Document ym72oXMnMKOmEp2JERgMzg14

carbon lelnchlorldc,495 (1969). n bitlm ind bodies of (1966). Imlum, end leed. Ann. Ulbillon of DDT by fobenttne In Japanese induction, and tissue in4 (ton development |'J). 20,1974 5 5 T97n LABORATORY MODEL ECOSYSTEM STUDIES OF THE DEGRADATION AND FATE OF RADIOLABELED TRI-, TETRA-, AND PENTACHLOROBIPHENYL COMPARED WITH DDE ' ROBERT L. METCALF, JAMES R. SANBORN. PO-YUNC LU end DONALD NYE Department of Entomology and Environmental Studies institute. University of Illinois and Illinois Natural History Survey, l/rbana-Champatgn Urbans, Illinois 6 i 801 t 1 1 . Radiolabeled tri-, tetra-, and pcntachlorobiphenyls (PCS) and DDE were studied in a laboratory model ecosystem for degradation pathways, and hiomagnification in algo, snail, mosquito, and fish. Trichlorobiphenyl was degraded in all the organ isms of the model ecosystem much more rapidly than tetrachloro- and pentachlorobiphenyl. Pcntachlorobiphenyl was approximately as persistent as DOE. There was a linear relationship between lipid/water partition and ecological magni fication and between water solubility and ecological magnification. No evidence of conversion of DDE to PCB was detected. The laboratory model ecosystem oceviousiv described (Metcall ef al. 19711 has been employed for the estimation of the environmental fate of DDT and a number of Us analogues (Kapoor ct al. 1970, 1972, 1973) and for study of aldrin, dicldrin, endrtn, mirex, lindane, and hexachloiobenzcne (Metcalf el al. 1973a). The methodology de veloped has yielded useful information about (1) the degradation pathways of the various xenobiotics, (2) the toxic effects of the compounds and their degradation products, (3) their comparative biomagnifiention and food chain concentration, and (4) their comparative biodegtadabiKly; all in organisms of five phyla linked in several food chains. This information has proved of value in characterizing the potential environ mental pollutant effects of candidate insecticides (Kapoor etal. 1973,Coats etal. 1973) and of plasticizers (Metcalf ef al. 1973b). In this paper we report the application of these techniques to a belter understanding of the comparative environmental properties of ttlchloio-, tetrachloro-, and pcutachlorohiphcnyl (1`CH's), and of dichlorodtphcriyidichioiocthylcnc (DDE) the persistent DDT degradation product. Methods nnd materials The laboratory mode) ecosystem evaluation was carried out in a small glass aquarium with a sloping terrestrial-aquatic interface of pure white sand exactly as previously de scribed (Metcalf cl al. 1971). The >4C radio-labeled compounds were applied quantita tively from acetone solution at 5.0 mg (or ca. one kg pur ha) to Sorghum vulgar* seedlings grown in the terrestrial portion. The treated leaves were consumed by fourth instar salt Aicbtott ef Eavwwmmal ComMmntfiw and Texitetorr. Vo. 3- No. 2. IV73 C IV7S by Spnnfcr-Verlit New Ywk Ine. 151 MQNS 093274 152 R. L. Metcalf tt at. marshcatCTpilhrhrvaeEsligmcncacrea, whose activities and fecal products contaminated the aquatic portion of the system. The radiolabeled products were transferred through several food chains, e.g., alga (Oodogonium cardiacum) - snail (Physa)\ plankton -* water flea (Daphnia magna) -* mosquito (Culex pipiens quinqucfasciatus) - fish (Gambusia affinis). After 33 days in an environmental chamber at 26C and a 12 hr photoperiod at 5,000 foot candles simulated daylight, the organisms were extracted with acetonitrile and the 4C-iadiolabcled com pounds evaluated by TLC on silica gel containing fluorescent marker (G. Merck GF-254) and radioautography on no-screen x-ray film. Liquid scintillation counting of the individual components was done in cocktail D (5 g PPO and 100 g naphthalene in dioxanc to make one liter) and counts were corrected to dpm by using channels ratio quenching correction. The residues, after extraction, were counted by total combustion to l4COj by the Schbniger oxygen flask technique (Kelly er at. 1961) to determine the unextractable radioactivity. Whenever possible, the identity of individual components on the TLC plates was determined by cochromatogiaphy with known standards and by extraction and mass spectrometry. Radiolabeled compounds. The individual l4C-IabeIed PCB's were obtained from Mallinkrodt.St. Louis, Missouri. They were: 2,5,2'-trichiorobiphenyl (2,5-dichlorophenyl* ring-UL-,4C), 9.91 mCi per mmole with >98% radiopurity and 41.5% Cl, and a principal constituent of Aroclor 1242 (Webb and McCall 1972); 2,5,2',5' tctrachlorobiphenyl (ring-UL-14C), 9.87 mCi per mmole with > 98% radiopurity and 48.7% Cl, and a principal constituent of Aroclor 1248 (Webb and McCall 1972); and 2,4,5,2',5'-pcntachlorobipheny! (2\5,-dich,`rtro',h**nyi-rm.llM4CV 9.87 mCi per mmole with > 98Vb raaiopurity and 54.4% Cl, a principal constituent of Aroclor 1254 (Webb and McCall 1972). - <4C labeled 2,2-bfs-{p-chlorophenyl)-l ,l*dichlorocthylcne (DDE) was prepared from ,4C-ring-UL p,p'-DDT obtained from the Radiochemical Centre, Amersham, England, 5.48 mCi per mmole, by dehydrochlorinating with 1.0 M alcoholic KOH, and purifying on a silicic acid column with hexane elution to 99% radiopurity. Results PCB's. The movement of ,4C radioactivity from Sorghum plants into the water phase of the model ecosystem la shown in Flguic 1. All thiec chlorinated biphenyls icailicd a maximum concentration in water at about seven days after treatment and tire levels of contamination declined as the PCB's were taken up by the organisms of the system. I he levels of the chlorinated biphenyls in the water phase (Table I) were in the pph mnp.c, below the water solubility of the compounds as determined by radiotracer technique (Tabic II). Radioautographs of the extracts from the components of the model system after TLC are shown in Figure 2. The data in Table 1 represent the quantitative distribution or tire t4C in Ihe spots on tire TLC plates. The results for the three PCB's are also expressed in M0NS 093275 product! contaminated Jbod chatna, e.g., alga {Daphnla magna) * fter33dayt tn an foot candles simulated MC-ridlolabeied com' kit (E. Merck GP-254) lion counting of the saphlhalenc in dioxane annels ratio quenching combustion to |4C0} Hrnnlne the unextracti components on the wn standards and by l were obtained from yl (2,5`dichlorophcny)- 1.5% Ct, and a principal ''-telrachlorobiphony( 1.7% Cl, and a principal * v+' r-~............... Me with > uuiu' ibb and McCall 1972). BE) was prepared from a Amenham, England, lie KOH, and purifying Degradation of Polychlorinated Diphenyls Compared with DDE 153 Tabic II in terms of ecological magnification (E.M.) (ppm in organism/ppm in water) and of biodegradability index (B.l.) (ppm polar degradation products/ppm nonpolar products). The E.M. values for the parent compounds increased substantially with the number of chlorine atoms, from trichlorobiphcnyl (41.5% Cl) to tctrachJorobiphcnyi (48.7% Cl) to pentaclilorobiphcnyl (54.4% Cl). Conversely the B.I. values decreased with increasing degree of chlorine. This consistent and regular behavior gives added confidence that these parameters are ecologically significant (sec Kapoor et al. 1973) and must be a function of (he number of C-H bonds available for hydroxylation by microsomal oxida tions in the various organisms. The spots of low Rf value (0.02-0.06), Figure 2, arc presumably hydroxylated PCB compounds and the polar radioactivity (R< 0.0) is thought to consist of conjugates of these compounds. Wallnofer el al. (1973) have found 4-chloro4'-hydroxybiphcnyl as a metabolite of 4-chlorobiphcnyl from soil fungus, Rhizopus japonicus. Yoshimura and Yammamoto (1973) have reported the 5-hydroxylatcd deriva tive os the major and the 3-hydroxylated derivative as the minor excretion product of 2,4,3',4'-tetrachiorobiphcnyl in the rat. Hutzingcr el al. (1972) have shown that rat and pigeon could hydroxylatc 2,5,2'.S'-tetrachlorobiphenyl but they could not detect hydroxylated metabolites in brook trout. However, the amounts of polar material in Gambusia (Figure 2, Table 1) suggest that this fish is able to slowly hydroxylate this tetiachlorobiphenyl. mil Into Ilia water phase del biphenyls readied a Mmcnt and the levels of uliiiisof the system. The \ were In the ppb unge, y radiotracer technique ! \ * ; j arodel system after TLC gative distribution of the CVs are also expressed in ! j Fig. 1. Movement of total )4C radioactivity from plants into the water phase of the model ecosystem and uptake by organisms. r MONS 093^76 / M ' '"'w Table 1. Distribution of chlorinated biphenyls and their degradation products in the mode! ecosystem HjO Chlorinated biphenyl equivalents (ppm) Ocdogonium (alga) Physa (snail) Culex Camhusia (mosquito) (fish) I. 2,5,2,-trichlorobiphenyl total 4C Unknown 1 (Rf 0.66) tiichiorobiphenyl (Rr 0.56) Unknown 11 (Rf 0.23)' Unknown HI (Rf 0.10) Unknown IV (Rf 0.06) Unknown V (Rf 0.04) Unknown VI (Rf 0.03) Polar (R, 0.0) Unextractable 0.03845 0.00015 0.00020 0.00005 _ 0.00055 O.OQ040 0.00040 0.02265 0.01405 23.2155 15.9575 1.4630 0.0520 __ _ _ 0.0685 0.5185 5.1560 31.2015 18.9720 1.1590 0.6480 0.9735 0.5460 0.2205 0.4410 3.9315 4.3100 2.7030 1.1995 0.1630 + _ _ _ 0.4795 0.8610 3.2055 0.2085 1.2800 0.1595 _ ,, _ -- 0.9985 0.5590 11. 2,5,2\5'*tetrachloro biphenyl total |4C 'hlorobiphcnyl (R; 0.48*) Unknown I (Rf 0.23) Unknown 11 (Rt 0.04) Polar (Rr 0.0) Unextractable 0.02065 nnntft) 0.00005 0.00155 0.01225 0.00560 23.6845 53.7465 21.5975 At.sin 0.3220 0.7560 0.1030 0.3275 1.3345 0.4360 3.9850 ' 1.2420 14.5335 12.674 3 0.1070 _ 0.9670 0.7850 15.5685 ;.......... 0.0890 _ 0.8545 0.3900 III. 2,5>2r,4',5'pcnta- chlorobiphenyl total |4C pentachloro- biplicnyl (Rf 0.55) Unknown I (Kf 0.46) Unknown II (Kr 0.39) Unknown III (Rf 0.21) Unknown (V (Rf 0.04) . Unknown V (Rf 0.02) Polar (Rf 0.0) Unextractable 0.04340 0.00985 _ 0.00020 0.00015 0.00030 0.00385 0.02055 0.00850 62.4660 53.8440 0.6850 0.5080 0.1425 _ 0.2570 1.6265 $.4330 TLC with hexane (Skellyaolvc B,bp 60-68#C). 633.0165 181.4565 127.6945 587.3545 8.6210 2.2490 1.9365 0.5000 7.4965 16.5550 8.3040 170.8480 2.4070 1.3195 1.0520 _ 2.6745 3.1555 119.7060 2.5380 0.5810 0.3285 _ 0.7450 2.3610 1.4350 154 MUNS 093*77 t i I W-- W ooe oo WM I tOOO VAV** \ P Os e o p o o sVO Oo Ol a 9 sr e ! 4 5 C z tr iable II. Ecological magrdficatior. {EM.} and Biodegradability index (B.I.} o/PCB's and DDE compared with wtter solubility and partition coefficient H}0 solubility Chemical (PPb) tri-Cl-PCB 16 tetra-Cl-PCB 16 pcnta-Cl-PCB 19 DDE 1-3 Partition coefficient ____Ecological magnification (E.M.) Alga Snail Mosquito Fish 7,803 7,315 5,795 815 6,400 8,176 17,997 39,439 10,562 11,863 16,037 5,464 59,629 17,345 12,152 18.893 ll.JSl 36,342 59,390 12,037 Biodegradability index (B.I.) Alga Snail Mosquito Fish 0.30 0.17 0.35 0.60 0.015 *0.082 0.076 0.060 0.029 0.027 0.0134 0.019 0.069 0.049 0.033 0.050 093278 156 R. L. Metcalf ct at. The pentachlorobiphenyl with B.!. values of 0.019 to 0.027 in fish and snail is very comparable in model ecosystem behavior to DDT, 0.1. 0.015 and 0.044 (Kapoor ct at. 1973) and this suggests that the two compounds should behave similarly in the environ* men! (Riscbrotigli ct at. 1968). Properties of the tctrachlorobipheny! were similar to those of the pcntachlorobiphcnyl (Figure 2) but the trichlorobiphcnyl was much more degradable. A prominent degradative product (R( 0.66) is stored in alga, snail, and mosquito larva in much greater quantities than (he parent compound. This compound is less polar (higher Rf) in the hexane solvent than any of the three PCB isomers. As shown In Table I it is magnified to very high values, 106.382X in nlga and 126.480X in snail, is stored In lipids, and is highly persistent. Its presence in high amounts in alga and in the snail and mosquito which arc alga feeders suggests that it might he formed by photo chemical processes during photosynthesis in the alga. This compound forms slowly and no traces of it were visible In three-day uptake studies of triclUorobiphenyl by alga, snail, daphnia, mosquito or fish (Metcalf and Lu 1973) although it appeared in alga in hyl. Fig. 2A. Radioautogram of TLC plate con taining extracts of water and organisms treated with 2,5,2'*trichlorobipheny]. A (alga), l? (fish), M (mosquito larva), S (snail) and STD ('4C-radiolabclcd com pound). hyd. Fig. 2B. Riulioautogram of TLC (dale con taining extracts of water and organisms treated with 2,5,2',5'-tclrachlorohiplu-nyt. A (alga), F (fish), M (mosquito larva), 5 (snail) and STD (14C-radiolabclcd com pound). MGNS 093279 Ath Mid snail Is very 0.044 (Kapoor ftal. .nUirfy in the environ* henyl were similar to henyl was much more ed in alga, mail, and and. This compound is *CB isomers. As shown id IM,480X In snail, is ants in alga ami in the I he formed by photo* aind forms slowly and hlofobiphcny! by alga, 3II appeared In alga in ' ' . ` ( j j ; ! 1 1 ; j I 1 Degradation of Polychlorinated Biphenyls Compared with DDE 137 14-day studies. To data we have been unsuccessful in identifying the unknown by mass spectrometry. DDE. Tills compound has been implicated as a possible environmental precursor of PCB isomers through photoxidation reactions involving radical rearrangements to 3,6-dichiorofluorcnone intermediates (Plimmer et al. 1970, Tcakall and Lincer 1970, Moilanen and Crosby 1973). Although such rearrangements could logically produce, 4,4'*dichlorobiphcnyl, it is difficult to see how trichloro* and tetrachlorobiphcnyls could be formed as suggested by Maugh (1973). Moreover, Kcrncr et al. (1972) could detect only i*/S'(p-chlorophcuyl)-chlotocthylcne (DDMU) after ultraviolet irradiation of DDE. Because of the ecological importance of these possible rearrangements wc have reinvesti gated the behavior of DDE in the model ecosystem (Metcalf ctal. 1971) to determine if any PCB-like products could be formed under the simulated daylight of the model ecosystem (5000 foot candles) in an environmental chamber. The radioautograph show* Cl *1* Cl Cl ci Cl Cl Cl Cl liyd. HOftrini ml Tl.CpInte con , of water and organisms ,J.$'-llchloiobl|>lwnyl. h), M (moiqulto lrv). S 0 (i*C-c*4tolbled com- hyd. Fig. 2C. RadioaiHogNim of TLCpIalc con* tlining extracts of water and organisms treated with 2,4,5,2\5,-pcntachlorobiphenyl. A (alga), F (fish), M (mosquito larva), S (snail) and STD 0 ^'-radiolabeled compound). Fit!. 2D. Kntlinnutogrum of Tl.CpIale con taining extracts of water and otr.auisms treated with DDE. A (alga), !: (lish), M (mosquito luiva), S (snail) and STD (,4C-radiolabcled compound). HUNS G932QQ ----- M 'X*. 158 R. L. Metcalf rf al. ing the fate of pure DDE is presented in Figure 2. When the extracts of water and organisms were developed on TLC plates with Skciiysotvc B (hexane fraction) there was no trace of any 1 4C labeled compounds with Rf values between 0.05 and 0.47 (DDE) or of any less polar materials with higher Rf values. Under these conditions, as shown In Figure 2, trichlorobiphcnyl has Rf 0.43, tctrachlorobiphcnyi Rf 0.50, and pentachlorobiphenyl Rf 0.53. Detection levels with the techniques used are approximately 0.1 ng (e.g., spot at alga origin in DDE, Figure 2) or about 0.00002% of the total 14C applied. Thus under the model ecosystem conditions thcic is no evidence of formation of PCD isomers from DDE. DDE is extremely stable in the tissues of the living organisms of the model ecosystem and Is stored ss approximately 92, 93, 95, and 97% of the total l4C in snail, alga, fish, and mosquito larva. The percent of unextractable 14C in these organisms ranged from 0.10 to 0.93 (Table III). The B.l. value for DDE in fish was 0.049 and the E.M. value 12,037 (compared with 0.032 and 27,358 found by Metcalf et al. (1971). From these values it is apparent that DDE is a more stable environmental pollutant than 2,4,5,2',5'* pentachlorobiphcnyl (Table I) which was stored in the organisms at 86 to 94% of the total radioactivity, with from 1.12 to 8.67% of unextractable l4C, and had a B.l. of 0.019 and an E.M. of 12,152 in fish. It Is of interest that Sodergren (1973) using a model aquatic ecosystem found no major metabolic changes in DDE occurring in passage through a food chain into fish, although similar experiments with a polychlorinated biphenyl mixture (Clophcn A) showed that the lower fractions with low chlorine content were degraded when trans ported through the food chain, as was 2,5,2 -triclilorobipiienyl in uui experiments. How- eve:, Jr. cu; atuiicc (Figure 2, T?b!* t'*) *** phase contained several oolar radio- Table HI. Distribution of DDE and degradation products in the model ecosystem HjO DDE equivalent* (ppm) Oedogonium 1`hysa () (snail) Culex (mosquito) Gambusia (fish) Tot|iC 0.00384 DM! (Rf 0.49*) 0.00062 Unknown I (Rf 0.0S) 0.00009 Polar (R( 0.0) 0.00223 Unextractable 0.0009 7.4720 6.9759 0.4881 0.0080 38.1958 22.5325 0.8035 1.1612 0.3616 24.8588 36.8223 1.2448 0.1087 7.8653 7.4632 0.3746 0.0275 TLC with hexane (Skellysolve B, bp 60-68*C). ( | ( t t t< (i MONS 093231 Xtndi of witer tnd ic fraction) there was )S and 0.47 (DDK) or nditlons. as shown in O.and pentachlorobiipproximaicly 0.1 ng the total' 4C applied, of formation of PCB f the model ecosystem i*C In snail, alga, fish, organisms ranged from 49 and the E.M. value 01.(1971). Prom those Qutant than 2,4,5,2 ,5 nt at 86 to 94% of the iC, and had a B.l. of ic ecosystem found no food chain into fish, | mixture (Clophen A) i< dtgraded when tians* 5 our experiments. How* in+A rvera) polar radio* rntoct* ClrfM Gatnhusia (mnqnliit) (11.10 24.XSM 36.1223 7.1653 7.4632 1.2441 0.1017 0.3746 0.0275 Degradation of Polychlorinated Biphenyls Compared with DDE 159 labeled degradation products. These were resolved on silica gel into at least 11 distinct compounds using a solvent of bcnzenc:dioxac:acetic acid (90:30:1) and we arc presently attempting to identify the pathway of DDE degradation in the environment. Biomass Recovery. To determine the relative availability of the various organisms of the model ecosystem as reservoirs for the bioaccumulation of the miciopolluiants studied, the total amounts of 14C-labelcd products recovered from the principal organisms of the model ecosystems treated with tri*, tetra*, and pentachloro-PCB's, and DDE were evaluated as shown in Table IV. The evaluations were made on the basis of total re* covcry of the applied pollutant, recovery of the maximum amount of pollutant in water (Figure 1) for each of the four principal organisms, alga, snail, mosquito, and fish; and biomass recovery (four organisms) of the total amount of pollutant lost from water (Figure 1). The figures of Table IV are very revealing in terms of the biodcgradability of the various compounds. The highest recoveries of the ,4C lost from solution were ob tained from the organisms with DDE, 65.8%, and pentachlorobiphonyl, 57.2% With tetrachlorobiphcnyl recoveries of 8.7% were still substantial, but with triclilorobiphcnyi (recovery 0.45%) the compound was nearly completely degraded and excreted. Table IV. Biomass recovery of chlorinated biphenyls, and DDE from organisms of model ecosystem ' % Recovery Alga Snail Mosquito Fish tnvhiurobiphenyi lCin solution 0.18 0.0 IS total 'C P.033 0.0028 (biomass) of HC lost from solution ---- 0.45 0.0017 0.00032 ` tetrachlorobiphtnyl *4C In solution 3.33 1.04 0.23 total MC 0.28 0.088 0.019 (biomass) of l4C lost from solution -- - 8.7 pentachlombiphcnyl 4C in solution 4.57 19.0 2.32 total <C 0.74 3.06 0.37 (biomass) of 14C lost from solution -- -57.2 * 4C in solution 22.4 4.03 total 1<C . 0.24 0.044 (biomass) of4c lost from solution -- -65.8 DDE 2.25 0.055 0.12 0.021 1.91 0.16 11.8 1.90 20.2 0.22 MONS 093282 160 R. L. Metcalf ct al. Degradation in Sait Marsh Caterpillar. This animal was chosen, after considerable study, as the dispersing agent for the model ecosystem because it was able to ingest a large variety of organic compounds without apparent injury (Metcalf et al. 1973). The effects of passage of the PCB isomers through the insect are of interest as representing the first stage in the biodegradation of these compounds. Figure 3 shows radio autographs of TLC plates of extracts of feces and body homogenates from larvae feeding on about 30 /ig of 14C PCB incorporated in a synthetic diet. Figure 3 and the quantitative tvl-CI tetra-CI penta-CI Fig. 3. Radioautogram of TLC plate containing extracts of bodies and feces of salt marsh caterpillar larvae fed ,4C-labcied 2,5,2f-tri-, 2,5,2\5,*tetca*, and 2,4,5,2\5,-penlachlorobtphenyls. B (body homogenate), and F (fecal excreta). MQNi> 093283 4, after considerable t was able to ingest a calf etal- 1973). The uemt is representing Igutt 3 shows radiotes from larvae feeding 3 and (he quantitative itfCi 1 i c. F MtiM and facet of nit marah ad 2,4,5,2\5''Pcntachloro- Degradation of Polychlorinated Diphenyls Compared with DDE 161 evaluation of the radioactivity in the various spots shown in Table V demonstrate con clusively the much greater degradability of the triclilorobiphcnyl over the tctrachiorobi* phenyl and pcntachlorobiphcnvl. With the trichloro-compound the caterpillar feces con tained 91% of the recovered l4C, with the remainder in the body homogenate, while with the tetrachJoro- and pentachJorobipbenyls, the feces contained 21% and 24% of the radioactivity. The unknown (Rf 0.05) found in feces after triclilorobiphcnyl is probably the principal hydroxyiated degradation product leading to the very large amount of polar radioactivity. Whereas only low levels of trichlorobiphenyi were retained In the salt marsh caterpillar body, with tctrachloro- and penlachlorobiphenyl the major portion of 4C was retained in the insect body. Table V. Metabolism of !4C radiolabeled compounds by salt marsh caterpillar Body Fecea A. 2,5,2f-trichlorobiphenyl total 14C(%) Unknown I (Rf 0.53*) trichlorobiphenyi (Rf 0.43) Unknown!! (Rf 0.31) Unknown HI (Rf0.13) Unknown IV (R/ 0.05) Unknown V(Rf 0.02) Polar (Rr 0.0) B. 2,6,2 ,5 -tetracmorooipuciiyi tui 'C (X) tetrachlorobiphenyl (Rf 0.50*) Unknown I (Rf 0.41) Unknown 11 (Rr 0.05) . Unknown HI (Rf 0.03) Polar (Rf 0.0) C. 2,5,2*,4',5'-pcntachlorobiphenyl total l4C(%) pentachlorobiphenyl (Rf 0.53*) Unknown I (Rf 0.46) Unknown 11 (Rr 0.39) Unknown III (Rf 0.03) Polar (It, 0.0) D. 2,2-Mr-(/-ch)orophcnylM,l-dichiorocthytunc (DUIi) total ,4C(%) DDli(R, 0.49*) , Polar (Rf 0.0) TLC with hexane (Skellysolve B, bp 60-68*0. 8.66 0.64 5.84 0.27 0.05 ' 0.10 0.11 1.65 78.68 75.60 0.99 0.13 trace 1.96 75.86 74.00 0.74 0.62 0.08 0.62 80.59 76.88 3.71 91.34 8.91 0.37 0.12 4.67 0.92 76.35 71 37. 13.UO 1.36 0.20 4.64 24.14 20.70 0,74 0.56 0.08 2.06 19.41 19.37 0.04 MOMS 093^04 162 R. L. Metcalf tt at. DDE passed through the salt marsh caterpillar largely unchanged with 81% of the total radioactivity recovered retained in die body homogenate and 19% in the fecal excreta (Table V). Ecological Magnification. The uptake and concentration of organic compounds by living organisms either directly or through food chains appears to be a function of two important factors, their high lipid solubility and low water solubility, i.c., a large lipid/ water partition coefficient; and (heir resistance to degradation by enzymatic processes, especially the multifunction oxidase enzymes (Metcalf tt at. 1973). Hatneiink et at. (1971) have suggested that the water Insolubility of highly lipid-soluble compounds pro vides the driving force in producing lipid storage, through a series of simple partitionings from water to lipids. We have correlated the E.M. values for die PCD's and DDE from the fish of the model ecosystems with both wrict solubility (Table U) in Figure 4, and with the octanol/water partition value (Table U) in Figure 5. Because the values for the PCB's and DDE fad closely together, the relationships have been extended using values for aniline, anisolc, benzoic acid, chlorobenzene, and nitrobenzene taken from other model ecosystem studies (Lu and Metcalf 1974). For die limited number of compounds Included, the correlation between physical properties and biomagnification is excellent. The regression equation for log water solubility vs log E.M. (Figure 4) was: y - 4.4806 - 0.4732 X : n * 9, r * - 0.9677 Fig. 4. Plot of log E.M. (ecological magnification) for fish vs. log water solubility (ppb). Q932B5 MONS T anged with 81% of the i end 19% in the focal organic compounds by to be i function of two bOiiy, a largo lipid/ by ensymitic processes, 1973). Kamcllnk et at. soluble compounds pro* oof simple partitioning *CB's and DDE from tiie II) in Figure 4, and with use the values for the n extended using values tune taken from other I number of compounds tgnifkatlon is excellent. e4)was: 1677 1 Degradation of Polychlorinated Biphenyls Compared with DDE 163 Tire regression equation for log partition coefficient (Hansch's rr) vs. log E.M. (Figure S) was: ' y *-0.7504+ 1.1587 X : n*9, r*0.9771 Thus for the organic compounds studied, the properties of water solubility and octanol/watcr partition coefficient appear to provide a realistic estimate of the biological magnification found in living organisms. * nlllna * ___ i 10 7.0 i 0.0 'eater solubility (ppb). Fig. S. Plot of log E.M. (ecological magnification) for fish vs. log octanol/wulcr partition coefficient. . Acknowledgments This research was supported in part by research grants from the l). S. Department of Interior, Office of Water Resources Research through (he University of Illinois Water Resources Center Project B-050, Illinois; the National Science Foundation Grant Gl 39843X,.thc U. S. Environmental Protection Agency Grant R802022 and Grant R800736, and the Bureau of Veterinary Medicine, Food and Drug Administration, Contract FDA 72-116. MONS 093286 164 R. L. Metcalf et a!. References Costs, J. R., R. L. Metcalf, and I. P. Kapoor: Metabolism of tho mcthoxychlor Isostere, dianisylncopcntanc in mouse, insects, and a model ecosystem. Pesticide Biochcm. Physiol. 4, 201 (1974). Datta, P. R.: In vivo detoxication of p.p'DDT via p,p-DDE to p.p'-DDA in rats. Ind. Med. 39,190(1970). ^ Hamelink, J. L., R. C. Waybrant, and R. C. Ball: A proposal: exchange equilibria control the degree cJiloiinatcd hydrocarbons are biologically magnified in lentic environ ments. Trans. Am. fisheries Soc. 100, 207 (1971). Hutzlngcr, O., D. M. Nash, S. Safe, A. S. \V. DcPrcitas, R. J. Norstrom, D. 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