Document zzbJYmnbw1vke45aV08KrZ020

feature PCB's--prevalent and persistent Intensified research is needed to minimize their dangers Carl 0. Oustafaon, Federal Water Quality Administration, Athens, Ca J)uring (he past three year*, a special clus of compound!, called polychlorinated biphenyls (res'*), has claimed the attention of ecologists and pesticide analysts in (his country These compounds were not discovered in the environment until 1966 in Swe den and 1967 in the U S . despite the fact that they have been available com mercially for 40 years Interest m pea's has arisen because they arc frequently found in fish, bird, water, sediment, and other environmental samples when such samples are examined for chlori nated pesticide residues That a wide variety of samples containing peas has been collected from England. Scandi navia, The Netherlands, Antarctica, Central America, and many different parts of the U S makes them truly ubiquitous pollutants. Polychlorobiphcnyls arc made by substituting chlorine atoms for one or more of the hydrogen atoms at the The Monsanto Co stated recently In a biter io Congressman William F, Ryan of New York that as of August 30, It would no longer sell Pcn'r to customers for use In general plasticizer opei mions where disposal of the endproductt cannot he controlled, After some lag period--the time It takes to eventually dispose of the products made from pcb's and currently In processor's Inventories--the quantity of pcb'j getting into the environment may be substantially reduced If Monsanto's former customers look for PCI* substitutes, rather than purchasing Pea's from manufacturers in Japan and Europe, the protected decrease could become a reality, Carl C Gustafson 114 FnvlrDnnei,'el Science & TtinolO(v numbered positions of the biphenyl structure In the process of replacing hydrogen atoms with chlorine atoms, a large number of substitution combinations arise For example, three monochlorobiphenyl isomers are posaibte, 12 dichiorobiphenyl isomers, 2! trichlorobiphenyl isomers, and so on. Theoreti cally, 210 compounds can be prepared by this substitution process; a typical example would be 2,4,6.2'4-peniachiorobiphenyl Whenever aromatic hydrocarbons such ts biphenyls are chlorinated, the product is a mixture of compounds, in cluding isomers It is quite difficult to synthesize single, specific chlorobiphenyl compounds in the laborttory unless involved procedures are em ployed. Consequently few of the indi vidual compounds have been prepared in the pure form for study. In the commercttl process for pea manufacture, biphenyl is chlorinated with anhydrous chlorine in tall cy lindrical towers with either iron filings or ferric chloride as the catalyst. The by-product is hydrogen chloride, the product is a mixture of several peas The degree of chlorination is deter mined by measuring (he specific gravity of the mixture or, when the product tl more viscous, (he ball-and-rtng softcning-point test is used The whole pro cess takes from 12 to 36 hours In the US, the sole manufacturer of rcR`s is the Monsanto Co , which markets them under the trade name Aroclor. pcb's are also manufactured in Europe and Japan, under trade names such u Phenochtor and Clophen The various Arociors ire dif ferentiated by a four-digit number, with the last two digits indicating the percentage of chlorine in the mixture Properties The three most important physical properties of the pc*T are low vapor pressures (they have high boiling points), low water solubility, and high dielectric constants They are mis cible with most orgtmc solvents and compatible with many types of poly mers Although some individual polychlorobiphenyl compounds are crys talline, the Aroclor mixtures are either liquids or resins The chemical properties that make rca's desirable industrial materials are their excellent thermal stability, their strong resistance to both acidic and basic hydrolysis, and their general in ertness They are quite resistant to oxidation. Monsanto reports, in a tech nical bulletin on pea's, that (hey can be healed to 140 C. under 260 p s i of oxygen pressure "without showing any evidence of oxidation as judged by de velopment of acidity or formation of sludge" The physiological properties of the pci's mike them potentially significant contaminants of the environment. For any pollutant, two factors are involved acute toxicity, which is immediately evident because of a high death rate or other maiming effect, and chronic lox icity, which Is (he result of s slow ac cumulation of (he poison in the body and is a sublethal effect. Whenever acute toxicity is high, a pollutant will be readily recognized and appropriate remedial actions Will be introduced If. on (he other hand, acute toxicity is low, HONS 212860 ihc phyuolofieil effects will go un noticed until tbe chronic effect* melee ihemseivci evideoi When this htppen*. the problem mey hive edvenced be yond immedlete or eey correction Aeute tuhltr All siudie* of pea's in enimel* indicsie ihii ecute toxicity i not e *i(niflcem factor Their ecute toxiclUes ere on the order of tho*e of other chlori nated aromatic compound* Monsanto ha* sponsored two investigation* of i he aeuie loxiciiies of Aroclor mix tures In the first, at the Kettering Laboratory at the University of Cin cinnati. Dr J F Treon and his co worker* investigated the toxicity of Aroclor vapors for guinea pip, mice, rabbits, and rats Ail animals survived a 24-day exposure to 0 83 ppm of Aroclor 1242 for 7 hours per dey on 17 of those days Even after more pro longed tests, there were no severe effeels from Aroclor 1242 In the second investigation, still in process, three groups of beagles are fed Aroclor 1242. 1254, and 1260. respectively, at a rale oflOOppm in their diets After three months no significant abnormalities htvc been noted Similar studies on Hsh have been per formed m several laboratories Dr Richard Schoctlger of the Sport Fish eries and Wildlife rh Pesticide Re search I ithoraiory in Columbia Mo . reports ihnl 96 hour-TLH roxicilici of the Arodors to trout range from I 17 to no p pm Compared to dot, whose 96 hour-Tt -,,, toxicity is 0 002 to 0 009 ppm for trout, the Pen's have a rela tively low acute toxicity With the more aensittve hluegill, the 96 hour-TLM for Aroclor 1248 is 0 278 ppm. while that of dot is 0 008 ppm Aroclor toxtcutes appear to he inversely propor. tional to the chlorine content of the mixture Shellftsh. oysters, and shrimp are more sensitive to PCI'S Dr Tom Duke, at the Bureau of Commercial Fisheries Fusticide Field Station, re ports 100% mortality of juvenile pink shrimp exposed to 0 10 p p m of Aro clor 1254 in weler for 48 hour* This conccntrsuon cf Aroclor 1254 wilt cause a 100% decrease in shell growth of oystcre after 96 hour* To achieve lhe same effects with dot in these ex periments. only 0 0006 ppm and 0 01 ppm. respectively, were required There is very little evidence that pea's are lnxic 10 insecu Studies to dale show that ihey are less toxic ihan dieldnn or dot As with Rsh. their tox icity appears to be toveraely propor tional to the chlorine content of the mixture Baaed on the above data, it is un derstandable why the polychlorobipbenyls, commercially available for 40 years, have only recently attracted attention a* toxic environmental con taminants Chrasste Mikity The cbronic toxicities of pea's pre sent a more disturbing situation, severat chronic effects have been observed. It was discovered, quite by accident, that pci's have a toxic effect on chickena Professor E L McCunc and his co workers at the University of Missouri found l heir chickens dying afltr Ihey were placed in a feeding bouse, parts of which had been freshly painted with in epoxy paint Careful investigation revealed that the toxic factor was Aro clor 1242, a bsnder in the paint When Aroclor 1242 was fed to (he chicks it produced tbe same characteristic effects as chick edema factor McCune re ported "Gross pathology included hydropencardium, hydropentomum, en larged heart, liver, and kidneys, and hemorrhage of internal organs Mi croscopically the kidneys showed marked tubular dilation and numerous casts ' Another chronic effect of pea's is reined iu wildfowl The sccumulalion of high concentrations of chlorinated hydrocarbons in birds resulted in dis ruption of normal breeding behavior and in the formation o( thin-shelled eggs A dramatic example of this effect his been observed in the case of the brown peiicen On the Anacapa Island! off the California coast, no young were hatched last year from 300 pairs of nesting birds The shells of most eggs laid were so thin that a dent occurred when the egg was picked up Thera are lwo possible ceuses for the laying of ihin-sbetied eggs by wild fowl On* is a low calcium reserve in the bird, the other is the inability of lhe bird io deliver the needed calcium o its oviduct, where the eggshell ii forming The cetcjum level in the avian biosystcm and the calcium reserve in the secondary bone structure or medul lary bone, found only in female birds when they are breeding, sre controlled by the hormone estrogen A high es trogen level is associsted with the for mation of ihn calcium reserve Chlo rinated hydrocarbons, such as dot, Vetunw 4. Number ID, October 1170 Sli HONS 212861 chlordane, dieldrm, and pea's, activate tnzyme* in the liver which transform estrogen into a more water-soluble compound that is readily eliminated from the bird's body This meant that when tslrogen level* are low, calcium rttervet will alto be low. and there fore very little calcium will be avail able for ttrong eggshell production Dieldrin and pCb's are more effective than nor in this type of enzyme-Induc tion activity Aroclor 1262 haa an etiradiol degrading potential four to five timet that of p.p'-Dot or technical grade nDT The ability of the female bird to deliver calcium to her oviduct during the last 20 hour*, when the eggshell is being formed, is related to the func tioning of the enzyme carbonic an il yd rate When birds that have ex hibited the ability to lay normal eggs arc injected with a metabolite of dot (onr i just prior to the formation of the eggshell, they will lay thin-thelled eggt This indicates that dot alto in hibits the activity of carbonic anhydrasc. ihc enzyme that control! the How of calcium from the blood stream of the bird into its oviduct Since dicldnn seems to have no effect on carbonic anhydrase, we may assume that neither do the pea's How ever, these compounds delay breeding time significantly Many ornithologists feel thnt late breeding has a stronger influence on the reduction of bird popultmons than does the laying of thm-shclled eggs If this is true, nca'i arc a more potent threat than dot to our declining bird populations, es pecially for predatory birds that ac cumulate fairly high levels of pea's be cause they eat smaller ammala that al ready have concentrated pci's in (heir own tissues Other investigators have produced evidence to show that pea's are simi lar lo ddt in their activity. Dr Joseph Street at Utah State University has shown that when pea's accumulate in the liver, they induce microaomal en zyme activity by bringing about more rapid metabolism of diugs, inaecticidts, and other foreign compounds He fed rati a diei containing JO ppro of Aroclor 1254 or Aroclor 1260 After 10 days on tins Jici, the test animals were administered hexobarbitol at a dose of 100 ppm to induce sleep In comparison with s control group, the sleeping time for these rats was reduced by 65 to 809 Street slso found (hat Aroclor, when fed at the lit Ettvinnewnlil Science A Ttchadotr same level, will reduce dieldnn stor age in adipose tissue by 90 to 959, increate aniline oxidation by 200 to 3009, and increase epn detoxication by 430 to 4709, In addition, (be pea's cause activation of organothiophosphate compounds, which adversely af fect the ayitem Thu latter effect coun terbalances the detoxification of diel drin Normally, when a subslrate activates an enzyme, tt is converted to a watersoluble form (hat will be eliminated from the4ystem: however, this is not the case with pea's Because they re main in (he system for prolonged pe riods of time, thetr enzyme induction activity ts always presenl In this way the normal concentration of important body chemicals may be lowered to (he point of bringing about malfunctions in the sysiem For esample, Street be lieves (hat (he pea's bring about steroid degradation, which can lead to aliered endocrine relationships The chronic toxicity to man is aa follows Like tbe chlorinated naphthalenes, the chlorinated diphenyls have two distinct ac I ions on the body, namely, a skin effect and a to sic action on the liver The lesion produced in the liver is an acute yellow atrophy This hepaio-tosic actioo of the chlorinated di phenyls appears lo be increased if there it exposure to carbon tetrachloride at the came lime The higher the chlorine content of the diphenyl compound, the more toxic it n liable to be Oxides of chlorinated diphenyls are more MOWS 212862 lone ihati ihe unotidmd miIcriais The skm lesion is known as diloracne, and consists of small pimples and dark pigmentation of the exposed areas, initially Later, comedones and pusiulct develop In perions who hive suffered sysiemic intoxication the usual signs and lymptoms are nausea, vomiting loss of weight, jaundice, edema, snd abdominal pain When- the liver damage has been severe, ihc patient may pass into coma and die Jni N /rinrip "'Danprroui Propftiu\ nf liuhiitrtal Mmrrirtlj." -J'd ftl t'nii 6lnitrar>d-Rr\nhold, Nr* 1'nrl 1968 1 he ubiquity of pen s is related to Ihc wide spcClrum of applications that have been found for them The largest single use of Piss is related to their electrical properties--as coolant-insu lation fluids in transformers For this purpose the Arocksrs arc also sold under such trade names as Chlorcxipl (Allis-Chalntcrs Mff Co 1. Dykanol (Federal Pacific Electric Co !, Incrteen (Wcsnnghousc Electric Co 1. Noflamol (Wagner Electric Co ). Pyranol (General Elcclrie Co ). and Thcrminol (Monsanto Co.) Other uses of pen's include formula tion into hallasts for fluorescent fix tures, impregnation of cotton and as bestos for h raided insulation of elec trical wiring, a plasticizer in wire and cable coatings, capacitors and askarcl- type transformers, and plasticizers of vinyl eh'ortdc polymer films Because of their thermal stability and fire re sistance, the PCX's also find application tn high-presxure hydraulic fluids, spe cialized lubrtcfnts end gisket sealers, hc.it transfer agents, and machine tool cutting oils Miscctlaneoui uses in clude formulation into some epoxy paints, protective coatings for wood, metal, and concrete; adhesives. and in carbonless reproducing paper. One of the primary manufacturers of carbon less reproducing paper also aelia Aredors m an encapsulated form Generally the kinds of applications described above mean that the Pea's will be in many types of products that eventually find their way to the domes tic market When used in manufacture of ballasts for fluorescent fixtures they will be found in kitchens, bathrooms, stores, and offices through nut the coun, try Wherever office forms are used that do not use carbon paper, one msy find pen's formulated into the micro capsules of dye that comprise the re Haptaehtor Lindait# AJdrin Heptachlor Oxlda , DDE p,p* DOT Oai ctiromctOfrim Alioft standard pesttcida mixture, B It typical of Aroclor 1254. and A + B i* tha chromatogram of a 50 ; 50 mixtura of both Tha concentration of Aroclor 1254 la approwmataly 10 tlmaa thoaa of tha paatiddaf In A. hanca it If un doratandapia why PCB'a wara not readily recogntzad In pattlclda chromatograms. Qee chromatograph (Packard 7620) conditions- gat flow 80 mi /mm. nitrogen, tarn peraturei--oven. 210* C.. inlet, 230* C , detector. 21S* C : Nf" electron capture detector; 5' x glatf column packed with BrA SE 30 on Chromoaorb Q B0-90 mefh producing layer of the business form pea's have also been found on the transparent receipts used in credit card charge forms As plasticizers they can be expected to appear in many con sumer plastics Since the chrome toxicities arc so significant, it becomes important to know just how extensively ihe prnT ire distributed m the ecosystem, and just how they find their way into the environment Rainwater in En gland, brown seals off the coast of Scotland, while-tailed eagles >n Swe den. cod m the Baltic Sea, mussels in The Netherlands, adclie penguin eggs in the Antarctica, brown pelican eggs in Panama, Arctic term, shrimp m Florida, river water in Japan, waters in the Great Lakes, human hair, and human adipose tissue--samples of all these have been found to contain ri a s, Vehm 4. Nunbw to, Ociaksr Itto etl HONS 212863 thus making them * class of widely dispersed pollution. RMdlty absorbed The properties of rca's that make them industrially useful are the same properties that cause them to persist in the environment. These in clude thermal stability, resistance to oxidation and hydrolysis, solubility in a wide range of organic solvents, water insolubility, high dielectric constant, and compatibility with many types of macromolecules Their resistance to oxidation and hydrolysis also makes rca's more stable and persnient than ddt Consequently, they could even tually accumulate to higher concen tration than dot. eapeciaily if the ute of ddt is sharply curtailed in the U S The solubility of rca's in nonpolar solvents explains why they are readily baorhed into fatly usaue and into the liver Their resistance to oxidation or other types of chemical degradation explains their persistence in the en vironment and accumulation tn animal fissile The latter effect is enhanced both hy their insolubility in water and solubility in organic solvents Their chemical inertness and resistance to metabolism account for their tow acute toxicity But as they slowly build up in a living system their con centration approaches toxicity levels, at which point .chronic effects make themselves evident It has been established that Ash-eat ing birds will accumulate targe concenttslions of rca's, as in the case of the white-titled eagle, which has been found to have as much as 14,000 p p.m, of rcs's Peregrine falcons, taken off Ihe coast of California, were found to have as much as 2000 ppm in their itpid tissue When ihnmp were exposed to 10 ppb of Aroclor 12S4 for 48 hours, they accumuialed 1300 p.p.b. of rca's, which represents s 130-fold con centration in a very short time. Oysters, exposed to an identical concentration of Aroclor 1254 for 96 hours and then placed in rca-free water for four days, still had a concentration of 33.000 p.p b. of rca's, which constitutes a 3300-fold concentration This means that even though the concentrations of rca's are in the parts-per-biilion range in the environment, their high lipid solubility causes them to collect in fatty tissues of lower animals and marine life Therefore, species at the top of a food chain will also accumulate rca's in their bodies, particularly in their iipid tissue and liver, in much the same III Eiwlremnental Scknee 4 Tedmetagy way is they accumulate DDT and oiher chlorinated pesticides. Because of the low solubility of rca's in water, when a solution or dispersion Of them is discharged into a river or lake, they wilt accumulate on the sedi ment in relatively high concentrations Subsequently, they will redissolve very slowly in the water aa conditions change. Therefore, it will usually take a long time to flush out a contaminated area Accidental eccumnce The reason that rca's have not been found in the ecosystem as extensively as DDT, and are not preaent in environ mental samples at as high a concen tration as dot, is that rca's find their wsy into the environment accidentally ddt is deliberately spread because this s ihe only wsy its insecticidal proper ties can he utilized rca's are not in tended in get into the environment, but (hey do because their unique chemical properly prevent them from being de stroyed hv our usual waste disposal methods Thus, they inadvertently es cape and become widely dispersed In Sweden, where the use of ddt has been banned, and where the main power source it hydroelectric, investi gators And that the concentration of rca's tn the environment is is high as that of ddt. There are several ways by which rca's get into the ecosystem One of these h by incineration Products con taining pel's, such as carbonless re producing paper in business forms, plastics (especially polymer Aim and sheeting that contain rca's as plasti cizers), spent ballasts from fluorescent light Axturet, and objects coated with rca-formulated coatings, all And their way to the city dump or incinerator for burning. The rca's do not burn but are vaporized, They are then carried into the atmosphere, where they collect on particulate matter and are subse quently returned lo the surface of Ihe earth, into the rivers, lakes, and oceans. In this way they become widely dis tributed throughout the global environ ment. Another source ti probably land run-off from industrial wastes snd dumps A third source is the point of manufacture and ihe plants where pea's are processed into other products. They can etcape through (he plant ven tilation and exhaust systems into ihe atmosphere and through its waste treat ment system into sewers or directly into waterways HONS 212*64 I< is interesting to note thst the tncidense ol rce a in environment*! sam ples is highest in industrialized *nd ur banized aresi Birds whoM primary hibnai is the S*n Fnnciico B*y area have larger concentration of pen's per unit of body weight than those locitcd in Bait, Calif, which is com pletely rural Aquatic life tn the Archi pelago of Stockholm, the moat induiirializcd area of Sweden were found 10 have a higher concentration of rm'1 ban lixh samples taken froni the wcxl,rn coasi of Sweden, a less developed ire.i Sediment samples lukt-n from -onihern purl ions of I .ike Michigan i tve a higher concentration of Pea's h.m ihoce from other parts of the lake Monsanto slates that until a recent .tiangc in marketing policy I see meet, page Hill, sales of Aroclors were Ul- rcasing al ihe r,.tc of SW per year while this increase docs not seem sigidicani n may he important if the inreased consumption was in consumer products and ihus would hnd rheir way into our normal solid waste disposal -vstems Such an occurrence would mean a definite increase of pi it residues in ihe environment, and therefore a marked increase in their chronic toxluty effects DltKtlM rrn's were not discovered m environmenul samples until very recently for several reasons First, as indicated hove, they have not been deliberately distributed ahotn the ecosystem Sec ondly, because of their relatively low acute toatcities, their presence was not immediately evident Finally, they are difficult to detect enelytically The pea's were first detected ts in terfering peaks in the gas chromato graphic analysis foci of environmental samples being analyzed for chlorinated pesticide residues When pet's are pres ent in i sample they give a pattern of several cc peaks, whose retention times re similar to those of ditTdnn, DOT, nut!, aldrin, and hcplachlor oxide Be cause the peaks were not large or sharp, investigators tended to ignore them until S Jensen, In Sweden, end R Risebrough, at the University of California al Berkeley, identified them is corresponding to common constitu ents of environmental samples being analyzed for persistent pesticides. The problem of Ihe interferences of mi t With ihe analysis of other chlori nated pesticides has been largely over come h> prior treatment of the sam ple Several investigators have -used column chromatography to separate pea's from chlorinated pesticides At a recent meeting, sponsored by the pwqa's National Water Quality Lab oratory, Duluth. Minn , a general pro cedure was recommended for separa tion of pea's from pesticides In this procedure for biotamples, the sample is extracted with hexane as in regular pesticide analysis It ts then partitioned with acetonitrile to remove fats. Ihe eletmed-up extract is passed through a Fluorisil column and then through a silicic acid column Finally, the sample is analyzed by gas chromatography, with a chloride-specific detector fn this way the pesticides are retained on the silicic acid column for later elution and idcnlifi canon Research needs To assets fully Ihe significance of Mi as environmental pollutants ad ditional research is needed No one really knows Ihe extent of Ihe chrome effects of these chlorinated hydrocar bons Some problems that need to be considered are Although Pea's arc known 10 ac cumulate in human organs are do not know at what concentration they will begin to exhibit toxic effects Will iheie chronic effect* be similar to those shown in animals--microsomal en zyme icityhy. calcium metabolism in hibition. and *o on7 What are other possible chrome effects? Which of Ihe many pea com pounds in the commercially available mixtures are responsible for their tox icity' Can commercial pc* mixtures be modified to eliminate the toxic com ponents? Pure samples are required to answer these questions At the present time work is continuing at the fwox's Southeast Water Laboratory to sep arate each of the Arodor mixtures into its many components, and to identify each component We need to know all the uses for (he Pea's What u the annual produc tion of pc* s? Our knowledge of these facts is limited and needs to be ex panded These fact* should be known if we arc to accurately determine how they get into the environment, and lake steps to prevent further environmental contamination by them In view of the complexity of the isolation and accurate quantitative analysis of pcd'i m chlorinated resi dues, a straightforward, unambiguous measurement of (hem needs to be de veloped ' What is the fate of pea's in nat ural waters? More needs to be known of their partition coefficient! between bottom sediments and water This it vital if we arc to estimate how long it will lake for a river bed to clean itself of contaminalmn It will also be useful when assessing the effects of rca* on marine life that feed on the bottoms of lakes, rivers, and estuaries We should also learn more about rca solubility in water of various ionic strengths * Are present wtite treatment sys tems adequate to handle pea's' Do spe cial measures need to be taken when pea's art pari of the waste effluent be ing treated'' By trying to gel some of these an swers now, we may find that we arc in a position to control the escape of hiss into the environment before ad ditional damage is done So frequently, action is taken only after it is evident that massive damage has resulted from a particular pollutant In the case of ihe hhswd may have an opportunity to resolve the situation before that happens Additional Reading Hubbard, H L, "Chlorinated Biphanyl and Related Compounds " Eneyetopadia of Chamtcal Technology, 2nd ad , S, Interscience Publ. New York, N V , 1964. pp 289-296 Reynolds, L M . Bull Environ Content. Toxicol 4.128 (19691 Risebrough R N . et el. Nature 220 (1968) Cert G. Gustafson, thairman ol the Department o/ Chemistry nf King's College, Bnarchff hlatlor A Y re ceived a Ph D in Orpitmc chemistry from the University of t)% taware tn I9S7 During the 1969-70 arudemic year, he was on irave at ihr fwqa Southeast Water Laboratory in Athens, On where he situltetl trace organic analysts in waste effluents As a mem ber ol rite National Watt i C ottiamlmints Chttraeiertzaiton Rest an U Pro gram he work ft! a t/h HrHi tmtl pulp and paper mill effluents Volume 4. Number 10. October tit# Ilf HONS 2120*5