Assessment of pesticide availability in soil fractions after the incorporation of winery-distillery vermicomposts

The influence of two vermicomposts from winery and distillery wastes on the distribution of diuron in agricultural soil was studied. Physical soil fractionations at 0, 9, 27, 49 and 77 days, allowed the quantification of pesticide residues in different particle-size fractions, coarse waste (WF), sand-sized (SF), silt-sized (SiF), clay-sized (CF) and dissolved organic matter-sized fraction (DOM). The SiF made a greater contribution to the formation of non-extractable residues in unamended soil, but when vermicomposts were added, new sorption sites in WF appeared, being higher for the more humified vermicompost V2. The dissolved organic carbon (DOC) increased with the addition of vermicompost, but the concentration of the desorbed 14C-radiochemical did not increase. Non-significant increment was observed with time for the non-extractable fraction with amendments. Diuron was transformed in all samples, although less than 0.5% was mineralized. The main effect caused by vermicomposts was a reduction in the availability of diuron in soil.     

Leaching of mecoprop and dichlorprop in calcareous soil. Effect of the exogen organic matter addition in this process.

Leaching studies of mecorprop (R,S)-2-(4-chloro-2-methylphenoxy)propanoic acid, and dichlorprop, (R,S)-2-(4-chloro-2,4-dichlorophenoxy) propanoic acid, under saturated conditions were conducted in unamended and amended soil columns. The purpose of the study was to investigate the leaching of these herbicides in three type of soils and the exogen organic matter effect on this process. The leaching patterns could be related to variation in the soil texture and diffusion processes of the herbicides into micropores within the walls of conducting pore. The leaching rate in the amended soil columns decreased with the addition of organic matter. The breakthrough curves (BTC) of these herbicides in the leachates of the amended soil columns were wider and more diffused than the BTC obtained for the corresponding unamended soil. The theoretical BTC overestimated the pore volume required for the displacement of these pesticides from the soil column. This may be due to the differences in the adsorption process between the bacth and soil columns methods.     

Production and Characterization of Bioplastics Obtained by Injection Moulding of Various Protein Systems

Bioplastic materials from renewable polymers, like proteins, constitute a highly interesting field for important industrial applications such as packaging, agriculture, etc., in which thermo-mechanical techniques are increasingly being used. This study assesses bioplastic materials produced by injection from blends previously prepared in a batch mixer using various protein concentrates and isolates. A mixing time of 5 min has been selected in order to ensure correct homogenous blends. A comparison between different protein-based specimens was performed by dynamic mechanical thermal analysis, tensile strength, water uptake and transmittance tests. The comparison reveals that the protein nature and the percentage of plasticizer lead to bioplastics with different properties and, consequently, different applications. Protein concentrates and isolates, wastes and surpluses from the food industry, may be useful for producing bioplastics with suitable mechanical properties and processability, as well as biodegradability, by means of suitable mixing and injection moulding conditions.     

Removal of organochlorine pesticides from lindane production wastes by electrochemical oxidation

This study is focused on the effective removal of recalcitrant pollutants hexaclorocyclohexanes (HCHs, isomers α, β, γ, and δ) and chlorobenzenes (CBs) present in a real groundwater coming from a landfill of an old lindane factory. Groundwater is characterized by a total organic carbon (TOC) content of 9 mg L^?1, pH₀?=?7, conductivity?=?3.7 mS cm^?1, high salt concentration (SO₄^2?, HCO₃^?, Cl^?), and ferrous iron in solution. The experiments were performed using a BDD anode and a carbon felt (CF) cathode at the natural groundwater pH and without addition of supporting electrolyte. The complete depletion of the four HCH isomers and a mineralization degree of 90% were reached at 4-h electrolysis with a current intensity of 400 mA, the residual TOC (0.8 mg L^?1) corresponding mainly to formic acid. A parallel series reaction pathway was proposed: HCHs and CBs are transformed into chlorinated and hydroxylated intermediates that are rapidly oxidized to non-toxic carboxylic acids and/or mineralized, leading to a rapid decrease in solution pH.     

Sustainability of forest management plans: a discrete goal programming approach

Let us consider i = 1, 2,...n alternative forest plans to be evaluated according to j = 1, 2,...m indicators of sustainability. An expert or panel of experts suggests a set of targets or desirable levels of achievement for the m indicators of sustainability considered. Within this context, an important problem is to determine the system with a higher level of achievement with respect to the targets attached by the expert to the m indicators. A natural extension of this problem involves determining a ranking of the n systems considered. A general procedure based on discrete goal programming is proposed to address these problems. The methodology is applied in a case study of a Spanish forest.     

Growth conditions,elemental accumulation and induced physiological changes in Chinese cabbage

Soils contaminated with low levels of heavy metals and other trace elements are now frequently used for vegetable growing. In this situation, heavy metals and trace elements from these polluted soils may accumulate in the agricultural plants being grown in them and thereby enter the human food chain. The objectives of this study are to elucidate the effects of growth conditions, manipulated by the crop covers, on the phytoaccumulation of elements, and to investigate the conceivable influences of these conditions on the plant biochemistry. In three consecutive years of field experiments, open air (T(0)), and floating rowcover treatments (T(1): perforated polyethylene 50 micrometers; T(2): polypropylene 17 gm(-2)) were used to produce different environmental conditions for the growth of Chinese cabbage [Brassica rapa L. (Pekinensis group) cv. 'Nagaoka 50']. Five samplings (whole tops) were carried out from transplanting to harvest and measurements of B, Al, Ag, Si and Ca concentration as well as phenolics (orto-diphenols, total phenols and anthocyanins), pectic fractions, amino acids (histidine, phenylalanine and tyrosine) and polyphenol oxidase activity, were carried out in samples. The T(1) (perforated polyethylene sheet) gave greater B, Al, Ag and Si concentration and phytoextraction (in weight units) than the open-air control. These findings can help to develop new cost-effective techniques for phytoremediation as the application of plastic covers in the field. The build-up of heavy metals in those crops would make the product less suitable for human consumption.     

Ability of biosolids and a cationic surfactant to modify methidathion leaching. Modelling with pescol

Packed columns were prepared with an agricultural soil to examine the ability of two organic soil modifiers, biosolid and the cationic surfactant tetradecyl trimethyl ammonium bromide (TDTMA), to alter the leaching of the insecticide methidathion. Ion chloride was used as a tracer of water flow and the mathematical model PESCOL was selected to predict the mobility of the insecticide. The biosolid addition (SB column) delayed the breakthrough curves for methidathion with respect to the non-amended soil (S) column. The cationic surfactant TDTMA, alone or combined with the biosolid (SS and SBS) and previously incorporated in the soil column, caused the highest retardation of this pesticide in the soil columns. Theoretical retardation factors (TRf) were similar to the experimental Rf values for the S and SB columns, and predicted the high retention observed in the SBS and SS columns. The simulation with PESCOL predicted the experimental results.