Document DdX6Yb2J4xoYBM0Rmb3zp8DvM

Artiv;it:*ll !' :r?1;irN* Ly L 1 l l l K LII. \ U. I C.": ^ S \ l ' i H 3 n u U. v II I I 1111 J. 5 ,1/mijot" ( l`ii S t I nm mui v. * / ** ti 1(<00 M a r c h -o. I ' / ' a Since the i d e n t i f i c a t i o n of p o l y c h l o r i n a t e d biphenyl (PCd) r e s i d u e s in the e n v i r o n m e n t in S w e d e n ( J e n s e n . 1966) an e f f o r t has b e e n m a d e lu d e t e r m i n e the level and d i s t r i b u t i o n of there m a t e r i a l s as well as their effects upon living organisms. The widespread di str i b u t i o n of low but d e t e c t a b l e levols of some PC3s in the e n v i r o n m e n t is n ow well d o c u m e n t e d and a s u b s * a n t i a l amount of data have been a c c u m u l a t e d r e g a r d i n g their acute, subacute, and chronic toxicity (Pea kail and Lincer, 1970; Edwards, 1970). V/hile m u c h is k n own a b o u t the e f f e c t s of PC3s on living organisms, there is r e l a t i v e l y l i t t l e in f o r m a tion available regarding the effects that living oi gun isms have upon PCSs, i.e. t h eir b i o d e e j r a d a b i l it y . The b i o d e q r a d a b i l i t y or susceptibility of an organic c o m p o u n d to b i o l o g i c a l d e g r a d a t i o n , e s p e c i a l l y by b a c t e r i a , is a p r ime d e t e r m i n a n t of its e n v i r o n m e n t a l r e s i d e n c e t m : . The f i n d i n g of PC3 r e s i d u e s in tne e n v i r o n m e n t s u g g e s t s to m a n y thot PCBs as a c l ass of c o m p o u n d s ore r e s i s t a n t to m ic ro l>io 1 d e g r a d a t i o n . H o w e v e r , in o - d e r to f a i r l y e v a l u a t e the p e r s i s t e n c e of rcr.s it m u s t fcv u n d e 'stood that l'C2s are pot a s i n g l e entity, but complex m i x t u m s made up of many entities which may u n d e r g o b i o logical d e g r a d a t i o n at d i f f e r e n t rates. Ch l o r i n a t e c b i p h e n y l s are c o m m e r c i a l l y p r o d u c e d by the direct c h l o r i n a t i o n of biphenyl. The resul t a n t m i x tures can t h o r e t i c a 1 ly have as m a n y as 10 d i f f e r e n t c o m p o n e n t s c o n t a i n i n g 0-10 c h l o r i n e atoms per hi phenyl molecule. Of the possible isomers, 1C 3 are consid e r e d r c r t p r o b u u l ? (W i time, r!c , 196?). The c o m p l e x i t y of the PC.is, t h e - c fere, c o m p l i c a t e s the d e t e r m i n a t i o n of both en-, iron m e n t a l levels and their impact on the biota. E n v i r o n m e n t a l m o n i t o r i n g p ro g ra m s have d -1o n ->tr te d that, with the exception of direct high 1e v r 1 c o n t r o l l able c o n t a m i n a t i o n n e a r p o i n t s of ir.jnu fa c tu re or use, nYiili..iI.I,..Ni,rIo ir'lbr b|iM>crfVI|( VV.1--T ..V>.ifr l l.l.*ccf.. 70S r /* ACM C & Lht' PCI'.*. (| ii1 1y fp h ncl in lho cnv i..... .u l are the more highly t h 1nr ii*e led biphenyl"., i.e., those cor. 1n iu ing S or no re chlorine itc^s per hi phenyl m o l n ; u 1c (Jensen end I.1i(li.idr I , 190/; llolncs, c t n 1 , 19G7: Kerman, e t a 1 , 196 9). Tin's is tree even though the no re highly clil ori na ted biphenyls co n s l i t n i e only about 3 6T. *nf o 11 the I'Cfis nanu- fac lured over' the years (M o n ? an Io Company, 1971). This is strnnrj e v i d en ce that the less c h l o r i n a t e d mate ri al s dec; redo more rapidly than the more highly c h 1or inr ted ones. It also suggests that even under co n d i t i o n s of u n r e s t r i c t e d use and w i t h ou t special pr nc ao ti on s to prevent entry into the environment that the less chlor- in : tc d a ie ia 1s degraded rapidly enough to p rc*ven t a cc u-.j 1a tiot:. It is olivine*. , there fere, that to oh ta*in a more complvt' unde is tar.d p.g of the env iron;;if* n Lal h r h a v ; c r of I'Ctls t.n*il ip for-'a t ion c o nc er ni ng their s u s c e p t i b i l i t y to i.iicrohisil d e g r a d a t i o n is needed. It iics been shewn that biplienyl can be deg ratio cl by gre---.'native teeter ia through 2, 3 -dihydro -2 , 3 - d i h y d rc ;.yb ipI.e ny 1. -hy d ro xy -p- p heny 1r.toc o n ie s c*mi -a 1de hyde and pi;c :-y 1 p y r u va te {Lunt. ind Evans, 1970 ), and it h =s be i:11 repeated that P seu cnr. qji_? s^ p u_l_i da ox id iz es b i; n ;r.y 1 th ro j gr ?. ,3 -d ihy d r0 - 2,3 -d iiiyd roTy biphenyl and i cnro ic acid (Ca t e 1ani , e t a 1, 1971). More re cently Gib:-or z r.C c o -,.:o:*i-e is isol a Led a bectori o n , t e *` \ ' v :1y id t t i : icd as a Dc ijc-r in c!J a species from a pel I'.`Led strr; *., ca pable of ut i 1 iz'i"n !iphenyl as a so'e source of r - T o r and energy for yrrwLh (Cibron, et <:1 . 1973/ t.*;' cr eanisms capable of ox id i z i n g b ir " *.y 1 irid y -: u 1c rn biphc*nyl h;ive been shown to be wide ly d is l .*lbe t^c in the natural env ircnnenl (Ohmori, e t si. 1973). U e ..:-*da t ien studies have also been ca rried out on soiv.e s e l e ct ed PC isomers with two specie' of Ac hrcr.o hac le r isolated fmi: go (Ahmed and TochL. lC73a,h) and i:i th A roc Io r 1c 'i? (Ka is c r a nd i.'ontj, 19 /.i) . To date, no r!. h ;.z been reported on the b ioueg ;v.e L ion of c o ; r c ia 1 PCn m I/.tu res by ac tivated sludge. In the study reported liere, the sn.se ('pi -lily of C0r-r*c r c i 11 p o 1y c h 1o r i n jl ed biphenyl i.,o t i c c> to p r i mary deg rt.(!,* t ion by ac tivated sludyi u ie ioorga n isms was investig-lied. 70i. r i . i ii_n;iS a ?:b t a 1r i , v j Pt) 1ycl ; 1u r i >:a t e d Di p h e n y l M i x t u r e s I h c f o l l o w i n g |o 1yel l 1o r i rid l e d b i p h e n y l mi >l u r e s r s n u f ' t t u i u d by Men'- a n i o Company v; er c s t u d i e d : A r o c l o r 1 1?:>7 , A r o c l o r 127 2 , A r o c l o r 1016, JiCS 1072 ( n o t a coi ::ncrc i e 1 i.ii x t lm R) , and A r o c l o r 122 I . In T 11c I , tn*? t y p i c a l p e r c e n t c o m p o s i t i o n o f t h e n i x t i r c r s t u d i e d is given in terms o f the number of c h l o r i n e atoms per b i p h e n y l . TA':i >; 1 1 YP ! C. AL t:Cif : 5 i TI O: : Of P C L Y L0j_ L )> ; _i Pj; i i ..c r ? ' i Cl in - phony i G 1 2 3 7 5 6 7 8 A r r,c 1o r 1221 ( ?i c i ) ( 11 bl 32 7 2 <0.5 f! 0 >\ V :;d lies 107 3 ci ) 0.1 22 72 G i; D wo wo wo WD Aroclor 1016 ( 7i:. ci ) <0.1 1 20 57 21 1 <0.1 WO wu Aro cl or 1272 lA A'i:_C.11 <0 .1 1 16 79 25 8 1 <0 . 1 WD Arucloi* 1237 Cl) <0.1 <0.1 < 0.5 1 21 7a 23 G i:*j * Vor cer.: factors. ',j` GC/ ;a s s t; s i n g a i*e e c o r r e c t i o n i;;j - 1:o . o V 4.1 . 01 v. Qi gd : t. r ; Cs, *. i o n Ii ? tl:Od 7h ? p r if*: c r y d e y r a Ca l i n n r a t c o f t he PCC r.i *>: t u r r c '..as de t e n . . i ne *.i u s i n c t h e Sc ap s nd D e t e r g e n t Ass y c 1f. c i o n S e r i - c on t i n o u s t'C t i Vt" t ad s 1u ci g e ( SC/.S) p r e c odi ; r r* end r o d i f i c:ti f e e d ( S . D . A . 19GG , 19-39) . Th e* r. l e d ' c n n i t used r as ii ey 1i 11(I i "i ca 1 g 1ij s s chrimlic r (05 i\r 0 of H.on i: 1 ;;oi *!:i nt| VLr 1Ul.it; wi 11. p r o v i s i u m f o r ?. 2 r.; -. : on , mti tjn< t . c s * i r r i u r , s amp 1i i k: iiiid ri re i r. i n g . T>i : r: t i - v .1i c c! s l u d g e c u l t u i e was oh l C. i n e d f ro:.i r. l o c a l * :: n i C - pal Si.*want- t re;1, t'lio n t p i a n t linci a c c i i Ced on s y r t h . e i . i c sewage ( 300 mg o f g l u c o s e ^ ? 00 my n u t r i e n t h r n t h f 130 my K ll 7 1* U .. rp i! 1i t e r } f o r s e v e r e 1 w u o 'r.s p r i o r t o t h s t a r t o f a c t u a l f r od i ii ij o f t he p o l y c h l o r i n a t e d h i p ' i v n y mi x. t u r e s . The m i x e d l i q u o r ( s l u d g e + aqueous p i . us e) 1P.egis Lered tradenarh of Monsanto Company 70? ACM CC 5^9 S vi.ts initially adjusted in each sludge unit to a s u s pended solids concentration of about 2500 mg/liter and during the course of the tests readjusted to this value on a weekly basis. Each cycle was initiated by the addition of synthetic sewage and the PCB being studied. Because of their low water solubility, the PCB mixtures being tested were fed via syringe injection of 200 ul of an ethanol solution. In this manner, homogeneous dispersions of the PCGs on the bacterial sludge were obta ined. After about 30 minutes of aeration, a 20 ml aliquot of the nixed liquor was withdrawn and analyzed for the PCB mixture in question. Aeration was continued until the end of the cycle when a second 20 ml sample of mixed liquor was withdrawn for analysis. At this point, the aeration was stopped and the sludge allowed to settle. After noting the sludge volume, two-thirds (1000 ml) of the supernatant was withdrawn and replaced with tap v/ater. Monitoring of the sludge volume and supernatant pM provided some indication of satisfactory operation of the unit. The units were generally operated on two 4S-hour and one 72-hour cycle per week. Analytical Methods The PCBs in the mixed liquor samples were isolated from the sample matrix by solvent extraction using either nanograde or sosetroqrade hexane. After concentrating in a Kutierna-Cani sh evaporative concentra t o r , the e x tracts were analyzed for PCBs by either electron-capture gas chronatography (EC/6C) or ultraviolet {UV ) spectro photometry. The UV analyses were made with a Cary Model 14 recording spectrophotome ter and matched 2.0 cm quartz cells. The gas chromatographic analyses were carried out with a Hewlett-Packard 57 50 chromatograph equipped witJi a H i 51 el ec tran -ca p tu rs detector. A 2 m x 4 mm glass c o l umn packed with 4* XE-60 on GO / 1GO mesh Chromosorb W, H.P., was employed. The temperatures of the injection port, column and detector were 220"C , 170-220C, and 300C, respectively. Calibration curves were prepared using standard solutions of the appropriate PCB mixture. In Tahle II, the wavelength of the absorption maxima and absorptivities employed in the UV analyses are given. Aroclor 1254 did not have sufficient UV absorp tion for analytical purposes. 70B AC f* CC 5 5 w.w TALE It ULTRAVIOLET ABSORPTION: up RECOVERY D A T \ FOR B I P H E N Y L A N if P O L Y C H L O ' N A T tl) ill P H t h Y L M I R T U R c.3 Material A M.a x . , n m Ab sorpti v ity Li t e r s / g - c m Per Cent Recovery B ip h e n y 1 A r o c l o r 1221 MCS 1043 Aroclor 1016 A r o c 1or 124 2 Aroclor 1254 * 246 245 244 246 245 - 110.9 66.4 48.9 36.1 37.0 - 9 3 - 3 96 + 1 95 + 1 92 + 1 04 + 1 76 * 2 *Ana iyze by EC/C In order to demonstrate the efficiency of the e x t r a c tion procedure, samples activated sludge wore spiked in duplicate at two levels, 2.5 and 5 ppm, with each of the materials end then carried through the entire analytical procedure. The recovery data for each PCD fluid studied are given in Table II. No isomer d i s tribution changes were observed upon comparison of the eleci r o n -capture chromatograms of the PCB reference materials to those of the spiked sludge extracts. In order to show that the PC3swere not irreversibly ad sorbed on and/cr stored within the bacterial cells of the activated sludge and therefore not recovered via extraction, a sample of acclimated Aroclor 1016 nixed liquor was homogenized with a Polytron Sonic Uomogenizer to lyse the bacterial cells and then extracted. A 10G ml sample of homogenized mixed liquor gave a PCB level of 0.51 mg compared to 0.53 mg for an identical mixed liquor sample treated in the normal manner. RESULTS AMD DISCUSSION ]n Figure 1, the per cent degradation rates and 95Z confidence limits obtained in this study are given for biphenyl and the PCB fluids. It is apparent from the plot of degradation rate vs weight per cent chlorine that the level of chlorination of the m i x ture is the most significant factor in the relative degradability of the PCBs. The.degradation rates reported here were obtained after the sludge units had been acclimated for abnut 5 months to the appropriate PCD. * Initially the PCD mixtures were fed at a rate of 1 mg per 24-hour cycle, but b e cause of the relatively slow rate of degradation observed in spot checks, the cycle time was increased to 48 hours. \ 709 ADM CC55CI 1254 Figure 1. SCAS primary biodegradation rates of commercial PCBs as a function of the weight per cent c h 1ori ne . Since Aroclor 1221 was found to be quite degradahle, the effects of both tir.= cycle and feed level war? studied briefly. In Table III disappearance rate data obtained for 24 and AS-hour tine cycles at 1 and 5 mg feed levels are given. It is apparent that for Aroclor 1221, most of the degradation occurs during the first 24 hours. This car he explained by the fact that the lower chlor inated biphenyls degrade more rapidly than the higher chlorinated biphenyls. > To verify that the disappearance of the PCGs was due predominantly to degradation and not to volatilization, off-gases from the Aroclor 1221, MCS 1043, end Aroclor 1015 units were passed through ,i train of th*-ce hexane scrubbers during several comp] e-1-"' cycles. At the 0.1 cubic foot per hour aeration rare, the disappearance rates due to volatility were 4.2, 6.1, and 3.0- for Aroclor 1221, MCS 104j, and Arcciur 1016, ro:pec t ivfi1y . These losses are well within the 95 confidence limits of the overall disap p,earance rates. \ 710 TAGLE M l EFFECT OF TIME C'VCLc A*\`IJ TEE'J LEVEL UN THE ARdCLOH 122 1 D [SAfVL'Alin.'iLC NAT Feed Level Disappearance Pa ta , T24 -iTr LycU- o3 -H r Cycle 1 mg 5 mg 73+21 89+17 81+6 87+5 In order to observe changes in the distribution of the chlorinated biphenyls in the PCBs mixtures after exposure to the activated sludge, selected samples of Aroclor 1221, MCS 1043, Aroclor 1016 and Arcelor 1242 viere analyzed by EC/GC. The chromatogram fer Aroclor 1221 is shown in Figure 2. The top trace is a c h r o matogram of the Aroclor 1221 standard, representative of the feed m a t e r i a l . The center trace is. tnat of a concentrated sludge extract taken at the end of a degradation cycle. At the bottom is a trace of an Aroclor 1242 standard run under equivalent conditions. The numbers above each peak indicate the dominant PCD represented by the peak as determined by GC/Mass spectrometry. Comparison of the extract chromatograms to that of the Aroclor 1242 standard shows that the minor components in Aroclor 1221, which do not degrade as rapidly, are the major components in Aroclor 1242, it * MINUTES Figure 2. Typical electron capture chronia tog rams for Aroclor 1221, after exposure to activated sludge for 24 hours, and Aroclor 1242^. 711 AM C C o 5C 2 It is important to note that the electron-capture detec tor does not have the satr.e response for all components. With PCUs, the sensitivity of the detector generally increases as the degree of chlorination increases. From the Aroclor 1221 chromatograms, it is apparent that the dominant monoch 1orob ipheny 1 and d ich 1o rob ipheny 1 c o m p o nents are readily degraded. Once the major components of Aroclor 1221 are degraded, the minor more slowly degrading components are easily observed after concen tration of the sludge extracts. Similar, less dramatic, alterations were noted for KCS 10*33 and Aroclor 1242. ho differences were observed in the extract and Aroclor 1254 standard chromatograms. CONCLUSIONS The results of this study demonstrate that commercial PC3 mixtures which contain predominantly mono- and dic h 1o r o b i p h e n y 1s readily undergo primary biodegradation under the experimental conditions employed. The data also illustrates that as the levels of t r i - t tetra-, and p e n t a c h 1orobiphenyls increase, the degra dation rates decrease accordingly. This resistance of the more highly chlorinated biphenyls, particularly those containing 5 or more chlorine atoms per molecule, explains in part their detection as residues in weathered biological and environmental samples. \ 712 A DK CC55C<t ACKNOWLEDGEMENT We are grateful to J. P. Mi eu re for dete^niir.inn the typical composition of the PCB products studied. REFERENCES AHMED, M., and FOCHT, D.D., Bull. Environ. Contam. and T o x i c o l ., JO, 70 (1973a ). AHMED, II. , and FOCHT, D.D., Can. J. Microbiol. 1_9 , 47 ( 19 7 3 b ) . CAT EL Ifil, D., S0 RL 1N I , C.. and TRECEAIil , V . f Experientia, 2_7, 1174 ( 19 71). EDWARDS, R. , Chemistry and Industry, .20, 1340 (1970). EVANS, W.C. and LUNT, D., Diochem. J. 113, 54P (1970). GIBSON, O.T., R O BERTS, R.L., WELLS, M.C. and KOBAL, V.V., Biochem. Biophys. Res. Comm., 50, 211 (1973). HOUSES, D.C., SIMMONS, J.H., and TATTON, J.O'G., ' Nature, 2J_6, 1274 (1967 ) . JENSEN, S., and WIDMARK, G., "Unintended Residues in the Environnent", O.E.C.D. Report (1967). JENSEN, S., New Sci., 32, 612 (1966). KO EMAN , J.H., TEN NOE V !( UE BRAU, M .0 ., and DE VOS, R.H., Nature 22J_, 1126 (1965 ). Monsanto Company, C h e n . E n g . News 9, 15 (1971). OHMO.Hl, T. , IKA, T., MI NO DA, Y. and YAMADA, K . , Aqr. Biol. Chen. 7_, 1599 (1973). P E A K A L L , D.5., and LINCER, J.L., Bio Science, 20 , 958 (1970).' Soap and Detergent Association Sub-Committee on Biodegradation Test Methods, J. Aner. Oil Chem, Soc. 46, 432 (1969). Soap and Detergent Association Sub- Con:ni ttee on Biodegradation Test Methods, J. Amer. Oil Chem. Soc. A_2, 986 (1965). WIDMAP.:'., G., "Ds tern iria fion of the. Number of C o m pounds Which Can Result F r o m the Chlorination of Biphenyl and De vu 1oi>",-',-rit of a Simple System hy Uhich These May be Codified", O.E.C.D. Report, Sweden (1958). \ 713 ADM CC55C5