Genotoxic Effects of Environmental Exposure to Arsenic and Lead on Children in Region Lagunera, Mexico

Abstract

DNA damage and DNA repair ability by means of the comet assay and the hydrogen peroxide challenge in lymphocytes from 65 children exposed simultaneously to As and Pb in Region Lagunera, Mexico. The first exposure scenario was concerned with natural As contamination in drinking water affecting all children, particularly those attending the schools farthest from (Gomez Palacio) and closest to the smelter (Pedro Garcia). The second scenario related to additional Pb and As soil and dust contamination in the schools located in the smelter vicinity (Heroe de Nacozari and Pedro Garcia). Most children (93%) had As in urine (AsU) above 50 microg/L and 65% had blood Pb (PbB) above 10 microg/dL. The highest AsU median levels were observed in the school farthest from the smelter, whereas the highest PbB values were observed in the closest school. DNA damage and a decreased repair ability observed in children attending the schools were more severe than those reported for healthy Mexican children. However, the multivariate analysis did not show significant associations between DNA basal damage and PbB or AsU. Lymphocytes from 58% of the children did not respond to the peroxide challenge, and those had a more severe basal DNA damage. DNA repair capacity showed a slowed response and was negatively associated with AsU. Thus, in addition to reduced exposure, further studies are needed to ascertain if the deficiency in DNA repair is transient or if children are already displaying a mutator phenotype and are at risk of developing cancer.

Association of blood lead levels with urinary F2-8α isoprostane and 8-hydroxy-2-deoxy-guanosine concentrations in first-grade Uruguayan children

“…To our knowledge, no studies in children examined the association between BLL and 8-OH-dG to compare with our findings. However, four studies in children examined the relation between BLL and DNA damage or DNA repair as measured by the comet assay (also known as single cell gel electrophoresis) or other methods (such as micronuclei (MN) and sister chromatid exchange (SCE) levels in peripheral lymphocytes) (Jasso-Piñeda et al, 2012, Mendez et al, 2008, Mielzynska et al, 2006; Yanez et al, 2003) and found higher levels of DNA damage in children with higher BLL compared to children with lower BLL. In addition, Mielzynska and colleagues (2006) observed a direct association between BLL and DNA damage as measured by number of micronuclei per 1000 cells in peripheral lymphocytes in 5–14 year old Polish children with a mean BLL of 7.7 μg/dL.…”

Assessment of Arsenic Induced DNA Fragmentation by using Comet Assay

“…DNA damage has been detected in ovarian tissue in a dose-dependent manner [29]. Similarly higher extent of DNA fragmentation has also been reported in different communities of San Luis Potosi State [37] and in different schools of Mexico [36] located at different distances from arsenic smelter area.…”

“…People of India (Murshidabad) exposed to arsenic contaminated drinking water express greater extent of DNA migration compared to unexposed population [35]. Mendez-Gomez et al [36] and Jasso-Pineda et al [37] studied different arsenic exposed areas in Mexico and observed greater fragmentation of DNA damage in areas located nearest to arsenic source (Table 2).…”

Association of glutathione S-transferase Ω 1-1 polymorphisms (A140D and E208K) with the expression of interleukin-8 (IL-8), transforming growth factor beta (TGF-β), and apoptotic protease-activating factor 1 (Apaf-1) in humans chronically exposed to arsenic in drinking water

“…This region has historically had high levels of As in drinking water (Del Razo et al 1990;Marnell et al 2003;Méndez-Gómez et al 2008). Arsenic concentrations in water used for drinking and cooking have been reported to fall within the range of 0.01-0.62 mg/l.…”