Distributions and biomagnification of polybrominated diphenyl ethers in a grassland ecosystem food chain

Persistent organic pollutants and heavy metals in Ghanaian environment: a systematic review of food safety implications

Advances in industrial and technological innovations have led to significant socio-economic benefits, but with overwhelming negative impacts on the environment. These impacts include the infiltration of organic contaminants into soil, water, and air, posing a threat to the environment and public health. Polybrominated diphenyl ethers (PBDEs), heavy metals, and polycyclic aromatic hydrocarbons (PAHs) are increasingly released as waste, endangering the environment. In countries like Ghana, where regulations are weakly enforced, industrial waste is released uncontrollably, posing threats to public health, environmental integrity, and food systems. This study systematically evaluated existing literature on PBDEs, heavy metals, PAHs, and organic contaminant exposure in Ghana and proposes a roadmap for achieving food safety and protecting the environment and human health. The research identified high mobility of specific heavy metals and risks associated with PBDEs and PAHs in sediments, dumpsites, and various food items. Unregulated dumping of electronic waste with PBDEs raised environmental concerns. An integrated approach is needed to address the multifaceted impact of organic pollutants on public health and ecosystems. Urgent implementation of effective environmental management strategies and regulatory measures is crucial. The study proposed short- to mid-term priorities emphasising the need to foster collaboration and implementing global measures. The mid- to long-term strategy includes a national information surveillance system, local monitoring capacity development, and integrating land contamination controls with food safety legislation. These measures would mitigate risks, ensure sustainable practices, and improve overall food safety management in Ghana, serving as a model for regions facing similar challenges with diverse pollutants.

New brominated flame retardant decabromodiphenyl ethane (DBDPE) in water sediments: A review of contamination characteristics, exposure pathways, ecotoxicological effects and health risks

As an alternative to polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) has become one of the most important new brominated flame retardants (NBFRs). However, little is known about whether this emerging contaminant may has an environmental fate similar to PBDEs. Sediments are the main sink for DBDPE in the aqueous phase. Worldwide concentration data, since it was first found in sediments to date, have been collated, and the following conclusions have been drawn. (1) DBDPE concentrations in sediments have increased rapidly, often with a higher risk of contamination in source discharge areas. Compared with other countries, DBDPE contamination in China is more severe, especially in Guangdong Province, which is closely related to its being an e-waste dismantling area. (2) The amount of DBDPE in surface sediments has exceeded that of legacy brominated flame retardants (BFRs), and data recorded in sediment cores also corroborate that DBDPE is replacing decabromodiphenyl ether (BDE-209) as one of the most dominant NBFRs in the environment. (3) The exposure pathways of DBDPE include dietary intake, air or indoor dust intake, cutaneous absorption and endogenous exposure. For sediments, dietary exposure and endogenous exposure pathways need to be considered. Sediment DBDPE can enter the human body through bioenrichment such as contaminated seafood and the food chain. (4) DBDPE can exhibit neurotoxicity, thyrotoxicity, reproductive and developmental toxicity, hepatotoxicity and oxidative stress in organisms. Long-term DBDPE exposure may increase hyperthyroidism risk and inhibit normal cells activity. This review focuses on the distribution characteristics and exposure risks of DBDPE in global water sediments, providing a strong reference for environmental management and related legal policy formulation. The next steps are to focus on continuous source monitoring, process control and sediment clean-up of DBDPE. The development of sustainable water management options for waste microplastics (MPs) and e-waste spiked with DBDPE is a priority.

A pretreatment method combined matrix solid-phase dispersion with dispersive liquid-liquid micro-extraction for polybrominated diphenyl ethers in vegetables through quantitation of gas chromatography-tandem mass spectrometry (GC-MS)

Herein, a novel pretreatment method for extraction of polybrominated diphenyl ethers (PBDEs) using matrix solid phase dispersion (MSPD) and depth purification using dispersive liquid-liquid micro-extraction (DLLME) from vegetables was designed. The vegetables included three leafy vegetables (Brassica chinensis, Brassica rapa var. glabra Regel and Brassica rapa L.), two root vegetables (Daucus carota and Ipomoea batatas (L.) Lam.), and Solanum melongena L. First, the freeze-dried powders of vegetables and sorbents were evenly ground to a mixture, which was then loaded into a solid phase column containing two molecular sieve spacers, one positioned at the top and the other at the bottom. The PBDEs were eluted with a small amount of solvent, concentrated, redissolved in acetonitrile, and then mixed with extractant. Next, 5 mL water was added to form an emulsion and centrifuged. Finally, the sedimentary phase was collected and injected into a gas chromatography-tandem mass spectrometry (GC-MS) system. The main factors such as the type of adsorbent, ratio of sample mass and adsorbents, volume of elution solvent used in the MSPD process, as well as the types and volume of dispersant and the, extractant used in DLLME were all evaluated using the single factor method. Under optimal conditions, the proposed method showed good linearity (R² > 0.999) within the range of 1 to 1000 g kg^-1 for all PBDEs and satisfactory recoveries of spiked samples (82.9-113.8%, except for BDE-183 (58.5-82.5%)) and matrix effects (-3.3-18.2%). The limits of detection and the limits of quantification were in the range of 1.9-75.1 g kg^-1 and 5.7-25.3 g kg^-1, respectively. Moreover, the total pretreatment and detection time was within 30 min. This method proved to be a promising alternative to other high-cost and time-consuming and multi-stage procedures for determination of PBDEs in vegetables.

Occurrence and distribution of organic ultraviolet absorbents in soils and plants from a typical industrial area in South China

Organic ultraviolet absorbents (UVAs) have attracted increasing concern due to their ubiquity, bioaccumulation, and potential toxicity. However, available information on their occurrence and transfer in terrestrial environment is still extremely insufficient. In this study, we investigated twelve UVAs in the soils and five terrestrial plant species from a typical industrial area in South China, and found their total concentrations were 5.87-76.1 (median 13.1) and 17.9-269 (median 82.9) ng/g dry weight, respectively. Homosalate was dominant in soils while benzophenone and octrizole were predominant in plants, likely due to their complex sources and bioaccumulation preferences. The bioaccumulation factors (BAFs) were further evaluated based on the ratios of UVA concentrations in plants and soils. The observed BAFs of UVAs were compound and species-specific, and most of them were much >1.0, indicating the chemicals could be transferred from soils to plants. To the best of our knowledge, this is the first report of organic UVAs in field soil-plant systems, providing information that may improve our understanding of the bioaccumulability of these chemicals in terrestrial environment and the associated risks. More studies are needed to investigate the transfer and bioaccumulation of such chemicals in soils and terrestrial biota.

A Pilot Study on the Concentration, Distribution and Bioaccumulation of Polybrominated Diphenyl Ethers (PBDEs) in Tissues and Organs of Grassland Sheep

Polybrominated diphenyl ether (PBDE) concentrations in various tissues and organs of grassland sheep from Inner Mongolia, China, were determined. The abilities of PBDEs binding to ovine serum albumin (OSA) and Cytochrome P450 enzyme (CYP3A24) were assessed by fluorescence spectroscopy and molecular docking simulations. The PBDE concentrations in the sheep tissue and organ samples were 33.4-167 pg/g dw. The distribution of PBDEs in sheep organs and tissues is affected not only by the function of organs and tissues, but also by the characteristics of PBDEs. Adipose tissue tends to bioaccumulate more-brominated BDEs (BDE-154, -153, and -183), but muscle tissues and visceral organs mainly bioaccumulate less-brominated BDEs. The distribution of PBDEs in visceral organs is mainly affected by the transport of ovine serum albumin (OSA) and the metabolism of CYP3A24 enzyme. The distribution of PBDEs in adipose tissue and brain is mainly affected by their logK_OW.

TFEB ameliorates autophagy flux disturbance induced by PBDE-47 via up-regulating autophagy-lysosome fusion

2,2',4,4'-tetrabromodiphenyl ether (PBDE-47), the widely used brominated flame retardant, has remarkable neurotoxicity which is associated with autophagy disorder. However, the mechanism remains unclear. The results showed that PBDE-47 damaged lysosomal biogenesis and interfered with autophagy-lysosome fusion both in vivo and in vitro. Our investigation further demonstrated that PBDE-47 could downregulate TFEB expression and inhibit the nuclear translocation of TFEB. Knockdown of TFEB in PC12 cells increased the reduction of lysosomal-associated proteins and the expression of STX17-SNAP29-VAMP8 proteins involved in autophagy-lysosomal fusion. Conversely, Overexpression TFEB in vitro significantly improved lysosomal abundance and ameliorated the autophagosome-lysosome fusion inhibition, thus restoring autophagic flux and improving PC12 cells survival. In addition, TFEB biologically interacted with STX17 by not inducing or inducing TFEB overexpression. Collectively, our results indicate that the autophagy flux compromised by PBDE-47 is related to the defective fusion of autophagosome and lysosome. TFEB may serve as a promising molecular target for future study of PBDE-47 developmental neurotoxicity.

Assessing the combinatorial cytotoxicity of the exogenous contamination with BDE-209, bisphenol A, and acrylamide via high-content analysis

Food is often exposed to multiple types of contaminants, and the coexistence of contaminants may have antagonistic, additive or synergistic effects. This study investigated the combinatorial toxicity of the three most widespread exogenous contaminants, decabrominated diphenyl ether (BDE-209), bisphenol A (BPA), and acrylamide (ACR) to HepG2 cells. A mathematical model (Chou-Talalay) and high-content analysis (HCA) were used to probe the nature of the contaminants' interactions and their cytotoxicity mechanisms, respectively. The results highlighted that for the individual pollutants, the cytotoxicity order was BDE-209> BPA > ACR, and varying combinations of contaminants exhibited additive/synergistic effects. In general, combining multiple contaminants significantly increased intracellular reactive oxygen species (ROS), Ca²⁺ flux, DNA damage and Caspase-3, and decreased mitochondrial membrane potential (MMP) and nucleus roundness, indicating that the additive or synergistic mechanism of the combined contaminations was disturbance to multiple organelles. This study emphasizes the complexity of human exposure to food contaminants and provides a scientific basis for formulating strict regulatory standards.

Curcumin hinders PBDE-47-induced neutrophil extracellular traps release via Nrf2-associated ROS inhibition

Polybrominated diphenyl ethers (PBDE-47), a kind of lipophilic persistent organic pollutants (POPs) brominated flame retardant, has been widely used in various consumer products. However, the toxicity of PBDE-47 on human immune system has not been well elucidated. Neutrophil extracellular traps (NETs) contribute to the innate immune responses, and the release of NETs is recognized as the most important part of the extracellular killing mechanism. The aim of this study was to investigate the effect of PBDE-47 on NETs and its possible molecular mechanism, as well as the intervention effect of curcumin (Cur). In this study, the formation of PBDE-47-induced NETs was observed by fluorescence microscopy and scanning electron microscopy, and was also quantitatively detected by DNA dye SYTOX green. In addition, we used Cur and Nrf2 inhibitor ML385 to explore the role of reactive oxygen species (ROS), extracellular signal regulated kinase (ERK) and p38 signaling pathway in PBDE-47-induced reticular formation. We demonstrated that PBDE-47 could significantly induce the formation of NETs, and its molecular mechanism might be related to ROS burst. Cur reduced ROS and inhibited PBDE-47-induced NETs formation by interfering with Nrf2. In conclusion, this study revealed that Cur hindered PBDE-47-induced NETs via Nrf2-associated ROS inhibition, which enriched the cytotoxicity mechanism of PBDE-47, and provided a new clue for the development of Cur as an antagonist of PBDE-47-related immune injury.

AhR-mediated CYP1A1 and ROS overexpression are involved in hepatotoxicity of decabromodiphenyl ether (BDE-209)

Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants. They are constantly detected in terrestrial, ocean, and atmospheric systems, and it is of particular concern that these fat-soluble xenobiotics may have a negative impact on human health. This study aimed to evaluate the toxic effect and underlying mechanism of decabromodiphenyl ether (BDE-209) on human liver in a HepG2 cell model. The results showed that BDE-209 significantly induced HepG2 cells apoptosis, increased intracellular reactive oxygen species (ROS), disturbed [Ca ²⁺] homeostasis and mitochondrial membrane potential (MMP), and caused nuclear shrinkage and DNA double-strand breaks. BDE-209 also significantly decreased the activities of antioxidant parameters, superoxide dismutase (SOD), total antioxygenic capacity (T-AOC), glutathione (GSH), and total glutathione (T-GSH). The up-regulation of the Aryl hydrocarbon receptor (AhR)/cytochrome P4501A1 (CYP1A1) signaling pathway indicates that after long-term and high-dose exposure, BDE-209 may be a liver carcinogen. Interestingly, HepG2 cells attempt to metabolize BDE-209 through the Nrf2-mediated antioxidant pathway. These findings help elucidate the mechanisms of BDE-209-induced hepatotoxicity in humans.

Distribution characteristics, bioaccumulation and trophic transfer of heavy metals in the food web of grassland ecosystems

In this study, according to the classification of biological "classes" and the different trophic levels of the food web, the distribution characteristics, bioaccumulation of heavy metals (HMs) and their trophic transfer in the food web of typical grassland ecosystems were studied and predicted. The results indicated that the accumulation of toxic As was the highest in small mammals and reptiles, Cu was the highest in insects, and the micronutrient Zn in large mammals was higher than that in plants. The metal transfer factor (MTF) by plants at the first trophic level showed that Leymus chinensis had the best ability to absorb HMs from soil. The trophic transfer factor (TTF) of HMs in the second-trophic level insects, birds and some mammals were Zn > As > Cu > Ni > Pb > Co = Cr > Mn > V, in which, biomagnified on Zn, As, and Cu. Organisms at the third trophic level including birds, reptiles and some mammals had the strongest accumulation ability for Pb, V and As, and all were biomagnified. The biomagnification on As and Co of the fourth trophic level Siberian weasel was obviously higher than that of Dione's rat-snake, which had significant biomagnification effect on As by preying on Steppe toad-headed agama. The study showed that the bioaccumulation levels of HMs in organisms at different trophic levels varied significantly with species, prey, and organ type, but they all showed strong bioaccumulation capacity to toxic As, which indicated that As could produce certain toxic effects on animals in the food web through trophic transfer. In addition, organisms at low-trophic levels were more likely to biomagnify Zn, while organisms at high-trophic levels were more likely to biodilute Pb.