Document zQDvgxq7aZnykGxpKRRreDBBa

P x^ ^ y A Wire Reclamation Incinerator as a Source of Environmental Contamination with Tetrachlorodibenzo-p-dioxins and Tetrachlorodibenzofurans D A N IEL O. H R Y H O R C Z U K , M.D. University of Illinois School of Public Health and Section of Occupational Medicine Cook County Hospital Chicago, Illinois W ILLIAM A. WITHROW Illinois Pollution Control Board Chicago, Illinois C A R O L Y N S. H ESSE, M.S. United States Environmental Protection Agency Chicago, Illinois V A L R. B E A S L E Y , D.V.M. College of Veterinary Medicine University of Illinois Urbana, Illinois A B S T R A C T , The authors investigated an outbreak of un usual illnesses in humans and horses residing within 1.3 km of a wire reclamation incinerator. The study included site visits; medical and veterinary examinations;analyses of fur nace ash, fly ash, soil, and biologic samples for air residues. Tctrachlorodibcnzo-p-dioxins (TC D D s) and tetrachlorodibenzofurans (T C D Fs) were discovered in furnace ash, fly ash, soil, horse fat, and horse liver samples. IN C IN E R A T IO N is a commonly used method for the recovery of metals from wire scrap. The combustible por tion of wire insulation can be comprised of a wide variety ol materials, including rubber, paper, cotton, asphaltimpregnated fabrics, silk, and a large variety of plastics, such .is polyethylene, polypropylene, and polyvinyl chlor ide.' Older cables can contain chlorinated naphthalenes and polychlorinated biphenyls.2 'thermal degradation of insula ted electrical wirc_withnui proper air pollution control equipment can lead to the emission ul p jriiiu la ics, hydro carbons, metals, halides, carbon monoxide, nitrogen oxides, and sulfur o xides.I ,J Recent studies have shown that highly toxic polychlor inated dihen/o-p-dioxins (PCODs) and polychlorinated dibenzofurans (PCD Fs) can be emitted by municipal and industrial incinerators, fossil-fueled power plants, and indus trial heating facilities. 0 !ie 4 identified several PCDDs and PCDFs in samples of fly ash from three municipal inciner ators in the Netherlands. Buser and Bosshardt5 determined that the total concentrations o f PCDDs and PCDFs in fly ash from a Swiss municipal incinerator were 0.2 parts per million (ppm) and t). I ppm, lesp euively; the total concen trations of PCDDs and PCD Fs in fly ash from an industrial healing facility were 0.6 ppm and 0.3 ppm, respectively. Dow6 found PCDDs in parts per billion (ppb) levels in par ticulate matter from the air emissions of a stationary tar burner, rotary kiln incinerator, and a fossil-fueled power house. Kimble and Gross*1 found no tctrachlorodibcnzo-pdioxins (TCDDs) in l ly ash collected from the suck of a commercial coal-fired power plant, whereas Tiernan el al.' detected TCDDs in emissions from a municipal incinerator. The origin of PCDDs and PCD Fs in the airborne particulates from these combustion processes is still unclear. Recent studies'^IJ have shown that chlorinated phenols, polychlor inated biphenyls, chlorinated diphcnvl ethers, and chloruhen/encs can convert to PCPO s and P C D Fs in theim.il processes. A s insulated electrical wire and cable may contain some of these precursors, incineration of these maieiials might lead to the formation and emission of PCDIA and PCDFs. Our investigation of an outbreak of unusual illnes ses in humans and horses residing within 1.3 km of a wire redani.ruun incinerator included analyses of lurnacc .1>h, 1ly ash, soil, and horse lal and livci samples tor K 'M U s .iih I leirachlurudthenznfur.ms (TCD Fs). Description of [lie Incident from 1976 to 1980, citizens of a rural, midwestern com munity filed numerous complaints with their state Environ mental Protection Agency regarding a wire reclamation facility located within 1.3 km of their homes. They claimed ili.it incinerators at the facility weie Continuously emitting dense, malodorous smoke which they believed posed a haz ard to their health and property. The complaints were sup ported by photographs and a daily emission log kepi by one of the citizens. Several complained of burning eyes, sore throat. hcadachcr dizziness, and nausea temporally related to the emissions. The proprietor of a horse boarding stable and riding school staled that from 1976 to 1980, fourteen of her horses had died of unexplained causes. The affected hor ses suffered chronic weight loss, hair loss, and thickened kin mi the dori.il aspect of their bodies; some developed paresis in the rear and edema ol the distal parts o f the limbs. Horses which grazed in the adjacent pasture were the most severely affected. The wire reclamation facility incinerated wire, cable, and X-ray Him to recover copper, silver, and lead. In 1979, the wire reclamation facility had increased operations from one to three incinerators; the new incinerators increased their processing capacity from 45 to 82 tons of scrap per month. Though the incinerators were equipped with after burners, officials of the Environmental Protection Agency doubted that they were operating properly, if at all. The manager of the facility admitted that there was a smoke problem from the incineration of 350 tons of scrap power plant cable. He described the cable as being a 6-in diam eter copper wire core, wrapped in oil-saturated paper, and covered by a lead sleeve. Subsequent to a preliminary in vestigation, the wire reclamation facility was closed by temporary injunction in April, 1980. METHODS The state Environmental Protection Agency requested the assistance of a health effects specialist from the U.S. Environmental Protection Agency {U .S. EP A ), a medical toxicologist, and a veterinary toxicologist to investigate sieged health effects from pollutants emitted by the wire reclamation incinerator. Members of this team visited the site, interviewed the citizens and manager of the inciner ator, collected samples for air pollutant residues, and examined the affected people and animals. We selected the sampling sites based on the predicted behavior of the incinerator's plume, which was estimated using an atmospheric dispersion model and wind rose.13,14 The dispersion model predicted the X max, i.c., the dis tance 10 the point where the plume touches the ground with maximum concentration. The wind rose predicted the sector within the X max area which would be most heavily impacted by the plume. The most distal A" max and most h e jvily impacted sector jr c shown in Figure 1. The sampling scheme consisted of several soil samples, scrapings from two of the thiee slacks, and scrapings from (lie inside of all three furnaces. Water samples were obtained from private wells in the area. All samples were collected in June and July of 1980. The soil sample sites are shown in Figure I. Site No. 1 was located 50 m cast of the stacks. This sample consisted of the top 5 cm of soil. Site No. 2 was located 10 m south of the facility on a spot where oil had been spilled. This sample consisted of the top 3 cm ul soil. Site No. 3 wjs located 215 m east of the facility in the yard ol one ol the affected families. A core soil sample to a depth of 20 cm was collected for inorganics; a surface sample to a depth of 4 cm was collected for organics. Site No. 4 was located 1 km northeast of the incinerator in the pasture where the affected horses had grazed; both a core soil ! sample 10 a depth of 20 cm and a surface soil sample to a depth of 3 cm were collected. Site No. 5 was located 6.U km northeast of a facility in a relatively undisturbed ' wooded area. A surface soil sample to a depth of 3 cm and a core soil sample lo a depth of 20 cm were collected from this site lo serve as controls. F ly and furnace ash samples were collected from the top of the slacks and from the incinerator furnaces, respec tively. A fire department snorkel was used to obtain sam ples from the top of the stacks. The material scraped Irom the stack of incinerator No. 1 was a reddish-brown scale. In stack No. 2, a pale green powder was removed from the base of the spark arrester. Access to stack No. 3 was blocked by a utility pole and a mobile home. Samples col lected inside the incinerators were from the knockdown chamber, the ledge at the base of the stack, and the wall of the primary chamber, in incinerators No. 1, 2, and 3, respectively. All samples were placed in new glass jars and refriger ated. Aluminum foil was placed between the sample and lid of the jar. Samples for inorganics; polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), pes ticides, and phthalates; and nonvolatile organics were analyzed by the U.S. EPA Central Regional Lab according to their standard operating procedures: C R L method No. 571-598, No. 198-207-, and No. 625, respectively.15' 17 Veterinary samples for PCBs and PBBs were analyzed by gas liquid chromatography at the Regional Veterinary Diagnostic Laboratory inC entralia, Illinois. Analyses for TCD D s and T C D F s were performed by Dr. M. Gross at the Midwest Center for Mass Spectrometry at the University of Nebraska using a gas chromaiography/high resolution mass spectrometry procedure, as described in a previous w o rk .7 Citizens who complained of adverse health effects were offered medical examinations in the Occupational Medi cine Clinic at a nearby county hospital. The examinations included a medical history, review o f medical records,' phy sical examination, complete blood count (C B C ), scrurn chemistry screen, liver profile, urinalysis, pulmonary j (unction tests, blond lead, free erythrocyte protoporphy rin (F E P ), and scrum PCB level. One patient (N .C .) had an extensive neurologic work-up before being examined at the Occupational Medicine C linic, the results of which arc also presented. Si-pl i-n itH -r/lk lo b fi 1981 | V o l . 3o (N o . 5 )J 22y X 11.IK 4 N 1 ..5' 0 1 KILO M ETER Fig . 1. Map of area in clu d in g m usi h eavily im pacted sector (d u sh cd Utit s) and soil sam ple sites 1-4, I he veterinary toxicologist examined and obtained a blood lead level on a dog kept in a home loealed 225 m east of the incinerator. Bone lead content was measured in two rabbits taken in the field between ihe home and the incinerator. A lal sample lor PCBs and PBGs analyses was obtained from a chicken raised nejrby. Calves, chick ens, and horses were examined at a small farm located 0.5 km from the incineraior. Frozen liver from two *> J .Ilk Talile 1. Levels of Selected [mirjnL\ in Soil, St<u k. and Turnacc Simples $jr:iple Inmg.mit 1'.ii.nm 'lcisjpptn) Coppei Lead Silvei Chloride Suif iuntplf' 1 -2 3* a* S' Stth /,' Mintpit'' I 1 I'mii.it t 1 J S3 Mi,000 IS 11 19 110 1.18,000 68 37 50 39,000 138,000 37,000 179,000 5 3,000 1 .' .imo 2,600 31,000 1 1.000 6,300 NU K 3 ) f M ND (< .3) NU {< .3} NO (< .3) 25 32 118 9-1 45 46 N A f 44 NA 5S 85,500 h 18S 55 131 *Coic sjfiiplcs. *.\`oi detected j i the detection limit indicated in parentheses. tNot analyzed. calves previously butchered were collected and analyzed fur PCBs, PBBs, jrsenic, lead, copper, and molybdenum. Fresh eggs were tollcctcd and analyzed for PCBs and PBBs. A live chicken was sacrificed for pathologic examination. The liver was analyzed for levels of lead, PCBs, and PBBs; fixed lung tissue was analyzed for metals using energy dis persive X-ry analysis. The veterinary toxicologist examined the horses, feed, and pasture at the horse boarding stable located 1.3 km northeast of the incinerator. Blood, fecal, skin, and hair samples were collected. Blood tests included a complete blood count, serum chemistry screen, liver profile, and blood lead. A p.ost-mortem examination was performed on an 18-yr-nld mare at the slate university's Laboratory of Diagnosi it Veterinary Medicine. Fat and liver samples were Irozen in methylene chloride-rinsed aluminum foil and sent to Dr. Gross for TC D D and TC D F analyses. RESULTS' Pollutant residues. The levels of copper, lead, silver, and chloride in the soil, stack, and furnace samples arc presented in Tallio 1. The levels of copper, lead, and silver in the furn.iccvand slacks reflect their use as metal recovery inciner ators. The high level of chloride from furnace No. 1 sug gests ili.n material incinerated there had contained an appreciable amount of chlorine. Soil sample No. 2, located 10 m south ol the incinerator, contained the highest soil levels of coppei, lead, and silver. The on-site soil samplesNos. 1 and 2 contained higher levels of copper and lead than did the ofi-site and control samples. The levels of organic Compounds m the suit, furnace, and stack samples ate presented in Table 2. Several poly cyclic aromatic hydroc.nbons, usually associated with com bustion, arc present in all three furnace samples, with the highest levels and the greatest variety from furnace No. 1. Many of these compounds (phenjnthrcnc, anthracene, fluoranthene, and pyrene) were also found in soil sample No. 1, collected 50 m cast of the facility. Soil sample No. 2, collected 10 m south of the facility from an area where oil had been spilled, contained 6.9 ppm ul PCBs. Lo w lev els of several phihalalcs, commonly used as plasticizers, were found in soil sample No. 3. Soil sample No. 4, col lected from the horse pasture, contained 0.06 ppm of DDT. Except for elevated iron and total solids, the water sam ples had no abnormal values beyond the maximum contam inant level for public water supplies. Total TCD D and total T C D F levels in soil sample No. 1, soil sample No. 4, furnace No. 2, slack No. 2, horse fat, and horse liver arc presented in Table, 3. The highest levels of TCDDs and TC D Fs were found in the stack sample. Lower levels were loumi in the furnace and in soil sample No. I. TCD Ds and T C D Fs were not delected in soil samplc No. 4 r iL U k s were lound in both horse fat and liver. TCDDs were tound in the horse fat, but not in the horse liver. No known oioxin-contammated pesticides had been used in the area. Medical examinations. Thirteen people residing within 1.3 km of the incinerator complained to state Environ mental Protection Agency officials of adverse health effects. Five people agreed to be examined in April and May of 1980. N .C., a 27-yr-old male, and his wife (C .C .) Had resided approximately 220 m east of the incinerator since 1978. The patient complained of eye and throat irritation, dizziness, and nausea when he was exposed to smoke emit ted by the incinerator. In May, 1979, he had an episode of transient neurologic dysfunction characterized by mild weakness of the right upper extrem ity and face along with blurred vision. In December, 1979, he had the onset of oscillopsia and was noted to have bilateral nystagmus. On physical examination the patient was founcl to have acne vulgaris, upbeating nystagmus in all directions of gaze, mild diminishment of alternate movement rate in the right upper extrem ity, anti a right Babtnsky sign. The following laboratory tests were within normal limits: CBC, scrum chemistry group screen, scrum triglycerides, scrum protein electrophoresis, sed rate, syphilis serology, L .E . clot lest, urinalysis, blood lead, F E P , scrum PCB, and head C T scan. Lumbar puncture showed normal total protein and IgG with a normal cell count. Brainstem auditory evoked res ponses were normal bilaterally, but pattern shift visual evoked responses were abnormal. C .C ., a 28-yr-iild female, complained u f irritation of the eyes and lhro.ii, dizziness, and nausea when exposed to smoke from the incinerator. She complained of a gradual onset of frontal headache and transient visual disturbances since February, 1979. These symptoms persisted after the birth of a healthy daughter in May, 1979. On physical examination, the patient was found to have a maculopapular rash localized in the right scapular area and a 111/VI sys tolic murmur heard at the apex and left parasternal border. Si-pli-mUfi/Oi M in i 19SI I V o i. .1fi (N o. 5] | 231 Laboratory studies, including a CBC, urinalysis, liver pro file, triglycerides, urinalysis, blood lead, f-LP, scrum PCB, and pulmonary function tests were within nurnial limits. S.D ., a 52-yr-old female, had owned hurse boarding stables and a riding school approximately 1.3 km north a X ? east of the incinerator smcc 1966. During the past J yr the patient complained of excessive tearing, rhinitis, episodic throat and chest lightness, occipital headache, and tran sient left-sided paresthesias. She also complained of gener alized weakness, loss of appetite, and joint stiffness. On '-T^W. m - Table 2.--Levels of Organic Compounds in Soil, Stack, and Furnance Samples Organic Parameters *1 Pesticides [ppm (detection limit < 1 ppm)] ! PQBs [ppm (detection limit < .5 ppm)] PCBs |ppm (detection limit ~ -5 ppm)] Chemicals detected from organic scans (ppm): Hexachlorobencenc Phenanlhrene <5 anthracene Methyl phenanlhrene & methyl anthracene Fluoranthene Pyrene Napthalene Methyl naphthalene 2-phenyl naphthalene Hcxachloroslyrenc 9H-fluoren-9-one 9, 10-anthracenedione 7-(1, 1-dimethyl) 2, 3 dihydro3, 3-dimethyl-l H-inden1-one 2, 6-dimethyl-2, 5-hcptadicne -4-one 3, 5,"5-trimethyl-2-cyclohexcn,, -1-one 3 hexen-2-one 2, 5 hexanedione Dodecanoic acid Hcxadecanoic acid Octadccanoic acid Phenol 1-Hcxacosanol 1-Hexacosene 3-Hex enal Methylchiorocyclo-hexane (2 isomers) N-nilrosodiphenyl-amine Di-n-butyl phthalatc Bis (2-eihylhexyl) phthalatc Bulylbcncyl phthalatc Diethyl phihalale Unidentified silicone compounds -t - - -- 1.4 0.3 0.3 - 0.1 - - - -- -- -- 1.5 0.9 1.2 3.6 5.8 -- - - Other hydrocarbons Other unknown compounds --- Soil er3' 4 ` * Samples 5* Stack 1 2 6.9/ -- - 0.06 S - - ---- - ---- -- 0.3 ----- ---- - ----- -- 0.1 0.1 -- - - ---- ---- ---- ------ --- - --- ---- ----- --- -- 110 -- -64 -- -- - 0.1 - -- 0.4 - 1.8 - - #- - -- -- --- -- 30 1.5 (6 empds) 400 370 - - (3 empds) -- 4.3 -- 0.1 ------ --- -- _ .. -- _-- - - -- - - 0.2 -- - - 9.6 (5 empds) - -- -- -- 6 - - - 0.1 - 0.2 - - - - -- -- -- -- - - - - -- -- - .1.3 - Turnau1 =1 ~2 J -- 23.8 481.5 0.4 39.3 37.8 - 1.4 4.1 6.3 .14 9.1 - - 3.5 43 130 - -- 61 - -- -- -- - -- - - - - 3.7 0.2 - - - - 0.7 1.3 1 3.8 - - - 1.5 0.6 - -- 61 (2 cm pds) Surface samples. tPesticides analyzed for were: chlordane, endrin, pp'-DDT, toxaphcnc, hcpuchlor, lindane, dicldrin, and m clhoxychlot. t Compound was not detected. gThe pesticide detected was DDT. f Arochfor 1254. Level delected was not sufficiently high to quantitate. 1 ' VT Archives of Environmental Health physic.il rv.imin.ition the p.nieni was found in have rosaco.1. Ljlio ra io ry studies, including CUC, uiin.ilysis, scrum chemistry screen, hlood lead, and FE P were within normal limits. L .G ., a 24-yr-old male, had resided with his wile (E .G .) approximately 225 m east of the incinerator since 1976. He complained of eye irritation when exposed to smoke from the incinerator, but had no other sympioms. On physical examination he was found to have an erythema tous macular rash over his upper chest and neck. The patient had an elevated cholesterol level of 256 mg/100 ml and elevated triglyceride level of 31 9 mg/100 ml. Other laboratory tests, including serum chemistry screen, blood lead, F E P , scrum PCB, and urinalysis were within normal limits. F .G ., a 24-yr-old female, complained of frequent fron tal headache, blurry vision, nervousness, and an intermit tent sore throat. Her past medical history was significant in that she had viral 8 hepatitis with four recurrences of jaundice since June, 1979. On physical examination she was found to have a macular rash over her chest and back. Laboratory tests, including a CBC, liver profile, urinalysis, blood lead, FE P , and serum PCB were within normal limits. Veterinary examinations. Lead levels in all animal sam ples were within normal limits. No PCBs or PBBs were detected in the fat or liver of the various animal species at a 0.1 ppm limit of detection. The dog was found to be clinically normal. While calves at the small farm had not grown as well as previously owned calves, their rations contained a fairly poor quality hay and shelled, but uncrackcd corn. The two horses received adequate rations and were kept in a barn at night and suffered no note worthy illness. The chickens were normal in outward appearance. The necropsicd chicken had no significant gross lesions. On histopathology, there were accumula tions of dark, irregularly shaped masses, prim arily within macrophages, around airways; there were also microfocal lymphoid aggregates adjacent to the airways. Energy dispersive X-ray analysis of the chicken's lung revealed elevated levels of aluminum, palladium, titanium, and silver. The copper content of the calves' livers was low at 6 to 16 ppm. We could not determine whether the horses kept at the boarding stable located 1.3 km northeast of the inciner ator had been receiving adequate feed. At the time of the first visit, the pasture appeared overgrazed, the oats were of poor quality, and the hay in feed bunks was in short supply. A t a subsequent visit, however, the feed was plenti ful and of good quality. T he horses most severely affected and all those that died had been allowed to remain in the pasturF located 1 km northeast of the incinerator at all "times. Horses kept indoors were either unaffected or much less atlcc tc d' -------------------------------- SeveraTof the horses present were nolicably under weight. Three had alopecia on their dorsal aspects with exfoliation and hypercmic margins; large hair-containing crusts could be peeled away. CulturcTailed to recover organ isms apart from Aiternaria, a contaminant. One extremely underweight animal had paraphimosis. Three of five ani mals' fecal samples revealed only small strongyles from 200 to 400 cgfis/g. The horse identified as the "broodmare" had small strongyles, as well as Strongylus edentatus and Triodontophorus sp. with an egg count of 1700 eggs/g. Egg counts are difficult to interpret because of the temporal var iability of egg shedding by intestinal parasites. There was no clinical correlation between the animals' conditions and fecal egg counts. Complete blood counts on three animals revealed no abnormalities. Scrum profiles revealed consistent decreases in albumin. Post-mortem examination of a marc that died in June, 1980, revealed a tear in the colon near the cecum with extensive secondary peritonitis. She had appeared in good flesh at the lime of the initial visit, although she had been among the severely affected original group. She had given birth to a blind foal and a stunted foal. Her fecal samples had revealed small strongyles, Strongylus edentatus, and Strongylus vulgaris with an egg count of 2200 eggs/g. On post-mortem, there were pathologic anterior mesenteric artery changes consistent with Strongylus vulgaris larval migration. There was a fibrous band extending from the tip of the cecum to the right body wall compressing the colon. Histopathology revealed foci of macrophage accum ulation in portal areas of the liver. There was mineraliza tion of the renal tubular cells and slight thickening of Bow man's capsules and glomerular tufts. Forty-five parts per trillion (ppt) of total TCD D was detected in the mare's fat; no TC D D was detected in the mare's liver. One hundred sixtyTive ppt of total T C D F was detected in the mare's fat and 57 ppt of total T C D F was detected in the marc's liver. D IS C U S S IO N Our study demonstrates that a wire reclamation inciner ator; can be a source of environmental contamination with TCD D s and TC D Fs. These compounds may have entered the incinerator intact in the fuel or charge. An alternative explanation is that they were formed in the complex chem istry of combustion from precursors found in wire insula tion. Human and animal exposure to airborne TCD Ds and TC D Fs appears to have been very low, as indicated by the Table 3 .-L e v e Ij of Tetrachlorodlbenztvp-Dloxlru (T C D D j) and Tetrachlorodtbenzofurani (TC D Fs) In Soil, Furnace, Stack, Horse Fat, and Horse Liver Samples Sample Total TC D D s (ppt) Total T C D F s (ppt) Soil No. 1 Soil No. 4 * Furnace No. 2 Stack No. 2 Horse fat Horse liver 21 ND (< 3 ppt) 1 58 410 45 ND (< 6 ppt)t 230 ND (< 3 ppt)t 730 11,600 165 57 'Surface sample, f Not delected at a detection limit o f 3 ppt. | Not detected at a detection limit of 6 ppt. September/October 1981 [Vol. 36 (No. 5)] 233 U.ttc (.iintuniraiiuns <>( these residues in the .L*b, suil, ,iiid burse (issue samples. The most toxic of the 22 1'CDD and 38 K .ilK isomers are 2, 3, 7, 8 TCD D and 2, 3, 7, 8 T C D F . II' U>so \ 1 ihcsc compounds arc in the order of microy.rams per kilo gram in many animal species. 2, 3, 7, 8 T ( DO is a m ulti system'toxin, teratogen, fciotoxin, and carcinogen.18 The dose-response relationships of these compounds in humans and horses arc largely unknown. As we were only able to measure total TCDDs and TC D Fs, we do not know whether the highly toxic 2, 3, 7, 8 isomers were present in our samplcs. We concluded that many of the acute human health effects in the present case were caused by exposure to air pollutants commonly found in the smoke emitted by J improperly controlled wire reclamation incinerators. These pollutants include carbon monoxide, halides, nitrogen oxides, sulfur oxides, and other pyrolysis products.1*3 There was no evidence of lead, copper, or silver poisoning in the humans ur animals. We could not establish a defin ite association between the human health effects and the exposure to trace amounts of TCD Ds and TC D Fs. One person had longstanding acne vulgaris, but neither he nor any of the others had a condition resembling chloracne. While visual disturbances, nystagmus, and polyneuropathy have been previously described in persons exposed to 2, 3, 7, 8 T C D D ,18 the present exposure appears to have been much lower than in the previous eases. The presence of trace amounts of TCDDs and T C D Fs in the horse tissue is evidence of exposure rather than into xi cation. The absence of TCDDs and TC D Fs in the pasture soil sample suggests that inhalation may have been an impor tant route of exposure. There arc no data on the kinetics, metabolism, and critical concentrations of TCD D s and T C D F s in horses. The symptoms in the affected horses were remarkably similar to those described in a previous TC D D poisoning episode.19*30 In the previous episode, however, the horses had been exposed to soil contaminated with part per million levels of TCD D s; no tissue levels of TC D D were available from those horses for comparison. TCD D s and TC D Fs have previously been detected in the fly ash of municipal and industrial incinerators.4-* 18 Oper ators of wire reclamation facilities should be aware that the potential exists for the emission of these compounds from wire reclamation incinerators. Data collected to date on the toxic, carcinogenic, teratogenic, and fetotoxte potential of the 2, 3, 7, 8 isomers warrant concern over trace environ mental contamination with TCDDs and T C D Fs. The authors wish lo acknowledge the support of the U.S. Envir onmental Protection Agency Central Regional Laboratory, the Illin ois Environmental Protection Agency Laboratory, and Cook County 1luspilaf. Submitted tor publication July 2, 198 1; accepted lor publica tion August 22, 1981. Requests Tor reprints should be sent to: bjniel IIry h o 'i/u k , M.D., Section of Occupational Medicine, 720 S. Wolcott, Chicago, IL 60612. RLTCR IN CLS 1. D an ie lso n , | .A . 1973, A ir P o llu tio n Eng in eering M a iiif.il, P u b li cation No. A P -40. W ashington, U .C .: U .S . environm ental I'm lection Agency. 2. Kimbrough, R.D, 1972. To-vicity of chlorinated hytliui.irhnns and related compounds. Arch Environ Health 25: 125-3). 3. Petkus, E .|.; Thorp, W.1.; Kimura, G .; and l.in n j, L.W. 1979, Chloride and Heavy Meta! Emission* from Wire Burning Inciner ators Paper presented at the 72nd Annual Meeting of the Air Pollution Control Association held June 2*1-29, 1979, Cincin nati, OH. 1. Olie, L .; Vermeulcn, P .L.; and Huizingcr, O. 1977. Chlorodibenzo-p-dioxins and chlorodibcnzofurans arc trace components of fly ash and flue gas of some municipal incinerators in the Nether lands. 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