Free and bound phenolics, antioxidant capacity and anthocyanins content of five elite blue maize hybrids and two native blue varieties grown in Mexico highlands were evaluated. Phenolic content of free and bound fractions was found from 1037 to 1488 and from 9064 to 11,987 mg gallic acid/kg, respectively. The free phenolic fraction of hybrid maize showed 3.7-fold higher hydrophilic antioxidant capacity than landrace counterparts. The highest anthocyanin content was found in hybrid 503 × 67 (1052 mg Cy3Glu/kg), which represented 73.1% of the free phenolics. Results indicated that elite blue maize hybrids could be an important source of antioxidant compounds with potential for either food or nutraceutical industries.

A pesticide characterization is presented for two highly technified valleys in northwest Mexico: Culiacan Valley (CV) in Sinaloa and Yaqui Valley (YV) in Sonora. Approximately 250,000 kg of active ingredients are used every year, half of which are considered highly hazardous pesticides. Legacy pesticides are still present in the soils of these valleys. The aim of the present study was to identify and quantify a wide variety of pesticides in soils and correlate their concentrations with historical and current use. Agricultural soils from both valleys were sampled and analyzed using accelerated solvent extraction and subsequent quantification by gas chromatography with selective detectors. The most frequently detected pesticides (mean, µg g⁻¹) in CV were organochlorines (0.1967), organophosphates (0.0928), synthetic pyrethroids (0.2565), organonitrogen (0.0552), and miscellaneous pesticides (0.1851). In YV, the most frequently detected pesticides were organochlorines (0.8607), organophosphates (0.0001), synthetic pyrethroids (0.0124), and miscellaneous pesticides (0.0009). The pesticides were more diverse in CV compared to those of YV, which was based on the types of crops produced. Both locations presented highly hazardous pesticides, including concentrations above the action levels established by the Canadian Soil Quality Guide. A follow-up risk assessment is recommended to assess potential effects.

Objective: In developing countries, rural communities often face the lack of potable water infrastructure and must rely on untreated sources for drinking, which are often contaminated with waterborne pathogens. The use of home water treatment devices is seen as one means of reducing the risk of exposure to waterborne pathogens. The aim of this study was to evaluate the microbiological and physicochemical performance of a simple in-home point-of-use device based on gravity ultrafiltration through an ultrafilter membrane. Methods: Twenty-five randomly selected households from 2 rural communities in Culiacán, Mexico, were enrolled. Water samples were collected before and after treatment and during storage for a period of 8 weeks. Heterotrophic bacteria, total coliforms, fecal coliforms, Escherichia coli, and Giardia spp were quantified, as well as various physicochemical parameters. Results: All of the untreated water samples contained high levels of indicator bacteria, but none were detected in the treated water fulfilling the requirements set by the Mexican Norm (NOM-127-SSA1-1994) and the World Health Organization guidelines for drinking water. However, indicator bacteria (fecal coliforms and E coli) were detected in every sample from water stored 24 hours after treatment. Conclusion: This study demonstrated that point-of-use filters using gravity-fed ultrafilters are a low-cost, effective water treatment technology for water of poor microbial quality. However, further identification of the sources and mechanisms by which water is contaminated when stored after treatment will help with designing and implementing better strategies for keeping water safe for domestic use.

A multi-residue method was developed to determine different types of pesticides in soils. An extraction with pressure and temperature, through accelerated solvent extraction (dichloromethane:acetone, 50:50, v/v). The pesticides were determined by gas chromatography with several selective detectors: electron capture detector, pulsed flame photometric detector and thermionic specific detector. The following parameters were determined: limit of detection, limit of quantification, equipment linearity (working interval), method linearity as well as, method accuracy and precision. The average recoveries ranged between 76 and 106%, with the exception of chlorothalonil, which had an average recovery of 46%. Additionally, detection limits from 0.9 to 7.6ng g⁻¹ and the quantification limits from 3.00 to 25.47ng g⁻¹ were estimated. In terms of linearity and precision, the results obtained were in the ranges considered adequate (R² ≥ 0.98 and coefficient of variation (CV) ≤ 20%), with the exception of aldrin (R² = 0.946, CV = 35.79%), lindane (R² = 0.917, CV = 32.91%) and chlorothalonil (R² = 0.8184, CV = 81.35%). The proposed method was used to evaluate pesticides in real soil samples, detecting concentrations over 1000ng g⁻¹ for some pesticides. The method was correctly validated and provided for the rapid determination of pesticides in soil.