Document JJ3Qb6d5O2Y4b2q4gBgKEpXBv

nbon Iclrichloiidc195 (1969). Hilnimd bodies of >66). lum, ind lead. Ann. lulioii of DDT by benzene In Japanese idtidion, and tissue d |rosa development t 1,1974 LABORATORY MODEL ECOSYSTEM STUDIES OF THE DEGRADATION AND FATE OF RADIOLABELED TRI-, TETRA-, AND PENTACHLOROBIPHENYL COMPARED WITH DDE RODEKT L. METCALF. JAMES R. SANUORN, PO-YUNG LU end DONALD NYU Department of Entomology and Environmental Studies Institute, University of Illinois and Illinois Natural History Survey, Urbana-Chanipotgn Urbona, Illinois 61801 Radiolabeled tri-, tetra-, and pcntachlorobiphenyls (PCB) and DDE were studied in a laboratory model ecosystem for degradation pathways, and biomagnification In alga, snail, mosquito, and fish. Tnchlorobiphenyl was degraded in ail the organismr. of the model ecosystem much more rapidly than tetrachloro- and pentachlorobiphcnyl. Pcntachlorobjphenyl was approximately as persistent as DDL. 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 TCB was detected. The laboratory model ecosystem previously described (Metcalf et al. 1971) has been employed for the estimation of the environmental fate of DDT and a number of its analogues (Kapoor et al. 1970, 1972, 1973) and for study of aldrin, dieldrin, endrin, mlrex, lindane, and hexachlorobenzene (Metcalf et al. 1973a). The methodology de veloped has yielded useful information about (1) the degradation pathways of the various xcnobiotics, (2) the toxic effects of the compounds and their degradation products, (3) their comparative biomagnificatjon and food chain concentration, and (4) their comparative biodegradabiMty; 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 et al. 1973b). In'this paper we report the application of these techniques to a better understanding of the comparative environmental properties of trichloro-, tetrachloro-, and pcntachlorobiphcnyl (I'ClTs), and of dichtorodiphenyldichlorocthylcne (DDE) the persistent DDT degradation product. Methods and materials The laboratory model ecosystem evaluation was carried out in a small glass aquarium with a sloping lerrestrial-aqu3tic interface of pure white sand exactly as previously de scribed (Metcalf et al. 1971). The t4C radio-labeled compounds were applied quantita tively from acetone solution at S.O mg (or ca. one kg per ha) to Sorghum vulgarc seedlings grown in the terrestrial portion. The treated leaves were consumed by fourtii instar salt Aivhivci EnvinNunrnut Cornkminatim ant Twkolojy, Voi. ). No. 2. IV7J O 1975 by Sponger-Verijg New Ymk Inc. 131 MONS 086473 152 R. L. Mcicalf a al. marsh caterpillar larvae Estigtnene acrea, whose activities and fecal products contaminated the aquatic portion of the system. The radiolabeled products were transferred through several food chains, c.g., alga (Oedogonium cardiacum) -* snail {Physa)\ plankton water flea (Daphnia mogiia) -* mosquito (Culex pipiem quinqucfanciatus) -* fish (Cambusia affinis). After 33 days in an enviionntcntal chamber at 26C and a 12-hr photoperiod at 5,000 foot candles simulated daylight, the organisms were extracted with acetonitrile and the ,4C-radiulabcled com* pounds evaluated by TLC on silica gel containing fiuoicsccnl marker (E. Merck GF-254) and radioautography on no*scrcen x-ray film. Liquid scintillation counting of the Individual components was done in cocktail D (5 g I'PO 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 ,4C02 by Ihe Schonigcr oxygen flask technique (Kelly ct al. 1961) to determine the unextractable radioactivity. Whenever possible, the identity of individual components on the TLC plates was determined by cochromatography with known standards and by extraction and mass spectrometry. Radiolabeled compounds. The individual 14C-labeled PCB's were obtained from Mallinkrodt.St. Louis, Missouri. They were: 2,5,2'-trichlorobiphcnyl (2,5-dichlorophenyliing-ULr,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,-letrachlorobiphenyi (ring-Uls14C), 9.87 mCi per mmole with > 98% radiopurity and 48.7% Cl, and a principal constituent of Aroefor 1248 (Webb and McCall 1972); and 2,4,5,2',5'-pcntachlorobiphenyl (2\5'-dichlocophcnyl*ring*UL-i4C), 9.87 mCi per mmole with > 98% radio* purity and 54.4% Cl, a principal constituent of Aroclor 1254 (Webb and McCall 1972). |4C labeled 2,2-Ms*(p*chloiophenyl)*l,I*dichloroethylene (DDE) was prepared from i4C-ffng*UL p.p'-DDT obtained from the Radiochemical Centre, Amersham, England, $.48 mCi per mmole, by dehydiochlorinating with 1.0 M alcoholic KOI!, and purifying on a silicic acid column with hexane elution to 99% radiopurity. Results ' PCB's. The movement of 14C radioactivity from Sorghum plants into the water phase of the model ecosystem is shown in Figure 1. All three chlorinated biphenyls reached a maximum concentration in water at about seven days after treatment and the levels of contamination declined as the PCB's were taken up by the organisms of the system. The levels of the chlorinated biphenyls in the water phase (Table I) were in the ppb range, below the water solubility of the compounds as determined by radiotracer technique (Table 11). Radioautographs of the extracts from the components of the model system after TLC ate shown In Figure 2. The data in Table I represent the quantitative distribution of the iC in Che spots on the TLC plates. The results for the three PCB's are also expressed in MQNS 036474 Ldttcts contaminated otf chains, e.g., alga (Dephnia magno) * f. Aflei 33 days in an oC ctndlcs simulated `Ottdlolabclcd com* `l (E. Merck CF-254) M counting of the phlhatcne in dioxanc melt talio quenching tmbuition to *C03 rtminc the unextrtetcomponents on the standards end by were obtained from l(2,5-dichloiophcnylS%Q,and a principal >*>tetrach)orobiphcny] TOG.and a principal $*2',S''pentachIorobi > with > 98% radio* band McCall 1972). L) vat prepared from Amttthim, England, : KOH, end purifying Degradation of Polychlorinated Diphenyls Compared with DDE 153 Tabic 11 in terms of ecological magnification (E.M.)'(ppm in org.inisin/ppm in water) and of biodcgrndability 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 tctuchloiobiphcnyl (48.7% Cl) to pcniachlorobiphcnyl (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 arc ecologically significant (see Kapoor ct ai. 1973) and must be a function of the number of C*H bonds available for hydroxyhilton by microsomal oxida tions in the various organisms. The spots of low Rf value (0.02-0.06), Figure 2, ace presumably hydroxyfalcd PCD compounds and.the polar radioactivity (Rf 0.0) is thought to consist of conjugates of these compounds. Wullnofcr etal. (1973) have found 4-chloto4'-hydroxybiplicny! as a metabolite of 4-cldorobiphcny! from soil fungus, Rhiiopus japonicus. Yoshimura and Yammamoto (1973) have reported the 5-hydroxylulcd deriva tive as the major and the 3-hydroxy)atcd derivative as the minor excretion product of 2,4,3\4'tetrach!orobiphcnyl in the tat, Uutzingcr ai. (1977) have shown that rat and pigeon could hydroxylate 2,5,2\5'-totrachlorobphcnyl but they could not detect hydroxylated metabolites in brook trout. However, the amounts of polar materia) in Cambusut (Figure 2, Table !) suggest that this fish is able to slowly hydroxylatc tltis tetrachlorobiphenyl. is Into the water phase 4 biphenyls reached a nenl uid the lewd* of norihetytlem.The me I* the ppb iaii|je, ndiottacci technique todel ylem fl*r TLC live Attribution of the .taietlioenptesKdin Fig. 1. Movement of total ,4C radioactivity from plants into the water phase of the model ecosystem end uptake by organisms. MGNS 086475 Table I. Distribution of chlorinated biphenyls and their degradation products in the-model ecosystem HjO Chlotinatcd biphenyl equivalents (ppm) Ocdogonium (ls) l'hysa (snail) Culex Cambusia (mosquito) (fish) I. 2,5,2*-lrichlorobiphenyl total 14C Unknown 1 (Rf 0.66*) Uichlotobiphenyl (Rf 0.56) Unknown 11 (Rf 0.23) Unknown III (Kr 0.10) Unknown IV (Rf 0.06) Unknown V (Rt 0.04) Unknown VI (Rr 0.03) Polar (Rf 0.0) UnextracUble 0.03845 0.00015 0.00020 0.00005 0.00055 0.00040 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 1.280Q 0.1595 -- --. -- -- 0.9985 0.5590 II. 2,5,2',5'-telrachloro biphenyl total14C tetrachlorobiphenyi (Rf0.48) Unknown 1 (Rf 0.23) Unknown 11 (Rf 0.04) Polar (Rf 0.0) Unextractable 0.02065 0.00120 0.00005 0.00155 0.01225 0.00560 23.6845 21.5975 0.3220 0.1030 0.3275 1.3345 53.7465 47.3275 0.7560 0.4360 3.9850 1.2420 14.5335 12.6745 0.1070 - 0.9670 0.7850 15.5685 14.2360 0.0890 -- 0.8545 0.3900 HI. 2,5,2\4\5*-pcntachlorobiphenyl total >4C pentachloro- biphenyl (Rf 0.55*) Unknown 1 (Rr 0.46) Unknown II Unknown HI (Rf 0.21) Unknown IV (Rf 0.04) Unknown V (Rr 0.02) Polar (Rr 0.0) Unextractablc . 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 $.4330 TLC with hexane (Skcllysolve B,bp 60-68*C). 633.0165 181.4565 127.6945 587.3545 170.8480 8.6210 2.4070 2.2490 23195 1.9365 1.0520 03000 7.4965 163530 83040 -- 2.6745 3.1555 119.7060 2.5380 0.5810 0.3285 0.7450 2.3610 1.4350 154 MOWS 086476 V TWt n. Ecological magnification (EM.) and Blodegradeblllty index (B.l.) ofKB's and DDE compared with water solubility and partition coefficient H30 solubility Partition Chemical a ' (PPb) coefficient Ecological magnification (E.M.) Alga Snail Mosquito Fish tri-Cl-PCB ' 16 7,803 7,315 5,795 815 6,400 tetra-CI-PCB 16 8,126 17,997 39,439 10,562 11,863 penta-Cl*PCB 19 16,037 5,464 59,629 17,345 12,152 DDE 1.3 18,893 11,251 36,342 59,390 12,037 Biodegradability index (B.l.) Alga Snail Mosquito Fish 0.30 0.17 0.35 0.60 0.015 0.082 0.076 0.060 0.029 0.027 0.0134 0.019 0.069 0.049 0.033 0.050 MQNS 0 3 6 4 7 7 i ...... ...i 156 R. L. Metcalf ci ol. The pcntachloiohiphcnyl with D.I. values of 0.019 to 0.027 in fish and snail is very comparable in model ecosystem behavior to DDT, D.I. 0.015 and 0.044 (Kapoor ct at. 1973) and this suggests that the two compounds should behave similarly in the environ ment (Risebrough ct at. 196$). Properties of the tctrachlorobiphcnyl were similar to (hose of the pcntachlorobiphcnyl (Figure 2) but ihc (richlorobiphcnyl w-js much more degradable. A prominent degradative product (Rf 0.66) is stored in alga, snail, and mosquito larva in much greater quantities than the parent compound. This compound is Jess polar (higher R() in the hexane solvent than any of the three PCB isomers. As shown Jn Table I it is magnified to very high values, I06.382X in alga and 126.4S0X in snail, is stored in lipids, and is highly persistent. Its presence in high amounts in alga and in the snail and mosquito which are alga feeders suggests that it might be 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 iricliiorobiphcnyl by alga, snail, daphnia, mosquito or fish (Metcalf and Lu 1973) although it appeared in alga in Fig. 2A. Radioautogram of TLC plate con* taining extracts of water and organisms treated with 2,$,2,.*trchlorobiplicnyl. A (alga), F (fish), M (mosquito larva), S (snail) and STD (,4C**adiolabeled com* pound). Fig. 2D. Radioautogram of TLC plate con* taining extracts of water and organisms treated with 2.5,2\5'-tetrachlorobiphenyl. A (alga), F (fish), M (mosquito larva), S (snail) and STD (t4C-radioiabe)ed com* pound). HONS 086478 Ith and mail is very 1.044 (Kipoor ct at. flirly } Ihr. environtnyf were similar to yl wit much more : in alga, snail, and id. This compound is >8 isomers. As shown 126,4flOX in snail, is its In alga and in (tie be formed by photo* nd forms slowly and wobiphenyi by alpa, It appeared in alga in Degradation of Polychlorinated Diphenyls Compared with DDE J57 M-day studies. To data we have been unsuccessful in identifying the unknown by mass spectrometry. DDE. This compound has been implicated as a possible environmental precursor of PCD isomers through photoxidation reactions involving radical rearrangements to 3,6-dichlorofluorcnonc intermediates (Plimmer ct at. 1970. Pcakall and Lincer 1970, Moilanen and Crosby 1973). Although such rearrangements could logically produce, 4,4'-dichlorobiphcnyl, it is difficult to see how trichloro- and tctrachiorobiphcnyls could be formed as suggested by Maugli (1973). Moreover, Kerner ct at. (1972) could detect only hrj-(/>'chloiophcnyl)-chlofoethy!cne (DDMU) after ultraviolet irradiation of DDE. Because of the ecological importance of these possible rearrangements we have reinvesti gated the behavior of DDE in the model ecosystem (Metcalf ct at. 1971) to determine if any PCB likc products could be formed under the simulated daylight of the mode] ecosystem (5000 foot candles) in an environmental chamber. The radioautograph show- ogram of TLC plate con- ef water and organisms I`.j'-tetrachlorobiphenyl. \ M (mosquito larva). $ (<C-radiolibtIed com- Fig. 2C. Radioautogram of TLCplate con taining extracts of water and organisms treated with 2,4,5,2',5'-pentachlorobi* phenyl. A (alga), F (fish), M (mosquito larva), S (snail) and STD (> ^-radiolabeled compound). Fig. 2D. Radioautogram of TLC plate con taining extracts of water and organisms heated with DDE. A (alga), F (fish), M (mosquito larva), S (snail) and STD 0 4C-radioIabcled compound). MONS 086479 1*58 K. Li Metcalf cl al. Ing flic fate of pure DDE is presented in Figure 2. When the extracts of water and organisms were developed on TLC plates with Skcllysolvc B (hexane fraction) there was no trace of any 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, tetrachlnrnbiphcnyl Rf 0.50, and pcntachlorobiphenyl Rf 0.53. Detection levels with the techniques used arc approximately 0.1 ng (e.., spot at alga origin in DDE, Figure 2) or about 0,000027o of the total `4C applied. Tims under the model ecosystem conditions there is no evidence of formation of.l'CB isomers from DDE. DDE is extremely stable in the tissues of the living organisms of the model ecosystem and is stored as approximately 92, 93, 95, and 97% of the total ,4C in snail, alga, fish, and mosquito larva. The percent of uncxtractable HC in these organisms ranged from 0.10 to 0.93 (Table III). Hie D.I. 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 al 86 to 94% of the lota! radioactivity, with from 1.12 to 8.67% of unextraclable >4C, and had a B.l. of 0.019 and an E.M. ofl2,152 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 dilorine content were degraded when trans ported through the food chain, as was 2,.`>,2'-triciilorobipiienyl in uu, experiments. Hew ever, in our studies (Figure 2, Table HI) the water phase contained several polar radio- Table III. Distribution of DDE atuJ degradation products ' in the model ecosystem H,0 DDE equivalents (ppm) Oedogortium Physa (.!) (snail) Culex (mosquito) Gambu.ua <fih) Total 'C 0.00384 DDE (Rr 0.49*) 0.00062 Unknown 1 (Rf 0.05) 0.00009 Polar (Rr 0.0) 0.00223 Unextraclable 1 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). HONS 006480 ilets of wile' n<1 liaclloit) llicic was nd 0.47 (DDK) oi lillons, s shown in ,ind pcnlachloioblptoxlmalcly 0.1 ng it total1 *C applied. ,r (oimat ion of I'CB the model ecosystem C in snail, alga, fish, lanterns ranged from f and the E.M. value .(1971). Fiom l''csf riant than 2,4,5,2 ,5 * at t6 to 94* of the C, and had a B.l. of Degradation of Polychlorinated Biphenyls Computed with DDE 159 labeled degradation products. These were resolved on silica gel into at least 11 distinct compounds usings solvent of bcn/.cnc:dioxanc:accticacid (90:30:1) and we arc presently attempting to identify the pathway of DDF. degradation in the cnviionmcnt. Biomass Recovery. To determine the relative availability of the various organisms of the model ecosystem as reservoirs for the bioaccumulation of (he micropollutants studied, the total amounts of i.4C-labclcd products recovered front the principal organisms of the model ecosystems treated with tri-, totra*, and pentachloro-PCB's, and DDE were evaluated as shown in Table IV. The evaluations were made on the basis of total re covery of the applied pollutant, recovery of the maximum amount of pollutant in water (Figure J) 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 I). The figures of Table IV are very tevealing in terms of (he biodegradability of the various compounds. The highest recoveries of the >4C lost from solution were ob tained from the organisms with DDF, 65.8%, and pcntachlorobfphcnyl, 57.27a With tetrachJorobiphcnyl recoveries of 8.7% were still substantial, but with tricldorobiphcnyl (recovery 0.45%) the compound was nearly completely degraded and excreted. ecosystem found no foot chain Into ft*, mixture (Clophcn A) degraded when trsnsw experiments. Howted several polar radio- induct* p> _ Ctln (motouito) Cimbusia (fish) 24.151! J6J223 7.8653 7.4632 | 1.244! 0.10*1 0.3746 0.0275 Table IV. Biomass recovery of chlorinated biphenyls, and DDE from organisms of model ecosystem % Recovery Alga Snail Mosquito Fish triehlorobiphenyl ,4Cin solution 0.18 0.015 total t-C .0.033 0.0028 * (biomass) of ,4C lost from solution--- 0.45 0.0017 0.00032 tetrachlorobiphenyl t*C in solution 3.33 1.04 0.23 total I4C 0.28 0.088 0.019 (biomass) of 14C lost from solution --- 8.7 pen taehlorobiphenyl *4C in solution ' 4.57 19.0 2.32 (pill I4C 0.74 3.06 0.37 (biomass) of ,4C lost from solution ---57.2 ,4C in solution ' 22.4 4.03 total l *C . 0.24 0.044 (biomass) of *4C 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 nk. MONS 066481 ...... J 160 R. l-- Metcalf rt a!. Degradation in Salt Marsh Caterpillar. This animal was chosen, after considerable Study,-as the dispersing agent for the model ecosystem because it was able 1o ingest a large variety of organic compounds without appaicnt injury (Metcalf ct al. 1973). The effects of passage of the PCB isomers through the insect arc of interest as representing the fust 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 *rg of >4C PCD incorporated in a synthetic diet. Figure 3 and the quantitative trl-CI tetra-CI pcnta-Cl Fig. 3. Radioautogram of TLC plate containing extracts of bodies and feces of salt marsh caterpillar larvae fed 4C*labcled 2,3,2'-ui-, 2,5,2',5'-tctra-, and 2,4,5,2',5'-peniachlorobiphenyls. B (body homogenate), and F (fecal excreta). MGNS 08648^ i, after considerable able to incest a llfeffl/. 1973). The rest as representing we 3 shows radio l from larvae feeding and the quantitative fro r 4les and feces of tall marsh od 2,4,S.2\5*pentachloro- Degradation of Polychlorinated Biphenyls Compared with DDE 161 evaluation of the radioactivity in the various spots shown in Table V demonstrate con clusively the much greater degradability of (lie Irichlorobiphcny! over the tcirachlorobiphenyl and pcninehlorobiphcnyl. With the trichloro compound the caterpillar feces con tained 91% of the recovered 14C, with the remainder in the body homogenate, while with the tctracldoro- and pcntachlorobiphcnyls, the feces contained 21% and 24% of the radioactivity. The unknown (Rf 0.05) found in feces after trichlorobiphcnyl is probably the principal hydroxylated degradation product leading to the very large amount of polar radioactivity. Whereas.only low levels of trichlorobiphcnyl were retained in the salt marsh calcrpillar body, with tetrachloro- and pcmachiorobiphcnyl the major portion of 14C was retained in the insect body. Table V. Metabolism of14C radiolabeled compounds by salt marsh caterpillar Body Feces A. 2,3,2'-trichlorobiphcnyl total ,4C(%) Unknown 1 (Rf 0.53*) trichlorobipheny! (Rr 0.43) Unknown 11 (R, 0.31) Unknown 111 (Rf 0.13) Unknown IV (R, 0.0S) Unknown V (Rr 0.02) Polar (Rr 0.0) B. 2,5,2,,S,-tetrachIorobiphenyl total ,4C(%) letrachlorobiphenyl (Rf 0.50*) Unknown l(Rr 0.41) ' Unknown 11 (Rf 0.05) . Unknown 111 (Rr 0.03) Folir (R, 0.0) C. 2p5,2',4,^,-pentachIorobiphenyI total 14C(%) pentachlorobiphenyl (Rf 0.53*) _ Unknown I (Rf 0.46) Unknown 11 (Rf 0.39) Unknown 111 (Rf 0.03) Polar (Rr 0.0) D. 2,2-6/r-(p-chlorophenyl)-l,l-dich!oioethylene (DDE) total >4C(%) * DDE (R, 0.49*) Polar (Rf 0.0) TLC with hexane (Skcllysolvc B, bp 60-68*C). 8.66 0.64 S.84 0.27 0.05 0.10 0.11 1.6$ 78.68 75.60 0.99 0.13 trace 1.96 75.86 74.00 0.74 0.62 0.08 0.42 80.59 76.88 3.71 91.34 - 8.91 0J7 0.12 4.67 0.92 76.35 21.32 15.08 1.36 0.20 4.64 24.14 20.70 0.74 0.56 0.08 2.06 19.41 19.37 0.04 HONS 066463 . ... / 162 R. L. Metcalf ci at. DDE: passed through \hc sail maish caterpillar largely unchanged with 81% of the total radioactivity recovered retained in (he body homogenate and 19% in the fecal excreta (Table V)- Ecological Magnification. The uptake and concentration of organic compounds by living organisms cither .directly or through food chains appears to be a function of (wo important factors, their high lipid solubility and low water solubility, i.c., a large lipid/ water partition coefficient; and their resistance to degradation by'enzymatic processes, especially the multifunction oxidase enzymes (Metcalf cr at. 1973). Uamclink ct 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 the PCB's and DDE from the fish of the model ecosystems with both water solubility (Table 11) in Figure 4, and with the octanul/watcr partition value (Table II) in Figure $. Because the values for the )*CB's and DDE fall closely together, the relationships have been extended using values for aniline, anisole, benzoic acid, chlorobenzene, and nitrobenzene taken from oilier model ecosystem studies (Lu and Metcalf 1974). For the limited number of compounds included, the correlation between physical properties and biotmgnificalion is excellent. Tire regression equation for log water solubility vs log E.M. (Figure 4) was: y*4.4806 - 0.4732X : n~9, r*-0.9677 HONS 066484 >ed with 81% of the nd 19% lit the fecal i i i ' gtnic compounds by be a function of two ity, /.c,, a large lipid/ eitf.yniatic pioccsrcs, 73). Utmclin): ct at. table compounds pro )f simple partitionings 11*1 and DUE from the > in Figure 4. and witli st the values for the extended using values rne taken from other lumber of compounds ntflcation is excellent. t)was: 77 Degradation of l'olychUuiiwivd Biphenyls Compared with DDU 163 The regression equation for log partition coefficient (llansch's n) vs. log 1;.M. (Figure 5) was* ' ' y ** - 0.7504 + 1.1587 X : n9, r* 0.9771 Thus for the organic compounds studied, the properties of water solubility and octtmol/waler partition coefficient appear to provide a realistic estimate of the biological magnification found in living organisms. I---------1--------------1 Lo 7.0 IX itareolubllity (ppb). Fig. S. Plot of log E.M. (ecological magnification) for fish vs. log octanol/water partition coefficient. . Acknowledgments This research was supported in part by. research grants from the U. S. Department of Interior, Office of Water Resources Research through the University of Illinois Water Resources Center Project B-050, Illinois; tire National Science Foundation Crant Gl 39843X, the U. S. Environmental Protection Agency Grant R802022 and Grant R800736, and the Bureau of Veterinary Medicine, Food and Drug Administration, Contract FDA7M16. t. HONS 086485 A 'S. 164 R. L*. Mcttaif.fi ol. References Costs. J. R., R. L. Metcalf, and I. P. Kapoor: Metabolism of the mcthoxychlor isosicrc, dianisylncopcnlane in mouse, insects, and a model ecosystem. Pesticide Uiochcm. Physiol. 4, 201 (1974). Datts, P. R.: In vivo detoxication of p,//-DDT via p./Z-DDC top.p'-DDA in rats. Ind. Med. 39,190(1970). Hamclink, J. L., R. C. Waybrant, and R. C. Ball: A proposal: exchange equilibria conuol the degree chlorinated hydrocarbons arc biologically magnified in lemic environ ments. Trans. Am. Fisheries Soc. 100, 207 (1971). Huizinga, O., D. M. Nash, S. Safe, A. S. W. DeFreitas, R. J. 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