Kaolinic clay derived PCDD/Fs in the feed chain from a sorting process for potatoes

• Published in: Chemosphere (Oxford) 2010, Vol.78 (2), p.99-105
• Main Authors: Hoogenboom, Ron, Zeilmaker, Marco, Eijkeren, Jan van, Kan, Kees, Mengelers, Marcel, Luykx, Dion, Traag, Wim
• Format: Article
• Language: English
• Subjects: Aluminum Silicates - chemistry; Animal Feed; Animals; ball clay; Benzofurans - analysis; Benzofurans - chemistry; Benzofurans - pharmacokinetics; Cattle; contamination; dibenzo-p-dioxins; Dioxins; food; Incident; Kaolin - chemistry; Kaolinic clay; Milk; Milk - chemistry; origin; PB-PK model; pcbs; pcdfs; Polychlorinated Dibenzodioxins - analogs & derivatives; Polychlorinated Dibenzodioxins - analysis; Polychlorinated Dibenzodioxins - chemistry; Polychlorinated Dibenzodioxins - pharmacokinetics; Polymers - analysis; Polymers - chemistry; Polymers - pharmacokinetics; Solanum tuberosum; Solanum tuberosum - chemistry; united-states
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2009.10.016

At the end of 2004, during a routine monitoring project, high levels of PCDDs in milk from two farms were found. Using a bioassay and the congener patterns obtained by HRGC/HRMS, the source was traced back to the use of kaolinic clay for sorting potatoes in a production process of French fries. Rest products, especially peelings after scrubbing, were used as feed for dairy cows. Levels of PCCD/Fs in this product amounted to 44 ng WHO 1998-TEQ kg −1 (88% dw). The maximum level observed in milk was 20 pg WHO 1998-TEQ g −1 fat. A Physiologically Based PharmacoKinetic (PB-PK) model was used to model three data obtained before eliminating the source in order to estimate the starting time of the contamination of the cows, the steady-state level after prolonged contamination and the kinetics of the decrease in the levels after removal of the source. Samples of milk were continuously collected for several months showing a decrease to levels below the product limit of 3 pg WHO 1998-TEQ g −1 fat within 2 months, in excellent agreement with the decrease predicted by the PB-PK model. Different batches of clay were sampled and analysed, showing varying levels of especially PCDDs. All clays were confirmed to be kaolinic clay using X-ray analysis. Other by-products used for animal feed were also contaminated and led to precautionary measures at a few hundred farms, especially pig farms. However, levels in other animal derived products like pig meat did not exceed the product limits.