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Pesticide residue on/in the washed skin and its potential contribution to dermal toxicity.

Washing the skin of humans or experimental animals after exposure to a pesticide or other chemical may leave a major portion of the dose on/in the washed skin. Questions have been raised as to whether this skin residue can contribute to the toxicity of a pesticide by continued post-wash absorption. In a set of 19 pesticides tested in the rat to determine the fate of this skin residue, absorption from the washed skin continued in 15 at all doses tested, continued in 2 pesticides at only some of the doses tested and did not continue in 2 volatile pesticides. However, only nine pesticides showed an increase in systemic concentration following absorption from the washed skin, which can be considered indicative of potential increased toxicity. The time of occurrence and magnitude of the increase varied with chemical and dose, being a combination of rate and magnitude of absorption and rate and magnitude of excretion of the absorbed chemical. Similar patterns of continued absorption of skin residue may be expected to occur in humans.

Animals↗

Optimization of a multi-residue screening method for the determination of 85 pesticides in selected food matrices by stir bar sorptive extraction and thermal desorption GC-MS.

A multi-residue method to determine 85 pesticides, including organochlorine pesticides, carbamates, organophosphorus pesticides, and pyrethroids, in vegetables, fruit, and green tea, has been developed. The method is based on stir bar sorptive extraction (SBSE) coupled to thermal desorption (TD) and retention time locked (RTL) GC-MS operating in the scan mode. Samples are extracted with methanol and diluted with water prior to SBSE. Dilution of the methanol extract before SBSE was optimized to obtain high sensitivity and to minimize adsorption onto the glass wall of the extraction vessel as well as to minimize sample matrix effects (particularly for the pesticides with high log K(o,w) values). The optimized method consists of a dual SBSE extraction performed simultaneously on respectively a twofold and a fivefold diluted methanol extract. After extraction, the two stir bars are placed in a single glass thermal desorption liner and are simultaneously desorbed. The method showed good linearity (r2 > 0.9900) and high sensitivity (limit of detection: < 5 microg kg(-1)) for most of the target pesticides. The method was applied to the determination of pesticides at low microg kg(-1) in tomato, cucumber, green soybeans, spinach, grapes, and green tea.

Food Analysis↗

Residue analysis of 500 high priority pesticides: better by GC-MS or LC-MS/MS?

This overview evaluates the capabilities of mass spectrometry (MS) in combination with gas chromatography (GC) and liquid chromatography (LC) for the determination of a multitude of pesticides. The selection of pesticides for this assessment is based on the status of production, the existence of regulations on maximum residue levels in food, and the frequency of residue detection. GC-MS with electron impact (EI) ionization and the combination of LC with tandem mass spectrometers (LC-MS/MS) using electrospray ionization (ESI) are identified as techniques most often applied in multi-residue methods for pesticides at present. Therefore, applicability and sensitivity obtained with GC-EI-MS and LC-ESI-MS/MS is individually compared for each of the selected pesticides. Only for one substance class only, the organochlorine pesticides, GC-MS achieves better performance. For all other classes of pesticides, the assessment shows a wider scope and better sensitivity if detection is based on LC-MS.

Chromatography, Liquid↗

Time of flight mass spectrometry applied to the liquid chromatographic analysis of pesticides in water and food.

Liquid chromatography coupled to mass spectrometry (LC-MS) is an excellent technique to determine trace levels of polar and thermolabile pesticides and their degradation products in complex matrices. LC-MS can be equipped with several mass analyzers, each of which provides unique features capable to identify, quantify, and resolve ambiguities by selecting appropriate ionization and acquisition parameters. We discuss in this review the use of LC coupled to (quadrupole) time-of-flight mass spectrometry (LC-(Q)ToF-MS) to determine the presence of target and non-target pesticides in water and food. This technique is characterized by operating at a resolving power of 10,000 or more. Therefore, it gives accurate masses for both parent and fragment ions and enables the measurement of the elemental formula of a compound achieving compound identification. In addition, the combination of quadrupole-ToF permits tandem mass spectrometry, provides more structural information, and enhances selectivity. The purpose of this article is to provide an overview on the state of art and applicability of liquid chromatography time-of-flight mass spectrometry (LC-ToF-MS), and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) for the analysis of pesticides in environmental matrices and food. The performance of such techniques is depicted in terms of accurate mass measurement, fragmentation, and selectivity. The final section is devoted to describing the applicability of LC-(Q)ToF-MS to routine analysis of pesticides in food matrices, indicating those operational conditions and criteria used to screen, quantify, and identify target and "suspected" pesticides and their degradation products in water, fruits, and vegetables. The potential and future trends as well as limitations of LC-(Q)ToF-MS for pesticide monitoring are highlighted.

Chromatography, High Pressure Liquid↗

Cigarette smoking and Parkinson's disease: a case-control study in a population characterized by a high prevalence of pesticide exposure.

Epidemiological studies have been consistent in showing that cigarette smoking is inversely associated with Parkinson's disease (PD), whereas pesticide use is positively associated with PD. However, the relationship between PD and cigarette smoking remains poorly understood. Our objective was to study the relationship between cigarette smoking and PD in a population characterized by a high prevalence of pesticide exposure. This case-control study was carried out among subjects enrolled in the Mutualite Sociale Agricole, the French health insurance organization for workers connected to the agricultural world. We included 247 cases and 676 controls matched on age, sex, and region of residency. Information on smoking was obtained through in-person interviews. Pesticide exposure was assessed using a case-by-case expert evaluation procedure. We found an inverse relationship between ever cigarette smoking and PD (odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4-0.9). The strength of this association increased with the number of pack-years. This relationship was present even when smoking was considered as long as 40 years before PD onset. An inverse association was also present among subjects professionally exposed to pesticides (OR = 0.5; 95% CI = 0.3-0.8) and was independent of the duration of exposure among men. We confirm the inverse association between cigarette smoking and PD in a population characterized by a high prevalence of professional pesticide exposure. The relationship between PD and cigarette smoking was not significantly modified or confounded by exposure to pesticides.

Adult↗

Simulation of pesticide leaching in a cracking clay soil with the PEARL model.

Testing of pesticide leaching models is important to increase confidence in their use in pesticide registration procedures world-wide. The chromatographic PEARL model was tested against the results of a field leaching study on a cracking clay soil with a tracer (bromide), a mobile pesticide (bentazone) and a moderately sorbing, persistent pesticide (imidacloprid). Input parameters for water flow and solute transport were obtained from site-specific measurements and from literature. The model was tested using a stepwise approach in which each sub-model was sequentially and separately tested. Uncalibrated simulations for the water flow resulted in moisture profiles that were too wet. Calibration of the hydraulic relationships resulted in a good description of the moisture profiles. Calibration of the dispersion length was necessary to obtain a good description of bromide leaching. The calibrated dispersion length was 61 cm, which is very long and indicates a large non-uniformity of solute transport. The half-life of bentazone had to be calibrated to obtain a good description of its field persistence. The calibrated half-life was 2.5 times shorter than the half-life derived from the laboratory studies. Concentrations of bentazone in drain water and groundwater were described reasonably well by PEARL. Although measured and simulated persistence of imidacloprid in soil corresponded well, the bulk of the imidacloprid movement was overestimated by PEARL. However, imidacloprid concentrations in drain water were underestimated. In spite of the extensive calibration of water flow and tracer movement, the behaviour of the moderately sorbing pesticide imidacloprid could not be simulated. This indicates that the convection-dispersion equation cannot be used for accurate simulation of pesticide transport in cracking clay soils (even if extremely long dispersion length is used). Comparison of the model results from a poorly sorbed chemical (bentazone) and a moderately sorbed chemical (imidacloprid) were useful in defining the limitations of using a chromatographic flow model to simulate the effects of preferential flow.

Benzothiadiazines↗

The POCER indicator: a decision tool for non-agricultural pesticide use.

Pesticides are used not only in agriculture but also by public services and households. Much information is available on the influence of agricultural applications on human health by occupational exposure and on the environment. There is still a need for adequate information on the impact of non-agricultural applications of pesticides. The POCER indicator (Pesticide Occupational and Environmental Risk indicator) has been developed at Ghent University for agricultural situations, as a tool for applicators and decision-makers, by calculating the impact of pesticide treatments on the applicator, the worker, the bystander, groundwater, surface water, bees, earthworms, birds, useful arthropods and persistence in soil. A few adaptations in the POCER calculation method can make the indicator also very useful for non-agricultural conditions. The impact of plant protection products on human health and environment in public services and households can be calculated and the scores can be compared with each other, resulting in an improved pesticide programme. Decision makers might use the POCER indicator to evaluate the reduction programme of public services and communities and offer them measurements to reduce the impact of pesticides. For example, wearing protective clothing or taking into account the distance between application and surface water can greatly reduce the impact score.

Decision Support Techniques↗

Selectivity of pesticides used on cotton (Gossypium hirsutum) to Trichogramma pretiosum reared on two laboratory-reared hosts.

The side-effects of pesticides (insecticides, fungicides, herbicides and plant growth regulators) used on cotton were tested on adults and pupae of Trichogramma pretiosum Riley reared in the laboratory on two different hosts, the Angoumois grain moth (Sitotroga cerealella Olivier) and the Mediterranean flour moth (Ephestia kuehniella (Zeller)). The eggs of the host enclosing the parasitoid pupae received direct pesticide sprays, while the adults of the parasitoid were exposed to the pesticides through contact with residues on sprayed eggs offered to parasitism. Alpha-cypermethrin, carbosulfan, deltamethrin, endosulfan, profenofos and zeta-cypermethrin were highly noxious to the parasitoid, significantly reducing the percentage of emergence and parasitism of T. pretiosum developing in E. kuehniella or S. cerealella eggs. However, the pupal stage of the parasitoid developing in S. cerealella eggs was less susceptible to alpha-cypermethrin and deltamethrin. Lufenuron and metamidophos greatly reduced the percentage of adult emergence from eggs of both hosts, while novaluron only interfered on this variable when the wasps were developing in E. kuehniella eggs. However, lufenuron and monocrotophos had no effect on the parasitoid pupae of T. pretiosum developing in E. kuehniella eggs. Chlorfluazuron, diafenthiuron, diflubenzuron, fentin hydroxide, mepiquat chloride, novaluron, thiacloprid and triflumuron did not affect T. pretiosum emergence when eggs of S. cerealella enclosing pupae of the wasps were surface treated. The pesticides azoxystrobin, carbendazin + thiram, mepiquat chloride and novaluron had no effect on the ability of the wasps to parasitise E. kuehniella eggs. However, only mepiquat chloride did not affect the percentage of F1 wasps emerging from E. kuehniella eggs. The remaining pesticides moderately reduced the percentage of emergence and parasitism of the wasps when they had contact with the chemicals during their pupal or adult stage. Thus there were differences in pesticide toxicity according to the host used for parasitoid development. These differences were hypothesised to occur because of differences in egg morphology and parasitoid performance.

Animals↗

Harmonised pesticide risk trend indicator for food (HAPERITIF): The methodological approach.

To provide a harmonised European approach for pesticide risk indicators, the Sixth EU Framework Programme recently financed the HAIR (HArmonised environmental Indicators for pesticide Risk) project. This paper illustrates the methodology underlying a new indicator-HAPERITIF (HArmonised PEsticide RIsk Trend Indicator for Food), developed in HAIR, for tracking acute and chronic pesticide risk trends for consumers. The acute indicator, HAPERITIF(ac), is based on the ratio between an estimated short-term intake (ESTI), calculated as recommended by the World Health Organisation (WHO), and the acute reference dose (ARfD); the chronic indicator HAPERITIF(chr) is based on the ratio between an estimated daily intake (EDI) and the admissible daily intake (ADI). HAPERITIF can be applied at different levels of aggregation. Each level gives information for proper risk management of pesticides to reduce the risk associated with food consumption. An example of application using realistic scenarios of pesticide treatments on a potato crop in central-northern Italy is reported to illustrate the different steps of HAPERITIF.

Environmental Monitoring↗

Factors affecting the phase-out of pesticide use in public areas in Denmark.

That pesticide use in public areas in Denmark has been significantly reduced during the period 1995 to 2002 is shown when comparing three surveys carried out by the Danish Forest and Landscape Research Institute (DFLRI) with funding from the Danish Environmental Protection Agency. During that period, the total registered public use of pesticides was reduced from 28.8 tonnes active ingredients to 6.3 tonnes, corresponding to a 78% reduction. In 2002, the Danish counties and state institutions had reduced their total pesticide use by 80% and 73%, respectively, compared to 1995 figures. Similarly, the Danish municipalities reduced their use by 83% from 1995 to 2002. Surveys of municipal pesticide use carried out in 1995, 2000 and 2002 have been used as the basis for determining the factors that have influenced municipal reductions of pesticide use. The 2000 and 2002 trends can be explained partly on the basis of the figures for 1995 use. The trend for 2002 can also be partially explained by the political parties in power in the municipalities during the phase-out period. The models used account for up to 30% of the total variations, meaning that the pesticide use of individual municipalities is very much influenced by other, non-definable factors such as tradition.

Agriculture↗

Concentrations of pesticide residues in tissues of fish from Kolleru Lake in India.

Kolleru Lake is the largest natural freshwater lake of Andhra Pradesh in India. It is situated between latitudes 16 degrees 32' and 16 degrees 47'N and longitudes 81 degrees 05' and 81 degrees 27'E. The use of pesticides for agricultural purposes is widespread in the Kolleru Lake region. The biological indicators like fish help in the studies of aquatic pollution by pesticides. Fish species Channa striata and Catla catla and water samples were collected from Kolleru Lake in each of three seasons over a period of three years. Fish samples were analyzed according to a modified method which is proposed for the gas chromatographic determination for the pesticides viz., alpha-BHC, gamma-BHC, malathion, chloirpyrifos, isodrin, endosulfan, dieldrin, and p,p-DDT. Water samples were analyzed for selected physico-chemical parameters. The extraction efficiency for the selected pesticides is between 82.8% and 91.2%. The maximum concentrations of pesticide residues in Kolleru Lake fish on wet weight basis are 123.8 micrograms/g for alpha-BHC, 98.7 micrograms/g for gamma-BHC, 2.5 micrograms/g for malathion, 88.6 micrograms/g for chlorpyrifos, 0.91 microgram/g for isodrin, 76.5 micrograms/g for endosulfan, 1.98 micrograms/g for dieldrin, and 157.4 micrograms/g for p,p'-DDT. These analyses were used to evaluate the baseline data and the pesticide pollution in the lake's ecosystem.

Agriculture↗

A model for predicting the frequency of high pesticide exposure events in the Agricultural Health Study.

The frequency of self-reported high pesticide exposure events (HPEE) has been recorded in the NCI/EPA/NIEHS Agricultural Health Study (AHS). Fourteen percent (14%) of the enrolled applicators responding reported "an incident or experience while using any pesticide which caused an unusually high exposure." These data show, as expected, that the probability of a report of an HPEE increases with the cumulative number of days of pesticide application reported by the applicator. We have developed a three-parameter model that predicts the risk odds ratio (OR) of an HPEE as a function of the number of days that pesticides are applied. These events are costly in terms of resulting health-care visits, lost time from work, and potential risk for cancer and other chronic diseases. We propose that failure to carefully follow all the pesticide manufacturer's label requirements, inexperience, and random events (i.e., breaking hose) are the three factors responsible for the events observed. Special precautions for new or infrequent users of pesticides are indicated.

Agriculture↗

Biomarkers of pesticide exposure.

Incorporation of biomarkers in studies of occupational exposure hazards is now recognized as a highly useful adjunct to the surrogate measures employed in the past, for example, time worked, ambient air data, interview responses. Application to studies of workers potentially exposed to pesticides has barely begun and provides many challenges to chemist/epidemiologist teams. This review indicates several excellent studies employing multiple-exposure measures to document the validity of specific biomarkers for particular exposure situations. In general, exposure reflected by urinary assays of specific pesticides is a low percentage of that indicated by dermal or breathing zone measures. Markers for many of the pesticides in current usage have yet to be developed and validated, and information on population variability is generally lacking for existing markers. The challenge provided by the complexity of multiple, and often unknown, exposures to individuals in pesticide environments has begun to be addressed employing cytogenetic or urinary measures that attempt to integrate these complex exposures. The lack of data regarding sensitivity and specificity of biomarkers, especially in complex exposure situations, is a major problem that perhaps will best be addressed by studies combining nonspecific measures with specific ones, utilizing stored sample banks created for that purpose. Expanding the repertoire of available biomarkers of pesticide exposure and employing multiple ones in well-designed study protocols will provide critical tools in the evaluation of pesticide safety and design of appropriate measures to minimize adverse exposures. Ironically, one of the problems that biological markers of exposure can help overcome, reliance on poorly measured ambient exposure data, hampers the evaluation of the markers themselves. Therefore, the combination of in vitro, animal, and human data will give the best picture of a marker's performance. (Wilcosky 1990).

Biomarkers↗

Toxicological-hygienic requirements for study, registration, and regulations of pesticides in the USSR.

This review discusses the toxicological and hygienic aspects of the extensive increase in pesticide use, which has resulted in the great majority of people throughout the world being affected by their presence. The need for a broad exchange at an international level of the findings of toxicological and hygienic research is established. Brief information on the development of pesticide toxicological research in the USSR is also presented. Accepted criteria for toxicological and hygienic pesticide assessments in the USSR are also systematically reviewed, with respect to the evaluation of physical and chemical properties, toxicity as defined through acute and subacute experiments, cumulative properties, and effects on skin and mucous membranes. The methodology for establishing threshold and noneffective (harmless) levels is also described, along with the prediction of delayed adverse effects. Other areas discussed include the classification of pesticides by degree of toxicity and danger, the system of research and regulation in the USSR, and the principle of integrated standardization of pesticide content of food, water, and atmospheric air. The review concludes with a look at certain prospective trends in the search for and development of pesticides that have selective action on target organisms but are harmless to human health and the environment.

Animals↗

Evaluation of the genotoxic potential of certain pesticides used in Pakistan.

The mutagenicity of fifteen insecticides, five fungicides, four herbicides, and an acaricide commonly used in Pakistan was evaluated by employing thirteen short-term bioassays. The genetic endpoints used included point or gene mutation, primary DNA damage, and chromosomal effects. Initially, all pesticides were tested in a "core" battery of four in vitro bioassays. A carefully selected group among these chemicals was retested in higher level test systems to confirm the results obtained in the initial phase. Of the pesticides tested, only a small portion consistently displayed mutagenicity across test systems. The Saccharomyces cerevisiae bioassays detected mutagenicity for the largest number of pesticides. The Salmonellaces typhimurium strain, TA100, was able to detect genetic activity in all of the pesticides that produced positive results in this bioassay. The cytogenetic effects observed from the Vicia faba root assay were consistent with those obtained in mammalian cells in culture. All pesticides which displayed mutagenicity were not carcinogenic in animal bioassays but, in general, mutagenicity in a battery of short-term bioassays was a reliable indicator of the carcinogenic potential in animals. A simple test battery is proposed for evaluating the genetic potential of agricultural pesticides.

Animals↗

Predicting pesticide residues to reduce crop contamination.

The system of dynamics between pesticides and plants is reviewed, and a conceptual model capable of reflecting the necessary qualitative and structural peculiarities is proposed as a means of predicting residue levels. The degradation processes of various chemical classes of pesticides in plants under different conditions of use are analyzed. Formulas are developed that enable recognition and estimation of residue levels and duration of retention for "new" pesticides and "old" substances under varying treatment conditions. Estimated data are verified to provide positive assessments of the accuracy of the predictions. Mathematical modeling as a means of perception is stressed. With this method, the outlet value can be controlled by changing such inlet parameters as application rate, frequency of treatments, types of plants, and so on. Residue levels are predicted for different combinations of use conditions in various climatic-geographical regions. The method of estimation also enables the development of important standards such as post-treatment waiting intervals. A more flexible technique can be employed, in which specific periods are established for different plants under various treatment conditions. Thus, both unjustified shortened waiting intervals or unnecessarily elongated intervals periods can be avoided. The greatest value of the modeling approach is that information can be obtained on the degree of potential food contamination and major standards can be developed without the need for extensive experimental use of pesticides under actual conditions. This technique fully considers optimal use conditions for agrochemicals in terms of human requirements and protection of plants. Mathematical modeling protects the environment while enabling the speedy selection of safe parameters for pesticide use conditions nd realization of significant savings in manpower and time. Overall, this estimation method appears to be an efficient link in the broad system of preventing environmental pesticide contamination and protecting human health.

Humans↗

Validity of toxicity documents of pesticides and good laboratory practice.

Attention has been centered on the validity of the original toxicity reports supporting the registration of pesticides. In Finland, the present standard of the toxicity reports on pesticides was studied. Of the 299 pesticide formulations on the Finnish market only 96 were supported by original toxicity reports. Altogether 16 US formulations and 121 reports, as well as 11 control formulations with 170 reports were selected for the study. Reports from the questionable laboratories proved to be invalid according to the OECD guide-lines more frequently (61%) than those from control laboratories (20%). The frequency of invalid reports among long-term studies was higher (38%) than among acute studies (26.4%). The percentage of valid toxicity studies for the registration of pesticides in Finland was increased from about 50% in the fifties and sixties to 93% in 1980. The lack of reports on old pesticide formulations rather than the validity of the toxicity reports creates a problem in pesticide registration in Finland.

Animals↗

Organochlorine pesticide contamination in neotropical migrant passerines.

Organochlorine pesticide levels were determined in Neotropical migrant passerines which have populations reported to be declining. Pesticide residues ranging from 0.385 to 27.4 ng/g were found in 19 of 21 birds, including both Hatch Year (HY) and After Hatch Year (AHY) age classes of nine different species. Eighteen of the 19 birds contained p,p'-DDE, while dieldrin was found in 16 birds and heptachlor epoxide was present in 10 birds. There were no significant differences in pesticide levels between HY and AHY birds, suggesting that HY birds are exposed to pesticides in their diet on the breeding ground or that pesticides are acquired from contaminated mothers, or both. Pesticide levels were not related to gender. Although the effects of these low residue levels on passerine fecundity are unknown, their presence has potential conservation implications for passerines and for the raptorial birds that feed upon them.

Animals↗