Document EdBKpYbQ1dRjvKLrg9gbZL294

oo (Rrpr</ front Nature, Vo/. 216, No. 5122, pp. 1274-1276, December 30, 1967) FRESHWATER FISHERIES REPRINT N9 119 Organochlorine Pesticides in Seals and Porpoises by A. V. HOLDEN tC MARSDEN Preihwstsr Plihsris* Laboratory, Pitlochry, Perthshire Seal* and porpoises In Scotland and Canada, far from the sites of application of pesticides, can accumulate high concentrations of residues In their blubber. These chemicals are spreading through the tong food chain which ends with seals and porpoises and obviously cannot be confined to their place of discharge. Tmm presence of orgunochlorino residues in marine life in many area* of tho world, including the Ant arctic, lmis boon reported recently'-*. In British notors tho accumulation oi residua mi the cgg of mu birds* nnd the process of oonoontrution of pesticides through certain food chains in the marine envinmimnu1 Imve been studied- Analyses of various species of marine fish nnd mammnls from Soottish water# during the past o year#3'* have shown ihal orgnnouhlorinc residues are now a normal ocour- reiioo, tho highest concentrations being found in organs or tissue* with die highest lipid content. Thus the muscle tissue of Bidinouidri. the livers of cod and kite blubber of goals act as storage sites for these residues. The aquntio mammals, such as whales, seals and por poises, have a relat ively high proportion of the body weight in the form nf subcutaneous fut- (blubber). Seals food ohiufly uu gadoids umlsalmouids, and porpoises chiefly on small gadoid* and ehipooids. The process of concentration of pesticides tiirougli their food chain might be expected to reeult in high i*c#ticidelevels in the fat ofthese mammals, and samples unaivsod at this laboratory confirm this expectation. In recent years, specimens of the grey seal {Haiichotntt grypu$). common seal (I'hocn eitulwo) and porpoise (Phocatnn j'ltoatetia) have been sampled from the coast# of Scot land. Samples of blubber were available for all tho spcoinuins examined, and in a few cases other Organs wore also available. Ax well as recognized pesticide rostducH, oilier electron-capturing substances have been detected bv gas-liquid ohroniatography and, in order to establish whether such substances ore as widely distributed as the pesticides, blubber samples from grey seals and harp seals {I'ltooa groenlamlica) on tho Canadian Atlantic count have also been examined and tho results or thoso analyses are reported Imre- Examination of samples of son) blubber front other areas is continuing in order tn assess tho variation between different regions tf th marine environment. All tissue samples from Scottish waters were frozen' at -18*0 until required for analysis. Tho Canadian sumples were preserved in 10 nor cent formalin, which showed no evidence of any inmiouce on the atmlyiical procedure, nnd In this and other cases involving ti.li it has not afl'cctod tho efficiency of recovery of pesticide residnos. Aliquots of the samples (G g) were ground to powder with anhydrous crystalline sodium sulphate (AH grade) and extracted in a Soxhlet apparatus with re distilled AR grade n-hexnno (previously tested and found to be free of clecirou*capturing materials by gas chromatographv). The hexnne extructs were made up to 100 ml. and -i> ml. aliquots were subjected to aiesn-up by the hoxnne-dtracthylfurmamidc partition louthod of d Faubcrt Maunder et a/.', followed by column clean-up using alumina containing 5 per cent water. The lorn of pesticide residues from fat extracts so treated is up to 20 per cSnt, but, as is customary in pcstici'du inmly*:*, no correction has been made for such losses' in the results prosonted here. The clcaned-up hcxunc extracts were snuiyMil b> guliqnid chromatography on a Vatinti `Aerograph 2U3-2&' instrument employing two glass columns .5 ft. long h | m outer diamoter. One oolumn was packed with `Chrumo. sorb IV A IVIDMCS 80-100* mesh coated wil h 10 pci cent HONS 081903 rr D /JG'*200 siiicono Oil, and tlic other with the Mine support coated with 9 per oant DC*200 + 7-9 per cent Oi'-l fluonjiilioone- The oven temperature was 200 C, the nitrogen gut flow 90 ml./min and the column resolution for dteldrm equivalent to 1,900 theoretical plates. There was no signiflonnt degradation of DDT on the columns. While oomploto separation of the common pesticide residues is possiblo on ono or other of these columns, interference by polychlorinated biphenyl (PCB) residues'1' with p,p'.TDK and p,p'-DDT peaks necessitated o further analytical stage. Aliqviots (9 ml.) of some of the extracts were evaporated to dryness in a stream of cold Alteted air, and the residues refluxed with 2 ml. of 2 9 per cent alooholic potassium hydroxide for 15 min on a warm water-bath. Alter cooling, 9 ml. of n-hexane was added, with mixing, followed by 40 ml. of 2 per cent sodium sulphate solution. The supernatant hexane layer was thim analysed by gas-liquid chromatography. By this teehninuo, quantitative conversion of p,p'-DDT to p,p'- DDK, atid of p.p'-TDK to p.p'-MDE (-DDMU), is ob- tainod, and the couvorsion products confirm tho identity of tho original revalues. The residual peeks in the p.p'*DDT and p,p'-TDE positions, where present, oan be subtracted from the values of tho postiuides originally determined in these positions. Hydrolysis also destroys and y-BHC, whpiti pitwent, but ptdyehlorhuited biphenyls aro uu* affocted. A cyaiiosiiioous (X/C-60) column1* lias also been ueod to soparate p.p'-DDT and p.p'-TDE from PCB inisrPi'itmiiv, confirming the tatter. Tlic principal pesticide residues found in all samples examined were those of the DDT group, with diddrin in much smaller quantities. Canadian seals contained lower oonnentrations of dioldrin than Scottish seals, whilo Scottish porpoises contained remarkably .high concentra tions of oil pvstieide residue* (see Tahlo 1). Interference on the DC-SOOsilicono column in t he p.p'-TDK position caused by a non-hydrolysahle residue was responsible for abottt 26 per cent of thd total estimated p,p'-TDB in the Canadian and Scottish samples examined. In the p,p'- DDT position, the nott-hydrolysable residue constituted about 10 per cent in the Canadian samples and about 30 por oent in the Soottish samples examined for this interferonrn, tlto total amount- of non-hydrolysable material boing smaller m the Canadian samples. The values in Table 1 have not been corrected for this inter- forenoe, for otdy a proportion of the samples were hydro* lyecd. Results from tho various species of seals were not noticeably different in a given rea, and have been combined in Table 1. * 1. COXerSTKAttOS RAXUR* Ol OHVANUCHLOHINI PIKIIOCrS IX FAT or tnmt 4.vn rourcuu (p.p.m.) <Mesnln rNurnUti^r*) typAe<ovTkaifmtdpM wNaon.ptnh DklJrtn K. Kfiitlana, adult IS (Ml-t i X. sail W. asetkiMl, sdultsfslstlMpM) X.MMdl W. SssitMxl. Csnsds, NASllMlA U.. |(u19v3.?*n) t Mlnll smU* CmB'Ia, Csltsi Sirslts. Jvaivi..tIimmm.isimt diIhII SrelUml. Orkney. adult {HtrpnlBPMSS*) X Seeilini). <ulit<) 1937) o-os-cse ((HOI 0-03-0-44 00(2O-0-I-S0I1 <0-031 to-ti-i (S3) 18-70 0-4) HMD (S-5) 0-97-1-S U-8) p.p-TDE 0*7-10 a-t> o-u-o-ss 0-1(03--401-)M (0-39) 0 03-010 (0)3) F.jt'-DDT 1-3-*$-$ (Jl). (9-0)' M-S-7 (3-3) oos-o-m (0-83) Contamination by pesticides is greater in the seals on the east const of Scotland (taken in an nren roughly from Aberdeen to the Tay estuary) than in epecimens from the west ami north coasts, including the Orkney Islands. Seal pups from the Orkney and Harris (west coast) breed* ing ground* contained only slightly lower residues than adults from the same arcus. Ry comparison, the Canadian samples from t he Magdalen Islands (Gulf of St. Lawrence) o contained very low levels ol both dicldriu and the DDT group, while seals from the Cabot Straits (Gulf of St. Lawrouoo) contained little dioldrin but higher DDT group residues, similar to thoso of Scottish seals. Of the few porpoises examined, that from Orkney was the least contaminated, but tho three taken on the eaet ooast of Scotland had markedly higher contents of all the rctiduce measured. One specimen contained a tola) rcsiduo con centration (diddrin and DDT group) of 73-3 p.p.m. Analytes of a few tieenos other than the blubber have been made, but concentrations in tho blubber have alwaya been found to bo the highest (Table 2). Concentrations in other tissues seem likely to be consistent with their lower lipid eontonts. - TabUS. Saiuplv Gray wat Gray ma) Gray stsl Gray acid OPorarpyowtwal TOTAL POT COXCR.VTSATIOM (p.p.m.) I* VANIOVS TH-SlK* Blubber Liver Basis KUIftty SpUsn Muarlv M 0-77 OI3 . _ 0 3S IMJ US 0-97 0*4 OSS 3-4 0-4A 0-17 0 15 3-4s aosisl 0o0v7: 004 0O-0ld6 OSS Tim proportion of blubber extractable by hexauu wav dotonnuieu for somo ssmplcv. Values ranged from 72 to 89 per cent (mean 80 par ont) for the Canadian aeols, and from 88 to 88 per cent (moon 93 por cont) for Scottish seals samples on the breeding grounds off tl>e west coast. (Values for other seal samples were not estimated.) Con centrations of pcatioides in terms of extractable fat for these samples would thus be up to 40 per cent greater than the values in Tabic 1, but tho general comparison is not significantly affected. The lower extraoteble fat values for tho Canodioit samples may possibly be a result of being preserved in formalin. Concentrations of pcsticido residues in the extractable fat of various organs and tissues of one porpoiso show an important relationship (Table 3). While tho concentra tions of the DDT group in tho original tissue* vary widely, those expressed iu terms of extraoteble fat arc in mueh olotcr agreement, with the sole exception of the brain. A similar anomaly for tissues of trout was described by Holden".. It seems likely that a large proportion of the lipid fraction of tho brain may not contain pesticides, and the brain lipid composition is known to differ considerably from that of depot fat. Tw* 3. cosctxTRinosF or tut*l dot (p.p.m.) is riMiriu or a roHrouc Thaw or orytui niubber MwcU Uvr 3|A*n Kidney Btsls Concaiitr*tlmintliM 3-3 0-36 063 0-13 004 0-03 ftreeutase exUru-t- 37-0 3 1 13-3 4-1 14 S3 bte fat ConoentfMiloa is 5-3 0 2 4 3 2-4 9-3 0*7 estfiu-fahlr fat Tito unidentified peaks on the chromatogram* loom to be similar to those produced by polychlorinated bi phenyls and, to enable comparison to be made, the ratios (Rx) of the retention times of all regularly occurring poak* (relative to diddrin 100) have been calculated for the operating oolumn temperature of 200* C, these values being temperature-dependent. The Rx values of PCB compounds from commercial PCB formulations were also determined for both types of column (Table 4). At least seven PCB-type peaks were found, including those which interfere with p.p'-TDF. and p.p'-DDT. Heptachlor epoxide and p,;'-MDE could not be confirmed on both columns and arc not therefore recorded. * The most significant aspeot of the results is that, although seals and porpoises inhabit an environment far removed from the site of application or discharge of pesticides, they can contain much greater concentration# of dteidrin and DDT group residues than thovc recorded for most other species, including nun. Robinson and Hunter1* found a mean concentration of dieldrin of 0-2)* p.p.m. (range O-lfr-O-73 p.p.m.) and a meat) total con- MONS 082904 oo eontrntiou of DDT of 4*0 p.p.m. (range I-O- IM p.p.m.) in samples of human dopot fat >u England in 1804. Mo evkloneo of any significant chango was found during 1903-65. Table . asbATiva airsMioir vum (R) or nsatnwn# (uiblprik- 100) DC>t00 oelwan iXMOO/QF-1 ootuma . -170 :lU 585 p.p'-DDS OleMrin -100 ,p*-TDE -131 PCB -I3 pob -lies .'-DDT kd --1m47 PCS -1SS 100 Itl " The hirU and poipoiivi from the eaet const of Scotland wore usually more seriously ooutamiuatod than those from the north and west coasts. This, st least in res^eet of seals, may be beoauso, as is believed, the populations in tlie two areas come from different breeding sites. The soais south of Aberdcon breed principally on the Fame Islands, oil the north.oast ooaet of England, while the seals of north and west Scotland aro primarily from tho breeding grounds of tho Orkney Islands In the north, and otliorislands off tho west coast of Sootland. The sea oil eastern Seotlend ie also likely to reoeive more con tamination from estuarine discharges than that off north and west Sootland. Similarly, the two separate seal populations sampled off the east ooast of Canada may Inhabit areas with different levels of contamination. Pups oontain peetioidc residues in concentrations only slightly lower than hi the parent population Common seals in Holland have boon found with concentrations of residue similar to those of soais on (ho Scottish east coast1*. While the residue concentrations in subcutaneous fat aro high, thooe of other tissues and organs are found to bo much lower. This suggests that there is no risk of physiologies! effects, unless the motabolism of ranoh of the fat in times of stress lead* to a considerable increase fan tho concentration of the residue In circulating lipids, and thus in .residua concentrations In other organs or tissues. Grey seals on tne coast of the Scottish nuiiuhiml fwd primarily on salmon (Salnio talar) and cod (fathtt morrhita)1*. The highest concentrations of pesticide in selmonids in tho marine environment have so for been found in soa trout (S. trutta) on the tost coast with up to 0-3 p.p.m. (dieldriu + total DDT) in muaolo tissue", and salmon frora the same area would probably liavo similar contents. Cod examined from tho east ooast havo eon. tained up to 0-35 p.p.m. (dioldrin 4- total DDT) in muscle tissue (mean 0-12 p.p.m.) and from the west ooast np to 0-6U p.p.m. (mean 0-z2 p.p.m.), while eod livers oontained up to 4-0 p.p.m. and 12-0 p.p.m., respectively. Groy smile are estimated t o eat about la lb. of food daily, und thus an adult seal could ooneume its own weight in food in 20- 30 days. Assuming a high proportion of the pesticide intako to bo stored in body fat rather than to be excreted or metabolized, an incroase of two orders of magnitude in poetioide concentration from food to body fat within a few years ie feasible. This degree of accumulation of residue in an environment not deliberately contaminated, and in species eoologically far distant from the target organisms of persistent pesticides, underlines (lie im possibility of oonfining such chemicals to the areas of application. Wo thank Dr B. B. Rno for obtaining tho Scottish samples, and Dr C. J. Kerswill for tho Canadian samples. Received December 16.1M7. tees). TaMon. j. O'O.. and Ruiteka, J. H. A.. .Yctiirr.tll. 34# IIMT). * Moore, X. W., aad Tntton, J. O'O.. 107. *1 (IMS). * KoblnMU. J.. Btchnnleon, A.. Crabtree, A. X.. Coukon, J. C.. mhI Potte, 0. R.. .Y*Imm. 114.1307 (1907). - * Department of Astteultiu* and Plftertee (be Scotland, KIMwrlre of Scot land. Report (bit 1CS6. ' Dowvrlmtnt of Asriculture and Fltheriee for Scotland, Fltheriee ot Scot land. Report fbr 19SS. ' De Paubert Maunder, M. J., Sees. H., Oodly. R. W., Hammond, E. W'., Rnburs. J.. and Thornton,X, JntUpH. IS, IS# * JeoMD. S.. iYm SeUnliM, St. SIS <ISM). * HolDtet,D. C.. Simmons. J. H,,and Tattoo. J. O'O.. 337 (IM7>. > Slmmoaa, J. H.. and Taktos. J. O'O.. J. CArMwfer.. *7,161 (1M7). Holden. A. V., tan. Jppt, AM., SO, 4S7 (IMS). v Robinson, J.. and Hunter, C. O.. Anh, Entirm. BmKA. M. 64S <tN*>. Kosmaa, J. H., and van Condemn, H,, Appt. Enl., I (S*r>P*.). SO (ItoS). * Xss, B. B.. Jtv. R**., Xo. 9,99 <1S0). ' Holden. A. V., J. Appt. Em.. S (SuppM. 4ft (ISM). 1 HONS 082905 t*rb>u<> In (*me itiulo'b* Flhrt. Kotitu a Co., ltd. St. AIHm*.