Toxic exposure of songbirds to lead in the Southeast Missouri Lead Mining District.

Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000-3,200 mg Pb/kg. Analyses of earthworms [33-4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms.

Toxic effects of dietary methylmercury on immune system development in nestling American kestrels (Falco sparverius).

This study evaluated the effects of dietary methylmercury (MeHg) on immune system development in captive-reared nestling American kestrels (Falco sparverius) to determine whether T cell-mediated and antibody-mediated adaptive immunity are targets for MeHg toxicity at environmentally relevant concentrations. Nestlings received various diets, including 0 (control), 0.6, and 3.

Toxic effects of dietary methylmercury on immune function and hematology in American kestrels (Falco sparverius).

Fifty-nine adult male American kestrels (Falco sparverius) were assigned to one of three diet formulations including 0 (control), 0.6, and 3.9 µg/g (dry wt) methylmercury (MeHg).

Mercury in the blood and eggs of American kestrels fed methylmercury chloride.

American kestrels (Falco sparverius) were fed diets containing methylmercury chloride (MeHg) at 0, 0.6, 1.7, 2.

A physiologically based toxicokinetic model for methylmercury in female American kestrels.

A physiologically based toxicokinetic (PBTK) model was developed to describe the uptake, distribution, and elimination of methylmercury (CH(3)Hg) in female American kestrels. The model consists of six tissue compartments corresponding to the brain, liver, kidney, gut, red blood cells, and remaining carcass. Additional compartments describe the elimination of CH(3)Hg to eggs and growing feathers.

Dietary toxicity and tissue accumulation of methylmercury in American kestrels.

American kestrels (Falco sparverius) were fed meat diets containing 0, 3, 6, or 12 ppm (dry weight) methylmercury chloride. Birds fed the 12-ppm diet started to show signs of neurotoxicity after 26 days and all died in 39-49 days. One male kestrel fed the 6-ppm diet died after 75 days of exposure and several others showed signs of neurotoxicity after 45 days.

Effects of methylmercury on reproduction in American kestrels.

Sixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.

Blarina brevicauda as a biological monitor of polychlorinated biphenyls: evaluation of hepatic cytochrome P450 induction.

We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with beta-naphthoflavone (betaNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received betaNF but not in shrews that received PB; PROD was not induced by either exposure.

Establishing appropriate measures for monitoring aging in birds: comparing short and long lived species.

In order to reveal patterns of reproductive aging in birds we focus on a short lived species, the Japanese quail and the American kestrel, which has a life span of medium length. Quail have been studied extensively in the laboratory as models for understanding avian endocrinology and behavior, and as a subject for toxicological research and testing. In the lab, Japanese quail show age-related deterioration in endocrine, behavioral, and sensory system responses; the American kestrel is relatively long lived and shows moderate evidence of senescence in the oldest birds.

The effects of polychlorinated biphenyls (Aroclor 1242) on thyroxine, estradiol, molt, and plumage characteristics in the American kestrel (Falco sparverius).

The purpose of this experiment was to determine the effects of Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), on plumage characteristics and molt in the American kestrel, Falco sparverius. Several characteristics of plumage, including color and molt schedule, are modulated by hormonal signals and hence may be modified by endocrine-active contaminants. If so, the functions of plumage (e.

Immunological and physiological effects of chronic exposure of Peromyscus leucopus to Aroclor 1254 at a concentration similar to that found at contaminated sites.

Polychlorinated biphenyls (PCBs) are environmental contaminants known to cause adverse health effects to biological systems. Limited data are available on their effects on the immune system of wildlife species. Previously, we found that 4 and 6-week-old white-footed mice (Peromyscus leucopus) born from dams injected with a single dose (300 mg/kg) of Aroclor 1254, had altered immunological, hematological, and biochemical responses.