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Canadian Total Diet Study in 1998: pesticide levels in foods from Whitehorse, Yukon, Canada, and corresponding dietary intake estimates.

The Canadian Total Diet Study is a national survey to determine the level of chemical contaminants in the Canadian food supply. Food samples were collected from Whitehorse, Yukon, supermarkets as part of the study in 1998. Whitehorse was chosen as a sampling centre, despite its small population (n = 19,000), to determine if residue levels were different in foods available in northern communities relative to levels observed in previous studies in the more populated south. Foods were prepared as for consumption before pesticide residue analysis. Residue levels observed in most foods were similar to levels observed in samples from previous surveys from southern Canadian cities. Malathion and DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), a transformation product of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl(ethane), were the two most frequently detected compounds (26.4 and 25.8%, respectively). The majority of pesticides, however, had a detection frequency of < 5%. In general, pesticides in food composites were well below maximum residue limits established in the Canadian Food and Drug Regulations. Chlorpropham and captan had the highest dietary intakes (2.16 and 1.94 micrograms (kg body weight-day)-1, respectively), based on the results from Whitehorse. No dietary intakes above the acceptable daily intakes, however, were observed for any of the 39 pesticides investigated in any age-sex category, where an acceptable daily intake has been proposed.

Adolescent↗

Dietary intake of pesticides: State of Kuwait total diet study.

The State of Kuwait conducted a total diet study (TDS) to determine the dietary intakes of selected pesticides. This paper reports the results of this study. A national food consumption survey was performed and core food lists for different population groups were established representing the total diet of the Kuwaiti population. Food items (table-ready) were purchased/prepared and analysed for their contents of organophosphate/organochlorine carbamate, benzimidazole and phenylurea pesticides according to the US FDA Pesticide Analytical Manual (PAM I). Dietary intakes of these pesticides are presented for 19 population groups, which range from infants to elderly adults. The intakes of selected population groups are compared with representative findings from the US FDA/TDS and data published from other countries. In general, the average daily intakes were well below acceptable limits, but higher than those reported from developed countries.

Adolescent↗

Analysing organophosphorus pesticides in wines using graphitized carbon black extraction cartridges.

A quick and simple method was developed to determine the residues of 15 organophosphorus pesticides of different polarity in grape wine, based on liquid-solid extraction with graphitized carbon black cartridges and capillary gas chromatography. Aliquots of diluted wine (10 ml wine + 40 ml deionized water) and 250 mg graphitized carbon black cartridges were used to extract the analytes. The pesticides were eluted with 2 x 0.5 ml acetone and 3 x 2.5 ml ethyl acetate/acetone (80:20). The eluates were then dried with anhydrous sodium sulphate and concentrated to 1 ml under a nitrogen current. After adding triphenylphosphate internal standard (i.s.), this extract was analysed by capillary gas chromatography using a nitrogen-phosphorus detector (GC-NPD). Pesticide recovery percentages at levels of 0.01 and 0.02 microgram/ml were between 74% and 111%, with a 2-13% relative standard deviation interval. The chromatograms of extracts had few co-extracted species peaks, with no analytical interference. Dilution of the grape wine samples removed most of the pigments, thus producing clear extracts. The results indicate that liquid-solid extraction from wine samples using graphitized carbon is fast (25 min per sample), efficient and reproducible for analysing organophosphorus pesticides of different polarity.

Chromatography, Gas↗

Microencapsulation of pesticides and their improved handling safety.

The purpose of pesticide formulations and recent requirements of pesticide industry are discussed, and the importance of research work on pesticide delivery systems, is pointed out. For this purpose, the microcapsules, as one of the typical controlled release formulations, play an important role. Handling safety of the pesticides is improved considerably by microencapsulation due to hazard and exposure reduction.

Agriculture↗

Impact of long-term pesticide applications on some soil biological parameters.

The soil oxidative and anaerobic processes, as well as, the microbial biomass were followed during three years in a cotton farm (Tatuí) where the recommended pesticides have been used for several years, and in an experimental field (São Paulo) treated first time with the same pesticides. The oxidative process was monitored by the dehydrogenase (DHA)-activity using triphenyltetrazolium chloride (TTC) as substrate. The anaerobic process was followed by the iron-oxide reduction, and the microbial biomass was estimated by the substrate (glucose)-indiced respiration. Increases in DHA-activity and in the microbial biomass occurred only in the farm soil, with concomitant decreases in iron-reduction. In the experimental field soil, the increases in DHA-activity were followed only by decreases in iron-reduction. Soil characteristics were the determining factor for different biological parameters after pesticide inputs. All the pesticides produced at least one clear but transient effect.

Agriculture↗

Dermal exposure to pesticides modifies antioxidant enzymes in tissues of rats.

Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined in rat tissues after dermal exposure to pesticides. Two experiments were conducted in male SD rats, 190-210 g body weight. Acephate (ACP), methamidophos (MAP) and nicotine (NIC) were dissolved either individually or together in 0.25 mL of 50% ethanol, which contained: AP = 12.6 or MAP 1.3 or NIC = 9.6 mg; EXP 1--individual pesticide exposure; 64 rats, 16/group; EXP 2--mixture of AP + MAP + NIC at levels of 1X, 2X, 3X; 48 rats, 12/group; 0.25 mL of solution or ethanol (Controls) was applied to 25 mm2 area of shaved skin 3 times a week. Half the rats were terminated after 4 weeks and the rest after 4 weeks of stopping exposure. Single pesticides decreased erythrocyte (RBC) SOD by 17% after exposure and in the NIC group after post exposure (P#0.05). Increasing concentrations of AP + MAP + NIC mixture elevated RBC SOD by 22% in the 2X and 3X groups and CAT by 13% in the 3X group (P#0.05); post exposure increased RBC SOD by 2-3 fold and CAT activity by 13% in all 3 groups. Liver GPX increased by 30-40% and CAT decreased by 12% in all exposed and post exposed groups (P#0.05). The results suggest that dermal exposure to mixtures of pesticides can selectively induce SOD, CAT and GPX activities in RBC and liver.

Administration, Cutaneous↗

Agricultural pesticide residues in farm ditches of the Lower Fraser Valley, British Columbia, Canada.

Transient and permanent farm ditches flowing to the Lower Fraser River tributary fish streams of British Columbia, Canada, were sampled at several locations in 2003-2004 to determine the occurrence and concentration of residues of selected pesticides, their transformation products, and soluble/extractable Cu++ ions. Of the 43 compounds analyzed, 28 and 22 pesticides were detected in transient farm ditch water and sediments, respectively. About 34% fewer pesticides, however, were found in both matrices of permanent farm ditches. Average concentrations (microg L(-1)) of those most frequently detected in permanent farm ditch water were atrazine (0.20), alpha -chlordane (0.06), desethylatrazine (0.13), diazinon (0.55), dieldrin (0.28), endosulfan sulfate (0.16), glyphosate (6), metalaxyl (0.27); and soluble Cu++ ions (25). Those most often found in ditch sediments (microg kg(-1)) were aminomethylphosphonic acid (AMPA) (2,300), 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) (250), endosulfan sulfate (500), glyphosate (1,225); and extractable Cu++ ions (58,000). The risk potential of these pesticide residues to non-target aquatic organisms inhabiting Fraser River tributary fish streams contiguous to permanent farm ditches is evaluated and discussed.

Agriculture↗

Influence of suspended clay minerals and humic matter on the solid phase extraction efficiency of selected pesticides from water.

The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and alpha-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was > or =0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule.

Acetamides↗

Environmental fate of rice paddy pesticides in a model ecosystem.

The distribution and metabolic fate of several rice paddy pesticides were evaluated in a modified model ecosystem. Among the three BHC isomers, beta-isomer was the most stable and bioconcentrated in all of the organisms. Alpha- and gamma-isomers were moderately persistent and degraded to some extent during the 33 day period. Disulfoton was relatively persistent due to the transformation to its oxidation products. Pyridaphenthion was fairly biodegradable. N-Phenyl maleic hydrazide derived from the hydrolysis of pyridaphenthion was not detected in the organisms though it was found in the aquarium water after 33 days. Cartap and edifenphos were considerably biodegradable, and the ratio of the conversion to water soluble metabolites was very high. There was a distinct difference in the persistence of Kitazin P and edifenphos in the aquarium water. It appeared that the hydrolysis rate of the pesticides affected their fate in the organisms. PCP appeared to be moderately biodegradable. CNP was considerably stable and stored in the organisms though the concentration in the aquarium water was relatively low. The persistence and distribution of the pesticides in the model ecosystem were dependent on their chemical structures. In spite of the limitation derived from short experimental period, the model ecosystem may be applicable for predicting the environmental fate of pesticides.

Animals↗

Determining the role of human substances in the fate of pesticides in the environment.

The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV-radiation, are described. Finally, the photochemical stability to UV-radiation of certain pesticides in aqueous fulvic acid solution is discussed.

Atrazine↗

Effects of pesticides on activities of enzymes and microorganisms in a clay soil.

Laboratory experiments were conducted to determine the effect of 32 pesticides applied at 2 levels on populations of microorganisms, activities of urease, dehydrogenase, phosphatase and nitrogenase in a clay loam incubated for 1 week. Results indicated that a decrease in bacterial number was observed with thiram for 2 days and stimulation with chlorpyrifos after 7 days. Some fungicides and fumigants inhibited fungal numbers for 2 days. The recovery was rapid and stimulatory effects on microbial numbers were evident in many samples. None of the pesticides inhibited soil urease drastically. Formazan formation was not suppressed vigorously by the treatments. With the exception of DD and Vorlex at a high level, none of the treatments inhibited phosphatase in the hydrolysis of p-nitrophenyl disodium orthophosphate. A temporary decrease in nitrogenase activity in acetylene (C2H2) reduction was observed with many pesticides. The low amount of pesticides applied to the clay loam is unlikely to have detrimental effects on soil microbes and the enzymes important to soil fertility.

Acetylene↗

Bacterial metabolism under conditions representing pesticide disposal pits.

Bacterial cultures were incubated with pesticides at concentrations ranging from 1 to 5,000 ppm. The species selected are important in one or more of the following biogeochemical processes: nitrogen fixation, nitrification, denitrification, sulfur oxidation, sulfate reduction, carbon dioxide fixation, and respiratory carbon dioxide evolution. The pesticides used were atrazine, alachlor, carbaryl, parathion, trifluralin, and 2,4-D. Bacterial cultures were exposed to commercial formulations of these pesticides and to pesticide samples from active disposal pits.

Bacteria↗

The relationship between dermal pesticide exposure by fruit harvesters and dislodgeable foliar residues.

Dermal pesticide exposure rates, expressed in mg/hr, by strawberry and blueberry harvesters and dislodgeable foliar pesticide residues were determined in 7 separate field experiments during 1981-1983 in California and Oregon. The pesticides which were studied included captan, vinclozolin, carbaryl, and methiocarb. A positive correlation between these two parameters was found and compared with literature values involving different pesticides and tree crops. The ratio between dermal exposure rate and dislodgeable foliar residues, the units of which are area/time, may have a possible use as an empirical factor for a first approximation of dermal exposure rates by fruit harvesters without the involvement of human subjects.

Adolescent↗

Trapping efficiency of selected adsorbents for various airborne pesticides.

A study was conducted to compare the efficiency of five adsorbents used by government and private laboratories to collect airborne pesticides. Six pesticides, acephate, chlordane, chlorpyrifos, diazinon, heptachlor, and propoxur, were vaporized in a closed system and collected on each of the adsorbents, Chromosorb 102, ORBO 42, ORBO 44 (chlordane and heptachlor only), polyurethane foam (PUF) or Tenax GC, by drawing 250 L of air through the adsorbent. There were no differences in collection efficiency of the five pesticides on Chromosorb 102, ORBO's 42/44, and PUF. The efficiency with Tenax was somewhat less with several of the pesticides.

Adsorption↗

Comparative acute toxicities of selected pesticides to Anguilla anguilla.

The acute toxicities (24, 48, 72 and 96 hr) of eight pesticides to Anguilla anguilla were determined. The organochlorine pesticide, endosulfan was the most toxic, with LC50 values in the range of 0.042 to 0.041 mg/L. Endosulfan was followed in order of decreasing toxicity by diazinon, fenitrothion, chlorpyrifos, lindane, methidathion, trichlorfon and methylparathion. When fishes were exposed to the pesticides tested they exhibited signs of restlessness, erratic swimming, convulsions and difficulty in respiration. This response was more persistent in fishes exposed to organophosphorus pesticides.

Anguilla↗

Pesticides in ground water in the United States: monitoring, modeling, and risks from the U.S. perspective.

Scientific and regulatory interest in ground water contamination by pesticides increased significantly in 1979. This was prompted by findings of the nematicide 1,2-dibromo-3-chloropropane (DBCP) and the nematicide/insecticide aldicarb (Temik) in ground water in several states. Since that time, at least 130 pesticides and pesticide metabolites have been detected in ground water in over 150 studies, but detection frequencies are 4-10% nationally. Detection frequencies of pesticides over Health Advisory Levels are generally lower. Screening-level models and detailed computer simulation models are useful for risk assessments and regulatory decisions. Attenuation Factor, CMLS, PRZM2, GLEAMS, and LEACHM are all useful models.

Environmental Monitoring↗

Hydrotalcites and organo-hydrotalcites as sorbents for removing pesticides from water.

This paper reports on the adsorption of different organic pesticides by hydrotalcite, hydrotalcite heated to 500 degrees C and organo-hydrotalcite in aqueous medium by employing adsorption isotherms, and using X-ray diffraction and infrared spectroscopy techniques. The results suggest that the adsorption capacity of the different materials depends on their nature as well as on the structure, polarity and hydrophobic or anionic nature of the pesticides. The results also show that hydrotalcite, both natural and after calcination at 500 degrees C, is not a good sorbent of hydrophobic pesticides. The data demonstrated that both types of hydrotalcite, however, are very good sorbents of glyphosphate. Furthermore, the organo-hydrotalcites may be as good sorbents as organo-montmorillonites for hydrophobic pesticides.

Aluminum Hydroxide↗

Cord blood-derived plasma factor (CBPF) potentiates the low cytokinetic and immunokinetic profile of bone marrow cells in pesticide victims suffering from Acquired Aplastic Anaemia (AAA): an in vitro correlate.

Cases of Acquired Aplastic Anaemia (AAA) in patients with a long history of pesticide exposure from agricultural fields have been investigated in our laboratory using an immunological approach. These patients showed moderate to severe degrees of bone marrow aplasia as a result of 9-12 years protracted exposure to pesticides which were mainly comprised of organophosphorous and organochloride compounds. The bone marrow aspirate culture was found to be severely deficient both in terms of differentiation and proliferation, and cell mediated immune function (CMI). We attempted ex vivo manipulation of the bone marrow population of patients in two different protocols: in one, stem cell factor (SCF), interleukin-3 (IL-3), and granulocyte-colony stimulating factor (G-CSF) were administered and, in the second set, cord blood-derived plasma factors (CBPF) were supplemented to evaluate the effects, if any. Simultaneously, two control groups including one for healthy normal control (N) and the second, for non-pesticide induced aplastic anaemia group of patients (NPAA) was also investigated for all the above parameters. Active colony formation and improved cellular immune activity (CMI) was observed more frequently in the CBPF treated group rather than that in the cytokine treated group. Surprisingly, administration of cytokines in the first set and CBPF in the second set triggered CD34 (+) cell generation as revealed through flow cytometric analysis (FACS). The effect was more pronounced in the second set. Investigations carried out with NPAA showed relatively insignificant effects with both cytokine and CBPF set up. The investigations indicated that AAA as induced by pesticides could be therapeutically manipulated by exogenous cytokines and growth factors and, more efficiently, by CBPF by way of immunopotentiation through microenvironmental supplementation.

Adolescent↗