Estimating half-lives of pesticides in/on vegetation for use in multimedia fate and exposure models

Degradation half-lives in/on vegetation are needed in environmental risk assessment of pesticides, but these data are often not available for most active ingredients. To address this, we first correlated experimental soil degradation half-life data of 41 pesticides obtained from the reviewed literature with the corresponding experimental half-lives on plant surface. Degradation half-lives in soil were found to be four times slower compared with half-lives on plant surfaces. In a second step, we explored measured plant surface half-lives directly with those in vegetation. The results were validated by comparing computed values with results obtained from an experimental set-up. The uptake and dissipation of alpha-cypermethrin (insecticide) and bromopropylate (acaricide) was studied by detecting pesticide residues in whole and peeled tomato fruits using gas chromatography. Half-lives within vegetation were found to be four times faster compared with plant surface half-lives. Using this experimental based approach, it is concluded that the estimation of degradation half-lives of pesticides in/on vegetation to be used as input data in environmental mass balance models can be directly correlated from the more abundant ready experimental degradation half-life data for soil.     

Biodegradability assessment of several priority hazardous substances: choice, application and relevance regarding toxicity and bacterial activity

Nineteen compounds listed in the category of priority substances (PS) were selected for a biodegradation study using standardized tests. The compounds consist of pesticides, chlorinated solvents and volatile organic compounds (VOCs). In this paper, the choice of the most suitable method is discussed in relation to the physico-chemical properties of each substance. Zahn-Wellens, manometric respirometry and closed-bottle tests are alternatively used. Experimental results are presented and interpreted. Toxicity (Microtox) and bacterial viability (Bac-light) are also used as tools to investigate the influence of each substance on the microbial population (activated sludge). In addition, experimental values are compared with predictive data calculated according to quantitative structure activity relationships (QSARs) models. Biodeg Models were permitted to correctly estimate 17 substances; Survey Models and screening tests also revealed the same behavior for 16 target compounds.     

The excretion of pesticides in saliva and its value in assessing exposure

The possibility that pesticides are secreted in the saliva and that this secretion can be used to assess exposure to pesticides is discussed. Both Kepone and carbaryl were tested through a series of in vitro studies and in vivo experiments including both acute and subchronic studies. In the in vivo studies, both Kepone and carbaryl were detected in the saliva in the first twenty-four hours, but seldom thereafter. Analysis of urinary samples indicated a rapid clearance of the substances from the animals. In vitro uptake and efflux studies suggested that movement of both substances was by passive diffusion and reached a plateau after 60 minutes of incubation. Efflux rates were unaffected by experimental conditions, but were ten times faster for carbaryl.     

Statute and legislative history of the federal insecticide,fungicide, and rodenticide act and its impact on agriculture

Abstract

This report discusses the responsibilities of government for the legislation of pesticides, and describes the impact of various statutes on the use of pesticides in agriculture. Governmental responsibilities for management of the economy, education, and enactment of laws and regulations are discussed, and the history of U.S. legislation of pesticides and related substances is presented. Finally, the impact of pesticide regulation on international trade is considered.     

Impact of long-term pesticide applications on some soil biological parameters

The soil oxidative and anaerobic processes, as well as, the microbial biomass were followed during three years in a cotton farm (Tatuí) where the recommended pesticides have been used for several years, and in an experimental field (S?o Paulo) treated first time with the same pesticides. The oxidative process was monitored by the dehydrogenase (DHA)-activity using triphenyltetrazolium chloride (TTC) as substrate. The anaerobic process was followed by the iron-oxide reduction, and the microbial biomass was estimated by the substrate (glucose)-indiced respiration. Increases in DHA-activity and in the microbial biomass occurred only in the farm soil, with concomitant decreases in iron-reduction. In the experimental field soil, the increases in DHA-activity were followed only by decreases in iron-reduction. Soil characteristics were the determining factor for different biological parameters after pesticide inputs. All the pesticides produced at least one clear but transient effect.     

Determining the role of human substances in the fate of pesticides in the environment

The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV-radiation, are described. Finally, the photochemical stability to UV-radiation of certain pesticides in aqueous fulvic acid solution is discussed.     

Comparison of atmospheric concentrations of currently used pesticides between urban and rural areas during intensive application period in Alsace (France) by using XAD-2® based passive samplers

XAD-2® passive samplers (PAS) have been exposed simultaneously for 14 days on two sites, one rural and one urban, situated in Alsace (East of France) during intensive pesticides application in agriculture (between March and September). PAS have been extracted and analyzed for current-used pesticides and lindane with an analytical method coupling accelerated solvent extraction (ASE), solid-phase microextraction (SPME) and GC/MS/MS. Results show the detection of pesticides is linked to the period of application and spatial and temporal variabilities can be observed with these PAS during the selected sampling period. The spatial and temporal variability is comparable to the one previously observed by comparing data obtained with PAS with data from Hi.-Vol. samplers in an urban area. Sampling rates were calculated for some pesticides and values are comparable to the data already available in the literature. From these sampling rates, concentrations in ng m^?3 of pesticides in PAS have been calculated and are in the same order of magnitude as those obtained with Hi.Vol. sampling during the same period of time.     

Determining the role of humic substances in the fate of pesticides in the environment

Abstract

The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV‐radiation, are described. Finally, the photochemical stability to UV‐radiation of certain pesticides in aqueous fulvic acid solution is discussed.     

Impact of long‐term pesticide applications on some soil biological parameters

Abstract

The soil oxidative and anaerobic processes, as well as, the microbial biomass were followed during three years in a cotton farm (Tatuí) where the recommended pesticides have been used for several years, and in an experimental field (São Paulo) treated first time with the same pesticides. The oxidative process was monitored by the dehydrogenase (DHA)‐activity using triphenyltetrazolium chloride (TTC) as substrate. The anaerobic process was followed by the iron‐oxide reduction, and the microbial biomass was estimated by the substrate (glucose)‐indiced respiration. Increases in DHA‐activity and in the microbial biomass occurred only in the farm soil, with concomitant decreases in iron‐reduction. In the experimental field soil, the increases in DHA‐activity were followed only by decreases in iron‐reduction. Soil characteristics were the determining factor for different biological parameters after pesticide inputs. All the pesticides produced at least one clear but transient effect.     

Bioassay-directed chemical analysis of River Elbe surface water including large volume extractions and high performance fractionation

A bioassay-directed fractionation and identification (toxicity identification evaluation procedure) was performed on extracts of 10 1 River Elbe water samples. The experimental method included a SDB-1 solid phase extraction followed by RP-HPLC fractionation and subfractionation. Chemical analysis by GC-MS as well as acute toxicity testing using a luminescent bacteria assay were conducted in the respective fractions. Many substances were identified, among which were pesticides and pharmaceuticals, but many compounds remained unknown.     

Obsolete pesticides and application of colonizing plant species for remediation of contaminated soil in Kazakhstan

In Kazakhstan, there is a problem of finding ways to clean local sites contaminated with pesticides. In particular, such sites are the deserted and destroyed storehouses where these pesticides were stored; existing storehouses do not fulfill sanitary standards. Phytoremediation is one potential method for reducing risk from these pesticides. Genetic heterogeneity of populations of wild and weedy species growing on pesticide-contaminated soil provides a source of plant species tolerant to these conditions. These plant species may be useful for phytoremediation applications. In 2008–2009 and 2011, we surveyed substances stored in 80 former pesticide storehouses in Kazakhstan (Almaty oblast) to demonstrate an inventory process needed to understand the obsolete pesticide problem throughout the country, and observed a total of 354.7 t of obsolete pesticides. At the sites, we have found organochlorine pesticides residues in soil including metabolites of dichlorodiphenyltrichloroethane and isomers of hexachlorocyclohexane. Twenty-four of the storehouse sites showed pesticides concentrations in soil higher than maximum allowable concentration which is equal to 100 μg kg^?1 in Kazakhstan. Seventeen pesticide-tolerant wild plant species were selected from colonizing plants that grew into/near the former storehouse’s pesticides. The results have shown that colonizing plant annual and biannual species growing on soils polluted by pesticides possess ability to accumulate organochlorine pesticide residues and reduce pesticide concentrations in soil. Organochlorine pesticides taken up by the plants are distributed unevenly in different plant tissues. The main organ of organochlorine pesticide accumulation is the root system. The accumulation rate of organochlorine pesticides was found to be a specific characteristic of plant species and dependent on the degree of soil contamination. This information can be used for technology development of phytoremediation of pesticide-contaminated soils.     

Predicting logP of pesticides using different software

We compared experimental and calculated logP values using a data set of 235 pesticides and experimental values from four different sources: The Pesticide Manual, Hansch Manual, ANPA and KowWin databases. LogP were calculated with four softwares: HyperChem, Pallas, KowWin and TOPKAT. Crossed comparison of the experimental and calculated values proved useful, especially for pesticides. These are harder to study than simpler organic compounds. Structurally they are complex, heterogeneous and similar to drugs from a chemical point of view. They offer an interesting way to verify the goodness of the different methods. Other studies compared several logP predictors using a single set of experimental values taken as a reference. Here we discuss the utility of the different logP predictors, with reference to experimental data found in different databases. This offers three advantages: (1) it avoids bias due to the assumption that one single data set is correct; (2) a given predictor can be developed on the same data set used for evaluation; (3) it takes account of experimental variability and can compare it with the predictor's variability. In our study Pallas and KowWin gave the best results for prediction, followed by TOPKAT.     

Official control of plant protection products in Poland: detection of illegal products

Market presence of illegal and counterfeit pesticides is now a global problem. According to data published in 2012 by the European Crop Protection Association (ECPA), illegal products represent over 10% of the global market of plant protection products. Financial benefits are the main reason for the prevalence of this practice. Counterfeit and illegal pesticides may contain substances that may pose a threat to the environment, crops, animals, and humans, inconsistent with the label and registration dossier. In Poland, action against illegal and counterfeit plant protection products is undertaken by the Main Inspectorate of Plant Health and Seed Inspection (PIORiN), the police, the prosecution, and the pesticide producers. Results of chemical analyses carried out by the Institute of Plant Protection - National Research Institute So?nicowice Branch, Pesticide Quality Testing Laboratory (PQTL IPP-NRI Sosnicowice Branch) indicate that a majority of illegal pesticides in Poland are detected in the group of herbicides. Products from parallel trade tend to have the most irregularities. This article describes the official quality control system of plant protection products in Poland and presents the analytical methods for testing pesticides suspected of adulteration and recent test results.     

Pestizide im Tabakrauch II. Pyrolyseverhalten von ausgewählten pestiziden beim Tabakrauchen

The fate of Lindan, DDT, Malathion, Monolinuron, Captan and Maneb during smoking process was studied and it was observed that the amount of unchanged pesticides in the mainstream smoke depends on steam volatility of the substances, while the vapor pressures have no significant influence.     

Determination photostability of selected agrochemicals in water and soil.

The photolysis of selected pesticides in aqueous solutions has been investigated. The photolysis produced different intermediate substances, which were also found to be soil and microbial degradation products. The phototransformation in the presence of TiO2 and humic substances leads to a disappearance of these compounds. The reaction rate is dependent on the semiconductor oxide and concentration. Photoproducts were isolated and characterized by different spectroscopic methods. Results from this study indicate that degradation products of isoproturon are more toxic on Daphnia magna than on the parent compound.     

Multidimensional gas chromatographic enantiomer quantification of some chlorinated xenobiotics in cod liver and fish oils.

Four chiral HRGC column systems for the separation of selected organochlor pesticides and photoconversion products (heptachlor, cis- and trans-chlordane, o,p'-DDT, o,p'-DDD, and alpha-HCH) were tested. Cod hver oil and fish oil samples from different countries were comparatively analyzed. Of all these columns, the fourth was the most suitable one for the analysis of the selected compounds. The enantiomer ratios [ER] of cis-chlordane, trans-chlordane, photodieldrin, alpha-HCH, and o,p'-DDD in fish oils are nearly 1.0, while the ERs of the same substances are significantly different from 1.0 in cod liver oils. Contrary to that, the ER values of o,p'-DDT are remarkable different from 1 in the cod liver oils as well as in the fish oils.     

Effect of clarification process on the removal of pesticide residues in red wine and comparison with white wine

The aim of this study was to determine the potential of seven clarifying agents to remove pesticides in red wine. The presence of pesticides in wine consists a great problem for winemakers and therefore, results on pesticide removal by clarification are very useful for taking a decision on the appropriate adsorbent. The selection of an efficient adsorbent can be based on data correlating pesticide removal in red wine to pesticides' properties, given the great number and variety of pesticides used. So, this experimental work is focused on the collection of results with regard to pesticide removal by clarification using a great number of pesticides and fining agents. A Greek red wine, fortified with single solutions and mixtures of 23 or 9 pesticides was studied. The seven fining agents, used at two concentrations, were activated carbon, bentonite, polyvinylpolypyrrolidone (PVPP), gelatin, egg albumin, isinglass-fish glue, and casein. Pesticides were selected with a wide range of properties (octanol–water partition coefficient (log K_ow) 2.7–6.3 and water solubility 0.0002–142) and belong to 11 chemical groups. Solid phase extraction (SPE) followed by gas chromatography (GC) with electron capture detector (ECD) were performed to analyze pesticide residues of the clarified fortified wine. The correlation of the clarifying agents' effectiveness to pesticide's chemical structure and properties (log K_ow, water solubility) was investigated. The antagonistic and/or synergistic effects, occurring among the pesticides in the mixtures, were calculated by indices. Pesticide removal effectiveness results of the red wine were compared to those obtained from a white wine under the same experimental conditions and discussed. The order of decreasing adsorbent effectiveness (mixture of 23 pesticides) was: activated carbon 40% > gelatin 23% > egg albumin 21% > PVPP 18% > casein 12% > bentonite 7%. Isinglass showed 12% removal at the highest permitted concentration. In the case of 9 pesticides mixture, the effectiveness was quite higher but the order remained the same compared to 23 pesticides mixture. The removal of each pesticide from its single solution was generally the highest (particularly for hydrophobic pesticides). Adsorption on fining agents is increased by increasing hydrophobicity and decreasing hydrophilicity of organic pesticide molecules.     

Degradation of nitrogen containing organic compounds by combined photocatalysis and ozonation

The combination of TiO2-assisted photocatalysis and ozonation in the degradation of nitrogen-containing substrates such as alkylamines, alkanolamines, heterocyclic and aromatic N-compounds has been investigated. A laboratory set-up was designed and the influence of the structure of the N-compound, the TiO2 and ozone concentration on the formation of breakdown products were examined. The experimental results showed that a considerable increase in the degradation efficiency of the N-compounds is obtained by a combination of photocatalysis and ozonation as compared to either ozonation or photocatalysis only. The mineralization of the model substances was monitored by measurements of the TOC and ion-chromatographic determinations of the formed NO2- and NO3-. The temporal changes of concentrations of breakdown products, such as NH4+, short chain alkyl- and alkanolamines were determined by single column ion chromatography (SCIC) and as well as by electrospray mass spectrometry (EI-MS).     

Toxicity of pesticides toward human immune cells U-937 and HL-60

Abstract

The industrialization of the agricultural sector has significantly increased the use of chemicals such as pesticides. Therefore, exposure to them is unavoidable, which makes it necessary to assess their safety for humans at actual exposure doses. This paper aims to determine toxicity of three types of pesticides toward human immune cells (HL-60 and U-937): glyphosate (GLY), deltamethrin (DEL), and chlorothalonil (CHL). Cell viability, membrane integrity, inflammation induction, and antioxidant activity were evaluated to determine differences in cellular response to the tested plant protection agents. In experimental models, all tested substances caused increased mortality of cells after only 24?h. Cell membrane damage was recorded under DEL and CHL influences. The largest disintegration of the cell membrane was due to the action of 100?μg/mL DEL for U-937 and CHL at 1?μg/mL for HL-60. GLY at a concentration of 3,600?μg/mL caused significant peroxidation of U-937 cells’ lipids. CHL-induced inflammation in both types of cells tested. DEL and GLY also induced antioxidant activity in cells. These results lead to the conclusion that the tested pesticides act cytotoxically to the cells of the human immune system in doses to which both farmers and consumers are exposed.     

多相催化-臭氧氧化法处理模拟有机磷农药废水

实验通过臭氧氧化法来降解模拟废水中的有机磷农药,将其转化为无害物质,并试验研究了在废水中加入2种自制的催化剂对降解结果的影响。采用气相色谱法测定水中有机磷农药的量。结果表明,只用臭氧处理的情况下1周后有机磷的去除率为78.03%;在催化剂A存在下,去除率可达93.85%;在催化剂B存在下,去除率可达为88.35%。结果表明,臭氧氧化法对此类污水具有较好的降解作用,尤其在有催化剂存在的情况下处理效果更好,在室温和中性介质中均属于一级反应。