RESUMEN
Reptiles, particularly snakes, could serve as bioindicators of contamination because some are comparatively long-lived, exhibit different trophic levels, and are at the top of their food chains. We test the null hypothesis that there are no differences in the concentrations of heavy metals in the blood, muscle and liver of water snakes (Nerodia spp.) from rivers in New Jersey, Tennessee and South Carolina. While the former site is in an urban/suburban area, the latter two sites are relatively rural and are located on Department of Energy sites. For the snakes from New Jersey, there were significant differences in metal concentrations among tissues for all metals, the highest levels for arsenic and selenium were in liver and kidney, for cadmium were in the liver, for chromium and lead were in skin, and for mercury and manganese were in the muscle. Body length was not correlated with metal levels, and there were more significant correlations for skin with internal tissues than for blood with other tissues. There were more significant correlations for mercury than for other metals. In comparing metal levels among states, levels were generally higher for snakes collected from South Carolina. These data indicate that, since water snakes accumulate contaminants differentially as a function of location, they can be useful bioindicators of environmental exposure to contaminants. Moreover, because of their wide geographical distribution and use of varying trophic compartments, this genus can be useful for cross-site comparisons.
Asunto(s)
Colubridae , Monitoreo del Ambiente , Hígado/metabolismo , Metales Pesados/análisis , Músculos/metabolismo , Selenio/análisis , Contaminantes Químicos del Agua/análisis , Animales , Colubridae/sangre , Colubridae/metabolismo , Metales Pesados/farmacocinética , New Jersey , Selenio/farmacocinética , South Carolina , Tennessee , Distribución Tisular , Contaminantes Químicos del Agua/farmacocinéticaRESUMEN
We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in a small species of fish (Central stonerollers, Campostoma anomalum) collected from East Fork Poplar Creek (EFPC) and a reference site in eastern Tennessee. Stonerollers are minnows in the Cyprinidae family that serve as prey for many carnivores in aquatic systems. Fish were collected from East Fork Poplar Creek within the U.S. Department of Energy's Y-12 National Security Complex, part of the Oak Ridge Reservation, and from a reference stretch of the Little River in East Tennessee. Whole fish were homogenized for analysis. Concentrations of all metals (except arsenic) were significantly higher in stonerollers from EFPC compared to the reference site. Mercury levels in minnows from EFPC averaged 0.4 ppm (microg/g), four times higher than the average for fish in the U.S. in general. This was higher than levels in fish from the nearby Clinch River and higher than fillets of white bass (Morone chrysops) from the same creek. Most metal levels were inversely related to size and weight of the stonerollers, perhaps due to growth dilution.
Asunto(s)
Arsénico/análisis , Cyprinidae , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Animales , Monitoreo del Ambiente/métodos , Ríos , TennesseeRESUMEN
Comparatively little is known about heavy metal levels in reptiles, particularly for lizards. Yet lizards often are common predators that could serve as bioindicators of contamination on a small spatial scale. This study examined the differences in metal concentrations of adult brown anoles (Anolis sagrei) for arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in six locations in southern Florida, USA, from Lake Okeechobee (Pahokee) south to Key West. We predicted that levels of contaminants would be higher in the industrialized ports (Port Everglades, Port of Miami) and at a landfill (in Key West) compared to a campground, tropical garden, and marine laboratory. Males were significantly larger than females, as expected. Although there were significant locational differences in metal concentrations, they did not fit a consistent pattern, either among sites or between reference and study sites. However, the lowest levels were generally found at Everglades Marina and Campground (except for selenium) and at Fairchild Tropical Garden (except for manganese). For females, size was significantly correlated with cadmium, lead, and mercury levels, while for males, there were significant correlations between length and arsenic, chromium, and manganese concentrations. Where there were gender differences in metal levels, females had significantly higher levels than males even though they were smaller. We attribute these gender differences to differences in diet due to microhabitat differences in foraging locations. Females spend more time feeding near the ground and males spend more time feeding on tree trunks and branches where they consume more flying insects. This is the first study that examines concentrations of metals in lizards in the United States, and suggests that nonnative lizards may be useful in toxicological studies.
Asunto(s)
Ambiente , Monitoreo del Ambiente , Lagartos/metabolismo , Metales Pesados/análisis , Análisis de Varianza , Animales , Pesos y Medidas Corporales , Conducta Alimentaria/fisiología , Femenino , Florida , Geografía , Lagartos/fisiología , Masculino , Factores SexualesRESUMEN
Risks to humans and other organisms from consuming fish have become a national concern in the USA. In this paper, we examine the concentrations of 137Cs, arsenic, beryllium, cadmium, lead, mercury, and selenium in three species of fish from two river reaches adjacent to the US Department of Energy's Oak Ridge Reservation in Tennessee. We were interested in whether there were species and locational differences in radiocesium and metal concentrations and whether concentrations were sufficiently high to pose a potential health risk to humans or other receptors. Striped bass (Morone saxatilis) were significantly larger than white bass (M. chrysops), and crappie (Pomoxis spp.) were the smallest fish. Lead was significantly lower in striped bass, mercury was significantly higher in striped bass, and selenium was significantly higher in white bass compared to the other species. There were no other species differences in contaminants. White bass, the only species that was sufficiently abundant for a comparison, had significantly higher concentrations of cadmium, lead, and selenium in fillets from the Clinch River and significantly higher concentrations of mercury in fillets from Poplar Creek. The low concentrations of most contaminants in fish from the Clinch River do not appear to present a risk to humans or other consumers, although mercury concentrations in striped bass ranged as high as 0.79 ppm, well above the 0.5-ppm action level for human consumption of some US states.
Asunto(s)
Radioisótopos de Cesio/farmacocinética , Metales Pesados/farmacocinética , Perciformes/metabolismo , Contaminantes Químicos del Agua/farmacocinética , Contaminantes Radiactivos del Agua/farmacocinética , Animales , Cadena Alimentaria , Humanos , Especificidad de la Especie , Estadísticas no Paramétricas , TennesseeRESUMEN
Reptiles, specifically lizards and snakes, usually are excluded from environmental contamination studies and ecological risk assessments. This brief summary of available lizard and snake environmental contaminant data is presented to assist in the development of priorities for lizard and snake ecotoxicology. Most contaminant studies were not conducted recently, list animals found dead or dying after pesticide application, report residue concentrations after pesticide exposure, compare contaminant concentrations in animals from different areas, compare residue concentrations found in different tissues and organs, or compare changes in concentrations over time. The biological significance of the contaminant concentrations is rarely studied. A few recent studies, especially those conducted on modern pesticides, link the contaminant effects with exposure concentrations. Nondestructive sampling techniques for determining organic and inorganic contaminant concentrations in lizards and snakes recently have been developed. Studies that relate exposure, concentration, and effects of all types of environmental contaminants on lizards and snakes are needed. Because most lizards eat insects, studies on the exposure, effects, and accumulation of insecticides in lizards, and their predators, should be a top priority. Because all snakes are upper-trophic-level carnivores, studies on the accumulation and effects of contaminants that are known to bioaccumulate or biomagnify up the food chain should be the top priority.