Evaluation of the use of CALUX results for dioxins and dioxin-like PCBs analysis for quantitative human exposure assessments

Identification of an aryl hydrocarbon receptor agonistic disperse dye in commercially available textile products by effect-directed analysis

Textile products contain various chemicals, making safety evaluation complex. We conducted an exploratory investigation of aryl hydrocarbon receptor (AhR) agonists in textile products using effect-directed analysis (EDA), which combines biological assays and chemical analysis. A cell-based assay was employed to detect the activation of the AhR, using a cell line that expresses the AhR-responsive luciferase gene. Testing the extracts of 10 commercially available textile products revealed high AhR agonistic activities in two of them. To identify the specific AhR agonist in one product, the sample was fractionated using chemical techniques. The active fractions were further separated using liquid chromatography. Confirmation of the active component was achieved through Orbitrap-liquid chromatography/mass spectrometry (MS), which matched the retention time and tandem MS spectrum with the standard for Disperse Violet 93:1. It has also been confirmed that Disperse Violet 93:1 activates the AhR in a dose-dependent manner. Additionally, the AhR agonistic properties of other disperse dyes were examined, leading to the discovery of Disperse Blue 291 and Disperse Blue 373 as AhR agonists. These disperse dyes had not been previously recognized as AhR agonists. Textile products have received little attention as potential sources of exposure to AhR agonists. Activation of the AhR has both positive and negative effects on human health. Therefore, conducting detailed exposure assessments and toxicity evaluations is crucial to comprehensively assess the health risks associated with these substances. The identification of disperse dyes that activate the AhR suggests that it is now possible to conduct these detailed assessments in the future.

Health risk assessment of exposure to polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in swordfish from the Mediterranean Sea

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in fish samples have been investigated in many previous studies. However, the available data regarding this issue in low- and middle-income countries are very scarce, and no study has been performed in Algeria yet. Therefore, this work aimed to determine the levels of PCDD/Fs and DL-PCBs in swordfish (Xiphias gladius) caught in three regions of the Algerian coasts, and the health risk associated with these contaminants was assessed. The PCDD/Fs and DL-PCBs were analyzed in 37 fish samples from Algiers, Bejaia, and Oran using the DR-CALUX bioassay method. The overall mean (and standard deviation) of PCDD/Fs and DL-PCBs concentrations in swordfish from Algiers, Bejaia, and Oran were 0.19 (0.13), 0.27 (0.24), and 0.08 (0.05) pg TEQ g-1 wet weight (ww), respectively, which were lower than the national and European regulatory limits. Daily and weekly intake values of PCDD/F and DL-PCB were higher for the samples from Bejaia (0.45 and 3.15 pg TEQ kg-1 body weight (bw) per day and week, respectively) and for the samples from Algiers (0.31 and 2.17 pg TEQ kg-1 bw per day and week, respectively), which were higher than the tolerable weekly intake of 2 pg TEQ kg-1 bw per week recently established by the European Food Safety Authority. Overall, our findings indicate that swordfish consumption poses a risk to the Algerian consumer.

Comparing dioxin-like polychlorinated biphenyls in most consumed fish species of the Caspian Sea

Among polychlorinated biphenyls (PCBs), dioxin-like PCBs (DL-PCBs) are of the most concern for human health. In this study, the levels of 12 DL-PCBs congeners were measured in 125 fish samples of the Caspian Sea, Iran. Five fish species (Oncorhynchus mykiss, Vimba vimba, Cyprinus carpio, Rutilus frisii kutum and Chelon saliens) were collected from 5 coastal cities of the Caspian Sea (25 samples per each city). Duncan's multi-scope test was used to compare the mean of DL-PCBs in different fish species and different cities. Probabilistic risk of exposure to DL-PCBs and sensitivity analysis were assessed using Monte Carlo simulation approach. The average (standard deviation) of DL-PCBs in fish samples ranged from 232 (16) to 1156 (14) pg/g lipids. The total maximum concentration was detected in Cyprinus carpio from Bandar Anzali, the minimum in Vimba vimba from Chalos. In all samples, non-carcinogenic risk of exposure to DL-PCBs was in safe level (Hazard Quotient < 1). In contrast, the lifetime cancer risk estimated for Bandar Anzali, Bandar Torkaman, and Rasht exceeded the threshold value of 1 × 10^-6 suggested by United States Environmental Protection Agency. Sensitivity analysis indicated that the concentration of DL-PCBs and exposure frequency were the most effective parameters in increasing carcinogenic risk.

CALUX bioassay: a cost-effective rapid screening technique for screening dioxins like compounds

Xenobiotic detection systems-chemically activated luciferase expression (XDS-CALUX) bioassay in determining the toxic equivalency (TEQ) of PCDD/Fs from contaminated sites reported in several papers has been discussed in this study. CALUX bioassay method has been validated by an effective combined column clean-up system followed by addition of samples to monolayer cell cultures of H1L6.1c3 cell line in 96 well plates. Cultures are then examined under microscope after 24 h incubation followed by rinsing with 75 μL phosphate buffer saline and 30 μL of cell culture lysis. The response is observed in the luminometer and expressed in relative light unit (RLUs). CALUX-TEQ is estimated from a TCDD standard curve for unknown samples. Quality control in CALUX is done by selecting the range of CALUX values falling in the center of the linear standard curve. For developing nations CALUX biossay can be used as a cost effective and rapid screening technique for screening xenobiotic compounds from the hotspots like open solid waste burning sites, informal e-waste recycling workshops and industrial zones where constant monitoring for such compounds is required.

A survey of dioxin-like contaminants in fish from recreational fishing

The dioxin and dioxin-like compounds are regarded as one of the most toxic group of environmental contaminants. Food for the commercial market is regularly monitored for their dioxin levels and the concentration allowed in food is strictly regulated. Less is known about locally caught fish from recreational fishing, which is often brought home for consumption. This can be fish caught from nearby lakes or streams or fish with marine origin close to industrial areas or harbours that are not regularly monitored for their dioxin levels. In this study, we established collaboration with schools in 13 countries. We received 203 samples of 29 different fish species of which Atlantic cod was the most abundant followed by brown trout and pollock. In general, the majority of samples from the participating countries had low concentrations (between 0.1 and 0.2 pg/g chemical-activated luciferase gene expression toxic equivalency wet weight (CALUX TEQ w.w.)) of dioxins and dioxin-like PCBs. Only 18 samples had concentrations above 1 pg/g CALUX TEQ w.w., and only 2 dab samples had concentration above maximum levels set by the European Commission. The Atlantic cod samples showed a significant reduction in the concentrations of dioxins with increasing latitude indicating less contamination of dioxin and dioxin-like compounds in the north of Norway. The results indicate that a moderate consumption of self-caught fish at presumed non-contaminated sites does not represent a major risk for exposure to dioxins or dioxin-like compounds at concentrations associated with adverse health effects. Recreational fishermen should, however, obtain knowledge about local fish consumption advice.

Aryl hydrocarbon receptor agonists in European herring gull (Larus argentatus) eggs from Norway

Herring gull eggs from two locations in Norway, an island situated in the north (Musvær, 69.88° N, 18.55° E) and an island in the southeast (Reiaren, 59.15° N, 10.46° E) of the country, were analyzed for the presence of aryl hydrocarbon receptor (AhR) agonists. AhR agonist activity was determined using the dioxin-responsive chemically activated luciferase expression (DR-CALUX) assay to calculate the toxic equivalent quotient (TEQ)CALUX. TEQCALUX ranged from 16 to 401 pg TEQ/g lipid in the samples from the north (n = 11) and between 6 and 360 pg TEQ/g lipid (n = 12) in the southeastern samples. The large variance between the individual samples is postulated to be due to different feeding habits of individual birds. The levels of AhR agonists detected might lead to adverse effects for the developing embryo or to a significant increase of contaminant load for human consumers of eggs.