**4. Conclusions**

The coal mining activities generate different types of compounds that are released into the environment. Once into the atmosphere, these compounds form a complex mixture that consists of metals, oxides, and PAHs. These compounds can interact with "acellular" and cellular mechanisms related with ROS production. The metals found in the coal fly ash and coal particles by different ways lead to the ROS formation. Important macromolecules as DNA, proteins, and lipids can suffer oxidative modifications. The PAHs contained in the particles also influence the particles toxicity. A second indirect way for excessive ROS formation is related to cellular mechanisms, which is consequence of oxidative burst of macrophages and neutrophils during phagocytosis of particles and inflammation produced.

If we think in exposed populations, we cannot ignore the social and environmental impact associated with coal mining. The continuous inhalation, the high load of particles in phagocytic cells, the oxidant-antioxidant imbalance which are linked to the origin of pathological processes; this whole scenario is worrisome to biologic level for these populations. In addition, in recent years, coal mining had a remarkable increase in demand; international mining companies have increased their investments in exploration around the world. For this reason, human biomonitoring studies in exposed populations become really necessary to contribute to knowledge state about the risk for those people in order to motivate the design of control, hygiene, and prevention strategies, besides epidemiological surveillance.

## **Author details**

Grethel León-Mejía 1,2, Milton Quintana Sosa 2 , Paula Rohr 3 , Katia Kvitko4 , João Antonio Pêgas Henriques 1,5\* and Juliana da Silva 6\*

\*Address all correspondence to: pegas.henriques@gmail.com and juliana.silva@ulbra.br

1 Laboratory of Molecular Radiobiology, Center of Biotechnology, Postgraduate Program in Cell and Molecular Biology (PPGBCM), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil

2 Simon Bolivar University, Faculty of Basic Sciences, Unit of Research, Development and Innovation in Genetics and Molecular Biology, Barranquilla, Colombia

3 Laboratory of Celular and Molecular Biology, Academic Unit of Health Sciences, Universi‐ dade do Extremo Sul Catarinense (UNESC) – Criciúma SC), Brazil

4 Postgraduate Program in Genetics and Molecular Biology (PPGBM), Federal University of Rio Grande do Sul (UFRGS) Porto Alegre, Rio Grande do Sul, Brazil

5 Laboratory of Molecular Radiobiology, Center of Biotechnology, Federal University of Rio Grande do Sul (UFRGS) Porto Alegre, Rio Grande do Sul, Brazil

6 Laboratory of Genetic Toxicology, Postgraduate Program in Molecular and Cell Biology Applied to Health (PPGBioSaúde), Lutheran University of Brazil (ULBRA), Canoas, Rio Grande do Sul, Brazil
