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Thiamethoxam is a neonicotinoid with systemic and contact action, used in Mexico for the care of different traditional fruit crops, mainly in the cultivation of papaya. Soils of agroecosystems with papaya in the Gulf of Mexico area, the main producers of this fruit, are currently characterized as 45% of the producers organize papaya cultivation in rotation with watermelon at different sowing dates. The objective of this study was to determine the presence and concentration of thiamethoxam in soil and water during the rotation of papaya crop with watermelon culture in the central zone of Veracruz, Mexico. An analysis was carried out to know the management of thiamethoxam in different types of soil and in the region; and in an experimental plot. Soil and water samples were taken at different stages during the rotation of both crops. Those samples were taken systemically, starting with the watermelon culture cycle and then, during the phenological stages in the papaya crop cycle. Soil and water samples were analyzed using HPLC-UV equipment for its determination. The design was random blocks with six repetitions and the software used for data analysis was the Statistica 2007 program. Thiamethoxam was concentrated in amounts of ≥0.40 mg/L in 79% of the samples in water and ≥0.55 mg/kg in 75% of the samples in soil. The highest values of thiamethoxam in soil were in the stage of watermelon culture with 0.4 mg/kg and in the soil preparation of the papaya crop with concentrations of 0.8 mg/kg. Whereas irrigation water from the watermelon cultivation and the soil preparation for the papaya showed concentrations of 0.5 and 0.7 mg/L, respectively. The presence of thiamethoxam was identified in 100% of the samples analyzed in the stage of preparation of soil and water of the cultivation area, concluding a possible risk of residuality of thiamethoxam in fruits that exceed the maximum limits of tolerance established by the EPA, EFSA and FAO.

Objective: To know the variables of the reproductive component of materials for manual cross-pollination purposes, for which the search for sexual synchrony is emphasized. Design/methodology/approach: Four materials were analyzed, two with white pulp and two with red pulp, about which it is unknown if they present sexual self-incompatibility, and the synchrony in flowering is also unknown. The flowering phase and the variables that can shed light on its reproductive behavior were analyzed Results: It was found that the red materials present strong hercogamy, they cannot self-fertilize. There is also no floral synchrony, but there is closeness between the date of anthesis in a pitahaya with white pulp and a red one, which would allow promoting cross-pollination. Study limitations/implications: Hylocereus spp. is consumed in a large part of the world and has acquired a very strong importance since the industrial demand is increasing; however, several of the genotypes used in commercial production in Mexico show low fruit set compared to high floral emission, which is considered self-incompatibility. Findings/conclusions: The presence of hercogamy, stronger in the red-fleshed materials, indicates the existence of sexual self-incompatibility, explaining the fact that the materials emit a large number of flowers, but do not achieve fruit setting. [ABSTRACT FROM AUTHOR]

The objective of the research was through key actors to identify the contamination by hydrocarbons and heavy metals in water and the main sources of contamination in the municipality of Macuspana, Tabasco. Methodology: A diagnosis was made, by applying questionnaires through interviews directed to the inhabitants of the municipality of Macuspana and workers in the oil sector. The data were processed with frequency analysis, Kruskal Wallis, analysis of variance, and multivariate with two factors. Results: It was shown that there has been historical contamination, for 30 years, there is evidence of dead organisms in the water bodies, and the presence of various diseases in the population due to exposure to contaminants from hydrocarbons and heavy metals that derive from the oil activity. There is evidence of a negative impact due to the presence of spills from disabled wells due to a lack of maintenance programs. Implications: The economy in most of the Gulf of Mexico is based on the extraction, processing, and distribution of hydrocarbons. This industry´s growth increased the number of exploration and production of oil wells, generating a direct impact on aquatic environments. The state of Tabasco is one of the largest oil producers, as well as fishing resources of commercial and environmental importance, which are directly affected by oil activity. Findings: The study found cases of diseases in the population correlated with exposure to hydrocarbons. Conclusions: There is little interest from the oil sector about public health problems in the population and environmental damage to the ecosystems in the municipality of Macuspana, Tabasco. [ABSTRACT FROM AUTHOR]