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A two-year field study (2001-2002) was carried out in N-W Italy to study the behaviour of pretilachloi [2-chloio-2,6-diethyl-N-(2-propoxyethyl)acetanilide] in water and sediment of a rice field. Pretilachlor is a selective pre-eme...
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A two-year field study (2001-2002) was carried out in N-W Italy to study the behaviour of pretilachloi [2-chloio-2,6-diethyl-N-(2-propoxyethyl)acetanilide] in water and sediment of a rice field. Pretilachlor is a selective pre-emergence herbicide which is effective against annual grasses, sedges and broad-leaved weeds. The herbicide was applied in pre-seeding on a flooded rice field where water circulation was stopped for about 3 weeks after treatment. Pretilachloi concentration in the paddy water decreased by more than 90% during the first three weeks after the treatment. The amount of the herbicide in the paddy water gradually fell to levels below the sensitivity of the analytical method when water circulation was re-established The pretilachlor concentration in the sediment gradually increased after the treatment, reaching the highest value 5 to 6 days later. The average DT_(50) in water and sediment were 6,77 and 28.76 days in 2001, 4.68 and 15.01 days in 2002, respectively. The low percolationrate (0,95 and 0,79 mm day~(-1) in 2001 and 2002, respectively) and the high ratio of the herbicide adsorption on the sediment suggest that pretilachlor disappearance from the water was mainly the result of degradation,
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Bayluscide is an additive to TFM that increases the effectiveness of TFM as a lampricide. A review of the literature was undertaken to determine the environmental fate and effects of Bayluscide. Niclosamide (2′, 5-dichloro-4′-ni...
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Bayluscide is an additive to TFM that increases the effectiveness of TFM as a lampricide. A review of the literature was undertaken to determine the environmental fate and effects of Bayluscide. Niclosamide (2′, 5-dichloro-4′-nitrosalicylanilide), the active ingredient of Bayluscide, degrades rapidly in natural water and sediment systems, however, the rate of degradation is very slow in autoclaved samples. This difference suggests that degradation under laboratory conditions is dependent on microbial activity and hydrolysis plays a minor role in degradation of niclosamide. The major degradation product of niclosamide has been reported to be aminoniclosamide (2′,5-dichloro-4′-aminosalicylanilide), which represented more than 50% of the residues extractable from sediments. Significantly more of the chemical is adsorbed to sediments with higher organic content and at lower pH's. The mobility of niclosamide in soil can be characterized as slight to medium; the estimated leaching distance would range from 0 to > 25 cm depending on the soil type and pH. The active ingredient of Bayluscide (niclosamide) is decomposed by ultra-violet light depending on the intensity and duration of the exposure. The uptake of residues by most invertebrates exposed to ~(14)C-niclosamide is fairly rapid and equilibrium is reached within 24 h. About 90% of the accumulated residues were lost within 48 h after the organisms were transferred to clean flowing water. As with invertebrates, fish rapidly accumulate and eliminate residues of niclosamide. Three distinct residues were isolated from the extracts of edible fillet tissue; parent niclosamide, the glucuronide conjugate of niclosamide, and the sulfate ester of niclosamide. Aquatic plants and agricultural crops do not appear to be adversely affected at concentrations of Bayluscide used for lamprey or snail control. Mayflies (Hexagenia sp.). tend to be susceptible to TFM, but are relatively resistant to the effects of exposure to Bayluscide. Bayluscide was originally developed as a molluscicide to eliminate snails. Therefore, it is not surprising that mollusks are extremely sensitive to Bayluscide. Oral, dermal, and ocular administration of Bayluscide to mammals resulted in no clinical signs of systemic toxicity. Tests of the chronic effects of Bayluscide indicated that it is not mutagenic or carcinogenic. Bayluscide is not persistent in the environment; it breaks down in natural water and sediment systems through hydrolysis, photolysis, and microbial degradation. Given the limited use and tight control maintained by the U.S. Fish and Wildlife Service during applications of lampricides, Bayluscide presents minimal risk to human health and safety of the environment.
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The author critically reviewed existing researches on soil-plant transfer coefficients or soil-plant relation equations for environmental fate model that estimating transferring metals and metalloids. Although soil-plant relation ...
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The author critically reviewed existing researches on soil-plant transfer coefficients or soil-plant relation equations for environmental fate model that estimating transferring metals and metalloids. Although soil-plant relation equations were available for some crops, the equations on staple foods for Japanese were not existed. Soil factors affecting phytoavailability were critically reviewed. Metal concentration in soil, pH in soil, organic carbon contents in soil, and cation exchange capacities (CECs) in soil were often used for dependant variables of soil-plant relation equations, however, another factors should play an important role for explaining variance. Finally, as for a case study, the factors that affect soil-rice transfer of cadmium (Cd) were analyzed. Results showed that a difference of water management condition in a paddy field was a critical factor. The soil-plant relation equation including water management condition successfully estimated Cd concentration in rice from Cd concentration in soil, pH in soil and CECs in soil.
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Glyphosate herbicides are widely relied upon by European railway operators for controlling vegetation growing on railway tracks. In Sweden, concentrations of glyphosate and its main degradation product AMPA have been monitored in ...
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Glyphosate herbicides are widely relied upon by European railway operators for controlling vegetation growing on railway tracks. In Sweden, concentrations of glyphosate and its main degradation product AMPA have been monitored in the groundwater close to railways during two monitoring periods: between 2007-2010 and 2015-2019. In total, 603 groundwater samples from 12 different monitoring sites and 645 soil samples from 5 of these sites were analyzed. Glyphosate and AMPA were detected in 16% and 14%, respectively, of groundwater samples taken from directly beneath the track, with concentrations exceeding the EU groundwater quality standard of 0.1 μg/L in 6 and 4% of the cases, respectively. The highest concentrations detected in single samples were 7 μg glyphosate/L and 1.1 μg AMPA/L. However, further horizontal spread in the groundwater zone appeared to be limited as glyphosate and AMPA were only detected in 1-3% of the groundwater samples taken from outside the track area itself, and since no difference was seen between water from reference and down-gradient wells. In the autumn of 2018, higher concentrations were detected in the groundwater from beneath 3 out of the 5 then active monitoring sites and a possible explanation is that the unusually hot and dry summer of 2018 limited degradation, thus leading to an increased susceptibility of leaching. The contents of glyphosate and AMPA in soil samples from three of the sites were very low (average ＜ 0.05 mg/kg in soil from 0 to 30 cm), indicating that they were only sprayed to a limited degree, whereas the contents from two of the test sites were in line with what would be expected based on the used dose and a predicted half-life of about 4 ± 2 months (average 0.22-0.84 mg/kg). No signs of accumulation of glyphosate in the railway ballast over time were observed.
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Nanopesticides or nano plant protection products represent an emerging technological development that, in relation to pesticide use, could offer a range of benefits including increased efficacy, durability, and a reduction in the ...
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Nanopesticides or nano plant protection products represent an emerging technological development that, in relation to pesticide use, could offer a range of benefits including increased efficacy, durability, and a reduction in the amounts of active ingredients that need to be used. A number of formulation types have been suggested including emulsions (e.g., nanoemulsions), nanocapsules (e.g., with polymers), and products containing pristine engineered nanoparticles, such as metals, metal oxides, and nanoclays. The increasing interest in the use of nanopesticides raises questions as to how to assess the environmental risk of these materials for regulatory purposes. Here, the current approaches for environmental risk assessment of pesticides are reviewed and the question of whether these approaches are fit for purpose for use on nanopesticides is addressed. Potential adaptations to existing environmental risk assessment tests and procedures for use with nanopesticides are discussed, addressing aspects such as analysis and characterization, environmental fate and exposure assessment, uptake by biota, ecotoxicity, and risk assessment of nanopesticides in aquatic and terrestrial ecosystems. Throughout, the main focus is on assessing whether the presence of the nanoformulation introduces potential differences relative to the conventional active ingredients. The proposed changes in the test methodology, research priorities, and recommendations would facilitate the development of regulatory approaches and a regulatory framework for nanopesticides.
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The fate of thiodiglycol (TDG) in environmental samples was studied through analysis of batch solid-solution suspen- Sions. We monitored aqueous-phase TDG concentrations and thiodiglycolic acid (TGDA) concentrations by high-perfor...
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The fate of thiodiglycol (TDG) in environmental samples was studied through analysis of batch solid-solution suspen- Sions. We monitored aqueous-phase TDG concentrations and thiodiglycolic acid (TGDA) concentrations by high-performance liquid Chromatography with ultravoilet detection. We investigated TDG and TDGA sorption to six soils. Thiodiglycol sorption was Insignificant, with a maximum sorption capacity of less than 10 mg/kg. Sorption of TDGA varied, with maximum sorption capacities Ranging form 19.9 to 427.4 mg/kg.
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The objective this study was to monitor pesticide residues in groundwater at three different times and in seven regions producing rice in southern Brazil, in the 2007/08 season. Imazethapyr and fipronil were found in all regions s...
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The objective this study was to monitor pesticide residues in groundwater at three different times and in seven regions producing rice in southern Brazil, in the 2007/08 season. Imazethapyr and fipronil were found in all regions studied. All groundwater samples from the Planicie Costeira Interna to Lagoa dos Palos and Santa Catarina contained at least one pesticide. The lowest number of contaminated samples were detected in the Southern region. The highest frequency of contaminated samples was found after drainage of the rice fields. Only fipronil exceeded limits of potability, in 27% of samples, according European Community criteria.
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Raloxifene hydrochloride is a selective estrogen receptor modulator(SERM) used for the prevention and treatment of osteoporosis in women. Excretion of raloxifene occurs through the feces of patients. Raloxifiene has the potential ...
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Raloxifene hydrochloride is a selective estrogen receptor modulator(SERM) used for the prevention and treatment of osteoporosis in women. Excretion of raloxifene occurs through the feces of patients. Raloxifiene has the potential to be discharged into waste treatment systems after therapeutic use. Raloxifene hydrochloride was investigated using a battery of studies designed to describe its physical/chemical characteristics and define its fate in the environment. The mean measured solubility of raloxifene hydrochloride(± standard deviation) was 345.2±15.6μg/ml, 13.3±0.6μg/ml, 0.9224±0.015 μg/ml, and 627.4±132.0μg/ ml in aqueous buffers at pH 5, 7, and 9 and in unbuffered water, respectively.
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Thermally synthesized polyaspartate (TPA, AmiSorb) is marketed as a crop growth enhancer. However, the stability and adsorption of this product in soils have not been fully evaluated. In this study, microbial degradation of TPA wa...
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Thermally synthesized polyaspartate (TPA, AmiSorb) is marketed as a crop growth enhancer. However, the stability and adsorption of this product in soils have not been fully evaluated. In this study, microbial degradation of TPA was determined in 10 different soils using C-14- labeled TPA. Biodegradation, measured as mineralization (CO2 production), varied with soil type ranging from 2.15% for a Hort Mix to 32.05% for the Pullman soil after 35 days incubation under the defined conditions. Percentages of degradation also varied with concentrations of the applied TPA. In most of the soils evaluated, TPA degradation rates were higher at 100 mug g(-1) than at 2 or 10 mug g(-1) after 35 days of incubation. In general, C and N supplements, as primary nutrients for microbial growth, reduced mineralization, suggesting that the level of readily available macronutrients in the soil influenced TPA utilization. Biodegradation of TPA was highly correlated with soil pH but was not correlated with any other soil parameters measured in this study, including Kd. The Kd values of the tested soils for TPA ranged from 10.6 to 98.8 mL g(-1) for the Norfolk and Bolfar soils, respectively.
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One of the more effective ways of managing high densities of adult mosquitoes that vector human and animal pathogens is ultra-low-volume (ULV) aerosol applications of insecticides. The U.S. Environmental Protection Agency uses mod...
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One of the more effective ways of managing high densities of adult mosquitoes that vector human and animal pathogens is ultra-low-volume (ULV) aerosol applications of insecticides. The U.S. Environmental Protection Agency uses models that are not validated for ULV insecticide applications and exposure assumptions to perform their human and ecological risk assessments. Currently, there is no validated model that can accurately predict deposition of insecticides applied using ULV technology for adult mosquito management. In addition, little is known about the deposition and drift of small droplets like those used under conditions encountered during ULV applications. The objective of this study was to perform field studies to measure environmental concentrations of insecticides and to develop a validated model to predict the deposition of ULV insecticides. The final regression model was selected by minimizing the Bayesian Information Criterion and its prediction performance was evaluated using k-fold cross validation. Density of the formulation and the density and CMD interaction coefficients were the largest in the model. The results showed that as density of the formulation decreases, deposition increases. The interaction of density and CMD showed that higher density formulations and larger droplets resulted in greater deposition. These results are supported by the aerosol physics literature. A k-fold cross validation demonstrated that the mean square error of the selected regression model is not biased, and the mean square error and mean square prediction error indicated good predictive ability.
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