title: Using the dioxin receptor-CALUX in vitro bioassay to screen marine harbor sediments for compounds with a dioxin-like mode of action.
abstract: The presence of dioxin-like compounds in sediments from harbors and reference sites along the Dutch coast was investigated using the dioxin receptor-chemically activated luciferase gene expression (DR-CALUX) bioassay. The DR-CALUX response varied between 0.2 and 136 ng/kg dry weight expressed in units of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency quotients (TEQ). The highest CALUX-TEQ values (> 50 ng TEQ/kg dry wt) were found in sediments from the center of the Port of Rotterdam and from the North Sea canal near Amsterdam. The DR-CALUX activity of harbor sediments was classified by setting guideline values. None of the 257 harbor sediment samples investigated exceeded the maximum value of 1,000 ng TEQ/ kg, while 94% of the samples fail the target value of 2 ng TEQ/kg. Threshold values (25 and 50 ng TEQ/kg) are intended as pass/ fail criteria for offshore disposal of dredged material and were exceeded in 12 and 3% of the samples, respectively. DR-CALUX response did not always match with contamination of polychlorinated biphenyls (PCBs) as determined in bulk sediments (sigma7-PCB ranging from < 1 to 456 microg/kg dry wt). Concentrations of planar PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated-dibenzofuranes (PCDFs), polybrominated biphenyls (PBBs), and polybrominated-diphenylethers (PBDEs) were determined in 20 selected sediment extracts. On average, PCDD/Fs explained 50% of the DR-CALUX activity and planar PCBs 6%. Further research is needed to elucidate the unexplained part of the DR-CALUX response. The DR-CALUX is a highly sensitive and reproducible bioassay that can usefully complement standard PCB analysis, improving the hazard assessment of the disposal of dredged material in the North Sea.
authors.affiliation: National Institute for Coastal and Marine Management/RIKZ, P.O. Box 20907, 2500 EX The Hague, The Netherlands. j.stronkhorst@rikz.rws.minvenw.nl
authors.forename: Joost
authors.initials: J
authors.lastname: Stronkhorst
authors.forename: Pim
authors.initials: P
authors.lastname: Leonards
authors.forename: Albertinka J
authors.initials: AJ
authors.lastname: Murk
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000473:pathology; D004147:Dioxins / Q000032:analysis* / Q000494:pharmacology; D004784:Environmental Monitoring / Q000379:methods*; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter; D019015:Geologic Sediments / Q000737:chemistry*; D008113:Liver Neoplasms / Q000201:enzymology / Q000473:pathology; D008156:Luciferases / Q000096:biosynthesis* / Q000235:genetics; D009426:Netherlands; D051381:Rats; D014407:Tumor Cells, Cultured / Q000201:enzymology / Q000473:pathology
chemical_list: D004147:Dioxins; D008156:Luciferases