Document 6ROax0nk0wKg9dbpDqe2nRxm9

n&xvue /vgu/en/ 1/3 y ( /17iJ Pesticide residue analys s in the presence of Folyclilorobiphc lyls (PCB's) By L. M. Reynolds* Content: I. Introduction..................................... . . . '...............................27 II.Presence of FClt's fn lhe environment ......... 31 III. PCD interference with pesticide rcsich e analysis....................................32 IV. Uses and pri|HTtc% of PCD's . . ................................................. 34 V. PossiVde mode* of entry uf PCD's ink tho ecosystem.........................34 VI. Toalwty of PCD's........................................................................................... 30 VII. Analysts of prUicido tesidues In the pr sence of PCD's.........................37 VIII. CunhrniAli'm of pr.tiuile identity . 38 IX. Identification of PCD's in samples ....................................................... 40 X. Estimation of PCD's........................................................................................... 44 XI. Separation id PCD's from orgnno| hosphorus compounds by the Florisit tcchnitjue............................... 45 XII. Residues of organocltlotine pesticides tod PCB's in Canadian wildlife 45 Summary................................................... 52 Xhuini........................................................ ..................................... , . 53 Zusammtnfassung...................................................................................... ' . . 54 References................................... 54 I. Introduction Although there has been so much discussion on the pros and cons o pesticide use, it would be unthinkable to start this review without a few comments on the controversy. The recent banning of DDT by some countries and the widespread and increasing animosity to* wards the use of the organochlorinc pesticides in general are due to t number of factors including: a) Tho large annual additions of the pesticides to the environ* ment coupled with their apparent persistence. b) Their known acute tovicities. c) Their widespread distribution in biological materials and their reported buildup in the food chains. * Ontario Research Foundation, Sheridan Park, Ontario. Canada. 27 MOMS 08415 7 U M. Axwou* d) Their more recent implication in the derangement of calcium metabolism (Pkaxau. 1907, Sr (kis 1967, Welch ct al 1969) possibly causing the decrease in eggshell thickness and the population decline of certain raptorial species of birds (IUtcliffe 1907, Hickey and Avdewon 1G6S, Stjcxel 1969). e) Their adverse effects on fish rep oduction (Bonoxac et al 1964) and high residue levels found i \ Coho salmon in Lake Michi gan in 1909. f) Certain Tears'* involving chroni. toxicides and sublcthal doses with possible deleterious effects on man and wildlife and the ultimate survival of man. The alrovc factors are very compclli ig and certainly warrant man's concern about the threat to lus enviremnont and his very existence. Nevertheless, one cannot deny that the e pesticides have been impor tant in ensuring the supply of man's r; oidly increasing food require ment and in the protection of his herlth, as well as the saving of millions of lives. Surely, this is a case \v icrc the benefit-risks equation IS well as the alternatives to the orgmochJorine pesticides should M carefully studied and evaluated to a mid the possibility of getting nto a worse predicament It was quite ironic when recently a large city publicised that, lectuse of an impending ban on DDT, the garbage collector would pick up separately all home garden sprays and other mi^erirds which *ontnin:d cvui traces of DDT. The material that had been used nore than generously and cherished for t huost 30 years had suddenly lecome monstrous even in trace quantities. Wasn't thrre much greater danger posed to the collectors, children, and animals by such collec tion than if the home supplies had been allowed to run out gradually vt1th no chance of replenishment? In fact, the announced bans on DDT so far are generally not tetai, and hence serve the same purpose as merely tightening the control on the uses of such pesticides. In other words, when it is necessary, and until suitable and satisfactory replacements are avail able, limited and judicious use will be made of these pesticides. With regard to the use of substitutes, caution is essential to avoid Premature use of any compounds. It is now known that potentiation or antagonism) of toxicity is possible with certain combinations of pesticides and with combinations of pesticide and drugs or environ mental chemicals (Dwois 1963). A compound might be fairly safe by itself yet harmful in (he presence of others. It is a fact that even if suitable substitutes were found and the Ufo of the organochlorinc pesticides was banned completely, a need would still exist for at least a number of years to have reliable analyti cal methods for the determination of their residues. Tire present re view discusses the status of organochlorine pesticide residue analysis HONS 064156 _____...______ _________ .*jhnjb tI derangement of calcium m, Wblch et oL 1969) phtU thlckneu and the Oriel ipedes of birds ON 1968, Sncm 1969). too (Burnnac et cl 1904) o salmon Jn Lake Michi- Mm and sublethal doses nee end wildlife and the id oertatnly wan sot man's It end his very eaistence. sriddei have been imporf toereailng food requireas well as the saving of the benefit-risks equation hlorine pesticides should I the posaibllity of getting large-*1ty publicised that, (an, ;e collector would lana outer materials which esiel that had been used nost 30 years had suddenly Wasn't there much greater nd animals by such colleclowed to sun out gradually T so far are generally not a aa merely tightening the to other words, when it is rosy replacements are availmade of these pesticides, caution is essential to avoid ow known that potentiation rith certain combinations of ieldo and drugs or environpound might be fairly sale idtutes were found and the I banned completely, a need fears to have reliable analytirir residues. The present rebe pesticide residue analysis I mrn< miw.h . Polychlorobiphenyls 19 with particular reference to serious inaccuracies caused by tbe pres ence of polychlorobiphenyls (PCD's) in some samples. As would be expected, in order to cope with the numerous new pesticides that have been put into use, pesticide residue methodology has changed drastically over the years. Zweig (1963) pointed out that until about 1940, the life of an analytical chemist working in the pesticide field was a relatively serene one in which the chemist had to he familiar only with analytical methods for arsenic, lead, fluoride, pyrethrins, rotenone, and a few others. Just about ten years back, DDT and other organochlorine compounds were estimated by colorimetric methods (Sciu.ctcr et at. 1945) which obviously did not give precise information on the amounts and identities of the individual compounds present. Today's residue methodology is much more complex, and in order to cope with the new pesticides being introduced, the techniques are constantly being modified and improved. The wide variations in toxicity and persistence of pesticides, new or old, dictate refine ments in methods in order to differentiate and determine individual residues. Bearing in mind the complexities mentioned above and the fact that the spray history of most samples (excluding controlled spraying experiments) is unknown to the analyst, the availability of chromato graphic technique's which afford separation of a numLer of compounds in a mixture has made the multi-residue screening approach1 (U. S. Food and Drug Administration 1969 revision) die method of choice. Tho gas liquid chromatographic (CLC) separation with electron capture (EC) detection is presently the most popular analytical com bination for organochlorine pesticide residues. Multi-residue analysis involving GLC generally involves five Drilldpal steps: a) Sampling to procure a representative aliquot of the sample. b) Extraction of tho residue with a solvent (usually organic since most of the organochlorines (OC's) and many of the organophosphates (OPs) are fat soluble). c) Cleanup of the extract to remove interfering materials such as fats, waxes, pigments, etc. d) Analysis of the cleaned-up extract, generally by GLC-EC technique. ) Confirmation of the pesticide identity. Certainly there ore a great number of variations in carrying out these steps, depending on the nature of the pesticide and its substrate, 1 Editors note: See Buiucx, /. A.: Development of tbe Food and Drug Ad ministration's method of analysis for multiplo residues of organochlorine pesti cides ia foods and feeds. Residue Reviews, this volume. c wuinp MONS 084159 30 U M. Ritnolm the limit of detectability required, tnd the laboratory staff nod equip* moot available. It is beyond tho sc 5po of this review to discuss any of these methods in detail. Furthers >re, Gunthkh (1962) and Samuel and Hooces (1067) have reviewed his topic adequately. Accordingly, this review will deal niaioly with problems involving PCB's and re* latcd compounds. No attempt will t o made to review gas chromatog raphy for pesticide residue analysis. Bvjike (1963) hits discussed some practical aspects of this topic, while 7 nOMrsoN ct at (1969 and 1969 a) navo evaluated different gas chroma ograpliic columns for cldorinated pesticides. Before discussing the PCB's and their interference with pesticide residue analysis, some1 key referents in the English language on residue methodology are appropriat r. These arc listed alphabetically as follows: 1. Advances in pest control research, vols. 1-S. New York: Inter* science (1957 ct sea.) 2. A guide to the analysis of pcsth ides by gas chomatography, 2nd ed, S. T. Preston, Jr. Evanston, 11.: Polyscience (196S). 3. Analysis of insecticides and aca; icidcs, Gunther and Blinn. New York*London: Jnterscicncc (1957). 4. Analytical methods for pesticides, plant growth regulators and food additives, vols. I-V, Zweig. Nov York: Academic Press (1963). 5. Guido to the analysis of pcsticid; residues, vols. 1 and 2, Burch field and Johnson. U. S. Public Ht allh Service, Office of Pesticides, Washington, D. C. (1965). 0. Manual of methods for the determination of residues of Shell pesticides, Shell Chemical Company, Agricultural Chemicals Divi sion, New York (1969). 7. Official methods of analysis, Association of Official Analytical Chemists, 10th ed. Washington, D. C. (19G3). 6. Pesticide analytical manual, vols. I and II, V. S. Department of Health, Education, and Welfare, Food and Drug Administration, Washington, D. C. (196S). 9.Pesticide residue analysis handbook, Bonclli. Wilkins Instrument and Research, Inc., Walnut Creek. CnW. (1905). 10. Residue Review's, vols. 1-34. Gunther. New York: Springcr-Vcrlag (imetseq.) It should be emphasized that these references were all written prior to the knowledge that there was a possibility of PCB interference with Editor's notv: Thera ire now more then 05 books ooncerocd with pesticide residues including 60 that dUews analytic*! methodology in some (expects; eight oountrirs err represented by the authors. Cu.sTirnt, F. A.: Pesticide residues in the total cnvironmenl-HchaMe detection snd determination, mitigation, and legis lative control end surveillince programs. Pure and Applied Chem. 21. 355 (1870). ** mows oa'.ito Folychlorobiphenyk 31 certain pesticide residue analyses. In general, the methods described in theso references can be modified o cope with PCD interference. 11. Presence of PCB s in the environment Following the development of the EC detectors and their use with CLC, most residue chemists have observed unidentified peaks on their g.is chromatograms* Generally, there was no specific pattern to these peaks, hut analysts concerned with pesticide residues in wild life, especially in Europe (Houl.c 1965, Hamuson 1966, Holden and Mausdln J9GG), sometimes observ'd a particular series (with as many as ten or more peaks) of the tmi lentiticd peaks in their sample ex tracts* The materials giving rise to these unidentified responses occurred most frequently and in the largest proportions in extracts from aquatic raptorial species ol 1) rds and fishes. The general supposi tion was that these responses in re from condensation products of the metabolites of the org.mochlor nc pesticides, since they were gen erally observed when large amom ts of pesticides were also present. Rodl'un (J9G5) reported them to >e oiganoelilorinc compounds with fairly high chlorine contents, whic i no doubt accounts for their high sensitivities to the EC detector. lowevcr, Jensen (I960) was the first to state tliat these unident inet peaks corresponded to PCB com pounds, based on the analysis of a number of pike samples, an eagle, and human hair. Initially, the GLC and thin-layer chromatographic (TLC) nn'trrn* inti chemical inert:??:: were used to identify the unidentified peaks as BCD's (Je\si:> and Widmahk 1907). Other workers in Great Britain (Holmes ct al. 1967, Holden and Marsden 1967) and the Netherlands (Koeman ct al. 1967) also made early reports on the presence of PCB's in their fish and wildlife samples. At the Organisation for Econnn ic Co-operation and Development (OECD) Conference on "The Unintended Occurrence of Pesticides in the Environment," held in Scotland in September, 1967, the Euro pean chemists in particular showed much concern regarding the pres ence of PCB's in their wildlife samples and the possibility of inter ference with their organochiorine pesticide residue analysis. Up to that time, there had been no report on the occurrence of these mate rials in North American samples. However, in a December, 1967, report on organochlorine pesticides in seals and porpoises, Holden and Maiispen included a comparison of the amounts of PCB-type materials found in Scottish and Canadian samples. They reported that the levels of these non-hvdrolysablc materials were generally much lower in the Canadian specimens. Since that time RisEnnot;ci( et ol. (1968) have reported that the PCB's arc widely dispersed in the global ecosystem, while Reynolds (196$, 1969, and 1969 a) has found them in some Canadian wildlife samples. MOHS 064161 tt L. M. RSVNOLM Positive confirmation of the PCB's by gas chromatography-mass spectrometry (CC-MS) has no\ *been rfecported in Sweden (Widmmaawrxc 1967}, the Netherlands (Koem\n tt at 196...9..}..,....a..n..d.....i.n......t.he United States (Reichel HI. PCB interference with pesticide residue analysis The polychlorohiphenyls (X indicates the possible chlorine posi tions} and related compound: (polychlorinated triphioyls, naph thalenes, tcrprncs, etc.) have nuincrous important industrial uses but >)x arc not used as pesticides. Bccauso if their similarities In structure and properties to the DDT pesticide group, the PCBs---if present in i substrate--arc carried through the usual pesticide extraction and s recning procedures, and since they possess electron absorbing properties, wii] interfere w;dj CLC-EC analysis of orennochlorinc os wll as a number of the organophosphorus pesticides (Reynolds 19$ b). ' The reported CLC patterns indicating PCB interferences have shown marked resemblances wit;j 'Axoclor' 1254 and 1-00 (Jesses and Widmawc 1907, Holmes ef at. 1967, Ulynolos 1965 and 1909. and ICoemak et at. 1969). This type of interference wiih pesticide residue analysis is demonstrated ui;h u yt.uuiurd mixture ot organo* chlorine pesticides and a commercial PCB mixture (Arcelor 1254) in the chromatograms of Figure L The results confirm that the pres ence of PCBs in the sample extracts will cause interference with pesticide residue analysis under these or similar operating conditions. It should be emphasized that throughout this miew when the term "PCB" is used, this includes the polvchlurobiphcnvls and also the other closely related compounds mentioned above, however, the polychlorohiphenyls ore the most important from the point of view of interference with pesticide residue analysis. Under die CLC operat ing conditions, the chlorinated polyphenyls and other related com pounds >vith molecular weights greater than the chlorinated biphem Is will generally not be separated and observed on the gas chromato grams. Modification of the operating parameters such as higher col umn temperatures or changes in the liquid stationary phases are usu ally necessary to detect the presence of such compounds. It must be borne in mind that when high molecular weight com pounds are present, their peaks can appear on subsequent chromato grams and causo "secondary interference." This occunrer.ce can be recognised easily by the early emergence of unusually broad interfer ing peaks on the chromatograms, "Secondary interference'* is a term used by the author to imply that the interfering peak does sot have MQNS p , .4 ' Polychlc ubipheuylj 33 the same retention time as I hat >( the compound of interest under the*same operating conditions, "he interfering peak often originates from a previous injection and ca .not be simply repeated. Of course, if the elution lime is very long, the peak might be broad enough to escape detection and in such a case w ould not interfere. In contrast P JO i 4 [ > he 1 o\ i Fig. 1. 1*CB intcrfcrrnrr with organocl lorine pesticide residue analysis on four Eerccnt SE-30/SU percent on 00/KO mesh Chroniosorb \V, H* X 0' orosilicMo column. ChrutUMtocnm A; standard mixture of organochlorine pesticides; peuk numbers: 1 0-08 ng. of lindane, 2 TM 0.10 g. of nrptachlor, 3 0.10 ng. of aldriu, 4 - 0 14 ng. of hcpUehlor epoxide, S -- 0.20 ng. of DDE. 6 -- 0.20 ng. of Uicldrin, 7 * 0.30 ng. of DDD, and 6 * 0.50 ng. of DDT. Chromatogram B: 5 ng. of Arodor 1254 (the 14 milor peaks are numbered 1 to XIV). Chromatogram C. combine* tlon of above organochlorinc Oantlard pc'Ucidc mixture and Arodor 1254. Injector 250'C., column 200"C., detector base 250*0, N at 20 30 cc./n>inute to this type of interference, materials which have identical retention times will cause "primary interference" which is easily repeated by reinjection of the extract. With this form of interference a single, sharp peak is obtained, and in the absence of confirmatory and other precautionary measures, misinterpretation can occur easily. PCB-type interference falls mainly in this group. MGNS 064X63 94 L M- RirN'KM IV. Uses and properties on PCB's In order to understand how it Is p >ssible for PCB's to be present In wildlife and cause interference with pesticide residue analysis, it is necessary to give a brief description of some of their properties and uses. The PCB's arc produced and ma keted under a number of com mercial trade names, e g., 'Aroclor,' 'Cophen,' and 'Phcnochlor.' Koeman et ai (1969) reported marked resemblance between Aioclor 1260, Clophcn A60, and Phcnochlor I- P6. The 'Aroclor' plasticizers, a series of chlorinated biphenyls and chJcdnatcd polyphenyls, arc typical of these compounds. As stated bv ;he manufacturers (Moiuanto . Co. 1967), the 'Aroclor compound* are among the most versatile chemically produced materials available. They vary from mobile, oily liquids to white crystal* and hard transparent resins. Urey are non-oxi dizing, inert, permanently thcrmopl-stic, of low volatility*, non corrosive to metals, insoluble in water, and resistant to alkalies, adds, and corrosive chemicals. The viscous, norc highly chlorinated liquid and resin members do not support combustion and they unpart fire retardancc to other materials. The c ystallhie `Aroclor' compounds aro relatively insoluble but the liquJc and resinous compounds are soluble in most of the common organic olvents, thinners, and oils. Theso compounds arc used in protective coatings, as plactici2ers end extenders, ns sealers in wutcr-pnofing compounds and putty, iu asphaltic materials, printing inks, waxes, and synthetic adhesives. Liquid PCB's arc used ns dielectrics, as hydraulic fluids, in thermo stats, in cutting oils, ns extreme pressure lubricants, as grinding fluids, and as heat transfer media. Solid PCB's are used to impregnate carbon resistors and as sealers in impregnating agents for electrical apparatus. The properties of many products can be varied and improved by tho use of these compounds either as primary or secondary plasticizers. Further details concerning the diiletcnfc 'Aroclor* series, the grada tion of their properties, and the numerous possible applications can bo found in the manufacturer's technical bulletin (Monsanto Co. 1967). In the system of designation for the 'Arodors,' the first two digits indicate the type of material, while the last two digits give tho approximate weight percentage of chlorine in the product. For example, `Aroclor 1254 indicates a chlorinated biphenyl with approxi mately 54 percent chlorine, while 'Aroclor' 5460 indicates a chlorinated triphenyl containing about 60 percent chlorine. V. Possible modes of entry of FCB's into the ecosystem The means by which PCB's enter the ecosystem to contaminate fish and wildlife aro still not clearly understood There are however, MGNS Gtm64 four most likely pathways by wh ch PCD's enter fish aud wildlife; a) Because of their inciti css and versatility and consequent numerous applications, i. is quite conceivable that PCB's could be Hushed as was cs into rivers, lakes, etc. to pollute fish and other wildlife. b) There is a possibility the*: some contamination could proceed via the atmosphere wher wastes containing these compounds are burut c) Althougti it is unlikely, >omc type of Ullman reaction with condensation of aromati. halides with the aid of metallic agents such as copper to give rise to the formation of biaryls, cannot be completely ml* d out. d) Lastly, but not nccessari y the least likely, there is tlic possi bility that some companies arc using PCIVs in some insecticide formulations to increase t ic kill-liic. The idea of increasing the r< sidunl persistence of insecticides lias been investigated for some tin c and a brief resume on the moro important background work is in order. The carl)' investigations by Linjx>ci.st ct ai (1015) and Block (1918) indicated that the residual effectiveness of DDT was pro longed when the DDT was ap died in resins and paints, van tjel (1952) continued along these lines when lie increased both the effec tive peried and the toxicity of a DDT deposit on a glass surface by the addition of a small amount of couinaronc resin to a DDT solution in kerosene. Subseque ltlv, emphasis was placed on work involving the more volatile insecticides like lindane--a very effective pesticide but one which soon lost? its activity* because of volatilization. Sullivan and Hohnstein* (*953) in their experiments with the American cockroach, Pcriplonotti amcricana, found that lindane resi due remained toxic longer when it was compounded with Arocior 5460. They suggested that the chlorinated polyphenyl prevents crystal lization of the lindane and lowers the vapor pressure of the lindane in tho mixture, thereby preventing unsightly residues on surfaces ax well os extending the effective kill-life of the insecticide. Tsao ct of. (1953) obtained similar results against house Hies, Musca domesflea L. Continuing this work, Hohnstein and Sullivan (1953) con firmed these findings and described a general method for prolonging the residual effectiveness of volatile insecticides. The method consisted of preparing concentrated solutions of the pesticides in the film-form ing polychlorinated polvphcnyls. A Monsanto Co. Technical Bul letin (19G5) states that because '"Arociors* in formulations 'trap and hold more volatile ingredients, they make volatile insecticides and repellents 'last longer' in residual activity." Attempts to determine whether litis idea had been put into practice have so far been unsuccessful. However, if the PCB's are being mrd MQNS 064165 9$ i- M. KsrcMM in pesticide formulation, then Ms coupled \rith the numerous other uses suggested io a later Mouse \to Co. Bulletin (1967). might cer tainly explain their presence in wildlife tissues and other samples. There is an obvious need foT clarification of the sources of PCB's in fish and wildlife, and this could probably be accomplished using tracer techniques. VI. Toxic ty of PCB's Tho PCB's were studied as c.uly as 1SS1 (Schmedt and Schultz) and were in wide use bv 1930 (Penxinc 192)1. Later Jones and Auden* (1936) reported tlint the compounds were toxic. Creexberc it aL (1939) reported that PCD' and polychlorinated naphthalenes caused the deaths of three workc;s. Men employed in the production and use of PCIVs developed acne- ype skin cruptons (Soiwaaiz and BatUjOW 1942. ScnwxHTZ and Pres 1913, Scinv.vETZ 1943). Mu,i.cn (1914) reported that *CB's caused pathological changes in laboratory animals. Brown* (19,7) warned about the toxicity dan gers of the 'Aroclors' when there was a su'Sgtsrion that one of the vtrocJors' bo used as the melting point bath lie-id in preference to the customary' mffuric acid. Later McLavchlin et til (1963) found that Aroclor 1242, besides being toxic, produced teratogenic cJTcct.i in chick embryos at lower dosage levels. Risreroucn et a!. (1968) reifrrafH that PCB's along with othci vlnujui.uru biocides, such as DDT, could account for a large port of the aVemition in calcium metabolism that has been observed in manv species since the second world war. With high dosage of PCB`s, hydropericards have been observed in quails ( Koemax et el. 1969). * It has been stated (Memento Co. 19671 that at ordinary tem peratures the `Aroclor* chlorinated polyphenvjs d? not present indus trial toxicological problems. Howr\rr, caution uu advised-in handling theso materials. 3 ho hazard of potential toxic exposure varies with tho volatility of the compounds: tho lower chlorinated, more volatile ones present more of a potential problem from the standpoint of both inhalation and skin contact. At elevated temperatures, the use of PCB's requires very effective and efficient exhaust ventilation systems. It has also been stated by the manufacturers tb.it "tests on animals indicate that the maximum safe concentration of v.-.por is in the range of from 0.5 to 1.0 milligram of the lower chlorinated 'Aroclor' plasti cizers per cubic meter of air. The threshold limits (maximum allow- ablo concentration for an 8-hour working day) set by the American Conference of Government Hygienists are 1-6 mill: cram of the lower chlorinated `Aroclor' compounds per cubic meter c: air and 0.5 milli gram of the more highly chlorinated compounds, such as 'Aroclor 1254, per cubic meter of air." MONS ?) ..J re . . '.:rt bn* a the v to -land '<ctt ;W) li M .Hum . Aend - : been ' trm* ' Indus* mUing n with ' volatile . ;vint of tke use citation . -animals '* range ptaslb i allow* ; Inerican lower . 03 milli. 4 ' `Aroclor' Polychlorobi ibeuyU 07 However, as ltrsinnoucii et al. (1968) pointed out, only relatively small amounts of chlorinated hydvoi ubons arc required to cause en zyme-induced breakdown of steroid;, thus making irrelevant much of the p.p.m. approach to pollutant ecology based on toxicity data alone. There is no doubt that further . esenreh in this area is urgently needed. VII. Analysis of pesticide rcsidi es in the presence of PCB's PCB's are of interest to analysts for three main reasons: a) The compounds arc toxic. b) They arc widely distributed ; nil their uses are increasing. o) They interfere with CI.C determinations of organoemorine and oiganophosphorus pistieido residues. The first two reasons have been dealt with earlier and therefore need no further elaboration. Aecon ingly most of the remainder of this review will be oonermed with he nnalvsis of pesticide residues in the presence of KdVs. Aho tin present methods of estimating the amounts of PCll's will be discuss* d. As mentioned earlier, it was emphasized at the 1907 OF.CD confer ence that Ptill's were in fact bein' detected in fish and wildlife, especially in Europe. The conference among other things served to alert other chemists and scientists to (he problems of PCll's and their interference with pesticide residue analysis. Since the discovery that PCB's arc contaminating fish and wildlife and that they interfere with organochlorine pesticide nnalvsis, very little has been published on how to cope with these interferences and how to differentiate tho PCB's from pesticides. Based on preliminary work, Jensen and YVidmark (1987) suggested a nitration technique based on the inert ness of the PCB's compared to the relatively easier nitration of the pesticides. Risedhovcii et al. (19CS) reported the use of this method, out Reynolds (1909 b) pointed out that nitration is not a suitable approach since some pesticides (lindane, toxapenc, Strobanc, etc.) apparently will not nitrate, while some of the PCB's appeared to be nitrated under the suggested conditions. In addition, there is the problem of further complication from the interference of the nitroderivatives formed, especially when the DDT-group pesticides are present in large amounts. To avoid the above complications and at the same time facilitate the chromatographic interpretations and afford a means of estimating tho PCB's and pesticides independently, Reynolds (19GQ b) intro duced a Florisil separation scheme. Koe.man et al. (1969) have also reported a similar Florisil column technique to separate the PCB's from the pesticides. 08`*V<>7 mons M L.M Rctnolpi In Reynolds' method, the pa tially cleaned-up sample extract con taining the pesticides and PCE', is placed on a Florisi! column and tho PCB's arc eluted first with ii-hcxane, followed by elution of the pesticides with an ether-hexane mixture. Originally, this technique was intended to serve as the f nl cleanup step, as well as effecting separation of the PCB's from (he pesticides. As will be explained, the method has since been sligl tlv modified (miniaturized) to serve mainly as n separation technique Of the many pesticides investigated, only hcptachlor, aldrin, and tire )DT metabolite p.p'-DDE arc eluted with the PCB's. With die exception of p.p'-DDE, these do not present difficult problems since chemical reactions (epoxidntion, hvdrobromination, etc.) can be used to differentiate hcntachlor and aldrin from tho PCB's. Furthermore, these two pesticides are more frequently found as the more stable epoxy products which arc separable from the PCB's by this scheme. p,p'-DDE on the other hand presents a more difficult problem on account of its chemical iner ness. Its greater stability resembles that of the PCB's. and the comj otmd is not amenable to any simple and convenient method of sirut two modification to give a product which is readily detected within the usual CLC-EC operating param eters. Of course the ideal situation would he a convenient addition of onb mole of hydrochloric add o the p,p'-DDE to form p.p'-DDT while tho PCBs are not affected. This would afford confirmation and quantitative estimation of p,p'-LDE in the presence of PCB's. Gen erally under such circumstances it would not be necessary to do an additional Florisil separation. Tlx* amount of p,p'-DDE present could bo estimated indirectly from the p.;/-DDT produced since, ns will bo discussed later, the p.p'-'DDl (and p.p'-DDD) can be separated from the PCB's by the use of highly polar liquid phases. It should be emphasized that although p,p'-DDD and p,p'-DDT are mostly separated by tho polar phase columns, without introducing a Florisil separation the earlier emerging pesticides are superimposed on the PCB's and lienee a separation is necessary to identify and to quantify these latter pesticides. After the Florisil separations of PCB's and pesticides are made, tho two cluatcs arc chromatographed separately on the SE-30/QF-1 column and compared with appropriate standards for quantitation. This is normally followed by confirmation of the identities of the pesticides. VIII. Confirmation of pesticide identity Despite the separation of the PCB's and their elimination as fourees of interference, the non-specific nature of the EC detector HONS 064160  Polychlorobiphcnyht 39 makes it necessary to confirm the ^entity of the pesticides by addi tional techniques. The sctjmncc usually followed by our laboratory is; a) Injection of the pesticide oluafe onto a more polar liquid phase column (c.g., polyester such us DECA or DECS). Typical Fig. 2. Separation of PCB's ond orgnnochlorinc nrsticirfw en polar phase column (five percent DKCS/two percent IIPO<). Cororeitogram A: standard mixture of organochlorinn pesticides with fame ac.;-jnts as in Figure 1; peak numbers: 1 * heptacnlor and nldrin. 2 3 heptachlor xfde, 4 - DDE, 5 - dtehiu|LwQ - DDT, 7 DDD. Chromatogram r5 ne. of AroeJor 1254 (the Tl m.qor peaks a:- numbered I to XIV as in chromatogram B of Figure 1, assuming that the order oi elution Is unchanged). Chromatogram C; combination of c::<mochlorine standard pesticide mixture and Aroclor 1254. Other CLC parameters as in Figure 1 separations of pesticides, PCB's, and a mixture of the two groups arc shown in Figure 2. The reversal of p.p'-DDD and p,p'*DDT and their separation from most or the PCB's is note worthy and quite useful. One drawback is that peak No. 13 of Aroclor 1260 interferes partially with p.r'*DDT. Other use ful information can be obtained by study of the retention times MGNS 084169 O 40 L. ! i. Reynolds of individual pesticide? For example, this approach affords separation of the three main BHC isomers. The technique is especially useful for ruling out the presence of pesticides in* djeated as possibly pro; ?nt by Use. SE-30/QF-1 column. How ever, tho retention tim on two or more stationary phases cannot be regarded a: independent parameters of identity (RonrNSON* 19o7). b) Dcrivatixution and use of characteristic CLC retention times of the derivatives. As reported earlier (Reynolds 1969 a), our i laboratory has incrcasin dv utilized chemical reactions for con firmations of pesticide residues because the samples to be analysed are generally mall and tire amount of residue is in* sufficient to allow effee ivc application of infrared, mass, and other spectroscopic met ods. Tho derivntlzntion techniqu i has been used by a number of work ers (Cuntiieii 1962, Klein ct aJ. 1964, JIammence et ol 1965, Sans 1967, Duffy and Wonc 1907, C sado unc and Wanless 1963, Cociitune and Chau 19G3, Ciiau 19G9, C iau and Cociihank 19G9, Wifncix and DuitKE 1969) and is gaining i i popularity- Success of the technique usually depends on the speed c derivative remaining lipophilic and i therefore extractable with the organic solvent (usually hexane) for i adirect analysis bv the usual CL' !-IC method. A number of chemical renc ions is available, but two of the more ! bread-spcctiuiii t\ pcs that arc quite ucfui for t!ic pesticides generally found In wildlife arc: i (I) Reaction with ethanolic potassium hydroxide (mainly dchy- drochlorination) to gve products wit!) shorter retention times. This is effective for DDT, DDD, and their isomers, aj well as - and y-RHC; the 0-isomcr is not affected. (H) Reaction with hvdrogvn bromide/acetic anhvdrido reagent to give bromohydrin or bromoacetoxy derivatives with longer retention times. This reaction has been found useful for hep* tachlor, aldrin, hcptachlor epoxide, dicldrin, and endrin. c) Tldn-layer chromatography. In spite of certain drawbacks with * TLC for confirmation of small amounts of pesticide residues (Reynolds 1969 a) tiic technique is still valuable for the con* finnation of DDE. TLC can be quite useful also for some group separation, as an ancillary cleanup technique, and for semiquantitative estimation of some pesticide residues. IX. Identification of PCB's in samples Data obtained by our laboratory in the course of work conducted for The Canadian Wildlife Service have demonstrated that PCfi's are present in some but not all species of Canadian wildlife. Undoubt* O MONS 084170 \ in* . Ilnw* `use* :,nlity time* . ,i, our r ron , to be '.f it In- and * -f work- *u, Sans .CIAANB \<xs and ihnifjue itlic and uric) for : the more t generally ^nly dchy* retention -tomers, as ! reagent itli longer , ,,ilforhep- * 'ndrin. ' tael;* with V residues *>r the con- ; '> for some ( V: i.and for t ' conducted i / that PCB's v ta Undoubt | , | j t | i I : , ! : j * | ! 1 i PoIychlorobtphenyU 41 edly the presence of PCB's h s complicated the pesticide residue methodology, but this complication cannot be avoided if meaningful restilts ate to be obtained. Since not all samples contain FCBs, it would be unwise to do a Florisil separation on all extracts before having some indication whether or not the separation is necessary. Accordingly our laboratory use:; the approach described below. The sample to he analysed ;s extracted, eleaned-up, and assayed using the SE-30/QF-1 column, depending on the EC results, a deci sion is made whether or not to make a Florisil separation and chrck further for the presence of FCBs. This decision is based on the as sumption that if there are no apparent ;>,//-DDD and p.p'-DDT peaks, then the presence of PCU's would not be expected. The DDD-DDT combination is chosen as the criterion because peaks eight and ten, hvo of the larger peaks in A rod >r 1254 and 1260 have identical reten tion times with p.p'-DDD and ''.p'-DDT, respectively. Also, the FCB components giving rise to peals eight and ten are less likely to be metabolized than the earlier merging compounds. lienee, if PCB's (125-1 or 1260 paUrrti) are picsent. peaks should show up giving apparent ;>,p'-DDD and />.p'-i)DT values with the EC detection system. Other useful information regarding the presence of PCB's can bo obtained from the initial gas chromatography. If the* CLC pattern (prior PCB separation o:i rlvvvt high "apparent" p,;/-DDE with little or no p.p'-PDD and p.;/*DDT present, then all or most of the "nppun nt" DOF is probnblv "true" DOF. This is because peak five (the peak which interferes with p.p'-DDE) in the common PCB commercial mixtures (Aroclor 1254 and 1200) is relatively small compared to flic DDD- and DDT-interfering peaks (eight and ten) as shown in Figure 1. This rule has been borne out by TLC confirmation of DDE in a number of such eases. As mentioned above, the two most commonly found PCB types In wildlife samples resemble Aroclor 1254 and 1260. Although these two Aroclor* arc quite similar in mam* respects, certain differences in their GLO patterns, as shown in Figure 3, can be used to identify one from the other. With a higher chlorine content, Aroclor 1260 shows about 37 major peaks fSE-30/QF-I column) compared to 14 with Aroclor 1254. Besides this, one other obvious major difference is the peak-height ratio of peaks ten and 13. This ratio has rough values of 9.3 and 1.0 for Arorlors 1254 and 1260. respectively. Additional information regarding the PCB mixture present in a Sample can be obtained bv comparisons of other peak-height ratios of the PCB standards and the TCB's in the sample. However, it must be borne in mind that in practice one might be faced with complex mixtures of TCB's rather than a single, specific mixture. In such cases an average value seems to be the best compromise. The method of estimating l'CB's described below attempts to take this into account. MON* 0841? k tt L. M. fUrcoua Although most of the early reports on the presence of PCBs in samples indicated the Aroclor 125-1 CLC pattern, more recent work by Koeman ct al. (19C9) and he author's laboratory has indicated that a proportion of the specimens docs contain the Aroclor 1260 CLC pattern. This apparent pn dominance of the Aroclor 1234 tvpc might have been due to its availability as a standard and lack of tho Aroclor 126U type iu the early developmental stages of PCB methodology. The CLC profiles of a number of commercially available PCB mixtures were determined using the SE-30/QF-1 column. These are shown in Figure 4 and incii ate that tire more highly chlorinated o i i X i 1 ( O Minutes Fig. 3. Comrnrison of Aroctonc 1254 and 12C0. Ckramatogram A; 3 of. of Aroclor 12154; tho 14 major peaks are numbered I to XIV as in chroma togram ft of Figure 1. ChtomatnpMtn 0: 5 c. of Aroclor 12P0; the 1? major peaks are numbered I to XVII (the tarly peaks correspond to theta in Aroclor 1254). CLC parameters as in Figure 1 biphenyls (Aroclors 1254 mid 1260) arc easily detected with the usual operating parameters. On the other hand, the compounds of the lower chlorinated mixtures (Aroclors 1221. 1232. and 1242) and the higher molecular weight mixtures (eg., Aroclor 5461' arc less responsive and arc, therefore, more likely to go undetected under normal operat ing conditions. Apparently, the lowered sensitivity is due to low chlorino content in the first group and to high molecular weight with resultant long retention times in the second group. In both eases, therefore, higher concentration would be a prerequisite to ensure detection under normal conditions. This, os well as the possibility of metabolism of the less highly chlorinated biphenyls (Koemas cf HUNS 084172 o Polychlorob phenyls 43 at, 1969), might explain the grncra absence or rarity of these com pounds in wildlife samples. It must not be overlooked, there ore, that in the presence of large amounts of the lower chlorinated biuhcnyls (e.g., Aroclors 1221, 1232, t. < 0* 17 to > usual lower higher pusive 'tywal elilo* 'tl with ' roses, rmuro nihility imam cl Pig. 4. CLC profiles of lh more popular Arcelor mixtures under normal analy tical condition*. Note: Ail peak numbers correspond to those of Aroclor 1254. Chomatograms: A - 5 w*. of Arodor 1221, ft - 5 ng. of Arcelor * 1232, C * 5 ng. of Aroclor 1242, D 5 ng. of Aroclor 125-1. 5 ng. of Aroclor 1200, and F - 5 ng. of Aroclor 54C0. CLC parameters as in Figure 1 and 1242) and negligible quantities of the higher chlorinated bi phenyls (e.g., Aroclors 1251 and 1200), different criteria would be necessary to delect PCD interference. To date, this condition has not been encountered in Canadian wildlife samples. MONS 064173 44 L. M, lUCTNOLM As might be expected from t' e complex nature of the PCD mix tures and the chemical inertness of the individual compounds, the confirmation of identities of these materials is much more difficult than with tho organochlorinc pcstirides. Thus, in the absence of a mass spectrometer, confirmation of the PCB's is mainly by their CLC retention times and patterns on the mixed and polar phase columns in conjunction with their non-reactivities with the two general reagents used for the orgnnochlorinc pestle ides. The prior separation of the P 'B's from the organochlorinc pesti cides by the Florisil technique u.so aids in the identification of the PCB's. X Eslimaton of PCB's Since the PCB's are themselves toxic, attempts have been made to estimate the amounts present n samples. It should, however, be recognized that only rough cstim itc-s can be made since pure stan dards of the individual compounds in the mixtures are to date unavail able. The situation resembles th t of toxaphene estimation, but is of greater complexity. Koeman ct ah (1069) based their PCD estimation on the peak of pitenodor DP6 having r, (relative retention time with dieldrin -- 1 under his operating conditions) equal to 1.45. ftrsKanoucH ct at (1560/ estimated the FCBs on the assumption that they* have similar EC responses to ;>,;/-DDE and applied a factor to fit the assumed 54 percent chlorine content of the PCB's. Jensen* ct al. (19G9) re ported estimates as the sum of all the PCB components. The author's laboratory uses a method very similar to Koeman's with the exception that an average based on two peaks is usually employed. Should the two values before averaging vary to any extent, additional estimations arc made using other peaks, and all the results are averaged. In the case of a few samples, the PCB level was ob tained by averaging results from all the major peaks in the mixture; however, the use of peaks eight and ten only has been found to give equally satisfactory results. N'ote that results are reported as being based on Aroclor 1254 or 1260 depending on the overall CLC pattern. Peaks eight and ten were chosen because of their stability (see section on identification). In a later section the above points are illustrated by analysis of resin powder taken from a fish hatchery trough. Te total PCB remits obtained by the method described may be slightly higher than the actual values because the eariv emerging PCB peaks (mainly one, two, and three) are usuallv absent from tho chromatograms of sample extracts. However, this should not a/Tcet tho overall results greatly since these peaks represent minor compo nents In the mixtures. Furthermore, there might be compensation, since no attempt has been made to apply recover)' correction factors. MOMS 064174 Polychlor tbfphcnyb 45 The method of estimation described above appears to give a rea sonable estimate of PCB contain nation b.iscd on eon:::HTcial PCB mixtures. For absolute ineasurcn ent of PCB content :t would be necessary to prepare stundaids fir tlic individual PCB components, and, even if these were available, the determinations would be complex and cosily. Considering our present limited knowledge of total PCU toxicity and our even ycater ignorance about the toxicity of the individual components of he mixtures, it is doubtful whether such accurate determinations wo ild be meaningful at this time. As stressed earlier, the most urgent i ;cd is for toxicological investigation in this aica to indicate whether some of the PCU compounds are more toxic or have greater snbkthal effect than others, as observed with the BJiC isomers. At that point it would become essential to identify and estimate accurately : pecific individual compounds in the mixtures. XI. Separation of PCB's fren orgnnophosphorus compounds by tho Floi isil technique A limited amount of work lias been carried out in our laboratory to determine whether the Florist column technique is applicable to the separation of the PCB's from the nrganophosphorus compounds. Preliminary results on tho>c tcstid (photate, diazhmn, round, malatliion, parathion, methyl Trithion, ethion) indicate that they arc not eluted with the PCB's by hexane, and can therefore be separated. In comparison to the organoehlor ne pesticides, tlic org.mophosphorus compounds generally require larger volumes of the ether-hexane mix ture for elution from the FlorUil column, most likely because of their more polar nature. As with the organochlorinc pesticides, the presence of PCB's in a sample extract will interfere with some of the more common organophosphates when the EC detection system is used. However, with the use of a dual detector (EC f- phosphate or thermionic) connected to a dual-pen recorder, tlic effluent from a single injection containing PCB's and organopliosphates can he split and dillrrcntintion made as shown in Figure 5. Like the organocltlorinc pesticides, the PCB's are not detected on the phosphate detector. Nevertheless, in the ab sence of a detector which is specific for phosphorus, the Florisil col umn technique can be used to separate the PCB's from tlic organo* phosphates to facilitate the analyses. XII. Residues of organochloriuc pesticides and TCB's in Canadian wildlilc Following the approaches outlined, tho author's laboratory has analysed a number of Canadian wildlife specimens for residues of MOMS 004175 L M. Rktholo* FI*. 5. Differentiation of Aroclor 1251 and nrganophosphcrus pesticides usin| dual detectors and efllunt ar*lt ChrnmrtfnpMm A- orjnnnpHojphont standard poticide mixture peak numbers 1 1.75 ne. of phoraic, 2 2-0 ng. of diaiinon, 3 b.O wg. of ftoimel, 4 13.0 ng. of tnataOiion. 5 - 5.0 g. of mruthion, 0 15.0 ng. of methyl TritJiion, and 7 - 10.0 ng. of ethion. Cliromatogrtm B: combination of organophospliorus mu* ture (chromatogram A) and 10 ng. of Aroclor 1254 numbered I to XIV as In chromatogram B of Figure 1 (a compromise of the E.C. response is necessary to obtain maximum response on the phospltorus detector). I* phmjtliorus detector ind hC - electron capture detector. Column four percent OV-100/st.v percent OV-210 on 60/60 n>c*h Chrotnoiorb W (AW); other CLC parameters as In Figure 1 organochlorinc pesticides and PCB's. Some of tho data on aquatic birds from Western Canada are given in Table 1. The inclusion of these tabulated results, which represent only a minor portion of the total number of samples analysed, is intended to illustrate the types of analytical problems created by the presence of PCB's. and to incli* CAto potential errors due to high levels of PCBs in samples. Referring to Table I, some general remarks arc in order: 1. The greater portion of the apparent DDE in samples is in fact DDE. This is predictable from the comparatively smaller amounts of apparent DDD and DDT, and has been verified by TLC. 2. A large proportion of the apparent DDD in the samples is due to PCD's, However, DDD is present in some samples. HONS .*6 dnia J- i Mil* XIV !nn ubW -,'jatte a of i the ' hpc* i ittdi* 9 fact ounts a due ! I . PolycMi -oblpHcoyl) 47 3. The effect of TCB conlumina ion on DDT values is less marked than in the ease of ODD, hut it is still substantial. 4. The apparent HE values are in most eases duo entirely to the pesticide. This is somewhat ii congruous with the rest of the data since peak four of the cornu crcial l'CB mixtures docs interfere with 1112. However, this anomaly may be explained on the basis that the rea component gi\i ig rise to peak lour is degraded ex* tcnsivc'iy in the birds nu taboh.' processes. 5. Based on all of the PCH esi mates in wildlife samples noted to date, including those in Tabl : I, the following general trends are evident: (a) Aquatic r.iptorials gener lly contain higher residue levels of pesticides and l'CB's than oth r wildlife species. (b) High levels of PCU s ai** found only in the presence of high levels of organochlorinc pcstcidcs (the resin powder mentioned below is an obvious cxceplio ) but high levels of organochlorinc pesticides arc not neccssnrilv iccompanu-d by high levels of FCB's. (c) Tho most abundant PCU txpes detected are those which show Aroclor 1251 and 12G0 path ns and, therefore, fit well uith the od nu-thod of quanlilu ion. However, it should not be over* that with the present l.siduc methodology some other PCD* typo compounds might go umYfcctcd. 6. It i$ important to measure . loisturc and fat content of samples in conjunction with residue levels. This ullim fo u porting on a wet-, drv*. or fat-weight ban's. However, caution should he used when reporting residues in wildlife samples, for example, on a fat basis when the fat content is very low. Such figures can be inaccurate ns well as highly misleading. The gas chromatogram of a typical sample showing the presence of PCB's is given in Figure 0. It indicates the Aroclor 1260 pattern and was obtained from a duckling found dead in the Toronto area in the summer of 1969. A good example of PCB's showing up in unexpected places oc curred recently. A wildlife biologist was faced with the pioblcm of fish dying in a hatchery for no apparent reason. He scraped some of the resin powder from the hatcherv trough and found, surprisingly, that experimental fish were susceptible to even a dilute solution of tho powder. He submitted a sample of lire resin powder to the author's laboratory, and upon analysis a typical GLC pattern of PCIVs (.Aroclor 1254 type) was obtained. Tins is shown in Figure 7. Using tho meth odology described earlier in this review, the sample was found to contain TCB's but no pesticides. Based on calculations from 11 indi vidual peaks of Aroclor 1251, the FOB concentration was estimated at 35 p.p.m (range 25 to 46). Using the average results based on peaks eight and ten only, the TCB estimate was 29 p.p.m. This is i I Mr I t S T*rB O SNOW sjXuai{d!qoMmo.((oj Table I. (contfnaed) Descriptioa of specimen* py- Did. DDE* drin* p,p'-DDD Before (apparent) After 7<* p,p'-DDT Before (apparent) After %* HE Before (apparent) After PCD* %d Sample 1 ares 0 Sample 2 area 6 Sample 3 area 6 Sample 2 arm 7 Sample 1 area S Sample 2 area 9 24.0 11.3 13.7 13.5 3.7 6.3 9.1 0.42 0.19 0.74 0.07 0.06 O.fiS 0.07 0.33 0.07 1.63 0.07 0.12 0.09 0.00 0.27 ND 1.70 0.05 XI) 00.-. 0.03 Pi 0 104 040 19 52 0.1S 0.30 0 OH o.os Oil 0.01 0.07 0.10 0.23 O.OG 0.02 0.03 0.01 0.C5 57 77 09 33 IS 22 70 0.15 0.10 0.05 0.02 0.02 0.02 0.03 0.12 Trace* 0.03 Traee* T00r..a00m11* 83 -- 100 -- -- 52 44 3.41 1.93 1.09 0.57 1.38 0.53 0.33 These specimens ere from western Canada (Veumkk* and Hetnoi-os 1970). These are "Before rCB-Klorisil separation'' values and ar.; likely to include PCII contributions. The "After" values (which do not change significantly from the "Before'' values) are not gi"Cn l>crnusc tin; PCD peak five (the DDE-interfering peak) of Aroclor 1254 or 1200 is not separated from DDE liy this method, bu% as discussed earlier, the l'CD contrilmtioua to the DDE values are expected to be relatively small compared to the contributions to DDI) or DDT. These arc "Before" values. The "After" values (not given arc not significantly different from the "Before" values since there is no direct PCD interference. However, in the |rcscncc of high levels of DDE, low levels of dicldrin will be masked. In such cases a separation (e.g., PCU-Klorjj.il teclimiue) is i.ccissury, auJ the "After" value would he reported as the dicldrin level. 4 % B After v:*hic_ ^ jqq aDCj indicates the percentage of tlie total apparent pesticide level that was actually due to the pesticide. Before value Values (p p m ) based on peaks right and ten of Aroclor 1254. / ND none detected " <0.0001 p.p.at. Trace -- <0-001 pp.ru. n U V. Rsynoum .Fig. 6 Typical sample indicating tl e presence of PCB's of the Aioclor 1260 typo in a duckling from (lit Toronto area, Chromatogram A: 5 ng. of Arodor 12C0 mimlrcred 1 to WI1 ns m chroiiinU>ifiam B of Kizure 3. Chromatogram U: the erpnv lent of 0.35 nig. of duck sample (hexane fiortion of 1'loHsil split). N<to tbo DUE contribution to PCB peak V. CLC parameter* at in Figure l Fig. 7. Resin powder extract indicating the presence of rCB'i of the Aroclor 1254 type. Chromatogram A: 5 ng. of Aroclor 1254 numbered 1 to XI'' at in chromatogram B of Figure 1. Chromatogram fl: The equivalent of 0.02 mg. of resin powder extract (hexane portion of Florisil split), numbered 1 to XIV as in Aroclor 1254. CLC parameters as io Figure 1 MONS 0B4179 t I . 1200 *c- o* 0. MM V. t I * Aroelor 1 to XIV dent of *l split), figure 1 t Polyddi robiphcnyl* SI an interesting example of PCB': causing contamination as a direct resuit of industrial application. With regard to the Florist! lvcliniquc for the separation of PCB's from pesticides, one important nodiOcation to tlic original mctliod (Reynolus 1909) is now used re ntincly in the wildlife studies. Origi nally the scheme was designed o accommodate simultaneously l>oth tlo cleanup of the sample extract and the separation of PCB's. How ever, os pointed out earlier in his rcvicxv, not ull samples contain PCB's. Consequently, for genera samples, to avoid unnecessary split ting of all sample extracts (eacl split doubles the number of eluates to bo chromatographed), a noriial cleanup including a Florisil col umn, but no dillerential elution, is conducted. The FIorisil-PCB sepa ration is then carried out on tin cleaned-up extract, if it is required. Under these conditions smaller columns have been found to be as efficient as the larger columns u cd in the original method, and there is a substantial saving in the amount of reagents required. Details of the modified procedure arc as rolIows: A glass column (M cm. X 1 cm. .d. having a 50-ml. reservoir on top) is packed with :JO cm. (~10.7 g.) jt Flomil (60/100 mesh, Floridin Co., pesticide grade, slriirj at ioO'C. intil ready for use) and topped with a 2-cm. layer of anhydrous Na,SO . The sample extiact of about 5 ml. (n-hexanc) is aiidcd to the eel imu. The lr<t elution which removes PCD'*, brpi.icMor, nod DI>E, is effected with 0U mJ, of n-hcxajic (Nanogrude, Mallnickrodi). The fwSiak'dr.g pc;Uc:Jus arc then eluted witli 40 ml. of 50 percent ethyl eth-ir in hexane. Note that in filling the columr i, (he Flomil is packed down by gentle tapping, and (he sample extract k added to a dry column, i.c., no pre wetting. After the first elution the receiver is changed as soon as the last of the hexane meets the NaSO,. It should be noted also that with one batch of pesticide grade ldomil, some PCB peaks (two, six, nine, 11) showed partial elution in the second- eluate. These, however, arc com paratively minor peaks and do not interfere with any of the common organochlorlnc pesticides. As there are differences in batches of Floiisil, the procedure has to be checked out fully prior to application to actual samples. Modifications of volume*, etc., may be necessary to effect the desired separation. It is likely that adsorbents other than Florisil, c.g., silica gel nr alumina, will give similar separation of PCB's from pesticides but these have not been investigated to date. Acknowledgments Work in connection with this review was supported by funds from the Pesticide Section, Canadian Wildlife Service. Ottawa, and from the Province of Ontario through the Department of Trade and Devel opment. The writer gr'tefuUv acknowledges helpful suggestions of Dr. S. C. Reid, Director of Organic Chemistry Department, Ontario *ONS I Si Li M Rktnolm Research Foundation in prepar ng this review for publication. The technical assistance of Terry Cc >pcr and Sandra Takacs is gratefully acknowledged. Table U. Chemical designatl -ns of pesticides mentioned in text Pesticide Chemical Dame aldrin *y-T>ni) (TDK) pS-dvk p,p'diyt diisinon dleldrin elhion beptachlor bepCachlor epoxide lindane (y-BIIC) mtilthion methyl Trithioa paralhion phorate (Thiinct) Roane) 1,2,3,4,10,10-hf achloro* 1,4,4ft,.'S,8,Sa-hesahydro*1,4-ride, re-5,8-dimct itnoiiAphthalono 2,2-bis(p-cl*loro >licnyl)-l,l-(lirliloroclh>ne 1.1-dchloro-2,2 biii(p-rhliropUcnyl)etliylcne 1.1.1-tricliloro-i 2*bis(p-rl)lorophcnyl)elhan 0,0-dicthyl-(M ,-iiopropyi-4-mctbyMV-p)Timidyl)-pboa- pliorolhioate 1,2,3,4,10,10 he :acbloro-S,7*ciuixy-l,4,4a-5,0,7,A<8a-oct*- hydro-l,4-rru >,fio-;',8-dimchanonaphUilcre 0,0,0\0Mctrm Uiyl-S.S'-inethylcne biipboapliorodithioato l,4,A,0,7,A,8>lie| tAchloTO-3a,4l7,7a-telraiiydro-4,7-cnd' methnnoinde <e tAchloro-2,^-epoxy-3a,4,7,7a-telrahydro-4l 7*mcthanoim ftiie vl,2,3,4,5,U-hc achlorocydohexaoe 5-{l,2-bis(ctltox v carbonyl)cthyi|0,0-dimcthyl phospborodi- thioate 0,0-dimctliyl C-ip-enioropncnylthio; methyl phoepliorodi* thionte 0,0-dicthyl ()[> nitrophcnyl pliofiphorothioate 0,0-diethyi 6'-< thyltliio) methyl phosphoroditbioato dimethyl 2,4,5-lmblorophcnyl phoaphorotliionate Summary Since I960, PCB's have been detected in fish and wildlife, espe cially in Europe and North America. Contamination from industrial wastes via the water ways appears to be the main source of PCB's in aquatic species. The PCB's have many important industrial uses but are not utilized as pesticides. Due to their similarities in structure and properties to the organochlorine pesticides, the PCBs tend to interfere with accurate GLC-EC determination of organochlorinc and many organophosphorus pesti cides. In addition to their interference with pesticide residue analysis the PCB's are themselves toxic so that their quantitation is desirable. A method for recognising the presence of PCB's in samples, sep arating them from pesticides, and determining the pesticide levels accurately is described. Simultaneously an estimate of total PCB con tent is afforded. MQNS 084181 Polychlorc bipheoyls 53 The residue data of some Cl ladian aquatic birds indicate that high levels of PCB's arc found only in the presence of correspondingly high levels of the DDT pesticide group. On the other hand, high organochlorinc pesticide levels are not necessarily accompanied by high rCB content. Further research on toxicitv anl sublclhal effects of PCB mixtures and their individual components is required. If particular components arc shown to be more toxic than ( dicrs, refining of the PCB quantita tion methods will be necessary Rlsumd* Analyse dc rlsidus dc pesticides en presence de diphenyls polychloris Depttis I960 ties diphrnvls pilychlores (PCBs) ont etc detect^ dans fes poissons rt le gibier, >articu)ieremrnt en Europe ct en Amcriquc do Nurd. 11 appurait pie lu presence de PCBs dans la faunc aquntiqoe suit duo principa cmrnt a la contamination des cours d'eau par des dechcts imlusti icl:. Los PCBs sont utilises pour un grand nombro dc procodec imlustricb importants, mais ils nc sont pas appliques coniine pesticides. Et-mt dnnurf qe In <lrmMuo ct les nroprietes des PCBs sont scmblablcs A colics des pesticide* organochlores, ils ont tendance A fausscr la determination exactc des substances organochlorecs et orgnnophosphorecs lors d'anulysos par chromatographic en phase ga/euse via capture delectrons. En plus dc leur interference lors do I'anolysc des rfaidus des pesticides, fes PCBs sont cuxincmes des composes toxiques dont la determination quantitative est souhaitablc. Le present article conticnt urn* melhode qui permet de rcconnnitrc la presence des PCBs dans des cchantjJIons ct, en mime temps, de les separor des pesticides dont le taux dc residus pent Itm cxactcment determine. La methode permet cgalcment unc estimation du contenu total en PCBs. Des rlsultnts d'nnalyses portnnt sur des oiscaux aquatiques cana* diem jndiq'unt qu'un taux clove de PCBs est lie A un taux elcv6 de r&idus dc pesticides du groupe DDT. D'autre part, des taux eleves de nfsidus de substances organochlorecs nc sont pas necessnircment accompngnes d'un taux clove dc PCBs. Des reclicrchcs supplemcntaircs sur la toxicitc ct les effets subUtaux des melanges de PCBs et de leurs composes mdividucls seront ndcssnires. Si on peut d^montrer que des substances particulicres sont plus toxiques que d'autros, on aura besoin d une methode plus spccifiquc pcrmcltant l'analyse individuellc des PCBs. * Traduit par H. CcissoCiafn. MQNS 064132 84 X* M. Rstkoum Zusr.irmenfassung* Die Analyse von rflanzemihulzmittel*Ruckjtiinden in Gcgenwnrt von Polyuhlordiphcnylcn Sclt 1966 wcrden Polychlordiphcnyle (PCB-Stoffe) in Fischcn und Wildtieren, bcsondcrs in Europa und Nord.imcrika, nachgewiwen. Dio Vcrschmutzung dcr Wnss :nvr*ge durch Industric/ibfalle scheint dftbci dio JIauptursnchc von PCH-Riickstanclcn in dcr nquatischen Fauna zu scin. Die PCB-Slo fe wcrden fiir ciue Anzahl wichtizer Indusfricprozcssc gcbraucht, a* i Schudlingsbekampfungsmittcl werden tie jcdoch nicht eingesctzt. Da die PCB-Stolfc in ihrer Struktur und in ibren Eigcnschaften den chlorierten kohlcnwassc stoff-Insektizidcn schr ahnlich sind, kftnnen sic die gaschromatogr tphisclie Bcstimmung mit Elektronen* einCang-Detcktor von chlomr cn KohlcnwnsscTStoffcn und mancher Phosphorsiiorecstcr vorfjibchfi. Die PCB-S*offc konnen nicht nur RUclitaniUanalyscn beointrnc! tigen, sondem sic sind sclbst toxische Subst.inzcn, derrn Nnrhwcis aicli aufdrSngt. 1m vorlivgcndcn Artikel \sird cine Method*.* beschricbcn, die esc crlaubt, das Vorhandrnscin vo i PCB-Stoffcn in Probcn nachzuwcism, sio von den Schadling$bcka.npfnngsinittcln abzutrennen und die llilckstnndc drr Ictztcm genau zu bestienmen. Darubcr hinaus gwtattet die Miibode, den To algchalt an PCB-Stoffen abzuschhtzen. 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