Volume 6/Number 3/Match 1975

ported by the Federal Water Quality Administration contract No. 14-12-874 to Dr. Peter W. Glynn, and was carried out in the laboratories of the Smithsonian Tropical Research Institute.

208 Life Sciences I, The Pennsylvania State University, University Park, PA 16802, U.S.A.

AMADA A. REIMER

Atema, J. & Stein, L- S. (1974). Effects of crude oil on the feeding behavior of the lobster Homarus amerieanus. Env. Pollut.. 6 77 -86.

Birkeland, C. E., Reimet, A. A. & Young, J. R. Effects of oil on tropical shore natural communities in Panama. EPA Report Contract No. 14-12-874 (unpublished).

Bluroer, M., Sanders, H. L., Grassle, J. F. & Hampson, G. H. (1971). A small oil spill. Environment, 13, 2-12.

Dick, B. (1973). Some effects of Kuwait crude oil on the limpet Patella vulgat~ Enr. Pollut. 5, 2t9-229.

George, J. D. (1970). Sub-lethal effects on living organisms. Mar. Poilut. Bull. 1,107-109.

Grant, E. M. (1970). Notes on an expe.-Sment upon the effect of crude oil on live corals. Fish. Notes (N.S.) Dept. Primary Industries Brisbane, No. 1, 1-3.

Johannes, R. E. (1972). Coral reefs and pollution. In: Mar/he Pollution and Sea Life, ed. Ruivo, M. London: Fishing News (Books) pp. 364-375.

Johannes, R. E., Maragos, J. & Coles, S. L. (1972). Oil damages corals exposed to a.it. Mar. Poilut. BuR 3, 29-30.

KJttredge, J. S. (1973). The effects of crude off pollution on the behaviour of ma,d_ne invertebrates. Gov. Rep~ Annourt, 73, 78.

Lerthoff, H. M. (1968). Chemical perspectives on the feeding response, digestion and nutrition of selected coelenterates. In: Chemical Zoology, ed~ Florkin M. & Scheer, B. T. Vol 2, pp. 157-221. New York: Academic Press.

lewis, J. B. (1971). Effects of crude off and off-spill dispersant on reef corals. Mar. Pollut. Bull., 2, 59-62.

Mariscal, R. N. & Lenhoff. H. M. (1968). The chemical control of feeding behaviour in Cyphastrea oce//ina and some other Hawaiian corals. J. exT,. BioL. 49,689-699.

Smith, J_ E. (1968). Torrey Canyon Pollution and Marine Life. Cambridge University Press.

Straughan, D. (1970). Redressing the balance on the reef. Mar. Pollut. BulL, 1, 86-87.

Observations on the Distribution of Dissolved Mercury in the Ocean

The concentration of dissolved mercury in sea water has been determined in a number of areas in the northern and southern hemispheres and an attempt has been made to correlate the values found for certain areas with natural physical phenomena. The average concentrations found ranged from 11.2 ng 1 -x in the southern hemisphere to 33.5 ng 1-1 for the northern hemisphere; an increase suspected to be the result of dispersion of industrial pollution by jet streams. Local effects including upwelling, volcanic action, land run-off and heavy suspended matter loads are also discussed.

Although there has been a recent upsurge in interest in the environmental chemistry of mercury, as a result of tragedies brought about by the consumption in Japan of fish polluted with methyl mercury, little detailed in- formation is available about the distribution of th~ element in the sea (see Fitzgerald et at., 1974). Because of dif- ferences in sampling and analytical techniques it is difficult to compare the results obtained by different workers (which range from 0 to 364 ng 1 -t) and to look for variations which are caused by geographic factors or by man's activities. Examination of snow cores from Greenland has provided some evidence that the level of anthropogenic mercury, in the environment has increased in recent years (Weiss et al.. 1971). According to Klein & Goldberg (1970) the flux from domestic and industrial activity, (e.g. the bumJng of fossil fuels and cement manufacture) now approximately equals the natural flux from weathering, vulcanism and degassing of soils. However, it is not known to what extent if any these additional sources of input have affected the levels of mercury in the mixed layer of the sea in which it probably has only a short residence time because of its affinity for suspended matter (Lachet, 1972; Gardner & Riley, 1973a, b) and for plankton (see e.g. Windom et al., 1973). The present paper describes work which has been

carried out in an attempt to gain some insight into the factors controlling the geographical distribution of mercury in the sea. Most of the sampling programme was carried out on board commercial ships en passage to the far east and West Indies.

E x p e r i m e n t a l All samples except those from the English Channel and

Icelandic waters were collected by pumping from a depth of 2 m, while the rest were collected with an 8.5 1. NIO polypropylene sampling bottle. All samples were filtered through 0.45 /am Oxoid f'tlters. Storage of samples was carried out after acidification to 0.2 N with sulphuric acid using 2.5 1. glass bottles which had been acid washed, coated with silicone off and baked. Aliquots (2 1.) of the samples were analysed as described by Gardner & Riley

(1974).

Resul ts Sampling was carded out at 75 stations in all and at 10

of them depth profiles were determined. The positions of the stations are indicated in Fig. I and the results of the analyses of surface samples are shown in Table 1; those obtained in depth profiling are presented in Table 2.

Discussion In general the results obtained for both surface and deep

waters are similar to those obtained for very restricted areas by several recent workers using a variety of techniques (see e.g. Burton & Letherland, 1971 ; Leatherland et al., 1971; Carr e ta / . , 1972: Topping & Pirie, 1972; Fitzgerald et al., 1974: Olafsson, 1974). An attempt has been made to examine the results on a regional basis and for this purpose the stations have been divided into a number of geographic categories, the mean results for these zones are shown in Table 3. The most notable conclusion which can be drawn

43

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from these data, using the standard error of the difference test, is that all samples from below northerly jet stream paths and adjacent latitudes contain significantly (P > 99.8%) greater concentrations of mercury than do those from other areas. Thus, waters from the sub-tropical North Atlantic and the East China sea, underlying the sub-tropical stream contain on average 33.5 and 28.4 ng I -I respectively in contrast to an average value of 15.9 ng i -I for waters from regions not associated with jet streams. Similarly, high values (ave. 26.1 ng l - l ) are to be formed in Icelandic coastal waters, which is slightly north of the polar front jet and in the polar night jet stream. These f'mdings are in agreement with the suggestion by Goldberg (1975) that the jet streams carry pollutants from the industrial areas of the northern hemisphere in a concentrated band around the globe, and that these pollutants are subsequently pre- cipitated beneath it. The mean of the 14 samples analysed from English coastal waters that lie directly below the northern polar jet stream is 21 ng 1 -l . Although high in comparison to those means calculated for non-jet stream influenced zones, it is lower than the means mentioned above. One might assume that these coastal waters (and also those of the East China Sea and Malacca Straits might have a greater dissolved Hg concentration contn'buted not only from the atmosphere but also from localized land run-off.

44

However the greater average load of suspended matter in this area (8133/zg 1 - l ) and the aff'mity of the metal for it, could explain this fall in Hg levels whereas in the case of the East China Sea the localized contribution from Japanese industry must be greater than losses onto the particulate matter present (ave. 1557/zg l-l.)

An area that lies in the belt of the jet streams that appears to deviate from the above pattern is the N.E. Atlantic coastal zone, which has a mean of ordy 14.7 ng 1 -I Hg. Th~ is a zone of upwelling (deep waters brought to the surface contain higher levels of mercury as well as being rich in nutrients) that periodically supports dense plankton populations that could have stripped the dissolved mercury. from the water. The metal might then have been bio- concentrated by grazing organisms of higher trophic levels. In this connection it is interesting to note that in a previous survey (Chester et al., 1973) two stations in the same upwelling zone showed only traces of dissolved mercury (< 1 ng 1 - l ) indicating that almost complete removal is possible if the bloom is heavy enough.

A further factor could influence the distribution of mercury is volcanic action which could produce local and world.wide effects depending on the severity of the eruptions. However Lamb (1970) reports that in recent years there has been no sLm'dfic~t volcanic activity in the

Volume 6 / N u m b e r 3/March 1975

T A B L E I Mercury concen t ra t ions in surface samples

TABLE 2 Mercury concent ra t ions o f depth prot-des in N. At lant ic (March, 1973)

Wt of Hg mspended

Sm Position conc'a matter No. Long. Lat. Date Area" (ng/l) U2g/l)

I 18°55.5'S 60°40.0'E 8. I 1.72 IO 20 12 2 06°33.5'S 78°II.0'E 12.11.72 IO 20 38 3 05°47.0'N 96°35.0'E 16.11.72 MS 70 90 4 07°51.0q~ I03°12.0"E 24.11.72 SC5 6 72 5 12°19.0'N I00°47,0'E 30.11.72 SCS 20 171 6 17°33.5~N 113028.0'E 4.12,72 SCS 25 72 7 22° 13.0"N 114°39.0'E 9.12.72 ECS 45 4364 8 29053.5'N 124°49.0rE 11.12.72 ECS 17 1596 9 33°57.0 'N 130°57.0'E 14.12.72 ECS 31 1567

10 27°54.0 'N 130°34.0'E 25.12.72 ECS 31 231 11 20°58.0 'N 121°34.5'E 27.12.72 ECS 18 26 12 07°47,0'S 73°.54:00E 13. 1.73 IO 6 II 13 27°24.0'S 42°15.0 'E 19. 1.73 SWO 10 36 14 34°10.5'S 25°28.5'E 22. 1.73 SWO 6 123 15 29°40.0'S 13°59.0"E 24. 1.73 SEAO 6 76 16 10°31.0'5 01°35.0 '9/ 28. 1.73 SEAO 6 23 17 00°56.0'S 08°52.0'W 30. 1.73 SEAO 18 36 18 08e54.0,'N 16°03.0'W i. 2.73 NEAO 20 57 19 19°55.0'N 17°56.0'W 3. 2.73 NEAO 7 213 20 48°05.0rN 12o30.0'9 , 27.10.73 AO 52 ND 21 42°40.0 'N 20°30.0"W 28.10.73 AO 21 ND 22 38°35.0~I 26°50.0~ 29.10.73 AO 27 ND 23 35°50.0 'N 32025.0'W 30.10.73 AO 42 ND 24 32°40.0qq 3~P20.0"W 31.10.73 AO 54 ND 25 30020.0'N 45°00.0 'W 1.11.73 AO 2.5 ND 26 27°30.0"N 5(P20.0'W 2.11.73 AO 30 ND 27 24°20.0 'N 56°40.(YW 3.11.73 AO 38 ND 28 21°40.0~ 62°50.0'W 4.11.73 AO 10 ND 29 17°50.0'N 68°I0.0'W 5.11.73 AO 36 ND 30 40°35.0"N l Je00 .0 'W 6. 4.73 NEAO 9 222 31. 23°03.0q~I 17°24.0'W 9. 4.73 NEAO 18 307 32 03°00.0 'N l l° IS.0AV 13. 4.73 NEAO 34 86 33 15°17.0)S 02°31,0 'E 17. 4.73 SEAO 15 6 34 33°33.0'S 28°27.0rE 23. 4.73 SW'IO 7 48 35 25°49.0'S 49°45.0 'E 27. 4.73 SWIO 12 25 36 12°46.0'S 69°37.0tE I. 5.73 IO ii II 37 01°17.0'S 83°37.0'E 4. 5.73 IO 34 19 38 05°37.0 'N 99018.0'E 7. 5.73 MS (N) TR 104 39 11°22.0'N 101°25.0'E 19. 5.73 SCS 14 31 40 04°57.0 'N 108°00.0'E 26. 5.73 SCS 7 9 41 09°04.0 'N I18057.0rE 30. 5.73 SCS 37 31 42 19o09.0'N 116°33.0'E 4. 6.73 SCS 7 93 43 15°09.5"N I12°57.0'E 9. 6.73 SCS 11 515 4.4 01°25.0'N I03008.01E 15. 6.73 SCS 17 606 45 06°34.5'N 91°55.0rE 22. 6.73 IO 18 142 46 01°44.0 'N 77°12.0'E 1. 7.73 IO 17 64 47 06057.0'S 68°50.0 'E 3. 7_73 IO 20 101 48 14035.5'S 58e35.5'E 5. 7.73 IO 35 65 49 30°42.5'S 34°08.5 'E 10. 7.73 SWIO 21 - 50 16°57.5'S 03°16.0 'E 16. 7.73 SEAO 25 236 51 42°53.0 'N 09°52.0'W 28. 7.73 NEAO TR 133 52 52°44.0 'N 05° I I . 0 'W 30. 7_73 ISEC I0 412 53 50°I0 .0 'N 04°20.0"W - 9.73 ECEC 21 - 54 50°01.0rN 04°26.0rW - 9.73 ECEC 15 - 55 49~39.0.rN 04°40.0~Y - 9.73 ECEC 35 - 56 49°30.0 'N 04°40.0'W - 9.73 ECEC 10 - 57 49°20.0,'N 04°40.0"W - 9.73 ECEC 23 - 58 48°39.0 'N 05°38.0"W - 9.73 ECEC 5 - 59 49030.0rN 05°36.0'W - 9.73 ECEC 14 - 60 52~01.0'N 5°00.0'W - 2.73 CSEC 80 10434 61 49°58.0rN 7°24.1%V - 2.73 CSEC 19 - 62 52°18.9-'N 6°07.0'W - 2.73 CSEC 17 11044 63 50°56.5"N 6°48.7'W - 2.73 CSEC 9 9516 64 51025.0,.'N 7°41.4'W - 2.73 CSEC 21 - 65 50°29.2 'N 5°57.3'W - 2.73 CSEC 15 9257

*Area key: IO = Indian Ocean; MS = Malacca Strai ts; SCS = Sou th China Sea: ECS = East China Sea; SWIO = S.W. Indian Ocean; SEAO = S.E. At lant ic Ocean; NE AO = N.E. At lant ic Ocean; AO = At lant ic Ocean; MS fN) = Malacca Straits (North) : ISEC = Irish Sea -Eng l i sh Coastal; ECEC = English Cha rme l -Eng l i sh Coastal; CSES = Celtic Sea-Engl . ish Coastal.

Mercury Stn Position Depth concn No. Lat. Long. Water mass (m) (ng 1 =l)

66 67000.0rN 13°58.0J~V arctic 0 41 67°00.0'N 13°58.0"W arctic 100 68 67°31.0'N 13°58.0'W arctic bottom 275 142

67 67°31.0'N 13°20.0"W arctic 0 83 67°31.0"N 13°20.0'W arctic 100 47 67°31_0'N 13°20.0'W arctic bottom 300 18 67°3 I.O~N 13°20.OtW arctic bottom 600 36

68 68°30.0'N 12°08.0'W arctic 0 20 68° 30.0rN 12°08.0~ arctic I00 13 68°30.0"N 12°08.0'W arctic bottom 300 30 68°30.0~I 12°08.0'W arctic bottom 600 7

69 66°24.0'N 18°50.0'W arctic 0 25 66°24.0"N 18°50.0"W arctic 50 10 66°24.0'N 18°50.0"W arctic intermediate 200 8 66o24.0"N 18°50.0~W arctic intermediate 415 10

70 66°44.0q~I 18°50.0'W arctic 0 8 66°44.0 L'N 18°50,0'W arctic 50 27 66°44.0~N 18°50.0~W arctic 200 15 66°4-4.0~N 18°50-0"W arctic intermediate 400 7 66°44.0'N 18°50.0rW arctic bottom 680 6

71 67°22.0'N 19°00.0'9/ arctic 0 18 67°22.0"N 19°00.0"W arctic 50 10 67°22.0'N 19o00.0'W arctic 200 12 67°22.0"N 19°00.0'W arctic 435 13

72 63°27.09'N 20°14.30"W atlantic water 0 12 63°27.09'N 20°14.30'W atlantic water 5 17 63°27.09'N 20°14.30"W atlantic water 15 9 63°27.09'N 20°14.30"W atia.nuc water 35 9

73 63°26.35'N 20°12.27~ atlantic water 0 42 63°26.35~ 20°12.27'W atlantic water 5 19 63°26.35,'N 20°12.27'W atlantic x~atet 15 25 63°26.35'N 20°12.27'W atlantic water 30 9

74 63°24.28'N 20°14.35'W atlantic water 0 8 63°24.28'N 20°14.35'W atlantic water 10 58

75 63°07.0'N 19°54.0'W atlantic water 800 4 63°07.0'N 19°54.0'W atlantic water 0 4

northern hemisphere apart from volcano Surtsey on the Island of Heimaey which erupted in 1963, 1965 and 23 January 1973. Emissions from the latest eruptions were still heavy during the sampling programme around Iceland in February and March, 1973. It was thought that this might have affected the mercury levels in waters adjacent to the Vostmanns Islands but only two samples (with 42 and 58 ng I -i Hg) were significantly different from those of other North Atlantic waters. Only slight increases have been found for thisarea by J. Olafsson (private communication). A speculative interpretation of the other high concentra- tions found for the surface waters to the north east of Iceland is that they are the results of precipitation of volcanic emissions which have been transported there by the prevailing south westerly winds. In agreement with earlier observations (Gardner & Riley, 1974) the Arctic Bottom Water to the north east of the island was again found to contain a concentration of mercury (142 ng l -x) almost an order of magnitude greater than average. These water pockets which have high concentrations have pre- viously flowed over the North Atlantic Ridge (Steffmsson, 1962) where the mercury could have been leached from relatively fresh lava deposited from fissures along this fracture zone. On the other hand the mercury could have originated from the melting ice (Weiss et al., 1971) in the extreme north where these deep, cold, less saline waters are formed.

45

TABLE 3 Mean mercury concentrations and factors p(y'~ibly

influencing each zone

Zones

Mean wt Factors poss, bly Mea~ H8 ruspended influencing each

S/Inorts conch Sai ler Zorie÷ included (ug 1 -i) (#gL -t) I 2 3 4 5 6 7

E. China Sea 7 - I 1 28.4 1557 + S. China Sea 4 - 6 . 3 9 - 4 4 16 177 Indian Ocean 1.2.12,36,371

45 -48 20, I 51 S.W. [ndean Ocean 13.1434,35,39 11.2 58 S. 1:. Athmtic Ocean 15-17.33.50 14 75 N.E. Atlanttc Ocean 18,19.30-33,51 14.7 [55 Subt[ol)tctl

N. Afl~mnc Ocean 20-29 33_5 ND ° + Eni/iah coar',~

waters 52-65 21 8133 Malacca Sis_ 3.38 (35) 97 Icelandic co~[~

waters 66-75 26.1 ND*

4-

÷

÷

÷ ÷

• The very low levels of suspended matter could not be accurately meamred from 2 I. of ~a Wiles.

~'(1) N. Subtropical jet su~am; (2) S. Suburopical jet stream; (3) Polar front jet stream; (4) Polar night jet stream; ~5) Upwelling; (6) C o u t t l run-off; f7) Voicamc tcuon_

C o n c l u s i o n The northern jet streams appear to be carrying mercury

from the large industrial conurbations o f U.S.A., Europe and Japan and redistributing it in a belt below their path- ways, causing increases in the mean mercury concentrations of surface waters that are urtlikely to have been polluted by any other means, e.g. the North sub-tropical Atlantic. At isolated stations local effects, including land run-off, high suspended matter loads and volcanic action can cause anomalies in general trends. In the equatorial regions and the southern hemisphere anthropogenic pollution is only slight and an overall mean for these areas o f 15.9 ng 1 -t is found in contrast to 26.5 ng 1 -t for areas influenced by the northern jet streams. Perhaps the average mercury concen- tration o f 11.2 ng 1 -~ found in an area such as the S.W. Indian ocean which lies below the relatively unpolluted southern jet stream belt, which is not subject to upwelling, to land run-off or volcanic action, might be considered as a natural b a c k g o u n d level for dissolved mercury in the oceans, (this is almost an order o f magnitude less than the value often quoted).

The author would Lt~e to thank Mr. J. Olafsson of the Marine Research Institute, Reykjavik for the collection of the Icelandic samples and colleagues Mr. A. I. Murray, Mr. P. D. Jones, Dr. R. C. Padgharn, Mr. K. J. Connor, Mr. J. Lee and Mr. A. Griffiths, for collection of other samples, in addition she is grateful to the Blue Funnel Line (Ocean Transport and Trading) and to T. & J. Harrison Ltd., for permission to make collections from thei: ships. Thanks

Manne Poilu don Bullem~

are also due to Professor J. P. Riley and Natural Environment Research Council for arraa~men[ of financial support.

DORIS GARDNER* Department o f Oceanography, Universi~. o f Liverpool, P O. Box 147, Liverpool, L69 3BX, U.IC

*Present address: CSIRO, Department of Fisheries and Ocean- ography, Cronuila, N.S.W. Australia.

Burton, J. D. & Leatherlaad, T. M. (1971). Mercury in a coastal marine environment. Nature, Lond,, 231,440-442.

Carl R. A., Hoover, J. B. & Wdkni~ P. E. (1972). Cold-vapour atomic absorption analysis for mercury in the Greenland Sea. Deep-Sea Res-, 19,747-752.

Chester, R., Gardner, D. Rlldey, J. P. & Stoner, J. (1973). Mercury. in some surface waters of the world ocean. Mar. Poilut. Bull, 4, 28-29.

Fitgerald, R. A., Gordon, D. C. & Cranston, R. E. (1974). Total Mercury in sea water in the northwest Atlantic Ocean. Deep- Sea .~es., 21, 139-144.

Gardner, D., & Riley, J. P. (1973a). The distribution of dissolved mercury in the Irish Sea. Nature, Load., 241,526-527,

Gardner, D. & Riley, J. P. (1973b). The ~ b u t i o n of dissolved mercury in the Bristol Channel and Severn Estuary. Estuar. Coastal Mar. ScL, I, 191-192.

Gardner, D. & Riley, L P. (1974). Mercury in the Atlantic around Iceland. J. Cons, Int. Explor. Met., 35, 202-204.

Goldberg, E. D. (1975). Marine pollution. In: O1emz'ca/ Ocean- ography, eds. Riley & Skirtow. London: Academic Press, (in press).

Klein. D. H. & Goldberg, E. D. (1970). Mercury in the Marine Environment. Environ. Set Technol., 4, 765-768.

Lachet, B. (1972). ~6tude Cin~tlque au laboratoixe de I'dputation d'une eau de Rivi~re) (ls~re) par des s~limenu en suspension. Radioprotection. Dunod, 17, 143-157.

Lamb, H. H. (1970). Volcanic dust in the atmosphere with a chronology and usessment of its meteorological significance. Ph//. Trans- R. Soc. /,on., 266, 425-533.

Leatherland, T. M., Burton, J. D., McCartney, M. J. & Culkin, F. (1971). Mercury in northeastern Atlantic Ocean water. Nature, Lond., 232, 112.

Olafsson, J. (1974). Determination of nanogzarn quantities of mercury in sea water. Anal. G~im. Acta., 68,207-211.

Stef[nsson, U. (1962) North Icelandic waters. Rit Fixldde~dar, Vol. iii, 269 pp.

Topping, G. & Pixie, J. M. (1972). Determination of Inorganic mercury in natural waters. Anal. G~im. Aeta., 62,200-203.

Weiss, H. V., Koide, M. & Goidberg, E. 13. (1971). Mercury in a Greenland ice sheet: Evidence of recent input by Man. Science, N. Y. 174, 692-694.

W'mdom, H., Taylor, F., Stickney, R. (1973). Mercury in North Atlantic plankton. J. Cons- Int. explor. Mer., 35, 18-21.

Incidence of Polychlorinated Biphenyls in Clyde Seaweed

PCBs accumulate in seaweeds. This survey of concentrations found in fixed algae around the Firth of Clyde reveals a similar pattern of PCB distribution to that found in mussels.

Considerable evidence suggests that PCBs are globally distributed throughout the aquatic environment by a number of modes o f transport (Abbot t eraI., 1965, 1966; R.isebrough et aL, 1968a, b; Sodergren, 1972). Despite their low solubility in water, PCBs have been detected in British coastal waters in mussels (Waddington & Mackay, 1972; Holdgate, 1971), ~ e y seals, porpoises (Holden & Marsclen,

46

1967), shrimps (Holdgate, 1971) and plankton (Williams & Holden, 1973). PCBs have also been determined in marine organisms in the River Clyde estuary and the Irish Sea (Holden & Marsden, 1967; Williams & Holden, 1973). Since PCBs are difficult to degrade in an aerobic environment (Holden, 1970), it appeared important to investigate the possibility that marine organisms and plants could act as reservoirs o f these substances.

The large amount o f seaweed present around the Clyde estuary shores prompted the authors to analyse represent- afire samples ¢rom the area for PCB residues.