Assessment of exposure to mixture pollutants in Mexican indigenous children.

The aim of the present work was to complete an exposure assessment in three Mexican indigenous communities using the community-based health risk assessment, which is the first step in the CHILD framework. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to polycyclic aromatic hydrocarbons (PAHs) and trans, trans-muconic acid (t,t-MA) as an exposure biomarker to benzene, persistent organic pollutants (POPs), lead, manganese, arsenic, and fluoride. Anthropometric measurements were also taken. In these communities, high percentages of children with chronic malnutrition were found (28 to 49 %) based on their weight and age. All communities showed a high percentage of children with detectable levels of four or more compounds (70 to 82 %). Additionally, our results showed that in indigenous communities, children are exposed to elevated levels of certain environmental pollutants, including manganese with 17.6, 16.8, and 7.3 µg/L from SMP, TOC, and CUA, respectively. Lead and HCB levels were similar in the indigenous communities (2.5, 3.1, and 4.2 µg/dL and 2.5, 3.1, and 3.7 ng/mL, respectively). 1-OHP and t,t-MA levels were higher in TOC (0.8 µmol/mol of creatinine, 476 µg/g of creatinine, respectively) when compared with SMP (0.1 µmol/mol of creatinine, 215.5 µg/g of creatinine, respectively) and CUA (0.1 µmol/mol of creatinine, 185.2 µg/g of creatinine, respectively). DDE levels were 30.7, 26.9, and 9.6 ng/mL in CUA, SMP, and TOC, respectively. The strength of this study is that it assesses exposure to pollutants with indications for the resultant risk before an intervention is made by the CHILD program to manage this risk in the indigenous communities. Considering the large number of people, especially children, exposed to multiple pollutants, it is important to design effective intervention programs that reduce exposure and the resultant risk in the numerous indigenous communities in Mexico.

Development and validation of an analytical method to determine Fipronil and its degradation products in soil samples.

The aim of this study was to develop a methodology for identifying and quantifying Fipronil and its degradation products in soil by gas chromatography-electron capture detector previously extracted using a focused ultrasound probe. This methodology was obtaining a range of recovery between 85% and 120%, decreasing approximately solvent used time and cost, respect to other methodologies such as bath ultrasonic, solid-phase extraction, liquid-liquid extraction and soxhlet. The method was validated in fortified matrix, presented linearity in the range of 25-400 µg kg(-1), and limit of detection for Fipronil and their products desulfinyl, sulfide and sulfone was 14.7, 9.8, 8.9 and 10.7 µg kg(-1), respectively. This process was applied to samples of agricultural soils, where two degradation products desulfinyl and sulfone were found.