Browsing by Subject "pesticides"

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  • Fernandez Bravo, Sergio; Bertomeu Sánchez, José Ramón; Schifter Aceves, Liliana (2020)
    This work is a historic analysis of the use of dichloro-diphenyl-trichloroethane (DDT) in Mexico since the 1940s and its implications for the then nascent domestic agrochemical industry and the social development programs boosted by the Mexican State. DDT was introduced to Mexico at the beginning of that decade as one of the main technological inputs of the agrarian and health models designed by the Rockefeller Foundation, which identified both malaria and low agricultural production as critical problems for this country. The adoption of these models by the Mexican political and economic system encouraged the creation of public institutions and a national agrochemical industry as well, which allowed the persistent DDT use and production for more than 50 years in Mexico.
  • Harju, A. Vilhelmiina; Narhi, Ilkka; Mattsson, Marja; Kerminen, Kaisa; Kontro, Merja H. (2021)
    Views on the entry of organic pollutants into the organic matter (OM) decaying process are divergent, and in part poorly understood. To clarify these interactions, pesticide dissipation was monitored in organic and mineral soils not adapted to contaminants for 241 days; in groundwater sediment slurries adapted to pesticides for 399 days; and in their sterilized counterparts with and without peat (5%) or compost-peat-sand (CPS, 15%) mixture addition. The results showed that simazine, atrazine and terbuthylazine (not sediment slurries) were chemically dissipated in the organic soil, and peat or CPS-amended soils and sediment slurries, but not in the mineral soil or sediment slurries. Hexazinone was chemically dissipated best in the peat amended mineral soil and sediment slurries. In contrast, dichlobenil chemically dissipated in the mineral soil and sediment slurries. The dissipation product 2,6-dichlorobenzamide (BAM) concentrations were lowest in the mineral soil, while dissipation was generally poor regardless of plant-derived OM, only algal agar enhanced its chemical dissipation. Based on sterilized counterparts, only terbutryn appeared to be microbially degraded in the organic soil, i.e., chemical dissipation of pesticides would appear to be utmost important, and could be the first response in the natural cleansing capacity of the environment, during which microbial degradation evolves. Consistent with compound-specific dissipation in the mineral or organic environments, long-term concentrations of pentachloroaniline and hexachlorobenzene were lowest in the mineral-rich soils, while concentrations of dichlorodiphenyltrichloroethane (DTT) and metabolites were lowest in the organic soils of old market gardens. OM amendments changed pesticide dissipation in the mineral soil towards that observed in the organic soil; that is OM accelerated, slowed down or stopped dissipation.
  • Partovi, Fariba (Helsingin yliopisto, 2021)
    Utilization of pesticides in the modern agriculture is often indispensable for gaining good crops. However, pesticides are abundantly being used in too hight quantities which leads to potential health risks for the consumers. Currently there are no pre-screening methods for monitoring the levels of pesticides in food, but only a negligible small percentage of all goods are being tested using the laborious standardized methods. This master’s thesis is an investigation, that was carried out in the wet laboratory of KARSA Oy Ltd, on 10 different pesticides: Glyphosate, Thiabendazole, 2-phenylphenol, Chlorpyrifos, Fludioxonil, Chlormequat, Bupirimate, Diflubenzuron, Fenpyrazamine and 2,4-dichlorophenoxyacetic acid. Pesticides were ionized using straight radiation chemical ionization (SRCI) in positive and negative modes without any added reagent and also using bromide, nitrate, acetonylacetone and acetone as reagents. Charged target molecules and adducts were detected using Thermo fisher Iontrap/Orbitrap (LTQ Orbitrap velos pro upgraded) mass spectrometer. After the initial method development and scoping measurements pesticides were studied both individually and as a mixture of all 10 pesticides. Sample solutions were first injected with syringe so that the solvent and targets evaporated at the same time inside the desorber heating block of SRCI inlet. In these syringe injection measurements, the desorber temperature was set at 150 °C. Mass range at 125–750 has been used for all the pesticides except for Chlormequat (100–750). After the syringe injection measurements, the mixture of 10 pesticides was analysed by TCM filters. Target solutions of 1 µl volume were placed on filters and after the solvents had evaporated the filters were heated from room temperature to 245°C using the same setup as with the syringe injections. In conclusion, with syringe injections 7 pesticides out of 10 were detected using positive and negative mode without any added reagent. The highest target intensities were recorded from TCM filters. Overall, applying the SRCI-Orbitrap setup for pesticide pre-screening from target solutions resulted in the detection of 9 pesticides out of 10.
  • Iyer, J. G.; Chesters, G.; Wilde, S. A. (Suomen metsätieteellinen seura, 1969)
  • Laiho, Olavi; Mikola, Peitsa (Suomen metsätieteellinen seura, 1964)