Mitochondrial dysfunctions elicited by solid waste leachates provide insights into mechanisms of leachates induced cell death and pathophysiological disorders

Alterations in viscera histoarchitecture and organosomatic index as biomarkers of toxicity induced by Aba-Eku and Olusosun solid waste landfill leachates in Rattus norvegicus

Solid waste disposal generates leachate, a mixture of deleterious chemical, physical and microbial contaminants, which poses risk to human and wildlife health. Leachate toxicity on relative organ weight and histopathology of important viscera in mammalian body is scarce. Leachate induced toxic effects on organosomatic indices and histopathology of vital mammalian organs were investigated. Wister rats were orally exposed to 1 - 25 % of raw and simulated leachates from Aba-Eku and Olusosun landfills for 30 days. At post-exposure, organosomatic index and histoarchitectural assessment of major viscera (heart, spleen, thymus and lungs) were conducted. The physico-chemical and organic compositions of the leachates were analysed using standard protocol. The tested leachates decreased weekly and terminal body weights, and altered organosomatic index of examined viscera in rats. The histoarchitecture of the investigated viscera revealed pathologies that ranged from mild to severe degeneration, cellular infiltration, haemorrhage, congestion, necrosis, disorganization of tissues and vacuolations. Others include increased histiocytes within the bronchial associated lymphoid, lymphoid depletions, haemosiderin deposits and apoptosis were observed in the examined viscera. Physico-chemical analysis of the leachates showed different concentrations of toxic metals, PAHs and PCBs that were higher than national and international permissible limits allowed in wastewaters. The physico-chemical compositions of the leachates are capable of eliciting the observed alterations in organosomatic indices and histopathological lesions in mammalian viscera. Xenobiotic components of the leachates possibly generated free radicals and/or directly disrupted the organ architectures. These findings suggest health risk to wildlife and human population exposed to emissions from waste landfills.

Cytotoxic and oxidative changes in individuals occupationally exposed to recyclable municipal solid waste

aste collectors are exposed to a wide variety of bacteria, endotoxins, fungi, allergens, particulate matter, irritating inhalants, and vehicle exhaust, making them more prone to development of chronic diseases. Although several studies described the impact of occupational exposure on the overall health of waste collectors, few investigations were conducted regarding cellular and molecular changes that may occur due to exposure. The aim of this study was to assess biomarkers of oxidative stress such as levels of reactive oxygen species (ROS), lipoperoxidation, total antioxidant capacity (TAC), apoptosis, butyrylcholinesterase (BChE) activity and mitochondrial function (MitoTrackerTM Green FM and MitoTrackerTM Red) using the peripheral blood from individuals occupationally exposed to recyclable solid waste in Southern Brazil. The study included 30 waste collectors and 30 control individuals, who did not perform activities with recognized exposure to biological and chemical substances. Waste collectors were found to exhibit in peripheral blood leukocytes (PBL) higher rates of apoptosis, increased production of ROS, and reduced mitochondrial membrane potential (MMP), associated with decreased total antioxidant capacity (TAC) and elevated activity of BChE in plasma. Therefore, evidence indicates that cytotoxicity, oxidative stress, and inflammatory responses may be involved in the multiplicity of adverse health outcomes related to contaminant exposure in waste collectors. It is thus necessary to implement and/or improve occupational health programs aimed at workers as well as mandatory inspections for the use of personal protective equipment.

Mitochondrial dysfunction and endoplasmic reticulum stress induced by activation of PPARα leaded testicular to apoptosis in SD rats explored to di-(2-ethylhexyl) phthalate (DEHP)

Di-2-ethylhexyl phthalate (DEHP), as a common endocrine disrupting chemicals, can induce toxicity to reproductive system. However, the mechanism remains to be explored. In our study, DEHP exposure induced testicular injury in rats. The high throughput transcriptional sequencing was performed to identify differentially expressed genes (DEGs) between the treatment and control groups. KEGG analysis revealed that DEGs were enriched in apoptosis, PPARα, and ER stress pathway. DEHP up-regulated the expression of PPARα, Bax, Bim, caspase-4. GRP78, PERK, p-PERK, eIF2α, p-eIF2α, ATF4 and CHOP. This view has also been confirmed in TM3 and TM4 cells. In vitro, after pre-treatment with GW6471 (an inhibitor of PPARα) or GSK (an inhibitor of PERK), the apoptosis was inhibited and mitochondrial dysfunction was improved. Moreover, the improvement of mitochondrial dysfunction decreased the expression of PERK pathway by using SS-31(a protective agent for mitochondrial function). Interestingly, ER stress promoted the accumulation of ROS by ERO1L (the downstream of CHOP during ER stress), and the ROS further aggravated the ER stress, thus forming a feedback loop during the apoptosis. In this process, a vicious cycle consisting of PERK, eIF2α, ATF4, CHOP, ERO1L, ROS was involved. Taken together, our results suggested that mitochondrial dysfunction and ER stress-ROS feedback loop caused by PPARα activation played a crucial role in DEHP-induced apoptosis. This work provides insight into the mechanism of DEHP-induced reproductive toxicity.

Application of common industrial solid waste in water treatment: a review

Industrial solid waste has a wide range of impacts, and it is directly or indirectly related to land, atmosphere, water, and other resources. Industrial solid waste has a large amount of production, complex and diverse components and contains a variety of harmful substances. However, as industrial by-products, it also has a lot of available value. Industrial solid waste has been continuously studied in water treatment due to its special composition and porous and loose structure. It is known that there are few reviews of various industrial solid wastes in the field of wastewater treatment, and most of them only discuss single industrial solid waste. This paper aims to sort out the different studies on various solid wastes such as fly ash, red mud, wastewater sludge, blast furnace slag and steel slag in dyeing, heavy metal, and phosphorus-containing wastewater. Based on the modification of industrial solid waste and the preparation of composite materials, adsorbents, coagulants, catalysts, filtration membranes, geological polymers, and other materials with high adsorption properties for pollutants in wastewater were formed; the prospect and development of these materials in the field of wastewater were discussed, which provides some ideas for the mutual balance of environment and society. Meanwhile, some limitations of solid waste applications for wastewater treatment have been put forward, such as a lack of further researches about environment-friendly modification methods, application costs, the heavy metal leaching, and toxicity assessment of industrial solid waste.

The hazardous impact of true-to-life PET nanoplastics in Drosophila

Plastic pollution is a continuously growing problem that can threaten wildlife and human beings. Environmental plastic waste is degraded into small particles termed micro/ nanoplastics (MNPLs) that, due to their small size, can be easily internalized into the exposed organisms, increasing the risks associated with their exposure. To appropriately determine the associated health risk, it is essential to obtain/test representative MNPLs' environmental samples. To such end, we have obtained NPLs resulting from sanding commercial water polyethylene terephthalate (PET) bottles. These true-to-life PETNPLs were extensively characterized, and their potential hazard impacts were explored using Drosophila melanogaster. To highlight the internalization through the digestive tract and the whole body, transmission electron microscopy (TEM) and confocal microscopy were used. In spite of the observed efficient uptake of PETNPLs into symbiotic bacteria, enterocytes, and hemocytes, the exposure failed to reduce flies' survival rates. Nevertheless, PETNPLs exposure disturbed the expression of stress, antioxidant, and DNA repair genes, as well as in those genes involved in the response to physical intestinal damage. Importantly, both oxidative stress and DNA damage induction were markedly increased as a consequence of the exposure to PETNPLs.