Environ. Sci. Technol. 2003, 37, 5496-5501
Temporal Trend Studies on Tetraand Pentabrominated Diphenyl Ethers and Hexabromocyclododecane in Guillemot Egg from the Baltic Sea ULLA SELLSTRO ¨ M , * ,† A N D E R S B I G N E R T , ‡ AMELIE KIERKEGAARD,† L I S B E T H H A¨ G G B E R G , † CYNTHIA A. DE WIT,† MATS OLSSON,‡ AND BO JANSSON† Laboratory for Analytical Environmental Chemistry, Institute of Applied Environmental Research, Stockholm University, SE-106 91 Stockholm, Sweden, and Contaminant Research Group, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
Guillemot eggs from the Baltic Sea, sampled between 1969 and 2001, were analyzed for tetra- and pentabromodiphenyl ethers (2,2′,4,4′-tetraBDE (BDE-47), 2,2′,4,4′,5pentaBDE (BDE-99), and 2,2′,4,4′,6-pentaBDE (BDE-100)), and hexabromocyclododecane (HBCD). This temporal trend study indicates that the concentrations of the polybrominated diphenyl ether compounds increased from the 1970s to the 1980s, peaking around the mid- to the late-1980s. These peaks are then followed by a rapid decrease in concentrations during the rest of the study period, with the concentrations of the major BDE congener below 100 ng/g lipid weight at the end of the period. This corresponds to less than 10% of its peak values. The concentrations of HBCD show a different pattern over time. After a peak in the middle of the 1970s followed by a decrease, the concentrations increased during the latter part of the 1980s. During the recent 10-yr period no significant change has occurred, and the annual mean concentrations are more or less stable at a higher level as compared to the beginning of the study period.
Introduction In 1981, tri- to hexabromodiphenyl ethers were found in fish from the Swedish River Viskan (1). Polybrominated diphenyl ethers (PBDEs) have since been found in environmental samples from marine, freshwater, and terrestrial environments as well as in humans as reviewed by de Wit (2). Hexabromocyclododecane (HBCD) has been found in sediments and fish from Japan and Sweden (3, 4) air and sewage sludge in Sweden (2, 5) and also recently in herring (6) and seal (7) from the Baltic Sea. Various products containing lower brominated BDEs as well as single congeners have been shown in experimental studies to produce effects in both fish and mammals. This includes liver enzyme induction, activation of the Ah receptor, * Corresponding author phone: +46 8 674 71 81; fax: +46 8 674 76 37; e-mail:
[email protected] † Stockholm University. ‡ Swedish Museum of Natural History. 5496
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ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 37, NO. 24, 2003
immunologic effects, neonatal neurotoxic effects, effects on thyroid hormone, and vitamin A levels (reviewed in refs 2 and 8). Very little is known about the toxicology of HBCD, but it has been found to cause an increase in recombination frequency in two mammalian in vitro intragenic recombination assays, indicating that it may induce cancer via a nonmutagenic mechanism (9), skin sensitization (10), and cause inhibition of plasma membrane uptake of the neurotransmitters dopamine, glutamate, and γ-amino-n-butyric acid (GABA) (11). Initial studies in juvenile rainbow trout indicate that HBCD may act as a peroxisome proliferator, which is also a mechanism implicated in nonmutagenic cancer (12). The use of flame retardants has increased due to stricter fire regulations in several countries and an increased use of plastic materials and synthetic fibers (overviewed in refs 2 and 13). Paralleling their increased usage, increasing tetraand pentaBDE concentrations were indicated in a laminated sediment core collected in the southern part of the Baltic Proper (14). A study of PBDE concentrations in pooled samples of guillemot (Uria algae) eggs in the Baltic Proper indicated a rapid increase during the late 1970s and early 1980s as did the concentrations in pike from a Swedish lake (15, 16). Both increasing and decreasing concentrations were indicated in Dutch rivers and the North Sea during the mid1980s to the early to mid-1990s (see ref 2 for a review). This was also the case in a later investigation (up to 1999) of sediment and fish from some locations in The Netherlands, the U.K., and Ireland (17). New results from other countries confirm, however, that the PBDE trends generally increase globally: sediment from Norway, trout from the Great Lakes (18, 19), ringed seal from the Canadian Arctic (20), and beluga from Baffin Island (21, 22). In herring gull eggs from the Great Lakes, the PBDE concentrations increased exponentially from 1981 to 2000 (23), and there are similar indications of exponential increases in human breast milk from North America (24, 25). In human breast milk from Swedish mothers, increasing tri- to hexaBDE concentrations were indicated in pooled samples collected between 1972 and 1997 (26). Over the last years this trend has stopped, and a decrease has been observed (27). The same maximum in the late 1990s has also been seen in human serum in Norway (28). To improve the understanding of the temporal trend of PBDE in the guillemot eggs from the Baltic Proper, the present study includes complementary retrospective analyses for years not studied in the first temporal trend (15) and, in addition, the most recent time period is included. For some years, the analyses were based on individual egg specimens instead of pooled samples in order to understand the variation in concentrations and thereby indicate the uncertainty in the pooled sample analysis. In these complementary analyses, HBCD was also determined. This is, to the best of our knowledge, the first temporal trend on HBCD.
Experimental Section Samples. Since the late 1960s, guillemot eggs have been collected annually for studies of temporal trends of various contaminants (29) and stored in the Swedish Environmental Specimen Bank (www.nrm.se/mg). The present temporal study is partly based on archived samples, but since 1992, the annual analysis of tetra- and pentaBDE has been part of the Swedish Environmental Monitoring Program. Guillemot eggs have previously been shown to be a very important matrix for studies of persistent environmental contaminants (30). Some ecological qualities of the species have been a prerequisite for the value of the species as a matrix in 10.1021/es0300766 CCC: $25.00
2003 American Chemical Society Published on Web 11/06/2003
TABLE 1. Concentrations of PBDE and HBCD in Guillemot Eggs (ng/g lipid weight)a year
p/m
BDE-47
BDE-99
BDE-100b
HBCD
% lipids
1969 1971 1972 1973 1975 1976 1976
p p p p p p m
1977 1978 1980 1981 1982 1983 1985 1986 1987 1988 1989
p p p p p p p p p p m
1990 1992 1992
p p m
1993
m
1994
m
1995
m
1996
m
1997
m
1998
m m
2000
m
2001
m
8.5 12 2.0 6.3 81 82 100 (46-220) 41 65 130 120 150 150 170 160 110 180 190 (110-320) 120 35 37 (20-66) 54 (21-280) 28 (8.9-50) 21 (9.1-51) 21 (5.6-110) 13 (7.4-22) 10 (
