Mathematical model developed for environmental samples: Prediction of GC/MS dioxin TEQ from XDS-CALUX bioassay data

David J. Brown, Jean Orelien, John D. Gordon, Andrew C. Chu, Michael D. Chu, Masafumi Nakamura, Hiroshi Handa, Fujio Kayama, Michael S. Denison, George C. Clark

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Remediation of hazardous waste sites requires efficient and cost-effective methods to assess the extent of contamination by toxic substances including dioxin-like chemicals. Traditionally, dioxin-like contamination has been assessed by gas chromatography/high-resolution mass spectrometry (GC/MS) analysis for specific polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyl congeners. Toxic equivalency factors for these congeners are then used to estimate the overall dioxin toxic equivalency (TEQ) of complex mixtures found in samples. The XDS-CALUX bioassay estimates contamination by dioxin-like chemicals in a sample extract by measuring expression of a sensitive reporter gene in genetically engineered cells. The output of the XDS-CALUX assay is a CALUX-TEQ value, calibrated based on TCDD standards. Soil samples taken from a variety of hazardous waste sites were measured using the XDS-CALUX bioassay and GC/MS. TEQ and CALUX-TEQ from these methods were compared, and a mathematical model was developed describing the relationship between these two data sets: log(TEQ) = 0.654 x log(CALUX-TEQ) + 0.058-(log(CALUX-TEQ))2. Applying this equation to these samples showed that predicted and GC/MS measured TEQ values strongly correlate (R2 = 0.876) and that TEQ values predicted from CALUX-TEQ were on average nearly identical to the GC/MS-TEQ. The ability of XDS-CALUX bioassay data to predict GC/MS-derived TEQ data should make this procedure useful in risk assessment and management decisions.

Original languageEnglish (US)
Pages (from-to)4354-4360
Number of pages7
JournalEnvironmental Science and Technology
Issue number12
StatePublished - Jun 15 2007

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry


Dive into the research topics of 'Mathematical model developed for environmental samples: Prediction of GC/MS dioxin TEQ from XDS-CALUX bioassay data'. Together they form a unique fingerprint.

Cite this