Estimated Levels of Environmental Contamination and Health Risk Assessment for Herbicides and Insecticides in Surface Water of Ceará, Brazil.

Methodology using solid phase extraction and high performance liquid chromatography (SPE-C18/HPLC-DAD) was applied to pesticide determinations in ten water reservoirs in the semidarid region of northeastern Brazil. The validated method was suitable for determination of herbicides and insecticide in surface water. The recovery efficiency of atrazine, methyl-parathion and simazine was approximately 70%. The method also showed good linearity and selectivity with correlation coefficients (R) greater than 0.99. The limits of detection were below the maximum residue limits (MRLs) established by government agencies. Studied reservoirs showed presence of atrazine at mean levels from 7.0 to 15.0 µg/L. Simazine and methyl parathion were not detected during the period. The atrazine levels measured from this semiarid region are of the same magnitude as those found in regions with moderate to high agricultural activity. According to detected atrazine concentrations, the annual health risk to humans was insignificant. However, the control of herbicides is important to maintain the quality of water in the reservoirs of Ceará, Brazil.

Diagnostic detection systems and QuEChERS methods for multiclass pesticide analyses in different types of fruits: An overview from the last decade.

This manuscript is a bibliographic review about analyses of different classes of pesticide in fruits using QuEChERS as sample preparation methodology. The aim is to clarify different trends and facilitate decision-making by the scientific community in order to carry out further studies in this field. It is well known that different countries have different pesticides regulations for maximum level of pesticide residue permitted. The comparative analysis amongst the main producer countries reveals that for some fruits they are not studied enough. Recent improvements to QuEChERS make it possible to minimize the pesticides instability due the matrix pH, and achieving cleaner extracts. Regarding the detection systems, the tandem MS are preferred once they have high sensitivity and selectivity, although traditional techniques (GC-ECD and HPLC-DAD) are still commonly used due to their accessibility and good sensitivity to some pesticides. Also, studies involving metabolites usually show that they are more toxic than their precursor compounds.

Removal of some polycyclic aromatic hydrocarbons from petrochemical wastewater using low-cost adsorbents of natural origin.

Removal of polycyclic aromatic hydrocarbons (PAHs) from petrochemical wastewater was investigated using various low-cost adsorbents of natural origin including sugar cane bagasse, green coconut shells, chitin, and chitosan. Adsorption experiments of mixtures of PAHs (5.0-15.0 mg/L) have been carried out at ambient temperature (28+/-2 degrees C) and pH 7.5. The adsorption isotherms of PAHs were in agreement with a Freundlich model, while the uptake capacity of PAHs followed the order: green coconut shells>sugar cane bagasse>chitin>chitosan. The adsorption properties of green coconut shells were comparable to those of some conventional adsorbents such as Amberlite T. The partition coefficients in acetone:water, the adsorption constants at equilibrium, and the molecular masses of the PAHs could be linearly correlated with octanol-water partition coefficients.