Background: The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method can be employed for multi-residue analyses instead of traditional extraction methods due to its advantages in terms of extraction time and required equipment. A modified version of the QuEChERS method has been developed for quantifying eight pharmaceuticals belonging to different classes in three real soils with different chemical properties. Firstly, the soils have been polluted with all contaminants and the recoveries were determined by liquid chromatography tandem–mass spectrometry. Due to similar recoveries from the three soils, the validation of the method has been carried out only on a soil by determining linearity, recovery, precision, limit of detection (LOD) and limit of quantification (LOQ) values. A matrix-matched calibration for the soil has been adopted in order to avoid the matrix effect and three levels of fortification (50, 100 and 500 µg L−1) were used. Results: The recovery of all pharmaceuticals, with the exception of tetracycline, from any soil was between 72 and 113%. In the validation procedure, recoveries of fortified samples ranged from 80 to 99%, the relative standard deviations ranged between 1.2 and 11.8%, and the LOQ between 20 and 36.9 μg kg−1. Conclusion: The results of the present study confirmed the validity of the modified QuEChERS method for the extraction of pharmaceuticals from soils in the range 50–500 μg kg−1. Graphical
11 December 2017 in Land Degradation & Development
Background: The irrigation with treated wastewaters can be a way for the introduction of organic contaminants in soils. However, their adsorption onto soils can allow a control of their bioavailability and leaching. The adsorption is influenced by properties of contaminants (water solubility, chemical structure) and soils (organic matter content, pH, mineralogy). This study aimed to investigate the effect of mineralogical composition, organic matter content and others parameters of soils on the adsorption of sulfamethoxazole (SMX) and diclofenac (DCF), two contaminants of emerging concerns (CECs), in real cases (Altamura, Sibari and Noci soils). Results: The isotherms data showed that the adsorption of the two CECs closely matched the Freundlich model, even if the DCF could also fit the linear one. The only exception was the adsorption of SMX on the soil of Sibari, for which Langmuir's model fitted better. In all cases, the Kd values were the highest for Altamura soil according mainly to its content of organic carbon. Positive correlations were found between Kd value of DCF and the soil organic carbon and Al oxyhydroxides content, suggesting their roles in its adsorption, while SMX showed only a slight positive correlation with the soil organic carbon content. Finally, between the two CECs studied, DCF was more adsorbed than SMX also because of the lower water solubility of the former. Conclusions: The good interaction between DCF and soil organic carbon suggests the organic amendment of soils before the application of treated watewaters. The low adsorption of SMX onto soils suggests greater leaching of this compound which is, therefore, potentially more dangerous than DCF. For this reason, the application of a filtration system with appropriate adsorbent materials before the application of wastewater to soils should be expected. Graphical
The interaction of organic matter with the finest soil fractions (250 μm) is highest in the upper soil layer, while the finest fraction is in the deepest one. The greatest OC content is observed in the topsoil layer and in the finest soil fraction. DRIFT analysis suggests that organic components are more present in the finest fraction, calcite is mainly localized in the coarse fraction, quartz is in micro-aggregates and 53–20 μm fraction, and clay minerals are in the finest fraction.
Pleurotus ostreatus is one of the most cultivated mushrooms worldwide. It is a lignocellulolytic fungus cultivated on different substrates, whose more common raw material is straw. The present study investigated the biological efficiency of Pleurotus ostreatus as affected by the different age of straw and the growing media preparation process in four production cycles. The content of organic carbon significantly decreased during the growing media preparation, while the content of total nitrogen, moisture, and ash, as well asthe pH value, showed an opposite trend. The first production cycle was characterized by the highest total and soluble sugar content. A dramatic reduction in soluble sugars was recorded at the end of the preparation of the growing media, regardless of the production cycle, while the total sugars were slightly reduced during the production cycle. The microbial population was significantly influenced by the growing media preparation, while only bacteria were slightly influenced by the straw’s age. In contrast, cellulase activity significantly increased in the old straw, while an opposite trend was observed for pectinase activity. The β-glucosidase activity was influenced only by the growing media preparation. As expected, cluster analysis showed that the microbial community changed in each phase of growing media preparation. Finally, the biological efficiency of Pleurotus ostreatus decreased from 26.28% to 15.49% with increasing age of the straw, which may presumably be ascribed to the higher content of sugars in fresh straw compared to the older ones. Therefore, fresh straw should be used to prepare the growing media of Pleurotus ostreatus in order to increase its biological efficiency.