Toxicokinetics/toxicodynamics with damage feedback improves risk assessment for tilapia and freshwater clam exposed to arsenic

Wei Yu Chen, Chung Min Liao, Yun Ru Ju, Sher Singh, Li John Jou, Bo Ching Chen, Jeng Wei Tsai

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


It has been proposed that irreversible responses of organisms exposed to contaminants are due to a systemslevel feedback. Here we tested this hypothesis by reanalyzing the published data on toxicokinetics and survival probability based on a systems-level threshold damage model (TDM) incorporating with a positive damage feedback to explore the steady-state response and dynamic behavior of damage for tilapia and freshwater clam exposed to waterborne arsenic (As). We found that ultrasensitivity appeared in As-tilapia and freshwater clam systems with Hill coefficient n C 4, indicating that the positive damage feedback mechanism has been triggered. We confirmed that damage can trigger a positive feedback loop that together with As stressor increases irreversibility. This study also showed that TDM with positive feedback gave a much better predictability than that of TDM at As concentrations ranging from 100 to 500 mg l-1 for freshwater clam, whereas for tilapia, two models had nearly same performance on predictability. We suggested that mortality-time profile derived Hill coefficient could be used as a new risk indicator to assess the survival probability for species exposed to waterborne metals. We anticipated that the proposed toxicokinetics/toxicodynamics with a positive damage feedback may facilitate our understanding and manipulation of complex mechanisms of metal susceptibility among species and improve current risk assessment strategies.

Original languageEnglish
Pages (from-to)485-495
Number of pages11
Issue number2
Publication statusPublished - 2012 Mar 1


  • Arsenic
  • Damage feedback
  • Ecotoxicology
  • Freshwater Clam
  • Tilapia
  • Toxicodynamics
  • Toxicokinetics

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Toxicology
  • Management, Monitoring, Policy and Law
  • Medicine(all)


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