Document nmjdLabYeXm2dywR6OqaJVBnm

Metals focus shifts to cadmium AIthough it's a potentially hazardous pollutant and many questions remain to be answered, there will probably be no "cadmium crisisT g s -^ O Thu Japanese call it "itai-itai byo"--- the ouch-ouch disease--because of the excruciating pain accompanying a bi/.anu skeletal disorder known as osteo malacia. In liaise alllicicd with ilai- iini, lames may become so fragile that meie coughing is sollieienlly Irauinalic to tiacthreribx. I:or years in the altermalh ol World War II, larmcrs in Japan's Jintsu River Uasm. where itai-itai was most prevalent, hail complained that waste water from a zinc mine, dis charging diicclly into the river used for irrigating rice paddies, was spoil ing crops. But it wasn't until last year thai Okayama University's Jun Kobayashi established the common de nominator between the frequently fatal itai-itai and failing rice crops. The cul prit was cadmium--a metal inti mately associated with lead and zinc deposits and lung known to be harm ful to man. Although toxicologists now believe that various nutritional deficiencies play a critical role in the full-blown ilni-itiii syndrome, the discovery that imputations could he exposed to toxic quantities of cadmium by contami nated water caused a nation still jiltery over (lie mercury pollution of Minumula Bay to shudder anew at the prospect of yet another heavy metal disaster. And more than a little con cern was expressed in the U.S. Iasi year over finding: that showed many municipal water supplies contain sig nificantly more than the (I. I parts per million of cadmium considered to be "stile" for drinking. As with mercury, very little was known about the fate and distribution of cadmium in the environment. What wax known was scary enough. What was not known was even scarier. It was known, for example, that cadmium ho* a very long biological hidf-lile in man ami llicicfore lends to iiccmmdatc iu the laxly, lislimates ranged from 10-25 years,, compared with about 70 days for methyl mercury. It was also known from industrial toxicology that cad mium could cause severe liver and kidney damage, pulmonary disease, and death. In the absence of solid toxicological data, speculative analogies between mercury and cadmium were common. Was there, for example, a process sim ilar to the microbial mcihylation of mercury which would concentrate cadmium in the food chain? Fortu nately. that hypothesis appears to he incorrect. Nevertheless, disturbing questions about the amount of cad mium discharged into air and water and the clFcels ol chronic exposure to cadmium icnviiucd. In an clfurt to answer some ol those questions the Environmental Protec tion Agency (i-rx) commissioned studies to determine just how serious u threat cadmium poses. Although more work remains' (u be done, a pic ture is beginning to develop that is not quite so black as might have been imagined. The consensus of opinion is that although cadmium is a potentially dangerous pollutant, there is no rea son to believe that a "cadmium crisis'* is imminent. Cadmium- is not "an other mercury." i Distribution Cadmium is a relatively rare mci.il --the earth's crust contains .ut aseiage of only 0.5 ppm. It norms ,lnell\ as the sulfide, grecnockile, in various zinc, lead, and copper ores. Nearly all the cadmium produced m the world is a by-product of zinc smelting Re cycling is virtually nonexistent. Only 4% of Ihe 10.6 million pounds or cad mium produced in the U.S. during 1968 was derived from reprocessing cadmium-containing scrap. Cadmium does not degrade iu the environment. As greater quantities of cadmium are refined, more and more of it becomes available to interact with man. Domestic consumption of cad mium was mmc than IS million tons iu I960 (the last yem lot whu.li ulli- cial statistics are available) 'Hint's a whopping 13% jump over the figure for 1968. All indications point to fur ther sharp increases in consumption for Ihe foreseeable future. And be cause nearly ever) thing pi oduccJ by cudmilim-iising industries sooner or later winds up on the junk pile, the potential for environmental contami nation is considerable. Studies funded hy the eu s provide a fairly complete inventory of sources and amounts of cadmium emissions into the atmosphere. Parallel studies for cadmium in water supplies, how ever, aie lacking. Nearly 4 <> million pounds of cadmium was emitted into Ihe atmosphere in Ihe U.S. during according to a study piepared lot the National An I'oIJiiiion fmitiol Administration in 1970. I ce J. MoC'ahc, director ol Epidemiology and Biometrics for l n.vS Office of Water Programs says there's "some hut not much" cadmium in drinking water. Just litiw iniieli is discbarge,I into, waleiways is not known. By fur the largest single user of cadmium is the electroplating indus- N22895 0007-SWP-037390 ' ' Eouttds of cadmium emitted to atmosphere in U.S. in 1968' '-ilruriH cad mcbiilutgical processing . ( P.IOC/.SilO '**' mining . . .' ..*v.v Cd separation twin ora S30 - v'-:- .. // ' .2,100,000/ . ;. try- The mctul imparls an attractive, corrosion-resistant tinish to ferrous metals. Virtually no cadmium es capes into Ibe ulmosphcre from elec troplating operations; bow much gets into water from plating baths is any body's guess. Hopefully, says McCabe, such information will be forthcom ing in the next couple of years tis dis charge permits, required by the Army Corps of Engineers. arc processed (see "What's the U.S. Army doing in wa ter j n tlhiiii'ii control'.''' is*i, Dccetuhci IV7I). page 1101>. Other important applications for cadmium include pigments, plasties stabilizer*. alloys, and batteries. To gether with electroplating, these live product groups account for more than 90`r of the cadmium used domesti cally. wide variety of minor applica tions -- television picture luhc phosphors, fungicides for golf courses, con. (rot mb, anil shields in nudeur re actors. and curing agents for rubber, among others--accounts lur the re maining ') nr;. Emissions Mo m cadmium emissions into the atmosplierc full into two general cate gories- -disposal and metallurgical pro cessing. Disposal includes incinera tion aml recycling of ferrmis scrap and accounts for more than half (he cadmium pul into the air each year. The biggest chunk is lost in reclama tion of scrap steel and recovery of copper from automobile radiators. Incineration of plastic products--rang ing from Kittles to baby pants--also ailds cadmium to the atmosplierc. Metallurgical processing emits nearly as much cadmium to the air as disposal does. Although actual mining operations contribute only slightly to atmospheric cadmium levels, rousting and .sintering of ore release vast quan tities of cadmium into the air. Smaller Amounts of cadmium in the air come from a variety of manufac turing processes as well us the use of certain fertilizers, fungicides, motor oils, and ruhber tires. Against this backdrop of emissions data, r.i'A commissioned three Swedish veteran cadmium watchers from .Stockholm's Karolunka .Institute to prepare a report on the health effects of cadmium in the environment. The trio. I.ars Friberg, Magnus Piscnlor, and Cunnar Nordberg. recently pre sented the results of their review to a symposium at the University of Roch ester School of Medicine. The Swedish report says that al though the body contains only l/ig of cadmium t birth, a 50-year old, 70-fcg (1554b) "standard mao'* has a body burden 30,000 times that amount (30 mg). Excessive exposure to cadmium cun damage Ihc liver, kidneys, spleen, or thyroid, hut the amount of cadmium needed to pro duce severe damage is not known. Ambient air contains only a small amount of cadmium, the report says, hut in the vicinity of certain factor ies, concentrations can be much higher. Cadmium h absorbed cither by inhalation or ingestion und hu man beings arc exposed to substantial amounts in food, according to the re port. A differential absorption rule. however, -makes inlul.iliiui of cad mium more dangerous Ilian ingestion. Only about 5'V of ingested eailitiimu is uhsoihcd by the body: estimates for nhsoipiitMi of inhaled cadmium tun as high as 411'!!-, but aelual aumiiuls me piuhohU lower. Recent wink hv Hamid It I'etciiug af llie Univeisily ol Cincinnati indicates that people who smoke as few as 10 cigarettes per day --or the equivalent in other tobacco products - arc exposed to concciilrations of cadmium limn 10-100 times greater than those in the ambient air. Worse yet. smoke from smoldering to bacco that is not inhaled--the sidestream--contains more cadmium than (be mainstream inhaled by Ihc stnoket. Thus, everyone in the same room with a smoker is exposed to elevated cad mium levels. Cadmium has also been implicated in csirdiovasculur disorders and can cer. although the Swedish team em phasizes that there is no chucluxivc statistical evidence linking ladmittm with these diseases. Research needs The Fribcrg-Piscaior-Nurdberg re port lists several research priorities in- eluding: 'I he ` urgent ami immcdinle" need for experithents on ilose-icspmtse ic- lationships considering absorption and excretion rales, particle si/e. ami ex posure routes; Studies on concentration of cad- mium in various organs relative to total body burden; * Development of belter indicators of cadmium levels in Ihc body: Further work mi teratogenic or carcinogenic effects uf cadmium, both alone and in combination wiiii natu rally occurring chelating agents such as imra and n t a) *'Jlie dciinilinn ol iiK'cli.iMisms foi .`iccinuulalion in Inod chains; and * Mclalnilic studies establishing the rots* of essential trace metals in cad mium nccuimilaliun. Thcic is no douhl that cadmium has "caused tumble," according to Robert J. M. Horton, senior research advisor for i-pa's Air Programs Of- llcc. Division of Effects Research. Hut, he adds, "I cant think of any reason why tliere should he a panic reac tion." What stejw will he taken hy the i-pa to control cudmium remain uncertain, hat Fribeig offers some ad vice: "All >uch long half-life sub stances should lie controlled to the greatest extent possible." IIMM ViriiflivS, Nmilhcr V. Srirtrtnbrr IV7I 7S5 ; j I 1 I ! { I 0007-SWP-000118300