Aflatoxins Contamination in Maize Products from Rural Communities in San Luis Potosi, Mexico.

BACKGROUND: Aflatoxins are a group of mycotoxins that have been associated with hepatic damage and cancer. Aflatoxins B1 and B2 are secondary metabolites produced by fungi Aspergillus. These toxins can be found in a variety of commodities, especially in maize, and have been studied around the world due to their effects in human health. The Latin American population is especially exposed to aflatoxins given that maize products can be found in traditional diets all over the continent. Interestingly, in Mexico, chronic hepatic diseases and cirrhosis are leading causes of death in adult population. METHODS: In order to observe the effect of physical variables like temperature and humidity, this study was conducted collecting samples in four different seasons, in two communities in the State of San Luis Potosi, in Mexico. The content of aflatoxins in tortillas was measured using immunoaffinity columns prior to HPLC-FLD analysis. FINDINGS: Results showed that 18% of samples exceeded the Mexican limits for AFB1; whereas, 26% of the samples exceeded the limits of the European Union for AFB1. The AFB1 was detected in 80% of samples in one site and higher concentrations were found in samples collected during fall and winter seasons. CONCLUSIONS: Lack of control in storing practices is the principal cause for the contamination of maize. Considering that maize products are part of the staple diet of Mexican population, our results show that AFB1 detection has to be declared a public health priority. Detection and prevention of aflatoxins through a surveillance program, may avoid chronic health effects.

Genotoxic and hematological effects in children exposed to a chemical mixture in a petrochemical area in Mexico.

Children living in Coatzacoalcos, Veracruz, and in nearby surrounding areas are exposed to a mixture of pollutants from different sources. Previous studies in the area have reported genotoxic and haematotoxic compounds, such as lead (Pb), benzene, toluene, and polycyclic aromatic hydrocarbons (PAHs), in environmental and biological samples. The final toxic effects of these compounds are unknown because the toxic behaviour of each compound is modified when in a complex mixture. This is the first study on the exposure and effect of chemical mixtures on children who live near a petrochemical area. The aim of this study was to evaluate genotoxicity and haematological effects in children environmentally exposed to such mixtures and to determine whether the final effect was modified by the composition of the mixture composition. Biomarkers of exposure to Pb, benzene, toluene, and PAHs were quantified in urine and blood samples of 102 children. DNA damage was evaluated using comet assay, and haematological parameters were determined. Our results show that Pb and toluene did not surpass the exposure guidelines; the exposure was similar in all three localities (Allenede, Mundo Nuevo, and López Mateos). In contrast, exposure to PAHs was observed at three levels of exposure: low, medium, and high. The most severe effects of these mixtures were strictly related to coexposure to high levels of PAHs.

Epigenetic markers of exposure to polycyclic aromatic hydrocarbons in Mexican brickmakers: a pilot study.

A pilot cross-sectional study was carried out in a group of 39 male brick manufacturers in San Luis Potosi, Mexico to identify epigenetic biomarkers of exposure to polycyclic aromatic hydrocarbons (PAHs). A questionnaire was used to compile the smoking and drinking habits, clinical history, working time, and socioeconomic characteristics of the participants. 1-Hydroxypyrene (1-OHP) levels were measured from urine samples using high-performance liquid chromatography, and genomic DNA was isolated from blood samples for methylation analysis using pyrosequencing. The mean 1-OHP level was 0.18 µg g(-1) creatinine (range 0.023-1.11), which was below the expected occupational exposure level. After adjusting for potential confounders, the 1-OHP urine concentration was negatively associated with DNA methylation of the interleukin 12 (ß=-1.57; 95% CI: -2.9 to -0.23; p=0.02) and p53 gene promoters (ß=-2.7; 95% CI: -5.46-0.06; p=0.055). Suggestive negative associations were also found for the TNF-α gene (ß=-3.9; 95% CI:-8.28-0.48; p=0.08) and Alu sequences (ß=-0.55; 95% CI:-1.25-0.16; p=0.12). Although the individual exposures to PAHs as estimated by urinary 1-OHP concentrations were low, changes in specific and global DNA methylation were observed.

Assessment of DDT, DDE, and 1-hydroxypyrene levels in blood and urine samples in children from Chiapas Mexico.

PURPOSE: The aim of this study was assess co-exposure to DDT, DDE (main DDT metabolite), and PAHs (1-hydroxypyrene) in areas where biomass is used to cook and to heat homes and where DDT was used to combat malaria transmission. METHODS: During 2009, we analyzed a total of 190 blood and urine samples from children living in six communities in Mexico. Quantitative analyses of DDT and DDE were performed using gas chromatography coupled with mass spectrometry. Analyses of 1-hydroxypyrene were performed by HPLC using a fluorescence detector. RESULTS: In this work, we found high levels of DDT and its principal metabolite (DDE) in the blood of children living in four communities in Chiapas located in the southeastern region of Mexico (range,

Assessment of the levels of DDT and its metabolites in soil and dust samples from Chiapas, Mexico.

The aim of this study was to assess the levels of DDT and its metabolites in two environmental matrices (soil and dust) in five communities in Chiapas, Mexico. DDT and its metabolites were analyzed by gas chromatography/mass spectrometry. The soil levels of total DDT ranged from non detectable (

Exposure of children to polycyclic aromatic hydrocarbons in Mexico: assessment of multiple sources.

PURPOSE: Biological monitoring of polycyclic aromatic hydrocarbons (PAHs) has expanded rapidly since urinary 1-hydroxypyrene (1-OHP) was suggested as a biological index for pyrene. Taking into account that pyrene is often present in PAHs mixtures, 1-OHP has also been considered an indirect indicator of exposure to these mixtures. Sources of PAHs in developing countries are numerous; however, exposure of children to PAHs has not been studied in detail. Therefore, the aim of this study was to assess exposure of children to PAHs in different scenarios: (a) children living next to highways with heavy traffic; (b) sanitary landfill; (c) brick kiln communities and (d) children exposed to biomass combustion. METHODS: A total of 258 children (aged 3-13) participated in the study. The analyses were performed by HPLC with fluorescence detector. Urinary 1-OHP concentrations were then adjusted by urinary creatinine. RESULTS: The highest levels of 1-OHP in this study were found in children exposed to biomass combustion (mean value 3.25 micromol/mol creatinine), but exposure was also detected in children living in communities with brick kiln industry (mean 0.35 micromol/mol creatinine), or in a community next to a sanitary landfill (with waste combustion) (0.30 micromol/mol creatinine) and in children exposed to traffic (mean value 0.2 micromol/mol creatinine and 0.08 micromol/mol creatinine). CONCLUSIONS: Considering our results and taking into account that millions of children in Mexico are living in scenarios similar to those studied in this work, the assessment of health effects in children exposed to PAHs is urgently needed; furthermore, PAHs have to be declared contaminants of concern at a national level.