Document 8zDNG8yMV5eexZLe1Oky20b5

24S- NATURE VOL. 224 OCTOBER . 18 1969 and yp'-DDT) wero also analysed. Recovery was abovo A TYPE Or ORGANISM INVESTIGATED ACCORDING TO THE LOCALITIES 1 Mtissel 2 Herring 3'Piri'ce f* : 4 PicLcd Dogfish 1 5 Cod ; 6 Salmon ! 7 Sea! ./ 8 Guillemot eggs 190 .Wh.ite.-t.ol.led Lo.g.ie 11 Heron 80 por cont, but as normal in rcsiduo analysis5 wo made no correction. ' The mean figures in Tabic 1 ar 2d lront average value of each locality within the four regions. ` The rcsiduo values are based both on fresh tissue and on hexane extractable fat. Tho figures for fresh tissue are comparable with reported values from otiior countries. Wo boliovo, however, that tho fat values are of particular interest from an ecological point of view. Fat is important in tho transport of energy and as a carrier of tho residues between tho species in the food chain. Furthermore, there is a groat seasonal variation in fat content within tho populations. Tho difference- between the greatest and the smallest rcsiduo level in the extractable fat of individuals of ono species at a given time, in a given place, is less than in fresh tissue. The fat content of herring muscle, for oxamplo, varied from about 1 per cent in tho spring to about 10 per cent in the autumn. Our discussion wilh- thoreforo be based largely on residue levels in extractable fat. Mussols from tlio west coast of Sweden have lower nverago values of c DDT and PCB than from tho Baltic proper and tho archipelago cf Stockholm. Tho level of e DDT in mussels from tlio Dutch, West German and British coasts'-' lias an upper limit similar to that in mussels from tho Baltic proper and the archipelago of Stockholm. DDT contamination in individual plaice, cod and in fish oil is greater in tho Baltic proper, than off the west coast of Sweden, and there is little or no overlapping of the rcsiduo values. In the case of PCB, a plaice from the very polluted Idcfjord in the west coast, increases tho average value for tho west coast samples from 0-C3 to 5 p.p.m. Other individual samples of fish from tho west coast contain PCB residues of tho same magnitude a.;- rosiducs in specimens from tho Baltic. This may be the result of coastal contamination. Tho picked dogfish, which lives more in the open sea, seems to lia'-o the same ; amount of e DDT, but a. smaller amount of PCB than other fish from tho west coast of Sweden. The samples of herring from the Baltic proper, the archipelago of Stockholm and tho Gulf cf Bothnia had DDD was found in small concentrations, not usually largo residues of e DDT. No herring from the west coast more than 10 per cent of tho e DDT, in most samples. of Sweden has been studied. Recently wo analysed eight (e DDT stands for tho sum of DDT and DDE---DDE wa3 herrings from the west coast. On fat basis tho mean multiplied by 1-11 to correspond to the original DDT.) values were: e DDT, 1-9; DDT, Q-SG; and PCB, 0-75, in For seals from the archipelago of Stockholm and for salmon good agreement with the fish oil values (see Tablo 1). from the Baltic proper which had relatively largo amounts Juvenilo horring from tho Dutch Waudon Sea. (coastal of DDD, e DDT stands for the sum of DDT, DDE and waters)5,8 contained DDE residues in fresh tissue with an DDD. upper limit of tho same magnitude ns in herring from the Wo analysed all tho samples using gas chromatography Baltic area. and ` electron capture detection. Confirmations woro Residues of PCB and e DDT in one sample of fish oil carried out with double column systems combined with from tho southern Baltic proper wero about five to ten I treatments with sulphuric r.c;d and potassium hydroxide7. tirne3 greater than tho tlirco samples from the west coast AVo"found that the principal PCB components wero PCB of Sweden. Tho figures for the latter are similar. Tins . numbers 7--14 (low number is equal to a low chlorination is in accord with residues in fat in fish from tho respective degree), but tho mussels also contained tho lower areas. . *. numbers "the PC3 composition being similar to cloplion Ono herring from tho Sound had a much, larger.cement . i A 50). Tho PCB amounts given in Tablo 1 are, neverthe of PCB (23 p.p.m.) than tho herring from the res: of the less, tho sum of all PCB components found in the samples Baltic area.. This increased the average value in (his area although Urn relative amounts of the different numbers from 4-0 to C-S p.p.m. Cod and plaice from the Sound also vary. Thu results suggest that tho low PCB mnnhor.s had a larger PCB content, than specimens from tho Baltic are metabolized or excreted faster than tho higher proper and olf (ho west, coast. This suggests that there is .numbers, so that (.hero is an increase of tho latter its it local contamination of PCB in tho .Sound, Furthermore, passes through a fond chain. tho mean levols of PCI! noted in herring were .smaller An- attempt to cpuuit.itato PCB has boon made in in tho Gulf of Bulimia than in tlio rest of the Baltic. Sweden7, but because tho method is still rather rough (.ho The vagrant Baltic salmon had about, ten limes more values may la: correct only wilhin a factor of 2. Tho chlorinated hydrocarbons residue than a sample reported method is indirect because all the PCB components liave from Croat Britain5. not been isolated yet., and it is bused on a combination of The seals from tlio Bailie nropor, tho archipelago of mass spccf.roMinl.ry, micro-colorimetric and electron cap- Stockholm and tlio Gulf of Bothnia contained largo tore detection. For _ each twenty samples a blank amounts of residues of both e DDT and PCB. about ten On tliO fioJvcri mil a residuo-froc plaico sampio with addod times greater than amounts found in Cent Britain5. pesticides (lindane a'.driri, 7.7/DDE, dioldrin, 77/-DDD .Canada* and tho Netherlands1'*, One specimen iron; DSW 346682 STLCOPCB4084688