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PubMed2004

Bound and unextractable pesticidal plant residues: chemical characterization and consumer exposure.

Plants are well known to incorporate pesticides into bound and unextractable residues that resist solubilization in common laboratory solvents and are therefore not accessible to standard residue analysis. A characterization of such residues has been proposed for incorporation rates above trigger values of 0.05 mg kg(-1) parent pesticide equivalents, or percentage values of 10% (United States Environmental Protection Agency, 1995) or 25% (Commission of the European Communities, 1997) of the total radioactive residue. These trigger values are often exceeded. The present review describes the current status of the chemical characterization and animal bioavailability of bound and unextractable residues that may be xenobiotic in nature or result from natural recycling of simple degradation products. The latter case represents a mechanism of detoxification. Bound residues have been shown to be covalent or non-covalent in nature. With regard to the plant matrix molecules involved, incorporation into proteins, lignins, pectins, hemicelluloses and cutins has been demonstrated, and four covalent linkage types are known. Animal feeding experiments have revealed cases of low as well as high bioavailability. Many of the studies are limited by experimental uncertainties and by results only being reported as relative percentage values rather than absolute exposure. A preliminary value of absolute exposure from bound and unextractable residues is derived here for the first time from eight case studies. The mean exposure (ca 1.5 mg kg(-1) pesticidal equivalents) exceeds some of the existing maximum residue levels (MRLs) of residual free pesticides that are typically in the range of 0.05-1 mg kg(-1). A mathematical framework for the correction of current maximum residue levels is presented for cases of highly bioavailable bound residues. As bound pesticidal residues in food plants could represent a source of significant consumer exposure, an experimental test scheme is proposed here. It consists of basic chemical characterization, model digestibility tests and, in exceptional cases, animal bioavailability and additional toxicological studies.

Animals↗

PubMed2005

A preliminary assessment of consumer's exposure to pesticide residues in fisheries products.

The fisheries products in this study comprise fish, bivalve, crustacean and cephalopod collected from different types of markets in Taiwan between the years 2001 and 2003. A total of 91 pesticide residues belonging to four major pesticide groups were tested and analyzed. The test results show that 65.40% of fish, 93.55% of shellfish, 84.92% of crustacean and 98.33% of cephalopod samples contain no detectable residues. There are only two kinds (organochlorine and organophosphate) of totally six pesticides (DDTs, dieldrin, chlorpyrifos, fenitrotion, fenthion and prothion) that have been detected from the fisheries products in this study. For there were pesticides present in the fish products, consumption of fisheries product there was no zero risk. But the exposure of consumer did not exceed the acceptable daily intakes (ADI). For male, there was the highest risk in exposure to dieldrin, which the percentage of ADI was 93.56%. This study also suggests that a yearly monitoring program for organophosphate pesticide residues in fish is necessity.

Animals↗

PubMed2004

Surface photochemistry of pesticides: an approach using diffuse reflectance and chromatography techniques.

The photochemistry of pesticides triadimenol and triadimefon was studied on cellulose and beta-cyclodextrin (beta-CD) in controlled and natural conditions, using diffuse reflectance techniques and chromatographic analysis. The photochemistry of triadimenol occurs from the chlorophenoxyl moiety, while the photodegradation of triadimefon also involves the carbonyl group. The formation of 4-chlorophenoxyl radical is one of the major reaction pathways for both pesticides and leads to 4-chlorophenol. Triadimenol also undergoes photooxidation and dechlorination, leading to triadimefon and dechlorinated triadimenol, respectively. The other main reaction process of triadimefon involves alpha-cleavage from the carbonyl group, leading to decarbonylated compounds. Triadimenol undergoes photodegradation at 254 nm but was found to be stable at 313 nm, while triadimefon degradates in both conditions. Both pesticides undergo photochemical decomposition under solar radiation, being the initial degradation of rate per unit area of triadimefon 1 order of magnitude higher than the observed for triadimenol in both supports. The degradation rates of the pesticides were somewhat lower in beta-CD than on cellulose. Photoproduct distribution of triadimenol and triadimefon is similar for the different irradiation conditions, indicating an intramolecular energy transfer from the chlorophenoxyl moiety to the carbonyl group in the latter pesticide.

Adsorption↗

PubMed2002

Toxicological studies in tropical ecosystems: an ecotoxicological risk assessment of pesticide runoff in South Florida estuarine ecosystems.

A multiyear study in the C-111 canal system and associated sites in Florida Bay was undertaken to determine the potential pesticide risk that exists in South Florida. After the examination of extensive pesticide concentration data in surface water, tissues, and semipermeable membrane devices (SPMDs), canal contamination seems to be derived from the extensive agricultural production that drains into the C-111 canal. The results of this study indicate that runoff from agricultural processes led to quantifiable pesticide residues in both canal and bay surface water, which occasionally exceeded current water quality criteria. The major pesticide of concern was endosulfan, which was detected at 100% of the sites sampled. Endosulfan exposure did not cause any acute effects in fish and crustaceans deployed in field bioassays. Chronic effects were observed in copepods, clams, and oysters but could not be attributed to endosulfan exposure. The decision to alter the C-111 canal flow and allow increased freshwater flow into the adjacent Everglades National Park may result in discharges of pesticides into the Everglades. Continued monitoring in this area is needed during this change in flow regime.

Agriculture↗

PubMed1998

Health of tree swallows (Tachycineta bicolor) nesting in pesticide-sprayed apple orchards in Ontario, Canada. I. Immunological parameters.

The degree of pesticide exposure and its effects on the immune system and its development were determined in 16-d-old tree swallow (Tachycineta bicolor) chicks from 4 sprayed apple orchards and three nonsprayed sites in southern Ontario, Canada, during 1994-1995. Persistent contaminant residues were measured in tree swallow eggs and in each chick hepatic ethoxyresorufin O-deethylase (EROD) activity; body, immune organ, and liver masses; lymphocyte blastogenesis response; respiratory burst and phagocytic responses; hemarological evaluation; and histological development of thymus, bursa of fabricius, and spleen were determined. Chemicals sprayed on apple orchards were mainly ethylene bisdithiocarbamate and myclobutanil fungicides and organophosphorus, carbamate, and synthetic pyrethroid insecticides. During the period between oviposition of the first egg in each nest to d 16 after hatching, individual nests in orchards were exposed to between 4 and 11 individual chemical applications and up to 3 mixtures of pesticide sprays. Concentrations of pesticides, polychlorinated biphenyls (PCBs), and lead and arsenic residues in tree swallow eggs and liver were low and not variable among sites except p,p'-DDE, which was as high as 2.29 microg/g wet weight in eggs. EROD activity was not different among sites. Organochlorine and trace metal residues and EROD activity were not correlated with any immune parameter. In sprayed birds, we found a significantly increased blastogenic response to pokeweed mitogen (12.5 microg/ml). However, nests were initiated over a period of several weeks and we also found changes in other tree swallow immune parameters that were related to the date of chick collection. Hematological parameters, bursal and thymic masses, phagocytic response, and thymic development were all correlated with the day the chicks were 16 d of age. After accounting for the collection date of birds from each nest, we found cell proliferation in the cortex and delayed thymic involution correlated positively with increasing spray exposure. We also found that birds in sprayed orchards were slightly anemic compared to birds from nonsprayed sites, and there were smaller bursal masses and an increase in relative heterophil concentrations in the sprayed orchard birds. The local inflammation may have been caused by trematode parasite infections, although pesticide exposure also correlated positively with these parameters. This is the first study of the immunology and effects of current pesticide exposures in wild passerines; therefore it is difficult to predict the long-term consequences of the apparent stimulated immune systems in sprayed birds. However, some environmental contaminants that overtly stimulate the immune system in mammals have induced hypersensitivity and/or autoimmunity. Therefore we speculate that these effects are possible in tree swallows.

Animals↗

PubMed1989

Demographic and seasonal influences on human serum pesticide residue levels.

This study was intended to characterize more fully the distribution of serum concentrations of 16 pesticide residues with regard to key demographic and seasonal variables in a subsample of persons from the Second National Health and Nutrition Examination Survey between the ages of 12 and 74 yr old. Blood sera in 2-ml aliquots were analyzed, and the results were confirmed for 5994 persons. Almost all participants (99.5%) had p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) concentrations greater than or equal to 1 ppb, ranging as high as 378.6 ppb. For the other pesticide residues, only beta-benzene hexachloride (beta-BHC) (quantified in 17.2% of the sera), dieldrin (10.6%), and another DDT-related residue, p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) (35.7%) were found at quantifiable levels in more than 10% of the serum specimens. Of the remaining analytes, hexachlorobenzene (HCB), trans-nonachlor (TNC), and heptachlor epoxide (HE) were found at quantifiable concentrations in 1-10% of the specimens, whereas o,p'-DDT, o,p'-DDE, p,p'-DDD, mirex, alpha-BHC, gamma-BHC, heptachlor, delta-BHC, and aldrin were found in less than 1% of the serum specimens. Results showed that increasing age, residing on a farm, or being a male conferred increased risks of exposure to most of the pesticide residues, independent of all other demographic and seasonal factors. In a pattern less consistent across the different pesticide residues and for fewer of the pesticides, persons who lived below the national poverty level, were nonwhite, resided in the South or West, or were examined in the spring or winter also seemed to have an increased likelihood of having quantifiable serum levels.

Adolescent↗

PubMed1980

Nutritional implications of pesticides in foods.

Pesticides having a rapid and positive influence on the quantity of produced food, at the same time are involved in several side effects, often creating some hazard to human health and well-being. The authors show these facts in view of the possible entrance of these substances into the food chain, and present several actions or measures undertaken by various organizations, especially UN Agencies. The main emphasis is laid down on pesticides residues which remain in consumed food, based on the experience gained in different countries including Poland. From the toxicological or health point of view, it is important to know whether these substances interact with other nutrients entering plant or animal tissues or whether they remain on the surface, being easily removed before human consumption. Some effects of processing on decreasing the content of these residues in foodstuffs are also briefly outlined. Another aspect connected with the application of pesticides is their influence (mainly negative) on the nutritive value of harvested plants. In conclusion, the authors call for more attention and a complex approach in using pesticides for plant and animal protection as well as basic and applied nutrition, or health-oriented research along with training activity within national or rather international (e.g. UN Agency) programmes. They should be aimed at the optimal application of pesticides on modern agricultural practices with the main emphasis on their nutritional implication.

DDT↗

PubMed1978

Overview of potential mutagenic problems posed by some pesticides and their trace impurities.

This review principally addresses a number of aspects of usage of pesticides as well as populations at potential risk and attempts to highlight categories of pesticides whose structures or those of their metabolites and/or trace impurities, degradation and transformation products suggest an a priori mutagenic and/or carcinogenic risk. The pesticides considered include: DDT, hexachlorobenzene (HCB), 2,4,5-T, pentachlorophenol, and various herbicidal precursors (e.g., carbamates, triazines) of nitrosamines and nitroso derivatives. Structural features of a number of halo-unsaturated pesticides (e.g., dichloropropenes) were also reviewed from a viewpoint of contrasting their potential mutagenicity with that of vinyl chloride and vinylidene chloride. Additionally the mutagenicity of the organophosphorus pesticide Trichlorophon is contrasted with that of its degradation products.

Animals↗

PubMed2006

A case for revisiting the safety of pesticides: a closer look at neurodevelopment.

The quality and quantity of the data about the risk posed to humans by individual pesticides vary considerably. Unlike obvious birth defects, most developmental effects cannot be seen at birth or even later in life. Instead, brain and nervous system disturbances are expressed in terms of how an individual behaves and functions, which can vary considerably from birth through adulthood. In this article I challenge the protective value of current pesticide risk assessment strategies in light of the vast numbers of pesticides on the market and the vast number of possible target tissues and end points that often differ depending upon timing of exposure. Using the insecticide chlorpyrifos as a model, I reinforce the need for a new approach to determine the safety of all pesticide classes. Because of the uncertainty that will continue to exist about the safety of pesticides, it is apparent that a new regulatory approach to protect human health is needed.

Environmental Exposure↗

PubMed2001

Assessing the potential for pesticide leaching for the pine forest areas of Tenerife.

Currently, no guidelines cover use of pesticides in the forested areas of the Canary island of Tenerife. An index-based model (Li) was used to rank the leaching potential of 50 pesticides that are, or could be, used for management purposes in the pine forest areas of Tenerife. Once the pesticides with the greatest leaching potential were identified, regional-scale groundwater vulnerability assessments, with consideration for data uncertainties, were generated using soil, climatic, and chemical information in a geographic information system framework for all pine forest areas of the island. Process-based simulations with the pesticide root zone model for the areas and pesticides of highest vulnerability were conducted to quantitatively characterize the leaching potentials. Carbofuran, hexazinone, picloram, tebuthiuron, and triclopyr were each identified as being potential leachers.

Agriculture↗

PubMed1979

Cut flowers: a potential pesticide hazard.

Following reports of ten cases of possible organophosphate pesticide poisoning in florists exposed to pesticide residues on cut flowers, we conducted a prospective random-sample survey to determine residual pesticide levels on flowers imported into the United States via Miami, Florida. A sample of all flowers imported into Miami on three days in January 1977 showed that 18 (17.7 per cent) of 105 lots contained pesticide residue levels greater than 5 ppm, and that three lots had levels greater than 400 ppm. Azodrin (monocrotophos) was the most important contaminant with levels of 7.7--4,750 ppm detected in nine lots. We examined 20 quarantine workers in Miami and 12 commercial florists exposed to contaminated flowers. Occasional nonspecific symptoms compatible with possible organophosphate exposure were noted, but we found no abnormalities in plasma or red blood cell cholinesterase levels. This study documents a previously unrecognized potential source of occupational pesticide exposure and suggests that safety standards should be set for residue levels on cut flowers.

Adult↗

PubMedDate not supplied

Validation of a fast and easy method for the determination of residues from 229 pesticides in fruits and vegetables using gas and liquid chromatography and mass spectrometric detection.

Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10-100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid-liquid partitioning step performed by adding 6 g anhydrous MgSO4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO4, which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70-120% (90-110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods.

Acetone↗

PubMedDate not supplied

Screening and evaluation of fruit samples for four pesticide residues.

The occurrence of 4 pesticide residues, imidacloprid, carbendazim, methiocarb, and hexythiazox, was assessed in several fruits (oranges, tangerines, watermelons, and date plums) from the Valencian Community (Spain). A total of 227 samples--56 oranges, 134 tangerines, 13 watermelons, and 24 date plums--were taken from an agricultural cooperative representative of the area studied during 2001. The pesticides were determined by liquid chromatography/mass spectrometry after sample extraction with ethyl acetate and anhydrous sodium sulfate. Recoveries of 4 pesticides at 2 fortification levels (0.02 and 0.2 mg/kg), the lower of which was the quantification limit, ranged from 60 to 108%. Concentrations of imidacloprid, carbendazim, methiocarb, and hexythiazox ranged from 0.02 to 0.75 mg/kg in 184 samples (54 oranges, 119 tangerines, 3 watermelons, and 8 date plums). Nineteen samples contained methiocarb or hexythiazox residues that exceeded the maximum residue limits. Calculation of the estimated daily intakes of the 4 pesticides studied and their comparison with the Acceptable Daily Intakes established by the Food and Agriculture Organization of the World Health Organization demonstrated the safety of fruit consumption and showed the importance of monitoring for pesticide residues.

Benzimidazoles↗

PubMed2006

[Residues and distribution character of organochlorine pesticides in stream sediments in southwestern suburb of Nanjing].

Sediments and water samples were collected from different cross sections of 4 tributaries of Yangtze River in southwestern suburb of Nanjing city in spring 2004, and agricultural soil sample were collected also in those valleys. The residues and distribution of organochlorine pesticides in sediments from different streams were determined and the influence of soil character on organochlorine pesticides residues in sediments were studied. Result showed that accumulation of HCHs and DDTs occured significantly in the sediments and related to soil erosion. Residues of organochlorine pesticides in sediments may be influenced obviously by pH of agricultural soil in the valleys. In the alkaline soil, organic matters could be leached easily and entered the stream water and accumulated into sediments, resulting in accumulation of organochlorine pesticides adsorbed on soil organic matters in sediments. In the transfer process of materials from soil to water and sediment, constitutes of organochlorine pesticides in multiphase environmental medium were changed; usually those components easily leached from soils had higher residue levels in sediments. Meanwhile, sedimentation of soil in streams could reduce OCPs input to the Yangtze River.

China↗

PubMed2006

[Simultaneous determination of multiresidual pesticides in vegetables and fruit by high performance liquid chromatography].

A high performance liquid chromatographic (HPLC) method for simultaneous determination of 12 pesticides in vegetable and fruit samples was developed and evaluated. The analytical procedure involved in ultrasonic extraction with ethyl acetate, purification using a Florisil SPE column (6 mL, 1000 mg) and n-hexane-dichloromethane (1 : 1, v/v). The eluate was blown to dryness under a stream of nitrogen and the residue was dissolved in 0.10 mL of methanol, followed by separation and quantitative analysis by using reversed-phase HPLC with gradient elution for the baseline separation of the 12 pesticides and programmed ultraviolet wavelength shift detection in 32 min. The detection limits of the 12 pesticides ranged from 0.14 to 2.65 ng. The average recoveries ranged from 62.2% to 118.2% with the relative standard deviation (RSD) range of 0.56%-11.8% for the spiked fruit samples, and from 52.1% to 124.6% with RSD range of 0.89%-18.4% for the spiked vegetables. The method was applied to determining multiresidual pesticides in vegetables and fruit for a total of 40 samples. It is concluded that this method is rapid, accurate, sensitive and reproducible for determining trace pesticides in vegetable and fruit samples.

Chromatography, High Pressure Liquid↗

PubMed1979

Optimal timing of multiple applications of pesticides with residual toxicity.

Optimal timing of pesticide applications depends upon many factors including pest population demography, crop susceptibility to damage, weather and the rate at which a pesticide loses its toxicity. An efficient numerical optimization procedure incorporating these factors is developed and applied to the control of the Egyptian alfalfa weevil [Hypera Brunneipennis (Boheman)]. The procedure differs from earlier approaches in that the state vector describes the schedule of previous pesticide applications. Population density and age structure are used indirectly in construction of an equation which estimates pest damage to the crop as a function of the state vector. This approach can be used to calculate optimal timing of multiple pesticide applications based on a more detailed population model than previously has been possible. Calculation of the optimal pesticide application schedule with 11 age classes and 28 decision periods required only 25 seconds of CPU time on an IBM 370/168 computer.

Animals↗

PubMed2003

National Health Interview Survey mortality among US farmers and pesticide applicators.

BACKGROUND: The mortality experience of pesticide-exposed workers across the US has not been thoroughly studied. METHODS: Cox regression mortality analyses adjusted for the complex sample survey design were performed on mortality-linked 1986-1994 National Health Interview Survey (NHIS) data. RESULTS: Nine thousand four hundred seventy-one farmers and pesticide applicators with 571 deaths were compared to 438,228 other US workers with 11,992 deaths. Age-adjusted risk of accidental death, as well as cancers of the nervous and lymphatic/hematopoietic systems, was significantly elevated in male and female pesticide-exposed workers; breast, prostate, and testicular cancer mortality risks were not elevated. CONCLUSIONS: Compared to all other workers, farmers and pesticide applicators were at greater risk of accidental mortality. These pesticide-exposed workers were not at an increased risk of cancers possibly associated with exposure to estrogen analogue compounds, but were at an increased risk of hematopoietic and nervous system cancers. NHIS mortality follow-up represents an important occupational health surveillance instrument.

Accidents↗

PubMed2005

Measuring success in a pesticide risk reduction program among migrant farmworkers in Colorado.

BACKGROUND: Farmworkers in the US largely consist of young undocumented Hispanics with a median education of 6 years and limited English skills. The High Plains Intermountain Center for Agricultural Health and Safety bilingual pesticide risk reduction program, which complied with the Worker Protection Standard for migrant farmworkers was evaluated. METHODS: A pretest/posttest comparison of farmworkers (n = 152) assigned to either the experimental or control group was used. Independent variables included demographics, agricultural experience, and health locus of control. Dependent variables were pesticide knowledge, safety risk perception (SRP), and safety-behavior outcomes. RESULTS: The bilingual pesticide program effectively increased farmworker's pesticide knowledge (P = 0.0001), SRP (P = 0.0001), and two (out of four) behavior outcomes. Workers with external health locus of control were less likely to adopt safety behaviors (P = 0.0001). CONCLUSIONS: The cognitive decision-making process whereby farmworkers' readiness to change and permanently adopt safety behaviors was supported by the pesticide program. Our results support the need for long-term sustained bilingual, intervention programs that demonstrated effectiveness using integrative methodology.

Adolescent↗