Hi there. How is your day going? Me? For the most part it’s been a good day until I went out to look at my baby plants I’ve shared with you recently and found the same shiny silver dots all over their leaves after a rain like I’ve mentioned before that I noticed on our trees.
Well come to find out, for cloud seeding they use an material call silver iodide, which doesn’t completely dissolve in water! Is this the culprit?! The only way to know for sure would be a lab test of the plants which is worth considering! The last time we had an environmental lab test was for mold in our bathroom and it was almost $800! Ouch!
We had noticed this same material getting on our car windshield and our house windows for most of the 6 years we’ve lived here. Just this past year or so I noticed this shiny substance was showing up on the leaves of our plants and trees too. I wondered if it was bugs or slug trails or something else but they are too uniform in shape and form. Some of the dots were brown so I thought it was just artillery fungus at work but the dots on the brand new plants are clear and shiny. Are the cloud seedings spreading too much “seed” – are we drinking, eating and breathing this stuff? It wouldn’t be such a big deal if only a few places were engaged in this activity but it’s happening all over the world. This takes a small exposure to a major, long term exposure especially if they’ve been doing it since the late 1940’s!
Tell me, what’s the point of making rain so we have water if the water and everything that uses the water is poisoned?! Doesn’t make any sense at all to me!
It’s starting to get to the point I don’t even want to go outside or even let our dogs out for extended periods of time. I am concerned about my fellow citizens that work outside and are subjected to this environmental issue all day long, day after day – people with fossil fuel jobs, home construction, road construction, utility workers, our children who play outside at school and at home…play sports.
Am I blowing this out of proportion and making a big deal out of nothing…..no….my intuition tells me this is exactly what someone needs to do. An ordinary person like me who is paying attention to what’s going on in her world and trying to help her fellow world citizens….all of them….even the people flying the planes spreading this stuff all over. This world belongs to all of us!
Silver iodide is an inorganic compound with the formula AgI. The compound is a bright yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is highly photosensitive. This property is exploited in silver-based photography. Silver iodide is also used as an antiseptic and in cloud seeding.
From what I read from the pdf file I found from the Weather Modification folks, http://weathermodification.com/:
What are the environmental consequences of weather modification?
Environmental impact from cloud seeding operations can be broken into two categories:
##The effects of the chemical seeding agents used for the programs
##The impacts of precipitation changes
Environmental Impact from Cloud Seeding Agents
The active ingredient in cold cloud seeding agents is silver iodide, or AgI. Unlike ionic silver, the silver iodide compound is very stable, essentially inert. Numerous studies have been conducted that clearly demonstrate its safety. Even projects operated for decades have experienced no adverse environmental impacts because of silver iodide. Additional information about the safety of silver iodide, is found in many studies and reports. The active ingredient in warm cloud seeding is simple salt, either sodium chloride (NaCl, table salt), or calcium chloride (CaCl). Both are found abundantly in the environment; sea spray releases millions of tons of NaCl into the atmosphere annually.
Environmental Impact of Precipitation Changes
The effects of cloud seeding on precipitation are typically on the order of 10%, while seasonal natural variability may be as much as a factor of two. When viewed in this context, the seasonal effects resulting from increased precipitation are negligible.
[… POSITION STATEMENT ON THE ENVIRONMENTAL IMPACT OF USING SILVER IODIDE AS A CLOUD SEEDING AGENT JULY 2009 … Silver iodide, as used in cloud seeding, …
Silver Iodide Toxicity – Weather Modification Association
http://www.weathermodification.org/images/AGI_toxicity.pdf – you can download it yourself here
… POSITION STATEMENT ON THE ENVIRONMENTAL IMPACT OF USING SILVER IODIDE AS A CLOUD SEEDING AGENT JULY 2009 … Silver iodide, as used in cloud seeding, …
WEATHER MODIFICATION ASSOCIATION (WMA) POSITION STATEMENT ON THE ENVIRONMENTAL IMPACT OF USING SILVER IODIDE AS A CLOUD SEEDING AGENT JULY 2009
The Weather Modification Association (WMA) is occasionally asked to comment on questions regarding the environmental effects of silver iodide aerosols used in cloud seeding, which include silver iodide aerosol complexes such as silver iodide-silver chloride. Silver iodide is the primary component of silver iodide-based ice-nucleating complexes used in cloud seeding, and all these complexes will be referred to as silver iodide (AgI) in this statement. The published scientific literature clearly shows no environmentally harmful effects arising from cloud seeding with silver iodide aerosols have been observed; nor would they be expected to occur. Based on this work, the WMA finds that silver iodide is environmentally safe as it is currently being dispensed during cloud seeding programs.
Silver and chemical compounds containing silver are used by various industries and small portions of this silver are emitted into the environment as a process waste product. Industrial sources were much larger in the past than they are today; notable sources include silver emissions from the photographic and electrochemical plating industries, urban refuse, sewage treatment plants, specialty metal alloy production and electrical components. In 1978 an estimated 2,740 metric tons (metric ton = 1,000 kg) of silver were released into the US environment. This led the US Health Services and EPA to conduct studies regarding the potential for environmental and human health hazards related to silver. These agencies and other state agencies applied the Clean Water Act of 1977 and 1987 to establish regulations on this type of pollution. Standards were established for industry and laboratory disposal practices of drain water into sewer systems, safe silver limits in the public water supply, and thresholds of adverse effects of silver on the biosphere. In 1978 cloud seeding activities were the source of about three metric tons of silver (as silver iodide) released into the environment, or about 0.1 per cent of the total (Eisler 1996). About the same amount of silver iodide is being used annually for cloud seeding activities in the U.S. and Canada today. Cloud seeding activities release silver iodide to the atmosphere over specific areas of the western states of the U.S., Canada and some other areas around the globe to augment rainfall, augment snowfall or reduce hail damage. Environmental impact studies related to silver iodide usage in cloud seeding were conducted starting in the 1960s and continue to be conducted today; all findings to date indicate no adverse environmental and human health impacts (ASCE 2004, 2006; WMA 2005; WMO 2007).
How much silver is released into the environment by cloud seeding?
Silver iodide is usually sold by commercial chemical company distributors in granular or powder form. It is used in combination with various other chemicals, most often salts, and has been used for half a century as a glaciogenic agent (microscopic sized particles, referred to as ice nuclei, ice forming nuclei, or occasionally freezing nuclei, that spawn ice crystal formation). Silver Iodide is considered water insoluble (solubility constant at 10-9 g[of Ag] g-1 [of solventwater]; see units note), which means that if one gram of the chemical is added to one gram of water, roughly one billionth of that gram of silver iodide would dissolve in to the water; the remainder will stay in the water undissolved. This property allows the silver iodide particles to maintain their structure prior to contact with supercooled (colder than freezing) cloud droplets. Silver iodide, as used in cloud seeding, is either dissolved in a flammable solution or combined with other flammable solids to produce seeding flares or other devices, which are burned to release submicron-sized, virtually invisible, silver iodide aerosol complexes into the atmosphere. These complexes are plentiful in number and increase the probability of ice crystals forming when they reach cloud environments at temperatures near or colder than the AgI ice nucleation (or crystallization) temperature threshold (about -5°C).
This is significantly warmer than the threshold of most naturally occurring ice-forming nuclei, which commonly have thresholds near 15°C and colder. Only small quantities of seeding material are released from individual cloud seeding generators typically in the range of 5-25 grams of silver iodide per hour from ground generators and up to a few kilograms per hour from aircraft depending on the size of the target area. Moreover, this is being done only during certain periods and locations of precipitation-producing weather systems. The reason that such small quantities can be used is that AgI dispensing systems generally produce up to 1015 (see power of 10’s note) ice forming nuclei per gram of AgI expended (e.g., ASCE 2004, 2006). This means small amounts of AgI seeding material can produce tremendous numbers of ice crystal seeds that can create ice crystals, which can grow into snowflakes. The insolubility of AgI is a crucial factor for such small particles that allows them to maintain their identity (structure) intact and not condense water (and thus lose their structure) inside a cloud droplet. Without this property there would be no cloud seeding effect. As a metric of cloud seeding chemicals, silver concentrations have been measured in the snowpack of several cloud seeding target areas in the western U. S. The average concentrations throughout the snowpack have generally ranged from 4-20 x 10-12 g[of Ag] g-1[of solvent-water], rarely exceeding 100.0 x 10-12 g g-1 (Warburton et al. 1995a,b, 1996; McGurty 1999). Since seeding clouds could lead to rain (if snowflakes melt during their fall to earth) measurements of seeding chemical concentrations in the rainwater have also been done and found to be in similarly low concentrations (e.g., Sanchez et al. 1999).
Why is there concern about using silver iodide in cloud seeding?
It is well established that silver in some forms can be toxic to lower organisms without being toxic to higher animals (Kotrba 1968). Numerous controlled laboratory studies have shown that silver, silver nitrate and even silver iodide when added to laboratory aquariums, even at trace levels, can be toxic to some fish and other aquatic life when exposed over long time periods; the toxicity is related to specific compounds, concentrations and other factors such as water hardness, etc (e.g., Davies & Goettl 1978). However, these laboratory conditions bear little resemblance to outdoor freshwater bodies where the mobility of any of these silver compounds is essentially zero and these compounds are rapidly converted to less toxic compounds by the presence of other chemicals found in nature. Hence, they are not freely bio-available to the environment. Laboratory results derived from biological studies cannot be taken to imply any meaningful information about silver iodide used in cloud seeding because its insoluble nature makes it nearly impossible to dissociate sufficiently or rapidly enough to ever achieve toxic levels. Meaningful evaluation must include the specifics of the chemical form of silver (i.e., ionic silver, silver nitrate, silver iodide), the quantities involved, and the chemical, even physical, nature of the environment. Hence, care must be taken when comparing the potential impact of silver iodide on the environment as used in cloud seeding programs with the impact of silver or soluble silver in laboratory settings, which are not representative of the natural environment where cloud seeding is conducted.
Basis for asserting that cloud seeding using silver iodide has negligible environmental impact.
The potential environmental impacts of cloud seeding programs using silver iodide have been studied since the 1960s. These studies have all concluded that ice-nucleating agents, specifically silver iodide as used in cloud seeding, represent a negligible environmental hazard, (i.e., findings of no significant effects on plants and animals), (e.g., Cooper & Jolly 1970; Howell 1977; Klein 1978; Dennis 1980; Harris 1981; Todd & Howell 1985; Berg 1988; Reinking et al. 1995; Eliopoulos & Mourelatos 1998; Ouzounidou & Constantinidou 1999; Di Toro et al. 2001; Bianchini et al. 2002; Tsiouris et al. 2002a; Tsiouris et al. 2002b; Christodoulou et al. 2004; Edwards et al. 2005; Keyes et al. 2006; Williams & Denholm 2009). The U.S. Public Health Service established a concentration limit of 50 micrograms of silver per liter of water in public water supply to protect human health (e.g., Erdreich et al. 1985). The concentrations of silver potentially introduced by modern cloud seeding efforts are significantly less than this level. The literature embodies tens of thousands of samples collected from cloud seeding program areas over a thirty-year period showing the average concentration of silver in rainwater, snow and surface water samples is typically less than 0.01 micrograms per liter. More importantly, these measurements represent the total amount of silver contained in any given sample and are not specific to the form of silver present in a sample. Nevertheless, these measurements show that silver is virtually undetectable in any form in the vast majority of the tens of thousands of samples collected from these areas. More than 100 Sierra Nevada lakes and rivers have been studied since the 1980’s (e.g., Stone 1986); no detectable silver above the natural background was found in seeded target area water bodies, precipitation and lake sediment samples, nor any evidence of silver accumulation after more than fifty years of continuous seeding operations (Stone 1995; Stone 2006). Many of these alpine lakes have virtually no buffering capacity, making them extremely susceptible to the effects of acidification and sensitive to changes in trace metal chemistry. Therefore studies were conducted as part of environmental monitoring efforts to determine if cloud seeding was impacting these lakes. No evidence was found that silver from seeding operations was detectable above the background level. There was also no evidence of an impact on lake water chemistry, which is consistent with the insoluble nature and long times required to mobilize any silver iodide released over these watersheds. Comparisons of silver with other naturally occurring trace metals measured in lake and sediment samples collected from the Mokelumne watershed in the Sierra Nevada indicate that the silver was of natural origin (Stone 2006). Similarly, Sanchez et al. (1999) analyzed the chemistry of water bodies and rainwater from samples collected during a summer cloud seeding program in Spain, and determined the silver input from cloud seeding to be indistinguishable from natural inputs. Greek scientists studying the effects on soils, plants and their physiology, atmospheric precipitation, plankton, animals and man, as well as the impact of irrigation and organic matter to AgI leaching from the Greek cloud seeding activities found similar results following the analyses of 2500 soil samples (e.g., Tsiouris et al. 2002a; Tsiouris et al. 2002b).
The published scientific literature clearly shows no environmentally harmful effects arising from cloud seeding with silver iodide aerosols have been observed, nor would be expected to occur. Based on this work, the WMA finds that silver iodide is environmentally safe as it is currently being used in the conduct of cloud seeding programs.
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Ouzounidou G., H.-I.A. Constantinidou (1999). Changes in growth and physiology of tobacco and cotton under Ag exposure and recovery. Are they of direct or indirect nature? Arch. Environ. Contam. Toxicol., 37, 480-487. Reinking, R.F., N.H. Berg, B.C. Farhar, O.H. Foehner (1995). “Economic, Environ-mental, and Societal Aspects of Precipitation Enhancement by Cloud Seeding,” Manual 81, Guidelines for Cloud Seeding to Augment Precipitation, ASCE, Reston, VA, 9-47. Sánchez, J. L., J. Dessens, J.L. Marcos, J.T. Fernández (1999). Comparison of rain-water silver concentrations from seeded and non-seeded days in Leon (Spain). J. Weather Mod., 31, 87-90. Stone, R.H. (1986). “Sierra Lakes Chemistry Study.” Final Report to Southern California Edison Co., Contract No. C2755903. Stone, R.H., K. Smith-Miller, P. Neeley (1995). Mokelumne Watershed Lake Water and Sediment Silver Survey. Final Report to the Pacific Gas and Electric Company, Technical and Ecological Services, San Ramon, Ca. Stone, R.H. (2006). “2006 Mokelumne Watershed Lake Water and Sediment Survey.” Final Report to the Pacific Gas and Electric Company, Technical and Ecological Services, San Ramon, Ca. Todd, C.J., W.E. Howell (1985). “Weather Modification”. In Handbook of Applied Meteorology, David D. Houghton, Editor, John Wiley and Sons, Chapter 38, 1065-1139. Tsiouris E.S., A.F. Aravanopoulos, N.L. Papadoyiannis, K.M. Sofoniou, N. Polyzopoulos, M.M. Christodoulou, F.V. Samanidou, A.G. Zachariadis, H.-I.A. Constantinidou (2002α). Soil Silver Content of Agricultural Areas Subjected to Cloud Seeding with Silver Iodide. Fresenius Environmental Bulletin, 11, 697-702. Tsiouris E.S., A.F. Aravanopoulos, N.L. Papadoyiannis, K.M. Sofoniou, F.V. Samanidou, A.G. Zachariadis, H.-I.A. Constantinidou (2002b). Soil Silver Mobility in Areas Subjected to Cloud Seeding with AgI. Fresenius Environmental Bulletin, 12, 1059-1063. Warburton, J.A., L.G. Young, R.H. Stone (1995a). Assessment of seeding effects in snowpack augmentation programs: Ice nucleation and scavenging of seeding aerosols. J. Appl. Meteor., 34, 121-130. Warburton, J.A., R.H. Stone, B.L. Marler (1995b). How the transport and dispersion of AgI aerosols may affect detectability of seeding effects by statistical methods. J. Appl. Meteor., 34, 1929-1941. Warburton, J.A., S.K. Chai, R.H. Stone, L.G. Young (1996). The assessment of snowpack enhancement by silver iodide cloud-seeding using the physics and chemistry of the snowfall. J. Weather Mod., 28, 19-28. Weather Modification Association (2005). “Weather Modification Association Capability Statement.” WMA; http://www.weathermodification.org/capabilities.htm. Williams, B.D., J.A. Denholm (2009). Assessment of the Environmental Toxicity of Silver Iodide-With Reference to a Cloud Seeding Trial in the Snowy Mountains of Australia. . J. Weather Mod., 41, 75-96. World Health Organization (2002). “Concise International Chemical Document 44 (CICAD44): Silver and silver compounds: Envionmental Aspects.” WHO; http://www.inchem.org/documents/ cicads/cicads/cicad44.htm World Meteorological Organization (2007). “WMO Statement on Weather Modification.” WMO; http://www.wmo.int/pages/prog/arep/wmp/documents/WM_statement_guidelines_approved.pdf. NOTES: Following are intended to help non-technically trained readers understand information provided above. Power of 10’s note: Very large and very small numbers are often expressed in scientific or powers of 10 notation. The 1015 stated in the WMA statement means that 1 is 10 multiplied by 10, 15 times and it equals 1,000,000,000,000,000. When 10 is raised to a negative power it means 1 divided by 10 the power number of times; for example, 1 x 10-1 equals 0.1. Units note: g g-1 as used here means grams of chemical divided by grams of water in the sample, so that 1 x 10-12 g g-1 means 0.000000000001 grams of silver per 1.0 grams of water.