Occupational exposure to polychlorinated biphenyls (PCBs) in workers at companies in the Colombian electricity sector

A comprehensive review of toxicity of coal fly ash and its leachate in the ecosystem

Coal fly ash (CFA), a byproduct of coal combustion, is a hazardous industrial solid waste. Its excessive global production, coupled with improper disposal practices, insufficient utilization and limited awareness of its inherent hazards, poses a significant threat to both ecological environment and human health. Based on the physicochemical properties of CFA and its leachates, we elucidate the forms of CFA and potential pathways for its entry into the human body, as well as the leaching behavior, maximum tolerance and biological half-life of toxic elements present in CFA. Furthermore, we provide an overview of current strategies and methods for mitigating the leaching of these harmful elements from CFA. Moreover, we systemically summarize toxic effect of CFA on organisms across various tiers of complexity, analyze epidemiological findings concerning the human health implications resulting from CFA exposure, and delve into the biotoxicological mechanisms of CFA and its leachates at cellular and molecular levels. This review aims to enhance understanding of the potential toxicity of CFA, thereby promoting increased public awareness regarding the disposal and management of this industrial waste.

Resveratrol ameliorates ortho- polychlorinated biphenyls' induced toxicity in ovary cells

Polychlorinated biphenyls (PCBs) can induce chronic oxidative stress, inflammation, and cell death, leading to coronary heart disease, endothelial dysfunction, neurotoxicity, cancer, obesity, type 2 diabetes, reproductive dysfunction, etc. The aim of this study was to investigate possible protective effect of resveratrol (2.5-20 μM) in ovarian cells exposed to PCBs. An emphasis was on identifying mechanisms of resveratrol action upon distinct structure of the individual PCB congener-planar dioxin-like PCB 77 and non-planar di-ortho-substituted PCB 153. Multiple toxicity endpoint analysis was performed. Cell viability/proliferation was assessed by Trypan Blue exclusion method, Neutral Red, Kenacid Blue, and MTT bioassays. The level of oxidative stress was measured by fluorescent probes, and flow cytometry was applied to evaluate the mode of cell death. Resveratrol applied alone did not affect cell proliferation and viability in doses up to 20 µM, although significant antioxidative activity was observed. Toxic effects of ortho-PCB 153 (cytotoxicity, oxidative stress, and cell death) were mitigated by resveratrol. On the contrary pre-incubation with resveratrol did not result in cell viability protection when planar PCB 77 was applied. This indicates that resveratrol efficacy may be linked to specific structure of the individual congener, suggesting nutritional modulation of environmental insults caused by ortho-PCBs. We point out the importance of resveratrol dosage considering that synergistic cytotoxic effect with both PCB congeners is observed at concentrations ≥ 10 μM.

Human Biomonitoring of Polychlorinated Biphenyls (PCBs) in the Breast Milk of Colombian Mothers

Polychlorinated biphenyls (PCBs) are persistent in the environment, bioaccumulate and biomagnify throughout the food chain, and may have adverse effects on human health and wildlife. PCB indicator (PCB 28, PCB 52, PCB 101, PCB 118, PCB 138, PCB 153, and PCB 180) were monitored in human milk using 68 samples from healthy and primiparous mothers from seven cities in Colombia, and the estimated daily intake (EDI) of infants was calculated. The PCB indicator with the highest concentration was PCB 153 with a value of 7.30 ng g^-1 lipids. The maximum EDI was calculated as 0.257 μg kg^-1 bw^-1 day^-1. In general, the PCB levels found in the 68 samples were low and did not represent a risk to breastfed infants. Additionally, these results could strengthen Colombia's efforts to increase the practice of breastfeeding. Finally, the results establish a general overview of population exposure and can be a scientific tool to improve environmental health policies in the country.