Variability in the dynamics of mortality and immobility responses of freshwater arthropods exposed to chlorpyrifos

Research output: Contribution to journalArticleAcademicpeer-review

46 Citations (Scopus)

Abstract

The species sensitivity distribution (SSD) concept is an important probabilistic tool for environmental risk assessment (ERA) and accounts for differences in species sensitivity to different chemicals. The SSD model assumes that the sensitivity of the species included is randomly distributed. If this assumption is violated, indicator values, such as the 50% hazardous concentration, can potentially change dramatically. Fundamental research, however, has discovered and described specific mechanisms and factors influencing toxicity and sensitivity for several model species and chemical combinations. Further knowledge on how these mechanisms and factors relate to toxicologic standard end points would be beneficial for ERA. For instance, little is known about how the processes of toxicity relate to the dynamics of standard toxicity end points and how these may vary across species. In this article, we discuss the relevance of immobilization and mortality as end points for effects of the organophosphate insecticide chlorpyrifos on 14 freshwater arthropods in the context of ERA. For this, we compared the differences in response dynamics during 96h of exposure with the two end points across species using dose response models and SSDs. The investigated freshwater arthropods vary less in their immobility than in their mortality response. However, differences in observed immobility and mortality were surprisingly large for some species even after 96h of exposure. As expected immobility was consistently the more sensitive end point and less variable across the tested species and may therefore be considered as the relevant end point for population of SSDs and ERA, although an immobile animal may still potentially recover. This is even more relevant because an immobile animal is unlikely to survive for long periods under field conditions. This and other such considerations relevant to the decision-making process for a particular end point are discussed.
Original languageEnglish
Pages (from-to)708-721
JournalArchives of Environmental Contamination and Toxicology
Volume60
Issue number4
DOIs
Publication statusPublished - 2011

Keywords

  • species sensitivity distributions
  • marmorkrebs marbled crayfish
  • acute toxicity
  • pulsed exposure
  • life stages
  • time
  • chemicals

Fingerprint Dive into the research topics of 'Variability in the dynamics of mortality and immobility responses of freshwater arthropods exposed to chlorpyrifos'. Together they form a unique fingerprint.

Cite this