In this study, carbon nanotube-based adsorbents, oxidized multi-walled carbon nanotube (OMWCNT) with non-magnetic property and OMWCNT-Fe₃O₄ and OMWCNT-κ-carrageenan-Fe₃O₄ nanocomposites with magnetic property, having different structural and surface properties were prepared and their adsorptive properties for the removal of toxic diquat dibromide (DQ) herbicide from water by adsorption were determined in detail. For each adsorption system, the effects of initial DQ concentration, contact time and temperature on the adsorption processes were determined. Equilibrium time was found to be 300 min for DQ solutions. OMWCNT showed faster adsorption and higher maximum adsorption capacity value than magnetic adsorbents. With increasing initial herbicide concentration from 5.43 mg.L⁻¹ to 16.3 mg.L⁻¹, the values of initial sorption rate exhibited a decrease from 29.1 mg.g⁻¹.min⁻¹ to 4.28 mg.g⁻¹.min⁻¹ for OMWCNT-DQ system, from 1.21 mg.g⁻¹.min⁻¹ to 0.823 mg.g⁻¹.min⁻¹ for OMWCNT-Fe₃O₄-DQ system and from 0.674 mg.g⁻¹.min⁻¹ to 0.612 mg.g⁻¹.min⁻¹ OMWCNT-κ-carrageenan-Fe₃O₄ system. Maximum adsorption capacity value of OMWCNT was approximately 2.8-fold higher than magnetic OMWCNT-Fe₃O₄ and 5.4-fold higher than magnetic OMWCNT-κ-carrageenan-Fe₃O₄ at 25 °C. Adsorption kinetic and isotherm data obtained for all adsorption systems were well-fitted by pseudo second-order and Langmuir models, respectively. Thermodynamic parameters indicated that the adsorption of DQ onto carbon nanotube-based adsorbents was spontaneous and endothermic process. Furthermore, OMWCNT having the highest herbicide adsorption capacity could be regenerated and reused at least five times. This study showed that carbon nanotube-based adsorbents with magnetic and non-magnetic property were of high adsorption performance for the removal of DQ from water and could be promising adsorbent materials for the efficient removal of herbicides from wastewaters.

A full life-cycle (240 days) bioassay using the terrestrial snail, Cantareus aspersus, allowing exposure during embryogenesis and/or the growth and reproduction phases, was used to assess the effects of Bypass®, a glyphosate-based herbicide (GlyBH), on a range of endpoints, including parameters under endocrine control. As a positive control, a mixture (R-A) made of diquat (Reglone®) and nonylphenols (NP, Agral®), known for its endocrine disrupting effects in other organisms, was tested. At environmental concentrations, both pesticides (R-A mixture and GlyBH) enhanced growth but reduced reproduction. The R-A mixture acted mainly on the fecundity through a delay in egg-laying of approximately 20 days and a strongly reduced number of clutches. This latter dysfunction may be caused by a permanent eversion of the penis, suggesting a disrupting effect at the neuro-endocrine level, which prevented normal mating. GlyBH acted on fertility, possibly due to a decrease in the fertilization of eggs laid by adults exposed during their embryonic development. These results, associated with the absence of observed effects on gonad histology of GlyBH exposed snails, suggested that the underlying mechanisms are neuro-endocrine.

Paraquat (PQ) is one of the most commonly used herbicides, but it has polluted the environment and threatened human health through extensive and improper usage. Here, a new naked-eye PQ immunochromatographic strip was developed to recognize PQ in domestic water and real human samples within 10 min based on a novel custom-designed anti-PQ antibody. The PQ test strip could recognize PQ at a concentration as low as 10 ng/ml, reaching the high-efficiency time-of-flight mass spectrometry detection level and identifying trace amounts of PQ in samples treated with a diquat (DQ) and PQ mixture. Notably, both the performance evaluation and clinical trial of the proposed PQ strips were validated in multiple hospitals and public health agencies. Taken together, our study firstly provide the clinical PQ-targeted colloidal gold immunochromatographic test strip designed both for environment water and human sample detection with multiple advantages, which are ready for environmental monitoring and clinical practice.

Neonicotinoid pesticide use is widespread and highly debated, as evidenced by recent attention received from the public, academics and pesticide regulatory agencies. However, relatively little is known about the physiological effects of neonicotinoid insecticides on aquatic vertebrates. Amphibians (larval stages in particular) are excellent vertebrate bioindicators in aquatic systems due to their risk of exposure and sensitivity to environmental stressors. Previous work with wood frog (Rana sylvatica) tadpoles exposed to formulated products containing thiamethoxam or clothianidin in outdoor mesocosms found significant shifts in leukocyte profiles, suggesting the tadpoles were physiologically stressed. The main objective of the present study was to characterize this stress response further using complementary measures of stress after exposure to clothianidin on northern leopard frogs (Rana pipiens) during their aquatic larval stages. Laboratory static-renewal exposures were conducted over eight weeks with the technical product clothianidin at 0, 0.23, 1, 10 and 100 μg/L, and diquat dibromide at 532 μg/L was used as a positive control. We assessed tadpole leukocyte profiles and measures of oxidative stress as these sub-lethal alterations could affect amphibian fitness. We found changes in several types of leukocytes at 1 and 10 μg/L, suggesting that these tadpoles exhibited signs of mild physiological stress. Clothianidin also induced an oxidative stress response at 0.23, 1 and 100 μg/L. However, we found no differences in survival, growth, development time or hepatosomatic index in frogs exposed to clothianidin. Our study indicates that tadpoles chronically exposed to clothianidin have increased stress responses, but in the absence of concentration-response relationships and effects on whole-organism endpoints, the implications on the overall health and fitness of these changes are unclear.

Lyngbya wollei is a filamentous cyanobacterium that causes numerous adverse impacts in reservoirs and lakes, such as toxin production, harboring fecal bacteria, devaluing property, impeding navigation/recreation, and degrading wildlife habitat. This study assessed a chemical treatment program in a Southeastern USA reservoir using a chelated copper formulation (Captain® XTR) in combination with diquat dibromide (Tribune®) over 2 years. The treatment program consisted of multiple applications during the summer and fall months. Overall, biomass decreased significantly (α = 0.05) in the two treated coves, by 97 and 80%, whereas L. wollei increased significantly (α = 0.05) in the untreated reference cove, by 25,127%. During the study, the quantity of algaecide applied was decreased in one of the treatment coves to adjust for the reduction in L. wollei biomass, as well as reduction in treated area, as part of an adaptive management strategy. The measured exposure demonstrated the residence time of the copper algaecide was short, with most of the copper dissipating in hours, which was attributed to sorption to L. wollei, sediments, and dilution. The biomass monitoring procedure, used transects spaced in 150 m intervals and sampled algae at 0–2 m, 5–7 m, and 10–14 m distances from shore, was effective at discerning changes in L. wollei biomass in the treated and untreated coves. This study indicated that the treatment program was effective for reducing L. wollei biomass and demonstrated the utility of the surveying technique to implement adaptive management of this filamentous cyanobacterium.

The electrochemical elimination of the herbicide diquat dibromide (DQ) in an undivided electrochemical cell (Condiacell®-type cell) and an H-type cell (a divided electrochemical cell) using boron-doped diamond (BDD) electrodes is reported for the first time. The degradation of essentially 100% of the DQ present was achieved in the undivided electrochemical cell and ca. 92% in the H-type cell. Nearly 80% of the total organic carbon (TOC) and of the chemical oxygen demand (COD) were removed after 5 h of treatment at different current densities (i.e., 0.5, 1.0, and 1.5 mA/cm² for the undivided cell, and 2.5, 5.0, and 7.5 mA/cm² for the H-type cell) with a maximum specific energy consumption of approximately 150 kWh kg⁻¹ of COD degraded in the undivided cell, and 300 kWh kg⁻¹ of COD in the H-type cell. Energy consumption of about 0.30 kWh g⁻¹ of TOC occurred in the undivided electrochemical cell and 2.0 in the H-type cell. In spite of obtaining similar percentages of DQ degradation and of COD and TOC removal, a smaller energy usage was required in the undivided cell since smaller current densities were employed. Best results were obtained with the undivided cell, since it required a smaller current density to obtain virtually the same percentage of DQ degradation and removal of COD and TOC. The results obtained herein show that the use of electrochemical advanced oxidation processes may be a good alternative for DQ degradation in polluted water.

Diquat dibromide is a comprehensive herbicide commonly used in the cultivation of cotton, soybeans, and other crops to combat unwanted weeds. In this study, the half-maximal effective concentration (EC₅₀) value of diquat dibromide was determined 60 mg/L in the Allium root growth inhibition test. ½ × EC₅₀ (30 mg/L), EC₅₀ (60 mg/L), and 2 × EC₅₀ (120 mg/L) concentrations of diquat dibromide were applied to Allium cepa L. bulbs for 72 h to investigate the dose-dependent toxic effects. To determine the toxic effects cytogenetic, biochemical and physiological parameters were used. Physiological effects were investigated by determination of the percentage of rooting, relative injury rate, root length, and weight gain. Genetic effects were evaluated by the frequency of chromosomal abnormalities (CAs), micronucleus (MN) formation, mitotic index (MI) rate, and comet assay. Biochemical parameters were evaluated with antioxidant enzyme activities and lipid peroxidation by determining malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, catalase (CAT) activity, and glutathione (GSH) level. Also, chlorophyll pigment contents (a, b, and total) in green leaves were calculated to elucidate the effect of diquat dibromide on plants and the biosphere. The findings show that increasing doses of diquat dibromide caused a decrease in all physiological parameters and MI ratio, promoting MN and CAs and tail DNA formation in genetic parameters. It was determined by the increases in MDA level, SOD, and CAT activities and decreases in GSH levels that diquat dibromide administration caused oxidative stress depending on the dose. Also, chlorophyll pigment levels (a, b, and total) measured in leaf tissues decreased with the application dose. Considering that the toxic effects caused by diquat dibromide and that organisms other than unwanted plants will be exposed during the application, its use should be abandoned and biocontrol methods should be used instead. In cases where use is compulsory, doses that will not harm the environment and organisms should be determined and used.

Wastewater-based epidemiology is an innovative approach to estimate a population’s intentional and unintentional consumption of chemicals based on biomarker assays found in wastewater. This method can provide real-time objective information on the xenobiotics to which a population is directly or indirectly exposed. This approach has already been used to assess the population exposure to four classes of pesticides: organochlorines (chlordecone), triazines, organophosphates, and pyrethroids. This review aims to obtain the data (excretion rates) and characteristics (pesticide and metabolites stability, including in-sewer one) for other pesticides to broaden the scope of this new method. Excretion rates and stability descriptions for 14 pesticides, namely 2,4-D, aldrin, carbaryl, chlorobenzilate, dieldrin, diquat, ethion, glufosinate, glyphosate, folpet, malathion, parathion, penconazole, and tebuconazole, will be discussed in a practical framework.

Diquat dibromide (DB) is the active ingredient in several herbicide products used around the world for industrial and recreational control of terrestrial and aquatic pest plants. This study aimed to assess the adverse effects of the commercial formulation of the aquatic herbicide, Reward®, on the Pacific Northwest amphibian species, the northwestern salamander (Ambystoma gracile). Larvae were exposed to the Reward® herbicide in a 96-h acute bioassay (0.37–151.7 mg/L DB) and a continuous 21-day exposure (0.37–94.7 mg/L DB). The 96-h LC₅₀ was 71.5 mg/L and the 21-day LC₅₀ was 1.56 mg/L. Collectively, the results of this study demonstrate that early life stage A. gracile larvae appear largely insensitive to acute Reward® exposures compared to early life stage fish. However, A. gracile larvae are considerably more sensitive during sub-chronic exposure (21 days) with lethal and sub-lethal effects on growth occurring in the 1–2 mg/L range, which more closely resembles the larval fish lethal sensitivity to this active ingredient. This is the first study examining the toxicity of the aquatic herbicide formulation Reward® on A. gracile under acute and sub-chronic exposure scenarios.