(ORDO NEWS) — Polish researchers have demonstrated for the first time how three pure nitrophenols – or a mixture of them, which is also formed during the preparation of barbecue – affect human lung cells.
Employees of the Institute of Physical Chemistry at the Polish Academy of Sciences, in collaboration with the US Environmental Protection Agency, studied the effect of nitrophenols – organic and at the same time carcinogenic compounds in the air – on human health.
Mononitrophenols affect the central nervous system, kidneys and liver, dinitrophenols irritate the mucous membranes and skin, leading to dermatitis.
They are toxic not only to mammals, but also to plants. 4-nitrophenol has a slow interaction with the blood and forms methemoglobin, an iron oxidation product in the hemoglobin molecule, which is responsible for methemoglobinemia: this can cause cyanosis, confusion and loss of consciousness.
Nitrophenols are exposed to the lungs by inhalation of PM2.5 microparticles containing them, and the risk is especially increased in industrial and urban environments, as well as in regions with high levels of emissions from biomass combustion.
Barbecuing (barbecue in Western countries), car exhaust , burning wood or grass in the field – all these and other activities increase the content of nitrogen oxides and dust in the atmosphere, which turn into carcinogenic compounds under sunlight.
The aim of the new study, published in the journal Environmental Pollution , was to study for the first time the effects of pure nitrophenols and their mixture on human lung cells.
“We have qualitatively identified three nitrophenols in PM2.5 microparticles collected from several sites in the United States and in secondary organic aerosol (SOA) particles formed from the photooxidation of aromatic hydrocarbons (benzene, toluene, o- xylene, m -xylene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, ethylbenzene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene and benzyl alcohol).
The study was conducted in EPA smog chambers and in the presence of nitrogen oxides, ”the scientists write.
The mixture of compounds and particles that were placed in the chamber underwent chemical reactions under solar radiation, which led to the conversion of nitrogen oxides into nitrophenols.
Also, the authors of the article conducted in vitro studies and revealed early changes in lung cells: nitrophenolsexhibited various inhibitory and cytotoxic effects. Individually, 4-nitrophenol was the most cytotoxic, and 2-nitrophenol was the least.
“When exposed to 4-nitrophenol, cellular inhibition occurred within the first 24 hours, followed by increased cell death between 24 and 48 hours.
The accumulation of reactive oxygen species (ROS) led to cell death after exposure to 3-nitrophenol, 4-nitrophenol and mixtures of these compounds, while 2-nitrophenol induced the lowest ROS accumulation,” the researchers explained.
In other words, cells that survived exposure to these organic compounds showed destruction of the mitochondrial membrane, which acts as a natural barrier.
As a result, nitrophenols quickly entered the cell itself and provoked apoptosis , and then necrosis. The most dangerous were high concentrations of compounds – such are observed, for example, in conditions of smog and forest fires.
“Dysmorphic mitochondria are associated with chronic respiratory diseases, including asthma, allergies, bronchitis, and pulmonary hypertension. Thus, the consequences of exposure to nitrophenols at the level of suborganelles may indicate disturbances in the functioning of mitochondrial membranes,” the scientists concluded.
Contact us: [email protected]