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Title: Mercury levels in Great Lakes herring gull eggs, 1972--1992

Abstract

Since 1971, the herring gull (Larus argentatus) has been used as a sentinel species for monitoring the levels of persistent contaminants in the Great Lakes ecosystem. In this study, 21 herring gull colonies in the Great Lakes and connecting channels were sampled for years 1972--1976, 1981--1983, 1985 and 1992. For each year, 10 eggs (usually) were collected from each colony site and analyzed for total mercury (ppm, wet weight). Results indicated that eggs from Lake Ontario displayed the highest mercury levels, mean = 0.28 (s.d. = 0.08) to 0.73 (0.23). Lake Erie typically displayed the lowest egg mercury levels, 0.18 (0.08) to 0.24 (0.11). Overall, mercury levels ranged from 0.12 (0.02) in 1985 to 0.88 (0.23) in 1982 for Channel-Shelter Island (Lake Huron) and Pigeon Island (Lake Ontario), respectively. Generally, all colony sites showed peak mercury levels in 1982. A significant decline in egg mercury levels was observed in six colony sites between 1972 and 1992 and in three colony sites between 1981 and 1992. The mean herring gull egg mercury levels observed in the early and mid 1970s and in 1982 for some colony sites were within the range found which potentially reduces hatchability in other fish-eating bird species.

Authors:
; ; ;  [1]
  1. Canadian Wildlife Service, Burlington, Ontario (Canada). Canada Centre for Inland Waters
Publication Date:
OSTI Identifier:
218475
Report Number(s):
CONF-9511137-
ISBN 1-880611-03-1; TRN: IM9619%%196
Resource Type:
Conference
Resource Relation:
Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 56 BIOLOGY AND MEDICINE, APPLIED STUDIES; GREAT LAKES; WATER POLLUTION; BIOLOGICAL INDICATORS; BIRDS; BIOLOGICAL STRESS; MERCURY; BIOLOGICAL ACCUMULATION; AQUATIC ECOSYSTEMS; GEOGRAPHICAL VARIATIONS

Citation Formats

Weseloh, D.V., Koster, M.D., Ryckman, D.P., and Struger, J.. Mercury levels in Great Lakes herring gull eggs, 1972--1992. United States: N. p., 1995. Web.
Weseloh, D.V., Koster, M.D., Ryckman, D.P., & Struger, J.. Mercury levels in Great Lakes herring gull eggs, 1972--1992. United States.
Weseloh, D.V., Koster, M.D., Ryckman, D.P., and Struger, J.. Sun . "Mercury levels in Great Lakes herring gull eggs, 1972--1992". United States. doi:.
@article{osti_218475,
title = {Mercury levels in Great Lakes herring gull eggs, 1972--1992},
author = {Weseloh, D.V. and Koster, M.D. and Ryckman, D.P. and Struger, J.},
abstractNote = {Since 1971, the herring gull (Larus argentatus) has been used as a sentinel species for monitoring the levels of persistent contaminants in the Great Lakes ecosystem. In this study, 21 herring gull colonies in the Great Lakes and connecting channels were sampled for years 1972--1976, 1981--1983, 1985 and 1992. For each year, 10 eggs (usually) were collected from each colony site and analyzed for total mercury (ppm, wet weight). Results indicated that eggs from Lake Ontario displayed the highest mercury levels, mean = 0.28 (s.d. = 0.08) to 0.73 (0.23). Lake Erie typically displayed the lowest egg mercury levels, 0.18 (0.08) to 0.24 (0.11). Overall, mercury levels ranged from 0.12 (0.02) in 1985 to 0.88 (0.23) in 1982 for Channel-Shelter Island (Lake Huron) and Pigeon Island (Lake Ontario), respectively. Generally, all colony sites showed peak mercury levels in 1982. A significant decline in egg mercury levels was observed in six colony sites between 1972 and 1992 and in three colony sites between 1981 and 1992. The mean herring gull egg mercury levels observed in the early and mid 1970s and in 1982 for some colony sites were within the range found which potentially reduces hatchability in other fish-eating bird species.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Dec 31 00:00:00 EST 1995},
month = {Sun Dec 31 00:00:00 EST 1995}
}

Conference:
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  • The levels of 14 organochlorine contaminants in herring gull (Larus argentatus) eggs were measured at up to 13 Great Lakes colonies during the period of 1974--1993. Linear regression was applied to all transformed contaminant values at each site to establish statistical patterns. Long term analysis (1974--1993) consisted of finding an appropriate change point model, comparing its efficacy with a single line model and choosing the most appropriate. Fifty-eight percent of the analyses required a change point in the model, the most common change points were 1987 and 1991. Of the 169 total analyses, 63% showed a significant decrease, 6% showedmore » a significant increase and 31% showed no significant pattern over time, i.e. slope did not differ from zero. Increasing contaminant concentrations for at least one compound were found in Lakes Huron, Michigan, Ontario and Superior. In a second temporal analysis, recent trends for SUM PCB and DDE were assessed by single line regression over three time periods: 1983--1993, 1989--1993 and 1990--1993. In 89% of the analyses (n = 78), levels showed no statistical change, 5% showed a decrease and 6% showed a significant increase. Rising levels were round in Lake Huron and Superior; decreasing levels were found in the Niagara and Detroit Rivers and Lake Erie. Spatial analysis on data from the last five years indicated that oxychlordane, dieldrin and heptachlor epoxide had their greatest concentrations at Lake Michigan sites; DDE and SUM PCBs were greatest at Saginaw Bay, Lake Huron and mirex was most elevated in Lake Ontario.« less
  • Short-term changes in hydrophobic organic chemical concentrations in gull eggs are synchronized within and across the Great Lakes. Deviations from long-term trends for PCBs, DDE, dieldrin, mirex, and hexachlorobenzene in Lake Superior gull eggs correlate with deviations of those chemicals in gull eggs from Lake Ontario and, to a lesser extent, the other Great Lakes. This synchrony is inconsistent with the hypothesis that changes in tissue levels are controlled by changes in external loading. Rather, the synchrony implies that some overriding factor -- probably weather -- concurrently affects internal recycling of chemicals across chemicals across the Great Lakes. From 1980more » to 1992, deviations from long-term weather patterns correlated significantly with deviations of some hydrophobic chemicals. A weather-driven hypothesis implies that (1) apparent changes in the rate of chemical decline result from uncontrollable changes in internal recycling as opposed to potentially controllable inputs from external sources and (2) the current period of slow contaminant decline is likely to be a short-term phenomenon.« less
  • The author evaluated the fit of 3 alternative models to herring gull (Larus argentatus) egg PCB concentration data from 1978--1992 to examine whether PCB levels were decreasing or had ceased to decline. The best fit models indicate that, following initial declines, no discernible PCB decreases are occurring in 4 of the 5 lakes. Only Lake Erie indicates a continued PCB decline, though the Erie data may be too noisy to differentiate model fits. These results are consistent with previous analyses indicating stable PCB concentrations in Lake Michigan fishes and suggest that further improvements may be too slow to be ofmore » practical importance from a management perspective.« less
  • The Canadian Wildlife Service`s herring gull (Larus argentatus) surveillance program has demonstrated the utility of this species as a monitor of spatial and temporal trends in Great Lakes contaminant levels. Organochlorine concentrations in herring gull eggs decreased significantly in the 1970s and early 1980s as a result of control measures. Since the mid-1980s, however, concentrations of many compounds have been relatively constant. In addition, periodic fluctuations in egg contaminant concentrations hamper the ability to interpret more recent temporal trends in organochlorine levels. To evaluate the progress towards achieving the virtual elimination of organochlorines from the Great Lakes the authors mustmore » improve their understanding of the factors which regulate organochlorine bioaccumulation. This is particularly important for those species which have been selected as key indicators of ecosystem contamination, such as the herring gull. The goal of this paper is to examine some of the factors which may be responsible for the temporal fluctuations in herring gull egg contaminant concentrations. The regulation of contaminant bioavailability and transfer by changes in weather patterns and food web dynamics will be examined.« less
  • Herring-gull (Larus argentatus) eggs were collected from five locations on the Great Lakes and from one colony on the Atlantic coast for organochlorine analysis and mutagenesis testing. The Great Lakes colonies were chosen for their different contaminant levels, while the Atlantic coast colony was used as a relatively clean control. The eggs were homogenized and extracted, and the extracts were tested in the Salmonella/mammalian microsome assay for induction of point mutations and in Chinese hamster ovary (CHO) cells for the induction of sister chromatid exchanges (SCEs) and chromosome aberrations. None of the extracts was mutagenic in Salmonella, either in themore » presence of absence of metabolic activation. However, all of the extracts, including the clean control, caused significant increases in both the SCE rate and in the number of chromosome aberrations in the CHO cells. There was no apparent relationship between contaminant levels and the magnitude of these responses or the doses at which they occurred, although the chemical analysis indicated a wide range in the concentrations of the different organochlorides present.« less