Research Perfluorooctane Sulfonate in Fish-Eating Water Birds Including Bald Eagles and Albatrosses K U R U N T H A C H A L A M K A N N A N , * ,† J. CHRISTIAN FRANSON,‡ WILLIAM W. BOWERMAN,§ KRIS J. HANSEN,| PAUL D. JONES,† AND JOHN P. GIESY† National Food Safety and Toxicology Center, Department of Zoology, Institute of Environmental Toxicology, Michigan State University, East Lansing, Michigan 48824, U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison, Wisconsin 53711-6223, Department of Environmental Toxicology, Clemson University, 509 Westinghouse Road, P.O. Box 709, Pendleton, South Carolina 29670-0709, and 3M Environmental Laboratory, 935 Bush Avenue, St. Paul, Minnesota 55133
Perfluorooctane sulfonate (PFOS) was measured in 161 samples of liver, kidney, blood, or egg yolk from 21 species of fish-eating water birds collected in the United States including albatrosses from Sand Island, Midway Atoll, in the central North Pacific Ocean. Concentrations of PFOS in the blood plasma of bald eagles collected from the midwestern United States ranged from 13 to 2220 ng/mL (mean: 330 ng/ mL), except one sample that did not contain quantifiable concentrations of PFOS. Concentrations of PFOS were greater in blood plasma than in whole blood. Among 82 livers from various species of birds from inland or coastal U.S. locations, Brandt’s cormorant from San Diego, CA, contained the greatest concentration of PFOS (1780 ng/g, wet wt). PFOS was also found in the sera of albatrosses from the central North Pacific Ocean at concentrations ranging from 3 to 34 ng/mL. Occurrence of PFOS in birds from remote marine locations suggests widespread distribution of PFOS and related fluorochemicals in the environment.
Introduction Sulfonated perfluorochemicals are produced by an electrochemical fluorination process that results in a complex and variable mixture of chemicals in which fluorine atoms replace hydrogen atoms on the organic feedstock and rearrangement of carbon-carbon bonds (1). Because of the strength of the carbon-fluorine bond, the compounds created are environmentally stable. Fluorinated organic chemicals can repel both water (hydrophobic) and oils (oleophobic), reduce surface tension, act as catalysts for oligomerization and polymerization, and function under extreme conditions (1). The identification and quantification of sulfonated perfluorochemicals pose difficult analytical challenges. Reliable * Corresponding author telephone: (517)432-6321; fax: (517)4322310; e-mail:
[email protected]. † Michigan State University. ‡ U.S. Geological Survey. § Clemson University. | 3M Environmental Laboratory. 10.1021/es001935i CCC: $20.00 Published on Web 06/20/2001
2001 American Chemical Society
methods for extraction, separation, and identification of sulfornated perfluorochemicals in tissues and environmental media have been developed only recently (3), which allowed the detection of perfluorooctane sulfonate (PFOS) in sera of nonoccupationally exposed humans and in tissues of marine mammals and birds (3-5). Because of its potential for persistence and bioaccumulation, there is a concern regarding environmental distribution and fate of PFOS (6). Structurally similar perfluorinated compounds have been shown to affect cell-cell communication, membrane transport, and process of energy generation and peroxisome proliferation in laboratory animals (7, 8). Biomonitoring studies are useful to understand the distribution and concentrations of PFOS in biota. In this study, concentrations of PFOS were determined in samples of liver, kidney, egg yolk, whole blood, blood plasma, or sera of 21 species of fish-eating water birds collected across the United States. The aim of this study was to determine concentrations of PFOS in bird tissues. Liver, kidney, and sera of Laysan and black-footed albatrosses from the Sand Island, Midway Atoll, central North Pacific Ocean, were also analyzed to examine the presence of PFOS in more remote marine locations.
Materials and Methods Samples. A total of 161 samples comprised of 82 liver, 39 blood plasma, 15 sera, 10 whole blood, 8 kidney, and 7 egg yolk collected from 21 species of water birds was analyzed. The species analyzed include the following: double-crested cormorant (Phalacrocorax auritus), herring gull (Larus argentatus), ring-billed gull (Larus delawarensis), bald eagle (Haliaeetus leucocephalus), common loon (Gavia immer), brown pelican (Pelecanus occidentalis), white pelican (Pelecanus erythrorhynchos), great egret (Ardea alba), snowy egret (Egretta thula), wood stork (Mycteria americana), white-faced ibis (Plegadus chihi), black-crowned night heron (Nycticorax nycticorax), Franklin’s gull (Larus pipixcan), northern gannet (Sula bassanus), great black-backed gull (Larus marinus), osprey (Pandion haliaetus), red-throated loon (Gavia stellata), Brandt’s cormorant (Phalacrocorax penicillatus), great blue heron (Ardea herodias), Laysan albatross (Diomedea immutabilis), and black-footed albatross (Diomedea nigripes). All these species feed primarily on fish and shellfish except Franklin’s gull, which feeds heavily on insects. Birds were from several locations across the United States including Sand Island, Midway Atoll, in central North Pacific Ocean (Figure 1). For the purpose of discussion, results were grouped into three major classes: Great Lakes region, other U.S. locations (locations other than the Great Lakes region), and Midway Atoll. Tissues of birds from the midwestern United States including the Great Lakes were collected as a part of earlier monitoring studies for organochlorine pollutants in birds. Double-crested cormorants, herring gulls, ring-billed gulls, and bald eagle tissues were collected from several colonies in Michigan waters of the Great Lakes. All samples were collected between 1990 and 1998. Details regarding sampling location and sampling date are given in Tables 1 and 2. Age and sex of individuals were recorded when available. Blood plasma was collected primarily from nestlings. Blood samples of bald eagles were collected from nestling eagles from Michigan, Wisconsin, Minnesota, and Ohio. Samples were collected from nestlings by venipuncture of the brachialis vein using a 10-mL syringe. Plasma samples were prepared VOL. 35, NO. 15, 2001 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 1. Map of the United States showing sampling locations of birds analyzed in this study. by centrifugation within 12 h of collection and were frozen at -20 °C until analysis. Most of the liver samples for this study were acquired during an investigation of lead exposure in water birds caused by the ingestion of lead fishing sinkers (9). Liver tissue came primarily from birds that died at rehabilitation centers and wildlife shelters or from carcasses found on wildlife refuges in the continental United States. Liver samples were collected from the carcasses, wrapped in clean aluminum foil, and stored frozen at -20 °C until analysis. Liver and blood plasma of albatrosses were collected from adult male Laysan and black-footed albatrosses (g11 years old) on Sand Island, Midway Atoll, in the central North Pacific Ocean (28°11′ N, 177°22′ W) during 1993-1995. Blood was drawn from the brachial vein of each bird and placed in Vacutainers (Becton Dickinson vacutainer systems, Rutherford, NJ) containing 0.015 mL of ethylenediaminetetraacetic acid (EDTA) anticoagulant and centrifuged, and the plasma was harvested and stored at -20 °C until analysis. Analysis. Concentrations of PFOS in tissues were determined by use of high-performance liquid chromatography (HPLC) coupled with electrospray tandem mass spectrometry (3). The internal standard, 1H,1H,2H,2H-perfluorooctane sulfonate, was purchased from ICN (Costa Mesa, CA). The PFOS standard was 86.4% pure. Reported concentrations were corrected for purity of the PFOS standard. One milliliter of sera, 500 ng of internal standard, 1 mL of 0.5 M tetrabutylammonium hydrogen sulfate solution (adjusted to pH 10), and 2 mL of 0.25 M sodium carbonate buffer were added to a 15-mL polypropylene tube for extraction. After being thoroughly mixed, 5 mL of methyl tert-butyl ether (MTBE) was added to the solution, and the mixture was shaken for 20 min. The organic and aqueous layers were separated by centrifugation, and an exact volume of MTBE (4 mL) was removed from the solution. The aqueous mixture was rinsed with MTBE and separated twice; all rinses were combined in a second polypropylene tube. The solvent was allowed to evaporate under nitrogen before being reconstituted in 0.5-1 mL of methanol. The sample was vortexed for 30 s and passed through a 0.2-µm nylon filter into an autosampler vial. For the extraction of liver samples, a liver 3066
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homogenate of 1 g of liver to 5 mL of Milli-Q water was prepared. One milliliter of the homogenate was added to a polypropylene tube, and the sample was extracted according to the procedure described above. Analyte separation was performed using a HewlettPackard HP1100 liquid chromatograph modified with low dead-volume internal tubing. A total of 10 µL of extract was injected onto a 50 × 2 mm (5 µm) Keystone Betasil C18 column with a 2 mM ammonium acetate/methanol mobile phase starting at 10% methanol. At a flow rate of 300 µL/min, the gradient increased to 100% methanol at 11.5 min before reverting to original conditions at 13 min. Column temperature was maintained at 25 °C. Although PFOS eluted at about 7.5 min, the longer chromatographic run was necessary to completely elute all extractables from the column. For quantitative determination, the HPLC system was interfaced to a Micromass (Beverly, MA) Quattro II atmospheric pressure ionization tandem mass spectrometer operated in the electrospray negative mode. Instrumental parameters were optimized to transmit the [M - K]- ion. When possible, multiple daughter ions were monitored, but quantitation was based on a single product ion. For all analyses, the capillary was held between 1.6 and 3.2 kV. In the electrospray tandem mass spectrometry (ESMSMS) system, the 499 Da f 80 Da transition can provide a stronger signal than the 499 Da f 99 Da transition of the PFOS analysis. However, in the analysis of tissue samples collected from some species of birds, an unidentified interferent was present in the 499 Da f 80 Da transition. Although this interferent was rarely observed, to ensure complete selectivity, quantitation was based on the 499 Da f 99 Da transition. The presence of PFOS was verified by quantitative agreement ((30%) between two or more product ions. Because of the variety of matrixes analyzed (with respect to both species and tissues) and because of evolving analytical methods, the limit of quantitation (LOQ) was variable. For the estimation of the LOQ, the tissue (including plasma) samples were compared to an unextracted standard calibration curve. Concentrations in samples that were greater than the “lowest acceptable standard” were considered to be valid. A curve point was deemed acceptable if (i) it was back-
TABLE 1. Concentrations (Mean) of PFOS in Tissues of Water Birds from the Great Lakes Regiona location Gull Is., Geo Bay Hyrn Island, Lake Superior Little Charity Is., Lake Huron Otter Island, Lake Superior Scar Crow Is., Thunder Bay St. Matrin Is., Great Lakes Little Charity Is., Lake Huron
date Double Crested Cormorant Blood (Michigan) Jul 18, 1991 Jul 29, 1991 Jul 25, 1991 Jul 29, 1991 Jul 4, 1991 Jul 13, 1991 Herring Gull Blood (Michigan) Jul 29, 1991
PFOS 78 36 164-188 (176) 34 132 124-243 (184)
remarks
N)2 N)2
57-68 (63)
N)2
Huron Is., Lake Superior Little Charity Is., Lake Huron
Double Crested Cormorant Plasma (Michigan) Jul 29, 1991 Jul 25, 1991
63-95 (79) 209-372 (291)
N)2 N)2
Little Charity Is., Lake Huron
Herring Gull Plasma (Michigan) Jul 29, 1991
239-391 (315)
N)2
Sulphur Is., Thunder Bay, Lake Huron
Ring-Billed Gull Egg Yolk (Michigan) Jun 9, 1995
30-126 (67)
N)3
Lake Winnipegosis, Manitoba, Canada
Double Crested Cormorant Egg Yolk Jun 14, 1995
21-220 (157)
N)4
388 273 160 144 35 13 105 75 2220 2030 29 79 188 145 141 71 21 49
