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Volume 41 )ournal of Weather Modification 78 more bioavailabl io? de e1?'S °odifeactive Silver concentrations in ihe treated soils ranged Silver is . ?ow anion concentrations, from 37.2 to 44.5 N9/k9, compared with the con- lower sus- centrations in the control areas which range sulfide or sulfur containing ligands, low concen- trations of organic tigands (humatH )' strand and nom 30.4 to 6.7 N9/kg. pended sedirr?ent and lower PH (°9 ?g pri_ in aquatic environments W?, 1998), in soils and fresh water, Contamination bY silver al et al. (1997)• g condi- has been reviewed bY Fleg mary silver corr?Pounds under oxidizin I tions were believed to be chnditions the free and iodides. Under reducing nncipal s?cies 3.2 Air metal and silver sulflde are the p? Concentrations of silver in air have been reported (CICAD 44)• nom time to time. For example, silver concen ra- Recent published Work (gowles et al. 2002a) has e imPortant regulators tions in air near a smelter have been3 ?eatmos- shown that sulfides are v ry at 36.5 nglm3 and a level of 2.0 Ng/m pheric dust (CICAD 44)• Concentrations of up to of silver ion concentration, even under oxic con- m 0,075 mg/k9) A9 in dust collected ditions. 0.075 pp ( observed environments,ations increas- of over the SPERP tar9et ar ?as chave lea ?om th s work For brackish and marine by Kamber et al. (2009). ing salinity leads to increasing concentr silver-chlor m lexes because of the affinity of that silver travels great distances from its sourc . environ- o co P wn that levels of reactive sulflde The ievel of silver in the air inpOWen? hee silver ion for the ch4oride ion. Contemporary ments has been reported bY B research 1986) for has sho /m and the US in oxygenated naturai waters are stable and high ma It is worth reiterating that the h to ensure that siiver sulfde or silver tl?ieS 0?th 1? Bdtain 02 ??00j 1 to 0.001 Ng much higher enoug compiexes dominate (Bowles et al. 2002; °`^? ?evets allowed in air are ryP??I'Y doud- than levels reported in snow foNowing et al. 2002a; Bielmyer et al. 2002). seedin9 oPerations (Wa?urton et ai. 1995b, • Although they did not report silver levels in the Snowy Hydro Limited 2008). ocean generally, Martin et al. (1983) shon ed me able exposures in non- silver levels in the north-ea?oUkg (1.07 ox 10"? Estimating a?? ulations can be diffi- Pacific Ocean WefB ?. I P molikg at occupationaliy exPosed p°p mg/L) and increased with depth to 23 P cuit, as data or reco a? a??e ?,m 2440 m. it for sil- lacking. The US workP 3 NOHSC 1995). Sunda and H ??? aand1 b9ol?i?l reductono ver is 0.1g/m ( of 3,3 Silv r Concentrations in Snow that photochqg+ leads to a substantial decrease in biologica Sition of snow has also been uptake and toxicity. Redox conditions play a role • The me?? ?m? in determining bioavailability because the e{e- Studied in a number of environments inctuding mental form is unreactive towards ?f undlex for- that the US and the Mtarctic. For example, Warbur- mation. Adams and u??a {o ?thea ?e?l When ton et al. (1981) have examined trace metal lev- silver ( s not red els in snow in the Antarctic and concluded that Ag+) i complexed ta ligands for which it has a high affin- the silver founal? eached t1'?e same conclu- i? sources. TheY of levels of inetals in snow Tsiouns and co-workers (2?2) rep°?? °n ?e $ion following a study _ across the continental US. fol silver content of agricultural soits in GreeceS'n9 lowing a number of yeae ? so Is from? areas The natural background level of silver in snow in silver iodide. They survy the Snowy Mountains Main Range was deter- mined during the course of an earlier study on of Greece, one of some 8?1 and the o her some Mountains Council k g o f A g 1 had been apP ? A9i ha d b e e n a p- snow enhancement (Snowy T??y yev- plied, However the silver concentrations found in Meteorology wo??ng Grou p 1989). ,? p ? and the 100,000 soils ha from to the which 361 treated kg areas were within the e1s Were repo ?? to ? 5 n9/L (5x10" 9/ ) gengrally we?e ?ess than 2 ng/L. range found for the three control areas. - Scientific Papers -