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PubMed1992

Codex Committee on Pesticide Residues--a plan for improved participation by governments.

The Codex Committee on Pesticide Residues (CCPR), which is responsible for establishing maximum residue limits (MRLs) for pesticides on food, has a vital role in protecting the public health and facilitating international trade. Codex MRLs are based on scientific evaluations by expert panels that constitute the Joint FAO/WHO Meeting on Pesticide Residues (JMPR). These panelists estimate an acceptable daily intake for a pesticide and expected level of residue remaining in food when the pesticide is used according to good agricultural practice. The goals of the CCPR are not being fully achieved. Governments are generally not accepting Codex MRLs; instead, technical and procedural aspects of the JMPR and CCPR process are being criticized. The CCPR is responding to valid criticisms of the process; however, governments may still lack the will to seek harmonization of pesticide limits for food in international trade. Overcoming this problem will be difficult, but not impossible. A plan of action is proposed that allows countries to selectively accept Codex MRLs, increase the number of chemicals in the JMPR/CCPR system for evaluation, and be responsive to both their consumers and their food producers without compromising national health and safety standards and competitive trade advantages.

Food Contamination↗
PubMed1989

[Pesticides and cancer in a Quebec rural farming population: a geographical interpretation].

Data on the use of pesticides in agriculture and three types of cancer among the rural farm population were compiled for 34 drainage basins of the province of Québec for 1982 and 1983. The basins were divided following three categories of exposure (low, intermediate, high) on the basis of the level of pesticides sales. Results at the scale of the three categories show that among women living in rural farm areas, the relative risk (RR) for cancers of the lymphatic tissues is of 1.62 when highly exposed basins were compared to low exposed basins (95% Confidence Interval = 1.16; 2.25), and of 1.63 (95% CI = 1.08; 2.45) when they were compared to basins with intermediate exposure. For women of 35-64 age group, RR values are respectively of 3.15 (95% CI = 1.67; 5.93) in the first case, and 3.73 (95% CI = 1.54; 9.01) in the second case. By another way, at the level of the 34 drainage basins, correlation analysis have shown statistically significant positive associations between several variables representing pesticides utilization in agriculture and geographic variations of some cancers, according to sex and age groups, especially for the following: men, cancer of the brain (1-14 and 15-34 age groups), cancers of the lymphatic tissues (34-64) and leukaemia (1-14); for women, cancer of the brain (35-64), the lymphatic tissues (35-64, 65 and more, all ages) and leukaemia (15-34, 35-64, 65 and more and all ages). After that, principal components analysis has been performed using variables representing pesticides utilization and socio-economic status by basin. Height factors have been produced, including two socio-economic and six pesticides-factors. Factor scores have been introduced in multiple regression analysis to see the role of each factor in the explanation of spatial distribution of those cancers who had been identified in the correlation analysis before. Results have shown that in most of the cases, only pesticides-factors have significant relationship with those cancers. Socio-economic factors play a significant role only for the following cancers: men, lymphatic tissues, 65 years old and more; women, cancer of the brain all ages, leukaemia 1-14 and 65 years old and more. However, these results must be interpreted with caution for the goal of the study is to describe potential relationships.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1986

Progress in pesticide exposure studies and future concerns.

A campaign to educate the public regarding the merits of pesticides is necessary if we are to overcome the widespread poor image of pesticides that exists in society today. A comparison of biological monitoring and measurements of pesticide deposition on patches suggests that since only the absorbed dose has any potential for adverse health effects if forced to choose one technique over the other, more emphasis should be placed on biological monitoring. Controlled human pesticide exposure and dermal absorption studies establishing pharmacokinetic data are necessary if scientists and regulatory officials are expected to make knowledgeable worker safety recommendations pertaining to the pesticides being used today. Worker exposure can continue beyond the application day if pesticide-contaminated boots or gloves are used later. Excretion rate of 2,4-D in human urine was not affected by the presence of picloram in the application mixture. Margins of safety guidelines are highly dependent on adoption of appropriate no observed effect levels (NOEL).

Agriculture↗
PubMed1995

Recent epidemics of poisoning by pesticides.

The mechanisms of production of collective poisoning by pesticides have been contamination of foods consumed by man, cutaneous contact and occupational exposure. It is possible to distinguish 4 groups of alimentary epidemics: (1) contamination during transport or storage; (2) ingestion of seed dressed for sowing: (3) use of pesticides in food preparation because of their organoleptic similarity to alimentary products; (4) presence of pesticides in water or food owing to unsafe use of pesticides. Occupational exposure affects clusters of workers in pesticide manufacture, pesticide application and crop management. Some episodes of every kind of the mentioned groups have been published recently.

Food Contamination↗
PubMed2006

Control selection and pesticide exposure assessment via GIS in prostate cancer studies.

BACKGROUND: Pesticide exposures have recently been linked to prostate cancer, but accurate exposure assessment to date has been challenging. Additionally, historical exposures have rarely been examined. The utility of a geographic information system (GIS)-based model for assessing residential exposure to pesticides is examined in a population-based case-control setting among groups easily recruited as control subjects. METHODS: Historical pesticide and land-use data were used to generate exposure measures for two distinct pesticides previously linked to prostate cancer risk for control series and prostate cancer cases in three rural California counties. Simple estimates of residential exposures for different exposure periods are compared between case and control groups and the value of complete residential histories is examined. RESULTS: Residential exposure to methyl bromide based on current address resulted in an overestimation of exposure for distant exposure periods, whereas exposures to organochlorines were similar regardless of availability of historical residence information. A response bias was detected in Medicare controls such that unexposed elderly control subjects were characterized by a higher response rate. CONCLUSIONS: The frequency and amount of application of pesticides seem to affect the bias introduced into GIS-based exposure assessments. Inclusion of subjects' complete residential histories into the computation of exposure estimates seems to reduce bias from this source, but it may also introduce an additional bias through control self-selection. The use of randomly sampled controls from Medicare and residential parcels listings independent of subject response seems to result in the opportunity for relatively unbiased estimates of pesticide exposures.

Aged↗
PubMed2004

Role of B-esterases in assessing toxicity of organophosphorus (chlorpyrifos, malathion) and carbamate (carbofuran) pesticides to Daphnia magna.

In this study, the cladoceran Daphnia magna was exposed to two model organophosphorous and one carbamate pesticides including malathion, chlorpyrifos and carbofuran to assess acetylcholinesterase (AChE) and carboxylesterase (CbE) inhibition and recovery patterns and relate those responses with individual level effects. Our results revealed differences in enzyme inhibition and recovery patterns among the studied esterase enzymes and pesticides. CbE was more sensitive to organophosphorous than AChE, whereas both CbE and AChE showed equivalent sensitivities to the carbamate carbofuran. Recovery patterns of AChE and CbE activities following exposure to the studied pesticides were similar with 80-100% recoveries taking place 12 and 96 h after exposure to organophosphorous and carbamates pesticides, respectively. The physiological role of AChE and CbE inhibition patterns in Daphnia was examined by using organophosphorous and carbamate compounds alone and with specific inhibitors of CbE. Under exposure to organophosphorous pesticides, survival of Daphnia juveniles was impaired at AChE inhibition levels higher than 50% whereas under exposure to the carbamate carbofuran low levels of AChE inhibition affected mortality. Inhibition of CbE by 80-90% increased toxicity to organophosphorous and carbamate pesticides by up to two- and four-fold, respectively. Our results suggest that both AChE and CbE enzymes are involved in determining toxicity of Daphnia to the studied chemicals and that AChE inhibition levels higher than 50% can be considered of environmental concern to Daphnia species.

Animals↗
PubMed2005

A comparison of predicted and measured levels of runoff-related pesticide concentrations in small lowland streams on a landscape level.

Short-term pollution events via runoff are typical of streams in agricultural areas. Existing runoff models that simulate pesticide loss from agricultural fields require extensive input of information. There is thus a need for a simple model that can predict runoff-related pesticide concentrations in many streams on a landscape level when only limited data are available. To validate such a model, the runoff-related pesticide load of 18 small lowland streams was predicted with an extended version of the model "simplified formula for indirect loadings caused by runoff" (available from the Organisation for Economic Cooperation and Development, OECD). The authors suggest that the model presented here is suitable for use in routine exposure assessment of pesticides on a landscape level, as all input data (soil, slope, precipitation, pesticide application) are readily available from public authorities or could be generated by simple regional flood hydrograph curves. The predicted concentrations were compared with measured concentrations obtained by runoff-triggered sampling. Fungicides, insecticides and herbicides were detected in 17 streams, with max. concentrations measuring up to 29.7 microg/l for the fungicide azoxystrobin and 0.3 microg/l for the insecticide parathion-ethyl. Herbicides were detected in 16 streams, with max. concentrations between 13.7 and 1.2 microg/l. The linear regression between the predicted and measured concentrations (log-values) shows significant correlations for the following pesticides: azoxystrobin: r2=0.43; p=0.03; epoxiconazole: r2=0.71; p or=0.5 microg/l).

Fresh Water↗
PubMed2005

Prediction of pesticide volatilization with PELMO 3.31.

In the current EU risk assessment for pesticide registration, the European Community requires prediction of the concentration of each pesticide in air. A number of mathematical models are used to assess the fate of pesticides in groundwater, surface water and soil. PELMO 3.20 calculates the volatilization fluxes from bare soil and was improved in the new version PELMO 3.31 to include the effect of temperature and sorption in dry soil. The objective of this study was to evaluate the new version of PELMO 3.31 in predicting the pesticide volatilization under field conditions. Procymidone, malathion, and ethoprophos were the test compounds in two different seasons (autumn and winter). Comparing simulation results obtained with PELMO 3.31, after calibration, with the previous version PELMO 3.20 shows that the estimated volatilization results seems improved for malathion, similar or slightly overestimating in the warmer season for ethoprophos, and similar or slightly underestimating in the colder season for procymidone. The new release of PELMO allows a more accurate estimation of pesticides volatilization from soil as function of meteorological factors, especially for medium or low volatility pesticides. Some difficulties remain, such as the determination of the active air layer and the sorption increment with the soil drying.

Air Pollutants↗
PubMed2006

Trace elements in major solid-pesticides used in the Gaza Strip.

This study describes the purity of pesticides used in Gaza in terms of trace elements. A semi-quantitative EMMA-XRF technique and quantitative ICP/OES was used to determine the concentrations of Al, As, Ba, Br, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, Sc, Se, Sr, Ti and Zn in 50 of the most commonly used solid pesticides collected from the five central shops in the Gaza Strip. The results revealed that the pesticides contain considerable amounts of trace elements and do not comply with the expected-theoretical structure of each species. Moreover, they do not reflect the actual constituents mentioned in the trade labels. Interviews with market owners and field surveys confirmed that the pesticides were not pure. In some cases they have been mixed in local markets with minor inorganic species without a scientific basis. They may also have been smuggled into Gaza with differing impurities. The results indicate that pesticides should be considered as a source of certain trace metals (particularly Cu, Mn and Zn) and other elements (Br, Sr and Ti), which may affect their mass balances in soil and groundwater as well as their plant uptake. Different scenarios and calculation models of the transport of trace elements in soil and groundwater of the Gaza Strip should include pesticides as an additional source.

Environmental Monitoring↗
PubMed2004

Monitoring multi-class pesticide residues in fresh fruits and vegetables by liquid chromatography with tandem mass spectrometry.

A new analytical method was developed using liquid chromatography with tandem mass spectrometry for the routine analysis of 31 multi-class pesticide residues and applied to approximately 50 fresh fruit and vegetable samples (green bean, cucumber, pepper, tomato, eggplant, watermelon, melon and zucchini). Extraction of the pesticides with ethyl acetate was carried out. The optimal ionisation conditions were selected for each pesticide in the same run. The procedure was validated and the values of some merit figures, such as recovery, precision, linear range, detection limit and quantification limit for each pesticide were calculated together with its calculated expanded uncertainty (U). The average recoveries in cucumber obtained for each pesticide ranged between 74 and 105% at two different fortification levels (n = 10 each) that ranged between 9 and 250 ng g(-1) (depending on the pesticide). The uncertainty associated to the analytical method was lower than 23% for all compounds tested. The calculated limits of detection and quantitation were typically <1 ng g(-1) that were much lower than the maximum residue levels established by European legislation.

Capsicum↗
PubMed2005

Matching unknown empirical formulas to chemical structure using LC/MS TOF accurate mass and database searching: example of unknown pesticides on tomato skins.

Traditionally, the screening of unknown pesticides in food has been accomplished by GC/MS methods using conventional library searching routines. However, many of the new polar and thermally labile pesticides and their degradates are more readily and easily analyzed by LC/MS methods and no searchable libraries currently exist (with the exception of some user libraries, which are limited). Therefore, there is a need for LC/MS approaches to detect unknown non-target pesticides in food. This report develops an identification scheme using a combination of LC/MS time-of-flight (accurate mass) and LC/MS ion trap MS (MS/MS) with searching of empirical formulas generated through accurate mass and a ChemIndex database or Merck Index database. The approach is different than conventional library searching of fragment ions. The concept here consists of four parts. First is the initial detection of a possible unknown pesticide in actual market-place vegetable extracts (tomato skins) using accurate mass and generating empirical formulas. Second is searching either the Merck Index database on CD (10,000 compounds) or the ChemIndex (77,000 compounds) for possible structures. Third is MS/MS of the unknown pesticide in the tomato-skin extract followed by fragment ion identification using chemical drawing software and comparison with accurate-mass ion fragments. Fourth is the verification with authentic standards, if available. Three examples of unknown, non-target pesticides are shown using a tomato-skin extract from an actual market place sample. Limitations of the approach are discussed including the use of A + 2 isotope signatures, extended databases, lack of authentic standards, and natural product unknowns in food extracts.

Chromatography, Liquid↗
PubMed2005

Macroinvertebrate community structure in agricultural streams: impact of runoff-related pesticide contamination.

This study aims to assess the runoff-related pesticide contamination, among other environmental factors, that contributes to differentiation in the macroinvertebrate communities inhabiting six streams in northern Germany (Braunschweig, Lower Saxony). A total of 91 macroinvertebrate taxa were sampled three times (April, May and June 2000) during the main period of pesticide application to cereals and sugar beets in the catchment. Thirteen environmental variables (e.g., nutrients, discharge, in-stream structure), including runoff-related pesticide concentrations expressed as a sum parameter based on toxicity units (TU(SUM)), were analyzed using canonical correspondence analysis (CCA) and redundancy analysis. CCA based on species-level data and environmental variables explained 48% of the variance, with TU(SUM), stream width, percentage of detritus in the stream bed, and temperature being the most important variables. The sampling dates were of minor importance for the classification. The community composition in three streams exposed to maximum total pesticide levels between 0.2 x and 0.01 x acute toxicity to Daphnia (48-h LC(50)) was clearly distinct from that at three control sites. Redundancy analysis using average values of the environmental variables and taxonomic orders explained 95% of the variance, with TU(SUM) being the only significant variable. The results show that the present pesticide levels affect the invertebrate community structure in the field. Furthermore, they underline the potential for effects in the field at pesticide concentrations greater than 0.01 x acute toxicity to Daphnia and are thus in agreement with the assumptions underlying the standards set by the European Union uniform principle.

Agriculture↗
PubMed2005

Scenario-based simulation of runoff-related pesticide entries into small streams on a landscape level.

The prediction of runoff-related pesticide entry into surface waters on a landscape level usually requires considerable efforts with regard to input data, time, and personnel. Therefore, the need for an easy to use simulation tool with easily accessible input data, for example from already existing public sources, is obvious. In this paper, we present a simulation tool for the simulation of pesticide entry from arable land into adjacent streams. Our aim was to develop a tool applicable on the landscape level using "real world data" from numerous sites and for the simulation of parameter case studies concerning particular parameters at single sites. We used the ratio of exposure to toxicity (REXTOX) model proposed by the OECD, which had been successfully validated in the study area as part of a previous study and which was extended to calculate pesticide concentrations in adjacent streams. We simulated the pesticide entry on the landscape level at 737 sites in small streams situated in the central lowland of Germany with winter wheat, barley, and sugar beat as the main agricultural crops. A sensitivity analysis indicated that the most significant model parameters were the width of the no-application zone and the degree of plant interception. The simulation was carried out for the 15 most frequently detected substances found in the study area using eight different environmental scenarios, covering variation of the width of the no-application zone, climate, and seasonal scenarios. The highest in-stream concentrations were predicted for a scenario using no (0m) buffer zone in conjunction with increased precipitation. According to the predicted concentrations, the risk for the aquatic communities was estimated based on standard toxicity tests and the application of a safety factor. The simulation results are presented both by means of risk maps for the study area showing the simulated pesticide concentration and the resulting ecological risk for numerous sites under varying scenarios and by case study diagrams with focus on the model behavior under the influence of single parameters. Risk maps confirmed the importance of no-application (buffer) zones for the levels of pesticide input. They also indicated the importance of the existing no-application zones for certain compounds and in some cases the need for a further evaluation of these regulations. The simulation tool was implemented as a standard PC software combining the REXTOX model with a geographical information system and can be used on any current personal computer. All input data was taken from public sources of German authorities. With little effort the tool should be applicable for other areas with similar data quality.

Computer Simulation↗
PubMed2005

How to accurately assay the algal toxicity of pesticides with low water solubility.

A novel method for assaying and calculating the toxicity of water-insoluble pesticides to green algae has been put forward in this work. First, a solvent is selected for use in bioassays; there should be a detailed screening to identify a solvent with inherently low toxicity to the test organism. Second, the EC50 is determined for selected pesticides by measuring the toxicity of various concentrations of each of the selected pesticides in a fixed concentration of selected solvent. Third, concentrations of the selected solvent are varied and the EC50 of each pesticide tested is assayed at a fixed concentration. Fourth, several suitable groups of solvent concentrations are selected and the corresponding EC50 values of tested pesticides are considered to establish the linear regression equation. Letting the solvent concentration be zero, one calculates the corresponding EC50 value, which corresponds to the inherent toxicity of the tested pesticide.

Biological Assay↗
PubMed2006

Measurement of human urinary organophosphate pesticide metabolites by automated solid-phase extraction derivation and gas chromatography-tandem mass spectromy.

Organophosphorus (OP) pesticides are among the most widely used pesticides in the United States. Human exposure to these pesticides may occur from their use on crops in agriculture and for pest control in residential settings. Most of the OP pesticides used in the United States are metabolized to up to three of six common urinary dialkyl phosphate metabolites. Quantification of these metabolites provides information on cumulative exposure to most OP pesticides. To accurately quantify OP pesticide metabolites in human urine, we developed a simple, highly sensitive, analytic method involving automated solid-phase extraction (SPE) of human urine, followed by post-extraction derivatization of the organophosphorus metabolites with 1-chloro-3-iodopropane, and analysis by isotope dilution gas-chromatography-tandem mass spectrometry. The styrene-divinyl benzene polymer-based SPE cartridges yielded good SPE recoveries of the metabolites because of their enhanced non-polar interactions. This method is less labor-intensive, more time-efficient, and reproducible than previously reported methods. Automation of the SPE allowed unattended extraction of urine samples, and hence, increased the sample throughput and reduced the inter- and intra-day variations. The method limits of detection were excellent for all analytes ranging from 50 pg/ml to 170 pg/ml. Relative standard deviations ranged from 2% to 12%.

Automation↗
PubMed2004

Breast cancer incidence and its possible spatial association with pesticide application in two counties of England.

BACKGROUND: This study examines the spatial distribution of breast cancer incidence in Lincolnshire and Leicestershire, and its association with the application of selected pesticides. METHODS: The Black-White (BW) join-count statistic and Moran I coefficient were used to investigate the localized distribution of breast cancer. Linear regression techniques were applied to examine the association between the breast cancer incidence rate and pesticide application. RESULTS: The results from the BW join-count test and the Moran I coefficient test showed no overall evidence of localized distribution, 'clusters', of breast cancer. The regression analyses showed no sign of spatial association between breast cancer and application of pesticides in the urban areas as expected. The findings, however, did reveal a spatial association between the breast cancer incidence rates and the application of three selected pesticides [Aldicarb, Atrazine and Lindane (thought to potentially mimic oestrogen)] in rural Leicestershire. No such association was seen in Lincolnshire. CONCLUSIONS: Pesticides vary significantly in their spatial application. Overall, consistent associations between breast cancer incidence rates and the selected pesticides were not found, although the ecological study design has limitations and these are discussed. This approach is able to rule out strong associations; assessment of smaller risk would require a large and expensive study in individuals. The results of this study, although derived in the UK, have significance to the debate concerning the possibility of environmental compounds that mimic oestrogen and their consequences for human health.

Aged↗
PubMed2004

Twenty-four-hour urinary excretion of ten pesticide metabolites in healthy adults in two different areas of Italy (Florence and Ragusa).

The determination of pesticide metabolites in human biological fluids represents an important biomarker of exposure in the general population and exposed workers. In the frame of a prospective study, we measured the 24-h urinary excretion of 10 pesticide metabolites to evaluate non-occupational exposure to pesticides in the general population in two different areas in Italy. We collected 24-h urine samples from 69 healthy adults residing in Florence (Central Italy, n = 51) and Ragusa (Southern Italy, n = 18). The volunteers (25 males, 44 females; mean age 56 years) did not report any occupational exposure. We measured: six alkylphosphates, aspecific metabolites of organophosphorus pesticides [dimethylphosfate (DMP), dimethylthiophosfate (DMTP), dimethyldithiophosfate (DMDTP), diethylphosfate (DEP), diethylthiophosfate (DEDP), and diethyldithiophosfate (DEDTP)]; 3,5,6-trichloro-2-pyridinol (TCP), the main metabolite of chlorpyrifos; 3-phenoxybenzoic acid (3-PBA), a metabolite of pyrethroid insecticides; ethylenethiourea (ETU) a metabolite of ethylenebisdithiocarbamates; methamidophos (METH), an organophosphorus insecticide. We also measured PABA excretion as compliance marker (mean recovery 95%). Dimethylphosphates were found in detectable concentrations in the majority of samples (89.9%, 82.6% and 60.9% for DMP, DMTP and DMDTP, respectively). Urinary diethylphosphates (DEP, DETP, DEDTP) concentrations were above the detection limit in 80.9%, 61.8% and 27.5% of samples, respectively. TCP, 3-PBA and ETU were detected in 78.3%, 53.6% and 21.7% of samples, respectively. Methamidophos was detected in two samples (2.8%). The median number of metabolites detected in the same urine sample was 6 (range 0-9). Excretion levels were highest for alkylphosphates, particularly for DMTP (median: 142.6 nmol/day). Multivariate analysis showed statistically significant differences between these two groups of adults, with higher mean values of urinary excretion of alkylphosphates, TCP and ETU in Florence in comparison to Ragusa. Overall, a very high percentage of 24-h urine samples positive for several pesticide metabolites emerged, with higher levels of urinary daily excretion in subjects residing in the more urbanised area. Our results suggest that food monitoring programs should be supported by general campaigns aimed to reduce the use of pesticides in agriculture.

Adult↗
PubMed2005

Comparing pharmaceutical and pesticide loads into a small Mediterranean river.

During 2003/2004, water samples were collected upstream and downstream of two wastewater treatment plant (WWTP) outlets in order to determine the contribution of urban centres to concentration of selected pharmaceuticals (antiphlogistics, lipid regulators and carbamazepine) and pesticides into a Mediterranean river basin (Arc river, Aix en Provence, France). Pharmaceutical loads were compared to pesticide ones. They could be nearly regarded as important as pesticide ones at least at one sampling site. The observed pollution patterns differed from pesticides to pharmaceuticals. Pesticide pollution occurred through a high pollution peak in spring while pharmaceuticals were continuously infused into the river via WWTP effluents. Carbamazepine and bezafibrate were detected in almost all samples at concentration levels ranging from ng/L to microg/L. The major pharmaceutical source could be ascribed to WWTP effluents and pharmaceutical concentrations increased during low flow rate conditions (summer), when municipal wastewater effluents accounted for the majority of the river water flow. Treated wastewaters contributed to a lesser extent to pesticide river water pollution. In an urbanized Mediterranean river basin, a deep understanding of water pollution by organic waste contaminants is required in order to set up an efficient programme of pollution reduction measures.

Agriculture↗