Levels and Congener Distributions of PCDDs, PCDFs and Co-PCBs in Japanese Retail Fresh and Frozen Vegetables

Abstract

To evaluate dioxin contamination in retail vegetables, congener analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were performed on sixty varieties of fresh vegetables including cereals and mushrooms, obtained from Japanese supermarkets in 2002. The toxic equivalent quantity (TEQ) levels for dioxins in samples ranged from῍0.001 to 0.089 pg-TEQ/g wet weight, when undetected and trace were taken as zero. Among the samples, dioxins were generally detected in green leafy vegetables. The highest TEQ value was for mulukhiya (0.089 pg-TEQ/g), followed by spinach and komatsuna (Japanese mustard spinach) (0.077 and 0.074 pg-TEQ/g, respectively). Additionally, the dioxin levels in seventeen varieties of frozen vegetables were also determined, and showed TEQ values ranging from῍0.001 to 0.080 pg-TEQ/g. The total TEQ in commercial vegetables mainly reflected the levels of 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3῍,4,4῍,5-PeCB (#126) (the sum of them represented 63῏ of the total TEQ).

Evaluation of Exposure to Chemical Substances through Foods-Exposure to Pesticides, Heavy Metals, Dioxins, Acrylamide and Food Additives in Japan-

“…Apart from the total diet study, we applied the guideline methods established by the MHLW to various foods, [3][4][5] and also improved them. [6][7][8][9] The analysis of dioxins with HRGC/HRMS is a long process.…”

Levels of Organic Pollutants in Vegetables and Human Exposure Through Diet: A Review

“…40 Due to their toxicity, as expected, the total TEQ levels are most of the times dominated by 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, and 2,3,4,7,8-PeCDF for PCDD/Fs and PCB126 for co-PCBs in many vegetable samples from Japan. 4,40,41 Regarding DL-PCBs, the mean WHO-TEQs were <0.001 pg g −1 in market cabbage samples in Belgium, Italy, Spain, and Portugal. 7 Relatively high WHO-TEQs for PCBs were observed in Taizhou, China, a site where global transformers recycling takes place.…”

“…In most studies, PCB-138 and -153 were the most abundant of the seven indicator PCBs, 10,17 while PCB-105, -118, and -77 had the highest concentrations among the DL-PCBs. 10,40,41 The relative abundance of heavier PCBs is expected, due to the higher octanol-water partition coefficients (K OW ). According to the study of Grassi et al, 10 PCBs uptake by vegetables is also species specific.…”

“…Other congeners were detected only in one sample each. 4 OCDD was the most abundant congener in almost all vegetable samples, 4,9,[40][41][42][43][44] reflecting the ambient air dioxins profile. 45 …”

Dioxin Concentrations in Commercial Health Tea Materials in Japan

“…10) Extraction and Cleanup Procedure --The method of extraction and cleanup followed that of the tentative guideline for the analysis of dioxins in foods in Japan. 11) Briefly, 50 g of homogenized tea material was spiked with a mixture of 13 C-labeled internal quantitative standards [seventeen PCDD/Fs and twelve dioxin-like PCBs that have toxic equivalency factor (TEF) values proposed by the World Health Organization (WHO)], then extracted twice by shaking with acetone-n-hexane (1 : 1, total 200-360 ml) for 1 hr at room temperature, and filtered (0.8 µm filter, GPF filter paper of Kiriyama, Tokyo, Japan). After extraction, sulfuric acid treatment and column chromatography (CC) procedures (silver nitrate-silica gel CC, alumina CC, and activated carbon mixed silica gel CC) were carried out for cleanup, and each fraction obtained was spiked with 13 C-labeled recovery standards before analysis by high-resolution gas chromatography (HRGC)/highresolution mass spectrometry (HRMS).…”