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PubMedDate not supplied

[Pesticides in the diet: adding pieces to the puzzle].

OBJECTIVES: To improve information on exposure to pesticides through diet in Spain by reporting the results on 88 pesticide parameters in 1,109 food samples obtained between 1998 and 2003 as part of the Barcelona program for research on the health quality of foods. MATERIAL AND METHOD: The results are presented by food groups. For fruits and vegetables, the results were compared with those for the previous period. Statistical comparisons were performed using the chi2 test. RESULTS: Of the 1,109 samples, 116 were positive for pesticides (10.5%). Persistent chlorinated compounds were detected in 1.5% and other compounds were found in 14.4%. Positive results were concentrated in fruits, vegetables, spices, cereals and their derivatives. There were no positive results among vegetable oils, eggs or fish products, and almost none in dairy products and meats. Fruits contained the greatest number of pesticides but none were persistent. Vegetables contained fewer pesticides, but some of these were persistent chlorinated compounds. Comparison of the results for fruits and vegetables with those of the 1989-97 period revealed no significant trends. CONCLUSIONS: Although a considerable number of samples contained pesticides, most of these were not persistent chlorinated compounds. The number of pesticides in fruits was notable.

Food Contamination↗
PubMed2003

Estrogenic and esterase-inhibiting potency in rainwater in relation to pesticide concentrations, sampling season and location.

In a year-round monitoring program (1998), pesticide composition and toxic potency of the mix of pollutants present in rainwater were measured. The goal of the study was to relate atmospheric deposition of toxic potency and pesticide composition to each other and to sampling period and local agricultural activity. Rainwater was collected in 26 consecutive periods of 14 days in a background location (BACK) and in two locations representative for different agricultural practices, i.e. intensive greenhouse horticulture (HORT) and flower bulb culture (BULB). Samples were chemically analyzed for carbamate (CARB), organophosphate (OP) and organochlorine (OC) pesticides and metabolites. Esterase inhibiting potency of rainwater extracts was measured in a specially developed bio-assay with honeybee esterases and was expressed as an equivalent concentration of the model inhibitor dichlorvos. Estrogenic potency of the extracts was measured in the ER-CALUX reporter gene assay and was expressed as an equivalent concentration of estradiol. Multivariate principal component analysis (PCA) techniques proved to be valuable tools to analyze the numerous pesticide concentrations in relation to toxic potency, sampling location, and sampling season. Pesticide composition in rainwater depended much more on sampling season than on sampling location, but differences between and were mainly attributed to local differences in agricultural practice. On average, the esterase inhibiting potency exceeded the maximum permissible concentration set for dichlorvos in The Netherlands, and was significantly higher in than in and . Esterase inhibition correlated significantly with OP and CARB concentrations, as expected given the working mechanism of these insecticides. The estrogenic potency incidentally exceeded NOEC levels reported for aquatic organisms and was highest in . Although estrogenic potency of rainwater correlated with OC concentrations, the ER-CALUX responses could not be attributed to any particular pesticides. Besides, the contribution of non-analyzed xeno-estrogens as alkylphenol(-ethoxylates) and bisphenol-A to the estrogenic potency of rainwater could not be excluded. Further research should focus on the chemical identification of estrogenic compounds in rainwater. In addition, more attention should be given to the ecological consequences of atmospheric deposition of individual pesticides and of total toxic potencies that regularly exceed environmental criteria for Dutch surface waters and/or toxic threshold values for aquatic organisms.

Agriculture↗
PubMed2000

Biological Monitoring of Pesticide Exposure: a review. Introduction.

Pesticides are used worldwide in agriculture, industry, public health and for domestic applications: as a consequence, a great part of the population may be exposed to these compounds. In spite of this extensive use, knowledge on the health risks associated with prolonged exposure is rather poor, and major uncertainties still exist. Epidemiological observations in man have so far produced little conclusive information, mainly because of weaknesses in exposure assessment. Therefore, information on the type and levels of exposure is fundamental in order to better understand and characterize risk to human health. Exposure assessment can be carried out via measurement of environmental concentrations, as well as via determination of the chemical or its metabolites in body tissues (biological monitoring). Besides indices of internal dose, biological monitoring also includes measurements of early effects attributable to interaction between the chemical agent and the human body. Biological monitoring has the advantage, over environmental monitoring, of determining the dose actually absorbed via any possible route: differences in absorption can be taken into account. whether they are due to biological variability or to use of protective equipment. When, in some cases, a combination of occupational and non-occupational exposure occurs, this also can be taken into consideration by biological monitoring. Few reference documents have been published on biological monitoring of pesticides. For this reason, the Office of Occupational Health of the World Health Organization gave ICPS a mandate to prepare a monograph specifically addressed to reviewing methods for biological monitoring of pesticide exposure. This review is based on more than 300 studies published over the period 1980-1999. For the most representative chemical classes, the available biological exposure indices are reported. Both indices of internal dose and. when available, of early effects are discussed. The reported tests were used to monitor exposure of pesticide applicators in agriculture and public health, manufacturing and formulating workers. subjects poisoned after accidental exposure or attempted suicide, volunteers involved in pharmacokinetic studies, as well as sub-groups of the general population exposed to environmentally persistent pesticides. Single chapters deal with organophosphorus insecticides, carbamate pesticides, dithiocarbamates, phenoxyacids, quaternary ammonium compounds. coumarin rodenticides, synthetic pyrethroids, organochlorine pesticides, chlorotriazines, and pentachlorophenol.

Animals↗
PubMed1997

Pesticide residues in food: investigation of disparities in cancer risk estimates.

Much of the public perceives that exposure to synthetic pesticide residues in the diet is a major cause of cancer. The National Research Council (NRC), in a 1987 report, Regulating Pesticides in Food: The Delaney Paradox, evaluated cancer risks for 29 pesticides that are rodent carcinogens and estimated that the risks for 23 were greater than one-in-a-million. In contrast, our group has ranked possible carcinogenic hazards from a variety of human exposures to rodent carcinogens using the HERP (Human Exposure/Rodent Potency) index, and found that dietary residues of synthetic pesticides ranked low. This paper evaluates the disparities in these analyses by examining the two components of risk assessment: carcinogenic potency in rodents and human exposure. Potency estimates based on rodent bioassay data are shown to be similar whether calculated, as in the NRC report, as the regulatory q1* or as TD50. In contrast, estimates of dietary exposure to residues of synthetic pesticides vary enormously, depending on whether they are based on the Theoretical Maximum Residue Contribution (TMRC) calculated by the Environmental Protection Agency vs. the average dietary residues measured by the Food and Drug Administration in the Total Diet Study (TDS). The TMRC is the theoretical maximum human exposure anticipated under the most severe field application conditions, which are far greater than dietary residues measured in the TDS. Several independent exposure studies suggest that the FDA dietary residues are reasonable estimates of average human exposures, whereas TMRC values are large overestimates. Using standard methodology and measured dietary residues in the TDS, the estimate of excess cancer risk from average lifetime exposure to synthetic pesticide residues in the diet appears to be less than one-in-a-million for each of the ten pesticides for which adequate data were available.

Animals↗
PubMed2001

Toxicological assessment of biological pesticides.

The majority of pesticides are based on synthetic chemicals. Regulatory assessments are performed by comparing the findings in a range of routine toxicity studies, designed for testing chemicals, with estimates of exposures. Recently there have been significant moves towards developing natural/biological alternatives. Biological pesticides (those based on viable organisms) present the regulator with a different set of challenges to those raised by most chemical pesticides. The concerns associated with biological pesticides can vary greatly from one organism to another, requiring an almost case-by-case approach. The known toxicity of certain bio-molecules and the pathogenicity of certain organisms underlines the need for a risk assessment of biological pesticides. The main aspects of a health risk assessment are characterisation of the organism, infectivity, pathogenicity, sensitisation and production of toxic secondary metabolites. Obtaining information or data on these areas is not always easy as there are no widely accepted test schemes or protocols for organisms, though guidelines are being developed for the European Commission (EC). Predicting exposure following pesticidal use of an organism is made more complex if it multiplies or secretes toxic metabolites. Reliable data on effects (lack of) associated with naturally occurring (background) exposures can sometimes provide considerable reassurance. This paper describes the background to the proposed EC scheme, which has much in common with current UK practices, and presents three examples of biological pesticides which have been assessed under the existing UK procedures.

Animals↗
PubMed1999

The influence of various factors on immune toxicity assessment of pesticide chemicals.

Various physiological and environmental factors are known to modulate pesticide-induced immune toxicity. Some of these factors studied in our laboratory are: (a) level of exposure (amount, duration and frequency), (b) human cases/animal models, (c) antigen, its route and adjuvant used, (d) immunological method used, (e) nutritional status and pathological conditions, (f) biotransformation and activity of metabolites, (g) physical/emotional stress, and (h) oxidative stress. These factors complicate the assessment of immune toxicity of pesticide, generally affecting the dose at which toxic effects are observed. Working with organochlorine, organophosphate and carbamate compound, we have found that: (1) dietary protein deficiency makes the immune system more susceptible to the toxic effects of pesticides; (2) suppression of immune responses by the immediate metabolites is an important determinant of the toxicity of parent compound; (3) the type and duration of physical or emotional stress and possible involvement of free radicals (oxidative stress) are important in the potentiation of pesticide-induced immune toxicity. An understanding of these risk factors depends largely upon the cellular and molecular events underlying pesticide-induced immune alterations in experimental animals. These factors, therefore, must be considered in the safety/toxicity evaluation of any pesticide. This paper reviews the influence of these factors on the immune-toxicity of some common pesticides.

Animals↗
PubMed2001

The impact of two pesticides on olfactory-mediated endocrine function in mature male Atlantic salmon (Salmo salar L.) parr.

Short-term exposure of the olfactory epithelium of mature male Atlantic salmon parr to either the pesticide simazine (concentrations 1.0 and 2.0 microg l(-1)) or the pesticide atrazine (concentration 1.0 microg l(-1)) significantly reduced the olfactory response to the female priming pheromone, prostaglandin F(2alpha). In addition, the reproductive priming effect of the pheromone on the levels of expressible milt was also reduced after exposure to the individual pesticides (simazine 0.1, 0.5, 1.0 and 2.0 microg l(-1) and atrazine 0.5 and 2.0 microg l(-1)). When the olfactory epithelium was exposed to a mixture of simazine and atrazine, (concentrations of 0.5:0.5 and 1.0:1.0 microg l(-1)), there was no significant reduction in the olfactory response when compared to the single pesticides at equivalent concentrations. In addition, exposure to a mixture of simazine and atrazine had no synergistic effect on the priming response, and plasma levels of testosterone, 11-ketotestosterone and 17,20beta-dihydroxy-4-pregnen-3-one were similar in the groups of male parr exposed to the individual pesticides. Although the levels of expressible milt were reduced in all groups, there were no significant differences between the different pesticide treatments. The results of the study suggest that the two s-triazine pesticides have an additive and not a synergistic impact on olfactory-mediated endocrine function in mature male salmon parr.

Animals↗
PubMed2007

Identification of pesticide transformation products in food by liquid chromatography/time-of-flight mass spectrometry via "fragmentation-degradation" relationships.

The identification of transformation products of pesticides in foodstuffs is a crucial task difficult to tackle, due to the lack of standards and scarce information available. In this work, we describe a methodology for the identification and structural elucidation of pesticide transformation products in food. The proposed strategy is based on the use of liquid chromatography electrospray time-of-flight mass spectrometry (LC/TOFMS): accurate mass measurements of (molecule and fragment) ions of interest are used in order to establish relationships between fragmentation of the parent pesticides in the instrument (in-source CID fragmentation) and possible degradation products of these pesticides in food. Examples of this strategy showing the potential of LC/TOFMS to determine unknown pesticides in food are described in two different real samples, suggesting that pesticides often are transformed into degradation products in the same fashion that they are fragmented in the instrument. Using the proposed approach and without using standards a priori, based solely on accurate mass measurements of ions and "fragmentation-degradation" relationships, we have identified two parent pesticides (amitraz and malathion) along with six degradation products, m/z 253 (N,N'-bisdimethylphenylformamidine), 163 (N-2,4-dimethylphenyl-N-methyl formamidine), 150 (2,4-dimethylformamidine), and 122 (2,4-dimethylaniline) from amitraz, and m/z 317 and 303, due to ether hydrolysis of methyl and ethyl groups from malathion. Structures for these species were proposed, and the potential of the proposed approach was critically discussed.

Amidines↗
PubMed2004

Alteration of mammalian-cell toxicity of pesticides by structural iron(II) in ferruginous smectite.

The ultimate concern over pesticides in the environment is their toxic impact on nontarget organisms, including humans. Soil clays are known to interact with pesticides in ways that decrease the concentration of the parent compound in the soil solution (adsorption, sequestration, degradation). These phenomena are generally regarded as beneficial, but toxicological verification is lacking. In this study, mammalian-cell cytotoxicity of four commonly used agricultural chemicals (2,4-D, alachlor, dicamba, and oxamyl) was assessed after exposure to either reduced or oxidized ferruginous smectite (SWa-1). Results revealed that treatment with reduced smectite produced differential effects on mammalian-cell viability, depending on the pesticide. Oxamyl and alachlor reacted with reduced SWa-1 showed a significant decrease in their overall cytotoxic potential. Dicamba reacted with the reduced-clay treatment and generated products that were more toxic than the parent pesticide. Finally, no differences were observed between redox treatments for 2,4-D. The significance of these results is that oxidized smectites have virtually no influence on the toxicity of pesticides, whereas reduced-Fe smectite plays an important role in altering the cytotoxic potential of agricultural pesticides. The Fe oxidation state of clay minerals should, therefore, be taken into account in pesticide management programs.

Agriculture↗
PubMed2005

Measuring and predicting environmental concentrations of pesticides in air after application to paddy water systems.

In this study, the volatilization of five pesticides applied to an artificial flooded paddy field was assessed using the theoretical profile shape (TPS) and the integrate horizontal flux (IHF) techniques. The dataset derived was utilized to improve the volatilization routine of the rice water quality (RICEWQ) model. The masses of pesticides ethoprophos, procymidone, metalaxyl, chlorpyrifos, and chlorpyrifos methyl volatilized from paddy water and their concentrations in paddy water were determined for a period of 6 d after application. The highest and lowest volatilization losses were observed for chlorpyrifos and metalaxyl, respectively, accounting for 3.3% and 0.03% of their initially applied amount. A rapid pesticide dissipation was evident in paddy water during the study period. The RICEWQ model was used to simulate the fate of pesticides in the artificial paddy system. The Kvolat, an empiric coefficient used by the model as an input parameter, was calculated for all pesticides through model calibration. RICEWQ simulated well the fate of pesticides in paddy water. A significant regression correlation between Henry's law constant (Hk) and Kvolat of the studied compounds was established which could facilitate the parametrization of the model for describing pesticide volatilization.

Agriculture↗
PubMed2006

Pesticide measurements from the first national environmental health survey of child care centers using a multi-residue GC/MS analysis method.

The U.S. Department of Housing and Urban Development, in collaboration with the U.S. Consumer Product Safety Commission and the U.S. Environmental Protection Agency, characterized the environments of young children (<6 years) by measuring lead, allergens, and pesticides in a randomly selected nationally representative sample of licensed institutional child care centers. Multi-stage sampling with clustering was used to select 168 child care centers in 30 primary sampling units in the United States. Centers were recruited into the study by telephone interviewers. Samples for pesticides, lead, and allergens were collected at multiple locations in each center by field technicians. Field sampling was conducted from July through October 2001. Wipe samples from indoor surfaces (floors, tabletops, desks) and soil samples were collected at the centers and analyzed using a multi-residue GC/MS analysis method. Based on the questionnaire responses, pyrethroids were the most commonly used pesticides among centers applying pesticides. Among the 63% of centers reporting pesticide applications, the number of pesticides used in each center ranged from 1 to 10 and the frequency of use ranged from 1 to 107 times annually. Numerous organophosphate and pyrethroid pesticides were detected in the indoor floor wipe samples. Chlorpyrifos (0.004-28 ng/cm2), diazinon (0.002-18 ng/cm2), cis-permethrin (0.004-3 ng/cm2), and

Child Day Care Centers↗
PubMed2000

Reduction of pesticide residues on produce by rinsing.

In 1997 this laboratory initiated a research program with the objective of examining the effect that rinsing of produce with tap water would have on pesticide residues. Samples were obtained from local markets and/or grown at our experimental farm. Because approximately 35% of produce from retail sources contains pesticide residues, growing and treating produce at an experimental farm had the advantage that all such samples contain pesticide residues. Pesticides were applied under normal field conditions to a variety of food crops and the vegetation was allowed to undergo natural weathering prior to harvest. The resulting samples contained field-incurred or "field-fortified" residues. This experimental design was employed to mimic as closely as possible real world samples. Crops were treated, harvested, and divided into equal subsamples. One subsample was processed unwashed, whereas the other was rinsed under tap water. The extraction and analysis method used was a multi-residue method developed in our laboratory. Twelve pesticides were included in this study: the fungicides captan, chlorothalonil, iprodione, and vinclozolin; and the insecticides endosulfan, permethrin, methoxychlor, malathion, diazinon, chlorpyrifos, bifenthrin, and DDE (a soil metabolite of DDT). Statistical analysis of the data using the Wilcoxon signed-rank test showed that rinsing removed residues for nine of the twelve pesticides studied. Residues of vinclozolin, bifenthrin, and chlorpyrifos were not reduced. The rinsability of a pesticide is not correlated with its water solubility.

Chromatography, Gas↗
PubMed2001

Leaching of pesticides in tea brew.

A cup of tea that cheers can also be an important route of human exposure to pesticide residues. It is important to evaluate the percent transfer of pesticide residue from dried (made) tea to tea infusion, as tea is subjected to an infusion process prior to human consumption. To investigate the pesticide translocation, 13 pesticides commonly used on tea were studied by subjection of fortified teas to infusion. Analytes of interest were quantified by gas-liquid chromatography with nitrogen-phosphorus and electron capture detectors. Interestingly, water solubility of pesticides did not necessarily indicate a shift of residues toward their preferential accumulation in infusion. The pesticides with larger partition coefficient (K(ow)) values remained nonextractable in infusing water. Further, boiling for longer periods (extended brewing time) resulted in higher transfer of pesticides to tea brew.

Chromatography, Gas↗
PubMed2004

Effect of different soil textures on leaching potential and degradation of pesticides in biobeds.

Biobeds can be used to intercept pesticide-contaminated runoff from the mixing/washdown area, creating optimum conditions for sorption and biodegradation such that the amount of pesticide reaching adjacent water bodies is significantly reduced. The biobed is built on the farm using locally available materials, which include, straw, compost, and topsoil. The topsoil acts as the inoculum for the system and is likely to vary in terms of its physical, chemical, and microbiological characteristics from one farm to another. This study therefore investigated the effects of using different soil types on the degradation and leaching potential from biobeds. Three contrasting topsoils were investigated. Leaching studies were performed using isoproturon, dimethoate, and mecoprop-P, which were applied at simulated disposal rates to 1.5 m deep biobeds. Annual average concentrations were similar for each soil type with leaching losses of even the most mobile (Koc = 12-25) pesticide <1.64% of the applied dose. Greater than 98% of the retained pesticides were degraded in all matrices. Degradation studies investigated the persistence of individual pesticides and pesticide mixtures in the different matrices. DT50 values for isoproturon, chlorothalonil, mecoprop-P, and metsulfuron-methyl applied at 4 times the maximum approved rate were similar across the biomix types and were all less than or equal to reported DT50 values for soil treated at approved rates. When applied as a mixture, DT50 values in each biomix increased, indicating that interactions between pesticides are possible. However, DT90 values of <167 days were obtained in all circumstances, indicating a negligible risk of accumulation. Studies therefore indicate that substrate will have little impact on biobed performance so it should be possible to use local soils in the construction process.

2-Methyl-4-chlorophenoxyacetic Acid↗
PubMed2006

Dynamics of pesticides in potato crops.

This study investigated the behavior of pesticides commonly used on potato in a part of northwestern Spain with a large area devoted to this crop. Experimental potato plots were treated with commercial formulations of two insecticides, a nematicide, a herbicide, and a combination of two fungicides, and the concentrations of the active ingredients were monitored throughout the growing season in the 0-1 and 1-15 cm soil layers, in water dripping off the potato plants, and in the potatoes themselves. The technique used for pesticide determination was gas chromatography with mass selective detection. For potato analyses, pesticide extraction was optimized. The only pesticide ever detected in potato tubers was metalaxyl, the concentration of which never exceeded half the maximum residual limit even when it was applied several times more often than is officially recommended for potato crops. Metalaxyl was also the only pesticide detected in wash-off, apparently due to its being more soluble in water than the other pesticides applied to the growing plants. A mathematical model of pesticide transport in soil was fitted to the experimental data using the program HYDRUS-1D.

Fungicides, Industrial↗
PubMed1997

Determination of genotoxicity of the metabolites of the pesticides Guthion, Sencor, Lorox, Reglone, Daconil and Admire by 32P-postlabeling.

Commercial formulations of the pesticides: Guthion (azinphos methyl), Sencor (metribuzin), Lorox (linuron), Reglone (diquat), Daconil (chlorothalonil) and Admire (imidacloprid) were studied for their genotoxicity by 32P-postlabeling. Metabolites of the pesticides were obtained enzymatically using arochlor induced rat liver S9 fraction, in an NADPH generating system. The resulting metabolites were reacted with calf thymus DNA and the DNA was analyzed for presence of adducts by either the nuclease P1 or butanol enrichment. Nuclease P1 enrichment resulted in adducts for all the pesticides. Compared to the level of adducts in control DNA, the levels in pesticide-treated DNA were higher for all the pesticides, except Daconil. The increase in adduct numbers for pesticide-treated DNAs ranged from 4.9-12.4 times the control-DNA indicating pesticide genotoxicity in this in vitro system. Enrichment using butanol extraction gave three adducts unique to Sencor-DNA. These adducts were different from those obtained with nuclease P1 enrichment of the same. B(alpha)P was the positive control for the in vitro metabolism, and two adduct enrichment procedures: nuclease P1 digestion and butanol extraction.

Adenosine Triphosphate↗
PubMedDate not supplied

Pesticide storage and use patterns in Minnesota households with children.

As part of the National Human Exposure Assessment Survey (NHEXAS), residential pesticide storage and use patterns were evaluated in a population-based sample of Minnesota households with children aged 3-13. In-home interviews and inventories were conducted to identify pesticide products stored and used in and around 308 households. This statistically based sample represents more than 49,000 urban and rural households in the census tracts sampled. More than 850 unique products were identified using Environmental Protection Agency (EPA) registration numbers. Pesticide products were found in 97% and reported used in 88% of study households. Population-weighted mean values for pesticide storage and use were 6.0 and 3.1 products per household, respectively. The most common active ingredients found were diethyl toluamide (DEET) and related compounds, piperonyl butoxide, pyrethrins, dimethylamine 2-[2-methyl-4-chlorophenoxyl propionate (MCPA) and chlorpyrifos. Household socio-demographic characteristics explained little of the variability in pesticide storage and use patterns, and there were no significant differences in residential storage and use patterns between households located in urban versus non-urban census tracts. Although the prevalence of households with pesticide products was similar to recent national surveys, observed storage and use rates were almost twice those obtained in recent national studies, reflecting improved inventory techniques used by this study and/or increased rates of pesticide presence and use in study households.

Adolescent↗
PubMed2002

Questionnaire assessment of nonoccupational pesticide exposure in epidemiologic studies of cancer.

Pesticides have been examined in epidemiologic studies as environmental risk factors for cancer, in part, due to the identification of carcinogenic properties of some of these chemicals using animal models. Although the majority of these epidemiologic studies have focused on occupational pesticide exposure, nonoccupational pesticide exposure has also been investigated. The objective of this paper is to review the methodological issues of nonoccupational pesticide exposure assessment, including identifying the methods that have been used to assess self-reported nonoccupational pesticide exposure in epidemiologic studies of cancer, and discussing the strengths and limitations of the current methodology as well as possible enhancements that could be incorporated into future investigations. Issues of exposure assessment that will be reviewed include specificity, recall, and characteristics of pesticide exposure. Additionally, sources of nonoccupational pesticide exposure other than residential will be briefly reviewed.

Environmental Exposure↗