Cytogenetic biomonitoring of inhabitants of a large uranium mineralization area: the municipalities of Monte Alegre, Prainha, and Alenquer, in the State of Pará, Brazil.
Uranium is a natural radioactive metallic element; its effect on the organism is cumulative, and chronic exposure to this element can induce carcinogenesis. Three cities of the Amazon region-Monte Alegre, Prainha, and Alenquer-in North Brazil, are located in one of the largest uranium mineralization areas of the world. Radon is a radioactive gas, part of uranium decay series and readily diffuses through rock. In Monte Alegre, most of the houses are built of rocks removed from the Earth's crust in the forest, where the uranium reserves lie. The objective of the present work is to determine the presence or absence of genotoxicity and risk of carcinogenesis induced by natural exposure to uranium and radon in the populations of these three cities. The frequency of micronuclei (MN) and chromosomal aberrations (CA) showed no statistically significant differences between the control population and the three study populations (P > 0.05). MN was also analyzed using the fluorescence in situ hybridization (FISH) technique, with a centromere-specific probe. No clastogenic and/or aneugenic effects were found in the populations. Using FISH analysis, other carcinogenesis biomarkers were analyzed, but neither the presence of the IGH/BCL2 translocation nor an amplification of the MYC gene and 22q21 region was detected. Clastogenicity and DNA damage were also not found in the populations analyzed using the alkaline comet assay. The mitotic index showed no cytotoxicity in the analyzed individuals' lymphocytes. Once we do not have data concerning radiation doses from other sources, such as cosmic rays, potassium, thorium, or anthropogenic sources, it is hard to determine if uranium emissions in this geographic region where our study population lives are too low to cause significant DNA damage. Regardless, genetic analyses suggest that the radiation in our study area is not high enough to induce DNA alterations or to interfere with mitotic apparatus formation. It is also possible that damages caused by radiation doses undergo cellular repair.
Guimarães
Adriana Costa
AC
Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil.
Antunes
Lusânia Maria Greggi
LM
Ribeiro
Helem Ferreira
HF
dos Santos
Andrea Kelly Ribeiro
AK
Cardoso
Plínio Cerqueira dos Santos
PC
de Lima
Patrícia Lima
PL
Seabra
Aline Damasceno
AD
Pontes
Thaís Brilhante
TB
Pessoa
Claudia
C
de Moraes
Manoel Odorico
MO
Cavalcanti
Bruno Coelho
BC
Sombra
Carla Maria Lima
CM
Bahia
Marcelo de Oliveira
Mde O
Burbano
Rommel Rodríguez
RR
D024422:Aneugens; D001938:Brazil; D002274:Carcinogens, Environmental; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D019457:Chromosome Breakage; D020090:Chromosome Segregation; D020552:Comet Assay; D004249:DNA Damage; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008214:Lymphocytes; D015162:Micronucleus Tests; D008906:Mining; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity; D011829:Radiation Dosage; D011848:Radioactive Pollutants / Q000032:analysis; D011886:Radon / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis; D011795:Surveys and Questionnaires; D014501:Uranium / Q000633:toxicity*
D024422:Aneugens; D002274:Carcinogens, Environmental; D009153:Mutagens; D011848:Radioactive Pollutants; D012989:Soil Pollutants; D014501:Uranium; D011886:Radon