Biochar a promising strategy for pesticide-contaminated soils

Soil pesticide contamination induced by modern agriculture has become a serious global issue. Its uncontrolled and inefficient application is among the main reasons for their enrichment in plants and animals subsequently transferred to humans and providing a public health risk. Biochar as a renewable and economical carbonaceous material provides a natural solution for immobilizing pesticides and improving soil health. The biochar impact in agricultural contaminated soil is governed by various factors such as the physico-chemical properties of biochar, pyrolysis, soil conditions, and the application method, which can lead to significant gaps in the removal or mitigation of toxic substances. The current study summarizes the negative effects of pesticide use and the advantages of biochar according to other remediation techniques, succeeded by the mechanism and controlling factors on minimizing pesticide leaching and bioavailability in soil. In addition, the role of biochar on fundamental processes of adsorption, desorption, biodegradation, and leaching is discussed. Ultimately, the major future research regulation and key strategies that are fundamental for pesticidecontaminated soil remediation are proposed

Sorption and leaching of s-metolachlor in surface horizons of Romania

Sorption is the major process that determines the fate and behavior of most herbicides in soil. Understanding herbicide sorption within soil profile is the first step to predict groundwater contamination. Laboratory studies were conducted to determine the influence of surface soil properties on s-metolachlor sorption. Sorption isotherms were determined from soil plough layer (0-25 cm) using the batch equilibrium method and six concentration (0, 1, 5, 10, 20 and 50 mg L-1). Sorption affinity of herbicide was approximated by the Freundlich equation. The environmental behavior of smetolachlor was studied at the Didactical and Experimental Research Station Ezareni belonging to ’’Ion Ionescu de la Brad’’ University of Agriculture and Veterinary Medicine Iasi, Romania. A randomized complete block design with three replications was used in the experiment. S-metolachlor EC (96% v/v) was applied as a pre-emergence at dosages of 1500, 2100 and 2700 mL ha-1 1 day before sowing the soybean seeds in the field. The soil was collected at different layers and the residues of s-metolachlor were analyzed by GC-MS. Maximum concentration of s–metolachlor was recovered from 0-15 cm depth in all three doses. Results indicated high mobility of s-metolachlor under field conditions that may be significant in terms of ground water contamination

Analyzing soil porosity under different tillage systems using X-ray microtomography

X-ray computed tomography is one of the modern techniques used for soil structure visualization and quantification. The aim of this study was to investigate the effects of different tillage systems on soil porosity. Soil samples were collected from the field, on 0-30 cm depth, within the Experimental Farm of the Agricultural University of Iasi, North East of Romania, from a long term experiment with three tillage systems: V1 - chisel, V2 – no-till, V3 - plough at 30 cm. Aggregates were scanned using a SkyScan 1172 microCT and then the reconstructed 3D images were analyzed, in order to investigate pore volume and pore size class distribution. The results of the porosity analysis revealed significant differences between the variants taken into study. Regarding the solid surface area the tillage systems determined very different values of this parameter in soil. Pore size class distribution also showed clear differences between the variants. X-ray CT proved to be a useful tool for soil analysis, in order to have a detailed view of the pore network

Mixture support for essential elements and its effect on Zn and Cd sorption

Zinc and Cadmium are elements similar in chemical properties but different in mobility and availability, used as stress factors and contaminants. The aim of the study was to establish the sorption capacity of Zn (II) and Cd (II) on a nutrient mixture, the conditions under which the process is maximal and the changes that undergo in the chemical composition of the mixture. The mixture consists in eutrophic peat and compost (60:40%), which contains in addition to organic matter, macronutrients (N, P, K) and certain content of inorganic contaminants (Ni, Pb, Co, Cd, Zn). The parameters that influence the sorption process on nutrient mixture were: initial solution pH (1.0-9.0), contact time (0-1200 min), Zn and Cd concentrations (50-250 mg/l) and organic matter content (52%). The results show that certain characteristics such as phosphorus and potassium content did not change significantly, while the organic matter content decreased to 45%. The humic acids from the organic matter composition caused a significant immobilization of Zn (II) and only a slight immobilization of Cd (II). The values of Cd and Zn from nutritive solution are higher (42.24 mg/kg Zn and 11.69 mg/kg C) than accessible fraction (19.26 mg/kg Zn and 1.4675 mg/kg Cd). The heavy metals content decreases with the increase of pH (5.0 mg/kg Cd, 3.0 mg/kg Zn). The content of accessible fraction reveal reduced values of Cd and Zn that does not represent a threat for human health. These organic materials improve soil fertility, can change the availability of heavy metals and increase crop production

TRANSFER OF HEAVY METALS IN SOIL IN-PLUM CULTIVATION: A FIELD STUDY IN ADAMACHI IASI, ROMANIA

Currently, global environmental concerns about heavy metal pollution are driven by rapid urbanization and industrial development. Therefore, a field study was conducted to assess the concentration of heavy metals (Pb, Co, Zn, Ni and Cu) in orchard soils and its transfer to two plum varieties (Stanley and Anna Späth) at Adamachi Farm – Iasi University of Life Sciences (IULS). In addition, heavy metal transfer (MTF), daily metals intake (DIM) and the index of health risk (HRI) were evaluated. The concentration of Pb, Co, Zn, Ni and Cu in soil and plum leaves samples were analyzed using atomic absorption spectrometry after acid digestion with a mixture of HNO3 (65%), HCl (37%) and HClO4 (60%). Metal concentration patterns occurred as follows 130.65>76.6>30.36> 21.69>13.26 mg/kg for Cu, Zn, Ni, Pb and Co in soil samples and 20.16>10.00> 2.10>1.68 mg/kg for Zn, Cu, Ni and Pb in plum leaves, while Co residue was not detected. The maximum heavy metal concentrations were found at the soil surface (0 – 30 cm depth) due to soil organo-mineral content and antifungal treatments. The health risk index predicted (HRI) for adults as well as children was in the sequence Pb > Cu > Ni > Zn, suggesting no health risk with values that did not exceed the safe limit (1). Therefore, it is essential to manage the causes and sources of heavy metal transfer prudently and effectively in order to prevent environmental contamination

Transfer of heavy metals in soil in-plum cultivation: a field study in Adamachi Iasi, Romania

Currently, global environmental concerns about heavy metal pollution are driven by rapid urbanization and industrial development. Therefore, a field study was conducted to assess the concentration of heavy metals (Pb, Co, Zn, Ni and Cu) in orchard soils and its transfer to two plum varieties (Stanley and Anna Späth) at Adamachi Farm – Iasi University of Life Sciences (IULS). In addition, heavy metal transfer (MTF), daily metals intake (DIM) and the index of health risk (HRI) were evaluated. The concentration of Pb, Co, Zn, Ni and Cu in soil and plum leaves samples were analyzed using atomic absorption spectrometry after acid digestion with a mixture of HNO3 (65%), HCl (37%) and HClO4 (60%). Metal concentration patterns occurred as follows 130.65>76.6>30.36> 21.69>13.26 mg/kg for Cu, Zn, Ni, Pb and Co in soil samples and 20.16>10.00> 2.10>1.68 mg/kg for Zn, Cu, Ni and Pb in plum leaves, while Co residue was not detected. The maximum heavy metal concentrations were found at the soil surface (0 – 30 cm depth) due to soil organo-mineral content and antifungal treatments. The health risk index predicted (HRI) for adults as well as children was in the sequence Pb > Cu > Ni > Zn, suggesting no health risk with values that did not exceed the safe limit (1). Therefore, it is essential to manage the causes and sources of heavy metal transfer prudently and effectively in order to prevent environmental contamination

Selective and sensitive quantification of acetochlor and s-metolachlor in maize and soybean plant samples by Gas chromatography-tandem mass spectrometry

Abstract: Herbicide residue analysis has gained importance worldwide, mainly for food quality control to minimize potentially adverse impacts on human health. A Gas chromatography-tandem mass spectrometry (GC-MS) method for quantitative analysis of acetochlor and s-metolachlor in maize and soybean straw has been developed, validated and applied to analyze the residues of anilide herbicides. Straw material was dried, homogenized and extracted with a mixture of nhexane and acetone by an accelerated solvent extraction method. Chromatographic separation of the target analytes was performed on an Agilent 7832 GC equipped with a mass spectrometer detector, a split-splitless injector and an HP-5 MS (5% phenylmethyl siloxane) capillary column (30 m 0.25 mm 0.25 m). Under these parameters, the limit of detection (LOD) values were 0.2 ng g1 for acetochlor and 0.07 ng g1 for s-metolachlor, with average recoveries between 86% and 119.7%. The method was validated for acetochlor and s-metolachlor in maize and soybean straw at 0.5 and 0.01 mg kg 1. Furthermore, the final residues of the two herbicides in maize and soybean straw were below the maximum residue limit (MRL) at harvest time. The proposed method is suitable for routine analysis

Residues of acetochlor herbicide in soybean and soil in Moldavian field

Herein, we report the results of a study aimed at estimating the potential of acetochlor for translocation into soybean plants and groundwater and its retention in one of the most common soil in Romania. The chloroacetanilide herbicide acetochlor was applied at three different dosages, i.e. 2.2 L ha-1 (Recommended dose), 3.1 L ha-1 (40%+Recommended dose) and 3.96 L ha-1 (80%+Recommended dose) as a pre-emergent spray on soybean crop at 3 days after sowing in the experimental field of Ezăreni – The Experimental Farm of the Agricultural University Iasi. Analyses were performed using Gas chromatography mass spectometry (GC-MS). Extraction of field soil samples taken from different depths (0- 5, 5-10, 10-15 and 15-20 cm) at different times after herbicide application, showed that all applied doses moved deeper and increased dose (80%+Rd) affected the persistence of acetochlor in the top layer increasing its half-life to 5 days. Dissipation followed a first order kinetics. At harvest, soil and plant samples were found to contain acetochlor below maximum residue limits (MRL) following the 80%+ recommended dosag

Biochar a Promising Strategy for Pesticide-Contaminated Soils

Soil pesticide contamination induced by modern agriculture has become a serious global issue. Its uncontrolled and inefficient application is among the main reasons for their enrichment in plants and animals subsequently transferred to humans and providing a public health risk. Biochar as a renewable and economical carbonaceous material provides a natural solution for immobilizing pesticides and improving soil health. The biochar impact in agricultural contaminated soil is governed by various factors such as the physico-chemical properties of biochar, pyrolysis, soil conditions, and the application method, which can lead to significant gaps in the removal or mitigation of toxic substances. The current study summarizes the negative effects of pesticide use and the advantages of biochar according to other remediation techniques, succeeded by the mechanism and controlling factors on minimizing pesticide leaching and bioavailability in soil. In addition, the role of biochar on fundamental processes of adsorption, desorption, biodegradation, and leaching is discussed. Ultimately, the major future research regulation and key strategies that are fundamental for pesticide-contaminated soil remediation are proposed