Assessment of a New Approach Method for Grouped Chemical Hazard Estimation: The Toxicity-Normalized Species Sensitivity Distribution (SSDn).

New approach methods are being developed to address the challenges of reducing animal testing and assessing risks to the diversity of species in aquatic environments for the multitude of chemicals with minimal toxicity data. The toxicity-normalized species sensitivity distribution (SSDn) approach is a novel method for developing compound-specific hazard concentrations using data for toxicologically similar chemicals. This approach first develops an SSDn composed of acute toxicity values for multiple related chemicals that have been normalized by the sensitivity of a common species tested with each compound.

Potential for Interspecies Toxicity Estimation in Soil Invertebrates.

Interspecies correlation estimation (ICE) models are linear regressions that predict toxicity to a species with few data using a known toxicity value in a surrogate species. ICE models are well established for estimating toxicity to fish and aquatic invertebrates but have not been generally developed or applied to soil organisms. To facilitate the development of ICE models for soil invertebrates, a database of single chemical toxicity values was compiled from knowledgebases and reports that included 853 records encompassing 192 chemicals and 12 species.

The physiological stress response of the Atlantic stingray (Hypanus sabinus) to aerial exposure.

Although secondary stress physiology of elasmobranchs is fairly well studied, gaps remain in our understanding of species differences, including stress recovery. We examined the physiological stress response to air exposure in Atlantic stingrays (Hypanus sabinus) using a serial sampling method requiring minimal handling. Many elasmobranch stress studies exclusively quantify glucose, although there is evidence that elasmobranchs are unusually reliant on ketone bodies.

Na⁺/K⁺-ATPase α1 mRNA expression in the gill and rectal gland of the Atlantic stingray, Dasyatis sabina, following acclimation to increased salinity.

Background: The salt-secreting rectal gland plays a major role in elasmobranch osmoregulation, facilitating ion balance in hyperosmotic environments in a manner analogous to the teleost gill. Several studies have examined the central role of the sodium pump Na(+)/K(+)-ATPase in osmoregulatory tissues of euryhaline elasmobranch species, including regulation of Na(+)/K(+)-ATPase activity and abundance in response to salinity acclimation. However, while the transcriptional regulation of Na(+)/K(+)-ATPase in the teleost gill has been well documented the potential for mRNA regulation to facilitate rectal gland plasticity during salinity acclimation in elasmobranchs has not been examined.