Colombia using regionalization and scaling concepts with the long-term flow field as the scaling variable. All data sets, methods, and results are included in HidroSIG, an available interactive hydrologic atlas of Colombia.

West Africa and its people are very vulnerable to climate variability and changes. Increasing the knowledge of plausible trends of rainfall dry spell lengths (DSL) in the rainy season, and of runoff, enables the assessment of vulnerability and adaptive capacity of the system. These predictions are crucial from a water management and policy perspective. The analyses based on regional climate models (RCMs) and observed datasets exhibit non-stationary behavior and an increase of DSL. Our results highlight the difficulty of selected RCMs to reproduce present climate and their divergence in predicting future climate. Impacts on water resources depend not only on climate forcing but also on land surface conditions.

Heavy metal removal from wastewater is crucial for the proper management of discharged water from mining operations. This residual water is typically unusable for other purposes such as for human/animal, crop, or industrial consumption. Eco‐friendly adsorption materials are necessary to ensure the sustainable treatment of this wastewater. Therefore, the sorption of Cu(II), Cd(II), Pb(II), and Zn(II) ions onto chitosan–tripolyphosphate (CTPP) beads was investigated using real mining wastewater and prepared ion metal solutions. The effects of pH, contact time, temperature, selectivity, and maximum sorption capacity in successive batches at different concentrations were studied. The optimum sorption of cations, except for copper (pH 3) was found at pH 5. Equilibrium in the adsorption of all metals was reached at 24 h of contact. Studies of the maximum sorption capacity at different concentrations showed that the CTPP beads could adsorb 158, 55, 47, and 47 mg/g of Pb(II), Cu(II), Cd(II), and Zn(II), respectively. Experimental data for the sorption of Pb(II) were optimally correlated with the Langmuir model. The thermodynamic parameters such as the changes in enthalpy (ΔH0), entropy (ΔS0), and free energy (ΔG0) were determined. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45511.

An optimized spectroscopic methodology for the quantification of urea using p-dimethylaminobenzaldehyde (DMAB) as a derivatizing reagent is proposed to avoid changes in reproducibility caused by aging of acidic DMAB solutions, and the unintended use of different solvents. Four solvents; ethanol, methanol, 2-propanol and acetonitrile are evaluated. Acetonitrile has never been reported for the determination of urea with DMAB, and it is found to be the best medium for the quantification of urea due to its aprotic nature. The use of acetonitrile allows a more stable reaction system, which results in a faster urea quantification, less acid consumption and a more sensitive spectroscopic method. Taking into account that polymer matrices of chitosan are being used recently to develop controlled release fertilizers of urea, a complementary study is carried out to determine any interference by released chitosan macromolecules with different molecular mass and degree of deacetylation in the optimized system. The results show no appreciable changes in the sensitivity and accuracy of the methodology being other available application of this work.

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Pesticides are widely used in producing food to control pests. However, it has been determined that synthetic pesticides present severe toxicity (residual), while they also result in environmental contamination and development of high-level resistance in some insect species. Due to this, some of these susbtances have been banned or restricted in many countries, which has reduced the number of agrochemicals that can be used for pest control, particularly in the case of crops exported to green markets such as Europe and Asia. Under this scenario, essential oils (EOs) are being increasingly studied as bioinsecticides because they are renewable, natural, biodegradable, non-persistent in the environment and safe to non-target organism and humans. It has been determined that EOs have repellent, ovicidal, larvicidal, and insecticidal effects against different types of pests, but they also have some drawbacks due to their high volatility and low aqueous solubility. This mini-review focusses on EOs used as bioinsecticides for the control of Curculionidae and on current stabilization techniques, such as nanoencapsulation, to prolog the biocidal effect of EOs against these pests.

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