr.Henry Crooks (Use of Colloids in Health-Disease) found that silver in the colloidal state is highly germicidal, quite harmless to humans and absolutely non-toxic.
Dr. Becker's experiments conclude that silver works on the full spectrum of pathogens without any side effects or damage to any part of the body.
Silver occurs in soil mainly in the form of its insoluble and therefore immobile chloride or sulfide.
As long as the sulfide is not oxidized to the sulfate, its mobility and ability to contaminate the aquatic environment are negligible. Silver in river water is "dissolved" by complexation with chloride and humic matter.
The detection limit of the spectrographic and colorimetric method with dithizone is 10 μg of silver per litre for a 20-ml sample.
The detection limit of atomic absorption spectroscopy (graphite furnace) is 2 μg of silver per litre, and of neutron activation analysis, 2 ng of silver per litre .
ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
Ambient air concentrations of silver are in the low nanogram per cubic metre range.
Average silver concentrations in natural waters are 0.2–0.3 μg/litre.
Silver levels in drinking water in the USA that had not been treated with silver for disinfection purposes varied between “non-detectable” and 5 μg /litre.
In a survey of Canadian tapwater, only 0.1% of the samples contained more than 1–5 ng of silver per litre.
Water treated with silver may have levels of 50 μg /litre or higher; most of the silver will be present as nondissociated silver chloride.
Most foods contain traces of silver in the 10–100 μg /kg range .
Estimated total exposure and relative contribution of drinking-water
The median daily intake of silver from 84 self-selected diets, including drinking-water, was 7.1 μg.
Higher figures have been reported in the past, ranging from 20 to 80 μg of silver per day.
The relative contribution of drinking-water is usually very low.
Where silver salts are used as bacteriostatic agents, however, the daily intake of silver from drinking-water can constitute the major route of oral exposure.
KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS
Silver may be absorbed via the gastrointestinal tract, lungs, mucous membranes, and skin lesions.
The absorption rate of colloidal silver after oral application can be as high as 5%.
Most of the silver transported in blood is bound to globulins.
In tissues, it is present in the cytosolic fraction, bound to metallothionein.
Silver is stored mainly in liver and skin and in smaller amounts in other organs.
The biological half-life in humans (liver) ranges from several to 50 days.
The liver plays a decisive role in silver excretion, most of what is absorbed being excreted with the bile in the faeces.
In mice, rats, monkeys, and dogs, cumulative excretion was in the range 90–99%.
Silver retention was about 10% in the dog, <5% in the monkey, and <1% in rodents. In humans, under normal conditions of daily silver exposure, retention rates between 0 and 10% have been observed.
EFFECTS ON LABORATORY ANIMALS AND IN VITRO TEST SYSTEMS
Oral LD50 values between 50 and 100 mg/kg of body weight have been observed for different silver salts in mice.
Hypoactive behaviour was observed in mice that had received 4.5 mg of silver per kg of body weight per day for 125 days.
After 218 days of exposure, albino rats receiving approximately 60 mg of silver per kg of body weight per day via their drinking-water exhibited a slight greyish pigmentation of the eyes, which later intensified.
Increased pigmentation of different organs, including the eye, was also observed in Osborne-Mendel rats after lifetime exposure to the same dose.
Antagonistic effects between silver and selenium, involving the selenium-containing enzyme glutathione peroxidase, were observed in Holtzman rats.
Mutagenicity and related end-points
In the rec-assay with Bacillus subtilis, there were no indications that silver chloride was mutagenic.
Reverse mutations in Escherichia coli were not induced by silver nitrate.
In the DNA repair test with cultivated rat hepatocytes, silver nitrate solution was positive only at a moderately toxic concentration.
Silver nitrate increased the transformation rate of SA7-infected embryonic cells of Syrian hamsters.
Silver dust suspended in trioctanoin injected intramuscularly in Fischer 344 rats of both sexes was not carcinogenic.