Mirex and its degradation products in Great Lakes herring gulls

Abstract

Nitrated extracts of herring gull eggs from seven Lake Ontario colonies in 1977 were analyzed by glass capillary gas chromatography/mass spectrometry. Five minor mirex-related compounds were found in addition to mirex and the previously identified 8-monohydromirex (photomirex). The levels (milligrams/kilogram wet weight ± standard deviation) of all seven compounds were determined by high-resolution gas chromatography: 2,8-dihydromirex (0.016 ± 0.005); C10CI10H2 (II), possibly 3,8-dihydromirex (0.011 ± 0.003); 8monohydromirex (0.95 ± 0.14); CioClnH (III), possibly 9monohydromirex (0.077 ± 0.019); 10-monohydromirex (0.199 ± 0.025); mirex (2.58 ± 0.40); and C10CI12 (II) consistent with an isomer of mirex (0.039 ± 0.011). It was concluded that photodegradation was the only feasible mechanism for formation of these compounds, but that mirex and its photoproducts rapidly became sequestered in the ecosystem and protected from further degradation.

Concentrations and spatial patterns of organic contaminants in tree swallow (Tachycineta bicolor) eggs at United States and binational Great Lakes Areas of Concern, 2010–2015

“…Other industrial rivers (Genesee River, Turning Point Park = 18.8 ng/g; Rouge River AOC = 14.5 ng/g; River Raisin AOC = 14.0 ng/g; St. Clair River AOC = 13.8 ng/g; and Cuyahoga River AOC = 13.3 ng/g) also had mirex concentrations above background, as did some in‐basin non‐AOC sites, such as Cape Vincent (13.3 ng/g) and Chaumont River (11.2 ng/g), both near the intersection of Lake Ontario and the St. Lawrence River. The sites and AOCs on Lake Ontario, however, were not necessarily significantly more contaminated than the rest of the study locations in the present study as might have been postulated from the high exposure documented in fish, sediments , and birds in earlier decades. Current exposure in tree swallows, with a maximum value of 82.2 ng/g at the Rouge River AOC, was far below the average concentrations (2580 ng/g wet wt) in herring gulls from 7 sites across the Great Lakes in 1977 , when mirex was still being used.…”

“…The sites and AOCs on Lake Ontario, however, were not necessarily significantly more contaminated than the rest of the study locations in the present study as might have been postulated from the high exposure documented in fish, sediments , and birds in earlier decades. Current exposure in tree swallows, with a maximum value of 82.2 ng/g at the Rouge River AOC, was far below the average concentrations (2580 ng/g wet wt) in herring gulls from 7 sites across the Great Lakes in 1977 , when mirex was still being used. Mirex has been declining in herring gull eggs since it was banned .…”

Nontargeted Screening of Halogenated Organic Compounds in Bottlenose Dolphins (Tursiops truncatus) from Rio de Janeiro, Brazil

“…The other compound containing 11 chlorines (C 10 HCl 11 ) was identified as photomirex and confirmed by authentic standard (p. 22). Photomirex was previously reported as a mirex metabolite 31–34 . Dechlorane 602 (Dec 602) was also identified and confirmed by authentic standard (p. 25).…”

Winter Severity Affects Migration and Contaminant Accumulation in Northern Great Lakes Herring Gulls

“…In general, PCB contamination is more widespread in the southern portions of the Great Lakes, and this is reflected in greater PCB concentrations in abiotic and biotic compartments (Thomas and Frank 1983, Swackhammer and Armstrong 1987, Suns et al 1993, DeVault et al 1996. Mirex concentrations are greatest in samples from Lake Ontario and reflect historic point source inputs (Holdrinet et al 1978, Norstrom et al 1980). Notes: These adjusted concentrations were the residuals calculated after fitting a single exponential model with a nonzero asymptote to the log 10 -transformed egg concentrations.…”

“…Emphasis is placed upon the polychlorinated biphenyls (PCBs) because of their toxicological significance and on mirex for its utility as a geographic marker. Mirex concentrations are much greater in Lake Ontario than in the other Great Lakes because of two historic point sources in the Niagara and Oswego Rivers (Holdrinet et al 1978) and mirex concentrations in Lake Ontario Herring Gull eggs are much greater than in eggs from the other Great Lakes (Norstrom et al 1980). Increased mirex concentrations in Herring Gull eggs from northern Great Lakes colonies may reflect increased utilization of Lake Ontario during the overwintering period.…”