Ultra-trace measurement of Dechloranes to investigate food as a route of human exposure

Differences in mirex [dechlorane] and dechlorane plus [syn- and anti-] concentrations observed in Canadian human milk

As part of the pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study, human milk samples were collected between 2008 and 2011, and analyzed for mirex, an organochlorine insecticide and flame retardant, in addition to dechlorane plus (syn- and anti-DDC-CO), the flame retardant replacement for mirex. Mirex was analyzed separately, using a method for the analysis of existing organochlorine insecticides, while the presence of DDC-CO isomers was determined using a method developed for the detection of emerging flame retardants. Mirex was detected in all samples analyzed (n = 298), while syn- and anti-DDC-CO were present in 61.0% and 79.5% of the samples, respectively (n = 541). Mirex concentrations have declined in human milk since the 1990s. Since this is the first pan-Canadian dataset reporting DDC-CO concentrations in human milk, no temporal comparisons can be made. Maternal age was correlated with concentrations of both compounds although parity did not impact concentrations of either analyte. Given the presence of this relatively recently identified flame retardant (DDC-CO) in human milk from women across Canada, studies to identify dominant sources of this compound are critical. Despite low concentrations of environmental chemicals in human milk from Canadian women, Health Canada supports breastfeeding of infants because of the important health benefits to both the mothers and their infants.

Chlorinated Flame-Retardant Dechlorane 602 Potentiates Type 2 Innate Lymphoid Cells and Exacerbates Airway Inflammation

Chlorinated flame-retardant dechloranes are emerging substitutes for restricted flame retardants. Recent studies have demonstrated that they are accumulated in wildlife and detectable in humans; however, their effects on human health are poorly understood. Here, for the first time, we revealed that widely used chlorinated flame-retardant dechlorane 602 (Dec 602) exacerbated airway inflammation in two mouse models induced by house dust mite (HDM) or IL-33, respectively. Deteriorated airway inflammation by Dec 602 was associated with a higher production of type 2 cytokines including IL-4, IL-5, and IL-13, and IgE, accompanied by enhanced mRNA expression of proinflammatory cytokines such as TNF-α and IL-6. Mechanistically, we found that Dec 602 directly potentiated mouse and human group 2 innate lymphoid cells and, as such, promoted airway inflammation even in the absence of conventional T cells in Rag ^-/- mice. These findings provide novel immunological insights necessary for further studies of the health impact of emerging flame-retardant dechloranes including Dec 602.

Dechlorane Plus and Related Compounds in Food-A Review

Dechlorane Plus is a polychlorinated compound which has exclusively anthropic origin. This compound has been manufactured for close to 60 years for various applications, but mainly as flame retardant. Dechlorane Plus and other Dechlorane-related compounds (DRCs) are currently marketed as a replacement for Dechlorane, also known as Mirex, banned in 1978. These compounds share comparable properties to persistent organic pollutants (POPs), such as persistence in the environment, high lipophilicity, bioaccumulation through the food web and adverse effects on the environment and human health. Despite their long production history, they have been only recently reported in various environmental compartments, such as air, soil, and foodstuff. The aim of this review is to provide a picture of the current state of knowledge on worldwide DRC levels in food, in order to highlight gaps and research needs. The review compares the data on DRC contamination available in literature, considering different food categories and sampling country. In addition, it is specified whether the data were obtained from studies on foodstuff to estimate dietary intake, to evaluate the contamination near the e-waste treatment area or for environmental monitoring purposes.

Levels of persistent organic pollutants (POPs) in foods from the first regional Sub-Saharan Africa Total Diet Study

For the first time, a multi-centre Total Diet Study was carried out in Benin, Cameroon, Mali and Nigeria. We collected and prepared as consumed 528 typical fatty foods from those areas and pooled these subsamples into 44 composites samples. These core foods were tested for a wide spectrum of POPs, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), brominated flame-retardants (BFRs), organochlorine compounds (OCs), perfluoro alkyl substances (PFAS) and chlorinated flame retardants (CFRs). The POPs contamination levels were similar or lower than those reported in total diet studies previously conducted worldwide. In most cases, core foods belonging to fish food group presented higher POPs concentrations than the other food groups. Interestingly, we observed a difference in both contamination profile and concentration for smoked fish compared to non-smoked fish. Such finding suggests that the smoking process itself might account for a large proportion of the contamination. Further investigation would require the assessment of combustion materials used to smoke fish as a potential vehicle, which may contribute to the dietary exposure of the studied populations to POPs.

Assessment of Dechlorane Plus and related compounds in foodstuffs and estimates of daily intake from Lebanese population

Dechlorane Related Compounds (DRCs), including Dechlorane Plus (syn/anti-DP or syn/anti-DDC-CO) and related compounds (Dec-601 or DDC-ID, Dec-602 or DDC-DBF, Dec-603 or DDC-Ant and Chlordene Plus or DDC-PDD), are a group of polychlorinated flame retardants of concern since they were first reported in various environmental and biota matrices about one decade ago. In this work, we investigated the dietary intake of the Lebanese population to these lipophilic environmental contaminants upon the evaluation of selected foodstuff contamination. Collected food samples (n = 58) were selected to be representative of the lipid fraction of the whole diet of the Beiruti population. The samples were analysed using pressurized liquid extraction, silica multilayer column followed by gel permeation chromatography for purification and GC-EI-HRMS for separation and detection. Detection frequency of at least one compound among Dechlorane Plus (syn-DP and anti-DP), Dechlorane 602, 603 and Chlordene Plus) was 91%. The mean concentrations of ∑₆DRCs, by food group, ranged from 4.7 to 29.5 pg g^-1 wet weight in lowerbound (LB) and from 6.7 to 76.9 pg g^-1 wet weight in upperbound (UB). Based on food habits, the dietary intake of Beiruti adults was estimated to be between 3.71 (LB) and 5.61 (UB) ng day^-1. Dechlorane Plus and Dechlorane 602 were the dominant compounds, contributing to 70 and 24% of the total intake (LB value), respectively. This study reports for the first time the occurrence of Dechloranes in Lebanese foods and proposes corresponding deterministic dietary exposure scenario.

Occurrence of Dechlorane Plus and related compounds in catfish (Silurus spp.) from rivers in France

Dechlorane related compounds (DRCs), including Dechlorane Plus (syn-DP and anti-DP), Dechlorane-601, -602, -603 and Chlordene Plus (CP), constitute a group of polychlorinated flame retardants (FRs) that are still of industrial use. In particular, DRCs have been detected in various environmental matrices and in different aquatic and terrestrial biota, thus exhibiting bioaccumulation and biomagnification potentials. The present study aimed at producing first occurrence data of a range of DRCs in Silurus spp. samples from different rivers located in France. Determination was carried out by gas chromatography high-resolution mass spectrometry after a sample clean-up based on a multilayer silica column and gel permeation chromatography. The concentration of monitored ΣDRCs ranged from 1.58 to 408 pg g^-1 wet weight (54-11100 pg g^-1 lipid weight). The fractional abundance of syn- and anti-DP stereoisomers was similar to that reported by other studies with an average equal to 0.60. Dec-601 was not detected in any sample. Detection frequencies ranged between 34 and 100% for other DRCs. Investigated correlations between DRCs and polychlorobiphenyls (PCBs) suggest a link with lipid content but independent contamination sources.

Development and optimization of gas chromatography coupled to high resolution mass spectrometry based method for the sensitive determination of Dechlorane plus and related norbornene-based flame retardants in food of animal origin

An analytical method has been developed for the trace determination of 10 dechlorane-related compounds (DRCs) in food products by gas chromatography - high resolution mass spectrometry (GC-HRMS). The highest sensitivity of this instrumental analysis method was achieved by selection of the GC column type, optimization of the heated zones within the instrument, and adjusting the electron impact energy. The efficiency of solid phase extraction as clean-up procedure was also optimized. Two different types of cartridges - neutral silica gel and Florisil^®, as well as seven organic solvents or their mixtures - n-hexane, cyclohexane, acetone, toluene, n-hexane/ethyl acetate, n-hexane/acetone, and n-hexane/dichloromethane - were evaluated. The analytical method was characterized as selective, precise, accurate, and linear over the concentration ranges from 1.00 to 100 pg μL^-1 for DRCs. Ultra-trace level sensitivity was achieved with the instrumental limits of quantification (i-LOQs) varying from ∼0.01 pg to ∼ 1 pg and method limits of quantification (m-LOQs) by the analysis of 10 g of sample varying from ∼0.04 to ∼ 5 pg g^-1. The developed method was successfully applied for the analysis of food samples and the analyses revealed the presence of majority of selected DRCs, with the Dechlorane Plus (DP) isomers occurring to a greater extent, pointing to the highest levels in cod liver and other fish products.

Measurement of emerging dechloranes in human serum using modulated gas chromatography coupled to electron capture negative ionization time-of-flight mass spectrometry

RATIONALE

Quite recently, the presence of significant amounts of several emerging Dechlorane (Dec) flame retardants (FRs) was reported in environmental and biota samples, principally from Canada and China, but also from Europe. Several molecules were identified, e.g. Dec 602, 603, 604, Dechlorane Plus (DP), and Chlordene Plus (CP). Gas chromatography (GC) coupled to electron ionization (EI) high-resolution mass spectrometry (HRMS) is typically used for their measurement in various matrices based on hexachlorocyclopentadiene (HCCPD) fragment ions at m/z 271.8102/273.8072.

METHODS

We investigated the use of GC with cryogenic zone compression and electron capture negative ionization time-of-flight mass spectrometry (CZC-GC/ECNI-TOFMS) to measure Dechlorane compounds at low levels in human serum. The TOFMS instrument provided a resolving power of 5000 (FWHM) with an acquisition rate of 25 Hz and was equipped with a specific low thermal emission filament, which allowed it to perform reproducibly in ECNI mode at ion source temperatures as low as 140°C, thus yielding a signal for the molecular ion cluster.

RESULTS

The method provided comparable sensitivity to the GC/EI-SectorHRMS technique used in selected ion monitoring (SIM) mode, and specificity for the target Dechlorane compounds. The method was applied on human serum samples and quantification was performed for Dec 602, Dec 603, and CP, ranging from 0.1 to 10 ng/g lipid weight levels. The main drawbacks of the method are the high instrument detection limits (IDLs) obtained for DP and Dec 604. The method would benefit from even softer ionization and better ion transmission.

CONCLUSIONS

The main advantages of the present method are the selectivity, as detection is based on the molecular ion signal, and the use of good mass accuracy combined with isotopic distribution calculation for molecular formulae investigation of halogenated compounds. This methodology should facilitate the monitoring of emerging Dechlorane contaminants in future studies, and possibly extend the scope to untargeted emerging analogues. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of Dechlorane Plus and related compounds (dechlorane 602, 603 and 604) in fish and vegetable oils

Dechlorane Plus (DP) is a flame retardant used as a substitute of Mirex since 1970s, but it was not detected in the environment until 2006. Since then, this compound and its main relatives, Dechlorane 602, 603 and 604, have been mainly studied in environmental matrices for monitoring purposes, but the dietary exposure to them has been hardly investigated so far. In the present study, we determined this family of compounds in fish and vegetable oil samples from Catalonia (Spain), most of them used as health supplements. Determination was carried out by gas chromatography-high resolution mass spectrometry (GC-HRMS), after a clean up in a multilayer silica column and preparative high performance liquid chromatography (HPLC) equipped with a pyrenyl(ethyl) column. Concentrations of Dechlorane compounds were between below the limit of detection and 384.2 pg g(-1). Although there are only few studies about the presence of these pollutants in food or feed, concentrations obtained indicated that these compounds are in the same order in fish and vegetable oil health supplements as the few other food and feed studies.