Airborne particulate matter (PM) contains a large number of genotoxic substances capable of endangering human health. In the present study, we have investigated the ability of chemically characterized water-soluble and organic-soluble fractions of two particle sizes (PM2.5 and PM10) from different regions of Mexico City to induce DNA damage in a human lung epithelial cell line. We also evaluated associations between the physicochemical parameters of the PM and its genotoxicity. The airborne particulate samples were collected from four regions of the city; a HiVol air sampler was used to collect PM10 on glass fiber filters and a tapered element oscillating system coupled to an automatic cartridge collection unit was used to collect PM2.5 on teflon filters. PM mass was determined by gravimetric analysis of the filters. Filters containing PM2.5 and one section of each PM10 filter were agitated either with deionized water to extract water-soluble compound, or with dichloromethane to prepare organic-soluble compounds. The chemical composition of the extracts was determined by ion and gas chromatography and atomic adsorption spectroscopy. A549 human type II alveolar epithelial cells were exposed to different concentrations of the PM2.5 and PM10 extracts, and alkaline single cell gel electrophoresis or the Comet assay was performed to measure DNA damage and repair. These analyses indicated that soluble transition metals and the organic-soluble PM fractions are crucial factors in the DNA damage induced by PM. PM composition was more important than PM mass for producing genotoxicity. The results of this study showed that the constituents of the water-soluble PM extract are more likely to induce DNA damage than the organic compounds.

Several studies have suggested that human semen quality has declined over the past decades and some of them have associated it with occupational exposure to pesticides. However, most of these studies have not been associated with a reliable exposure level and have been designed mostly as cross-sectional studies. The present work evaluates, in a longitudinal follow-up study, the effect of organophosphate pesticides (OP) at three occupational exposure levels on semen quality. In addition, the study examined the association between OP urinary levels and sperm parameters in exposed and unexposed workers. A total of 139 semen samples from 52 volunteers were assessed. Urinary OP levels were measured by gas-liquid chromatography. The results revealed that the poorest semen quality was found among the subjects with the highest OP exposure and the highest urinary OP levels. Seasonal variations in sperm concentration and sperm count were registered. The results showed a significant decrease in total sperm count among subjects with the highest exposure to OP. Further studies assessing the effects of OP on male reproductive health should be controlled by the variability in human sperm parameters, sperm seasonality, spermatogenesis time and the changing OP exposure level in men highly exposed to OP.

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Background: Breast cancer (BC) is the primary cause of cancer deaths among women in Mexico. Our previous work has shown associations between BC and arsenic (As) and phthalate exposure, respectively, in Mexican women.Objectives: To explore whether environmental exposure to As and phthalates interact in their association with BC.Methods: A total of 233 cases with incident BC and 221 controls (matched to cases by age and state) were recruited as part of an ongoing case-control study in 5 states in northern Mexico. Reproductive history, sociodemographic, and anthropometric data were collected using questionnaires and physical measurements. Concentrations of creatinine, 9 phthalate metabolites, and speciated As were measured from first-morning void samples. As methylation capacity was assessed by the primary (PMI) and secondary (SMI) methylation indices: [monomethylarsonic acid]/[As(III)+As(V)] and [dimethylarsinic acid/monomethylarsonic acid], respectively. Logistic regression was used to estimate odds ratios comparing high (> median) to low (≤ median) levels of phthalate metabolites and indices of As methylation capacity (IAMC). Likelihood ratio tests were used to test for interaction.Results: Statistically significant (p<0.20) sub-multiplicative interaction in the association with BC was identified for the following exposures: 1) the PMI and mono-(3-carboxypropyl) phthalate, 2) the PMI and mono-(2-ethyl-5-hydroxyhexyl) phthalate, and 3) the SMI and monobenzyl phthalate.Conclusions: Biological data are necessary to determine whether these findings are related to a common pathway in the metabolism of these exposures that alters BC risk.