Geckos as indicators of mining pollution.

Catastrophic collapse of a mine tailings dam released several million cubic meters of toxic mud and acidic water into the Guadiamar River valley, southern Spain, in 1998. Remediation efforts removed most of the sludge from the floodplain, but contamination persists. Clean-up activities also produced clouds of aerosolized materials that further contaminated the surrounding landscape.

Influence of larval period on responses of overwintering green frog (Rana clamitans) larvae exposed to contaminated sediments.

Pond-breeding amphibians exhibit large intra- and interspecific differences in the duration of the aquatic larval phase. In contaminated aquatic environments, a prolonged larval phase means prolonged exposure to pollutants and, potentially, more severe toxic effects. In the laboratory, we tested this hypothesis by exposing green frog larvae (Rana clamitans) to commercial clean sand (control), sediment from an abandoned surface mine (mine), or sediment contaminated with coal combustion waste (CCW).

Functional relationships among selenium concentrations in the diet, target tissues, and nondestructive tissue samples of two species of snakes.

Nondestructive sampling methods, such as removal of feathers for contaminant analysis, are desirable in ecological monitoring programs that seek to minimize the impacts of harvesting organisms. Although many reptiles are declining worldwide, nondestructive sampling techniques seldom have been employed for assessing contaminant exposure in these organisms. In this study, we examined the utility of nondestructive tissue sampling for assessing Se exposure in reptiles.

Transfer of selenium from prey to predators in a simulated terrestrial food chain.

Little is known about the accumulation and effects of selenium in reptiles. We developed a simplified laboratory food chain where we fed commercial feed laden with seleno-D,L-methionine (30 microg/g dry mass) to crickets (Acheta domestica) for 5-7 d. Se-enriched crickets (approximately 15 microg/g Se [dry mass]) were fed to juvenile male and female lizards (Sceloporus occidentalis) for 98 d while conspecifics were fed uncontaminated crickets.

Maternal transfer of selenium in Alligator mississippiensis nesting downstream from a coal-burning power plant.

Selenium (Se) is embryotoxic in many oviparous vertebrates, but little is known about maternal transfer of Se and its impact in reptiles. Over a four-year period, we collected three clutches of eggs of the American alligator (Alligator mississippiensis) from a single nest at a site contaminated with Se and compared egg and hatchling Se concentrations and clutch viability from this nest to nests downstream from the contaminated site (two clutches from two nests) and at a reference site (two clutches from two nests). Eggs and hatchlings from the nest at the Se-contaminated site and downstream nests had elevated Se concentrations (2.

Trophic and maternal transfer of selenium in brown house snakes (Lamprophis fuliginosus).

Excessive concentrations of dietary Se are toxic to oviparous vertebrates (i.e., fish and birds) but little is known about its accumulation and effects in reptiles.

Species-specific responses of developing anurans to coal combustion wastes.

Field surveys and field experiments have previously documented adverse effects of solid byproducts from coal incineration (coal combustion wastes (CCW)) on larval amphibians inhabiting aquatic habitats. However, a definitive link between CCW-exposure and developmental abnormalities has not been established because no studies have addressed the direct effects of prolonged exposure to CCW on larval amphibian development under controlled laboratory conditions. In the laboratory we exposed green frog (Rana clamitans) and wood frog (Rana sylvatica) larvae to either clean sand or CCW-contaminated sediment to investigate the direct effects of CCW exposure on trace element accumulation, growth, developmental rate, malformations, survival, and metamorphic success.