Maternal Transfer of Contaminants and Reduced Reproductive Success of Southern Toads (Bufo [Anaxyrus] terrestris) Exposed to Coal Combustion Waste

Abstract

Bioaccumulation of contaminants and subsequent maternal transfer to offspring are important factors that affect the reproductive success of wildlife. However, maternal transfer of contaminants has rarely been investigated in amphibians. We examined maternal transfer of trace elements in southern toads ( Bufo[Anaxyrus] terrestris) residing in two locations: (1) an active coal combustion waste (CCW) disposal basin and adjacent 40-ha floodplain contaminated with CCW over 35 years ago and (2) an uncontaminated reference site. Our study is among the few to document tissue concentration-dependent maternal transfer of contaminants and associated adverse effects in amphibians. We found that females collected from the CCW-contaminated area had elevated concentrations of Ni, Se, and Sr; these females also transferred elevated levels of Cu, Pb, Se, and Sr to their eggs compared to females from the reference site. Overall reproductive success, estimated as a function of clutch size and offspring viability, was reduced by 27% in clutches collected from parents from the contaminated site compared to the reference site. Offspring viability negatively correlated with female and/or egg concentrations of Se and Ni. Reproductive success negatively correlated with Se and Cu concentrations in females, and Se concentrations in eggs. Our study highlights how exposure to CCW can negatively affect amphibian reproduction.

Integrating copper toxicity and climate change to understand extinction risk to two species of pond‐breeding anurans

“…, , Metts et al. ). Because of their ubiquity and occurrence in contaminated habitats, these species represent excellent models for investigation into long‐term population‐level effects of Cu contamination.…”

Effects of metal and predator stressors in larval southern toads (Anaxyrus terrestris)

“…Ultimately we cannot attribute our observed effects to differential contamination history between wetlands because we had no replication of the two wetland types (reference vs. contaminated). However, previous amphibian studies conducted on populations from D-Area wetlands have documented 1) elevated body burdens of a suite of metals in adults, and 2) maternal transfer of metals to embryos, which correlated with reduced embryonic and larval viability (Hopkins et al 2006, Metts et al 2013). Although we did not measure maternal transfer, our data are consistent with other studies that have found negative effects of maternal transfer of heavy metals on offspring size and increased time to complete metamorphosis ).…”

Reproduction and hatchling performance in freshwater turtles associated with a remediated coal fly-ash spill

“…Among elements associated with coal fly ash, Hg and Se are of particular concern because they are known to cause negative reproductive effects in oviparous wildlife (e.g., Coyle et al, 1993;Skorupa, 1998;Janz et al, 2010;B.C. Hopkins et al, 2013a;Metts et al, 2013). Our results suggest that the 2008 coal fly-ash spill affected concentrations of these elements in turtle tissues (Table 1), but accumulation resulted in concentrations below those needed to elicit adverse effects at the time we conducted our study multiple years after remediation.…”