The growing knowledge of the genetic polymorphisms of enzymes metabolising xenobiotics in humans and their connections with individual susceptibility towards toxicants has created new and important interfaces between human epidemiology and experimental toxicology. The results of molecular epidemiological studies may provide new hypotheses and concepts, which call for experimental verification, and experimental concepts may obtain further proof by molecular epidemiological studies. If applied diligently, these possibilities may be combined to lead to new strategies of human-oriented toxicological research. This overview will present some outstanding examples for such strategies taken from the practically very important field of occupational toxicology. The main focus is placed on the effects of enzyme polymorphisms of the xenobiotic metabolism in association with the induction of bladder cancer and renal cell cancer after exposure to occupational chemicals. Also, smoking and induction of head and neck squamous cell cancer are considered.

Genetic susceptibility to environmental toxicants : the interface between human and experimental studies in the development of new toxicological concepts

Chlorinated paraffins (CPs) in vegetable oils from the Dutch market and the effects of the refining process on their levels

Bromochloro alkanes (BCAs) have been manufactured for use as flame retardants for decades, and preliminary environmental risk screening suggests they are likely to behave similarly to polychlorinated alkanes (PCAs), subclasses of which are restricted as Stockholm Convention Persistent Organic Pollutants (POPs). BCAs have rarely been studied in the environment, although some evidence suggests they may migrate from treated-consumer materials into indoor dust, resulting in human exposure via inadvertent ingestion. In this study, BCA-C14 mixture standards were synthesized and used to validate an analytical method. This method relies on chloride-enhanced liquid chromatography-electrospray ionization-Orbitrap-high resolution mass spectrometry (LC-ESI-Orbitrap-HRMS) and a novel CP-Seeker integration software package for homologue detection and integration. Dust sample preparation via ultrasonic extraction, acidified silica cleanup, and fractionation on neutral silica cartridges was found to be suitable for BCAs, with absolute recovery of individual homologues averaging 66 to 78% and coefficients of variation ≤10% in replicated spiking experiments (n = 3). In addition, a total of 59 indoor dust samples from six countries, including Australia (n = 10), Belgium (n = 10), Colombia (n = 10), Japan (n = 10), Thailand (n = 10), and the United States of America (n = 9), were analyzed for BCAs. BCAs were detected in seven samples from the U.S.A., with carbon chain lengths of C8, C10, C12, C14, C16, C18, C24 to C28, C30 and C31 observed overall, though not detected in samples from any other countries. Bromine numbers of detected homologues in the indoor dust samples ranged Br1-4 as well as Br7, while chlorine numbers ranged Cl2-11. BCA-C18 was the most frequently detected, observed in each of the U.S.A. samples, while the most prevalent degrees of halogenation were homologues of Br2 and Cl4-5. Broad estimations of BCA concentrations in the dust samples indicated that levels may approach those of other flame retardants in at least some instances. These findings suggest that development of quantification strategies and further investigation of environmental occurrence and health implications are needed.

Detection of Bromochloro Alkanes in Indoor Dust Using a Novel CP-Seeker Data Integration Tool.

Abstract Chlorinated paraffins (CPs), also known as polychlorinated alkanes (PCA), are a very complex class of polyhalogenated compounds currently produced in unmatchable amounts for different industrial uses. Here, we investigated the presence of CPs in 21 rubber samples used as food contact materials from the German market. For this purpose, an analytical method was developed which consisted of (i) freezing and (ii) grounding of the material, (iii) removal of oligomers by adsorption chromatography, (iv) matrix destruction with sulfuric acid, and (v) GC/ECNI-MS screening and quantification. Three of the rubber samples were found to contain predominantly medium-chain CPs (MCCPs; C 14 - to C 17 -CPs) at 69, 113,000 and 341,000 mg/kg. The highest amount (corresponding with 34 weight-% CPs) was determined in one rubber band sample used to bundle a bunch of spring onions. A very high CP content of &gt;300,000 mg/kg in this rubber band sample was confirmed by quantitative 1 H NMR (qNMR) analysis. This rubber material was in direct contact with the onions and leaching of CPs into the food cannot be excluded. Even more, micro-abrasions of rubber could be unintentionally swallowed by the consumer and this CP exposure could be higher than the current CP intake via food. 

/pdf/chlorinated-paraffins-in-food-contact-materials-made-of-3o202l54.pdf

Chlorinated paraffins in food contact materials made of rubber from the German market

Bromochloro alkanes (BCAs) are a class of flame retardants similar in structure to polychlorinated alkanes (PCAs), which are the major component of short-chain chlorinated paraffins (SCCPs) listed as Persistent Organic Pollutants under the Stockholm Convention. BCAs have recently been detected for the first time in environmental samples. Due to the complete lack of commercially available analytical standards, no method for quantifying BCAs has been reported to date. In this study, 16 custom-synthesised standards with mixed bromine and chlorine halogenation and carbon chain lengths ranging from C 

Application of pattern deconvolution strategies for the estimation of bromochloro alkane concentrations in indoor dust samples

RATIONALE
Chlorinated paraffins (CPs) are a group of anthropogenic pollutants that consist of complex mixtures of polychlorinated n-alkanes of different chain lengths (~C10 to C30 ). Persistence, bioaccumulation, toxicity and long-range transport of short-chain chlorinated paraffins (SCCPs, C10 - to C13 -CPs) have prompted their classification as persistent organic pollutants (POPs) by the Stockholm Convention in 2017. Due to the varying chain lengths and chlorination degrees, quantification of SCCPs and medium-chain chlorinated paraffins (MCCPs; C14 - to C17 ) by GC/ECNI-MS-SIM is not only challenging but also very time consuming. Specifically, eight GC runs per sample are required for the comprehensive GC/ECNI-MS-SIM quantification of SCCPs and MCCPs. These efforts are high especially if the samples do not contain CPs above the limit of detection (LOD), subsequently.


METHODS
We developed a semi-quantitative and sensitive method for the examination of SCCPs and MCCPs in one GC run. This GC/ECNI-MS-SIM screening method was based on the recording of Cl- (m/z 35 & 37), Cl2 - (m/z 70 & 72), and HCl2 - (m/z 71 & 73) isotope ions and evaluating the ratios between them.


RESULTS
Correctness of the results of the screening method was verified by analysis of edible oils with and without CPs, CP standards as well as a technical CP mixture. PCBs and other polyhalogenated aromatic compounds, as well as brominated flame retardants do not form all of the fragment ions analyzed in the screening method.


CONCLUSIONS
After the screening, only CP-positive samples may need to be measured in detail. Measure time will already be gained in case of ~10% samples without CPs.

A fast GC/ECNI-MS-SIM screening method for short-chain and medium-chain chlorinated paraffins.

Brominated chlorinated paraffins (Br-CPs) are a comparably new compound class that features both Cl and Br on one or several alkane backbones. Due to legal restrictions in the use of conventional chlorinated paraffins (CPs), Br-CPs have the potential to become emerging contaminants. Currently, their determination is hampered by the lack of suitable reference standards. Here, we present a simple synthesis procedure with single chain alkanes that leads to Br-CPs with ∼4–8 chlorine and >0 to 4 bromine substituents according to gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS). The single-chain Br-CP mixtures were obtained by the shared chlorination and bromination of eight single-chain alkanes (C10- to C17) at two reaction times, respectively. The carbon content of the 16 single-chain Br-CP products, determined by elemental analysis (EA), ranged from 30.8 to 43.8 %. The typical hump peak known from CPs was detected with GC with flame ionization detection (GC/FID), electron capture detection (GC/ECD) and GC/ECNI-MS. The complexity indicated that low-resolution mass spectrometry is not sufficient for an adequate analysis of Br-CPs. A mathematical formula was developed which allows to calculate all possible combinations of Br and Cl that are in line with the carbon content. The proton magnetic resonance spectroscopy (1H NMR) spectra showed similarities to the ones of CPs with one chemical shift range for protons on nonhalogenated carbons and one for protons with one halogen on the same carbon. 

A simple laboratory method for the generation of mixed brominated-chlorinated paraffin single chain mixtures

Suszeptibilitätsmarker [Biomonitoring Methods in German language, 2004]

The digestive tract of ruminants is specialized in the digestion of various plant components. One of the largest parts of the stomach is the so‐called rumen, which contains a large number of micro‐organisms that may degrade or modify fatty acids, for example by β‐oxidation, chain elongation and/or hydrogenation.

Microbial incubations of 8‐phenyloctanoic acid and furan fatty acids in rumen fluid

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A fast GC/ECNI-MS-SIM screening method for short-chain and medium-chain chlorinated paraffins.

A simple laboratory method for the generation of mixed brominated-chlorinated paraffin single chain mixtures

Suszeptibilitätsmarker [Biomonitoring Methods in German language, 2004]

Microbial incubations of 8‐phenyloctanoic acid and furan fatty acids in rumen fluid