In Situ Behavioral Response of Common Loons Associated with Elevated Mercury (Hg) Exposure

Nocera, Joseph J.; Taylor, Philip D.

doi:10.5751/es-00066-020210

Cited by 67 publications

(52 citation statements)

References 25 publications

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“…Therefore, we selected a NEHC of 0.5 μg/g developed specifically to estimate mercury risk to bald eagles , which resulted in considerably lower estimates of risk to bald eagles at our sites; only nine sites had mercury concentrations >0.5 μg/g. However, there is evidence that piscivorous birds are being negatively affected by mercury in fish elsewhere (e.g., Scheuhammer and Blancher 1994;Scheuhammer et al 1998;Nocera and Taylor 1998). One might therefore argue that bald eagle populations would be increasing more rapidly if not for mercury, which would support the use of the lower TRVs.…”

Section: Dieldrin -Mink Dieldrin -Bald Eaglementioning

confidence: 99%

Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Hinck

Schmitt

Chojnacki

et al. 2008

Environ Monit Assess

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Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles were at greater risk to total DDT and total PCBs than mink, whereas risks of TCDD-EQ, mercury, and selenium were greater to mink than bald eagle.

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Section: Dieldrin -Mink Dieldrin -Bald Eaglementioning

confidence: 99%

Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Hinck

Schmitt

Chojnacki

et al. 2008

Environ Monit Assess

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show abstract

“…Aspergillosis has frequently been identified as a cause of death in loons (McIntyre, 1988), although in most cases it is presumed secondary to other conditions. Common loons nesting on acidified lakes (Evers et al, 1998) or feeding downstream of anthropogenic sources of mercury (Barr, 1986) may accumulate high levels of mercury in their tissues with possible reproductive repercussions at minimum (Barr, 1986;Nocera and Taylor, 1998). An interaction of mortality factors has been proposed to account for die-offs that occasionally occur in common loons wintering along the Atlantic and Gulf coasts of North America (Spitzer, 1995;Forrester et al, 1997;Augsperger et al, 1998).…”

mentioning

confidence: 99%

Necropsy Findings and Environmental Contaminants in Common Loons from New York

Stone

Okoniewski

2001

Journal of Wildlife Diseases

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Diagnostic and analytical findings are presented for 105 common loons (Gavia immer) found dead or debilitated in New York (USA) from 1972-99. Aspergillosis (23% of cases) and ingestion of lead fishing weights (21%) were the most common pathologies encountered. Stranding on land, shooting, other trauma, gill nets, air sacculitis and peritonitis, and emaciation of uncertain etiology accounted for most of the remaining causes of disease or death. Analysis for total mercury in the liver of 83 loons yielded a geometric mean (gm) of 10.3 mg/kg (wet basis) and range of 0.07 to 371 mg/ kg, with emaciated birds generally showing higher levels. Organochlorine contaminant levels in brain were generally low, principally consisting of PCB's (gm ϭ 2.02 mg/kg) and DDE (0.47 mg/kg).

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“…Although physiological impairment has been the most studied area of methylmercury toxicity in birds, behavioral anomalies may be more indicative of deleterious effects leading to declines in populations. Exposure to methylmercury has been shown to cause subtle behavioral changes in great egrets (Ardea albus) (Bouton et al 1999), common loons (Gavia immer) (Nocera and Taylor 1998), and three species of songbirds (Hallinger et al 2010). In the current study, young homing pigeons displayed signs of flight behavior impairment when exposed prenatally and continually after hatching.…”

Section: Discussionmentioning

confidence: 99%

“…5, No. 1;2016 biomagnify. Methylmercury is highly toxic and is the form that is most bioavailable; concentrating at the top of food webs potentially causing severe neurological damage (Wolfe et al 1998).…”

Section: Discussionmentioning

confidence: 99%

Effects of Parental and Direct Methylmercury Exposure on Flight Activity in Young Homing Pigeons (Columba livia)

Moye¹,

Perez²,

Pritsos³

2016

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Mercury is one of the most common metals found in contaminated ecosystems. It occurs naturally, but high levels found in contaminated areas derive from human use practices. Among the most vulnerable species to exposure are birds that live, nest, or feed in or near these contaminated ecosystems. Because of the known neurological effects of mercury on birds, it is hypothesized that effects upon migratory ability would be evident after exposure to low levels of this metal, and effects may be exacerbated in young birds. Difficulties in following mercury exposed birds once they migrate away from contaminated areas have left investigators with insufficient data to establish exposure levels causing injury of migratory species due to migration disruption. Breeding pigeons were exposed to ~1.0 mg/kg/day methylmercury via the drinking water, and first round offspring were trained to home after fledging, while also continually exposed to methylmercury. The young pigeons were released individually for three flights, and flight times were assessed and compared to control young pigeon flight times from 3.5, 9, 21, 53, 65, and 98 air miles as well as two individual flights at ~50 air miles from multiple directions. Results indicate that methylmercury exposed birds exhibit slower flight times than controls during the initial flight, and generally improve on successive flights at each distance and direction. This may suggest orientation impairment and allude to migration disruption in migratory species.

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In Situ Behavioral Response of Common Loons Associated with Elevated Mercury (Hg) Exposure

Cited by 67 publications

References 25 publications

Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Necropsy Findings and Environmental Contaminants in Common Loons from New York

Effects of Parental and Direct Methylmercury Exposure on Flight Activity in Young Homing Pigeons (Columba livia)

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