Modeling of DR CALUX bioassay response to screen PCDDs, PCDFs, and dioxin-like PCBs in farm milk from dairy herds.
A recent issue in the EU legislation is the evaluation of the toxicologically-equivalent contribution of dioxin-like polychlorobiphenyls (DL-PCBs) in addition to that coming from polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) as contaminants in foods for a total of 29 congeners. This fact is determining the need to revise analytical criteria both for confirmatory and screening analysis. In this work, a modeling was developed to check the reliability of the outcomes of the DR CALUX bioassay when applied to farm milk samples characterized by large differences in congener patterns. To reproduce some field conditions where DL-PCB contributions up to 90% of total WHO-TEQs (HRGC-HRMS assessment) were recorded in dairy products, goat milk samples from a common bulk were fortified at different TEQ levels with mixtures containing either PCDDs and PCDFs or non-ortho substituted DL-PCBs. Fortification ranged approximately 4.5-15 pgWHO-TEQ/g fat. Based on the results, DR CALUX relative potency value (REP) of DL-PCB 126 was estimated 0.061 against the canonical WHO-TEF of 0.1. The value of 0.061 together with the other DR CALUX REPs from the literature for the remaining 28 congeners were used to model DR CALUX response (C-TEQs) in milk samples with different congener patterns. The theoretical underestimation of DR CALUX data could be mitigated by correcting the latter with the linear correlation experimentally obtained between C-TEQs and the WHO-TEQs. Under these conditions, the use as calibrants of reference samples with different analytical patterns could help those laboratories involved in a high throughput routine to set the most appropriate decision limits to optimize screening output.
Fochi
Igor
I
Istituto Superiore di Sanità, Toxicological Chemistry Unit, Viale Regina Elena, 299 I-00161 Rome, Italy. igor.fochi@iss.it
Brambilla
Gianfranco
G
De Filippis
Stefania P
SP
De Luca
Silvia
S
Diletti
Gianfranco
G
Fulgenzi
Annarita
A
Gallo
Pasquale
P
Iacovella
Nicola
N
Scortichini
Giampiero
G
Serpe
Luigi
L
Vinci
Floriana
F
di Domenico
Alessandro
A
D000465:Algorithms; D000818:Animals; D001572:Benzofurans / Q000032:analysis / Q000633:toxicity*; D001681:Biological Assay / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003627:Data Interpretation, Statistical; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D006041:Goats; D016014:Linear Models; D008892:Milk / Q000737:chemistry*; D015233:Models, Statistical; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000633:toxicity; D011108:Polymers / Q000032:analysis / Q000633:toxicity*; D012015:Reference Standards; D015203:Reproducibility of Results
D001572:Benzofurans; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D011108:Polymers; C016068:polychlorodibenzofuran; D011078:Polychlorinated Biphenyls