Document VKjgmpKvjbY13XJ7Mop4dRkYp

jumu 4Mmfitrrii (dikiimi'iiI Vnl. M. pp 777 7K' Prijxmon Plm 1974 pnnictl in Oiral Hcium ATMOSPHERIC TRANSPORT OF POLYCHLOROBIPHENYLS TO THE NORTH ATLANTIC* Ghiikii R. liMtvtY amt Wiu.iam G Sii.iniiaiii r Woods Mole Oceanographic Institution. Woods Hole. Massachusetts 02M3. USA (/`irvi rrrrtt'i'd 5 1913 <mJ in final form 72 Ntnvmher 1973) Abstract C oneentrattons of pohchloroluplienvls fPClts) were mcuMuvd in tlie atmosphere om lle wcstcin Nth Allaitlie. Holli the paniculate ami vapor phase were extracted, usmjj a tH'Wsamplei desigm-il lor this work. Previously PCB It vets tanged from $ ng m ' near the tuulhcuM coast of the M S. It' CMIS up in J on the Otand Banks. The PCB comentration in the utmospheie dcncascs expoiemiall) with distance from land It is concluded that wind trunsport is the nwjoi sourix ofclilotmati'il hydrocarbons in the oceans. INTRODUCTION Polyehlorobiphenyl (PCB) concentrations have been measured in the water and organisms of the open Atlantic Ocean (Harvey <'f al.. 1973). It has generally been assumed that POBs would be delivered to the open ocean mainly by the wind (Nisbel and Sarolim. 1972) simi lar to DDT(Scbu and Prospero. 1971) with fluvial and sewage inputs contributing smaller quantities (Corcoran and Lee, 1970: Holden. 1970). However, no atmospheric PCD measutements have been reported. Riscbrough (1972) was unable to detect PC'Bs on equa torial Atlantic dust collected on Barbados (Riscbrough t*f a/., 196K). Therefore, it seemed likely that PCUs were transported mainly in the vapor or aerosol phase and we set out to design a sampling system capable of trapping both particulate and vapor phase chlor inated hydrocarbons. Atmospheric PCB measurements were important to our studies because we had previously observed no inshore-open ocean gradient of PCUs in the mmface waters of the North Atlantic (Harvey vt al.. 1973). Thus, wc wished to determine if the atmospheric concentrations of PCB reflected this observation. In this paper wc present a new atmospheric sampling technique, and the results of our PCB measurements at four stations over the western North Atlantic. The sampling was performed during the first half of 1973. .. PROCEDURES The sampling system consisted ofa Hurricane Air Pump(Bendix Corp.) fitted with a 102 mm filter holder on the intake port. The exhaust pipe was fitted with several meters of extension so as not to interfere with the intake. A 0.3 /im glass fiber filter, which had been baked at ftXV for 12 h. was used on the intake. The filler holder chamber, behind the filler was filled with 1/4 in. ceramic saddles (distillation column packing. Fisher Scientific) which were coated with 0.25 per cent OV-17 silicone oil. The pump was run on low speed and generally achieved a flow rate of 22- 24 ftJ min' '. The saddles had to be cleaned initially by distilling several liters of water through a column packed with about 500 g of the commercial product. The OV-17 was purified by applying l.25g to the top of a 1.5 x 15cm column or sihea. Interfering impurities were Woods Hole Imiiiuiion Comrihulion No. 3l 73. 77H Giohci R. Hakvi v and Wu.liam G. Sti inuauik eluted with 80 cm3 of hexane. The OV-17 was eluted with 150 cm3 ofbetvcnc.Thc benzene solution was diluted with 100cm3 of hexane and 50()g of steam cleaned saddles were added. The solvent was evaporated to dryness on a rotary evaporatory at 50' with a water aspiratory. The coated saddles could be stored in glass jars or used immediately About 125g arc required to fill the filter holder chamber. Recovery of the chlorinated hydrocarbons from the coated saddles was accomplished by shaking with two l(X>cm3 portions of hexane in a separatory funnel. The hexane solu tion was dried with sodium sulfate and concentrated to 10 cm3 by distillation. 1 he extract was applied to the top 1.5 x I5cm column of silica and the chlorinated hydrocarbons were eluted with 80 tin3 of hexane. The hexane cluatc was concentrated to I cm' in a Kuderna-Danish concentrator. If necessary, the hexane was further concentrated with a stream of Florisil-purgcd nitrogen. No further cleanup was necessary before gas chromat ography. The concentrated extract was analyzed on a gas chromatograph equipped with a "'Nj electron capture detector.The column was a 2m x 2mm (i.d.) glass coil packed with a I: I mixture of 8 per cent QF-I and 2 per cent OV-17 on 100 120 mesh Anakronv The oven temperature was 190'. The chromatogram was quantified by comparing the heights of seven peaks in the sample with the same matching peaks in a standard of commercial Aroclor 1254 (Monsanto) as shown in Fig. I. The blank (a) was produced by leaving the entire apparatus at the sampling site for 24 h without running the pump. 1 lie saddles weic then extracted and chromatographed as described above. The sample chromatogram (b) Fig. I. Typical PON chiomatojsram of a Grand Hanks air sample (h|. The slami.ndi Aroclor 12*4 is shown in <cj and the Wank is shown m (a). The seven dotted peaks were used lot the quantification. MUN5 085734 Aimcuphcric transport of polychlorobiphcnyls 779 is from (he Grand Banks. The presence of (he PCBs was confirmed by pcrchlorination to dccachlorobiphenyl according to (he procedure of Armour (1973). The dccachlorobiphcnyl synthesized from the Bermuda samples was further confirmed by mass spectro metry Extraction of the glass fiber filters with hexane followed by concentration and chromat ography revealed PCB concentrations which ranged from undetectable in the Grand Banks samples to 0.04 ng m 3 in (he Vineyard Sound samples. The efficiency of trapping was tested by applying known quantities of 1.4.2`-trichlorobiphcnyl; 2.4.5.2,,4'.5'-l\cxacUlorohiphcnyl (AnaUibs. Inc.) or Aroclor 1254 (Monsanto Co.) on (he glass fiber filler. The average recovery after 20 h of pumping was 70 per cent for the pmc isomers or the mixture. The sampling stations arc shown in Tig. 2. Vineyard Sound (Massachusetts) samples were collected from the roof of the pilot cabin of the W.H.O.I. vessel R/V Asicrias. The Georges Hank collections were made from the 01 deck of the R/V Albatross /^(National Marine Fisheries Service). The Bermuda samples were taken from a 20-m tower on the south-west shore of the island. Finally, the collections on the Grand Banks were performed from the exploratory drilling rig Sctlneth 1 of Amoco Canada Ltd. at Station Razorbill. Procedural blanks from each station averaged 0.0.1 ng in' 3 for 500 m3. RF.SULTS The analytical results for the four stations arc set out in Table I. In addition, the DDT family (/-DDT) was detected in the Bermuda samples. The concentration of DDT in the four samples decreased from 5.3 x 10" u g m" 3 on 12 February, to 1.7 x 10' n g in'3 on 15 February (1971). The most likely source was the southeastern U S. cotton fields directly to Ihc west. At the other sampling sites the /-DDT concentration was less than 1 x 10' The PCB/i-DDT ratio was also found to be greater than 30 in the sur face water (Harvey ct til., 1973). The PCB concentrations were highest in Vincyatd Sound which lies only 150-250 km from the nearest windward industrial sources, i.e. the Boston Hartford New York New Jersey complex. The concentrations of PCB over the Grand Banks which are over 2000 km from the industrial complex of the northeast United Slates were 100 times less than in Vineyard Sound. In fact, when the average concentrations at each station arc plotted against the uvciagc distance of (he site from major industrial mons 085735 dttdKaMMr ->Ka^ 780 Gi.ohgi; R Harm v and Wiii.iam G. Sm inmauik Station Bermuda (32 2U'N; 64 4(1 W) (32"20N;64 40'W) (3220'N'.()4 40'W) Georges Hank (4l'4(rN; 67 3<>'W) (41`'40,N;(<7 30 W| (4I"40'N: 07 1(1'W| (41'40'N; <>7 30 W) (4r40'N;ft7'.WWt Vinevard Sound (41f'20'N; 70 SO W) Grand Hanks (45I6'N; 52-OH'W) (45"16 N; 52 08 W) (45*I6`N: 52' IWW| (4.VI6 N; 52'08`W) Table I. PCB concentration!. over the western North Atlantic Dale (1973) Sample volume (m`) Wind dircci ion 12 February 13 Februarv 14 February J 5 February 10 April 13 April 15 April 17 April 19 April 21 April 13 April 30 April 25 June 26 June 27 June 28 June 29 June 560 WNW 480 W 820 Variable 500 S 105 NW 675 NW 660 NL 655 NW 640 sw 650 sw 105 sw 224 sw 780 ssw 960 sw 840 wsw 940 wsw 540 w PCH np m 3 (calc as Amclor. 1254) 05 04 0.16 0.15 1.4 0.82 0.58 0.61 0.80 1.60 39 53 0.05 0.07 0 10 0 16 005 centers (Bermuda is equidistant from both northeast and southeast U S industrial com plexes) the seaward decrease is actually exponential (Kig. 3). Similar observations have been made for wind transport of industrial particulates over the ocean (I'olgcr. 1970) and bomb fallout over the United States after nuclear tests (Eisenbud and Harley, 1953). I t t t km (torn source Fig. 3. Relationship of atmospheric PCB and distance li oin industrial sources. DISCUSSION In our opinion the collection method used can only approximate the relative con centrations of chlorinated hydrocarbons in the particulate and vapor aerosol phase. Hyd rocarbons in the vapor or aerosol phase will easily pass through the glass liber filter and be trapped in the silicone ml at an efficiency similar to the spiking experiments. Hydrocar bons adsorbed on solid particles which arc trapped by the filler still have equilibrium *''*** 1,11,1 1 " 1 1 p HUNS 085736 \ pinlavc land oonlydand Tearrium Atmospheric transport ofpolychlorobiphcnyls ?g| vapor pressures with the surrounding air. At the high flow rates used these adsorbed hyd rocarbons could be entrained in the flow and swept into the vapor trap. The process is similar to that utilized in gas-liquid chromatography. However if we can assume that par ticulates arc being collected throughout the sampling period, the observation that only I per cent or less of the total chlorinated hydrocarbon concentration in the sampled air is found on the filler argues strongly against significant particulate transport. It seems likely that during the atmospheric lifetime of chlorinated hydrocarbons the vapor, aerosol and particulate states will equilibrate and exchange many times depending on temporal meteorological parameters. Thus, the state in which they happen to be cap tured at a particular geographical location is relatively unimportant to considerations of total atmospheric transport. Thus, the concentrations reported in Table I should be regarded as total PCB m"3. The strong dilution and fallout gradient observed over the western North Atlantic is not reflected in the surface water concentrations. However, since the highest con centrations of suspended matter arc in coastal waters (Manheim et <i/,, 1970) adsorptive scavenging by organisms and sedimentation must deplete these waters of dissolved PCBs at rates comparable to the delivery. In contrast, only a small fraction of the discharged PCBs reach the open ocean, but that which does must remain dissolved in the surface waters for a long time because of the low concentration of suspended mailer and the slower sedimentation rate. The result of these processes is that the concentration of dis solved PCBs from near shore water and the open sea is about (he same (Harvey et al., 1973). Sediments should reveal a gradient of PCBs from inshore to the abyssal plains. Analyses of bottom feeders support this prediction (Harvey et al.. 1974). Since the relative unimportance of river transport of chlorinated hydrocarbons has been noted (Seba and Prospero. 1971; Hartung and Klinger. 1970; Corcoran and Lee, 1970; Seba and Corcoran. 1969) wind transport is (he major source of chlorinated hydrocarbons in the oceans. Acknowledgements- We thank Drs. R. Dtice and T. Bidlcman. University of Rhode Island for permission and assistance in using their Bermuda tower. Dr. M. Grossiein made space available abourd HIV Albatross IV. National Marine fisheries Service. We arc especially grateful to Mr. G. Mcdicros for collecting the samples on Albatross IV. Finully. we are indebted to Mr. Neil Greer (Amoco Canada Ltd.) foi making au-umnioduuons available on the Sedwth I. This work was supported by the Inter national Decade of Ocean Exploration. National Science Foundation. Grant GX-352t 2. REFERENCES Armour J. A.(1974)Quantitative perchlormalion of polychlorinated biphenyls as a method for confirmatory resi due measurement and identification. J. Assoc. Off. Aqrk. Cht-m. (in press). Corooran I:. I\ and Lee C. C. (1970) The distribution of chlorinated hydrocarbon pesticides in the Mississippi River Delta and adjacent Gulf of Mexico. Paper presented before American Chemical Society, 4 December. New Orleans. Louisiana. P.iienbiid M. and Haiti) I H ()9S3) Radioactive dust from nuclear detonations. Science 117. 141 147 Folgcr D. W. (1970) Wind transport of land derived mineral, biogenic and industrial matter over the North Atlan tic. Deep Scu Res. 17, 3.17-332. Hartung R. and Klinger G. W. (1970) Concentration of DDT by sedimented polluting oils. Environ Set. Technol. 4,407 410. Harvey G. K.. Sictnhnucr W. G. and Teal J. M. (1973) Polychlorobiphcnyls in North Atlantic Ocean water Science 180, 643-644. Harvey G. R . Miklas II. P,, Bowen V. T. and Stcinhauer W. G (1974) Observations on the distribution of chlor inated hydrocarbons in Atlantic Ocean organisms. J Mur. Res. (in press). Holden A. V. (1970) Source of polychlorinutcd biphenyl contamination in the marine environment. Nature 22H, 783 784. TSfirT?" MONS 0B5V37 I 782 Guoaut: R. Hah vi:y and William (j Sytinhaulk Mtnheim f'.T. Meade R. H. and Bond G. CM 1970) Suspended mane? in surface waters of the Atlantic continen tal margin from Cape Cod to the Florida Keys. iYir-iru' 167. .17) .176 Risebrough K W., Hugged R. i . Gridin 1. J. and Goldberg i\. D. U%K) Pesticides: Transatlantic movements in the northeast trades, Science 15V. 12.1.1-1235. Rtsebrough R. W (1972) Personal communication. Seba D. B. and Corcoran L: F (1969) Surface slicks as concentrators of pesticides in the mat me environment Pest Worm. J. 3, 190 19.1. Seba D. B and Prospero J. M. (1971) Pesticides in (lie lower atmosphere of the northern equatorial Adamic Ocean. Atmospltem Environment 5, 1043-1050. MUMS 085738