ELISA and HPLC methods for atrazine and simazine determination in trophic chains samples

Morphological and cellular effects in Boana faber tadpoles (Anura: Hylidae) exposed to atrazine-based herbicide and glyphosate-based herbicide and their mixtures

Atrazine and glyphosate are considered some of the main pollutants for aquatic ecosystems, directly and indirectly affecting non-target organisms, such as amphibians. This study aimed to evaluate the sublethal effects of different concentrations of atrazine-based herbicide (ABH) and glyphosate-based herbicide (GBH) commercial formulations, both individually and in a mixture, through toxicity tests on the larval stage of Boana faber. Tadpoles were exposed to concentrations of ABH (2, 9.33, 10.40, 47.21, and 240 μg L-1) and GBH (65, 144, 280, 500, and 1000 μg L-1), as well as a mixture ABH + GBH, for 7 days. Although survival and swimming activity were not significantly affected by herbicide exposure, tadpoles in all treatments showed damage to the mouth and intestine, changes in size and mass, and an increase in the frequency of micronuclei and other nuclear abnormalities. Despite differences in some variables analyzed, it is not possible to definitively state that there is a difference in the toxicity of these two herbicides, as both caused morphological damage and were cyto-genotoxic. Our findings suggest that exposure to commercial formulations of these herbicides, whether alone or in mixture, can directly impact the quality of life of B. faber tadpoles.

Impacts of earthworm casts on atrazine catabolism and bacterial community structure in laterite soil

Atrazine accumulation in agricultural soil is prone to cause serious environmental problems and pose risks to human health. Vermicomposting is an eco-friendly approach to accelerating atrazine biodegradation, but the roles of earthworm cast in the accelerated atrazine removal remains unclear. This work aimed to investigate the roles of earthworm cast in promoting atrazine degradation performance by comprehensively exploring the change in atrazine metabolites and bacterial communities. Our results showed that earthworm cast amendment significantly increased soil pH, organic matters, humic acid, fulvic acid and humin, and achieved a significantly higher atrazine removal efficiency. Earthworm cast addition also remarkably changed soil microbial communities by enriching potential soil atrazine degraders (Pseudomonadaceae, Streptomycetaceae, and Thermomonosporaceae) and introducing cast microbial degraders (Saccharimonadaceae). Particularly, earthworm casts increased the production of metabolites deethylatrazine and deisopropylatrazine, but not hydroxyatrazine. Some bacterial taxa (Gaiellaceaea and Micromonosporaceae) and humus (humic acid, fulvic acid and humin) were strongly correlated with atrazine metabolism into deisopropylatrazine and deethylatrazine, whereas hydroxyatrazine production was benefited by higher pH. Our findings verified the accelerated atrazine degradation with earthworm cast supplement, providing new insights into the influential factors on atrazine bioremediation in vermicomposting.

An overview of the potential impacts of atrazine in aquatic environments: Perspectives for tailored solutions based on nanotechnology

Atrazine is a pre- and post-emergence herbicide used to control weeds in many crops. It was introduced in the late 1950s, but its use has been controversial because of its high potential for environmental contamination. In agriculture, the implementation of sustainable practices can help in reducing the adverse effects atrazine. This review addresses aspects related to the impacts of atrazine in the environment, with focus on its effects on aquatic species, as well as the potential use of nanoencapsulation to decrease the impacts of atrazine. The application of atrazine leads to its dispersal beyond the immediate area, with possible contamination of soils, sediments, plantations, pastures, public supply reservoirs, groundwater, streams, lakes, rivers, seas, and even glaciers. In aquatic ecosystems, atrazine can alter the biota, consequently interfering in the food chains of many species, including benthic organisms. Nanoformulations loaded with atrazine have been developed as a way to reduce the adverse impacts of this herbicide in aquatic and terrestrial ecosystems. Ecotoxicological bioassays have shown that this nanoformulations can improve the targeted delivery of the active ingredient, resulting in decreased dosages to obtain the same effects as conventional formulations. However, more detailed analyses of the ecotoxicological potential of atrazine-based nanoherbicides need to be performed with representative species of different ecosystems.

Synthesis of Isotopically Labeled (13)C3-Simazine and Development of a Simultaneous UPLC-MS/MS Method for the Analysis of Simazine in Soil

The isotope dilution mass spectrometry (IDMS) is a highly efficient method for tackling the ion suppression in complex matrix by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), but a lack of commercial internal standards is a limiting factor for these analyses. Herein, an economical and efficient strategy for the synthesis of ¹³C₃-simazine via a three-step procedure was developed. The isotope-labeled internal standard was used for determination of simazine residue in soil samples. The quantitation method has a limit of detection of 0.015 μg/kg and quantitation of 0.08 μg/kg. The inter-day and intra-day precision of the method were below 4.6%. Recovery values were ranged between 92.9% and 99.2%. All the samples obtained from six provinces in China contained from 1 to 62 μg/kg of simazine.

Nucleophilic substitution as a mechanism of atrazine sequestration in soil

Formation of nonextractable residue was widely observed as a sink of atrazine (ATZ) in soil. However, the mechanisms by which ATZ binds to soil organic matter remain unclear. In this study, we demonstrated that neucleophilic substitution could serve an important pathway causing ATZ sequestration. The carbon bonded to the chlorine in ATZ molecule is partially positively charged due to the strong electronegativity of chlorine and is susceptible to the attack of nucleophiles such as aniline. Since aromatic amines are relatively rare in natural soils, amino acids/peptides were hypothesized to act as the main nucleophiles in real environment. However, substantially ATZ transformation was only observed in the presence of those species containing thiol functionality. Thus, we speculated that it was the thiol group in amino acids/peptides acting as the nucleophile. Nitrogen in amino acids was in fact not an active nucleophile toward ATZ. In addition to the sulfur-containing amino acids, other thiol compounds, and sulfide were also proved to be reactive to ATZ. Thus, the sequestration potential of ATZ probably correlates to the availability of thiol compounds in soil.

Degradation of simazine from aqueous solutions by diatomite-supported nanosized zero-valent iron composite materials

A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI/diatomite composites were characterised by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI/diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesised nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilising nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero-valent iron composite materials have potential applications in environmental remediation.

Preparation of antibodies and development of an enzyme immunoassay for determination of atrazine in environmental samples

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed and optimized for atrazine determination in soil at different depths (0-10, 10-20, and 20-30 cm) before and after 48 h of application, corn shoot and cow milk samples collected from Dina farm, Egypt. This assay was based on a specific polyclonal antibodies (PAb) raised by immunizing New Zealand rabbits with an immunogen prepared by coupling 3-{4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine-2-yl} thiopropanoic acid to bovine serum albumin (BSA) via N-hydroxysuccinimide (NHS) active ester method. The sensitivity (estimated as IC₅₀ value) was 17.5 μg mL⁻¹ with a detection limit of 0.1 ng mL⁻¹. The maximum atrazine concentration was found in soil especially in the deepest layer (325 and 890 μg kg⁻¹ before and after application, respectively). Atrazine concentration in corn shoot was 333.28, μg kg⁻¹ dry plant, while there was no detectable amount in milk. All samples screened by ELISA were validated by gas chromatography mass spectrometer procedure (GC/MS). Good correlation was achieved between the two methods (r = 0.997 for soil and 0.9814 for plant). This study demonstrates the utility and convenience of the simple, practical and cost-effective ELISA method in the laboratory for analysis of environmental samples. The method is ideal for the rapid screening of large numbers of samples in laboratories where access to GC/MS facilities, is limited or lacking.

Procedures for analysis of atrazine and simazine in environmental matrices

There is an ongoing need to monitor soil and trophic chain samples for residues of triazine herbicides, particularly atrazine and simazine, because these herbicides are among the most used members of their class, are toxic, can be persistent, and are widely distributed in the environment. The main purpose of this review is to provide an overview of principle techniques and approaches used in analyzing atrazine, simazine, and other triazine herbicide residues in environmental matrices. The methods covered generally provide low detection limits, acceptable levels of matrix interferences, and are relatively fast and inexpensive. Atrazine and simazine are popular herbicides used to control a variety of broad leaf and grassy weeds in agriculture and on industrial sites. Because they are widely and frequently used, the environmental contamination of these compounds is considerable. Atrazine, simazine, and other triazines have the ability to translocate in ecosystems. When this occurs, it is often necessary to monitor their residue content in soils, vegetation, biota, and water. There is a vast literature available that addresses the extraction and clean-up of soil, vegetation, animal tissue, and animal fluid samples; unfortunately, few of these publications compare the effectiveness of results obtained on similar matrices. In this review we endeavor to review and provide comparative information on methods dedicated to determining residues of atrazine, simazine, and other triazines in several environment matrices: soil, plants, animal tissues, and water.