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At least 91 records · Page 5Linked to original sources

Loss of pesticides from patches used in the field as pesticide collectors.

Patches of fabrics exposed to pesticide spray formulations lost substantial quantities of the chemicals within four to six hours. Fabrics were cotton or 1:1 cotton-polyester blends, knitted or woven, unfinished or finished. Pesticides used were parathion, malathion, and dicofol. Parathion loss following exposure to spray formulations was dependent on fabric type, finish and their interaction, while a less extensive loss of dicofol depended on none of these. Deposition and retention of pesticide-bearing particulates appeared to depend on mechanical restrictions related to fabric weave and on the electrokinetic potential of fabric surfaces.

Agriculture↗

Sources of pesticides in surface waters in Switzerland: pesticide load through waste water treatment plants--current situation and reduction potential.

Concentrations of pesticides in Swiss rivers and lakes frequently exceed the Swiss quality goal of 0.1 microg/l for surface waters. In this study, concentrations of various pesticides (e.g., atrazine, diuron, mecoprop) were continuously measured in the effluents of waste water treatment plants and in two rivers during a period of four months. These measurements revealed that in the catchment of Lake Greifensee, farmers who did not perfectly comply with 'good agricultural practice' caused at least 14% of the measured agricultural herbicide load into surface waters. Pesticides, used for additional purposes in urban areas (i.e. protection of materials, conservation, etc.), entered surface waters up to 75% through waste water treatment plants.

Agriculture↗

Evaluation of DNA damage in workers occupationally exposed to pesticides using single-cell gel electrophoresis (SCGE) assay. Pesticide genotoxicity revealed by comet assay.

The comet assay, also called the single-cell gel electrophoresis (SCGE) assay, is a rapid and sensitive method for the detection of DNA damage (strand breaks and alkali-labile sites) in individual cells. The assay is based on the embedding of cells in agarose, their lysis in alkaline buffer and finally subjection to an electric current. In the present study, alkaline SCGE was used to evaluate the extent of primary DNA damage and DNA repair in peripheral blood lymphocytes of workers employed in pesticide production. After the period of high pesticide exposure, lymphocytes of the occupationally exposed workers manifested increased tail length and tail moment compared to the control group. After the workers spent 6 months out of the pesticide exposure zone, both endpoints were still above that of the control but significantly decreased as compared to the results of the first analysis.

Adult↗

Report of two co-operative trials of a gel permeation chromatographic method for the isolation of pesticide residues from oils and fats. Committee for Analytical Methods for Residues of Pesticides in Foodstuffs of the Ministry of Agriculture, Fisheries and Food.

A gel permeation chromatographic (GPC) method for the determination of pesticide residues in fats and oils was subjected to two co-operative trials. Results for organochlorine pesticides (beta-HCH, gamma-HCH, dieldrin, p,p'-DDE and heptachlor) were compared with those obtained using an alumina column clean-up method. No significant differences in the mean values were found between the two techniques using the t-test (5% significance level). Horrat values demonstrated acceptable inter- and intralaboratory precisions for both clean-up techniques. Two organophosphorus pesticides (diazinon and propetamphos) and the synthetic pyrethroid deltamethrin were also determined using the GPC method. However, these compounds were not recoverable using the alumina column method, so no comparisons between the two methods were possible.

Chromatography, Gel↗

Evidence for genotoxicity of pesticides in pesticide applicators: a review.

A systematic review of the literature has been conducted and studies reporting investigations of genotoxicity biomarkers in pesticide workers have been assessed with view to establishing whether there was evidence for any risk to those using pesticides approved in the United Kingdom. Each of the studies was evaluated using a set of criteria drawn up by members of the UK Committee of Mutagenicity based upon the guidelines proposed by the International Programme on Chemical Safety (IPCS) working group [R. J. Albertini, D. Anderson, G. R. Douglas, L. Hagmar, K. Hemminki, F. Merlo, A. T. Natarajan, H. Norppa, D. E. Shuker, R. Tice, M. D. Waters and A. Aitio (2000) Mutat. Res., 463, 111-172]; 24 out of 70 studies met the criteria for inclusion in the substantive evaluation. Positive findings were compared with occupational practices and evidence of exposure to specific pesticides with view to developing hypotheses for further consideration. Seventeen of the 24 studies reported positive findings, although in the majority of these the magnitude of increase was small. There was some limited evidence that the use of benzimidazoles was more consistently associated with positive findings. However, limitations in the data, particularly evidence of exposure, did not allow definitive conclusions to be drawn. Also, it was noted that the use (or not) of personal protective equipment (PPE) was not well documented and in the few studies in which its use was reported, the findings were more likely to be positive in the absence of PPE usage. An independent epidemiological review concluded that all studies were of limited design, particularly with regards to study size, the assessment of subject selection and potential recruitment bias. Variance in genotoxicity indices in the control population and a lack of understanding of the factors influencing this variability complicate attempts to characterize positive responses. More substantive data are needed in this respect so that the significance of relatively small increases in biomonitoring indices can be accurately assessed. Once these data are available, a study in workers using benzimidazoles would be appropriate.

Agriculture↗

Biological monitoring of agricultural workers exposed to pesticides: II. Monitoring of intact pesticides and their metabolites.

Analytical methods have been developed for the detection of a variety of compounds that are found intact or as metabolites in biological samples from workers exposed to pesticides. Such tests are used primarily in research settings to describe patterns of absorption, metabolism, and excretion, to derive exposure limits for occupational exposure, to evaluate the adequacy of these limits and of work practices in field settings, and to confirm the etiology of poisonings for medicolegal purposes. We review here methods used in studies of occupational pesticide exposure, with particular attention to validation in terms of dose-response relationships, to technical complexity and cost, to the requirements for analytical quality control, and to the utility of these methods for field research purposes. Biological monitoring for intact pesticides or metabolites in agricultural workers is limited to a few chemicals, notably, pentachlorophenol, methyl bromide, and chlordimeform. These programs and their use in regulation and enforcement are described.

Agricultural Workers' Diseases↗

A study of pesticide safety and health perceptions among pesticide applicators in Tarrant County, Texas.

Pesticide applicators from North Texas participated in a survey that was based on the constructs of the Health Belief Model of Strecher and Rosenstock. The survey assessed the knowledge, beliefs, and self-efficacy of pesticide applicators working for municipalities or in farming/ranching operations in Tarrant County, Texas. It was administered during a continuing-education class on pesticides sponsored by the Texas Agriculture Extension Service in Fort Worth, Texas. Results showed that while knowledge of the use of personal protective equipment was high, knowledge of the risk from dermal exposure was low.

Adult↗

Expanding and tracking the capabilities of pesticide multiresidue methodology used in the Food and Drug Administration's pesticide monitoring programs.

Foods analyzed for pesticide residues in the monitoring programs of the U.S. Food and Drug Administration (FDA) are most often examined by using one or more of the multiresidue methods developed for this purpose over the years. Because no single method can be used for all potential residues, each commodity is examined by a method or methods which will identify and/or determine the chemicals most likely to have been used. FDA conducts research to develop new multiresidue methods, which are included in monitoring programs as needed to cover additional chemicals. FDA's multiresidue methods have undergone continuous study over a 20 year period to ascertain which compounds can and cannot be recovered by them. FDA continues to perform tests to discover a compound's analytical characteristics. Protocols have been published to direct the testing of additional compounds so that new information can be added to the existing compilations. Methods capable of determining residues of single pesticides are used to analyze selected commodities for residues of high priority that cannot be determined by existing multiresidue methods. Pestrak, a computerized listing of pesticide analytical information, has been developed by FDA to keep track of the capabilities of multiresidue methods and the coverage of residues by the single residue methods used in FDA monitoring.

Chromatography, Gas↗

Gas chromatographic relative retention data for pesticides on nine packed columns: II. Organophosphorus and organochlorine pesticides, using electron-capture detection.

The retention time relative to parathion, absolute retention time, concentration range, peak asymmetry factor, and peak shape class are given for each of 42 organophosphorus pesticides and 28 organochlorine pesticides analyzed by gas chromatography (GC) on 9 different packed columns. The packing materials used were 3% SP-2100, 1% Dexsil-300, 3% OV-17, 1.5% OV-17 + 1.95% QF-1, 4% SE-30 + 6% QF-1, 3% OV-17 + 3% OV-210, 5% DC-200 + 7.5% QF-1,3% Carbowax-20M, and 4% Reoplex-400. Retention data were determined at 200 degrees C with a carrier gas flow at uopt, using a 63Ni electron-capture detector. Results should be useful for preliminary identification of environmental samples and also for single or multiple pesticide residue analysis.

Chromatography, Gas↗

[A new programme on safety evaluation of pesticides--the IPCS Joint Meeting on Pesticides (JMP)].

International Programme on Chemical Safety (IPCS), an international collaboration in safety evaluation of chemicals, initiated a programme called Joint Meeting on Pesticides or JMP, last autumn. The JMP is an activity contributing to harmonizing evaluation procedures and saving expertise and financial resources, having several unique features. First, the outputs of the scientific evaluations and data covering all major areas related to pesticide safety in one JMP meeting can be applied to the areas of food safety, occupational health, and environmental protection. Second, succinct presentation of the outputs of reliable evaluations in a tabular form, supported by detailed information in the Environmental Health Criteria documents help people in countries, especially those in developing ones, understand the evaluations and rely on them in establishing their guidelines on pesticide safety. This format of the JMP report is a good example for short assessment reviews on chemicals (Concise International Assessment Document) which will be prepared by an international cooperation project based on Agenda 21 decisions.

Animals↗

Pesticide appliers with mixed pesticide exposure: G-banded analysis and possible relationship to non-Hodgkin's lymphoma.

To further investigate the possible relationships between agricultural pesticide exposure and the increased risk of non-Hodgkin's Lymphoma among farm workers in the north central United States, we performed G-banded chromosome analyses of peripheral blood from workers classified according to primary types of pesticide exposure: herbicides (n = 20), insecticides (n = 18), fumigants (n = 23), and occupationally unexposed controls (n = 33). Significantly increased rearrangement frequencies were demonstrated in fumigant and insecticide appliers compared to control subjects. At certain chromosome bands there were significant excesses of breaks observed in pesticide appliers, but no breaks were observed in controls. Some of these bands contained genes with potential implications for cancer risk, including oncogenes and genes involved in tumor suppression and apoptosis. Of particular interest with regard to lymphoma risk were the excess rearrangement and breaks involving band 14q32 in fumigant appliers and the excess breaks involving band 18q21 in herbicide appliers; translocations linking 14q32 and 18q21 are the most common rearrangements observed in non-Hodgkin's lymphoma patients. The potential pathobiological relevance of these cytogenetic events warrants additional investigation at the molecular level.

Agricultural Workers' Diseases↗

Organochlorine pesticides and enantiomers of chiral pesticides in Arctic Ocean water.

In the summers of 1993 and 1994, seawater samples from the surface layer (40-60 m) were collected to determine the spatial distribution of organochlorine pesticides on expeditions that crossed the Arctic Ocean from the Bering and Chukchi seas to the North Pole, to a station north of Spitsbergen, and then south into the Greenland Sea. Spatial differences in concentration were found that varied with the pesticide. Heptachlor exo-epoxide (a metabolite of heptachlor) and alpha-hexachlorocyclohexane (alpha-HCH) increased from the Chukchi Sea to the pole, and then decreased toward Spitsbergen and Greenland Sea. Chlorinated bornanes (toxaphene) followed a similar trend, but levels were also high near Spitsbergen and in the Greenland Sea. A reverse trend was found for endosulfan, with lower concentrations in the ice-covered regions. Little variation was seen in chlordane concentrations, although the ratio of trans-/cis-chlordane decreased at high latitudes. Several of these pesticides are chiral: alpha-HCH, cis- and trans-chlordane, and heptachlor exo-epoxide. Enantioselective degradation of (-)alpha-HCH was found in the Bering and Chukchi seas, whereas the (+)enantiomer was depleted in the Arctic Ocean and Greenland Sea. Enrichment of (+)heptachlor exo-epoxide was found in all regions. Trans- and cis-chlordane were nearly racemic.

Arctic Regions↗

Effect of pesticide mixtures on in vitro nervous cells: comparison with single pesticides.

The toxicity of dimethoate, azinphos-methyl, diazinon, pirimiphos methyl, organophosphorus insecticides, and benomyl (a benzimidazole fungicide) singly and in mixture was studied in a human neuroblastoma cell line, SH-SY5Y. The cells were incubated for 30 min and 4 h with pesticides at concentrations ranging from 0.4 to 100 micrograms/ml, or with the same compounds mixed as follows: (a) dimethoate-diazinon-azinphos; (b) benomyl-pirimiphos; (c) all together. Pesticides in the mixtures were at the same concentration used when tested singly. Diazinon, azinphos-methyl and pirimiphos, but not dimethoate and benomyl, inhibited acetylcholine esterase (AchE) activity, whereas all the compounds inhibited protein synthesis in the following order: benomyl > azinphos > diazinon >> pirimiphos = dimethoate. The mixtures showed a toxicity on AchE activity at a maximum equal to that of the most active compound in the mixture. On the contrary, the mixture were more toxic than the single compounds on protein synthesis, and in certain cases potentiation occurred. Therefore, we can conclude that it is not feasible to predict the toxicity of pesticide mixtures on the basis of the results of the toxicity of single components.

Acetylcholinesterase↗

[The effect of pesticide combinations on laboratory rats. I. Determination of the acute oral toxicity (LD50) of pesticide combinations].

The growing use of a diversity of pesticides in agricultural practice calls for studies into the toxicity of pesticides when used in combinations. Fundamental studies were conducted into the acute toxicity of pesticide combinations in rat and showed that double or triple combinations of parathion-methyl, carbaryl, and Lindan could aggravate or mitigate toxicity, depending on the active ingredients involved. The above findings were obtained from acute animal experiments, but it may well be necessary to develop proper screening models for optimum information and to study subchronic toxicity as well.

Animals↗

Detection of pesticides and pesticide metabolites using the cross reactivity of enzyme immunoassays.

Enzyme immunoassay is an important environmental analysis method that may be used to identify many pesticide analytes in water samples. Because of similarities in chemical structure between various members of a pesticide class, there often may be an unwanted response that is characterized by a percentage of cross reactivity. Also, there may be cross reactivity caused by degradation products of the target analyte that may be present in the sample. In this paper, the concept of cross reactivity caused by degradation products or by nontarget analytes is explored as a tool for identification of metabolites or structurally similar compounds not previously known to be present in water samples. Two examples are examined in this paper from various water quality studies. They are alachlor and its metabolite, alachlor ethane sulfonic acid, and atrazine and its class members, prometryn and propazine. A method for using cross reactivity for the detection of these compounds is explained in this paper.

Acetamides↗

Pesticide illness surveillance: review of the National Pesticide Hazard Assessment Program.

Regarding consultations on pesticide exposures by Oregon State University, the following information is summarized: 1) source of queries; 2) locations of exposure; 3) types of chemicals; and 4) nature of the illnesses. The majority of queries involve nonagricultural exposures in the home and workplace. Principal sources of referral are from the National Pesticide Telecommunications Network (toll-free number), state departments of agriculture, and state extension services. In addition to illnesses, the system also responds to press releases such as those that occurred after the withdrawal of chlordane. Previously unsuspected clinical problems have been reported (suggesting new areas of research need), including cases associated with long-acting organophosphates, such as chlorpyrifos, and with the pyrethroids.

Adult↗

Importance of considering pesticide stereoisomerism--proposal of a scheme to apply Directive 91/414/EEC framework to pesticide active substances manufactured as isomeric mixtures.

An important gap has been detected in the application of the European framework for the evaluation of pesticide active substances constituted by enantiomeric and other kind of stereoisomeric mixtures. Up to date, little attention has been paid to the different biological properties of these compounds. Considering efficacy, toxicity, environmental fate and behaviour and ecotoxicity of separated isomers is necessary to fulfil Directive 91/414/EEC objectives of health and environment protection. Here, a critical review of this question for pesticide active substances is presented. An evaluative scheme for considering this question in the framework of Directive 91/414/EEC is also proposed.

European Union↗

Interactions between pesticides and components of pesticide formulations in an in vitro neurotoxicity test.

Organophosphate (OP) pesticides are often used in combination with one another and with the components of formulations. Evidence already exists for interactions in the neurotoxic effects of OPs through interference with metabolism, but there is also potential for interactions related directly to cell damage. The purpose of this work was to investigate this possibility for OPs and the components of one of their common formulations in vitro. NB2a neuroblastoma cells were induced to differentiate in the presence of the OPs diazinon and chlorpyrifos, in combination with a commercial formulation (identified as Commercial Formulation 1) of the compounds and, independently, the components of that formulation. The compounds were tested in pairs in various proportions and the resulting inhibition of neurite outgrowth was measured by light microscopy and quantitative image analysis. Interactions were determined in terms of enhanced or reduced effects of the paired compounds in comparison with the expected additive effects estimated from the effects of each compound on its own. Synergism was detected between combinations of: 10 microM chlorpyrifos and 500 nM pyrethrum; chlorpyrifos and one of the solvents (regular spirit) found in Commercial Formulation 1. All other combinations of OPs and products were additive in their neurotoxicity. The data suggest that exposure to multiple OP-containing pesticide formulations may lead to synergistic neurotoxicity by a direct mechanism at the cellular level.

Animals↗